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The irrigation of truck crops in the Okanagan valley Palmer, Richard Claxton 1923

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7^e Irrigation  of  Truck  Crops in the Okanakan /alley A 7 IX ftchard Oaxton  Talmer > THE IRRIGATION OP TRUCK CROPS IB THE OKAMM VALLE Y by Richard Claxton Palmer A Thesis Submitted for the Degree of Master of Science in Agriculture in th e Departmen t of H o r t i c u l t u r e . The Univers i t y o f B r i t i s h Columbia . Apri l 1923 . & J/^VJ PLATS I Genera l Vie w o f P l o t s . Augus t 1 5 , 1922 . / . ' i t . Field Equipment used in making Soil Moisture and Soil Temperature Determinations. PLATE II Plot A. Augus t 15th 1922. Thi s plot received 6 inches of irrigation water during the season. Plot "3. Augus t isth, 1?22. Thi s plot received 12 inches of irrigation water during the season. PLAT3 III. «& Plot G. Augus t 1^, 1922. Thi s plot received 18 inches of irrigation water during the season. m i&$. •m Plot i). Augus t 15, 1922. Thi s plot received 24 inches of irrigation water during the season. P1ATE IV . Plo+ A ' Augus t 15,  1922 . Thi s p l o t 6 inche s o f i r r i g a t i o n v/at e •eceived r durin g the season . Plot B. Augus t 15, 1922. Thi s plot received 12 inches of irrigation water during the season. ,— PLATS 7. Plot C. Augus t 15, 1922. Thi s plot received 18 inches of irrigation water during the season. Plot D.  Augus t 15,  1922 . Thi s plot received 24 inches of irrigation water during the season. TABLE O P CONTENTS . TITLE. L'cr • -• The Relation of Irrigation to Human Progress. The Evolution of Irrigation Practices. The Necessity for Irrigation Experiments. The Diversity of the Results of Irrigation Experiments. Discussion of Factors which may explain the Apparent Inconsistency in the Results of Irrigation Experiments. Climate. Soil. Topography. Crop. Cultural Methods. Composition of Irrigation Water. Method of Applying Water. Previous Irrigation. Experimental Technique. THE IRRIGATION OF TRUCK CROPS IE THE OKANAGM VALLEY. Digest of Approved Methods of Irrigating Truck Crops. Justification of this Experiment. STATEMENT OF THE EXPERIMENT. Purpose. Location. Site. General Plan of Procedure. Detail of Procedure in 1920, 1?21 and 1?22. STATEMENT OF RESULTS. Yield Records. Bean. Cabbage. Cantaloupe. Carrot. Corn. Cucumber. Potato. Tomatoe. I RESULTS - Continued. Soil Records. Observations 1920, 1921 and 1922. Daily Range of Soil Temperature. Temperature of the Soil during June, July and August 1922. Soil Moisture Records. Observations 1920, 1921, 1922. Water Holding Capacity of Soil per cent of Dry '.'/eight. Water Holding Capacity of Soil in Inches. Moisture Content of Upper Foot of Soil during Growing Season. Moisture Content of Soil Before and After Irriga-tion. Moisture Content of Soil at Close of Growing S eason. Summary. FACTORS V/HIC B MA Y HAV E INFLUENCE D TH E RESULT S Of f THI S EXPERIMENT Climate. Temperature. Precipitation. Sunshine. Wind Velocity. Relative Humidity. Evaporation. Soil. Cultural Methods. Experimental Technique. CONCLUSIONS. REFERENCES. TEE IRRIGATION OF TRUCK CROPS IN THE OEANAGAN VALLEY. # IN'L'ROTJPC^ION The Relation of Irr.i gatlon to Human Progress Our present day civilisation is closely associated with the development of the Science and Art of Irrigation. No t onl7 is the huge population of India and the Orient supported largely through the artificial application of water to the land, hut the Western peoples, also, owe much of their mat-erial prosperity to the practice of irrigation farming. About twenty-five per cent of the earth's surface receives ten inches or lese of rainfall annually, and can, with our present knowlege, "be made productive only through irrigation. On another thirty per cent of the earth's surface the rain-fall is such that dry farming methods are necessary to pro-duce even the extensile crops, while fo r intensive prcduction irrigation is re.-iired. live n in those areas where the an-nual precipitation is relatively heavy, droughts often occur, during which it is found profitaole to supplement the natur-al rainfall by .irrigation. S o great- is the area of land " A preliminary report nf an irrigation experiment which is hein^ conducted at the Dominion Experimental Station, Si /,^lai,i, P.O . -2-whioh would be benefitted by irrigation that even oould all the water resources of the world be utilized to the full, it is probable that over four-fifths of the earth*s surface would be left thirsting* I n many lands the prosperity and progress of the people will be determined, in large measure, by the extent to which care is taken to make the most econ-omical use of every available drop of water. _3_ The Evolution of Irrigation Practices. The practice of irrigation is probably almost as old as Agriculture itself. I t dates back to the time when primitive man discovered that he could strengthen his hold on life oy giving protection and encouragement to those plants which pro-vided him with food. Histor y records that irrigation had been brought to a high stage of development in Egypt, long before the Christian Era. Indeed , the marvelous civilizations of Egypt and Babylonia cotild never have existed without irrigat-ion, the influence of which prevades the economics, politics, social life, agriculture, legislation, and even the religion of these ancient peoples. V/ e read that in the time of the Pharaohs the rtbasin"system of irrigation was used. I n this system the flood waters were held over the land for some forty-five days per annum to a depth of several feet. Th e times of flood of the Nile, and the climate of Egypt are particularly adapted to this method of applying water; so much so that even today half of Upper Egypt is irrigated in this way. Whil e such a method has certain advantages, in that it minimises the labour of applying the water and of cultivating the land, it also has a very serious defect, since it permits of the applic-ation of water only at flood time. Abou t the year 1320 Mohamed All Pasha changed the irrigation system of L ower Egypt by excavating a number of deep canals capable of dischar-ging the low level summer supply of the Ilile. Th e summer flow, is, however, very limited, and as more land v/as brought under summer irrigation it became necessary to store water, and it -4-is for this reason that the great Assuan dam was built, im-pounding approximately 2,000,000 acre-feet of water. By  the use of this stored supply as a supplement to the waters of the flood period it has been possible to so extend the irrig-ation season that at the present time crops are kept growing every month of the year. Thi s economy in the use of water is largely responsible for the fact that Egypt now supports one and a half persons per acre. The evolution of irrigation has involved the development not only of storage reservoirs, but also of less wasteful methods of distribution. Fro m the "basin" system, with its uneven flooding of the land * the depth of v/ater varying from one to ten feet with the topography - various advances have been made with the idea of ensuring a uniform distribution of water with the minimum loss through percolation, evaporation and run-off. Thus , there are in use today such methods of distributing v/ater as Free Flooding by Contour Ditches, the Border Ditch System, the Border Dyke System, the Furrow or Corrugation,Method, Sub-irrigation and various Overhead Systeme each Method or System adapted to some particular set of condi-tions, but all devised with the common purpose of effecting an economical and efficient distribution of water. Throughout the history of irrigation one fact stands out very clearly. Ther e has, as has been said, been a gradual advance in the direction of more economical use of water. The custom of using v/ater only at flood time, which involved a deluge followed by a drought, has given way to the storage of water in natural or artificial reservoirs, from which it may he drawn.off with the minimum of waste and applied to the soil when the crops are most in need of it. Th e ancient method of applying water in one large application has "been superseded hy the modern plan of delivering water more frequently and in smaller amounts sc that the maximum quantity will he held in the upper soil strata where it is available to growing plants. -6-The Necessity for Irrigation Experiments. The method through which improvement in irrigation prac-tice has been brought about is largely that of experimentation The observant irrigator obtains the answer to the question "how can I make the best use of my available water supply?" by noting and comparing the results obtained by applying various amounts of water to various crops at various times. Although this process of securing information through experi-mentation has doubtless been going on since prehistoric man first applied water to the roots of a plant there still re-mains much to be learned. A s is well known, the actual volume of water required to irrigate successfully an acre of any specific crop is dependent on a large number of variable factors, chief among which are the soil and climatic condit-ions. Therefore , until mankind has acquired a more complete knowledge of the fundamental principles which underlie the correct application of irrigation water, it will still be necessary to conduct local experiments whenever any new set of conditions is encountered. Th e researches of such men as Widtsoe (38), Fortier (?) , Hammatt (17) and Harding (18) have contributed to our understanding of the many "whys" of irrigation practices. Sufficien t insight has not yet been gained, however, to permit of the recommendation of detailed practices in a new district, v/ithout first subjecting these practices to the test of local experiment. The Diversity of the Results of Irrigation Experiments. The truth of the statement that irrigation practices, to be economical and efficient, must be adapted to the local con-ditions existing in any particular district is clearly indic-ated by the diverse results obtained from irrigation experim-ents conducted at the various Experimental Stations in the United States. T o use the work with potatoes as an example. Y/idtsoe(3>6) , working on a gravel bench soil at the Utah Station found that land which received 40 inches^ of v/ater in seven irrigations, produced larger yields, both total and marketable, than did smaller amounts with fewer applications. Results obtained at the same station by 3ichraan(;>2) , showed that the largest yield of marketable potatoes v/as produced on plots receiving a total of only 14 inches of v/ater. I n a sum-mary of five years investigations of the v/ater requirements of the potatoe, Harris(19), also of Utah, makes the statement that "One inch weekly, or a total of 12.8 inches during the season,gave a higher yield than any other treat) ent". Snelson(33), in a report on a series of eight experiments dealing v/ith the irrigation of the potato at Brooks, Alberta, recommends applying a total of 20 inches, and suggests 3 inchen as the most economical depth to apply at one time. Experi -ments conducted in Arizona by LIcClatchie(27) indicated that a total of 18 to 24 inches of v/ater during the irrigation season, used in applications of about Jj inches, v/as ample for "Unless otherwise stated, wherever "inch" of v/ater is used in this report it refers to the depth to which the v/ater v/ould cover the ground. -8-raost potato soils. Pro m extensive experiments and observat-ions covering five years, carried out by Bark(l) at Gooding, Ohio, it appeared that the yield of potatoes tended to in-crease as irrigation water v/as applied up to 26 inches. Welch(2j>) working in the same state found that about 21 inches of water produced the largest yield of marketable potatoes, and that 8 inches gave the largest yield per inch of water. The tremendous variation in the results of these numerous experiments, carried on with the same crop and in each case by trained investigators, demands an explanation. Th e apparen'; inconsistency in these results merely serves to prove con-clusively that the efficiency of various irrigation practices in any particular instance is dependent on the inter-relation of a large number of variable factors, some of the more important of which are: 1. z. 3. 4. ; • >. 7. B. ; • 10. Climate. Soil. Topography. Crop. Cultural Methods. Composition of Irrigation Water. Method of Applying Water. Previous Irrigation. Skill of the Irrigator. Experimental Technique. The variability of these several factors not only con-stitutes an explanation of the diverse results obtained from -9-irrigation experiments in the past, but also suggests the necessity for additional investigations, especially in areas recently brought under irrigation. A n understanding of the effects which change in soil, climate, etc., have, on the economy of various irrigation practice? is nejessar;- before the justification'for local irrigation e:>cperiraents can be fully appreciated. Furthermore , a realization of the fact that cultural methods and the chemical content of irrigation water etc., have an influence on the results of irrigation experiments is essential before an intelligent interpretation of these results can be attempted. It is therefore, considered advisable to discuss briefly, at this point, the bearing of each of these factors upon irrigation practices. -10-Cllmate. The irrigation requirements of crops are affected by rainfall, temperature, hours of sunshine, humidity of the air, and the prevalence of drying winds. Soi l moisture is affected not only by the total rainfall, but also by the time of year at which precipitation occurs. ',;idtsoe(38 ) has shown that light showers during the summer often do more harm than good in that they tend to destroy the soil muloh, thus restoring capillary connection with the damp soil below the surface and facilitating the lass of moisture by evaporation. Widtsoe(;J7 ) has also demonstrated that it is advisable to employ different methods of moisture conservation when the precipitation takes plaoe in the winter than is the case when most of the annual rainfall occurs during the growing season. Investigation s oarried out by ?ortier(12) indicate that temperature is the most important factor in deter- inin^  the amount and rate of evaporation. Fortier(l2 ) is also authority for the statement that evaporation is increased by low humidity and by air move-neat. »idtsoe(>3, ) reports that at Utah the shading of soil from the direct rays of the sun reduced the evaporation by 2.5 per cent. It is quite evident, therefore, that in comparing irrig-ation results careful consideration must ie > j t o meteorol-ogical records. - L-Soil. The most advantageous number of applications and the most beneficial amount of irrigation v/ater to apply, depend largely on the character of the soil and subsoil. Th e presence of humus or decayed organic matter in a soil increases its power to absorb and retain moisture. A  sandy soil absorbs water more rapidly than does a clay soil. Ther e is also greater danger of loss through percolation beyond reach of plant roots where the subsoil is of a gravelly nature, than where the underlying stratum is relatively impervious. It must not be inferred, however, that a layer of imper-vious hard pan near the surface of a soil provides a condition where heavy applications are desirable. Exactl y the reverse is the case, for such soils are easily over saturated result-ing in a condition of soil moisture unfavorable t o plant growth. Similiarly , in soils v/here the water table is near the surface, optimum grov/ing conditions are provided only by relatively small and frequent applications of irrigation water. Widtsoe(42) is authority for the statements that evapor-ation is more rapid from soils of fine texture than from those made up of coarse particles; that v/ater evaporates more quickly from dark-coloured than from light-coloured soils; that other conditions being similiar, a deep soil loses more moisture through evaporation in a given time than does a shallow soil; and that a concentration of soluble salts in the soil retards the vaporization process. Th e observation that -12-it requires less water to grow a crop on a fertile soil, than on one which is deficient in plant nutrients has so much experimental proof that it is regarded as a lav;. ..idtsoe(35> ) in experiments carried out in Utah found that when very small quantities of commercial fertilisers v/ere applied to infertile soils, the number of pounds of water required to produce a pound of dry matter v/as reduced from 1,012 to 459 in the case of a sandy soil, and- from 1,331 to 445 in the case of a clay soil. A series of carefully conducted tests made by Bouyucos (2) indicate that the quantity of v/ater required to produce a pound of dry matter is decreased by an increase in the con-centration, of the soil solution, provided the dissolved sub-stances are plant nutrients. It is evident, therefore, that in studying the results of irrigation experiments, it is of vital importance to make due allowance for the physical and chemical nature of the soil, .as v/ell as for its depth and moisture holding capacity. -13-Topography. The efficiency with which water can he applied to the soil is considerably affected hy the contour, slope and grad-ing of the land. I t is difficult to irrigate abrupt hillsides v/ithout waste, while a gentle slope facilitates the economic-al application of water, wher e land is poorly graded, hollows and hillocks are formed, which result in an uneven distribut-ion of moisture in the soil. A  tract of land sloping to the south, since it is exposed to the direct rays of the sun, loses moisture through evaporation more rapidly than does one with a northern aspect, or one which is comparatively level. The topography of the land, therefore, has a direct bearing on irrigation practice, and its influence on the results of irrigation experiments must be given due consideration. -14-Crop. The irrigation requirements of individual crops vary with their ability to absorb and utilise soil moisture, the extent of their root system and their season and rate of growth. The recent investigations of Briggs(5) indicat e that in any particular soil there must be a certain percentage of moisture to prevent jplants from undergoing permanent wilting, and that in a saturated atmosphere, this percentage of moisture is substantially the same for all plants. I t is common knowledge however, that up to the point where wilting occurs crops dif-fer markedly in their ability to absorb moisture from the soil. Accordin g to V/idtsoe (41) crops which mature early appear to use water more rapidly than those which have a longer growing season. Thus , the short season crops such as wheat and oats are considered to take up water more rapidly than do crops such as corn and potatoes which make a slower growth over a longer season. Th e total water used by the long season crops, however, is often greater than that requir-ed to bring the more rapidly growing crops to maturity. While Lloyd's (25) researches on the physiology of the stomata indicate that plants cannot regulate the rate of flow of the transpiration stream before wilting actually occurs; yet, it is well known that transpiration is far more rapid from some types of plants than from others. Althoug h the stomata are not considered to be adaptive or regulatory in nature, yet, the rate of transpiration from any particular type of plant is greatly influenced by the number, size and -15-Location of the stomata. Thu s in desert plants the number of stomata is greatly reduced. I n some cases transpiration is fur-' ;her limited by the fact that the stomata are located at the >ase of pits or are protected by hfiirs. Furthermore a large number of experiments conducted by such investigators as Leather, King, Lawes, <ollny , Hellriegel tnd Briggs and summarised by Lyon.(2b) prove conclusively that >he quantity of water required to produce a pound of dry matter Is not only different for each type of crop, but that even jlosely related species of the same type of crop do not have the same ability to utilize water. Asid e from the fact that slants vary in their power to absorb and utilize soil moisture Lt is obvious that the economy of various irrigation practices •/ill be affected by differences in the extent of root systems jf various crops. Thus , with a normally deep-rooted crop such is alfalfa, water can be applied in larger amounts than would )e desirable when the more shallow feedin g crops, such as the cereals, are under consideration. Th e importance of this state-aent is emphasized by the fact that recent investigations on the capillary rise of soil moisture conducted by Rotmistrov, 3riggs and other research workers and summarised by Gardner (14/ Indicate that very little of that moisture which percolates be-Low reach of plant roots is available for plant use. In view of these facts it is obvious that in estimating the most economical irrigation practices for any particular locality adjustments must be made to suit the individual w< ter requirement of the crops which are to be grown. -16-Cultural Methods. The imcortance of cultural operations in the conservation of moisture is universally recognized. Tim e and depth of plow-ing, frequency of cultivation, destruction of v/eeds, crop rot-ation, manuring, cover-cropping•, fallowing, and drainage all have a direct bearing on the amount of moisture which is re-tained in the soil for the use of growing crops, les s irrigat-ion water is required v/here crcrs are grov/n in rows, and inter-tillage is practiced after each Irrigation , than v/here the fur-rows are left uncultivated. While recent experiments by Grrantham (1.5) and Thompson (34) suggest that tillage conserves moisture mainly by the eradication of v/eeds, and that the importance of the soil mulch in this connection has been somewhat overestimated, the work of Briggs (3), Portier (10) and V/idtsoe (38) all tends to sup-port the statement that the condition of the top soil as in-fluenced by such cultural operations as plov/ing, cultivation, rolling and packing, does have a very significant incluence on the amount of water lost through evaporation from the soil surface. It is evident, then, that irrigation practices are very closely linked up with oultural methods, and that this fact must be given due weight v/hen the results of irrigation experiments are under discussion. -17-Composition of Irrigation V/ater The results of experiments may be seriously affected by th< mounts and nature of dissolved and suspended substances carriec. own in the irrigation v/ater. Analyse s of river waters ^oj larke (7) indicate that there is a wide range in the propor-ion of dissolved substances which they contain. IVidtso e (4j>) as shov/n that in some cases irrigation v/ater contains in sol-.tion, salts of phosphorous, nitrogen, and potassium, in suf-:icient quantities to supply all of these chemicals required to iroduce a full crop. I n other cases the amount of plant nut-•icnts available from this source is practically negligible. :earney (22) has shown that the concentration of saline solu-,ions which plants can withstand is influenced not only by the mount of. such injurious salts as magnesium sulphate and sodium sarbonate which are present, but also by the proportion between ;hese salts and others such as calcium sulphate and magnesium jarbonate, which act as antidotes. Hot only is the soluble matter in v/ater important from the standpoint of irrigation, but suspended matter, also, may play i significant role. Forbe s (8) reports that in Arizona the sediment from one seasonTs irrigation frequently covers the Land to a depth of from 4 to 6 inches. Th e tremendous fertil-iser value of the overflow of the Nile, heavily laden v/ith sus-oended matter, is well known. In attempting to understand the response of a crop to var-ious applications of water, attention must therefore be paid to the chemical analysis of the water used. -13-iethods of Applying Water The ideal system of irrigation is that which, with the liniraum loss of water through oercolaxion, evaporation, trans-piration and run-off, ensures the most uniform distribution of loisture throughout the soil v/here plant roots are feeding, n actual practice the system of distribution adopted depends n many factors such as the nature of the soil, the topography, nd th e intensity of cultivation. Thu s various systems of 'locding, of overhead irrigation, of furrow distribution, and f sub-irrigation have been devised to meet the particular con-itions which exist in each irrigation district. Wate r losses hrough excessive transpiration, evaporation, percolation and •un-off are not the same for these various systems of distrib-ution. Fo r instance, Fortier (I3>),in a summary of investigati-ms conducted at IReno, Hevada, states, that not only was the oss through evaporation less where the furrow method of ir-rigation was used than was the case when flooding v/as practic->d, but that an increase in the depth of the furrow gave a larked reduction in the exaporation loss. Th e length of the "urrow is also an important factor, since v/here the furrows ire unduly long a large excess of v/ater sinks into the soil at ;he upper end of the field and percolates down belov; the reach )f plant roots. It may be readily comprehended, therefore, that the method if applying water can very materially affect the results of irrigation experiments. - 1 -Previous Irrigation In a consideration of the irrigation requirements of crops account must be taken of the number of seasons irrigation has aeen practiced. Tha t continued irrigation has a cumulat-ive effect on the soil moisture is an established fact. I n extreme cases of over irrigation the v/ater table may be broug-ht undesirably near the soil surface, while it Is common ex-perience that when a new tract of land is brought under irrigation more water must be applied the first few years than is the case after the subsoil has become thoroughly moistened. Furthermor e the researches of Cameron (6) have shown that the physical nature of a soil is profoundly in-fluenced by the application of irrigation v/ater. It is important, therefore, to take into account the previous irrigation history of land where irrigation experi-ments are carried out, as well as to make allov/ances for the amount of moisture present in the soil and subsoil at the beginning and close of an experiment. -20-S'fcill of the Irrigator The efficient ixtilization of irrigation water depends largely on ixniformity of distribution. Probabl y the most important factor in the reduction of wastage through uneven distribution of moisture, is the skill of the irrigator. Th e capable and experienced irrigato r so handles the water as to reduce to a minimum the losses through evaporation, percolat-ion and run-off. Inexperienc e and ineffieieucy on  th e part of the irrigator result in extravagant and wasteful use of water. The efficiency of the irrigator, therefore, has a great deal to do with the success or failure of any particular irrigation practice. 21-ExperiTiental Technique. It ia only within the last deoade that investigators have ome to a full realization of the very significant role which eohnique plays in determining the reliability of experimental esults. Suc h research workers as Kiesselbach (2~j>)  , Hall (16), ood (44) and Pickering (2^) have shovm that serious errors may reep into the results of experiments not only through failure o employ sufficient care in planning and carrying out a proj-ct, but also through the adoption of faulty methods of inter-retation. I t is now recognized that the results obtained rom an experiment may be completely invalidated owing to the ffecta of soil heterogeneity, competition between adjacent ows, failure to eliminate border rows, incomplete stand, etc. arioua suggestions for the reduction of experimental error to i minimum are advocated by the several investigators, but all re agreed upon the necessity for conducting experiments over , series of years and for the frequent replication of plots. It ia altogether probable that differences in the techni-ue of planning experiments and of interpretating data are 'e8ponaible for a great deal of the apparent contradiction in he reault8 of irrigation experiments. Prom a consideration of the poseible influence of the ibove factors on the results of previous irrigation experiments t ia clearly apparent that the results secured in other irri-gated areas should not be accepted as applying directly to Iritish Columbia conditions. -22-I5RI5ATI0N OF TRUCK PROPS I If THE OKANAGAN VALLEY. In attempting to ascertain the irrigation practices most dapted to the production of truck crops in the Okanagan Valley t v/as deemed advisable to conduct local experiments. I n order o avoid unnecessary duplication of effort, advantage v/as taken f the work of other investigators who had carried out experi-ents along similar lines. A  careful study v/as made of the esults of numerous experiments conducted in the irrigated sec-Lons of the United States. Fro m a survey of these results, anc knowledge of the local conditions of soil, climate, etc., it as possible t o predict with a fair degree of accuracy, these rrigation practices which v/ould be most likely to meet v/ith access in the Okanagan Valley. -2> igest of Approved Kethods of Irrigating Truck Props. The following is a digest of the general observations of idtsoe (40) and Fortier (11) concerning the irrigation of ruck crops. Most truck crops can be grown successfully under the clirn-tic conditions which prevail in irrigated regions. Where irrigation is practiced it is possible to obtain rofitable yields of truck crops on a wide range of soils. est results are secured, however, on loose friable soils with ood under-drainage. For success in the production of truck crops under irrig-tion it is of primary importance to maintain the soil in a igh state of fertility. Som e system of rotation involving the se of a legume is advisable, in order that both the nitrogen nd the humus content of the soil may be replenished. Contin -,ous cultivation without the use of cover crops or manures soon xhausts the soil and causes yields to decline. . Befor e planting truck crops the land should be carefully ;raded and leveled to facilitate the uniform distribution of rrigation water. It is important to have the soil in such good physical con-.ition that it absorbs and retains moisture readily. Thi s can nly 'be accomplished by practicing approved methods of soil lanagement, such as deep fall plowing followed by thorough reparation of the soil before planting. Cultivation should be practiced after each irrigation and several times between irrigations. A  dust mulch should be -24-laintained. until the plants shade the soil, or until the grow-ih of the crop prohibits farther use of the cultivator. Th e iOil should be worked deeply at first, but as the season ad-ances the cultivations should be made shallower to avoid njuring the root system o£  the plants. All in all, the furrow method o f irrigation gives the most atisfactory results with truck crops. Sub-irrigatio n is feas-ble only in a few localities where the lands are naturally ub-irrigated. Floodin g is conducive t o sun scald, tends to njure the physical condition of the soil, and results in great oss through evaporation. Overhea d Irrigation is expensive to nstall, and requires clean water under considerable pressure o ensure efficient operation. Lik e flooding it involves great oss of water through evaporation. V/her e the furrow method s employed it is universally conceded that less water is re-quired where comparatively narrow, deep furrows are used, ince less v/et soil is exposed to evaporation than is the case here wide shallow furrows are made. Th e loss of water through ercolation is much greater with long furrows, than is the case here the water is run for only a short distance. Run s of xeater length than 300 feet are inadvisable, while in porous oils best results are secured with much shorter furrows. There should be moisture enough in the soil in the spring 0 germinate the seeds v/ithout further irrigation. Wher e the atural winter precipitation is not sufficient to moisten the oil to the full depth of root action, winter or fall irrigat-on is of advantage. Th e question of whether, in the event of -a5-iere being insufficient moisture in the soil to ensure rapid id complete germination, it is preferable to apply water just jfore or just after seeding is still undecided; both practices "e to be avoided whenever possible. ,. The first irrigation should be postponed as long as possibL fter planting, because early irrigations bring the root system ) the surface, which in turn means a large, wasteful use of iter later in the season. ). Wate r applied late in the season causes late growth, thus slaying the period of maturity. L. Truc k crops as a whole are most in need of irrigation dur-ig the months of July and August. I. Th e amount of water which it- is advantageous to apply at le time varies with the crop and the local conditions, but it 3 seldom advisable to apply more than 8 inches at a time while or 4 inches is an average application. 5. Th e total amount of water which can be applied to advantage aring the growing season depends on the nature of the crop and a local conditions, but applications of more than JO inches re seldom economical; while frequently the most profitable Lelds are secured where smaller amounts of water are applied, he increased yield due to the increase in irrigation is not roportional to the added quantity of water. Man y crops are eriously injured by over irrigation, v/hile the produce of ighest quality is invariably obtained v/here water is applied a medium rather than in large quantities. 4« '.'.'her e the soils are deep and well cultivated and where the nual rainfall is from 10 to ljj inches good crops of the llowing vegetables <5an be produced with the amounts of v/ater dicated. ans 1 0 to 1^ inches. Cabbag e 2 4 to j>Q  inches rrots 1 8 to 24 "  Cor n 1 0 to 15 » ntaloupes.. .10 to 12 "  Potatoes. . 1 5 to 24 • • Ttatoes 1 2 to 18 " V/ater may be economized, and a greater quantity handled by e irrigator v/here distributing devices, such as flumes with equent adjustable gates, are employed. The maintenance of uniform conditions of soil moisture is e key to success in the irrigation of all truck crops. The acceptance of the above general information concerning rigation practice as applied to the production of truck crops rrov/s the necessary scope of local experiments, but does not iminate the necessity for conducting local irrigation invest-ations, especially in a region such as the Okanagan Valley are conditions are decidedly unique. justification of this Particular gxperiment. In the Okanagan Valley there are thousands of acres of ?ertile land over which the precipitation is such that satis-factory yields of fruit, truck, and farm crops can be secured mly by the artificial application of water to the soil. Ifith irrigation, however, the conditions become highly favour-able to crop growth. Truc k crops such as tomatoes and canta-loupes thrive particularly well in the southern end of the ralley, while onions and potatoes are grown extensively in the lorth. Th e total acreage of the Okanagan Valley to which wate:' 3an be applied with profit depends on many factors, such as the fertility of the land and the cost of installing distrib-ition systems, but is limited in the final analysis by the quantity of water available for irrigation purposes. Ther e is not sufficient water available, at reasonable cost, to irrig-ate all the thirsting agricultural land in the Okanagan. I t is therefore imperative that the available water be used v/ith care and economy so that it may be ma.de to cover as much land as possible. In order that the most economical use may be made of the irrigation resources of the Okanagan Valley it is a vital necessity that accurate information be secured as to the quantity of water necessary to ensure optimum development of the crops grown. Suc h information provides a sound basis for calcultaing the amount of land which can be served to best advantage by the available water supply. Furthermore , a knowledge of the irrigation requirements of individual crops -28-3 of inestimable value t o the grower, sinoe it enables him to ;ilize the water at his disposal, when and where it v/ill give •eatest returns. Realizin g that trustworthy information as ) the conditions of soil moisture most favourable to the pro-Lction of specific crops is essential if losses due to faulty :rigation practices are to be avoided it v/as decided to con-ict local irrigation investigations in the Okanagan Valley. Previous to 1?14 no accurate records had been kept of the >lume of water used in the production of crops under Okanagan mditions. I n that year the Federal Department of Agriculture stablished an Experimental Station at Summerland. Measurin g jvices were installed at this Station, and detailed records re being kept of the quantity of v/ater supplied to the various cops produced. This report deals chiefly with an irrigation experiment istituted at the Sumner land Station in 1920. Th e project v/as adertaken to obtain information as to the irrigation require-snte of those truck crops grown extensively throughout the tanagan Valley. T o ensure reliability in the results secured his experiment must of necessity be carried on over a number C years. However , it is considered that sufficient informat-Dn has already been secured to justify the compilation of his preliminary report. -29-STATEI.ISNT 0? THS EXPERIMENT. irpose of the Experiment. A comprehensive investigation of the irrigation require-ints of truck crops v/as started in 1920 at the Summerland rperimental Station. Th e primary object of this experiment is obtain reliable data concerning the water requirements of irious truck crops when these are grown under the soil and .imatic conditions which prevail in the Okanagan Valley. In -irmation is being sought v/ith regard to the most advantageous: 1. Amoun t of irrigation water to apply per season. 2. Tim e to apply irrigation water. 3. Frequenc y v/ith which to apply irrigation water. 4. Amoun t of water to apply at each irrigation. The project has also a seoondary purpose: to demonstrate r a concrete illustration, the efficiency and the feasibility • practicing approved methods of irrigation farming in the 'eduction of truck crops in the Okanagan Valley. ocation of the Sxperin ent. This experiment i s bein? conducted at the Sumrnerland perimental Station. Th e environment of this station is pical of conditions as they exist over much of the bench nd of the Okanagan /alley . ,it h respect to climate, authentic teorological records indicate that the precipitation and mperatures experienced at Summerland are midway betveen those countered at the northern and Southern extremities of the 11 ey. The soil, like that of much of the Okanagan bench land, is nature lacking in humus and nitrogen, but gives no indicat-n of being deficient with regard to mineral plant nutrients. It is evident, therefore, that the location of the project such that the results secured may be considered to apply to large area of the Okanagan Valley. - 1 -ite of tne Experiment. The project is being carried out on a block of land which as an Eastern aspect. Ver y little grading was necessary to ender the slope ideal for furrow irrigation. Th e soil oonsis-s of about two and a half feet of fertile sandy loam, under-aid with a subsoil of fine sand. Suc h conditions, though by o means general in the valley, are nevertheless representative f much of the land devoted to truck crops. Previou s to 1920, hen this experiment was started, the cultural treatment of he block of land selected as a site had been such as to pro-ote uniform fertility. N o barnyard manure or commercial ertiliser had ever been applied. Th e block had been operated s a unit and had received the following treatment:-1914 - Plowed. 1915 - Planted to Oats - no irrigation - crop harvested. 1916 - Planted to Oats - irrigated - crop harvested. 1917 - Planted to Potatoes - irrigated - crop harvested. 1918 - Planted -to Vetch - irrigated - crop plowed under. 1919 - Planted to Vetch - irrigated - crop plowed under. -32-t was planned:-1. T o carry on the experiment for at least five years. 2. T o measure out from a block of land of uniform fer-tility, eight equal plots, each a fraction of an acre in area. 3. T o plant four of these plots to truck crops and four to vetch each year; the vetch to be plowed under as a cover crop. 4. T o maintain the productivity of the soil by rotating the truck crops with the vetch; thus each plot would be planted to vegetables one year and to vetch the nex 5. T o practice approved methods of soil and crop manage-ment. 6. T o apply v/ater at the rate of 6, 12, 18 and 24 inches respectively, to each vegetable plot, and to each corresponding vetch plot; the v/ater to be applied by the furrow method of irrigation. 7- T o make careful observations of the comparative growth and condition of the crops in each plot at regular intervals throughout the growing season. 8. T o record indications of drought and unfavourable moisture conditions as they were observed. ?. T o harvest and weigh each crop as it reached market-able condition. 10. T o prepare a Btumnary of the results obtained. -33-ocedure in 1?20. The entire bloch of land, <- elected as a site for the ex-riment, was plowed and harrowed on Mar 12th. Eigh t plots, eh 1./20 acre (21* x 103.7*) i-" area were then measured out d designated A, 3, C, D, and A', B», G», J'. Plots A', ? 1 . T, enc i Df ve^e t>p-i sc^a t n vot.' 1". mrin g e season these plots received, respectively, the same amount ' water as was applied to the corresponding vegetable plots, te vetch was plov/ed under early in July, and bhes e plots were 1lowed for the remainder of the season. Owing to the fact that t1^ land was plowed late in the iring there was insufficient oC the natural precipitation ,ored in the soil '•.  c cos-re gooO germ' nnticn o^ truc^ crops, tnsequently the sowing of the vegetables was deferred until 'ter the first irrigation had been applied. Uhi S was not 'fected until June 12th, Althoug h it was realized that the wing of seeds immediately subsequent to irrigation La a prac-ce to be avoided whenever possible, yet, in view of the fact lat the season was already well advanced it was considered Ivisable to proceed with the planting as soon after the first "rigation as the soil could be worked into a good seed-bed. jcordingly plots A, B, C, and D were cultivated on June 14th, id planted to vegetables on June 15th. In the selection of vegetables to be grown in this experi-»nt it waa considered advisable to include widely divergent /pes, since such a procedure would permit a ready comparison r the water requirements of root crops, foliage crops, and -34-rops grown for their fruits or seeds. Car e v/as taken, how-ver, to choose only types and varieties of recognized commer-ial importance in the ukanagan Valley. even rows of vegetables were planted in each plot - the rows eing 3' apart and 103«7f lontr . Th e method of planting v/as dentical for each -olot and each crop series. Eigh t species f ve~etaole were used. Th e following table shows, for each rop ,.nd for each plot; tne ro./ number, variety and method of Ian ting. Table I. Pla n and l.ethod of Planting each ov/ o. Cro p Crop an d i^ac h P l o t . /ariety Lethod of Planting. Potato Jerse y Royal Cucur.oer Davi s Perfect Carrot Ohcdite-ia y Canta loupe r.oodo o Cabbage Danis h 3 a l l head Bean s t r i n T i e s s i r een Po d Tomato E a r i i a n a Corn Golden bantam Cut to 2 eyes - planted 16" apart. 5 seeds in a hill - hills 3» apart 1 os. to 100 ft. drill. 3 seeds in a hill - hills pT apart. 1 i..onth old plants set It!" apart (^ row). 1 pt. to 30 ft. drill (-£ row o v/eek old plants set ;>' apart. 5 seeds in a hill - hills 3' apart. ..here termination of the first sowing of seed was insuf-cient to ensure a uniforrr. stand of plants a second sowing was de in an attempt to fill up tne blanks. Th e method of thin-ng, training, etc. , .-as the same for each crop series; thus rnatoes in all plots were pruned to a single stem and trained ,0 stakes, corn, cucumbers, and cantaloupes were, in all cases ,hinneci to one plant to a hill, carrots were thinnei to two nches, and beans were Water was applied thinned to six inches. D.7 the furrow method* Th e furrows were 'un out with a small single horse X J1O /, one farrow being plac-id between each tv/o ro\ •ater applied, a Miner' ra of vegetables. Fo r recording the s Inch 3ox was used. Th e unit of leasurement adopted was tie &cre Inch, the exact etp.ivt.lent if an inch of rainfall. .11 plots on June 12th The first irri.j tion 'a s applied to subsequent applications being made at fortnightly intervals until eac:. "lot had receivea its Quota* The following table gives the plan on which v/ater was ipplied. >lot L 3 t 1 ) Table 11. lla n for Application oi Water. Dates v/hen Water was Applied. June 12 & 28. July 12 June 12 & 28. July 12 & 28. June 12 & 28. July 12 & 28. Ausust 12. June 12 & 28. July 12 & 28. Aug. 12 & 28. Cultivation was j as the soil v/as in cox occu red between irrigc Amount of Water Applied at each Irrigation. 2" 3" 3.6" 4" i]o. of irrigat-ions per oeaoon. 3 4 3 o Total Mater applied per season. 6" 12" 18" 24" )racticed as scon after each irrigation idition to be worked. Whe n showers it ions a dust mulch v/as re est ablished y additional cultivations. Similarly , even after any plot ad received its quota of v/ater, cultivation v/as still contin-sd until the soil v/as adequately shaded by the crop. Dee p .iltivation v/as practiced early in the season to encourage the Lants to root deeply and to keep the soil in good condition Dr absorbing moisture. A s th e season advanced cultivation v/as ide shallower in order to avoid undue disturbance of the root astern of the crops. A careful survey of the growth and condition of crops v/as ade at monthly intervals from the date of planting. A  record as kept of all drought injury and of conditions of crop rov/th indicating an unfavourable moisture supply. Th e crops ere harvested and weighed when they reached marketable con-ition. Thus , beans were picked as soon as the pods were large QOugh to be sold as green beans; cabbages were cut when the eads were well formed; cantaloupes were gathered when ripe sough to ship; carrots when large enough to store for winter se; corn when ready to serve on the cob; cucumbers when they eached marketable size; potatoe s when ready to dig for inter use; and tomatoes as the fruit ripened. Whe n the crops ere weighed a record was kept of both marketable and unsale-ble produce. At the close of the season a summary of the field obser-ations was compiled, and the yields were tabulated, Llarket -ble produce only was included in the tables of yield. rocedure in 1°? L. The procedure followed In 1921 was substantially the line as that outlined for 1920, with the f ol 1owing modificat-ions. Th e entire block of land was plowed in the Fall of 1920, id was disced, floated, arid harrowed early in the Spring of ?21. B y this means sufficient cC the natural precipitation is preserved to germinate all seeds without irrigation. Consequently i t was possible to have all crops well started efore any irrigation water was applied* The  plot s on which egetables had been grown in 1920, were sown t o vetch early n May end the vetch was plowed unde r in July. 3?h e plots whici ad been sows to vetch the previous year were planted to egetables. Th e planting plan adopted was the same as that sed in 1?20. Wate r was applied as in the previous year ith the exception that the first irrigation was given on June st instead o f Tunc 12th. Subsequen t applications being made t fortnightly intervals from June 1st. & S in 1920 the plots n which vegetables were planted were designated A, 3, C, and I, while the corresponding vetch plots were given the letters t , Bl, 0' , and X)'. -58-rocedure in 1922. The same procedure was followed in 1922 as in 1921 with he modifications and additions noted below. Th e vegetables ere planted in the plots where vetch had been turned under a 1921. I n each plot the vegetables were moved one row over rom the location occupied in 1920, it being considered advis-ble not only to rotate the vegetables with the vetch, but lso to practice a rotation of the vegetables v/ith each other. he first irrigation was given on June 8th, and subsequent pplications were made at fortnightly intervals from that date, he final irrigation being applied to Plot D on August 17th. n addition to the yields and field observations recorded in revious years, data were secured with regard to the soil oisture and soil temperature at various times during the grov;-ng season. Eac h plot was designated by the same letter assig-ed to it in 1920. .• w The results secured from this experiment in 1920, l?2l and 22, are set forth in the following pages. Th e yields obtain-here the ; s of water were applied are present-in tabular form. Th e tables showing the effect of a.ppl rious te r to each variety of r e llo iat a presented, and Id notes I  to per cent of gerrnin-Le produ 3 . I n the case of . rs and tomatoes, tables en coinpiled to indie t ] date s when 1 )le conditj .  iino e the potatoes, cab! re eac ratio n it is not I l e to is of J te d data, the effect whiol plio -ion of ate r had on the i o f til iGuired to or.' . Soil temper A  soil e  obee I f in 20 and 1521 ar Ode r sep;. re detailed s e obser~ s  collected in 1* e embodied in t •  table s are 7  a rmatio: b ! y contain, and an attem-- is made to correlate this -40-" . The following tables show, for each variety of vegetable d for each plot:-Amount of water applied at each irrigation. Number of applications each season. Total water applied each season. Yield per plot in 1920, 1921 and 1922. Average yield from each plot. Average yield from each acre. Relative yield from each acre. Average yield from each acre inch of water. Relative yield from each acre inch of water. . Date when crops reached marketable condition. • It is recognized that, when acreage yields are computed 'Om the results of experiments conducted on a small fraction I an acre, any experimental error is greatly multiplied. iwever, it is considered probable that the relatio . between le yields secured in the various plots is substantially the one as v/ould be obtained under field conditions. I t is for lis reason that the figures showing the relative yield are (eluded in the tables. I n computing these figures the yield :om Plot B has been taken as the standard and given the value i 100. Th e yields from the other plots have then been expres-jd as a percentage of the yield in Plot "3. Thi s method of cpreseing yields on a percentage basis presents, in a form lich can be readily comprehended, the comparative yield secured 1 the several plots. I 'aDie i l l • i x e i a a e e u r e a i r a i n n e a u s ^ D a x u ^ e oo J I C C D rvu.j When Var iou s Amount s o f Wate r Wer e A p p l i e d . Plot A 3 G D Applications of V/ater Amount Applied at each Irrigation ins. 2 7 3-6 4 Number of Ap-plic-ations : 4 7 b Amount Applie< each Season ins. 6 12 IE 24 Yield per P I 1920 lbs. 44.00 64.25 .59.00 1921 lbs. 33.23 41.23 30.73 31.73 lot 1 280 1922 lbs. 39.00 40.25 47.25 45.75 Acre Average 11) s. 3 •' • - -45.92 47.42 45.50 Average Yiel d per Actual lbs. 11,038 12,858 13,278 12,740 .acre itive % 85.8 100.0 105.5 99.1 Average Yield per Acre Inch of Water. Actual lbs. 1,072 738 531 Relative i 1" 171.6 100.0 68.9 Date Ju ly 13 18 25 29 Aug. 3 c > 10 17 23 30 S e p t . 8 T o t a l P l o t A l b s . 3 16.50 12 5 q . 5 0 44 L U U J . C J . 1920 P l o t 3 l b s . . 7 5 11.25 1 2 0 7 4 .25 5 c . 25 • XJtzx.  u o v i i i i g i i P l o t G l b s . 1.25 9 .25 1 5 23 6.25 9.25 64.25 P l o t D l b s . . 7 5 9.25 8.50 28 3 9.:.0 59 Condi-P l o t l b s 2 7 5 5 6.50 4 .75 5 35 .25 t i o n . 1921 A P l o t • l b s . 4 12 6 10 2.50 2 .75 4 41 .25 3 P l o t l b s . 1.50 8 5 2 3.30 1.75 3 30 .75 G P l o t J D l b s . 7 5 0 4 0 0 2.50 5 .50 ; 31.75 1922 P l o t A  P l o t I l b s . 1 1 '3. 2 3 -12 9 8.50 8.50 8.2 5 . . ' .  7 2 .50 3 1.75 2 39 40 .2 5 i i r i o t 0  r i o t . 1 l b s . 1bB . ; - - 5 5.^ 5 11 1 4 8.50 6.5 0 6.50 5 .2 5 11 9 .7 5 4 4 3 3  . 47 .25 45 .7 5 -43-A study of Table III reveals the fact that applications more than 18 inches (3.6" x 3)w o f water per season actually used a reduction in yield per acre. Furthermore , there was increase in yield per acre in 1921 when more than 12 inches " x 4) was applied, while in 1920 and 1922 the increase brou-,t about by the application of more water was only very ight. I n all three years a satisfactory yield v/as secured ere only 6 inches (2"x 3) was used. B y far the greatest eld per acre inch of water was obtained where only 6 inches ;"x 3) was applied. Table IV shows that the crop reached marketable condition 0 weeks earlier in 1921 and 1922 than was the case in 19 20. is difference in date of maturity can no doubt be attributed .rgely to the fact that the seed was sown almost a month ear-,er in 1921 and 1922 than v/as possible in I92O. Th e larger iplications delayed the date of ripening in 1920 and 1921 but ipeared to have little effect on the date when the crop reach-1 marketable condition in 1922. Th e crop v/as observed to be iffering from drought in Plot A during the month of August \ each year, but the yield does not seem to have been greatly sduced from lack of moisture even in this plot, v/hich receiv-L only 6 inches (2"x 3) of water during the entire season. In 1920 when irrigation v/as practiced immediately pre-.ous to seeding the per cent of germination was considerably sduced v/here the larger applications of water were made. (3.6"x 3) indicates 3 applications of 3.6 inches each. -44-Prom these results it would seem that, under Okanagan onditions and where good cultural methods are followed, there little to be gained form the application of more than 12 ches (3Hx 4) of irrigation water to beans. - 4 3 -P l o t A 3 p D ore A p p l i e s Amount A p p l i e d a t e a c h I r r i g a t i o n i n s . 2 . 3 . 6 4 T a b l e a t i o n s o Number of Ap -p l i c a -t i o n s ; 1 5 6 As i n d i c a t e d b y t h w h e r e 2 4 i n c h e s ( 4 e l y .v i i n e a c h i n c r e a s e v / a t e r shov / t h a t V. Y i e l When f "Vate r A p p l i e d e a c h S e a s o n i n s . 0 12 18 24 d S e c u r e d fro m Cabbag e ( D a n i s h B a l l V a r i o u s Amount s o f V/ate r w e r e A p p l j e  3  -Head) Y i e l d p e r P l o t 1  A c r e A v e r a g e Y i e l d 2B0 p e r A c r e . 3 92J 192 1 192 2 A v e r a g e A c t u a l l b s . l b s . l b s . l b s . l b s . 5 9 . 0 1 2 4 7 3 2 . 7 9 , 1 5 6 4 9 . 3 1 6 .9 1 3 2 . 2 1 4 , 6 1 6 6 0 . 3 2 3 10 8 6 3 . 8 1 7 , 8 7 2 4 8 . 7 3 3 12 7 6 9 . 6 1 9 , 4 8 2 R e l a t i v e X 6 2 . 6 1 0 0 . 0 12 . ; 1 3 3 . 3 e d a t a p r e s e n t e d i n T a b l e V , Cabbag e gav e t h e h i g h e s t »x 6 ) o f & v e r a e p e r a c of A c t u a l 1 1 ,526 1 ,218 993 812 p r o d u c t ;e Y i e l d r e m e n v / a t e r R e l a t i v e • 1 2 5 . 3 100 8 1 . 3 6 6 . 6 i o n p e r w a t e r wa s a p p l i e d ; Th e y i e l d p e r a c r e i n c r e a s e d p r o g r e s s i v -i n t h e amoun t o f v / a t e r , b u t t h e f i g u r e s f o r j t h e i n c r e a s e i n of w a t e r v/a s n o t c r o o o r t i o n a l t o y i e l d b r o u g h t a b o u t b y a p p l y i n g mor e ' i e l d p e r i t h a n 6  . : t h e i n c r e a s e i n t h e amoun t o f v / a t e r a p p l i e d a c r e i n c h of • I n c h e s ( • 2"x 3 ; -46-In an attempt to calculate the most profitable amount of iter to apply to cabbages account must be taken of the relat-n between cost of water, rental value of land, and cost of oducing the crop. Th e fact that the application of 24 acre ches (4"x 6) of water per acre resulted in the highest yield r acre does not necessarily indicate that it is, in all ses, advisable to apply this much v/ater. A  greater net Te-rn may often be secured by spreading the same quantity of ter over a larger area of land. Th e heads produced, where ss than 18 inches (3.6"x j>) of vmter was used, were, however, 1 such inferior size and quality that it seems to be doubtful ether cabbages can be produced commercially on the soil most evelent in the Southern Okanagan with less than this quant-y of water. Unde r the conditions of this experiment fairly ^tisfactory yields v/ere secured with 18 (,5.6"x jj) and 24 "i 6) inches of vmter, but the soil is rather light for this *op, so that even where these relatively large quantities of .ter were used the yields were somewhat belov; the requirements ir successful commercial production. [ lc I A C D Table Application of \] Amount Numbe r Appli ed o f Ap-at each plio -Irrigation ations ins. 2 3 3 4 3.6 3 4 6 71. Jl e Id Seoured from Cantaloupes (Hoodoo) When Various Amounts cf 'ater Amount Applied each Season ins. c 1 18 24 Yield per 1920 lbs. 133.0 227.3 136.23 133.0 1921 lbs. 38.0 54.0 Water were Applied. Average Yield plot 1  acr e Averag e Yield pe r Acre Inch 140 pe r acre o f Water 1922 lbs. 131.3 I98.O Average Actual Relative Actua l Relative lbs. lbs . %  lbs . lbs . 116.0 16,24 0 70. 1 2,70 7 140. 2 163.3 23.17 0 100. 0 1,93 1 100. 0 137.4 19,23 9 83. O 1,06 9 33- 4 132.0 18,48 0 79- 7 70 7 36. 6 Date ug.23 to 3ept2 4 6 8 ° 11 13 L6 18 20 23 24 P l o t • lbs 15. 6 A 75 J O O I O T A X * 1920 P lo t B l b s . P l o t l b i . C * r o o v » P l o t 108. 1) Oondition. P l o t lbs . A 1921 P l o t B l b a . • 75 ' v*— ' P l o t l b s , 0 "J. .-. v P l o t l b s . i) P l o t A l b s . 81.50 30 ') L0 V 5 6 5 --1922 P l o t B l b s . 27 51 l.u 2? 27 51 32 20 -7 P l o t C l b s . 3 20 22 15 24 38 30 28 8 10 P l o t D l b s . 12 22 16 6 19 ^ 39 34 10 16 ,n v'gyr.».'if— Date Sept29 O c t . l 6 ; 13 16 20 23 26 27 T o t a l 1920 P l o t A  P l o t B l b s . l b s . 4 .75 3-3 0 6.30 1.25 7.5 0 3 .75 3-3 0 --73 6 8 - 6 2 26 4 1 6 4 2 133 227.3 c The da t a i nco r p P l o t G l b s . __ 3.2J3 1.23 13 45. 3.75 4 ; 59 : 136.23 c r a t e d * • « » " • — * " " * » •  • * - -P l o t D l b s . — — 7.73 4 .30 3 .23 -»,<,(• -0 , 31 i n Tabl e p e r a c r e o f marke t ab l e c a n t a l o u p e s a p p l i e d , v/hil e i n 1?2 1 6  i n ches (2 " P l o t A l b s . — 3.30 — 6 — — " 3.6 61.30 VI in d \ " " 1921 P l o t l b s . - *  w  *  .  -  / 1922 B P l o t C  P l o t D  P l o t A  P l o t B  P l o t 0  P l o t D l b s . l b s . l b s . l b s . l b s . l b s . 1.23 L • 11 15 56 i c a t e v/as s ecu re d w x 3 ) gav e t h e -3 1 ^ 3 3 54 131.3 0 21 3 19 8 ;.: < ; t h a t i n 192 0 an d 192 2 t h e g r e a t e s t y i e l d here on l y 1 2 i n c h e s (3 t t x 4 ) o f v/a te r wa s a t e a t tonnag e o f m a r k e t a b l e p r o d u c e . -50-all cases the yield per acre inch of v/ater was greatest when Ly 6 inches (2"x 3) of v;ater v/as used and the efficiency of i water decreased rapidly as larger applications were made. ; information set forth in Table VII shov/s that the crop was ry late in coming to maturity in l?2l. Thi s was due largely the fact that the first sowing of seed failed to germinate, I a second sowing had to be made well on in June. I n each the three seasons there v/as a very remarkable postponement the date of maturity v/here the larger amounts of v/ater were slieS. Th e produce ripened first in the plot v/here only 6 jhes (2"x 3) of water v/as used, but a considerable percentage the cantaloupes produced in this plot vrere too small to be Leable. Th e undersized fruits are not included in the tables Dv/ing yields of marketable produce. In 19 20, v/hen v/ater v/as applied immediately previous to 3ding, germination v/as markedly v/eaker where the larger Dlications were made. I t is evident that the application of re than 12 inches (3"x 4) of water during the season v/as tually injurious to cantaloupes, in that it reduced the yield r acre and delayed the date of maturity. Unde r the condit-IS of this experiment the application of 12 inches (3"x A) v/ater during the season appears to have provided moisture aditions'which approached the ideal for the production of ntaloupes. Plo -B C 1) i a u * o »  x J. J. • Application of Amount t Applied at each Irrigation ins. 2 3 3.6 A Table VIII increase up to of The Number of ap-lio-i . 4 3 6 -L ~  \^  J - •* * ^ V W V« . J. v <w* M M **«M w  <uv — -m  •» V •»-• ^  •— -- —  —  — -Amounts of Water Were Applied Water. Applied each Season 111S. 6 12 L° 24 shows that with 24 inc> les (4"x water, however, decreased w i most profil cost of water, it is will pay t c -able amount of value c apply plentiful and land Yield Tier plot 1  acr e 140 1920 192 1 1?2 2 Averag e lbs. lbs . lor . IDs . 87 10 1 10 4 97. 3 90 7 1 16 2 107. 7 124.3 11 3 13 0 129. 1 154 13 7 17 0 160. ; carrots the yield per acre u / t Average yield per acre. Actual Relativ e lbs. 7 „ 13,622 90. 3 13,078 100. 0 18,071 119. 9 22,442 148. 8 Average yield per acre inch of water Actual lbs. 2,272 1,237 1,040 933 Helb b1 1 lbs. 180.8 100.0 82.7 - 74.4 increased progressively v/ith each 6) in the amount of water applied. Th e yield ith each successive increase s in the amount of P ax acre water apt; water to apply depends, therefore, on the relat f land and cost of production. Wher e water is the mos only a small quantity of water over is limit t inch lied. Ions between expensive item a large area of land. IVher e water ed the most profitable procedure will be one v •h Lch involves le application of a relatively large quantity of water to a lall area of land. Wher e cost of production, other than the >plication of v/ater, is great it will be of advantage to work relatively small area of land and apply comparatively large lairtities of water. Wher e cost of applying the water is the Lrge item in the expense account it will be advantageous to •>e a large area of land and do as little irrigating as pos-Lble consistent with commercial yields. The germinating power of carrot seed was adversely affect I by planting immediately subsequent to heavy irrigations. le size and quality of the produce was inferior when only 6 ichea (2Mx 3) of v/ater was applied. Under the conditions of this experiment 12 inches (3"x 4) f water produced a satisfactory yield of good quality carrots -tdUJ-C A.O. * J . -i.«? ~i-«JL «a w  « v Amounts of ..ater Were Applied" Applications of Water Yield per plot 1  acr e Averag e yield Averag e yield T4~D~ pe r acre. pe r acre inch of v/ater. Amount 'Numbe r Amoun t Plot Applie d o f Ap- Applie d at each lie - eac h 192 0 192 1 1 9 22 Averag e Actua l 'Relativ e Actua l Relativ irri«3.tion ations Seaso n A 13 C D ins. 2 5 3.6 4 . 4 5 6 I n s • 0 12 18 24 lbs. 2 Q 80 53 34 lb s. 68 41 33 , lbs. 7 7 113 113 101 lb a. 38.0 78.O 74.3 71.7 U* *J O « 8,120 10,920 10,402 10,038 7. 74.4 100.0 93.3 91.9 , 1,333 910 378 418 % 148.7 100.0 < 43.9 Date Aug. 6 13 18 S e p . l o 13 18 21 Oct .16 Tota l As (3"x 4 ) P l o t A l b s . 5 2.75 8.25 i ; 29 i n d i e a of wa t • 1920 P l o t B " l b s . 19 2.50 20.50 34 80 t ed b y er du r i P l o t G  P l o t D lb s. l b s . 6.50 3.7 5 5 14.7 5 4 .50 2.2 5 39 33 .2 5 b5 3 4 t h e f i g u r e s p r ng t h e seaso n C o n d i t i o n . P l o t A l b s . 2 5 33 8 68 e s e n t e d b rough t 1921 P l o t B  P l o t l b s . 24 2 4 15 1 2 2 .  1 9 41 ^ i n Tabl e I X no i n c r e a s e t h i n P l o t D l b s . 21 -: 60 P l o t l b s 34 10 13 77 e a p p l i c a t i o n y i e l d 1922 A P l o t 3  P l o t G  P l o t i ) l b s . l b s . I D S . 48 2 0 1 4 59 6 4 5 1 26 2 9 113 "...,; • 10 1 of mor e tha n 1 2 i n c h e s p e r a c r e i n I92 O an d 1922 , >5 .le in 1^21 the highest acre yield was obtained by applying ,y 6  inches (2"x 3) of water. I n each year the greatest ild per acre inch of water was obtained v/ith an application only 6 iches (2"x 3) during the season. Th e yield was not atly reduced when more than 12 inches (jj"x 4) was applied, i the data included in Table X indicate that there was a .iceable postponement of the date of ripening where the larg-applications were made. .(her e corn is grown as a truck crop 1 ,s lengthening of the time required to bring the ears to ketable condition may be of considerable importance. Th e itponement of the date of maturity consequent upon unneces-lly heavy applications of water may mean the difference ween profit and loss in the price obtained for the product. In 1920 when the seed was planted immediately subsequent irrigation, the germination in Plots C and D was consider-y weaker than in Plots A and B. These results suggest that there is no justification for 'lying large amounts of water to sweet corn. Unde r the iditions of this experiment 12 inches (3"x 4) of water pro-.ed ample moisture to promote optimum development of ears table purposes. Table XI. Yield s Secured Prom Cucumbers (Davis Perfect) When Various Amounts of .Vater ftere Applied. Plot, A B C D Applica Amount Applied at each Irrigation ins. cl : 5.6 4 tion of Number of ap-plic-ations 5 4 5 h Water Yield per Amount Applied 192 0 192 1 each Season ins. 6 12 18 24 lbs. lbs . 117.25 159.50 256.75 265.50 554.00 215.00 406.75 284.50 plot 1  acre 140 1922 lbs. 220.50 296.00 552.75 299.50 Average lbs. 165.7 272.1 - , : > 565.4 Average yield per acre { bua l lbs. 25,205 58,091 41,149 50,879 Relative % 60.9 100.0 108.0 155.6 5 3 2 2 Ave per of 1 rage yield acre inch water. Actual Relative lbs ,868 ,174 ,286 ,120 i 121.8 100.0 72.0 66.8 • Date Ju ly 20 ? ? ?5 2? :'J.1S.1 =5 13 17 22 25 51 Sep.10 16 Table XI I 1920 . Da te s Whe n P l o t A  P l o t 3  P l o t C  P l o t D l b s l b s . -4.5O 10 2 IP .50 3° .3 0 R.50 4  6 2.75 2 9 l b s . l b s . 5 1.7 5 1.25 12.7 5 10 2 6 18 4  2 57 8 2 ?7 .2^ 4 7 Cucumb P l o t l b s 1 5 10 e r s (Davi s C o n d i t i o n . A • 11.50 -r 15 2C -16 L5 , 0 -1921 P l o t B l b a . 1.50 5 11 ^2 -,5 M 28 • -44 ; 4 .. -P e r f e c P l o t 11 1 0 3 -o p 18 2c -n z 27 ->8« *> C P i o t l b s . l .^O 2 0 / 8, -£7 25 >^ -55 51 4 2 -50 Reached M JJ P l o t A l b S . -2.50 7 r 25 25 14 p l -or. -a r k e t a b l e 1922 P l o t B l b s . -2 18.50 12.50 2;: 52 40 52 -1 1 0 --P l o t G l b s . -2.75 13 25 49 2 ; 2C 44 -154 P l o t D l b s . -4 .50 11 27 44 40 u 77 -152 --Viiilt'.V•! - •  ' T T T ; : in;Arii~ 1920 l a u i e ^VXJ . •  ^ u u u u u B t i ; Date Plo t A  Plo t B  Plo t G  Plot D Sept .21 24 28 Oct.2 5 14 Total l b s . l b s . 5-50 1.25 Si 4.50 4.75 117.25 Prom Tabl e where 2 4 inches 8.50 10.25 -*6 11 57 256.75 XI i t (4"x 6 p rogress ive ly a s smal l the othe r hand , p.ore v/a t p l ied d n l b s . 34 4.25 -32.75 5.50 5? 334 l b s . 32.25 11.25 3 31 5.25 106 406.75 1921 1922 ; P lo t A  Plo t 3  P lo t 0  Plo t D  P lo t A  P l o t 3  P lo t G  P lot u l b s . l b s . l b s . l b s . l b s . l b s . l b s . l b s . 25 5 2 4 9 5 2 • 159.50 263.5 0 21 5 2o 4 220.5 0 29 6 552.7 5 5??.5 0 i s apparen t t ha t th e g r e a t e s t y ie l d pe r ;  ere o f enei r oer s aa s secure d ) o f wate r wa s er amount s o f was g r e a t e s t er wa s used . A f a i r r ing t i e season , bu t where 1 appl ied durin g th e season . Th e acreag e y ie l d decrease d water wer e used . Th e yie l d pe r acr e inc h o f .vater , o n eas t wate r wa s appl ied , an d decrease d c o n s i s t e n t l y a s yie ld wa s secare d wher e onl y 0  inche s (2" x ~j)  o f / a t e r wa s up -the pe r oentage o f unmarketabl e produc e wa s l a rge r tha n wher e -59-ro water was used. Th e vines in Plot A were observed to wilt eely during the month of August and the yield was no doubt riously reduced by drought. Pro m the data presented in Table [ it appears that the application of comparatively large ounts of water had little effect on the length of time reouir to bring cucumbers to marketable condition. The sowing of cucumbers immediately subsequent to irrig-Lon had no apparent effect on the germinating power of the 2d. It is evident that the cucumber responded satisfactoril y larger amounts of water than proved desirable in the case the cantaloupes and corn. Unde r the conditions of this periment the cucumber seems to have justified the application 24 inches (4"x 6) of water. I t must not be forgotten, how-er, -that yield per acre inch of water is an important factor determining the economical application of irrigation water. xs Table XI shows that, over the three year period, Plot D educed an average of .50.879 IDS of cucumbers per acre, while ot B produced an average of only 38,091 lbs. Thi s would sear to indicate that the application of 24 inches (4"x 6) water to Plot D v/as justified. However , when it is consid-3d that the same 24 inches (4"x 6_) of water if applied to lble the acreage at the same rate as water v/as applied to 3t B (3"x 4) would have produced 76,182 (38,901 X 2) lbs of numbers, the advantage of the larger application is seen to questionable. Th e problem becomes one of the relations be-3en the cost of water, the rental value of land and the cost -60-producing the crop. Sinc e there is not sufficient water ailable at reasonable cost to irrigate all the agricultural nd in the Okanagan it is probable tha t more economical pro-ction will be achieved, if this water is applied over a mparatively large area, rather than by concentrating it on small fraction of the land which needs irrigation. Conseq -ntly it seems plausible to state that, although the yield cucumbers was increased when mere than 12 inches (3Hx 4) water was applied, yet it is questionable whether the in-case in yield was sufficiently great to justify the larger plications. Table ..vITI. Yield s Secured i^ rom rota toes (Jersey ftoyal; When Various Amounts of Water :f « /ipn 1 led. Applications of ..ate: Yield per riot 1  acr e i7er?; e yield 1 t'O' pe r acre Average yield per acre inch of water. Amount Numbe r Amoun t Applied o f Ap- Applie d Plot a t each plie - eac h 1?2 0 Irrigation ations Seaso n 1521 192 2 Averag e Actua l Relativ e Actual ^olativ "I 51 . ]  o s. l o o . I n s . l u c . 7 0 . 0 108. 0 302. 0 160. 0 22, 4 00 61 . 8 109.0 171. 0 497. 0 259. 0 36 ,26 0 100. 0 IO9.3 141. 0 445. 0 2^2 . 2 y 2 , ; 0 8 bo. T I63.O 144 . J  4.5^. 0 23.6 0 35 ,46 2 97 . 8 1 L 1 '. i V -'2 1 D 0 :' P 3.6 -.-J 4 5 t 0 12 18 24 l b s . I D S 2.733 123. 5 3,022 100. 0 3,HOG p ? . 8 1,478 30 . 9 T rc r t h r f i b r e s p r e s e n t e d i n Tabl e X I I I i t i s a p p a r e n t t h a t i n tw o y e a r s ou t o f t h e t h r e e t h e g r e a t e s t i o n pe r aor e o f p o t a t o e s wa s secure d whe n o- i l / 1 2 inche s (3 , ,x 4 ) o f v-'tter •--.- • cw.p l i e d. a p p l i c a t i o n O L ' a t c r L a c x o i ^ - of  t h i s amoun t i c t u a l l y r e s u l t e d i n a  de -c r e a s e i n y i e l d , e x c e p t i i 1920 . I n a l l c a se s b l e y i e l d ?e r s e r e inc h o f w a t e r dec rease d when mor e t h a n (  inche s (2" x 3 ) o f wate r wa s u s e d . Ther e wa s appa ren t ] : , n o c o n s i s t e n t r e l a t -ion betwee n th e oe r cen t o f onmarke tab l e t u h e r s an d th e rr.'^e  o f app ly in g w a t e r . Th e t a w l H v -62-the produce, however, was inferior where more than 12 ches (3"x 4) of water was applied. I n Plots C and i) the ps remained green and the tubers failed to ripen up as /tisfactorily as did those in riots A and 3. Under the conditions of this experiment 12 inches (>"x 4) water appeared to provide ample moisture to promote optimum velopment of tubers. I t seems logical to conclude that der Okanagan conditions there is nothing to be gained by plying large quantities of water to potatoes. Various Amggnta of Water Were Applle'l. P l o t A B D Appl i ca ' Appl ied a t eao h I r r i g a t i o n .. n  b . 2 , 3 . 6 4 biona o f Number of Ap -l i c -a t i  on s • ,i 3 6 Water Yie Amount Appl ied 192 0 each Season i n s . 6 12 18 ? l b s . 159.75 232.25 2 4 3 . , , ' 251.75 Id p e r p l o t 1  a c r e 1921 192 2 Ave n l b s. l b s . 1bs . 158.00 136.7 5 151 . 5 I38.OC 133.0 0 167. 7 229.50 159.7 5 210. 9 226.00 130 .5 0 202. 7 Average y i e l d p e r a c r e A - t u a l 1 23.485 29,529 28.385 R e l a t i v e '% <~Q.} 100.0 123 •0 120.9 Average y ie 1$ p e r a c r e i n h Of Water . A c t u a l l b s . 7. C J C 1 «  r^1 1 , 6 4 1 1 , 1 1 ; R e l a t j jr r 1 8 1 . ] 1:30.0 8 3 . 8 6 0 . 4 1 1 ) i > i 1 ( ; ' ! 1 i i •i i i s t I > 1 > -I ! ) } ) y i \ 1 -^ H J 1 3 rj ' CM CJ ax H ON rH o ON H 3 p o — c P o ''! P i H PH P o rH =1 P o — •p o Pi p . o i <3j P o H PM ^ P Q rH CH O -P o ' PM 33 P rH PH <$ += o rH CO p cd P 4 L _r; H * CO fl • 00 ^ H * (0 a f-i • CO H • CO •15 r I CO a • •JI ••'• • • __": • CO •Q rH » CO £3 H • -: rH OO NO iiA C— rH CM "A o o t— 'A Lf\ * . • c— NO NO r*> CM tf\ c -(-rH •y- c- CM *A L-A t rH rH e- NO rH st 1 j 1 1 CO J St 1 tr\ CM • UA •-'•• • -1 1". CM • o • LT\ ON H LT\ >S CM CM H 2 1 9 •M 0 <1 -i WT— •• i J o "1 1 CM CJ 1 t~* H 1 c-rH CM i rH O 1 'CM O 1 r,A c— 1 CM "A c— • ! O •J". » CM 1 •<\ OJ • r<A 1 CM 1 M-\ NO rH H ! 1 ; 1 '-A — H J "> — H r-O LC\ V o "A *> r<\ "A CM • ; H i ON H O -\ ^ ** --o "A * -O • • 0 i 1 1 1 :'• ••••: * cv » o A • CM i r\ CM rH 1 1 t i 1 I 1 1 1 1 1 1 :.• u> •> H •1 T o\ vO A CM i ! 1 : UA CM N 'A -. CJ r<A c ^H — C i H <* -N) H >'\ CM -. i— rH NO H -o . co CM H i H 1 \ rH t— — CM I rH r<A ' A rH ~ i : -CM > CO , OO '-' CM • A CM r-: r<\ -X r : <~. 1 c, CO en 1 I l I J 1 l l*A H >-<A CM . KA rH o "A > o rH NO rH pr\ rH •\ r. I 1920 1921 1922 Date P l o t A  P lo t B  P l o t G  P l o t 1 > P l o t A  P l o t 3  P l o t 0  p l o t D  P l o t A  P l o t B  P l o t G  P l o t v Ibi"; TosT.  Tos~.  Ths~.  l b s . l b s". l b s . l b s . l b s . l b s . l b s . l b s . Sep.16 7*3 0 1 0 7  7 .5 0 - r - - - - - -20 9.3 O 2 4 2 2 1 4 9  7  28.3 0 3 9 2  2  4  3 24 1 3 1 3 1 8 1 7 5 4 4 1 7 6 8 3 2 7 2 0 3 6 2 7 Oct . 2  4 .3 0 30 .7 3 19 .7 3 30.7 3 9 6  11 .2 3 19 .7 5 22.7 5 25 -  -  4.5 0 1 3 26 7.5 0 22.5 0 8 0 24.5 0 27 3 4 4 8 -  33.5 0 Total 159.7 5 232.25 243.50 251.75 13 8 13 8 229.5 0 22 6 136.7 5 13 3 159.7 5 130.5 0 From a survey of Table XIV it is apparent that the yield per acre did not justify the application of more than 18 inches (5.6'»x 5) of water to tomatoes. Quit e satisfactory yields were secured v/here a total of only 12 inches (3"x 4) °f water was applied. B y far the great-est yield per acre inch of water was obtained where a total of only 6 inches (2"x $)  o f water T r : w ! given. Tabl e Z7 is evidence that the application oJf more ,n 12 inches (3"x 4) of v/ater had no appreciable effect on i length of time required to bring the fruit to marketable idition. Th e plants in Plot A suffered visibly from drought 'ing the month of August. Some interesting observations were made with regard to the ivalence of physiological diseases of the tomato. I n order facilitate irrigation and. cultivation of the adjoining crop;. h tomato plant "/as pruned to a single stem and trained tc an dividual stake* Althoug h this method of culture has met with :at success in the coast regions of the Province it is appar-ily not adapted to Gkanarjan conditions. Th e extremes of iperature to which the fruit is subjected, owing to the fact it it is exposed to the full heat of the sun during the day, is held up off the ground so that it cools down rapidly at ;ht, seem to set up physiological disturbances in the cellu-• tissue. Eac h of the fruit was rendered unsalable eithe r "oi~ issom-end rot or oj  cracking . I t was observed that whereas s blossom-end rot decreased, the cracking increased where the 'ger applications of water were made. Thi s appears to indic-i that the prevalence of physiological diseases is intimately lociated with mcistrwre conditions in the soil, and suggests it these diseases may be largely controlled by maintaining >per conditions of soil moisture. As with cucumbers, the exact amount of v/ater which it is it profitable to apply to tomatoes can be calculated only by -67-)nsideration of the cost of water, rental value of land, t of production, and cost of applying water. Sinc e these bs vary with the districts and with each individual grower Ls impossible to make a general statement which will apply ill cases. Th e final interpretation of the results rests i the grov/er, who must apply them to his own local conditions 11 Temperature Records. No ad'tual records of soil temperature were kept in 1?20. '/ever, the fact that the application of relatively large mtities of water immediately previous to seeding of "beans, en, carrot s and cantalcwroes, seriously reduced the percenta-of germination in these crops, suggested that the water had shilling effect on the soil. Thi s contention is substaritiat-by the work of several American investigators. I n l^lO r/ers (31) of the Oregon Agricultural Station, made a study the effect of irrigation on soil temperature. H e found that rigation lowered ti e temperature of the surface soil in Ltivated plots as much as 4 deg. F. Th e investigations coa-sted by lev/is (24) in the Rogue River Valley, showed that the LI temperature might be reduced as much as 3 deg. J?, immed-tely following an irrigation. Harri s (20) in his work with 3 irrigation of sugar beets at Logan, Utah, found that irrig-Lng the land after the seed was sown and before it came up, luced the yield below that secured 'where no irrigation water S applied. In view of the results cf those soil temperature investi-tions conducted elsewhere, it was considered probable that e temperature of the soil in this experiment had been preciably lowered ~ov  the application of irrigation water, rthermore, it was conceived that such a lowering of the soil aperature might account, st least in part, for the postpone-it in the date of maturity of such heat-loving crops as corn il cantaloupes, which was observed to take place in the plots -69-I which the larger applications of water were made. Accordingly it was planned to keep accurate records of th€ ill temperature of each of the plots throughout the following •owing season. Suc h a procedure was not found to be possible i 1921, but in the summer of 19 22 considerable data relating ; soil temperature were secured. Unfortunately the special soil thermometers ordered for lis work did not arrive until after the crops were v/ell start-However, readings were taken of the soil temperature in ich of the plots, almost every day, during the latter half of ie growing season. The thermometers used have a brass point which was forced ito the soil to a depth of six inches (6") , so that the re-irds secured indicate the temperature of the soil six inches low the surface. I t is considered, therefore, that the fig-'es represent a fair average of the temperature conditions in ie upper foot or two of soil. Four thermometers were used, one in each plot, and when a lading was taken these thermometers were placed in the same :lative position in each plot. I n order to ensure that the icords taken gave an accurate representation of the temperat-'e conditions which existed in each plot the thermometers ire moved to a new location each time a reading was made. T o itermine the changes of temperature which took place in the ill during th e day, readings were made at 7 A.M., 12 Noon, id 6  P.M . The da i l y rang e i n temperatur e o f th e s o i l i n P lo t A ^ring th e mont h o f Augus t i s show n i n Tabl e A V I. Table X7I. Pail: ' Range of Soil Temperature In Plot A During August 1?22. ate 7  A.L'. 1 2 "Toon 6  '£ o-. 1 , 0 « J . 2 3 4 5 6 7 8 9 10 " 12 M 14 15 16 17 18 I 20 21 Z'd 72 72 73 73 72 — 66 68 65 68 - -__ 66 75 V 60 -64 6j5 62 60 5? • C 77 31 75 73 77 7o 73 72 71 - -- -67 SQ 74 72 — ~ 65 6? £1 80 84 - -— -— 78 30 78 7 1 - -— - -— - -80 78 71 - -- -bB 68 -71-Table X7I (Continued) Date .23 24 25 ^6 27 28 29 30 31 ;rage 7 A.M . 60 60 62 64 - -65 • - -67 63 65.9 12 Noo n 68 , 75 70 — 71 - -67 64 72.7 6 P.M . 67 -__ - -— 76 75 72 64 74.8 From the data incorporated in the Table IC7I it is apparent it, on an average, the soil in Plot A was about 9°F warmer 6 P.M. than was the case at 7 A.M., and that the temperature noon was about 2*F below that registered at 6 P.M. - With ight variations these relations between the records taken rning, noon -and night were observed to hold true for Plots B, Lnd D, and for the months June, July and August. The average daily temperature of the soil in each plot was ibably somewhere about midway between that registered at , L.M. and that observed at 6 P.M. - However, since the relation lip between the soil temperatures in the several plots was ind to be essentially the same at 7 A.M., 12 Noon and 6 P.M. is apparent that the data recorded at any one of these times fords a n a c c u r a t e i nd i ca t i o n o f th e r e l a t i v e temperatur e o f p s o i l i n eac h p l o t . Accordingly , t o avoi d unnecessar y o l i ca t i on , onl y thos e record s mad e a t 7  A.M . ar e include d subsequent t a b l e s . The temperatur e of * th e s o i l i s determine d l a r g e l y b y th e Qperature o f th e a i r abov e i t . "Rai n a l s o m a t e r i a l l y a f f ec t s I s o i l t e E  Mre . Cor : L n an y inves t i ga t i o n o f 3 inf luenc e o f I r r j jjatio n o n th e temperatur e o f th e s o i l , jount mus t b e t £ ~ f ter n r e change s du e t o r a i n f a l l L to f luc tua t ion s i n th e a  pheri c temperature * Th e f o l -ding t ab l e s show : th e s o i l temperatur e i n eac h p lo t a t 7  A.M . ) maximu m an d minimu m atmospheri c temperature ; an d th e r a i n -Ll, fo r eac h da y tha t record s wer e take n durin g June , Jul y I August . A  note i s a l s o appende d givin g th e date s whe n l iga t ion wa s p r a c t i c e t  r e o f th e wate r p l ied . I >" Table :i7II. >.•  -  ^.-.t-vr.- :f t r o:'.l in ,a::. Plot -  Jun o 1Q2" . t e S o i l P l o t A °P Terar e ra turf. S 7 P l o t i  P l o t G O p O-r p * 1 i :  0 t o- . » _'e ^ • i  r r * •  • ' a : : . 0 - i ior i c ,r<:s 3 a i n f a l 3 ;,. 1 n« 22 23 24 25 2b •27 2P 2? 30 rage 66 - -w7 — 66 72 72 — 72 70 .2 o ^ — 67 — 0 ' / 72 72 - -70 69 .8 0 0 - -o7 - -67 72 7C ---70 69.2 '_ 0 — o7 - -o7 71 70 - -6? 68.8 7C 7 . 7 ; 80 ?c 3u ?1 88 86 J^ 47 y . pi? .7 63 6 c >7 61 B. Irrigatio n wrter at a tenperature of 74° F was applied to all plots on June 22nd. It will be noted that the soil temperature rcjor3s pres-ted in Table XVII indicate that during the ten days subseq-nt to the iri'igation of all plots the average temperature of e soil, six inches below the surface was abrud 1° p lower in ot D than in Plot A. I t will be remenbered that water was plied to Plot A in two inch (2") applications, and that to ot i) 4 inches of water was applied at a tine. l.#r L . ..-'jpyil,'.'! -7-* I t appea r fro - ••-< • -i at& Rr. \ for* > if . >,:.: * 17: * 'ha* . *  e p l i c a t i o n o f v fc r ' i - e ar . •: v. J; I F. ; f -et>- r a 4 &  *  *• 7  <: • r'i"-.. ro : f •P t o a  s e l l t h e t '- . .rora*\ ; r < c- f •; • '•: i': h w*, ; - ' , * ? , h&d , ' i . ' veral days , n o a ; -p .-"<-<- 5 a;. 1' r**fr :.» : ) - «  •  r. a c i i *  e: .r «: rt tv . r e. the en- i o f a  wee k '."•"' . 4  < • *  !*:;« • * w "a* « • * vn r ?»rr ". ie i Iffever, t h e te-.T r era* .. r»- o f t'* c K  ' 1 . -;hich ha d rr-o t iv < i  2 ehes o f water , ha- i ri^c-r . V  ai : :..•..< : h a s ;*!* ' >^..v - *  - a t c f * . .0 11 wher e 4  incho E o f wate r ha d t-'-e.- j ; i v v , . A  * . /.on. . splanation o f t h i s r  he:v: •;,.•, ncn .  :-ui d a»:p«.a r '- < b< - for'.'-ec-.; . In-" om a  c o n s i d e r a t i o n o f 1.h e fac t r*-.a t to e evaporatio n l u e s e s uld l i k e l y b e g r e a t e r f r c . t v c p l o t r e o e i v i n j ; th e iar-'^ r • n t i t i e s o f w a t e r . I f e-;c h v.'er c th e cas e i t i e p r c c n h . e :at som e o f th e hoa t r e q u i r e d fo r v a - c r i . n a t i o n w  u l d h e ab -rbed fro m th e s o i l . I t i s a l s o p o s s i b l e tha t wher< > th e rger amount s o f wate r wer e appl ie d th e moistur e comer.t . ct ie s o i l wa s increase d t o euc h a n ex ten t a s t o chec k th e powe r the s o i l t o absor b an d t r a n s f e r heat , e laborat e i n v e e t i -i t ione b y Pat te n (28 ) hav e show n t h a t th e eas e wit h whic h lat i s transmit te d throug h s o i l i s c l o s e l y a s s o c i a t e d wi t h ie moistur e c o n t e n t . -7i5-Table XTEIT . t e m p e r a t u r e o f th e S o i l i n Eac h P l o t -  J u l y 1922 . S o i l Temperature s 7A.M . Atmospher i c R a i n f a l l Temperatures P l o t A  P l o t B  P l o t G  P l o t D  Max . Min . y 1 2 3 4 5 6 7 8 : 10 11 12 13 14 15 16 i 17 18 19 20 21 67 — — 68 67 1^7 08 72 72 ^ 68 — — --68 70 68 70 7, 72 70 87 64 --— 66 88 66 — — 68 71 72 66 64 68 __ 66 68 66 --68 71 72 60 64 1 : -?8 87 87 88 71 79 79 72 82 86 93 83 76 83 90 91 88 3^  81 60 .6 . 69 63 62 64 52 ., 1 • > 55 35 58 57 58 77 62 60 58 35 -76-Table X7III (Continued ) Atmospheric Soil Temperatures 7 A.LI. Temperatures . Rainfal l be Plo t A Plot B Plot C Plot D  Kax . Illn . °F. °1.  °7.  °T \ °¥~.  •¥".  Inches . f22 23 24 : 26 27 28 29 30 31 rage 68 o :: 71 68 6P 06 70 — 72 69.4 65 65 o? 65 >5 63 67 — 6? 67.5 62 Sj5 67 0 0 65 63 66 _.. 68 66.2 63 64 67 65 65 62 0 . - -71 63.? 70 77 ^> 81 81 76 83 84 8? ?1 58 48 53 60 > 56 56 60 o2 60 Irrigation water at a temperature of 62°F was applied to all plots on July 8th., and on July 19th water at a temp-erature of 679F was applied to Plots & , C and D. The data embodied in Table XVTII indicate that dvring the th of July the temperature of the soil in Plot i> was, on the rage, 3«58P lower than that registered at the same hour in t A. Thi s difference in temperature may be explained on the is of indirect loss of heat, as was suggested in  th e discus-n of the soil temperature records for June. -77-Another possible explanation is brought to mind by an imination of the soil temperature data secured before and fcer the application of irrigation water on July 19th. O n it date, v/ater at a temperature of 67°F was applied to Plots G and D. Previou s to the application of water the tempera-re of the soil in all plots at 7 A.M. was 72°F. A t the same XT on the following day the temperature of the soil in Plot bad dropped to 70°F, v/hile the thermometer in Plot i) register only 60°F. Sinc e no v/ater was applied to Plot A it is fair assume that the drop in temperature from 72°F to 70"F, corded in this plot was due to causes other than the applic-ion of irrigation water. Allowin g that the same modifying fluences had caused a drop of 2°F in the temperature of the il in Plot D, there is still a difference of 10°F to be counted for. I t seemed logical to infer that the application a relatively large quantity of v/ater at a temperature ^°F wer than that of the soil had exerted a direct chilling feet on the soil. Thi s contention was not supported, bow-er, by the data secured during the month of August. -r-fce g . l 2 3 4 5 6 7 8 9 10 11 12 13 \ I * M 16 17 18 19 21 Tab! So i l P l o t o n 72 72 73 73 72 - -68 ,.c -— - -66 73 63 60 - -64 63 62 V T Y rn ^ Hi . Temper a A PI0 1 B O" ' - . -70 71 68 69 __ 64 bo 67 67 - -- -66 73 62 60 — 63 63 62 j t  -, r ~ , n o r : 0 ' • • ' 68 7 1 7 1 70 70 — 39 - • • : • 66 • ' • ; »_ - -62 69 61 ; — 63 _ 62 L r e c  [ the S o i l -.'. j-.nn 1922 . 7 A.M . 0 n o t • n 67 7 1 7 1 70 — 39 62 63 63 — - -63 72 :-2 59 — 63 64 62 i n Eac h Atmos ?he ^i c Tempera tures D Max . 0 n / J -37 37 32 33 79 79 84 ; i 72 72 • 6 7 67 78 68 77 82 77 68 70 Min. 0 T 63 C4 64 '/ :.o 39 33 57 r 7 3o ; - - • 34 3 2 33 53 33 34 37 61 52 Ha-ii f a l l . 0 3 •35 . 1 0 •09 . 0 5 . 8 2 . 07 - i  / -ie J. 2 1 2 2 2? 20 25 26 27 2c 29 30 3 1 •rage !. I i t s G i l l o a ih« Th i th o • face it D . S o i l T P l o t A ° p • &o 5? 6o 6o 62 • 64 63 — 67 63 6 5 . 9 T a b l e 3 i i . p e r a t u r e s 7 P l o t fl op « 59 58 62 60 60 64 ; • — 66 62 6 4 . 6 P l o t • p 5S 37 60 60 60 60 ,2 - -63 61 6 3 . 3 XIX. ( C i i . 1 . . G P l o t D • F 5= 3R Si , . 58 60 -2 _« 60 61 6 3 . 2 o n t i n u e d ; A t m o s p h e r i c Te . p e r a t u r e s LI a x. u 72 n 3 79 32 n -p i 87 71 81 80 62 r r i g a t i o n IVate r a t a  t e m p e r a t u r e o f a n d D t i o n o f e d a t a on Aug . v ; a t e r 2nd an d 3 r d . I . in 0 32 30 77 34 y-36 60 &3 55 >? j 7 S3 0 ? and P l o t D I n c h e s . - 3 v/as a p p l i e d t o r e c e i v e d a n a t a  t e m p e r a t u r e o f 60° F o n A u g . l o t h an d i n c o r p o r a t e d f A u g u s t t h e t empe re , wa s a n a v e r a g e o f I t i s e v i d e n i n T a b l e XI X sho w t h t t u r e o f a b o u t 3 ° t , t h e r e f o r e , t h e s o i l P h i g h e r t h a t t h e s i x i n app a t d u r i n g t h e i n c h e s belov / t h e P l o t A  t h a n i n l i c a t i o n o f com -' -80-ratively large amounts of water had brought about a lowering the soil temperature. A  oritical examination of the records fore and after irrigation, however, does not reveal any rect relation between the temperature of the water applied d the temperature of the soil. Ther e was no significant ange in soil temperature subsequent to the irrigation of ots C and D on Aug. 2nd.' and 3rd. Followin g the application water to Plot D on Aug. l6th and 17th there was a uniform se in temperature of about 4°F in the soil of ail plots. is rise in soil temperature was probably closely associated th the rise in the maximum atmospheric temperature from 68*F Aug.15th to 82°F on Aug. 17th. It is interesting to note the effect on the soil temper-are of the .82" of rain which fell on Aug.19th. - At 7 A.M. Aug.19th the soil temperature in each plot was: Plot A 6.5*1?, ot B 63*P, Plot C 62°F, Plot D 64aF. A t the same hour on g. 20th the temperature of the soil in all plots was 62° F. From the foregoing Tables it is readily apparent that ligation did have an ap-nreciable effect on the soil tempera-re. Throughou t June, July and August the average temperature the soil in the plot which received 24 inches of water was Per than was the case in the plots which received less water. isolated cases the difference in temperature between the 11 in Plot D and that in Plot A was as great as 10°F; the srage difference throughout the season was just under 3°F. s soil in Plots B and C was intermediate in temperature tween that in jglots A and D. 1 > • i : w -81-This difference in temperature of the soil in heavily and ;htly irrigated plots might, conceivably be due to two main ses. I t seems logical to expect that the application of er at a temperature lower than that of the soil would exert irect cooling effect, and that this cooling effect would be ensified by an increase in the amount of water applied. In, the losses of water through evaporation and percolation Id undoubtedly be greater fro m the plots v/hich received the ger quantities of water. Wate r lost through percolation ;ht carry away, heat which it had absorbed from the soil, while seems altogether probable tha t some of the heat required to orize the evaporation losses was drawn from the soil. Th e a collected appear to substantiate, in the main, the center-n that the cooling effect of the larger applications was ef-ted through indirect means. Th e lower temperature registered the plots receiving the larger amounts of water appears to e been associated v/ith the increased soil moisture content of >se plots, rather than with the temperature of the water lied. Through whatever means the lowering of the soil was brought ut it is clear that the application of irrigation water was primary cause. I t is manifest, also that the application of cessively larger quantities of water was accompanied by a gressive lowering of the average soil temperature. Here , n, may be at least a partial explanation of the fact that the lication of unnecessarily large quantities of water materially tponed the date of maturity of such heat-loving crops as -82-)rn an d cantaloupes , an d seriousl y affecte d th e germinatin g mer o f beans , car ro ts , cor n an d cantaloupes . il Uolsture Records Although n o ac tua l s o i l r cistur< ^ V r Ligation s er < -i e 1920, s eve ra l importan t observat ion s r r e recorded . I t fa s served t h a t a s th e seaso n advance d i t becam e inc r as in^l ; f f i c u l t t o »e t th e s o i l i n H o t s Z  an d J  1  t s •  th e r c -r ibed quan t i t y 0 " v/ater , eve n -h e • r r i - a t i c n .va " r  L o _-- i er tw o o r t h r e e days . Plo t A  o n th e ct . o r hand , ab e >rbe d s quot a i n a  fev , hours . In orde r t o determin e th e d i s t r i b u t i o n i f o i s t -"< : et.'e < 1 rrows a f t e r var iou s amount s o f v/ate r " • i  bee n ap p ied , tr < ',c h B were du g t o a  dept h o f ^hC'C  f r e t , a-jros t eac : o f I  c o t s , twenty-fou r hour s a f t e r t h e t - i r d i r r i r a t i o n , A  unifor m s t r i b u t i o n o f r m i s t u re wa s foun d t u ex i s t i n a l l _  Lots e:: -pt Plo t A . I n t h i s p lo t t h e app l i ca t io n o f 2  inche s o f >.ate r i n t e r v a l s o f tv/ o week s ha d apparent l y fa i l e d t o thorough! ; Lsten th e s o i l betwee n furrows . Plot B  represente d th e happ y medium . Th e s o i l absorbe d 3 app l i c a t i o n o f 3  inche s o f wate r qui t e readi l . " i n a n eleve n xr day . Furthermor e th e 3  inc h app l i ca t io n appeare d t o b e rge enoug h t o ensur e a  unifor m d i s t r i b u t i o n o i moistur e be -Ben th e i r r i g a t i o n furrows . A t n o tim e betwee n i r r i t a t i o n s re th e p l an t s i n Plo t 3  observe d t o b e suf fer in g fro m lac! : mois tu re . From thes e observat ion s i t seeme d log i ca l t o i i ^ r r t ha t th th e s o i l an d c l imat i c condi t ion s unde r whic h th e exper i -i t wa s conducted , an d wher e approve d method s o f i r r i g a t i o n rrning wer e followed , th e app l i ca t io n o f ; > inche s o f wate r -34- * . fortnightly intervals durin? the grovrin? -season, was 'icient to maintain conditions of soil uoi3ture favourable ;he growth of nany of our cordon truck ero-cs. 'fhi s obser-on is substantially in agreement v:ith the results obtained 'owers (31) at ./est Star-ton, Oregon, in 1911. xh e soil at i Stayton is a gravelly loam. I t v;as found that on this 18 of soil a p inch application at intervals of fifteen 1 was about the best amount ana frequency of irrigation for ivated crox>s. » il Moisture Observations 1921» No actual soil moisture determinations were made in 1921, t the field observations substantiated in the main, the notes de in 1920. I t was found, however, that in 1?21 a uniform stribution of v/ater was secured between furrows three feet art even when only 2 inches of v/ater was applied at an appli-tion. Thi s is probably explained by a consideration of the ct that the improved cultural methods adopted in the second ar of the experiment effectually stored a good deal of the tural v/inter precipitation in the soil and subsoil. Owin g the presence of this reserve supply of moisture it is likely at the soil at no time dried out as completely as was the se in the Spring of 1920. Consequentl y a uniform distrib-Lon of soil moisture might well have been maintained by a aller application of v/ater in 1?21, than was the case in the svious year. Th e difficulty of getting Plots G and D to sorb their allotted quota of water v/as again experienced in 21. Owin g to the impossibility of measuring v/ater accurately night, irrigation v/as carried on in the daytime only. A jord waa kept of the actual time which was required to apply jh irrigation. Tabl e XX shows for each plot the dates when ter was applied; the amount of v/ater applied; and the time luired to apply the v/ater. Plot A Plo t B Plo t G Plo t D Dates v/hen V/ater was Applied June 1 & 2 " 13 & 16 " 29 & 30 July 14,15 & " 30 , 31 & Aug. 13, 16 & Amount of Water Applied Inches 2 ?. 2 16 1 17 Time Amoun t required o f to apply Water v/ater Applie d Hours 4 7i 7-3 ---Inches y 3 3 3 --Time required to apply V/ater Hours 6 104 10* 104 --Amount Tim e of require d Water t o apply Applied v/ate r Inches Hour s 3.6 3.6 3.6 3-6 3-6 -?i+6-i$£ ?^+7=l6£ 9+ 8= 9+9+8=26 9+948-26 -Amount Tim e of require d Water t o apply Applied v/ater . Inches 4 4 4 4 4 4 Hours 9i*8=i7i 9$ *10sl9i ?i+lo=l9i 9+10+10=29 10fl0+13=33 10*-10 + 1 =^33 Total 6  1 9 1 2 37| - 1 8 10 1 •  2 4 l^ lf c -87-Table XX shov;s clearly that the time required to apply er increase! as larger amounts were used. Furthermore , an rease in the quantity of water applied resulted in a greater a proportional increase in the time required to apply it. s when 12 inches (3"X 4) were applied the time required was hours, but when 24 inches (4"x 6) was given, ljJlj hours s required to apply it. I n other words a doubling of the otity of water applied resulted in the quadrupling of the 5 required for application. It is readily apparent that the longer the time required apply an irrigation the greater is the opportunity for loss noisture through evaporation. Consequentl y it is obvious fc it is advisable to apply water only in such quantities as soil can take up fairly quickly. I n order that enough wat-to supply the needs of plants over the period between irrig-Dns may be absorbed in a relatively short time, it is of the Dst importance that the soil be maintained in frood physical lit ion. Again the time required to apply water increased as the son advanced. Thus , when the first application of four ies v/as made to Plot D on June 1st aad 2nd. , only 17* hours 3 required to apply the water, while when the final applic-Dn of four inches was made on August 1.5th, 16th and 17th it necessary to run the water for 33 hours in order to get the L to take up the allotted quantity of water. It v/as thought that this increase in the time required to Ly v/ater as the season advanced might be explained as a p.- - T - ~ -88-It either of a diminution in the power of the soil to absorb r due to impairment of physical condition, or on the grounds the previous irrigations had had a cumulative effect on the nt of soil moisture. I t seemed quite conceivable that a Lderable quantity of the v/ater applied at one irrigation t still he present in the soil at the time the next irrig-1 was made. I t also seemed possible that the reduction of lepth of cultivation after the crops had reached a certain 2 of development might have resulted in a diminution of the p of the soil to absorb moisture rapidly. I n order to Ln further light on this question it was decided to make .-atory determinations of the moisture content of the soil irious times during the growing season.of 1922. -8 9-,1 Moisture Observations 1922. It was planned to cake extensive moisture determinations 'ing the irrigation season of 1922. Unfortunatel y the lipment necessary t o make these determinations did not arrive time for uee before the crops were planted. Soi l samples •e colleoted, however, during the growing season, and a oom-ite determination was made of the moisture conte.it of the 1 in each plot at the close of the growing season. Th e lulte of these moisture determinations are presented in iular form. Considerable care was exercised with a view to ensuring i accuracy of the data embodied in the tables which follow. 1 samples were obtained with the aid of a small post-hole fur. I n order to ensure that the determinations were iresentative of average conditions a large number of borings i made in each plot. Separat e samples were taken of each t inches of soil down to a depth of three feet. The hygroscopic coefficient is a measure of the percentage moisture by weight v/hich a thoroughly dried soil will absorb in exposed to a saturated atmosphere at a standard temperatur< order to ascertain the value of this coefficient for the 1 on v/hich this experiment was carried out, the soil samples itioned above were dried to constant v/eight by heating in electric oven, which v/as so regulated as to maintain the iperature betv/een 9.5°C and 100°C. Te n grammes of each sample •e then weighed out and placed in a saturated atmosphere ntained at a temperature of 60*P. Afte r allowing the soil -?0-! stand in this atmosphere until no more moisture v/as taken i the weight v/as again recorded; the increase in weight rep-isented the hygroscopic moisture acquired by the soil. Thi s 'termination v/as thoroughly checked by repeating the above •ocedure five times for eac h plot, and averaging the results, iioh were then expressed in percentage of the dry weight of e soil. The wilting coefficient was calcultaed from the hygros-pic coefficient with the aid of the formula worked out by •iggs (4) : Wilting coefficient - hygroscopic coefficient. a . ^ The wilting coefficient is an index of the percentage of isture contained by the soil v/hen plants undergo permanen t lting. The field capacity represents the maximum percentage of isture v/hich the soil cau retain against gravity under free ainage conditions. I t was estimated by making determinations the moisture content of the soil forty-eight hours after avy applications of irrigation water had been made. The total capacity indicates th e percentage of water the il can hold when completely saturated, that is to say, v/hen e entire pore space is occupied by water. For the -ourpose of estimating the total water capacity, 1 pore space of the soil, a small metal container about 12 cm. diameter, and having a perforated bottom was used. A  circle thin filter paper, cut to fit the container, was wetted and 3 i n s i d e , :n T; Buperfluou s wate r bein g wipe d away . A  hundre d mines o f s o i l wa s the n ca re fu l l y place d o n th e f i l t e r paper , depth o f th e s o i l whe n sprea d oa t ove r th e bas e o f th e t a i n e r bein g aooa t 1  cm . L  not e r : s -sd d o f th e GO'-"0ine d ght o f th e conta ine r an d th e s o i l . ih e containe r wa s the n pended eve r a  dis h ~ f d i s t i l l e d water , s o tha t th e <w-.te r od abou t 1  :i:.m . a'jov e th e lowe r t^rfoc e o f t'n o s o i l ins id e box. fh e dis h was  covere d ove r t o preven t evaporat ion . about h e If a n hour ' s xi~. e th e s o i l ha d absorbe d o i l th e wat -p o s s i b l e , whe n th e cO i tu rner .--i t l i f t e d abov e th e .rate r r  JC o red t o dr& n fo r s  fe w minutes , of fe r whic h th e exces s er c l ing in g t o on e ,nde r acr.e^e  "" , ~ /ipc u a-a y an d th e le areweighed . Th e increas e i n r ei^ct represente d th e t o t a l er capaci t y o r cor e spac e an d v/a s ex . rcssed i n percentag e the dr y . e i g h t o f th e s o i l . Th e dat a show n i n Tabl e XZ I resent th e average s o f a  la rg e numbe r o f determinations * „92-ter Holding Capacity of Soil in Per Gent of Dry Weight. Experiments conducted by Hilgard (21) suggest that the Ll moisture condition most favourable to crop growth exists 3n between 40fo and (>0%  of the pore space is occupied by water ting on this assumption the optimum moisture content was rked out from the total capacity as Table XXI shows, in per-itage of the dry weight of the soil: the hygroscopic coef-;ient, the wilting coefficient, the field capacity, the total Dacity and the optimum moisture content of each foot of the aer three feet of the soil on which this experiment was con-;ted. Table XXI. ,/ate r Holding Capacity of Soil In Percentage of JJry Weight. 3th Hygroscopi c Jiltin g Fiel d Tota l Optimu m Coefficient Coefficien t Capacit y Capacit y Conten t set L • : 'o 1.82 1.80 1.37 % 2.68 2.65 2 .01 ,o / o / » 17-1? 35. 0 14. 0 -  21. 0 16.88 32. 5 13. 0 -  19. 5 14.60 29. 0 11. 5 -  17. 3 >rage 1.6 6 2.45 16.22 52 . 2 12 . 19.3 It is considered tha t the data presented in Table XXI are 'thy of a somewhat detailed examination. I t will be observed it in the first three feet of soil the amount of moisture .ch is not availaole for plant use, i.e. the percentage below i wilting point, is slightly less than 2.5V°- Th e average - _ _ _ _ — , _ — ,mum f i e l d capaci t y o f th e uppe r f - re e fee t c f s o i l i s ; ove r 16/ 1 fr o „  whic h i t i s apparen t t ha t th e ar c n t o f tture a v a i l a o l e fo r p lan t v.s e '  .ic h ca n c e s tore d i n th e ir th re e fee t o f t " i s s o i l i s onl y v . cu t lp.?\. The t o t a l wate r c a - a c i t y i s j u s t abou t doubl e t 1 e  f i e l d i c i ty , whic h r.ean s t'.i- t th e highe r lirt.i t o f th e cptir.ru : r.ci c t conten t est imate d b y :iil^ar d (21 / a t oC,' , o f th e por e ---ac e never b e reache d wit h t h i s s o i l , s o I o n ; a s tr.er e i s fre e nage. Consequentl y unde r f i e l d condi t ions , ther e i s l i t t l e , my, dange r o f t h i s s o i l becorain g to o .ve t fo r s a t i s f a c t o r y it growth . Ther e i s , however , a  ver , r e a l dange r c f l o s in g ir throug h pe rco la t io n dow n belo w reac h o f p lan t r o o t s . -<H-ter Holding Capacity of Soil in Inches The significance of these moisture determinations will Dbably be more readily appreciated by the practical irrigat-if the percentage of moisture is expressed as depth of water 3r the soil surface. I n Table ZZII tha above data have been lverted to inches of water, so that they may be compared reotly with rainfall and applications of irrigation water. Table XXII» .;ate r ridding Capacity of Soil in Inches. )th Hygroscopi c Wiltin g Fiel d Capacity Poin t Capacit y Total Optimu m Capacity Conten t jet 1 2 3 inches • 3  • 32 .25 inches incne s inche s Inche s .48 3.0 ? 6.^ 0 2. 5 - 3.8 .47 3.0 3 3.3 3 2. 4 - 5.5 .36 2.6 2 3.2 2 2. 1 - 3.2 lal .90 1.31 8.74 17.37 7. 0 - 10.3 A survey of Table XXII brings to light the fact that in the r three feet of the soil on which this experiment was car-out there is always about 1.3 inches of water which is not dlable for plant use. Th e amount of moisture which the same th of soil can retain against the pull of gravity where there free drainage is about 8.7 inches. Th e quantity of water ilable for plant use which can be stored in the upper three t of soil is the difference between these two figures, or roximately 7«4 inches. I n the irrigation of crops, the root : .. vi rstem of which does not penetrate oelov three feet, it is ivious that even should the moisture in the uo-ner three feet f soil be reduced to the wi_ting point, it would, oe folly to )ply more than 7«4 inches of water at one ap-olication. Theo r ;ically the optimum moisture content of toe upper three feet t this soil ranges between 7 and 10.5 inches, hut actually fch wage is much carrower. ?or , as has already oeen oointed out, le maximum field capacity is only about 8.7 inches . Lnde r ich conditions it would seeji. that the aim of the gro 'er shoul ; to maintain the moisture content of the up-oer three feet of )il somew iere between 7*0 and 8.7 inches. I t is oovious xhat lis can only be accom.jlisned by applying Water at the rate of )t more than 2 inches per application as often as the plants 3duce the amount of w ter in the soil to the 7 inch limit. Lth this knowledge of the noisture holding capacity of the )il it is no»7 possible to proceed to a cribical exai ination C the moisture conditions which actually existed in the sev-pal plots at various times during the growing season. -?6-Lsture Content of Upper Foot of Soil During growing Season. Table XXIII shows the moisture content of the upper foot soil in each plot 4§ ^Ours after the 2nd, 3rd, 4th, 3th, and lal irrigations. I t will be remembered that Plot A was irri-fced three times, Plot B four times, Plot G five times and )t D six times during the season. I t will also be recalled it at each irrigation Plot A received 2 inches, Plot B 3 »hea and Plot C 3.6 inches and Plot D 4 inches of water* Table XXIII. Moistur e Content of First Foot of Soil at Various Pates During Growing Season. Date Plo t 1 Plo t B Plo t G Plo t D le 24th - 48 hrs. after 2nd I.9 3 2.1 2 2.6 0 2.6 1 ligation of all plots. Ly ?th - 48 hrs. after 3rd 2.3 8 2.6 8 2.? 4 3.0 3 ligation of all plots. Ly 22nd - 48 hrs. after 4th 1.4 3 2.7 2 2.9 8 3.0 8 ligation of Plots B,C & D ?.2nd - 48 hrs. after 3th .8 8 I.9 0 2.8 8 3.0 2 ligation of plots G & D 5.21st - 48 hrs after final 1.2 4 2.3 2 3^0 3 3«0 9 rigation of plot D. The data contained in Table XXIII were arrived at in much i same way as the figures for field moisture capacity includ-in Table XXII. Sample s of the first foot of soil in each it were collected with the aid of a soil augur. I n order to fare that the soil samples were representative of the average .1 moisture content of each plot an equal number of borings -97-sre made "between each two rows of vegetables. Furthermor e lese borings were made midway between the irrigation furrow id the row of vegetables. Th e soil from these borings was len thoroughly mixed and a determination made of the total isture, both hygroscopic and capillary, which was contained i the composite sample. Thi s moisture content was then ex-•essed in inches to facilitate ready comparison with rainfall id applications of irrigation water. A careful scrutiny of Table XXIII brings to light several ,cts worthy of note. Althoug h only 2 inches of water was plied to Plot A on July 6th the amount of water in the first ot of soil on July °th was almost half an inch more than was e case on June 24th. Thi s is direct evidence that in spite ' the losses of water due to evaporation, transpiration and ssibly percolation, the 2 inch application of water received Plot B early in the season had, at least for the time being, cumulative influence on the soil moisture content. Thi s mulative effect of successive irrigations is more strikingly parent in the plots receiving the larger applications of ter - thus the moisture content of the upper three feet of il in Plot D increased from 2.61 inches on June 24th to J.0.5 ches on July 9th. A s soon as the t>oint of maximum field pacity v/as reached, however, there was no further accumulat-n of moisture in the upper foot of soil even where large plications of water were made. Thu s it will be noted that e fisrures showinc the moisture content of the first foot of il in Plot D, 2«t Hours after the 4th and 5th and 6th irrig--5C-ions indicate that there was no appreciable accumulation of isture after July 9th. A comparison of the actual moisture content of the plots th the optimum content shown in Table XXII indicates that on ly 9th the Lloisture condition of the first foot of soil in all. Dts was favourable to plant growthi Fo r on that date the Lsture content of the first foot of soil in each plot was Dve the lower optimum limit of 2.3  inches . I n Plot A, which 3eived its final irrigation on July 6th the moisture content the first foot of soil had fallen to 1.4.5 inches on July ad and to .88 inches on Aug. 2nd. I t is noteworthy that even Aug.2nd the moisture in the upper foot of soil in Plot A 3 still considerably above the theoretical wilting point. the field, however, serious wilting of crops was observed in Ls plot during August. Thi s observation can no doubt be ex-iined as the result of low atmospheric humidity. I n Plot B, Lch received its final irrigation on July 22nd, the moisture Itent of the upper foot of soil had fallen below the optimum nit by Aug. 2nd, but was still considerably above the theor-Lcal wilting point. N o appreciable amount of wilting of )ps was observed in this plot at any time during the season. )t C received its last irrigation on Aug.2nd. I t is impoS-)le to say whether, in the ordinary course of events, this )t would have shown a reduction of moisture content below the bimum for the upper foot of soil at any time during the re-Lnder of the season, for between Aug. 2nd and Aug.21st. there 3 an unusually heavy natural precipitation, over l.jj inches : rain Toeing recorded. Thi s rainfall also accounts for the .se in moisture content of all plots indicated by the deter-.nations made on Aug.21st. The most striking fact brought out by the data included t Table XXIII Is that successive irrigations, given at irtnightly intervals, did have a marked cumulative effect on ie moisture content of the upper foot of soil, even in the .ot to which water was applied at the rate of only 2 inches ir application. Thi s accumulation of moisture took place in dte of the losses of water through evaporation, transpirat->n and percolation, './her e more than J inches of water was •plied every two weeks, however, the limit beyond which .rther accumulation became impossible was soon reached. Thi s mit was determined ~oy  the field moisture capacity of the soil dch was in turn dependent upon the power of the soil to re-,in moisture against the pull of gravity. I t seems probable, lerefore, that the increased difficulty experienced in get-ng the soil in Plots G and D to take up the alloted quantity water as the season advanced was the result largely of an cumulation of moisture in the soil, but may also have been .e, to some extent, to a diminution of the power of the soil absorb and retain water. -100-.ature Content of Soil Before and After Irrigation. The conmarative moisture content of the upper three feet soil in Plots C and D before and after the 5th irrigation of je plots is shown in Table XJQ7. Thi s irrigation was given Lugust 3rd. and 4t>. Th e soil s^ r>-les from which the noist-determinations were made were taken on August 2nd and Sth. - Table XXIV.  lloistur e Content of Soil Before ate eet 1 2 3 tal and After Fifth Plot Before inches 2.06 2.27 2.4J 6.76 Irrigation "\ After inches 2.38 2.80 2.>6 8.24 of Plots C and v Plot 3efore inches 2.24 2.j58 2.56 7-18 D mm After inches 3.02 3.00 2.b2 8.64 The figures in Table XXIV include both hygroscopic and t illary moisture. Car e was taken to make sure that the soil iples from which the data were secured represented the aver-1 soil moisture content of each plot. A n equal number of rings were made between each irrigation furrow and the rov; of jetables on either side of it. Th e earth from the first foot each of these oorings was thoroughly mixed and a determinat-1 made of the moisture in the composite sample. Similarl y i earth from the second foot of each of the borings was mixed aether and a composite sample secured. Th e third foot of soil s treated in identically the same manner before being taken -101-the laboratory, where the moisture content was ascertained. Prom an examination of the data embodied in Table XXIV it apparent that just previous to the fifth irrigation of Plots nd i), the soil in these plots already contained quite a ge amount of moisture, in fact, by comparing the figures in above table with those set forth in Table XXII it is evid-that these plots were not at that time actually in any at need of irrigation. Althoug h the moisture content of the er three feet of soil in Plot G v/as just below the lower imum limit of 7 inches it is doubtful whether the practical 'igator would consider it advisable to apply more water until amount of moisture in the soil had been still further re-:ed. Theoretically It might seem of advantage to maintain the .sture content always above the lower optimum limit, but in ;ual practice it is often found more satisfactory to wait un-i the moisture supply has been depleted almost to the point jre plants begin to wilt before making additional applicat-is. Th e economy of such procedure in the present instance i be readily comprehended by a study of the results which Llowed the application of water when the soil v/as already Lrly well supplied. O n August 2nd the upper three feet of 11 in Plot D contained 7.18 inches of water* O n August 3rd 1 4th 4 inches of water were applied to this plot. O n August b the amount of water retained in the upper three feet of il was found to be 8.64 Inches. Pro m which it is apparent at of the 4 inches of water applied less than 1.5 inches v/as 102-ained where It could oe utilised by plants having s root tern which did not penetrate deeper than three feet. Th e er 2.5 inches had been lost either through evaporation, nspiration or percolation. Whe n it is recalled that the max m field moisture capacity of the upper three feet of this 1 v/as found to be only about ?.7 inches it is oovicus tnat, er the circumstances, such a lots .as inevitable. Lluc h tr.e e results followed the application of water to Plot 0 on •. ^rd and 4th. Previou s to the 5th irrigation this pxot tained, in the first t':ree feet of soil, 0.76 inches of wat-Forty-eight hours after t-.e arplicL tij.i of 5.6 inches of er, the urper three feet of soil were found to have a moist-content of 8.24 inches. Almos t 2 inches of the water ap-ed v/as unaccounted for. I t is very evident that under the 1 conditions of this experiment the application of more than nches of wcter oefore the soil moisture supply had been re-ied oelow the optimum limit for plant growth, v/as a most iteful practice. O f course it must be remembered that in the 'igation of plants the roots of which penetrate to a greater ith than three feet, slightly larger applications Might be stified. Th e essential point appears to be that, with a soil which the maximum field capacity is but little above the lov/ limit of the optimum moisture content, it is wasteful to )ly large qvia.itities of water until the soil moisture has m reduce d consideraoly below the optimum ran^e. Th e results ssented in Table 2LHV suggest that under conditions similar those encountered in the ce-rryin? out of this experiment it -103-ld c e T "ell t o " Tait v.nti l t i e - .cistrr e con-ea t o f c': e r ^ e r ee fee t o f s o i l Iri d Les i reduce - t o acor x 3  inche s ar J a t o ap-pl " a a i r r i ZH.  iioi; o f voc^ t ;  inches . •i ilia -104-, .sture Content of Soil at Close of Growing Season. Table XXV shows, for the upper three feet of each plot, » moisture content at the close of the growing season: Table XXV. I  oisture Content of Soil At Close of Growing Season - September ;>lst. Depth Plo t A rio t 3 Plo t C Plo t j) feet inche s inche s inche s inche s 1 .9 6 1.6 1 2.1 5 2.1 4 2 1.0 5 2.C- 1 20 1 2.4 7 J 1.1 8 2.0 7 2.5 p 2.o 2 Dotal 3.1 9 5.t> 9 o.9 9 7.2 3 The data set forth in tne above Tabic -er e secured by fcermining the amount of moisture in soil samples collected on >t.>l8t. Thes e samples v/ere cotained in much the seme manner those used to ascertain the moisture content of the soil in >ts C and 1),  oefor e and after irrigation. I n order to ensure It the samples were representative of tne average soil moist-j content of eacn plot, an equal number of borings were made tween eaoh two rows of vegetaoles. Th e soil from t :ese tor-58 was then thoroughly mixed and a determination made of the Lsture in the composite sample. Separat e determinations were lie lor each foot of soil down to a depth of three feet. Proa a survey of the data presented in Table XXV it is Ldent that at the close of the growing season tnere was still considerable amount of moisture in the upper three feet of \.l. I n faot, in plots C and 1), the moisture content was stii: -10^-,hin the optimum range for the promotion of plant growth. i importance of this fact, from the standpoint of moisture serration, will be readily recognized v/hen it is recalled ,t the field moisture capacity of the upper three feet of s soil was found to be only aoout 8.7 inches, ^fte r the ps had completed their season's growth the upper three feet soil in Plot 1) stil  contained 7.2^ inches of water. I t is cnce apparent that not ..ore than 1.5 incnes of winter precip-tion could be stored in the upper three feet of this plot. rain or snowfall in e :cess of this amount must inevitably lost, through percolation, evaporation or run off. It is probable t at the greatest loss would take place ough percolation, with accompanying harmful effects due to sing of the general level of the ground water, leaching out plant nutrients a.,d waterlogging of lands in the lower lying ticns of the district. I n Plot A on t.ie other hand there was D in the upper three feet of soil for the storage of 5.5 bee of winter precipitation, while in Plot 3 the available rage capacity wae about > inches. Sinc e one of the basic aciplee of successful irrigation farming is the conservation economic utilization of the natural precipitation it is S.0U8 that any irrigation practice r/hich precludes such action Inefficient and undesiraule. Consequentl y it is evident that Br the conditions of this experiment the application of more 11 12 inches of water during the season was ill advised in t it brought aoout a condition of soil moisture which prevent' the conservation of t .e natural winter precipitation. -106-From the foregoing discussion of Soil Koisture Cbservat -s it appears logical to conclude that with soil aiid cultural ditions similar to 'chose under rhic h this experiment .?as ducted it is v/astefui ;xd inefficient to apply r„ore than nches of v/ater at a time. rurther?.ore , under such condit-s it is disadvantage-us and uneconomical, fro;a the sta^d-nt of moisture conservation, to apply nose  tha n 12 inches x 4) of water during the season. 107-Although this experiment has been conducted on a compara-rely small scale, and although the records extend over a 'iod of three years only, it is nevertheless considered just-.able and advisable that a brief summary of the results be apiled. Th e statements v/hioh follow are based on the forc-ing Tables of experimental results: the y also embody field nervations made during the growing season. The highest yield per acre was obtained by applying 12 inches (J wx 4) of water to corn, potatoes and cantaloupes; 18 inches (j>.6"x 5) to beans and tomatoes; and 24 inches (4"x 6) to cabbages, carrots and cucumbers. The highest yield per acre inch of water was obtained, with each of the crops under test, v/here a total of only 6 inches (2"x ~j>) of water was applied during the season. Applications of 3,6 inches and 4 inches of water immed-iately previous to seeding noticeably reduced the percenta-ge of germination below that secured v/here smaller amounts of water were applied. Th e injurious effect of large quantit-ies of v/ater applied just before seeding was especially marked v/ith corn, beans and cantaloupes. Serious wilting of crops was observed during the month of August in the plot which received only 6 inches (2"x <j) of water during the season. I n accordance with the pre-arranged plan of irrigation this quantity of v/ater had all been applied by July 1st. -108-The aoolioation of 3 inches of water at fortnightly int-ervals v/a*- sufficient to promote satisfactory growth in all crops under test. The application of 24 Inches (4nx b) of water during the season caosed cro~>s sucn as corn and cantaloupes to nature as aiuch as fourteen d& ra later then v;as the case where a seasonal .  o-iicctioi of only 6 inches (2''s: j>) .70s 1 ,ade. An incresce in t >e 31 ount of ./ater apolied v/fs acconoan-ied by a decrease in the percentage of blossom-end rob of the tomato. The application of large qut itities of ;ate r appeared to induce cr-c.i o i the tomato. Where a total of 2^ inchee (4"3 C oj OL water was a'o-olied during the seasoi th e average oei : ?er^ tu.re of the soil, six inches belov, the surface, a s about 3 ? lower tnan was found to be the oase r/here only 6 inches (2"x 5) °f water was the seasonal quota applied to bhe soil. Application of p  inches ox /.aber c^ a time 5av e a unif-orm distribution of moisture oet ieea furrow s three feet apart. Thi s was not always found to se the ca^e where 2 inches of water was applied. The soil, although in eiccellenx physicrl condition, did not absorb more t _c • • J a nones of nte r in an eleven hour day. The application of 5.6 inches and 4 inches of '-ater at fortnightly intervals resulted i n an unnecessary loss of irrigation water. -109-;.'he.n 18 inches (^ .6"ic 5) and 24 inches (4":c 6) of water vac applied durine; the season the moisture content of the upper three feet of soil, at the close of the growing season, waa such ss to prevent the stora5e, in that depth oi soil, of any out a small fraction of the natural winter orecioitation. -110-iCTOHS '.7EI0H i!AY EL7H,  IlIEILEyCZI) fiE RESULTS Qg THIS EAPERILEEIT It is considered advisable that brief mention be made in his report of some of the more important factors, otherr than application of irrigation water, v/hich may have exerted a erial influence on the results secured from this experiment, is believed that these factors may be most advantageously cussed under the four general headings: Climate, doil, Gultur-[viethods and Experimental Technique. luence of Climate on Results of this Experiment. As has been previously explained, the climatic conditions erienced at Summerland are midway between those encountered the northern and Southern extremities of the /alley. Fo r s reason it is readily apparent that results secured at the merland Station can be considered to apply, with but slight ification, to the bulk of the irrigated land in the Valley. In order to facilitate such necessary modifications, and order that the results of this experiment may be the more dily compared with the results secured from experiments con-ted elsewhere it is deemed expedient to present a statement the climatic conditions v/hich prevailed while the experiment in progress. Furthermore , it is recognized that any attempt an interpretation of the results of this experiment should :e into account the possible influence of seasonal differences temperature, rainfall, sunshine etc. Fo r this reason it is sidered imperative that a section of this report be devoted - I l l -t s tud y o f rreathe r cond i t i ons . lOroloj ioal record s seov.re d a t th e Surorerlan i i t a t i c r : i . . r i : ), 19-2 1 an d 1?22 , -.a s oe s c ; ; i l e l . Zhes e record s .r e s s : ih i n t a u. 1 r  : ' : : . an: ! ar e c o : . .re ' . i c fa r a ^ ~ o s s i : l 3 ' i v rious -aexeorolor i j , 1  dat a j c l i s o t e i . ; t :^ s S t a t i o n . The followin g rao_e s s  io '  fo r ea c •  out:: ; . r i : : -  1-2. . 1~ -1922, th e rnasiniur-i , ir.inu n -  d  e, . •  : ; : . e r t a r e s ; th e r a i L, snowfal l an d t o t a l p r eov r i f a t i ou ; an d tr. e cur s : f 5' . -19. fh e averag e mea n t e -  era.tu.re , ave r t e s r e o i y i t a t i o n , averaare sunshine , fo r eaol - M O nth, ove r th e fiv e ;a r s re -,is t o 1921 , ar e als o show ; i n th e t a o l e s . Seoord s o f r m i Deity, r e l a t i v e auiridit y an d evaporatio n ar e ava i lab l e fo r years 192 1 an d 192 2 only . J a n . Fe"b. Liar . A p r . May J u n e J u l y Aug. S e p t O c t . Nov. D e c . 1920 Max. • P . 5 7 . 0 4 6 . 0 5 7 . 0 7 2 . 0 7 7 - 0 9 0 . 0 96.O 9 8 . 0 8 2 . 0 6 1 . 0 5 2 . 0 45.O M i n . "P . 5 . 0 1 8 . 0 1 8 . 0 1 9 . 0 5 5 . 0 4 0 . 0 5 2 . 0 4 4 . 0 4 0 . 0 2 5 . 0 1 9 . 0 2 0 . 0 Mean 2 4 . 6 8 5 0 . 9 0 5 8 . l l 4 5 . 7 0 5 5 . 5 1 5 9 . 7 0 7 2 . 1 4 7 1 . 0 5 5 7 . 6 0 4 4 . 9 0 5 8 . 5 0 3 3 . 6 0 Max. • P . 54.0 5 0 . 0 6 2 . 0 09.O 8 2 . 0 8 6 . 0 9 0 . 0 9 2 . 0 7 2 . 0 7 0 . 0 5 5 - 0 4 9 . 0 L92I Min . o p . 1 2 . 0 1 0 . 0 1 9 . 0 2 6 . 0 5 4 . 0 4 3 . 0 4 7 . 0 4 7 . 0 5 7 . 0 2 6 . 0 2 . 0 - 5 Mean "P . 2 9 . 0 5 2 1 . 1 4 3 8 . 9 7 4 4 . 8 5 5 6 . 1 5 6 3 . 6 0 6 8 . 4 5 6 7 . 9 2 5 5 . 2 1 4 8 . 9 5 3 4 . 8 6 5 2 4 . 2 1 1922 Lax. Min . Mea n Averag e Mean for 5 years *P. *P . °P . previou s to 1921 5 7 . 0 4 ^ . 0 5 0 . 0 6 8 . 0 8 5 . 0 9 4 . 0 9 8 . 0 9 1 . 0 8 2 . 0 6 2 . 0 4 6 . 0 4 9 . 0 2 . 0 - 1 . 1 2 . 0 2 6 . 0 2 9 . 0 4 7 . 0 4 8 . 0 5 0 . 0 4 2 . 0 3 1 . 0 2 5 . 0 - 5 . 2 0 . 8 8 2 0 . 6 2 5 5 4 . 1 4 5 4 5 . 0 8 5 4 . 3 7 6 7 . 4 7 7 0 . 7 5 6 7 . 8 3 6 0 . 0 3 4 8 . 8 9 5 4 . 4 6 2 2 . 0 9 2 5 . 9 4 2 7 . 1 4 3 9 . 1 5 4 6 . 7 7 5 4 . 7 0 6 1 . 8 0 6 9 . 3 2 0 8 . 6 5 5 9 - 5 2 47 .  2 4 5 6 . 5 4 2 8 . 5 5 -113-A careful study of the mean monthly temperatures, as shown Dable 2XVI indicates that, in the main, the temperature con-Lons experienced in 1920, 1921, and 1922 did not depart gre-j from the average as expressed by the mean monthly tempera-s for the five years previous to 19 21. Probabl y the most nificant temperature factor, in relation to the growth of cl£ crops, is the mean temperature during the months of Hay, e, July and August. Th e average mean temperature for these r months, as shown "o-j  the above table, was just below b4 a3 the five years previous to 1921; just above o4*p for 1920 1921; and just above 6p°P for the same period in 1922. Th e ,n temperature during April, which would undoubtedly have a iat influence on the temperature of the soil at the time the ips were getting started, was slightly below the average in fh of the years 19 20, 19 21 and 19 22. Thi s was especially no-jeable in 192 0 v/hen the mean temperature for April was three jrees lower than the average for the five years previous to 61. Th e highest monthly mean was experienced in July 1920, 3 temxerature for this month being almost 3*1? above the aver-e. Th e highest daily temperature was registered in August of s same year. I t is apparent, therefore, that the mean temper-ures experienced during the growing seasons of 19 20, 19 21 and 22 approximated closely the conditions encountered in previou ars. nevertheless , there was sufficient fluctuation in the mperatures during each of these years, to provide a variety ' conditions representative of what may be expected to occur om year to year in the district. J a n . 5'eb. ,'.ar. A p r . I'M;: •' u n e J u l y 4h U  i^  • o f l p t . i C t . : :ov. J e c . ?o •  • 1 Hain fe i r . . . 29 - -• >4 l . ; 3 • Ob .?e .r.4 . I  ; i . 5 i 1 . S O . 7 c = . 3* .11 i^o S n o w f a l l i n . 1J5.5 1 .2 . - -__ - -- -__ - -; • • * i n . ? I B B X 0 A A T I l i T o t a l i n . I . o 4 . 0 3 #46 1 .03 #06 • 9" • 24 #18 i o l I#oo • ' . w *>*» i t ' •  o R a i n f a l l i n . . 0 5 . 1 3 . 2 1 1 . 1 3 1.3u 1 . 9 . j •34 . ? : : . ; 9 • 2 3 • 3 -i . >  1 " . 5 1 H w n m i y 1 9 2 1 s n o w f a l l i n . 9 . 0 • 5 . 4 __ - -- -- -- -- -- -i t . 5 i •  •» 27 .7 r r o o i p i i ' o t u l i n . l v c i • i i • 7 • > i . l > i . 3 c i . 9 v * ^  * • • i r - • • ; r . 2, 5 - A  . . ^. ^  * i l . j wH"cion. 1G l a i n f n ; i : ; . — — • w  • * • **• > j " . ' J w • . „ - h . • 1 3 - • . -+• •-  2 X .  * / w . _ > 22 I 3:;ov; t i . . . • » •  v -• •  t . •i. .. . •  * • . ' - -- -- -- -• ) •  • • V ; i i T o t a l >»*. T • 7~» • A . .* •  i -. .  j * •  y # - ' . ' • * Avr rn - 'o J T I c i r i t a t i o n for 5  ;.«ar a i r r v i v . . t j t o 1->21 * • • • * * r ' • •" • * > • *  * • • w • ;  L. • • . . * -115-From Table XX7II it is evident that the total annual pre-itation during each of the years 1920, 1921 and 1922 was ghtly in excess of the average for the five years preceding 1. Thi s increase in the natural precipitation was particu-•ly noticable in 19 22, when the combined rain and snowfall v.'ae 'e than $  inches in excess of the average for the five years seeding 1921. I t is to be noticed, hov/ever, that in 1920 and !2 the rainfall durin^ the foar main gro in ; months, I.".ay, June Ly and August was actually aoout an inch lower than the aver-3 for this period. I n 1921 the rainfall during the foxir mon-3 of most rapid growth was alwost 2 inches in excess of the srage. Th e autumn of I9I9 v/as an unusually dr one , which aid tend to lessen the amount of natural moisture stored in e soil for the use of tne 1920 crop. O n the other hand be-een the time the 1920 crop was harvested acid the time the 192! op was planted there was a total preoi] itction of over 7 inch-, much of which w s undoubtedly stored in the soil for the us< the 1921 crop. I n June 1921 the rainfall was almost twice e average for the month, while in June 1922 there was only e-fifth the average precipitation. I t is apparent therefore, at while the total annual precipitation during each of the tars 1920, 1921, 1922 was slightly above the average, yet the fierences in distribution of this rain and snowfall for the rerage years were such as to provide quite a wide range of con-.tions. I t is considered, therefore, that the precipitation iring 1920, 1921 and 1922, while on the whole greate r than may 1 commonly experienced in the Glzanagan /alley was, neverthe-• -116-, fairly repreeentatiTe of the fluctuations in rain and fall usually encountered in this district. i \ J a n . Feb . Mar. Apr. May June J u l y Aug. S e p t . Oc t . Nov. Dec. 1920 hours 45 .4 I 6 3 . 2 117.8 142.8 239.3 239.3 343.6 294.0 186.3 123 .3 86 .3 3 1 . 1 1921 hours 68.2 79 .6 137.4 175.9 294.0 225 .1 342 .1 284.0 170.2 133 .1 63.5 5 6 . 1 total for yr. 2015.0 2069.2 1922 Averag e f o r 5  y r s p r e v i o u s t c hours 70 .8 IO5.8 128.6 1 9 5 . 1 2o9.2 5 27.0 3 2 1 . 1 245.7 206.7 158 .2 5 1 . 1 45 .5 2122.8 1921 h r s . 59-0 90 .7 135 .8 177 .8 223.4 242.8 p28 .8 284.7 207 .1 159.0 61 .3 4^ .5 1998.7 -•v.-^sr-^. -118-Inapection of Table ££7111 discloses the fact that the tal annual sunshine for each of the years 1920, 1921 and 12 was several hours in excess of that which might he expec-I from a review of the records of sunshine registered during 3 five years 1916 to I92O inclusive. Furthermore , a consid-ation of the records for the months, Lay, June, July and gust reveals the fact that the total number of hours of nshine for this period was 116^.0 in 1922, 1145.2 in 1921, d 1116.4 in 1920, while the average for the five years pre-ous to 1921 was only 1084.7 hours. Th e explanation lies in e fact that the years 1917 and 1918 were characterized by unusually large number of days when the sky was overcast. 1 1917 "the total annual sunshine was considerably below the rerage, only I9I2.9 hours being registered. Similarl y in 118 there was apparently less sunshine than usual, for, Lring Ivlay, June, July and .-lUgust there were only 966.9 hours len the sun was not obscured. I t is evident, therefore, that Lthough there was considerably more sunshine experienced iring 1920, 1921 and 1922 than had been the rule during the sriod between 1916 and 1920, yet it is altogether likely that he conditions which prevailed during the time that this Kperiment was in progress were quite typical of what may ormally be experienced in the Okanagan Valley. Table X.ZLA*  I  onthly wina vexooiby J a n . Feb. l»_ar. k o r . May June J u l y u l l i J . Dent . o c t . o v . l e e . G r e a t e s t i t y 1 9 2 1 5 4 8 3 7 4 4 0 1 4 5 1 4 2 8 3 4 ^ 4 3 0 3 0 8 3 3 ? 9 4 1 ^ ^ 307 in V e l o c -24 i i r s . 1922 3 1 1 7 6 1 3 9 7 ^ 0 3 4 3 4 ^ 2 9 3 3 0 ; 8 7 3 5 4 4 3 2 500 G r e a t e s t i t , / i n 1 1 9 2 1 4 3 ryj 4 2 3 3 3 3 4 1 3 8 3 2 50 37 44 ; 3 V e l o c -hr . 1922 39 4 3 4-b 3 5 3 1 28 27 >o 29 ;>o 4 2 ixVero ^ e i t / f o r 1 9 2 1 9.8 1 0 . 6 8 . 9 9 . 0 8 . 9 8 . 0 1 0 . 0 0 . 3 9 - 9 1 1 . b 0 . 9 C Q / •  c Jeloc-llonth. 1922 9 . 2 9 . 8 9 - 2 2 . 0 8 . 1 9 . 3 8 . 7 8 . 0 8 . 4 7 • 0 0 Q 9 . 0 x r e v a i l i n ^ D i r e c t i o n . 1 9 2 1 192 2 South Sout h bou fcn  . j e s t South Sout h o o u t a j_ias t u o u t n ^ a a t N o r t h V.es t l i o r t n o o u t n nats t n o r t h . e s t Horth lort h -es t • e t .t b o u t ' i - e s t o o u t n ; e s t b o i t i <es t b o u t h _,as l u o u t h SOU t'i S o u t h u a s t b o u t a -120-glanoe at Table XXIX suffices to suggest that the movement p air over the site of this experiment, may have been an lportant factor in determing the rate of evaporation from the >il, and the amount of transpiration through the crops. I n 121 the average movement of air was over nine miles an hour >r every hour in the year. Durin g the month of Lay j>0 mile l hour gales were experienced ooth in 1921 and in 1922, while lere were times during the months of June, July and August i each of tnese years ,'he n the wind velocity exceeded 25 miles l hour. Exposur e to wind is often quite a local condition. lere is reason to relieve, however, that the Summerland tation, while it undoubtedly occupie s an exposed position, is svertheless so situated as to be subjected to air movements Lmilar in intensity and direction to those which occur over a irge area of trie truck-growing section of th e Okanagan. nose v/inds ;hic h have been ooserved to cause the most noticabln acrease in evaporation and transpiration sweep up the /alley rom the South. Th e drying influence of these winds is felt jre or less throughout the entire /alley . I t seems plausible D infer, therefore, that the air movements experienced at the immerland Station are indicative of conditions which the ijority of truck crop growers in the Okanagan /alle y must be repared to meet. ON ONvO -sj- •sfr CM CO H tr^ NO NO if\v0^o ir\ c— ON CO WHcOHHHvOiAO^-f<\^Ostr~HCOLr\^^ WvOOJ WOOHO K\K\^J- ^t- ^f- -3- v£> UN, UN, c— C-CO CO Cr- t— vO vO •=* CO NO c— -X> Lf\vO vO u\ v£> irv I I I ^ I CO "3" ^X> l^-v£)HCMCMO-=t K\vO K\. UN, ONCO ON CM H vO KVO III -—i- • tf\X> ^t I O <-r\ic\^ K\^ ^t- ^j- ^- -=t rov-* *X> vD vD UN,UN.NDUN, c— co i i o tr— LT\ ^o LT\CO I •* if\"Nococo i ooa<t AOIA I H ^ ** <* •* 1 I ^••^•^•vOiA't I NN ^}- "A ^ -<\ NJ- lir\Lr\-^-ir\Lr\tr\|Lf\-^-i<N •^ u\cO rAC- UN, I I <—I KN.~X> O H I C\l lA^t KM<\ON I CMtr~ I \D Lt\C- I UN, "* IT- ON LT\vO I I C—C—l-f\NOvO I tA •** NO vO lA C— I \0 >A I CO<t if\ I X> X> CM I I K\u\KN."+*\ I vOvOrHCONOhO\hf\CMONOtr-CO i<\C—NO COCO O c— c— I I X> O C— UN,VO I UN. ir\«©> O vO CO CO CO vD Lf\ NO UN,vO "A -X) u\ LA O CM -«t ON^* X> | NO C—CO ^•C^HCOOH'* o^OOCMKN-AONCMrA I UN, •<* -<3- •>* ^X> X> |-<t'=J-'4-iALr\Lr\^t'* LT\cO X> CO "-X> NO VO CO C— vO C—--O I O -* rA rH •* tr-O ON CM O C- O C— fA CN^CO CN"NsO CO -sj- ON -<t \D ^ ^ u\-si- u\ UN. -*t u\ u\ •sj- -j- NN. u\ •sj-'d-rov'^-"*"^ ^ -O^^ X> H CM Lf\ rH rH IT--^ Lf\ *AC—'tC— CM UN. ONvO X>vX>CO O X> X) C— UN, o IANO ^O u\ LA ^- -3- u\ H CM ecv-^t- LT\NO C--CO ONO H CM ,-A^- ir\ x> ir-oo ONO H W t^^- f\vo tr-co HHHHHHHHHHWWNWWWWWW T&D16 AAA.* - uoaoj.uu.au . 1921 192 2 Date Jun e Jul y AUQ; . Sept . La y Jun e Jul y Aug . Sept . 4 ••'  <l  4  t  1  4  4  4 29 4- 9 4 0 u O 7 1 5; > ^ 8 J? 7 6 7 30 8 9 M  > 5 7 4 5 0 4 6 6 9 6 6 31 4 0 u O 5 1 5 0 7 9 An examination Of Table 1L&A leaves no duubt as to the truth of the contention that the relative humidity of the atmosphere at the Summerland citation durin? the summer months is frequently quite low. Ther e is no grounds for supposing that this condition is peculiar to the atmosphere in the neighborhood of the Experimental station. Jhil e local atmospheric disturbances are of frequent occure ice in the Okanagan /alley , it is nevertheless altogether probable that, in tie large, the atmospheric moisture conditions experienced vvnere this experiment v/as conducted are representative of those conditions encountered v/herever truck crops are grow 1 in the /alley. I t is universally reco^iized that, other conditions being identical, a low relative humidity increase s the rate of evaporation, and tends to cause plants to traiiSpire more water. Th e effect of a low peroentage of moisture in the atmosphere is, therefore, to increase the v/ater requirement of crops, and to intensify the necessity for taking every precaution to check the evaporation of v/ater from the soil, '..hil e the lov/ ative humidity of the atmosphere over the site of this leriment may have appreciably increased the losses of water >ough evaporation and transpiration, nevertheless, as has •n shown, such losses were in all probability no greater in those likely to be ex-'erienced by growers of truck crops 'oughout the Valley. CM CM ON ,-! r~>, CM H • -p . p< a <D O • bO rf •>i :--. H 3 t-3 0 c 2 1-3 •H r! •H • 0 •H • S •H >5 od a •p • ft a Q -H ca •"3 CO • od CM --:-H CO O • 0 o ON o Lf\ o ON .3 ON o \j crs H O CVJ H H H o H ex o •--H CO A o •A C-co CM '-'A CM CM 'A CM H A-A o H CM p I CM H r<A vO V CM O CO oo CM CM CM CO H ON O 3\ H '-A - 0 o o CM CM H vO H CO o C-H '-A 3 H :-l O 3 CM ~ H CM H • a .-I CD O CM H ON O CM H -"A H .0' o Al CM .O CM O ON a -CM CM H -A H CM CM ir\ LT\ rc\ 0\ H CO o o CM O • A "A NO CO CN M CM o H H 1 CO 3 CA CM CM CM CO 'A H H CM H H "A CM o NA 3 CM J H N£> H ,-: H 'V CM CM H K\ co ' 3 CM 3 CM A Al C-CM K\ •--0 * K\ ^A CM vO CO \ H .A H co 0' CM 'A CM "A H •A CM o> eg A) CM 3 ^ O r-i H H CM :—. KN, H A-H 'A .-; -ii * R 4* 1 o l -H 0 »-3 ID =1 I ON CM '•A I '"J H r I CC r ) U> H H OJ ^ H H oi O O -\J J H CO O -' rH O M ' ! I ON • I I H SO I rH rH o M . .1 r<\ H H H CM r ! j OJ O H ir\ H OO H K\ i—. T H C— H • • H tf\ - • D :. O CM 1 t OJ 1 1 > c— H 00 i— <* H H H "4 H XN. OJ 3 rH H OJ •^r rH !\ H H H <\ c— H cr\ OJ «* O iA H C-—• OJ >r\ OJ H H ON o 'A rH O <> H H H-0 0 OJ o «A rH ,H "J-H 3 CM M OJ c^ : 03 o •* CM CM OJ 1 CO -o O Z> rH C~ CM H -•4-an CM rH O 1 •<\ 1 c\ -\ ON T* • •«* o •O o c— • • o o oo CM OJ C\ lf\ O OJ CO 1 ON o • 0 o ' -• •••1 H • • H >N o C— . J OJ r-\ O 1 rH 1 oj o rH CM 0 CO H • o H T^ H * : 1 C. CO rH • 0 is \ CM CM • ON H H • 3 CVJ — CVJ r —i • H CM CM N N • CVJ r • CM CO H • C\ XI • rH CVJ • OJ OJ CM H • CM ' 0 CM ) CM • "M 3 H -J CM t -CM H OJ H • CM r \ CM CM • ON M l<N,rO AJ OJ OO 1 rH 1 • O rH r<\;c\ • \ SN. o \ OO ) "> -: I . -126--In order to secure, the above records of evaporation a gal-nized iron tank six feet square and three feet deep v/as sunk i the ground till the rim protuded only about an inch above le surface of the soil. Th e tank was then filled with water 3 > within four inches of the top, and the daily evaporation sasured in hundredths of an inch. It is interesting to note tha t the total evaporation dur-lg May, June, July, August .and September 1922, was over twenty Dur inches. Tha t is to say, a greater depth of water was vaporated from the surface of the water in the tank than was pplied, during the entire season, to any of the plots in this xoeriment. Extensive investinations carried out oy ^ortier (11) have hovm that the raain jovorning Tactor in the rate of evaporation rom a soil is not the temperature of the soil or air, the lovement of tne find , or the humidity of the atmosphere, but .he percentage of moisture in tne top layer of the soil. Thu s evaporation from a saturated sandy lo^m v/as over twioe as great is that from a water surface under the Same climatic conditions then the same soil contained onl# 17»5;« of m  ter tne loss from evaporation was found to oe less than that from a water surface There is every reason to believe that the above figures Of evaporation indicate the general conditions which exist in the Okanagan. .hil e the rate of evaporation was not as exces-sive as that observed in many other irrigated regions, never-theless, it was sufficiently ?rea t to indicate the necessity for adopting i n the Lkana_;an every feasiole method for the -127-tuction of evaporation losses* From this brief review of the climatic conditions which evailed while this experiment was in progress it is evident at the location of the experiment is such as to cake the suits secured applicable to a lar^e area of the Ckanagan lley. Furthermore , it is apparent that although the experi-nt has been conducted over a period of only three yearst th e ather experienced has 'oeen  suc h as to test the efficacy of rious irrigation practices under as wide a range of climatic nditions as is lively to occur, with any frequency, in the ucfc crop sections of the Valley. -128-he Influence of Soil on the Results of this Experiment. As has already been stated, the soil on which this experi-ent was carried out is a fertile sandy loam about two and a alf feet in depth, underlain with fine sand. I t is quite pos-ible that altogether different results might be secured under ifferent soil conditions. However , as has already been point-d out in the introduction to this report, the soil formation n the site of this experiment is typical of that which prev -ils in many of Ihe true]: c roo sections of the Okanagan* In determining the reliability of the data secured from ,n experiment of this nature, consideration must be given to ,he possible Inflnencs of soil heterogeneity. I n this conneo-,ion it is important to oear in mind that the natural formation md tn e previous treatment of the site of this experiment were luch as to promote uniformity of soil conditions. Furthermore , rhen oats and potatoes jere grown on tne land previous to the Inauguration of this experiment tnere was no noticeable dispar-ity in the yields obtained ±rom the several sections later sccupied by the various plots. Th e fact that no appreciable Amount of grading was necessary to fit the land for irrigation was also conducive to uniformity of soil conditions. I t is true that the slope of the land is slightlj more abrupt in tne area occupied o y Plots C and u  i n 1?21, than in tne area occup-ied by the remaining plots and tha t this increase in gradient is accompanied o y a small decrease in the depths of the surfaoe soil, nevertheless , it seems justifiable to conclude that, all in all, the reliability ox the results has not been greatly -12?-paired by variations in the fertility or depth of the soil, by inequalities in the slope of the land. ' -1J0-I e Influenc e o f Cultura l Lethod s o n th e Result s c f v-.l a ^.xperi.^ent. From t h e s ta tement s :  ±d e i n th e in t roduc t io n t o tr.it . (port i t i 8 manifes t t h a t t  . e matur e c f t o c u l t u r a l etr.ud e lopted na y nav e a n approoiaol e ef fec t o n th e ree . i ' t bocure d *om i r r i g a t i o n experiments . Consequentl y th e r e e . i fc  c f t i B tperiment -rus t b e considere d t o appl y d i rec t l y ,  onl y .er e *  e ^sterns o f s o i l an d cro p managemen t a r t si i i l a r t o V-ct o ...ae r l ich t n i s experimen t ..a s ca r r ie d Oct . I t i b a i t c •  ' >_ r ble t h a t , wher e l e s s e f fec t iv e ean s o f maintainin g s e l l B r t i l i t y o r l e s s e f f i c i e n t metnod s o f conservin g !,oibtur e -  e.e a vogu e th e quan t i t y o f i r r i g a t i o n .ute r require d i u r t  e roduotion o f crop s woul d b e ma te r i a l l y increa toa . Jever thc les B t i B considere d t ha t t h e cu l tu r e r ece ive ! by  t  :  oror e i n h i s experimen t wa s suc h a s migh t b e prac t ice d t o advvntH- e b y lommercial grower s o f truc k crocs . I n vies ' c f '  ;his s i t u a t i o n t seem s l o g i c a l t o conten d t h a t an y influenc e v;hiu h c u l t u r a l lethods ma y hav e ha d o n th e r e s u l t s o C t h i s experimen t cwii a >e duplicate d wi t h p r o f i t b y th e growe r o f truc k crop s i n th e Dkanagan Valley . - 1 ^ 1 -The Influence of Experimental Technique on the Results oJ this Experiment. Throughout this experiment an earnest attempt was made to provide growing conditions which approximated as closely as possible thos e which would normally be encountered in the field. However , the fact that the plots were only a fraction of an acre in area, and that it was impossible to repeat the experiment undoubtedly introduced a large possibility of experimental error. A s explained in the outline of procedure, every effort was made to ensure a uniform stand of each crop in each plot. Great care was taken in making all measurements and weighings. Th e Miners' Inch .Soxes used in recording the water applied were checked o^r  measuring in gallons the volume of water delivered in a given time. A  Fairbanks ldorse acale was used for weighing the crops in the field, while a Christian Becker Balance was employed in making the soil moisture determinations in the laboratory. From the point of view of correct experimental technique the planting plan adopted is open to several serious object-ions. Th e different types of vegetables were grown side by side in single rows in each plot. Th e yields secured under such conditions are in no sense strictly comparable to those which might be obtained were each vegetable to be grown by itself on an acreage basis, undoubtedl y the root systems of the various crops crossed and intermingled making it imposs -1 ^-+'>^S^  -132-ble to determine accuratel y the water requirements of each ndividual crop. Furthermore , the portion of each crop above ground was subjected to different atmospheric conditions than rould be experienced were each crop to be grown in a block by .tself. Again , those vegetables which were planted in the )utside rows of each plot enjoyed an unfair advantage over their neighbors within the plot, ho t only with regard to availability of soil fertility, sunshine etc.; but also with reference to the soil moisture at their command. Th e fact that the outside rov;s of experimental plots produce greater yields than inside rov/s is a matter of common observation. Similiarly the competitive effect of adjacent rows has much experimental proof. Accordin g to i'ickering (j>Q)  this behavior is at least partially due to the excretion of toxic substances by the plants. Th e production of such substances is still a debatable question, but whatever the cause it is universally conceded that competition between adjacent rows and excessive yields of the outside rows, are factors which have a consider-able bearing on the reliability of experimental results. Uotv7ithstanding these obvious short comings in the exper-imental technique employed in the conduct of this experiment, it seems reasonable to assome that the results secured indicate at least the relative behaviour of the several crops under various conditions of irrigation practice. • —  —  .  i  • • • • . . . . . • aoHciusioiis There can be no finality to conclusions arrived at from a survey of results obtained in a  single experiment, conduct-ed over a period of only three years, and exposed to the many modifying influences referred t o above. I t is considered, however, that the information already secured is sufficiently reliable to justify the following general statments, which may be of interest and of value to growers of truck crops in the Gkanagan Valley. 1. ./her e care is e:cercised in applying irrigation water, and where approved methods of soil management are followed, satis-factory yields of many truck crops can oe obtained with com-paratively small applications of irrigation water. 2. ./he n the soil is maintained in good physical coudition and v/hen proper attention is given to the preservation of soil fertility, the quantity of water required to give the highest yield per acre of such crops as tomatoes, potatoes, beans cantaloupes and corn, is considerably smaller than -enerail y conceived. 2. Applicatio n of water in excess of the actual requirements of truck crops is not only a wasteful practice, but actually reduces the total yield and postpones the date of maturity, particularly of such crops as corn and cantaloupes. 4» Althoug h such crops as carrots, cabbage and cucumbers give an increased yield from the application of relatively large amounts of water, it is questionable whetner such -1>4-(.norease 18 economical. Th e inoreaee in yield is not always Buff iclontl;, great to cor^r the coat of ; reevring and arriv-ing the additional water. 5. I n t.'.ose sections of the C-E&nagan /alle y ../.ere the Br;..uai precipitation is not more than lu inches ana .here :.ot more than six inches of irrigation water is available during tn e growing season, or where no water is available ufter Jul,/ iu; it v/ould seem inadvisable to undertake commercial production of truck crops, .j'it h proper care, however, ve getabies for home use may be produced ..'ith even this t;r.ial l quantity of water. 6. I t is inadvisable 1o apply large quantities of water to the soil immediately previous to sowing seeds of truck crops. large applications at this time appear to enill the soli to such an extent as t0 seriously reduce the percentage of germ-ination, particularly of the heat-loving crops, such as corn, beans and cantaloupes. I f sufficient of the natural precipi-tation to ensure good germination has not been stored in the soil, the land may, v/ith advantage, Qe irrigated ten uayu or so before seeding time, cultivated thoroughly, and then allow ed to warm up before sowing the seeds. 7. Application s of 3 inches of water at 1> day intervals can be expected to give satisfactory results only where water is applied according to approved metnods, and where cultivation is practiced as soon after irrigation as the ground can oe worked. 8. Thre e inches of v/ater per application appears to be neo--134-essary to ensure uniform distribution of moisture In the type of soil most prevalent in the truck crop sections of the Okanagan Valley. 9. Th e type os woil most prevalent in the Okanagan will not take up moisture at the rate of 3 inches per eleven hour day unless adequate measures are taken to ensure the incorporation of plenty of organic matter with the soil. 10. Mos t of the distributing systems in the Okanagan Valley are operated so as to deliver water to individual growers on only two days of each week, or four days a fortnight. Conseq -uently it is of the utmost importance that the soil'be thor-oughly prepared previous to irrigation, and that it be main-tained in such a condition that it readily absorbs and retains moisture. 11. Irrigatio n should never be regarded as a substitute for cultivation. 12* Ever y effort should be made to conserve the natural precipitation. 15. Physiologioa l diseases or disorders of the tomato, such as blossom-end rot and cracking, can be at least partially controlled by maintaining proper conditions of soil moisture. 14. T o make the most efficient use of his available water supply the irrigator must study the moisture holding capacity of his soil as well as the water requirements of his crops, and then apply his water accordingly. 15. I n any attmept to determine what is the most economical practice for his particular conditions the grower must not -155-Dnly consider yield per acre, "but must also take into account ^ield per acre inch of v/ater. H e must "balance the cost of i/ater against the rental value of land. '(her e v/ater is rela-tively more expensive than land it v/ill pay the grower to apply a comparatively shallow depth of v/ater over a large area of land. iJve n where v/ater is plentiful and land is ted, the irrigator is justified in increasing the amount of v/ater v/hich he applies only so lont as this practice resu-lts in an increase in yield sufficient to more than offset the cost of procuring and applying the additional v/ater. -136-I I S T O F REFERENCES . 1. Bark , D.H. 191b. Exper iment s o n th e Economica l Us e o f I r r i g a t i o n w a t e r i n I d a h o . U.S.D.A. b u l . 3 3 9 . 2 . Souyoucos , G-.J . 1911. Transpiratio n of /hea t Seedlings as Affected by Soils, uy Solutions of Different Densities, and by Various Chemical Oompounds. Proceedings of tinier.Soc.of Agronomy. /ol. > p.130 p, Briggs , Lyman J., L  3elz, J.O. 1911. Dr y Farming in delation to Rainfall and Evaporation. U.S.Bur.Pl.Ind. .oul.128. 4. Br iggs , L . J . , &  Shan tz , H . l . 1912. Th e - i l t i n g C o e f f i c i e n t f o r D i f f e r e n t P l a n t s ari d i t s I n d i r e c t D e t e r m i n a t i o n . U.S.D.A.Bureau P l a n t I n d u s t r y , Bu i . 230 . 3 . Br iggs , I . J . ,  &  Shan tz , f i . l . The Wate r Requirement s o f H a n t s . 1913 * U.S.D.A.Bureau P l a n t I n d u s t r y . 3 u l s . 28 4 «  2C3 . 6 . Cameron , P . K . , &  j r a l l a g e r . F . E . I9C8. L'oistur e Content c  Physical Condition of Soilu. U.S.D.A.Bur. Soils, Bui.30. 7. Clarke , P.',-. 1911. Th e Date of Geochemistry. U*S.Geological Survey. dul.491 . 8. Torbes,  R.H. 1^06. Irrigatin g sediments and their Effects Upon Crops. Ariz. Exp. dtn. , Bol*52« 9. Fortier , Samuel. 1907. evaporatio n Losses In Irrigation and Bater Requirement of Crops. U.S. Off ice of Bacp. otns. Ful.177. 10. Fortier, Samuel, ft jeckett, d.H. 1912. evaporatio n from Irrigated Soils* U.S.Office of Bqp.Stna, ±ml.248. 1 1 . F o r t i e r , e l . 191o. I s e o f r a t e r I n I r r i g a t i o n , pp . 174-247 . IlcGrrav;-Hill Boo k Compan y I n c . ,  He w York . 12 . I b i d , P . 127 -1 , . I b i , J a r d n e r , .  . :.  ,  r a d f o r d , I . C . , ft  i looker , k .U . 1922. ! • o f F r u i t p r o d u c t i o n . p . ; 3 ' _ •  I n c . ,  Je w 5f©rfc « 1 5 . Jrantham.G. l .  cCool , L. ] . 1920. r iment e o n S o i l M o i s t u r e . ; t . ] u l . 2 (1920 ) B o . ; , PP .142 -144. l b . [ a l l , •  •  , R u s s e l l , F . J . 1 9 1 1 . F i e l d T r i a l s an d t h e i r I n t e r p r e t a t i o n . v,pplenent t o t h e J n l . o f th e Boar * o f : l t u r e , .  ondon . - i>8-17. " 1 aminalt , W.G . 1?18. Determinatio n o f th e Qu.%$  o f /a te r b y Ana ly t i ca l Experiment . Proc. Amer . Soo . Civ . Engineers , 4 4 (1918 ) No.2, pp . ^u7->^7 . 18. Harding , S.X . 1919, Relatio n of the Moisture Equivalent of Soils to the Moisture Propertieb under Field Conditions cf Irrigation. Soil Soi., 8 (1919) No.4, pp.202-312. 19. Harris , F.S. 1917. Th e Irrigation of Potatoes. Utah Exp.Stn. Bui.157. 20. Harris , F.S. 1917. Th e Irrigation of Sugar iiee^^. Utah Exp.Stn. Bul.l^b. 21. Kilgard , E.V;., &. loughridge, R.H. I898. Enduranc e of Drought in Soils of the Arid Region. Rept. Cal. Agr.Exp. otn. 1897-78. pp.40-54, 22. Kearney , Thos. H. 191}. Th e lilting Coefficient for Plants in Alkali Soils. U.S.D.A. Bur.Pl.Ind.Circ.109. 23. Kiesselbaoh.T.A . 1918. Studie s Concerning the Elimination of Experimental Error in Comparative Crop TestB. Nebraska Exp.Stn.Research Bul.lJ. -139 24. Lewis , 0.1., Kraus, E.J., & Rees, R.W. 1?12. Orchar d Irrigation Studies in the Rogue River Valley. O.A.G. Exp.Stn. Bui.11^. 25. Lloyd , F.E. 1908. Phys io log y o f ba e S tomata . J - r n e ^ i o i n S u i t u l i c n o f -..as-iin^to^ . 26. Lyon , T.L . ,  P i p p i n , E . G . , &  Buckrnan , K.O . 1920. S o i l s , The i r P r o p e r t i e s an d l ianagement .p .24 6 I.laomillan Co . ,  Ne w York . 27. E o C l a t c h i e , A . J . 1902. I r r i g a t i o n a t t h e S t a t i o n Farm . 1398-1901 . A r i z o n a , S t n . B u l . 4 1 , p . 4 8 . 28. Patten , K.E. 1909. Hea t Transference in Soils. U.S.D.A. Bur.Soils, Bui.59* 29. Pickering , Spencer U. 1 9 1 1 . Exper imen ta l E r r o r i n H o r t i c u l t u r a l Work . Supplement t o th e J n l . o f th e Boar d o f A g r i c u l t u r e . London . 3 0 . P i c k e r i n g , Spence r U . , 1920. R e p t . o f wObur n Exp . tfruit  Farm , No.17 . >1. Powers, V/.L. 1914. Irrigatio n & Soil Koisture Investigations in Jeatern Oregon. O.A.G. Exp.Stn.Bul.122. -140 32. Richman.E.S . I893 . I r r i g a t i o n o f Po ta toes . Utah Stn.Rept . I893.pp.179-180 . 33 . Snelson , '. , .H. 1922. I r r i g a t i o n practic e an d >.ate r 3e<iuir e exit s for Crop s i n a l b e r t a . Dept.of I n t e r i o r . I r r i j . ^ u l . o , p .44 . 34. ThOLison.H.C . 1920. Effect s o f Cu l t iva t io n o n oo i l Lois tur e and o n f i e ld s o f Certai n /e^etaUlf e Crops . Proc.Amer.Soc.IIort .Sci . 1920 . p .133 . 33. Welch,J .S . 1914. Irrigatio n of Potatoes. Idaho titn.Bul.78, pp.22-23. 36. Widtsoe,J.A . 1902. Irrigatio n Investigations in 1901. Utah Stn.Bul.80. pp.67-199* 37. VJidtsoe , J.A . 1908. Th e Storag e o f winte r P r e c i p i t a t i o n i n S o i l s . Utah Exp.Stn.Bui.104 . 38. ' . /idtsoe , J.A . 1909. Factor s Influencing Evaporation & Transpiration. Utah Exp.Stn. Bul.103. 39. Widtsoe,J.A . 1912. Th e Production of Dry Latter with dif-ferent Quantities of Irrigation ,,ater. Utah Exp.Stn. Bul.116. m iII1.LIIIN.IIIII 1 - 1 4 1 -40• Widtsoe.J. A . 1914. Principle s of Irrigation J?ractioe pp.286-515. Macmillan Company, New York. 41. Ibid . p. 124. 42. Ibid . p. 47 45. Ibid . p. 94. 44. Y/ood , T.B. 1911. Th e Interpretation of Experimental Results. Supplement to the Jnl. of the Board of Agriculture. London . 


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