THE USE OF SALINE IRRIGATION W A T E R ON FRASER RIVER DELTA SOILS A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN AGRICULTURE We accept t h i s t h e s i s as conforming to the standard r e q u i r e d from candidates f o r the degree-of MASTER OF SCIENCE IN AGRICULTURE THE UNIVERSITY OF BRITISH COLUMBIA October, 1953 STEWART i n the Department o f Agronomy ( S o i l s ) . THE USE OF SA'LINE IRRIGATION WATER ON ERASER RIVER DELTA SOILS by J." STEWART t h e s i s submitted i n p a r t i a l f u l f i l m e n t the req.uirem.ents f o r the Degree of Master of Science i n A g r i c u l t u r e i n the Department of , Agronomy ( s o i l s ) . The U n i v e r s i t y of October, B r i t i s h Columbia 1953 i ABSTRACT Two f i e l d plots i n the Ladner area, one sup-porting pasture species and the other i n t e r - t i l l e d crops, were i r r i g a t e d by sprinkler with water containing more than 13,000 parts per m i l l i o n of ocean s a l t s . Eight acre inches of water were applied annually, i n three eq.ual applications, the t r i a l being conducted for a period of two to three years. S o i l samples, obtained at appropriate i n t e r v a l s during the course of the i r r i g a t i o n t r i a l s , were studied i n the laboratory to determine the effects of the treatment on t h e i r physical and chemical properties. Plant y i e l d s were recorded and tissues chemically analysed to reveal a l t e r a -t i o n s , i f any, i n the uptake of mineral elements* Analyses revealed that, as a result of i r r i g a t i o n , marked increases occurred i n respect to s a l t content of the s o i l and osmotic pressures i n the s o i l s olution. Subse-quent dormant-season rains were observed to remove a large portion of the accumulated s a l t , but s u f f i c i e n t s a l t residue remained in the cultivated s o i l a f t e r two year's i r r i g a t i o n s to affect i n j u r i o u s l y the growth of a non-irrigated silage crop. i i The exchangeable sodium percentage of the s o i l was increased only s l i g h t l y i n the pasture f i e l d , but to a dangerous l e v e l in the cultivated f i e l d * Exchangeable mag-nesium was increased and calcium decreased in both s o i l s . The effects on s o i l calcium are considered to be important, since the s o i l s are already low in available calcium, and a further deficiency of t h i s element for plant growth is therefore threatened. Studies of s o i l structure revealed no destructive changes which could be d e f i n i t e l y ascribed to i r r i g a t i o n with saline water. Calcium uptake by the plants was generally depressed by the treatment, and of the tissues studied, a l l , with the exception of the grasses, showed accumulation of sodium Pea and silage corn yields were reduced by i r r i -gation, sugar beet y i e l d was unaffected,., and pasture grass y i e l d was increased e i g h t - f o l d . The quality of a l l crops was impaired by the treatment. The author is convinced that the continued use of t h i s highly saline water, except in very special c i r cumstarices, w i l l cause reduced crop yields and lead ultimately to serious and permanent impairment i n the physical and chemical proper-t i e s of the s o i l s . ACKNOWLEDGEMENTS The writer i s deeply indebted to Dr. D. G. Laird, the Department of Agronomy, for his kindly advice and guidance i n th i s study, and to Dr. C. A. Rowles, of the same department, for his h e l p f u l c r i t i c i s m s and suggestions. Sincere appreciation i s extended to Mr. R. H. Gram of the B r i t i s h Columbia E l e c t r i c Railway Company Ltd., A g r i c u l t u r a l D i v i s i o n , for his cooperation i n the project; to Messrs. K. Davie and C. Beharrell f o r pro-viding the land for the f i e l d studies; to Pumps and Power, Ltd. for the use of i r r i g a t i o n equipment; to the B r i t i s h Columbia Research Council and to the Department of Animal Husbandry for the use of specialized equipment; to the University Research Committee f o r the f i n a n c i a l assistance rendered; and to the Department of Agronomy for providing laboratory f a c i l i t i e s . TABLE OF CONTENTS ABSTRACT i INTRODUCTION 1 REVIEW OF LITERATURE 3 I SALINITY AND PLANT GROWTH , Osmotic e f f e c t s 3 " C r i t i c a l " s a l t .concentration 6 I n j u r i o u s e f f e c t s of s p e c i f i c s a l t s and ions 7 Sodium s a l t s 10 E f f e c t s of s a l t c o n c e n t r a t i o n on seed germination 14 . I I SALINITY AND SOIL • CONDITIONS Chemical e f f e c t s of s a l t s on s o i l s 15 S o i l s t r u c t u r e and s a l i n i t y 19 Reclamation of s a l t e d s o i l s 20 EXPERIMENTAL P r o j e c t o u t l i n e 26 Pasture P l o t 27 C u l t i v a t e d p l o t 28 Chemical procedures and methods . 29 P h y s i c a l methods 33 RESULTS AND DISCUSSION I r r i g a t i o n water a n a l y s i s 35 S o i l analyses i Pasture p l o t 38 i i C u l t i v a t e d p l o t 51 P l a n t s t u d i e s i Sugar beets, peas, and corn 64 i i Pasture grasses 69 P l a n t A n a l y s i s 71 SUMMARY AND CONCLUSIONS 75 BIBLIOGRAPHY 7? APPENDIX - EXPERIMENTAL DETERMINATIONS TABLES Table I Composition of I r r i g a t i o n Waters 36 Table II Pasture s o i l content of sodium as influenced by i r r i g a t i o n 43 Table III V e r t i c a l d i s t r i b u t i o n of salts i n p r o f i l e of pasture plot as affected by applications of saline water 44 Table IV Calculated osmotic pressure of s o i l solution at the moisture equivalent percentage and at the 15 atmosphere percentage (pasture plot) 46 Table V Porosity determinations on the pasture s o i l 50 Table VI Percolation rates for pasture s o i l 51 Table VII Calcium content of cultivated s o i l at various depths as influenced by i r r i g a t i o n . 52 Table VM Salt status of the cultivated s o i l as affected by i r r i g a t i o n 56 Table IX Calculated osmotic pressure of s o i l solution at the moisture equivalent percentage and at the 15 atmosphere percentage (cultivated plot) 58 Table X Pore d i s t r i b u t i o n i n the cultivated s o i l 62 Table XI Percolation rates for surface and subsoil of i r r i g a t e d plot 63 Table XII Sugar beet and pea yields as affected by i r r i g a t i o n with, saline water 66 Table XLTI Grass y i e l d as affected by i r r i g a -t i o n with saline water 71 Table XIV V i a b i l i t y of control and i r r i g a t e d peas 74 FIGURES Figure I Influence of saline i r r i g a t i o n water and winter leaching on cations extractable with NH^OAc in surface s o i l (0-4 n) of pasture plot Figure II S o i l • r e a c t i o n of pasture s o i l as affected by i r r i g a t i o n Figure III Influence of saline i r r i g a t i o n ... water and winter leaching on cations extractable with NH^OAc in surface s o i l (0-4fl) of cultivated plot . Figure IV S o i l reaction of cultivated s o i l as affected by i r r i g a t i o n Figure V Cation content as affected by saline water of plant tissues i r r i g a t i o n with PLATES Plate I Cultivated f i e l d , showing control and i r r i g a t e d plots of sugar beets and peas Plate II Damage to corn and elder-berry occasioned by accumulation of salts on foliage Plate III Stunted silage crop of corn and sunflowers on portion of cultivated f i e l d which had been i r r i g a t e d for two years THE USE OF SALINE IRRIGATION WATER ON FRASER RIYER DELTA SOILS INTRODUCTION I r r i g a t i o n i s an essential and well established practice in the agriculture of many ar i d and semi-arid regions where experience has taught that nature cannot be depended upon to provide a continuing and adequate supply of moisture for crop use, In many other more humid areas, the r a i n f a l l d i s t r i b u t i o n during the growing season i s unfavora-ble, and supplemental i r r i g a t i o n i s widely practised i n order to ensure maximum production. This i s p a r t i c u l a r l y true i n areas where land values are high and intensive cropping i n -creases the demands on the s o i l moisture,, The productivity of the low-lying delta lands at the mouth of the Fraser River is much reduced because of an inadequate summer r a i n f a l l . An examination of the Thorn-thwaite curve of potential avapotranspiration for the area reveals that a moisture deficiency exists from the l a t t e r part of June u n t i l September, the deficiency exceeding six inches during an average year (59 » 47)• Sound management practices on these s o i l s thus demand the us© of i r r i g a t i o n water to eliminate t h i s obstacle to greater crop production. Water for i r r i g a t i o n use in the area i s poten-t i a l l y available from sandpoints, deep wells, sloughs, and open drainage ditches, but, i n many cases, these sources are unfortunately contaminated with sea sa l t s (.59, 29). Magnesium and p a r t i c u l a r l y sodium constitute a large propor-t i o n of the cations i n these waters, the percentage sodium often approaching 90?. of the t o t a l cations. Since large concentrations of these ions are objectionable from a s o i l s standpoint, discriminate use must be made of such waters i f the vexing problems of s o i l depletion, erosion, waterlogging, st r u c t u r a l deterioration, and s a l t accumulation are to be avoided. This study i s concerned with the application of an extremely saline water to two f i e l d plots i n the Ladrier area, and an enquiry into the effects of such treatment on the physical and chemical properties of the s o i l and on the growth of cultivated crops and pasture species. 3. REVIEW OF LITERATURE I SALINITY AND PLANT GROWTH Pla n t growth i s a d v e r s e l y a f f e c t e d by s o i l s a l i n i t y f o r three reasons: osmotic c o n c e n t r a t i o n i n the s o i l s o l u t i o n may become so acute t h a t i m b i b i t i o n of water by the p l a n t root c e l l s i s r e t a r d e d or prevented; the i n d i v i -dual s a l t c o n s t i t u e n t s or ions may d i s t u r b the normal metabo-l i s m of the p l a n t ; or the p l a n t may be a f f e c t e d i n d i r e c t l y by the poor s o i l s t r u c t u r e o f t e n a s s o c i a t e d with s a l t accumula-t i o n s i n the s o i l . I t i s unfortunate t h a t p l a n t s do not e x h i b i t d i s t i n c t symptoms of excess s a l i n i t y u nless the s a l t accumu-l a t i o n s are severe. Y i e l d s may be c o n s i d e r a b l y depressed while the p l a n t s r e v e a l no obvious symptoms of d i a g n o s t i c s i g n i f i c a n c e and t h i s f a c t i s apparent from the work of H a r r i s (23) who observed i n 1920 t h a t a l l g r a d a t i o n s from a normal crop to no crop at a l l may be found on s o i l s v a r y i n g i n s a l i n i t y . Osmotic E f f e c t s The o p i n i o n i s h e l d by many workers (19, 26, 37, 38, 41, 66) t h a t the major cause of p l a n t growth i n h i b i t i o n under s a l i n e c o n d i t i o n s i s the h i g h osmotic c o n c e n t r a t i o n o b t a i n i n g i n the growth medium and i t s attendant ef f e c i t s on water ab-s o r p t i o n . T h i s i s i l l u s t r a t e d i n the data of Gau'ch and Magis-ta d (20) who r e p o r t e d a y i e l d r e d u c t i o n of about 10% f o r 4 every increase of one atmosphere concentration for a l f a l f a grown i n sand culture to which sodium chloride was added. It has been shown (65) that the t o t a l stress on the s o i l moisture i n the root zone i s the summation of two forces, the pressure potential (free energy per unit mass developed by a t t r a c t i v e forces between s o i l p a r t i c l e s and the surrounding water) and the osmotic potential (free energy per unit mass due to solutes). As the free energy of the s o i l moisture decreases, whether by increasing mois-ture tension or by increasing osmotic pressure, the d i f f u s i o n pressure d e f i c i t i n the plant root c e l l s must increase to enable the passive entry of water into the plant to continue. In t h i s connection, Wadleigh and Ayers (65) conducted a pot experiment i n which beans were grown in a loam s o i l s a l i n i z e d with various lev e l s of sodium chloride and the plants sub-jected to three moisture regimes. Water was applied to the f i r s t series when the moisture tension had reached 250 cm. of water at the four inch depth (available moisture 50-60f.), to the second series when the tension had reached 750 cm. (available moisture 35-40°/.), and to the t h i r d series upon w i l t i n g of the plants which occurred at a tension i n excess of 800 cm. of water (available moisture 0-10%). The growth and y i e l d of beans was observed to be progressively decreased with progressive additions of sodium chloride. Furthermore, yi e l d s were depressed at higher moisture stresses regardless of whether the stress was due to osmotic forces or to moisture 5. tension (pressure p o t e n t i a l ) . Wadleigh and Ayers conclude that "neutral solutes affect water a v a i l a b i l i t y to plants by means of osmotic forces even when the osmotic'pressure i s only a few atmos-pheres", and they suggest that the hyperbolic nature of a s o i l ' s moisture tension curve accounts for the wide accep-tance of the theory that, for a l l p r a c t i c a l purposes, the s o i l moisture retained between the f i e l d capacity and the permanent w i l t i n g point i s equally available for plant growth. Ayers, et a l (l) i n another paper on the tension experiment just reported point out that root growth i n concentrated s a l t solutions is very slow and the roots be-come rapidl y subernized thus reducing the absorbing area. If roots in the f i e l d do not penetrate new s o i l masses, water absorption i s lim i t e d to areas already occupied. This i n h i b i t i n g action on root extension seriously retards water and nutrient uptake and may be even more important than the direct osmotic effect upon water absorption. The plant i s not s t a t i c and can adapt i t s e l f i n some measure to saline conditions. Eaton (17), working with f i e l d crop plants growing in saline solutions, noticed a marked tendency toward the establishment of an equilibrium between the plant and i t s substrate that i s , increases,, i n the osmotic pressure i n the culture solutions were r e f l e c t e d i n increased osmotic pressure i n expressed tissue f l u i d s . This same phenomenon has been noted by Magistad (37) 6. who interprets i t as an e f f o r t on the part of the plant to maintain an osmotic gradient favorable to water intake. Ha r r i s , et a l (24), i n Utah, likewise observed that the osmotic pressure i n the tissue f l u i d s of plants was re-lated to the s a l i n i t y of the environment i n which they gvevj. They found the osmotic pressure in the expressed tissue f l u i d s of sagebrush, s a l i c o r n i a , and shadscale to be 22, 40, and up to 150 atmospheres respectively. Two sa l t - t o l e r a n t desert shrubs ( a l l e n r o l f i a and sal i c o r n i a ) grew where the s o i l water had an osmotic pressure of JO - 38 atmospheres. Baton (17) feels that some investigators who a t t r i -bute reduced yields under saline conditions to the high os-motic concentrations i n the s o i l solution overlook the fact that plants accumulate s a l t s . This accumulation of sa l t s i n the plant per se i s responsible for the poor growth on saline s o i l s , i n his opinion, but he admits that at higher concen-tr a t i o n s , water uptake might be appreciably slowed down pro-vided the plants were otherwise able to toler a t e the accumu-lated ions." Many other investigations reported i n the l i t e r a t u r e (6, 16, 37, 38, 41, 61, 65) nevertheless have i n d i -cated the close correlation between growth depression and osmotic pressure of the substrate. " C r i t i c a l " Salt Concentration It has long been known that plant species d i f f e r i n t h e i r a b i l i t i e s to withstand concentrations of sa l t i n the s o i l solution. Magistad et a l (38), i n solution culture 7. s t u d i e s found t h a t s a l t t o l e r a n t crops, once e s t a b l i s h e d , could continue growth i n c u l t u r e s having osmotic pre s s u r e s of as h i g h as 6 atmospheres, while s e n s i t i v e p l a n t s ceased growing at 2.5 atmospheres. Other s t u d i e s at the United S t a t e s H e g i o n a l S a l i n i t y -L a b o r a t o r y (6l) i n d i c a t e t h a t sugar beets and milo (amongst the most t o l e r a n t of a g r i c u l t u r a l species)would cease growing at 10-12 atmospheres. I t i s poin t e d out t h a t f a c t o r s other than water r e l a t i o n s must account f o r the c e s s a t i o n of growth s i n c e i t i s g e n e r a l l y b e l i e v e d t h a t permanent w i l t i n g o f p l a n t s does not occur u n t i l a moisture s t r e s s of about 15 atmospheres i s a t t a i n e d . S t u d i e s by Wadleigh and h i s co-workers (67) i n which beans, corn, a l f a l f a and c o t t o n were grown i n loam s o i l i n c r e a s i n g i n s a l i n i t y with depth r e v e a l e d t h a t the os-motic c o n c e n t r a t i o n of the s o i l s o l u t i o n at v a r y i n g depths was remarkably uniform at the time when the p l a n t s began to show d e f i n i t e moisture s t r e s s . They d e f i n e d the c r i t i c a l osmotic pressure of the s o i l s o l u t i o n f o r approximately half-mature p l a n t s to be 7-8 atmospheres f o r beans, 10.5 - 11.5 atmos-pheres f o r corn, 12-13 atmospheres f o r a l f a l f a and 16-17 atmospheres f o r c o t t o n . T h i s i s the same order of r e l a t i v e t o l e r a n c e of these crops as i s g e n e r a l l y found under f i e l d c o ndit i o n s . I n j u r i o u s E f f e c t s of S p e c i f i c S a l t s and Ions Although p h y s i o l o g i c a l drought brought about by 8 excess s a l t s in. the s o i l undoubtedly accounts i n large measure for the poor growth of plants on saline s o i l s , the harmful effects of certa i n ions and s a l t s cannot be dismissed. Thus Harris (23) in 19 20 reported an experiment by Bancroft which showed the following quantities of s a l t s to be toxic to bean plants: , MgCl 2 - 2,6-40 ppm NaCl - 5,660 ppm N a 2 C 0 3 - 2 , 7 1 0 ppm NaHCOj - 1 2 , 3 0 0 ppm When grown in solutions or sand cultures, barley (at the vegetative stage of growth) was found by Magistad (40jf to be more sensitive to calcium chloride than to sodium chloride on an equal osmotic basis. In other sand culture studies with a large number of crops reported e a r l i e r by Magistad et a l ( 3 8 ) chloride and sulphate s a l t s in equal osmotic concentrations caused similar growth reductions with some crops, but chloride sa l t s were s l i g h t l y more injurious with others. S i m i l a r l y , Wadleigh and his co-workers ( 6 4 ) i n studies with guayule noted that growth was better on a s o i l containing .8?. NagSO^' than on the same s o i l to which . 4 f . NaCl was added. Previous studies with t h i s plant ( 6 3 ) had shown i t to be more sensitive to magnesium sa l t s than to calcium s a l t s , f a i r l y s a t i s f a c t o r y groxrth being obtained i n base nutrient solutions adjusted to 3«5 atmospheres concentrations with CaClg, while the plants died in cultures adjusted to 1 . 5 atmospheres with MgClgo Sugar beets responded well to NaCl but only weakly to Na2C0j i n another experiment reported (46). The same investigator found that the tomato plant reacted poorly to carbonate, bicarbonate and sulphatej but produced nearly nor-mal yi e l d s with chloride xirhen sodium was the associated cation (salts added prior to planting at a rate of two and four tons to the acre). Wadleigh (66) reports that the growth of orchard grass was very poor on a loam s o i l to which additions of NagCOj and of Na-HCOj were made; physiological drought did not account for the growth depression, nor was any major derangement in the composition of the grass apparent. Further, a high l e v e l of calcium i n the s o i l solution was shown to be l e t h a l to t h i s grass when supplied as the chloride or n i t r a t e s a l t . Dorph-Petersen (13) reports decreased y i e l d of potatoes when f e r t i l i z e d with NaCl, but explains that the potato i s known to be sensitive to chlor-ion. Canning peas are affected adversely by an abundance of calcium ( 4 4 ) , the peas becoming tougher as t h e i r calcium content increases. That the presence of a nutrient cation in excessive amounts i s harmful to plant growth has long been known (23) and experiments have revealed that by simply increasing the concentration of another cation i n the growth medium, the i n -jurious effects are often lessened or overcome. This phenome-non i s known as ion antagonism and i t s cause is not well understood. Osterhout (23) believes that the explanation may 1 0 • concern membrane permeability (e.g. CaCl2 at low concentration decreases the permeability of the protoplasm while NaCl i n -creases i t ) . Pierre and Bower (45) point out that plant analysis data indicate' that ions present i n very high concen-t r a t i o n i n the nutrient medium depress the absorption of other ions of l i k e charge and may cause a deficiency of the l a t t e r for plant growth. This assertion is apparently borne out in the data of Peterson and Berger (44) respecting the influence of various Ca:Mg r a t i o s oh the y i e l d and quality of canning peas. Sodium Salts Since the e a r l i e s t studies of saline and a l k a l i s o i l s the sodium ion has been singled out for much attention, perhaps because of i t s usual presence in large amounts i n these s o i l s and in vegetation growing on such s o i l s . A l -though high concentrations of the sodium ion are undoubtedly detrimental to s o i l structure and often are associated with an unfavorable pH., the Ha ion i t s e l f does not appear to be unduly toxic to plant growth. Indeed, many experiments in recent years have indicated that Na applications are bene-f i c i a l to a large number of crops under certain circumstances. A recent symposium (5). gives conclusive evidence of i t s use-fulness in t h i s regard. It i s true that Na has not been shown to be an essential element for any crop (even s a l t marsh plants), but i t i s also true that some crops (sugar beets, mangolds) do not produce maximum yields i n i t s absence(53)« 11. Harmer and Benn© (21), who were amongst the f i r s t workers on t h i s continent to become interested in plant-sodium r e l a t i o n s , grew a wide range of crops on a Michigan muck s o i l f e r t i l i z e d with phosphorous and potassium and sodium chloride at various l e v e l s . Salt applications with-out potassium decreased both sugar content and purity of sugar beets, and resulted in a very poor unhealthy growth of table beets, sugar beets and turnips, although the tops of these crops made a somewhat'better growth than the roots. When adequate potassium was supplied, sodium chloride gave appreciable and consistent increases in the yields of table beets, celery, Swiss chard, mangels and sugar beets; c e l e r i a c , cabbage, kale, radishes, kohlrabi and rape y i e l d s generally improved. A number of other crops including barley, carrots, corn, potatoes and tomatoes were not bene-f i t t e d and some sustained actual injury. The following figures extracted from t h e i r data i l l u s t r a t e the benefits of a g r i c u l t u r a l s a l t in sugar beet culture: SUGAR BEETS Sodittm Chloride ft Y i e l d 2 Applied Annually (lbs) Tons Per Acre Roots (Crowned) Tons Per Acre Tops&Crowns Sugar Recoverable 0 7.8 9.6 2,031 500 12.1 14.0 3,305 ft A l l . p l o t s received 600-900 l b s . of 0-8-24 annually k Av. for six years. 12. As a r e s u l t of these studies;, the application of 500-1000 l b s . of a g r i c u l t u r a l s a l t to Michigan muck s o i l s i s recommended for the most s a l t responsive crops, and 100-400 l b s . for the less salt responsive crops. Harmer and Benne (22) have c l a s s i f i e d crops as to t h e i r reaction to applied sodium when potassium i s low 0 and when adequate potassium is present. It i s interesting to observe that with the exception of two species, celery and c e l e r i a c , a l l the crops mentioned in t h e i r c l a s s i f i c a t i o n as deriving benefit from sodium i n a s u f f i c i e n c y of potassium are halophytes. Hartwell and Pember (25) i n solution culture ex-periments conducted in 1907, obtained y i e l d increases with m i l l e t , oats, barley and rye when sodium was added to a potassium-deficient nutrient solution. They explained that sodium could perform some, though not a l l , of the functions of potassium i n some plants at l e a s t . The more recent sugar-beet and mangold experiments of Dorph-Petersen and Steenbjerg (13) i n Europe and of Mullison and Mullison (42) with barley seedlings on t h i s continent lend support to t h i s b e l i e f * The Russian workers, Delemenchuk and Morozov (11) attribute the observed b e n e f i c i a l effect of sodium f e r t i l i -zation on sugar beets to an improved assimilation of n i t r o -gen and phosphorus. Long (6l), on the other hand, states that n i t r a t e nitrogen absorption by plants i s reduced under these circumstances. 13 . Sayre and Shafer (34) corrected hunger signs i n a f i e l d of cannery beets by applying Na and nitrogen; nitrogen alone was i n e f f e c t i v e . They f e l t that the b e n e f i c i a l effect observed was not due to sodium serving as a p a r t i a l s u b s t i -tute for potassium, but was due to the fact that the plants were actually sodium-deficient. J". J . Lehr (35) carried out many experiments in Holland to determine the influence of the sodium ion on plant growth. He, too, holds the view that a more nearly i n -dependent role must be attributed to t h i s ion in the beet, and implies that the proper development of t h i s plant depends as much on sodium as on potassium or calcium. A wealth of other studies reported in the l i t e r a -ture attest to the value of the sodium ion i n plant n u t r i -t i o n . Lunt and Nelson (36) found that sodium i n a potash-deficient s o i l increased the y i e l d of seed cotton by as much as 257', but no y i e l d increase was obtained when adequate le v e l s of potassium were supplied. Holt and Volk (28) re-port y i e l d increases ranging from 17.17° for Austrian winter peas to 185.87« for cotton when sodium was applied as a f e r -t i l i z e r to a number of potassium-deficient s o i l s . In t h i s case, sodium appeared to substitute for potassium, but also had value per se. They claim further that sodium applications may be expected to be b e n e f i c i a l to crops growing on s o i l s which are low i n either sodium or potassium. Solution culture experiments by the Russian workers 1 4 . Butkevich and Maruashvili (8) showed sodium to he b e n e f i c i a l to the y i e l d of corn and wheat up to sodium:potassium r a t i o s of about 5, and complete substitution of potassium by sodium at the time of heading and stalk formation increased the y i e l d of wheat straw and grain as compared to the control re-ceiving only potassium Investigations in Denmark (13) indicate that about three milliequivalents of sodium give the same y i e l d increase with sugar beets as does 1 m.e. of potassium. A certain amount of potassium must of course be present for this e f f e c t to be. r e a l i z e d . In summary, i t seems that a certain amount of sodium in the s o i l i s desirable, i f not e s s e n t i a l . The growth of many crops i s enhanced in the presence of moderate amounts of th i s ion, and the demands on s o i l potassium may be reduced. Ef f e c t of Salt Concentration on Seed Germination Since the germination of seeds i s dependent on water absorption when other factors are favorable, and since absorption of water by plant roots i s retarded by salt con-centrations, i t might be expected that germination of seeds in contact with saline solutions might also be affected. Shive (57) germinated corn and bean seeds in sand supplied with pure salt solutions ranging in concentration from .5-8 atmospheres. Germination was found to be delayed, though not a c t u a l l y prevented by the highest concentrations employed, but damage to the root t i p was evident in concentrations as 15. low as two atmospheres. The percentage of water absorbed by the seed at the time of germination was a l s o markedly reduced at higher c o n c e n t r a t i o n s . On the other hand, U h v i t s ( c i t e d by Kramer (33) ) observed that the higher the osmotic pressure of the s u b s t r a t e , the lower the percentage and the slower the r a t e of germination of a l f a l f a seed. R u d o l f s {52) i n germination t r i a l s s i m i l a r t o Shiv e ' s , found t h a t a b s o r p t i o n , germination, and root growth was reduced at high e r (up to seven atmospheres) concentra-t i o n s , but noted a s t i m u l a t o r y e f f e c t of c e r t a i n s a l t s i n low c o n c e n t r a t i o n s on some seeds. P r e v i o u s soaking i n d i s -t i l l e d water was harmful to the germination of seeds of the species t e s t e d (peas, corn, beans, a l f a l f a ) . I I SALINITY AND SOIL CONDITIONS Chemical E f f e c t s of S a l t s on S o i l s The c o l l o i d a l m a t e r i a l i n s o i l s -- c l a y and organic matter — has the pr o p e r t y of ad s o r b i n g c a t i o n s by f o r c e s of e l e c t r o s t a t i c a t t r a c t i o n . In humid areas the main c a t i o n s i n v o l v e d are H, Ca, Mg,' and to a l e s s e r extent K and Na, and an e q u i l i b r i u m e x i s t s between these ions an the c o l l o i d a l (exchange) m a t e r i a l and i n the s o i l s o l u t i o n . Since the a d s o r p t i o n r e a c t i o n i s r e v e r s i b l e , the r e l a t i v e amount of any p a r t i c u l a r c a t i o n on the exchanger-complex tends to be r e -l a t e d to the r a t i o of t h a t c a t i o n to other c a t i o n s i n the s o i l s o l u t i o n . The u l t i m a t e r a t i o of exchangeable bases plu s 16. hydrogen on the complex i s , however, influenced by differences in replacing power of the ions. The r e l a t i v e replacing power of the ions mentioned i s thought to be as follows ( 5 3 ) : E > Ca = Mg > NH4 - or > K > Na In other words, calcium is more strongly held by s o i l c o l l o i d s than is sodium. The salts carried to the s o i l i n i r r i g a t i o n water w i l l , of course, influence the composition of the s o i l solu-t i o n , and may-be expected to bring about changes in the adsorbed cations. The nature and magnitude of the changes w i l l depend among other things on the cation r a t i o s e x i s t i n g in the c o l l o i d a l complex i n i t i a l l y , and on the composition of the salts present i n the i r r i g a t i o n water. It has been pointed out ( 5 3 , 4-9) that the effe c t i v e concentration of salts in the s o i l solution w i l l not remain the same as that obtaining in the i r r i g a t i o n water, because of the concentra-ti n g effect of evaporation and water absorption by roots, etc., nor w i l l the r e l a t i v e amounts of the various cations remain the same due to p r e c i p i t a t i o n (alkaline earths, par-t i c u l a r l y ) and plant u t i l i z a t i o n . This means that an i r r i -gation water of poor quality when applied to the s o i l can become even more injurious than indicated by i t s analysis. Na and K, being monovalent, are much less strongly held by s o i l s than are the divalent Ca and Mg ions, and for th i s reason the former constitute only a small f r a c t i o n of the t o t a l exchangeable bases in normal f e r t i l e s o i l s of humid 1 7 . r e g i o n s K e l l e y ( 3 1 ) , and K e l l e y , Brown and L i e b i g ( 3 2 ) , s t a t e t h a t when the r a t i o of Na to Ca or to Ca plus Mg i n the s o i l s o l u t i o n does not exceed 2 , l i t t l e danger of accumu-l a t i o n of Na on the exchange m a t e r i a l e x i s t s . As t h i s v alue i s exceeded, Na begins to r e p l a c e other c a t i o n s from the ex-change. Workers at the U.S.D.A. S a l i n i t y L a b o r a t o r y ( 4 9 ) , r e a l i z i n g t h i s , have set the p e r m i s s i b l e l i m i t s of sodium i n i r r i g a t i o n waters at from 6 0 - 7 5 % of the t o t a l c a t i o n s . K e l l e y et a l ( 3 2 ) remark that the s a l t c o n c e n t r a -t i o n i n the s o i l s o l u t i o n i s l i k e l y to become t h r e e to s i x times t h a t of the water a p p l i e d w i t h i n a few days a f t e r i r -r i g a t i o n . At moisture contents near the w i l t i n g p o i n t the c o n c e n t r a t i o n i n the f i l m s surrounding the s o i l p a r t i c l e s may be t e n or more times the i r r i g a t i o n water c o n c e n t r a t i o n . The tendency i s f o r more sodium to be adsorbed as the s o i l d r i e s . They have found a l s o t h a t i f the s o i l i s Ca-saturated, l e s s Na w i l l be adsorbed than i f i t i s Mg-saturated. I f the s o i l s o l u t i o n contains Na and Ca only, l e s s Na i s adsorbed than i f Ca i s r e p l a c e d by Mg. These r e s u l t s are i n agreement wit h the theory concerning the r e l a t i v e r e p l a c i n g powers of the bases. In t h i s connection, Frapps and Fudge ( 5 9 ) observed that t h r e e times as much Ca as Na was adsorbed when a H-saturated c l a y was leached with a s o l u t i o n c o n t a i n i n g e q u i -v a l e n t c o n c e n t r a t i o n s of the two i o n s . 18. The presence of sodium on the exchange comples i n amounts g r e a t e r than.12-15% o f the exchange c a p a c i t y , has been found to r e s u l t i n unfavorable p e r m e a b i l i t y and a e r a -t i o n r e l a t i o n s h i p s i n the s o i l (61, 53)• Campbell and R i c h a r d s ( ? ) , however, suggest that there are i n d i c a t i o n s that s o i l s high i n organic matter may not undergo s t r u c t u r a l breakdown u n t i l higher exchangeable sodium percentages o c c u r . The .work of Thorne (59) on the e f f e c t s of v a r i o u s r a t i o s of exchangeable c a t i o n s on the growth of tomato p l a n t s i n d i c a t e s t h a t y i e l d s are decreased when Na comprises more than 40% of the exchangeable c a t i o n s , but the p l a n t s (tomato) t o l e r a t e 60-70% Na s a t u r a t i o n ( s t r u c t u r a l d e t e r i o r a t i o n a-r i s i n g from the high Na l e v e l was not a f a c t o r i n these ex-p e r i m e n t s ) . Thorne found,, too, that the Ca content of the p l a n t s decreased with i n c r e a s i n g Na on the exchange. Ratner (59) c a r r i e d out s i m i l a r i n v e s t i g a t i o n s i n R u s s i a . He r e p o r t e d t h a t "oats germinated very s l o w l y and d i e d immediately on a s o i l c o n t a i n i n g 71% exchangeable Na, but developed normally and produced w e l l when gypsum, i n amounts p r o p o r t i o n a l to the exchangeable Na, was added to the same s o i l . He d e s c r i b e s f u r t h e r experiments with c e r e a l s t h a t showed that s u b s t i t u t i o n of Ca f o r Na when the l a t t e r made up as.much as 45% of the exchange c a p a c i t y gave no marked i n c r e a s e i n y i e l d s . In Ratner-?s view, a h i g h Na per-centage, w i t h i n l i m i t s , i s not of i t s e l f d e t r i m e n t a l to the normal development of p l a n t s . He e x p l a i n s t h a t , under these circumstances, a v a i l a b l e Ca i s l i k e l y to be very low — a breakdown of the "Ca regime" — and i t i s the u n a v a i l a b i l i t y 19. of Ca which i s large l y responsible for the impaired f e r -t i l i t y of such a s o i l . The same reason i s advanced by Rat-ner for the poor growth observed when Mg constitutes more than 60J. of the exchangeable ions i n a s o i l . S o i l Structure and S a l i n i t y It has- been mentioned that when the sodium ion i s in excess of 12-157- of the exchangeable ions of a s o i l , s t r u c t u r a l deterioration is l i k e l y to become evident. How-ever, i t has been the experience of many workers (12, 18, 37, 46, 68} that a decline i n structure does not occur under these conditions so long as the s o i l solution remains charged with s a l t . The sequence of s o i l changes which occur on de-s a l i n i z a t i o n i s presented by Magistad and Christiansen (39) as follows:-While an abundance of soluble s a l t s remain in a s o i l the c o l l o i d a l clay materials are held more or less ag-gregated, and the s o i l i s s u f f i c i e n t l y porous to permit good percolation and drainage because the Na-saturated co l l o i d s are not able to hydrolyze. But when the solu-ble s a l t s are large l y leached (by r a i n f a l l or good quality water) and i f Ca i s low, the Na clays hydrolyze to form free NaOH, Deflocculation of the c o l l o i d a l par-t i c l e s r e s u l t s , the s o i l becoming sticky, j e l l y - l i k e , and , impenetrable to water. At the same time, organic matter i s dispersed giving a dark brown or black color to the s o i l . The pH of the s o i l often becomes high, so that plant growth i s prevented. Aiyihis stage there i s a tendency for the deflocculated clays to move downward in the p r o f i l e and to c o l l e c t at a lower l e v e l i n the s o i l to form an * a l k a l i - c l a y p a n 1 , leaving a thin layer of somewhat coarser material at^the surface. The clay layer i s very heavy and p l a s t i c when wet and columnar or prismatic when dry. Subsequent leaching leads to the development of a solonetz p r o f i l e with the t y p i c a l rounded-top columnar structure i n the B horizon. The development of this type of p r o f i l e i s bellei-ved by many pedologists to be dependent on high exchangeable Na percentages, but there is some evidence, p a r t i c u l a r l y i n .20. Alberta (53) and elsewhere on t h i s continent, that Mg may-act s i m i l a r l y . The question "Why does a Na-saturated c o l l o i d a l clay system tend to disperse, and in what manner i s an elec-t r o l y t e e f f e c t i v e i n preventing dispersion", can best be an-swered on the basis of zeta p o t e n t i a l . Jenny (see Baver ( 4 ) and Magistad (37) ) explains that when highly hydrated Na ions are drawn to the surface of a negatively-charged clay p a r t i c l e they cannot approach the negative inner layer of the p a r t i c l e as closely as smaller non-hydrated ions (e.g. Calcium). Since the zeta potential i s a function of the average distance of the adsorbed ions from the c r y s t a l l a t -t i c e of the p a r t i c l e , Ha-saturat ion causes a high zeta p o t e n t i a l . This high e l e c t r o k i n e t i c potential on the clay c o l l o i d s causes them to repel each other and dispersion re-s u l t s . I f , however,.the c o l l o i d s come in contact with an el e c t r o l y t e , the layer of adsorbed ions is pressed closer to the p a r t i c l e s , the potential is lowered, and f l o c c u l a t i o n i s achieved. Reclamation of Salted S o i l s Because of the p o s s i b i l i t y that a s a l i n i t y problem may arise i n the Fraser River Delta lands due to the a p p l i -cation of water contaminated with sea s a l t s , i t might be well to examine the problems and solutions arrived at in Europe after much experience with sea-water inundated s o i l s and reclaimed t i d a l lowlands. 2 1 . Westerhof ( 6 8 ) , i n H o l l a n d , r e p o r t s the f o l l o w i n g changes i n the exchange complex of heavy s o i l a f t e r the s o i l had been inundated with sea water f o r more than a year: m.e. /lOOgms. Lutum + Humus (#) Ca Mg K Na ' Normal S o i l 4 8 4 2 1-Inundated S o i l 3 2 1 6 4 1 4 iff-) i . e . percentage f r a c t i o n l e s s than 2 microns . plus percent humus X 3 . I t can be seen that sodium and magnesium r e p l a c e d a l a r g e amount of the calcium. F o l l o w i n g the winter r a i n f a l l (about 1 2 " ) and c o i n c i d e n t a l with the removal of the s o l u b l e s a l t s , p e p t i z a t i o n and d e c l i n e of the s t r u c t u r e becomes apparent. The s o i l i s i n a puddled c o n d i t i o n , drainage i s poor, and a cru s t may form on the s u r f a c e . The h e a v i e r s o i l s undergo " v i c i o u s " s t r u c t u r a l decay on d e s a l t i n g - but a p r o p o r t i o n of humus over 3 If--4% i s u s u a l l y s u f f i c i e n t to prevent t h i s decay. F o r t u n a t e l y , many of these s o i l s c o n t a i n up t o 1 2 % CaCOj and' i n such cases s t r u c t u r a l decay i s very much l e s s pronounced. L i b e r a l a p p l i c a t i o n s of gypsum and shallow c u l t i v a t i o n are recommended to promote exchange of calcium f o r sodium i n the s o i l . Deep c u l t i v a t i o n must be avoided f o r t h e f i r s t few years, s i n c e s o i l below 1 0 cm. depth i s not much a f f e c t e d by the gypsum treatments and i s l i k e l y to p e p t i z e when brought to the s u r f a c e . " Another s t u d y ' i n connection with the r e c l a m a t i o n of the Zuiderzee area, reported'by Zuhr ^ 7 1 ) , shows the s u r f a c e s o i l to 2 0 cm. depth to be s u f f i c i e n t l y f r e e of s a l t to per-22. mit the growth of most crops w i t h i n 2-4 years a f t e r dyking, without s p e c i a l treatment. For i n s t a n c e , a p o l d e r s o i l which contained 22 grams of s a l t s per l i t e r of s o i l moisture was reduced to 2 g / l a f t e r four years under the humid climate of H o l l a n d ( 3 g / l i s the c o n c e n t r a t i o n adopted as the l i m i t of t o l e r a n c e . Good drainage, however, i s e s s e n t i a l . This p a r t i c u l a r s o i l was f r e e of s a l t s a f t e r f i v e y e a r s . S t r u c -t u r a l d i f f i c u l t i e s do not a r i s e i n these s o i l s , even though sodium makes up a l a r g e p r o p o r t i o n of the exchangeable bases. I t i s t h e o r i z e d t h a t b e f o r e drainage, the anaerobic e n v i r o n -ment enables s u l p h a t e - r e d u c i n g b a c t e r i a to o x i d i z e o r g a n i c matter i n the s o i l , u s i ng the gypsum i n the sea water. The sulphate goes through a number of changes and e v e n t u a l l y when the s o i l i s drained, s u l p h u r i c a c i d forms and r e a c t s with CaCOj present, i n the s o i l to form gypsum. Such l a r g e q u a n t i t i e s of gypsum are formed i n t h i s manner that the s o i l s o l u t i o n i s f o r a number of years s a t u r a t e d w i t h t h i s , s a l t , and even when the s o l u b l e sea s a l t s are l a r g e l y r e -moved by l e a c h i n g , enough gypsum i s present to prevent, de-f l o c c u l a t i o n of the aggregates. In a d d i t i o n the high c a l -cium r a t i o i n the s o i l , s o l u t i o n r a p i d l y changes the Na-clay i n t o Ca-clay. The extent of the r e c l a m a t i o n i s apparent from an examination of the f o l l o w i n g figures© 2 ? o Exchangeable Cations i n Surface S o i l C af. Mgf. K_ Na_ Just After Draining 17 35 9 39 Four Years After Ditching(drainage) 7 3 17 5 5 F i n a l 87 8 4 1 Some of the old sea-clay s o i l s ("cat clay") have no CaCOj and are very acid (pH»s of 1 and 2 occur, but 3 aad 4 are more common) because of the H 2 S O 4 production after drainage. These s o i l s contain FeS04, Fe 2(S0 4)"5 + A l 2 ( S 0 4 ) j ^ . . . . in the s o i l solution; hydrolysis of the f e r r i c sulphate occurs and accounts for the lemon-colored basic iron sulphate deposits in cracks and f i s s u r e s . The s o i l s are barren under these conditions, but become somewhat less acid with con-tinued leaching. Hissink ( 2 7 ) presents a similar-picture of the re-clamation process i n the s o i l s of the Netherlands. The fact is stressed that the s o i l must remain permeable and open for reclamation to proceed. This i s p a r t i c u l a r l y important to-wards the end of the salt stage -- i . e . , when the soluble s a l t s are almost completely leached -- so that the products of the exchange reaction (Na) can be removed i n the drainage. He remarks that a young polder s o i l i s l i a b l e to peptize when 1 5 - 2 0 7 ° of the exchange capacity is s a t i s f i e d by Na, and that such a s o i l , even when Na is almost completely leached out, 24. remains e a s i l y peptizable by water. Calcium should be pre-sent in adequate amounts i n the s o i l solution both to replace Na from the exchange complex and to prevent Mg from building up on the exchange complex to the point where s t r u c t u r a l de-t e r i o r a t i o n i s threatened. Other investigations (6, 14) of p a r t i a l l y reclaimed s o i l s have pointed up the fact that the s a l t content i n the surface s o i l may increase appreciably during the growing season, due to the r i s e by c a p i l l a r i t y of salt from the s a l t i e r s u b s o i l . This feature should be considered i n the choosing of crops for these s o i l s . Berg (6) found that 757° of a normal y i e l d of spring barley, sugarbeet, potatoes, peas and beans was obtained when the salt index (grams of NaCl per l i t e r of s o i l moisture) was 10.0, 7.0, 3.0, .6 and .45 res-pectively at the time of planting. The quality, however, in some cases " l e f t a l i t t l e to be desired". It was found (14) that f r u i t trees could be planted on a flooded s o i l after an i n t e r v a l of one winter provided the s o i l was highly permeable. The application of gypsum and barnyard manure and shallow c u l t i v a t i o n together with the right choice of cover crop does much to prevent deterioration of structure i n these s o i l s . In replicated experiments i n Oklahoma with o i l - w e l l brines, P l i c e (46), grew a number of f i e l d crops on l i g h t and heavy s o i l s a r t i f i c i a l l y saliniaed to 1, 3 and 6 tons per acre of NaCl by flooding with brackish water. He observed that 25. seed germination (peas, p a r t i c u l a r l y ) and plant growth was strongly affected by plasmolysis while the sa l t remained in the surface. During the following growing season ( 3 5 " r a i n had f a l l e n in the interval) germination was unaffected and plant yields were almost equal to the controls so long as the plots were not allowed to become dry. P l i c e feels that the induration accompanying the drying of a salt-treated s o i l r e s t r i c t s root ramification and accounts for much of the s a l t damage to plants; damage is also caused by plasmolysis. He further observed that a Na-clay did not reach i t s most extreme induration u n t i l i t s Na content was reduced to approximately the same l e v e l as ob-tained before salt treatment. Apparently a breakdown i n the l a t t i c e structure occurs and t h i s is evidenced by a lowering of the Si02tR 20j r a t i o and by the appearance of large quanti-t i e s of s i l i c a in the leachates. He considers the induration process to be largely one of weak s i l i c i f i c a t i o n . P l i c e found gypsum to be the most e f f i c i e n t and least expensive s o i l addition of several materials tested for reclaiming salt-damaged s o i l s , e specially when used together with manures or other organic matter. Unlike most other i n -vestigators, though, he considers the mechanism of improve-ment by gypsum to be neither chemical nor e l e c t r i c a l , but largel y mechanical.in nature. According to him, microscopic examination of a gypsum-treated s o i l reveals the s o i l p a r t i c l e s to be coated and insulated with t i n y crystals of t h i s mineral, 26. and the lack of cohesiveness between the crystals of gypsum reduces the p l a s t i c i t y and increases the f r i a b i l i t y of the s o i l . This supposedly accounts mainly for the s t r u c t u r a l improvements which follow the application of gypsum. EXPERIMENTAL Project Outline The object of t h i s study was to assess the q u a l i -t a t i v e and quantitative changes in s o i l properties, and the effects on plant response which were l i k e l y to arise when i r r i g a t i o n waters of questionable quality were applied to drops i n the f i e l d . It was hoped that a direct f i e l d approach to the problem would provide many of the answers which were missing, and lead to a better understanding of the factors involvede Accordingly, two farms at Ladner, B. C., both half a mile south of the Trunk Highway on Mathew's Road, were chosen becatise of t h e i r location i n the problem area, and, too, because of the a v a i l a b i l i t y of an extremely saline source of water for the i r r i g a t i o n t r i a l s . Beginning in the year 1950, i r r i g a t i o n water to-t a l l i n g approximately 8 acre inches per year was applied by sprinkler during the growing season to a pasture f i e l d in three equal applications. This procedure was continued during the years 1951 and 1952. This s i t e w i l l be referred to as the "Pasture Plot" i n the ensuing discussion. 27. Pasture Plot S o i l samples for analysis were obtained from f i v e depths at the outset of the t r i a l , both from the area which was to be i r r i g a t e d and from the area which was to serve as a control (no i r r i g a t i o n ) . Water samples were gathered during i r r i g a t i o n s , and s o i l samples from the f i v e depths were also taken within two or three days of each i r r i g a t i o n throughout the t r i a l . In addition, s o i l samples were taken i n the same manner i n the spring so that the leaching e f f e c t s of the winter rains (which amount to some 31" precipitation) could be ascertained. Observations on the appearance and behaviour of the grass species were recorded and grass y i e l d data was ob-tained for the year 1932. Samples of grass from treated- and control areas gathered during the l a s t year of the study were analyzed. A description of the pasture s o i l follows: Depth Texture Organic Matter Percentage # pH 0 - 4" Muck 33.29 5.16 4 - 8" Muck 47 .00 4.29 8-12" S i l t y clay loam 16.43 3.86 12-18" S i l t y clay 16.21 3.57 18-24" S i l t y clay 26.46 3.43 ft- by loss on i g n i t i o n The above figures represent a t y p i c a l sample of the s o i l , but i t is mentioned that s o i l v a r i a b i l i t y within the plot occasioned rather large differences between i n d i v i d u a l 28 samples with, respect to some properties, p a r t i c u l a r l y in the content of organic matter. Discontinuous peat lenses were found at varying depths in t h i s s o i l . The pasture had been seeded down to red clover and timothy eight years prior to the start of the experiment, and had received neither lime nor f e r t i l i z e r during the i n t e r v a l . Cultivated Plot In the spring of 1951 peas and sugar beets were planted in blocks of four rows in an alternate block arrange-ment on another f i e l d (see Plate I ) . This plot i s designated henceforth as the "Cultivated Plot". Half of the planted area was sprinkler i r r i g a t e d with water from the same source, and at the same rate as that used in the pasture study, the remainder of the plot serving as a control (no i r r i g a t i o n ) . The method of s o i l and water sampling adopted here was essen-t i a l l y as outlined in connection with the pasture p l o t . Plant observations were also recorded and samples of plant material were taken for analysis. The plot was seeded to silage corn the following year (1952), i r r i g a t i o n s were continued, and s o i l and water samples and observations on response of the plants were obtained. The properties of the s o i l on which this t r i a l was conducted showed considerably less v a r i a b i l i t y than did the pasture plot s o i l . Some of the properties of this s o i l are l i s t e d i n the following tabulation: Organic Depth Texture Matter % _H 0- 4" Clay Loam 14.27 4.83 4- 8" Clay Loam 13.13 4.54 8-12" S i l t y Clay Loam 8.30 4.05 12-18" S i l t y Clay 7 .00 3.97 18-24" S i l t y Clay 7.65 3.87 This s o i l had been in cultivated crops for at least f i f t e e n years and had received annual applications of 4-10-10 f e r t i l i z e r at a rate of three hundred pounds per acre, plus l i b e r a l amounts of manure, but no lime during t h i s period. Commercial f e r t i l i z e r was not applied i n 1951, the year of the sugar beet-pea study. F i n a l l y , s o i l samples from both the cultivated and pasture plots were taken again in the spring of 1953 to com-plete the f i e l d study. Chemical Prodedures and Methods Certain of the s o i l samples were extracted with neutral normal ammonium acetate, using the methods of Schollenberger and Simon (55), and the exchange capacity de-termined by ammonia d i s t i l l a t i o n , the extract being analysed for Ca and Mg. Hydrogen was also, i n some cases, determined by t i t r a t i o n of the acetate extract. The plant samples were prepared for analysis by grinding, ashing and dissolving the ash in di l u t e HCl, as suggested by Loomis and Shul l (35a). Their procedure for the determination of Ca and Mg in the extract was followed but 30. was modified to permit volumetric rather than gravimetric measurement of the p r e c i p i t a t e s . Sodium and potassium analy-s i s on the same d i l u t e acid extract was accomplished by means of the flame spectrophotometer. In analyzing the i r r i g a t i o n waters, the volumetric procedure of Dobbins and Byrd (5?) for determination of Na in a spdium-zinc-uranyl-acetate p r e c i p i t a t i o n was followed; the constituents Ca, Mg, K, CI, SO4, COj, and HCOj were de-termined by standard procedures as outlined by L. V. Wilcox (70). The pH values reported for the s o i l s were obtained on a saturated s o i l paste by means of the glass electrode potentiometer as recommended by Doughty (15)o The s o i l paste method gives values which are f a i r l y close to that found at the moisture equivalent (15) and minimizes errors due to hydrolysis attendant on higher soil:water ratios? This is p a r t i c u l a r l y important when working with saline s o i l s . The Beckman Model D. U. Quartz Spectrophotometer with the 10,300 Flame Attachment u t i l i z i n g propane gas was used i n the determination of Na and K as noted above. A graph was prepared from l i g h t emission values obtained for a series of concentrations of the element i n question; the emission percentages for "unknown" samples were then referred to t h i s graph and the concentration of the element interpolated. The standard and "unknown" solutions a l i k e were IN. with respect to ammonium acetate. These solutions were 33!.. analyzed d i r e c t l y i n the flame. A somewhat s i m i l a r t e c h -nique was employed by the New Zealand workers, Swindale and F i e l d e s (60) i n the determination of K i n s o i l e x t r a c t s , and by Myers et a l (43) i n a n a l y z i n g p l a n t and s o i l samples f o r K and Na with r e p o r t e d l y good r e s u l t s . A c c o r d i n g t o Barnes et a l ( 2 ) , flame photometric procedures y i e l d r e s u l t s which i n most cases are "equal to or b e t t e r than those given by standard chemical methods*'. The procedure f o l l o w e d f o r a "run" was t o f i r s t atomize and determine the emission percentages f o r a s e r i e s of standard s o l u t i o n s , checking the readings obtained a g a i n s t the p r e v i o u s l y prepared standard curve r e f e r r e d t o above. Adjustments to the s e t t i n g s of the instrument were made un-t i l the readings obtained corresponded to those used i n the p r e p a r a t i o n of the standard graph. The "unknown" s o l u t i o n c o n c e n t r a t i o n was then determined by a " b r a c k e t t i n g " proce-dure -- i . e . , each sample rea d i n g was preceded by, and f o l l o w e d by a r e a d i n g f o r a standard of known concentratiO°n, sma l l s e t t i n g adjustments being made where necessary to ma i n t a i n the standard readings i n conformity with- the standard graph. P r e l i m i n a r y study r e v e a l e d t h a t the presence of K at the c o n c e n t r a t i o n s present i n tithe s o i l e x t r a c t s had a n e g l i g i b l e e f f e c t on the emission i n t e n s i t y of the Na present i n the e x t r a c t . The Na present did i n t e r f e r e with the.K rea d i n g s , however, and n e c e s s i t a t e d the a d d i t i o n of Na at v a r y i n g l e v e l s to the K standards. The s e r i e s of K standard curves r e s u l t i n g were p l o t t e d on one graph e n a b l i n g extrapo-32. l a t i o n of an accurate K value for a solution the Na concen-t r a t i o n of which had previously been determined. Other ions present i n the extracts, after some investigation, were f e l t to have l i t t l e influence on the accuracy of the Na and K deter-mination. Studies show that the e l e c t r i c a l conductivity of saline s o i l extracts i s closely related to plant response on such s o i l s ( 6 l , 4 9 ) « This r e l a t i o n s h i p i s to be expected, since conductivity is a function of ion concentration, which, i n turn, determines the osmotic pressure of the solution. Conductivity determinations on s o i l pastes are unreliable ( 4 8 ) and readings are therefore often made on the s o i l extract obtained from a saturated s o i l . This method has the disadvantage that a rather large sample of s o i l must be used to provide s u f f i c i e n t extract for the determination, and i t is also tedious and time-consuming. Even though less precise results are obtained at higher soilrwater r a t i o s , for p r a c t i c a l work this method is quite s a t i s f a c t o r y . The e l e c t r i c a l conductivity values reported i n t h i s paper were obtained with a Solu-Bridge (Industrial Instru-ments model RD 2 6 ) on the supernatant of 1 : 5 soil:water mixture prepared in much the same manner as outlined by Wilcox (69} st Summerland, B. C., with the exception that he used a d i l u t i o n equal to f i v e times the moisture-holding capacity. The high d i l u t i o n used was made necessary by the limited conductivity range of the instrument and by the high s a l i n i t i e s encountered. Though higher d i l u t i o n s are considered 33. objectionable because of the p o s s i b i l i t y of bringing into solution solid-phase s a l t s , the absence of carbonates and preponderance of very soluble s a l t s in these s o i l s seemed to j u s t i f y the technique used. It was found that the conductivity of the super-natant was increased s l i g h t l y by f i l t e r i n g before determina-t i o n as mentioned by Wilcox, but not s u f f i c i e n t l y so to materially a l t e r the readings. Wilcox made no attempt to con-vert readings into terms of parts per m i l l i o n s a l t s , and the conversion is not attempted in the present instance. Physical Methods Several days afte r the last application of water to the pasture and cultivated plots, s o i l core samples for porosity relationship studies were taken in brass cylinders with a s p e c i a l l y designed sampling t o o l and pore size d i s -t r i b u t i o n obtained by means of the tension table described by Learner and Shaw (34). The cores were subjected to three moisture tensions -- 20, 40, and 60 cm. of water — and weighed when equilibrium was attained. Following the porosity studies, percolation rate determinations were made us'ing the same s o i l cores. The s o i l cores were f i r s t allowed to soak overnight, then transferred to a large Buchner funnel and a brass ring of the same diameter as that of the core retaining r i n g affixed to the top of the core. By so extending the brass core, i t xnras possible to main-t a i n a hydraulic head of ha l f an inch of xvater on the surface 34 . of the s o i l core. The apparatus was arranged so that the drainage could be conveniently collected and measured at one-half or one hour i n t e r v a l s . Measurement of percolates was continued for a period of ten hours. E l e c t r i c a l conducti-v i t y of leachates so obtained was determined at the same time* The w i l t i n g point percentage for the s o i l s reported was approximated by the technique of Richards (50) i n which the moist s o i l i s brought to equilibrium with a pressure of 15 atmospheres i n a s p e c i a l l y designed chamber which permits moisture to escape. The moisture content of the s o i l when outflow from the chamber ceases closely approximates the permanent wi l t i n g point. Richards and Weaver (51) showed that the "15 atmospheres percentage" for 102 of 119 s o i l s tested was within 1.57» below the true permanent w i l t i n g per-centage as determined by conventional methods. Moisture equivalent values for the s o i l s were ob-tained by the standard centrifuge procedure as outlined by Veihmeyer and Hendrickson (62). This determination provides a f a i r measure of the f i e l d capacity for heavy-textured s o i l s , but not necessarily for sands. V i a b i l i t y tests on the pea seed from the f i e l d plots were conducted i n the following manner. F i f t y pea seeds from each treatment ( i r r i g a t e d and control) were placed on a mat of glass wool in the bottom of a desiccator. Three desic-cators were prepared in t h i s way; one was supplied with enough d i s t i l l e d water to p a r t i a l l y immerse the seeds, the other two 35. being s i m i l a r l y supplied with, diluted i r r i g a t i o n water having e l e c t r i c a l conductivities of 7 and 13,8 millimhos respec-t i v e l y . The osmotic concentration of the l a t t e r two solu-tions i s calculated to be approximately and 5 atmospheres on the basis of t h e i r conductivity values (6l) and on data from the International C r i t i c a l Tables as presented by Magis-tad and Christiansen (39). After twenty four hours had elapsed, the excess water was drawn o f f by pipette to leave the seeds almost free of immersion. The desiccator was closed s u f f i c i e n t l y to prevent further concentration of the saline solutions by evaporation while permitting adequate interchange of a i r . The temperature was maintained at 68°1? 1 3* « Germination counts were taken d a i l y for eight days after which time no further germination occurred. RESULTS AND DISCUSSION I r r i g a t i o n Water Analysis Analysis of the i r r i g a t i o n waters used on the pas-ture and on the cultivated plot during the term of the ex-periment i s compared to Dittmar's average for ocean waters (59) in Table I. TABLE I COMPOSITION OF IRRIGATION WATERS E q u i v a l e n t s per M i l l i o n P a r t s T o t a l Na K Ca Mg 01 s o 4 C0 ? HCO, 3 T o t a l Cations T o t a l Anions S a l t s . p.p.m. Pasture P l o t I r r i g a t i o n Water # 186.? 3.91 5.02 40.10 203.0 17.42 .9 .13 325.8 221.5 13,121 C u l t i v a t e d P l o t i I r r i g a t i o n 'Water / 193.5 4.03 4.70 41.2 210.9 17.90 1.0 .15 243.4 230.0 13,577 : i l : l D i l u t e d Sea Water TL 232.5 4.54 L1.00 53.3 280.0 28 .05 1.2 17,500 / Average f o r two years of experiment S Dittmar's average X 1/2 to f a c i l i t a t e comparison O S 3 7 . I t i s evident that the waters used f o r i r r i g a t i o n i n these s t u d i e s d i f f e r l i t t l e from sea water except i n the matter of c o n c e n t r a t i o n . The source of the i r r i g a t i o n water was an open drainage d i t c h emptying i n t o Mud Bay, but xvhich permitted i n g r e s s of b r a c k i s h waters at high t i d e . The d r a i n -age water present i n the d i t c h would be expected to a l t e r both the composition and c o n c e n t r a t i o n of the sea water en-t e r i n g the d i t c h and t h i s accounts f o r the d i f f e r e n c e s ob-served i n Table I . Furthermore, the sea water i n the Mud. Bay b a s i n i n d i l u t e d by the waters of two surface streams, the Nicomekl and Serpentine r i v e r s , which empty i n t o t h i s b a s i n and so does not i n i t i a l l y have a c o n c e n t r a t i o n of 35 ,000 ppm as does an average sea water sample. The percent sodium (m.e. Na d i v i d e d by the t o t a l m.e. c a t i o n s and expressed as a percentage) i n the waters used f o r i r r i g a t i o n i s 79-31°, while t h a t of sea water i s 7 6 . 7 7 ° ; the r a t i o of Na:Ca+Mg i s 4.2 :1 and 3 . 6 : 1 r e s p e c t i v e l y . In ad-d i t i o n , the pH values of the two water sources are s i m i l a r , ( 8 . 7 and 8 . 5 ) i n d i c a t i n g with c e r t a i n t y t hat sea-water contamination i s r e s p o n s i b l e f o r t h e high s a l i n i t y of the i r r i g a t i o n waters. It i s c a l c u l a t e d t h a t the amount of water a p p l i e d a n n u a l l y (8 acre inches) would convey d i s s o l v e d s a l t s to the p l o t s at the r a t e of 12 tons per a c r e . Of i n t e r e s t i s the f a c t that i f a l l t h i s s a l t remained i n the s u r f a c e foot of s o i l , the s a l t c o n c e n t r a t i o n would, exceed . 6 % a f t e r one season of i r r i g a t i o n . This s o i l would then be of "medium 38. strong" s a l i n i t y according to the c l a s s i f i c a t i o n of Kearney and S c o f i e l d (see 39). Magistad and Christiansen (39) have defined as i n -jurious to unsatisfactory i r r i g a t i o n waters having a t o t a l s a l t content of 2000 ppm, a sodium content in excess of 75f°, or con-taining 2 ppm boron. Since the boron content of sea water (3) i s 4.6 ppm, the i r r i g a t i o n waters applied could well have contained upwards of 1.3 ppm. Therefore, on the basis of these three standards, the waters applied to the plots were of unsatisfactory quality. S o i l Analyses i Pasture Plot It i s mentioned in connection with the s o i l analysis data that the values reported were obtained from an analysis of 'single samples only. The usual sampling procedure -- that of compositing numerous s o i l samples to ensure a representative sample — would have reduced the errors in the data due to s o i l v a r i a b i l i t y , but would also have limited appreciably the scope of the work. In the interpretation of the data, therefore, trends are f e l t to be more s i g n i f i c a n t than are differences between individual samples. The salt content of each s o i l is reported in terms of "cations extractable with ammonium acetate" and i t is to be observed that these values include both exchangeable cations and soluble cations. The s o i l samples taken following the winter rains were found to be e s s e n t i a l l y free of soluble s a l t s , 39. however, and analyses of these B o i l s should r e f l e c t the changes i n the c a t i o n r a t i o s on the exchange complex r e s u l t -ing from the treatments. F i g u r e I presents g r a p h i c a l l y the changes i n the pasture s o i l content of Na, K, Ca and Mg brought about by i r r i g a t i o n with the water used. An examination of the graph r e v e a l s no s i g n i f i c a n t chan'ge i n the Na content of the s o i l f o l l o w i n g the f i r s t a p p l i c a t i o n of the high-Na water. One would c e r t a i n l y expect an i n c r e a s e , and i t i s suspected t h a t an e r r o r i n l a b e l l i n g o c c u r r e d . In t h i s event, the r e p o r t e d values f o r t h i s p a r t i c u l a r sample would be i n v a l i d a t e d . Un-f o r t u n a t e l y , seven inches of r a i n had f a l l e n between the time of a p p l i c a t i o n of the t h i r d i r r i g a t i o n of 1951 and the pro-c u r i n g of the s o i l sample which was analyzed to a p p r a i s e the e f f e c t s of t h i s i r r i g a t i o n , The observed drop i n the Na con-tent of the s o i l at t h i s point i s a p p a r e n t l y due to the l e a c h i n g E f f e c t ofthe r a i n . The exchange c a p a c i t y of the s o i l to four inch depth averages 67.42 m.e./lOOg. At t h e outset of the t r i a l , Ca comprised 41% of the exchangeable ions i n the s o i l . A f t e r i r r i g a t i o n f o r one, two and t h r e e years, Ca on the exchange complex was reduced to 3 6 , 1 7 , and 19% r e s p e c t i v e l y . I t ap-pears t h a t the p e r c o l a t i n g high Na i r r i g a t i o n water removes Ca from the s o i l , c a r r y i n g i t downwards i n the p r o f i l e . Over the winter, when p r e c i p i t a t i o n i s e x c e s s i v e and d u r i n g which time t h i s s o i l i s subjected to continuous washing by a f l u c t u a t i n g water table ' w h i c h f l o o d s the s u r f a c e at times, 40. 28 26 j24 o CO I 22 O 20 cn SI8 < or e> 16 2 14 12 10 CO I-ui 8 > 6 ^ 4 AVERAGE EXCHANGE CAPACITY 67.42 m.e;/\00 gms. soil RIOINAL SOIL 1950 IRRI9ATI0N |$T• • • ; : 2>» .:: 31 * :: .WIN.tER;;: •:|'T:::: i :2»*: f:;:3**>"::. WINTER IRRIGATION 4 8T IRRIOATION AFTER 2«0 :3m WINTER 1951 FIG. I INFLUENCE OF SALINE IRRIOATION WATER AND WINTER LEACHING ON CATIONS EXTRACTABLE WITH NH4OAc IN SURFACE SOIL (0-4") OF PASTURE PLOT. 41. calcium is observed in two instances to p a r t i a l l y regain i t s r e l a t i v e position on the exchange material. The reason for the p a r t i a l build-up of calcium during t h i s season is not clear, but i t i s possible that calcium present in the water bathing the s o i l may effect the change, since i t is known that t h i s ion is normally the dominant basic ion i n the drainage waters. It may be that the calcium removed from the surface by the i r r i g a t i o n water accumulates at a lower l e v e l in the s o i l and is carried back to the surface with the r i s i n g water table. B i o l o g i c a l decomposition i n the s o i l may, too, assist in accounting for the peculiar behaviour of c a l -cium. Whatever the explanation, t h i s effect i s not considered to be p a r t i c u l a r l y s i g n i f i c a n t . More notable i s the fact that the calcium content of the soil,has, on the whole, been markedly diminished by the i r r i g a t i o n treatments. A similar picture of the behaviour of calcium is evident in the data (Appendix) for the 4-8" horizon, although the extent of the removal of t h i s ion i s not as marked (21.2% of the exchange capacity o r i g i n a l l y , 17.8% at the termination of the experiment). The percentage Ca on the c o l l o i d a l com-plex at the 8-12" depth is also d e f i n i t e l y reduced by the treatment,. The Na content of the s o i l , on the other hand, i s shown to increase markedly during the i r r i g a t i o n s as xvould be anticipated. The effects of leaching winter rains on the re-moval of these accumulated sodium salts is c l e a r l y demonstrated and i t is remarkable that the Na ion has increased b^ b very l i t t l e 42. i t s percentage on the exchange complex during the course of the i r r i g a t i o n s . These s o i l s contain a high proportion of exchangeable hydrogen (57.4% average) as is evident from the pH values, and this ion is d i f f i c u l t l y replaceable, e s p e c i a l l y by an ion with a comparatively weak replacing power such as sodium. It i s believed that the preponderance of Na" in the s o i l solution has caused the Ca l e v e l in the s o i l to drop to the point where Ca is so strongly held that further replacement by the weak Na ion becomes increasingly d i f f i c u l t and that the presence of the strongly held hydrogen ion in such large amounts on the exchange material prevents the Na ion from replacing the l a t t e r to any great extent. The nature of the Na curve also suggests that an equilibrium between the s o i l and the tr e a t -ment has perhaps been attained and that further i r r i g a t i o n s , though they may eventually increase the sodium percentage to an injurious l e v e l , would require many years to do so. The f a i l u r e of Na to continue to build up appreciably on the exchange complex in successive i r r i g a t i o n s after the i n i t i a l r i s e following the 1950 treatment i s also demonstrated by the data for the s o i l samples taken from the 4-8" and 8-12" depths as presented in Table I I . The Na analysis of the 0-4" layer of s o i l i s included for comparative purposes. 43 TABLE II PASTURE SOIL CONTENT OP SODIUM AS INFLUENCED BY IRRIGATION Na i n m.e./lOOg. s o i l Depth S p r i n g 1950 S p r i n g 1951 S p r i n g 1952 S p r i n g 1953 Before Treatment 0-4" 1.98 ( . 3 6 k 3.26 ( .27) 4.63 ( .36) 3.48 ( .23) 4-8" 1.75 (.54) 3.41 ( .28) 3.59 ( .38) 3.45 ( .25) B-12" 3.63 ( .88) 3.49 ( .50) 5.40 ( .94) 4.24 ( .53) j E l e c t r i c a l c o n d u c t i v i t y i n m i l l i m h o s of 1:5 e x t r a c t of s o i l i n d i c a t e d by b r a c k e t t e d f i g u r e s . The e l e c t r i c a l c o n d u c t i v i t y values f o r the s o i l samples have a l s o been recorded i n the t a b l e . The c o n d u c t i v i t y values of the 8-12" l a y e r of s o i l i n d i c a t e by t h e i r magni-tude th e presence of s m a l l amounts of s o l u b l e s a l t s which, however, would not m a t e r i a l l y a l t e r the i n t e r p r e t a t i o n of the data. The s o i l content of Mg has been r a i s e d from 4.3% to a v a l u e of 8% of the exchange c a p a c i t y . T h i s i n c r e a s e i s not s u r p r i s i n g i n view of the f a c t t h at Mg makes up 17% of the c a t i o n s i n the i r r i g a t i o n water. But here too, the Mg content seems to have l e v e l l e d o f f i n much the same way as has Na, and f u r t h e r a p p r e c i a b l e i n c r e a s e s i n Mg under continued i r -r i g a t i o n s are not a n t i c i p a t e d f o r many years at l e a s t . In g e n e r a l , s o i l K i s v e r y l i t t l e a f f e c t e d by the 44. treatment, except for a sli g h t increase following the i r r i g a -tions which is attributed to the small amount of K carried to the s o i l i n the i r r i g a t i o n water. The winter rains apparently remove t h i s accumulation, leaving the s o i l with a small but constant amount of th i s element. The effect of the i r r i g a t i o n treatment on the ver-t i c a l d i s t r i b u t i o n of sa l t s i n the p r o f i l e i s r e f l e c t e d i n the data presented i n table III for Na content of the s o i l and e l e c t r i c a l conductivity of the 1:5 s o i l extracts. TABLE III VERTICAL DISTRIBUTION OF SALTS IN PROFILE OF PASTURE PLOT AS AFFECTED BY APPLICATIONS OF SALINE WATER Na i n mg./lOO gm s o i l / Depth Spring 1952 E . C . i n mmhos Aft e r F i r s t I r r i g . 1952 B . C . i n mmhos After Second I r r i g . 1952 B . C . i n mmhos. lifter Phird I r r i g 1952 B . C . 1 in mmhos Spring 1953 B . C . i n ramhos 0 -4" L06.5 .36 189.8 .98 216.8 1.4.7 255.1 1.84 80.1 • 23 4-8 " 82.5 .38 127.7 .59 183.4 1.36 308.9 2 .05 79.4 .25 8-12" 124.1 .94 137.7 1.09 339.3 2.72 289.4 2.74 97.5 .53 12-18" 93.4 1.02 124.3 1.28 282.2 2.63 283.8 2.77 99.7 .80 18-24" i72.4 5 . 0 0 203.6 2.07 413.1 3 .80 313.2 3.05 524.3 2.80 7 See Appendix for more complete analysis The e l e c t r i c a l conductivity values serve as an approxi-mate check on the accuracy of the analyses and are seen to 45. correlate rather well with the Na content (although other ions present in the s o i l and not reported in the above table would also contribute to the e l e c t r o l y t i c properties of the extr a c t ) . Examination of Table III reveals that the s a l t content of the s o i l to a depth of 18 M i s greatly increased by i r r i g a t i o n with the saline water, and that the build-up pro-gress with the number of increments of water applied. The concentration of s a l t s i n the 18-24" layer is e r r a t i c because of the presence of a fluctuating water table which, at times, even during the growing season approaches to within approxi-mately 21" of the s o i l surface. The removal of accumulated s a l t s from the s o i l by the dormant season rains i s s t r i k i n g l y i l l u s t r a t e d i n the data, also. The estimated osmotic pressure exi s t i n g i n the s o i l solution of the pasture s o i l following the t h i r d i r r i g a t i o n of 1950 i s presented i n Table IV. The reported values were calculated from the conductivity-osmotic pressure r e l a t i o n -ship data established by workers at the U.S.D.A. S a l i n i t y Laboratory (49), using the determined values for e l e c t r i c a l conductivity of the s o i l extract*omoisture equivalent per-centage and w i l t i n g point (15 atmospheres) percentage of the s o i l samples. Osmotic pressure values for the non-irrigated soil;; are included for comparison. 46. TABLE IV CALCULATED OSMOTIC PRESSURE OF SOIL SOLUTION AT THE MOISTURE EQUIVALENT PERCENTAGE. AND AT THE 15 ATMOSPHERE PERCENTAGE DEPTH M 0E. % "15 ATMOSPHERE" )SMOTIC PRESSURE IN ATMOSPHERES 3ontrol S o i l at Irri g a t e d S o i l at M.E, P.W.P. - M.E. - P.W.Po 0- 4" 52.8 27.5 < 1 1.7 7.0 12.7 4- 8" 54.4 3G.5 1.4 2.2 4.9 7.8 8-12" 57.3 29.8 2.1 3.7 9.8 17.2 I12-18" 46.6 20.6 6.1 11.3 10.4 21.5 18-24" 50.1 27.6 11.2 21.5 9*9 16.2 # Approximately the w i l t i n g point percentage These figures show that the control s o i l to a depth of.12" i s r e l a t i v e l y free of soluble s a l t s , but below t h i s depth considerable s a l t i s present. The pasture plot i s bordered by the drainage d i t c h from which the i r r i g a t i o n water was obtained, and i t appears that saline water intrudes from t h i s ditch into the porous subsoil of the pasture, ac-counting for the s a l i n i t y . (As mentioned before, free water has been observed i n thi s s o i l at a depth of as l i t t l e as 21" even during the dry summer weather.) V i r t u a l l y a l l of the water present i n the surface foot of s o i l would remain a v a i l a -ble down to the determined w i l t i n g point because of the low osmotic concentration of the solution i n the wilt i n g range© The osmotic pressure i n the s o i l solution of the i r r i g a t e d s o i l , on the other hand, i s quite high throughout 47. the whole of the p r o f i l e . It i s obvious that much of the water contained by this s o i l between the moisture equivalent percentage and the "permanent wil t i n g point" (as determined by pressure extraction) would not a c t u a l l y be available to plants, and that permanent w i l t i n g would occur at considerably higher moisture contents than those indicated by the 15 at-mosphere percentage. Indeed, the moisture stress on the plant is quite considerable even at the moisture equivalent percentage and i t i s notable that r e l a t i v e l y high solution os-motic pressures exist throughout the whole of the root zone i n the pasture (depth of rooting was observed to be 12-14"). The f i e l d moisture content would normally be some-what higher than that indicated by the moisture equivalent percentage, however, because of the high water table. Con-sequently, the solution concentration would also be more di l u t e than shown, although appreciable osmotic pressure stresses would s t i l l e x i s t . By keeping the s o i l in a moist condition by i r r i g a t i n g frequently, the osmotic stress could be maintained at a moderate l e v e l , thus reducing the danger of physiological drought. Figure II records graphically the pH values for s o i l samples from five depths taken i n the spring, and after successive i r r i g a t i o n s for the three years of the t r i a l . The s o i l pH i n the surface 8" ranges between 4 and 5.4, with the surface 4" tending to be s l i g h t l y less acid than the underlying 4". Between 8" and 24" depth the s o i l has 49. a pH in the range 3.5-4, the layers becoming more acid with depth. This s o i l contains large quantities of raw organic matter from which acids may originate to account for the low pH's observed. That the s o i l is less acid in the surface than in the subsoil appears to be anomalous, when considering the reaction i n the leached p r o f i l e of an upland s o i l . But the Delta s o i l s have a high water table and the subsoil i s con-sequently more moist, a condition which is conducive to reducing conditions and the production of s o i l a c i d i t y . Furthermore, bases leached from the surface s o i l would not l i k e l y accumulate in the subsoil because of the fluc t u a t i n g water table. In the l i g h t of these considerations, the anoma is perhaps only apparent. Some rather large aberrations are observed in the pH values of the s o i l samples and of those taken aft e r each i r r i g a t i o n p a r t i c u l a r l y . Whether sampling error is responsi-ble for these departures or whether they are due to some other cause i s not known. In general, i t may be said that the pH i s lower •V* in the f a l l than in the spring, as is usually the case i n i-s o i l s . Regarding the 0-4" s o i l layer, no p a r t i c u l a r change in the s o i l pH i s evidenced by the data a f t e r three years of the treatment. In the 4-8" layer, only a small change i n the pH of the 1953 spring sample as compared to the o r i g i n a l s o i l i s seen, and the evidence of the significance of th i s change 5 0 . 1 i s inconclusive. In the deeper layers, only small changes have occurred, and these are probably i n s i g n i f i c a n t . The results of the porosity studies on the pasture s o i l are set down i n Table V. Cores were taken i n quadru-pl i c a t e from the surface s o i l of the pasture i n the f a l l of 1 9 5 2 (after three year's i r r i g a t i o n s ) for the tension table measurements. TABLE 7 POROSITY DETERMINATIONS ON THE PASTURE SOIL lo Porosity at Tension of Total Volume )-20cm. 0-40cm. 0 - 6 0 c m . Porosity Weight Control S o i l (1 - 5 " ) # 10 .7 15.2 14.2 66.4 . 7 0 Irrigated S o i l (1 - 5 " ) # 11 .9 14.2 15.1 70 .9 . 6 8 f- Average for 4 cores The tension table results reveal that no s t r u c t u r a l change of any significance has resulted from the application of the saline i r r i g a t i o n water, the comparable values for the three tensions being similar and quite within the l i m i t s of error of the method used in t h e i r determination. The t o t a l porosity, too, i s not adversely affected by the treatment, the difference between the two treatments 5 being small and l i k e l y i n s i g n i f i c a n t . The high organic matter content and the high t o t a l porosity of these s o i l s is indicated by the low volume weight figures. In Table VI, percolation rate determinations are recorded for the above s o i l cores. The amount of percolate 51. was measured hour l y , and the values are r e p o r t e d f o r the t h i r d , seventh and t e n t h hour of continuous p e r c o l a t i o n . TABLE VI PERCOLATION RATES FOR PASTURE SOIL Inches per Hour 3rd Hour 7th hour 10th hour C o n t r o l S o i l (1-5" ) 6.08 5.77 5.84 I r r i g a t e d S o i l (1-5" ) 5.90 4.65 4.11 The s o i l i s e x c e p t i o n a l l y permeable, s i n c e a per-c o l a t i o n r a t e of g r e a t e r than 1" per hour i s considered to be good (58). The p e r c o l a t i o n r a t e of the i r r i g a t e d s o i l decreases somewhat more than does t h a t of the c o n t r o l s o i l under continuous percolatio£j and although t h i s i s not con-s i d e r e d important, i t may be t h a t some d i s p e r s i o n occurs as the s a l t (with i t s d e s p r e s s i o n e f f e c t ) is. leached out of the s o i l . The water used i n the p e r c o l a t i o n determinations had a very low s a l t c o n c e n t r a t i o n (tap water) and i t i s point e d out by Fireman (18) that p e r c o l a t i o n r a t e s should be determined using the water o r d i n a r i l y used i n i r r i g a t i o n p r a c t i c e on the s o i l under study, because the use of a water with a low e l e c t r o l y t e content may give erroneous r e s u l t s with some s o i l s , i i C u l t i v a t e d P l o t The i n f l u e n c e of the i r r i g a t i o n treatments on the surf a c e (0-4") s o i l content of the ions Na, K, Ca and Mg i n 52. the c u l t i v a t e d p l o t i s presented i n F i g u r e I I I . Calcium does not appear to be removed from the s u r f a c e d u r i n g the i r r i g a -t i o n s (though some exchange undoubtedly would have occurred) but f o l l o w i n g the subsequent winter r a i n s l o s s of Ca i s e v i d e n t . Thus t h e p p e r c e n t a g e of t h e t o t a l exchangeable ions occupied by Ca was reduced from 28.1% to 19.8% a f t e r one year's i r r i -g a t i o n with the s a l i n e water, with a f u r t h e r small r e d u c t i o n to 18% a f t e r i r r i g a t i o n f o r two years. The s o i l at the 4-8" depth l o s t calcium a l s o . The comparable f i g u r e s f o r t h i s h o r i z o n are: i n i t i a l l y 24.5%; a f t e r one and two years i r r i g a -t i o n 18.9% a n d 19.8% r e s p e c t i v e l y . The i n t e r p r e t a t i o n of the Ca a n a l y s i s f o r the deeper l a y e r s i s d i f f i c u l t because of the presence of s o l u b l e s a l t s , but i t may be remarked that the t o t a l calcium seems to have been i n c r e a s e d s l i g h t l y i n these l a y e r s , although there has been an o v e r a l l l o s s of Ca from the s o i l . This w i l l be evident from the data as presented i n Table VII. TABLE VII CALCIUM CONTENT OF CULTIVATED SOIL AT VARIOUS DEPTHS AS INFLUENCED BY IRRIGATION E x t r a c t a b l e Ca i n m.e./lOO g. Depth S o i l Before Treatment 1951 S o i l A f t e r I r r i g a t i o n f o r 1 year S o i l A f t e r I r r i g a t i o n f o r 2 years 0- 4" 12.1 7 .-° 7.0 4- 8" 10.0 6.0 7.4 8-12" 2.0 2.3 5.0. 12-18" 1.3 1.9 18-24" .9 1.6 FIG.SE INFLUENCE OF SALINE IRRIGATION WATER AND WINTER LEACHING ON CATIONS EXTRACTABLE WITH NH40Ac IN SURFACE SOIL (0-4") OF CULTIVATED PLOT. 54. A remarkable accumulation of sodium sal t s i n the surface s o i l of the cultivated plots resulted from the i r r i -gation treatment (see Figure I I I ) , and here, too, as in the pasture s o i l , a large part of the Na was leached out during the rainy season. Unlike the pasture s o i l , though, the Na percentage of thi s s o i l apparently continues to b u i l d up each year. Thus the Na content was increased from an i n i t i a l 2.1% of the exchange capacity to 6,0% after one year's i r r i g a t i o n , and to 14.l7« after two year's treatment with the i r r i g a t i o n water. There is evidence that further i r r i g a t i o n with such a water would increase the sodium percentage s t i l l more and eventually lead to pronounced s t r u c t u r a l decay, since i t i s seen that the s o i l has already reached the 12-15$ exchange-able Na l e v e l generally associated with deflocculation and dispersion of s o i l c o l l o i d s . The exchangeable sodium content of the 4-8" s o i l layer undergoes a similar marked increase, the percent sodi-um i n i t i a l l y and after one and two year's i r r i g a t i o n being 2.0%, 7o3% and 17.2% respectively. The changes i n the ex-change complex below 8" depth are not discernible because of the presence of soluble s a l t s (see Table VII I ) . Why the Na percentage should continue to increase under i r r i g a t i o n in t h i s s o i l and not i n the pasture s o i l i s not d e f i n i t e l y known. The cultivated s o i l , though, was more elevated i n aspect and consequently did not undergo continuous washing by a fluctuating water table during winter rains as did the pasture s o i l . In addition, the permeability of the 55. s o i l on the cultivated plot was lower. It i s therefore certain that the movement of water through t h i s s o i l was lower during the dormant season and the thoroughness of leaching probably not as complete as i n the pasture s o i l . These considerations, combined with the fact that the pro-perties of the two s o i l s are d i f f e r e n t , may account i n part at least for the d i f f e r i n g behaviour of the s o i l s with res-pect to sodium accumulation. The following values for exchangeable magnesium calculated as a percentage of the determined exchange capa-c i t y were observed from the analysis of the surface layer: o r i g i n a l Mg content 6.7%; after one season's i r r i g a t i o n 7.2%; and aft e r two season's i r r i g a t i o n 14.2%. Eor-. the 4-8" layer of s o i l , the corresponding values are 5.9%, 6.67» and 10.5%. The magnesium content d e f i n i t e l y increases with the i r r i g a -t i on treatments arid i t is possible that t h i s cation could continue to bu i l d up on the exchange material with further i r r i g a t i o n s . In t h i s event, Ca would probably suffer a further reduction (since these two ions are a l i k e i n re-placing power) with the resu l t that an acute deficiency of Ca for plant growth would be threatened. The position of potassium on the exchange complex i s apparently not much altered by the treatment. There does seem to be a small loss of t h i s ion following the f i r s t year's i r r i g a t i o n s ( o r i g i n a l potassium 2.9% of exchange capa-c i t y , after 1951 i r r i g a t i o n s 2.4%), but a si m i l a r reduction is not experienced during 1952-53. In preparing the land for 56. the corn crop of 1952, potassium f e r t i l i z e r was applied and th i s application i s r e f l e c t e d in the analysis. Any changes which did occur i n exchangeable K were of such small magni-tude as to be unimportant. Table VIII presents the i r r i g a t i o n and dormant-season leaching effects on the accumulation and d i s t r i b u t i o n of s a l t s i n the p r o f i l e of the cultivated p l o t . The e l e c t r i -c a l conductivity values anly are reported since they were observed to correlate well with the t o t a l salt status. TABLE VIII SALT STATUS OP THE CULTIVATED SOIL AS AFFECTED BY IRRIGATION 1951 1952 1953 )EPTH Original S o i l After . 1st I r r i g * Lfter 2nd i r r i g . After 3 r d I r r i g . After Winter Leaching After 3rd I r r i g . After Winter Leaching 0 - 4" .19 . 2.00 2.60 4 . 3 5 .15 • 2.60 .26 4 - 8 n .21 .68 .76 1.79 .16 2.41 .33 8-12" .18 .83 .67 .81 .37 2.47 1.00 L2-18" .20 • 46 .34 .58 .95 1.67 1.59 L8-24" .23 .41 .36 .75 1.47 1.68 1.67 NOTE — See Appendix for complete analysis. These values i l l u s t r a t e the s a l t - f r e e nature of the s o i l before i r r i g a t i o n s were begun, and depict c l e a r l y the progressive increase i n s a l i n i t y with each i r r i g a t i o n . It can also be seen from the data that complete removal of ac-cumulated s a l t s from the surface eight inches of s o i l oc-cur ed over the winter of 1951-52, most of the leached s a l t s 57. moving through the subsoil and passing out of the s o i l in the drainage. Reclamation was not as complete in the spring of 1953 as i t was the'previous spring, but a greater amount of sa l t was present i n the s o i l in the f a l l of 1952 than at the same period in 1951. In addition, the 1952-53 winter r a i n f a l l was less (21.7 M as compared to 26.4**) and the larger carry-over of salt s i s therefore to be expected. The p o s s i b i l i t y exists that the s a l t content of the s o i l in the spring w i l l become higher with each successive year's i r r i g a t i o n because of incomplete leaching of s a l t s during the dormant season. In this event, the point would eventually be reached where s o i l s a l i n i t y at planting time would be so great as to materially retard seed, germination and plant growth. In Table IX calculated osmotic pressure values are presented along with data on the moisture equivalent and w i l t i n g point (15 atmospheres) percentages for the s o i l at f i v e depths. The values represent the solution concentration i n i r r i g a t e d and control areas for samples taken following the t h i r d i r r i g a t i o n of 1951 (the year that the plot was planted to sugar-beets and peas). 58. TABLE IX CALCULATED OSMOTIC PRESSURE OE SOIL SOLUTION AT THE MOISTURE EQUIVALENT PERCENTAGE AND AT THE 15 ATMOSPHERE PERCENTAGE 15 ATMOSPHERE i # )smotic Pressure i n Atmospheres DEPTH M.E« % 3ontrol S o i l at I r r i g a t e d S o i l at «.B. P.W.P. M.E. P.W.P. 0- 4" 44.4 1 7 . 6 <1 1.2 16.0 >40 4- 8" 45 . 7 16.8 <1 1.4 5.9 1 3 . 5 8-12" 45.2 15.1 <1 1.2 2 . 6 6.0 12-18" 42.2 15.2 <1 1.5 1.9 4 . 5 18-24" 42.? 1 3 . 1 <1 1 . 7 2 . 5 6.0 ft Approximately the w i l t i n g p o i n t percentage With res p e c t t o the c o n t r o l p l o t s a l l of the water i n the s o i l above the i n d i c a t e d permanent w i l t i n g p o i n t would be a v a i l a b l e to the p l a n t . Osmotic s t r e s s e s i n the w i l t i n g range are very s m a l l at a l l depths, and p h y s i c a l t e n s i o n (pressure p o t e n t i a l ) f o r c e s t h e r e f o r e are much more important i n r e s t r i c t i n g water movement i n t o the plant than are osmotic f o r c e s i n t h i s s o i l . The extremely h i g h osmotic c o n c e n t r a t i o n i n the s o i l s o l u t i o n at 0-4" depth i n the i r r i g a t e d s o i l suggests t h a t the plant would not be able t o e x t r a c t water from t h i s l a y e r even at the moisture e q u i v a l e n t percentage. The d i f f e r e n c e i n osmotic g r a d i e n t between the pl a n t r o o t c e l l s and the e x t e r -n a l s o l u t i o n would be somewhat l a r g e r at depths g r e a t e r than 4", however, and pl a n t s would be o b l i g e d to meet t h e i r water requirements i n the main from deeper h o r i z o n s i n t h i s s o i l . 59. This means that the true permanent w i l t i n g point i n the i r r i g a t e d s o i l to a depth of 4M at the time that the sample was taken would be close to the determined moisture equivalent percentage and that for the deeper horizons, w i l t i n g would occur at moisture contents between the moisture equivalent and 15 atmosphere percentage. Obviously, then, the uptake of water by plants would be seriou s l y retarded or prevented i f t h i s s o i l was allowed to become dry during the growing season. It i s f e l t that in t h i s s o i l , as i n the pasture s o i l , the normal f i e l d moisture percentage would be considerably higher than that indicated by the moisture equivalent per-centage, and for the same reason. The water table remained within three to four feet of the surface during the summer and i t would be expected that the s o i l ' s moisture content would be higher under these circumstances. Moisture samples taken at an appropriate time a f t e r a soaking r a i n showed the following moisture contents for s o i l samples from the fi v e depths sta r t i n g at the surface; 59.?%, 55.2%, 70.0%, 68.07= and 69.07-. These values are appreciably higher than the corresponding moisture equivalent values. The solution concentration i n the s o i l at f i e l d capacity would thus be less than that determined for the moisture equivalent values, but the l a t t e r moisture constant i s probably more representa-t i v e of the average s o i l moisture conditions obtaining during the growing season. 60. The pH values of the cultivated s o i l at various depths and times are plotted in the graph of Figure IY. The samples were taken i n the spring of 1951, 1952 and 1953 as well as after each i r r i g a t i o n a pplication during the t r i a l years 1951 and 1952.' The s o i l reaction i s observed to be less a c i d i c in the surface than in the subsoil, a c i d i t y increasing with depth. The explanation of the cause of this s i t u a t i o n i s as offered in explanation of the same observed phenomenon i n the pasture s o i l . The pH l e v e l i n t h i s s o i l i s so low that i t i s pro-bable that a l i b e r a l application of lime would r e s u l t i n im-proved response for many crops. In spring, the pH of the s o i l i s generally higher than i n the f a l l , as might be expected. Of p a r t i c u l a r interest i s the fact that the f i n a l pH of the surface (0-4 n) s o i l after two year's irrigations' i s appreciably higher than i t was at the outset of the t r i a l . Thus, the o r i g i n a l pH was 4.83 and the f i n a l pH 5.78. A small and perhaps i n s i g n i f i c a n t increase was observed at the intermediate stage i n the spring of 1952 (pH 4.93)• Tbe pH increase i n the spring of 1952 and 1953 i s general and con-sistent i n the 4-8" and 8-12" layers also. When one considers that the exchangeable sodium percentage at 0-4" depth increased from 2.1% i n 1951, to 6.0% and to 14.1% i n the'years 1952 and 1953 respectively, and also that a similar increase (2.10% then 7.3% and f i n a l l y 17.2%) occurred in the 4-8" layer of s o i l , i t seems p l a u s i -ble that hydrolysis o f adsorbed sodium could account for the observed pH r i s e . Whatever the reason, i t i s f e l t that the treatment i s responsible for thi s increase in pH. Pore d i s t r i b u t i o n and t o t a l porosity determi-nation on the control and i r r i g a t e d areas of the cultivated s o i l are reported i n Table X, The values reported are averages for s o i l cores in t r i p l i c a t e unless otherwise noted, TABLE X PORE DISTRIBUTION IN THE CULTIVATED SOIL Treatment and % Porosity at . Tension of Total Porosity Volume Weight Horizon 0-20cm. 0-40cm. 0-60cm. Control S o i l Surface 19-7 22.7 24.1 66.8 .75 Irrigated S o i l Surface # 15.4 18.2 19.5 71.4 .75 Control S o i l Subsoil 14.0 16 .2 17.0 64.8 .92 Irrigated S o i l Subsoil # 13.1 15.9 17 .2 69.9 . .81 # Average for 2 cores only One core from each of the i r r i g a t e d surface and subsoil samples had to be omitted from the average because of the e r r a t i c behaviour of these cores during the subse-quent percolation rate determinations. E l e c t r i c a l conducti-v i t y values of the percolates also suggested that the cores were unr e l i a b l e . In the preceding tension data there does seem to be 6 3 . evidence of some s t r u c t u r a l d e t e r i o r a t i o n i n the s u r f a c e s o i l . The d i f f e r e n c e i s s m a l l , though, and i t i s pointed out t h a t on the i r r i g a t e d p l o t the b e a t i n g a c t i o n alone of the f a l l i n g spray from the s p r i n k l e r would l i k e l y cause some pu d d l i n g . The i r r i g a t e d area was maintained n e c e s s a r i l y at a higher moisture l e v e l , too, and the water s t a b i l i t y of the s o i l s t r u c t u r a l aggregates would a l s o be concerned. I t i s a p p r e c i a t e d t h a t these two f a c t s could e s i l y account f o r the s m a l l d i f f e r e n c e s observed. There i s no suggestion of s t r u c t u r a l d e t e r i o r a t i o n i n the t o t a l p o r o s i t y v a l u e s f o r the t r e a t e d and c o n t r o l s o i l s . The low volume weight f i g u r e s i n d i c a t e that the sub-s o i l i s more dense than the s u r f a c e s o i l , and r e f l e c t the high p o r o s i t y and organic matter v a l u e s of these s o i l s . Table XI presents the p e r c o l a t i o n r a t e observa-t i o n s f o r the f o r e g o i n g core samples. TABLE XI PERCOLATION RATES FOR SURFACE A N D SUBSOIL OF IRRIGATED PLOT Inches per Hour During 3 r d Hour 7 t h Hour 1 0 t h Hour Surface S o i l C o n t r o l 4 . 1 6 3 . 9 0 3 . 8 3 Surface S o i l I r r i g a t e d 1 . 2 5 1 . 1 7 1 . 3 3 S u b s o i l C o n t r o l 3-29 2 , 9 5 2 . 8 2 SUbsoil I r r i g a t e d 3 . 0 1 2 . 2 5 1 . 9 0 The p e r c o l a t i o n r a t e s of these cores do seem to i n d i c a t e some s t r u c t u r a l breakdown i n the s o i l from the 64. treatment area, both i n the s u r f a c e and i n the s u b s o i l . The r e d u c t i o n i n r a t e while a p p r e c i a b l e , i s ' n o t s e r i o u s s i n c e the t r e a t e d s o i l s t i l l has a s a t i s f a c t o r y p e r c o l a t i o n r a t e . The d e t e r i o r a t i o n i n s t r u c t u r e as apparent i n Table 21 may seem incongruous when compared to the r e s u l t s of the t e n s i o n t a b l e measurements f o r the same c o r e s . The s a t u r a t e d s o i l core samples from the i r r i g a t e d area when placed on the t e n s i o n t a b l e were s t i l l charged with s a l t . T h i s s a l t would tend to prevent the s o i l c o l l o i d s from d i s p e r s i n g and thus s t r u c t u r a l breakdown would not be d i s c e r n i b l e . During'the subsequent p e r c o l a t i o n r a t e determinations on these co r e s , the s o l u b l e s a l t s were completely leached out ( t h i s was i n d i S cated by e l e c t r i c a l c o n d u c t i v i t y measurements), and t h e i r r e p r e s s i o n e f f e c t on d i s p e r s i o n was e l i m i n a t e d . The high sodium percentages i n the s o i l . w o u l d then cause the unstable s o i l aggregates to become d i s p e r s e d causing plugging of s o i l pores and consequently reducing the p e r c o l a t i o n r a t e . P l a n t S t u d i e s i Sugar Beets, Peas and Corn Sugar beets (var. Sharpe's Kleinwanzleben S) and f i e l d peas (var. Laxton Progress) were pl a n t e d on the " c u l -t i v a t e d p l o t " on May 2 8 t h , 1951. S p r i n k l e r i r r i g a t i o n s were a p p l i e d to the "treatment" block on the f o l l o w i n g dates: J u l y 1 2 t h , 2 7 t h , and August 7 t h , 1951, The c o n t r o l block was not i r r i g a t e d * . On the date of the f i r s t i r r i g a t i o n , the sugar beets were w e l l e s t a b l i s h e d and the peas had j u s t begun to 6 5 . form pods. Ten days after the f i r s t i r r i g a t i o n the foliage of the treated peas began to turn an abnormal brown color and the plants appeared to be dying, while the sugar beets showed no p a r t i c u l a r effects of the treatment. At t h i s time also extensive damage to the foliage of elderberry and silage corn which bordered the plot became noticeable, presumably as a result of spraying v/ith the saline water (see Plate I I ) . Poli a r damage to the peas became very pronounced after the second i r r i g a t i o n , although many of the pods remained green. The sugar beets, on the other hand, seemed to thrive under the treatment and were apparently more vigorous in the treated than in the control block. At the time of the t h i r d i r r i g a t i o n , the peas in the treated block had a l l died \vhile only about half the pea plants in the control block had reached maturity and were dying down. Three weeks after the t h i r d i r r i g a t i o n , the leaves of the sugar beets began to exhibit considerable margi-nal burning — ir r e g u l a r necrotic areas -- but an the whole the plants were s t i l l apparently superior to the control plants. Harvesting of the peas was delayed u n t i l a l l growth had ceased. The i r r i g a t e d peas, having matured (or died) e a r l i e r , were harvested on August 9th, the control peas on August 24th. Y i e l d of dry peas was obtained for each row of the twelve rows i n each treatment, but i t . i s f e l t that the values are of questionable significance because of crop losses due to an infestation of pheasants. 66. Beet top and root y i e l d s were a l s o recorded at the harvest which took place on October I J t h , 1951. Here again i t i s b e l i e v e d t h a t the y i e l d s are u n r e l i a b l e because of the d e f o l i a t i o n caused by pheasants. The y i e l d s , however, are recorded i n the f o l l o w i n g t a b l e : TABLE 211 SUGAR BEET AND PEA YIELDS AS AFFECTED BY IRRIGATION WITH SALINE WATER CROP YIELD C o n t r o l I r r i g a t e d p r i e d Pea Seed £ 176.8 159.4 Sugar Beet Tops # 15.46 22.00 Sugar Beet Roots §• 10.15 10.00 H Y i e l d i n gms. per 48 f e e t of row -- average f o r 12 rows. # Y i e l d i n l b s . per 25 f e e t of row — average f o r 12 rows. Because of the unfortunate circumstances which cast doubt on the v a l i d i t y of the above y i e l d f i g u r e s , i t i s per-haps not p o s s i b l e to draw d e f i n i t e c o n c l u s i o n s from t h i s data r e g a r d i n g e f f e c t s of the treatment on y i e l d . I t i s , however, the o p i n i o n of the author that the y i e l d of peas was a c t u a l l y reduced by the treatment, and th a t the beet ro o t y i e l d was not much a f f e c t e d under the same treatment. T e s t s of cooking q u a l i t y r e v e a l e d t h a t the d r i e d peas from the i r r i g a t e d b l o ck r e q u i r e d a longer cooking p e r i o d to reach a c e r t a i n stage of tenderness than d i d peas from the c o n t r o l b l o c k . The top:root r a t i o f o r the c o n t r o l and i r r i g a t e d 6 7 . sugar beets was calculated and was found to average 1 . 5 : 1 and 2 . 2 : 1 respectively. These figures are of si g n i f i c a n c e , for i t was found that the tops-root r a t i o for each of the twelve rows under a pa r t i c u l a r treatment showled l i t t l e v a r i a t i o n from the reported average. The cause of the higher r a t i o observed with the i r r i g a t e d sugar beets i s not clear -- i t could be due to the more p l e n t i f u l water supply, to the s a l t s earried to the s o i l i n i r r i g a t i o n water, to decreased aeration, or even to improvement in nitrogen assimilation i n the i r r i g a t e d s o i l . Differences in succulence between the i r r i g a t e d and control (non-irrigated) beet leaves (90% and 89% water respectively) were very small and perhaps i n s i g n i f i c a n t and certainly do not account for the large differences in top:root r a t i o found. Eaton ( 1 7 ) and Dorph-Petersen and Steenbjerg ( 1 3 ) also observed no effect of s a l t s on the succulence of sugar beets, although other investigators ( 8 , 5 3 , 6 5 ) report either decreased or increased dry matter content with s a l t a p p l i c a -tions depending presumably on conditions of moisture tension. It would seem that the treatment had a stimulating effect on the growth of the beet tops, at least, and t h i s feature could be of p r a c t i c a l a g r i c u l t u r a l importance where such crops were being grown for greens or for cattle fodder. The quality of the sugar beet roots was rather seriously lowered by the treatment as evidenced by the following analysis secured through the courtesy of the B. C. Sugar Refining Co. Ltd. 68. SUGAR BEET QUALITY Treatment Percentage Sugar Percentage Purity Irrigated 12.5 8 0 . 4 Control 15.5 8?.0 In this connection, Harmer and Benne (21) observed a similar decrease in sugar content and purity of beets when NaCl was applied to a s o i l containing inadequate potassium for the needs of the crop. During the year 1952, a crop of silage corn was grown on the plot which had the previous year been sown to sugar beets and peas. Saline water was applied by sprinkler to this corn f i e l d . Following the f i r s t application of water, the i r -rigated corn was observed to be suffering extensive foliar:-damage (tip and marginal burning). The damage became in-creasingly pronounced with the second and third irrigation, and the plants were consequently sparse and stunted. At harvest time, the irrigated corn crop was so poor that i t was considered valueless, whereas a satisfactory crop was obtained from the control (non-irrigated) area. Although no f i e l d studies were conducted in the summer of 1953, observations were made on the plot referred to above which supported a mixed sunflower and silage corn crop during this year. Plate III shows that the silage crop (which received no irrigation) was badly stunted on that portion of the plot which had been irrigated the two preceding years. 69. That the crop-producing power of the s o i l had been impaired by i r r i g a t i o n with saline water i s thus well i l l u s t r a t e d . From the foregoing data and observations, i t i s concluded that the i r r i g a t i o n treatment was harmful to the growth of corn, to the y i e l d and cooking q u a l i t y of the peas, and of doubtful value as regards y i e l d of sugar beets but harmful to th e i r quality, i i Pasture Grasses Although the pasture had o r i g i n a l l y been seeded to red clover and timothy, the sod at the outset of the i r r i g a -t i o n t r i a l s in?1950 was observed to be composed i n addition of the following species: Yorkshire fog, red top, plantain, slender wheat grass and perennial rye grass. A t o t a l of ceightt, acre inches of water, in three equal applications, was applied annually to the plot during the years 1 9 5 0 , 1 9 5 1 and 1 9 5 2 . Within a few days of the second i r r i g a t i o n of 1 9 5 0 the following observations were made on the pasture: on that part of the pasture subjected to i r r i g a t i o n the grass mixture was verdant; on the control area the grass was uniformly brown and droughty; but between the two areas, i n the t r a n s i t i o n zone, a belt of dark brown grass was manifest. The same dark t r a n s i t i o n zone was also v i s i b l e during the i r r i g a t i o n t r i a l s of 1 9 5 1 and 1 9 5 2 . This darker zone, i t was thoerized, was caused by an excessive accumulation of s a l t s on the f o l i a g e with attendant plasmolysis and other effects on the plant t i s s u e . The spray pattern of an i r r i g a t i o n sprinkler is such that an accumulation of s a l t J 70. from a saline i r r i g a t i o n water could occur on the foliage because of the intermittent and sparse f a l l of water at the extreme l i m i t of the s p r i n k l e r 1 s .arc, and the opportunity for evaporation to dry the foliage before the next increment of s a l t arrived i n a water droplet. No such accumulation would be possible on the grass nearer the sprinkler head, since here the foliage i s continually washed by the f a l l i n g spray. The i r r i g a t e d plot was observed to produce much more hay than the control plot during the three years of the t r i a l and no change in the species composition as a re s u l t of the i r r i g a t i o n was di s c e r n i b l e . Cattle were allowed to graze at w i l l in the pasture and i t was noticed that they preferred to crop the grass on the i r r i g a t e d area, attesting perhaps to the p a l a t a b i l i t y of the treated grass. The animals were pro-vided with s a l t l i c k s elsewhere in the pasture and so pre-sumably did not require the salt which would be present on the foliage of the i r r i g a t e d p l o t . Because of the presence of the grazing animals, y i e l d data for the f i r s t two years were unobtainable. Wire cages were placed i n the pasture during the year 1952, and yiel d s taken. The pasture grass y i e l d s reported in Table XIII were obtained from cuttings of plots 9 feet square in area (2 for each treatment) enclosed by the wire cages. One cutting was made on October 17th, 1952. 71. TABLE XIII GRASS YIELDS AS AFFECTED BY IRRIGATION WITH SALINE WATER TREATMENT Fresh wt. of Harvest in gms./9 s q . f t . YIELD AVERAGE YIELD Plot 3ontrol Plot 1 2 26.3 113.2 69.8 Plot Irrigated Plot 3 4 734.4 455.8 605.I These figures serve to emphasize the wide v a r i a -tions in s o i l f e r t i l i t y on the pasture plot and also demon-strate convincingly the need for i r r i g a t i o n . It i s re-markable that the yie l d was so much improved under i r r i g a -t i o n i n view of the very poor quality of the water applied Plant Analysis Analyses of the plant tissues were made for the constituents Ca, Mg, K and Na to determine the effects of the treatment on the plant composition and uptake of other elements. Figure V presents graphically the results of these analyses. In connection with t h i s graph, i t i s pointed out that a l l values are reported i n terms of milligrams per hundred grams of dry matter, and further, that the pea seed analyses for the control and i r r i g a t e d p l o t s , though reported in the same terms, are not d i r e c t l y comparable since the size of peas was greatly affected by the treatment. Thus 10 g. of i r r i g a t e d peas contained 47 peas, while the same weight of control peas contained only 34 seeds. This would c e r t a i n l y 7 3 . affect the mineral content on a weight basis. The cuttings from each of the four cages were chemically analyzed separately. It w i l l be noted that the quantity of grass obtained from plot one was very small be-cause of the sparse growth and consequently the analysis was d i f f i c u l t and perhaps subject to error. An examination of the graph reveals that the mineral content and the sodium content of the tissues was markedly i n -creased by i r r i g a t i o n with the high Na-Mg water, except in the case of the pasture grasses. The calcium content of sugar beet roots and leaves was lowered by the treatment as was the calcium content of the grasses. Beet roots showed an increase i n Mg, K, and Na as a resu l t of the treatment, while the leaves accumulated less Mg and K, but very large amounts of Na under these conditions. The potassium content of the peas was lowered and the sodium content much increased by i r r i g a t i o n . Because of the unfortunate size difference between the i r r i g a t e d and control peas, the effect of the treatment on Ca and Mg ab-sorption by thi s species is not clear. Apparently the pasture grasses were able to ex-clude Na applied in the i r r i g a t i o n water, but i t w i l l be apparent from the s o i l analysis data that the pasture s o i l was well supplied with t h i s element prior to the treatment. In general, about a l l that can be said regarding the 74. changes in plant composition a r i s i n g from i r r i g a t i o n with saline water is that the mineral content and Na content of the crops i s increased, except for the pasture grasses, and the content, of Ca decreased i n the crops analysed. From the data i t seems that an i n s u f f i c i e n c y of Ca for plant growth may he occasioned by i r r i g a t i o n with such a water, more part i c u -l a r l y because these s o i l s are already low in.calcium. The pea seed v i a b i l i t y tests were undertaken to determine whether the saline i r r i g a t i o n water tr.eatment had conferred any advantage on the i r r i g a t e d peas with respect to t h e i r a b i l i t y to germinate in a saline environment and to i n -dicate whether death of the pea plants on the i r r i g a t e d plot had occurred before the seed had come to maturity. The re-sults of the tests were as presented in Table XIV. TABLE XIV VIABILITY OF CONTROL AND IRRIGATED PEAS Percentage Germination Elapsed Treatment time Control Peas Irrigated Peas (days) Germinated 2 8 4 i n 4 72 68 D i s t i l l e d 6 92 76 later 8 92 82 Germinat ed 2 4 2 in Saline 4 4.6 50 Solution of 6 94 84 2 1/2 Atmos. 8 ?8 84 Concentration Germinated 2 4 2 i n Saline 4 56 56 Solution of 6 100 76 5 Atmos. 8 100 76 Concentration 7 5 . I t i s seen that germination was delayed i n the stronger s a l t s o l u t i o n s as found by Shive ( 5 7) and by R u d o l f s ( 5 2 ) , and t h a t germination was not prevented by the s a l t c o n c e n t r a t i o n employed. The v i a b i l i t y of the seed from the i r r i g a t e d p l o t i s a p p r e c i a b l y lower, suggesting that the complete maturation of a l l seeds formed was prevented by the e a r l y death of the p l a n t s . SUMMARY AND CONCLUSIONS 1 . A f i e l d study of the e f f e c t s of s a l i n e water on the p h y s i c a l and chemical p r o p e r t i e s of s o i l s and on the growth and m i n e r a l composition of p l a n t s grown thereon has been conducted. Annual a p p l i c a t i o n s t o t a l l i n g eight acre inches of water were made f o r two to t h r e e years to E r a s e r R i v e r D e l t a s o i l s s u p p o r t i n g pasture g r a s s e s , peas, sugar beets, and corn. 2 . I r r i g a t i o n water c o n t a i n i n g more than 1 3 , 0 0 0 pip.m. d i s s o l v e d s a l t s caused a marked accumulation of s a l t s i n the s u r f a c e s o i l of pasture and c u l t i v a t e d f i e l d s , r e s u l t i n g i n h i g h osmotic p r e s s u r e s i n the s o i l s o l u t i o n . 3 . The l e a c h i n g w i n t e r r a i n s removed a l a r g e p o r t i o n of the s a l t accumulations, but enough s a l t remained i n the s o i l i n the s p r i n g f o l l o w i n g two s u c c e s s i v e year's i r r i g a -t i o n s to r e t a r d the growth of a n o n - i r r i g a t e d s i l a g e crop. 4. The exchangeable sodium percentage i n the c u l t i v a t e d s o i l was g r e a t l y i n c r e a s e d by the i r r i g a t i o n treatment ( o r i g i -n a l l y 2 . 1 % , f i n a l l y 14 . 1 % ) , and the magnesium percentage a l s o i n c r e a s e d . The evidence suggests that, under continued i r r i -76. gation, these ions may reach an excessive l e v e l in the s o i l and occasion st r u c t u r a l decay and disturbance of the metabo-lism of plants. 5. The pasture s o i l , on the other hand, showed only small gains in exchangeable sodium and magnesium percentages before an apparent equilibrium between the s o i l and treatment was established. The thorough winter washing by a f l u c t u a -t i n g water table -- a situation peculiar to t h i s s o i l -- i s believed to account for i t s di f f e r e n t behaviour with respect to sodium and magnesium accumulation. 6. The treatment seriously reduced, i n both s o i l s , the already low amount of available calcium. Plant calcium defici e n c i e s are thus threatened when s o i l s are i r r i g a t e d v/ith strongly saline waters. The systematic application of lime under these circumstances i s to be recommended, both to ensure s u f f i c i e n t calcium for plant needs and to discourage the tendency for undesirable ions to accumulate on the ex-change material. 7. The potassium content of the s o i l s was very l i t t l e affected by the treatment and l i t t l e consideration need be given t h i s aspect of the problem. 8. The s o i l reaction on the pasture plot was unaltered by the treatment, but an increase i n pH was observed on the cultivated s o i l . In explanation i t i s f e l t that the appre-ciably higher sodium percentage in the cultivated s o i l , as already indicated, was responsible for the observed pH r i s e . 77« 9. Pore d i s t r i b u t i o n and percolation rate determina-tions revealed no serious alterations i n s o i l structure which could be d e f i n i t e l y ascribed to the treatment. The high organic matter content of the s o i l s selected for the study would, however, m i l i t a t e against s t r u c t u r a l breakdown. 1 0 . Pea and silage corn y i e l d s were depressed, sugar beet y i e l d unaffected, and pasture grass yields increased e i g h t - f o l d by the i r r i g a t i o n treatments. The quality of a l l crops was impaired. It i s believed that much of the observed plant injury was occasioned by excessive accumulation of s a l t s on the f o l i a g e . 1 1 . Plant analysis data indicated that, with the ex-ception of the grasses, the sodium content of the samples analysed was much increased by the treatment. The ti s s u e s , generally, showed a decreased uptake of calcium. 1 2 . The author is of the opinion that the usual stan-dards regarding permissible concentration of s a l t s in i r r i -gation waters do not apply i n the Fraser River Delta region with i t s peculiar climate. Waters containing upwards of 3000 p.p.m. salt could doubtless be used to advantage without p a r t i c u l a r hazard to s o i l s or crops, providing that the s o i l status of calcium and organic matter i s maintained by good farming practices. It i s recommended that, where strongly saline waters are used f o r i r r i g a t i o n , the s o i l should be analysed p e r i o d i c a l l y for t o t a l s a l t s , and sodium p a r t i c u l a r l y to detect undesirable changes. 78. •Plate I Cultivated f i e l d , showing control plot of sugar beets and. peas in foreground, i r r i g a t e d plot right background. Plate II Danage to corn and elderberry occasioned by accumulation of salt on f o l i a g e . •Plate III Stunted silage crop of corn and sunflowers on portion of cultivated f i e l d which had been i r -rigated for two years. Normal crop in background. I APPENDIX CHEMICAL ANALYSIS OP SOIL SAMPLES" FROM PASTURE PLOT (in mgs./lOO g.soil) 1 9 5 0 1 9 5 1 1 9 5 2 1 9 5 3 CATIONS DEPTH ORIGINAL" SOIL AFTER 1ST IRRIG. AFTER 2ND IRRIG. AFTER 5RD IRRIG. AFTER WINTER RAINS AFTER 1ST IRRIG. AFTER , 2ND IRRIG. AFTER 5RD IRSIG. AFTER WINTER RAINS AFTER 1ST IRRIG. AFTER 2ND IRRIG. AFTER 3RD IRRIG. AFTER WINTER RAINS Sodium 0- 4" 4- 8" 8-12" 1 2 - 1 8 " 18-24? 45.4? 40 .28 8 5 . 5 7 1 6 9 . 8 5 400 .75 45.49 50.81 1 2 5 . 2 8 119.14 -167.83 95.69 55.91 114.54 74.88 211 .82 258.22 277 .91 490.20 555.40 297.54 72.09 7 5 . 5 1 84 .91 6 9 . 1 7 101.40 1 2 8 . 5 8 89 .69 67 .70 86.92 251.22 2 7 5 . 7 0 225.64 224.21 141 .95 3 8 8 . 9 6 194 .58 229 .56 2 5 0 . 6 1 254.09 106.52 8 2 . 5 0 124.12 95.40 472 .59 189.75 127 . 7 0 157.70 124 .28 205.57 216 .81 1 8 5 . 3 8 359*25 282.22 415.05 2 5 5 . 0 9 308.88 2 8 9 . 3 8 2 8 3 . 8 2 315.25 8 0 . 1 5 79.42 97.47 99.7.0 524 .28 Potassium 0-4" 4- 8" 8-12" 12 -18 ' ! 18-24" 11.97 9.94 15.22 2 6 . 1 9 27 .72 14.10 15.56 22 .78 2 3 . 5 1 27 .20 8 . 9 1 8.10 21.02 20.54 28.12 26.59 55.44 42 .18 5 6 . 1 4 2 5 . 0 6 16.15 1 5 . 6 8 20.45 22.55 24 .70 10.88 10 .66 12.01 1 7 . 2 5 26.02 14 .50 17.46 16.64 25.12 27.47 22 .59 22 .85 22 .66 25.92 15.45 17.76 25 .51 25.99 5 2 . 2 5 11.00 15.57 20.52 21.58 28 .75 22 .51 22 .55 2 6 . 5 5 2 9 . 3 2 3 5 . 4 9 25 .80 25.25 2 7 . 0 5 2 9 . 8 1 5 1 . 5 4 10 . 72 1 0 . 8 8 18 . 25 22 .71 54.98 Calcium 0- 4" 4- 8" 8-12" 12 -18 ' ! 18-24" ' 555.49 500.01 IIO .67 2 2 1 . 5 9 146.27 1 1 4 . 9 0 5 5 3 . 9 0 2 3 4 . 1 2 125.42 2 5 3 . 0 6 178.7 2 101 .57 1 5 1 . 4 5 158.11 62.94 ' 2 6 0 . 9 5 260.46 97.09 Magnesium 0- 4" 4- 8 " 8-12" 12-18" 18-24" 56.75 55 .62 55 .65 6 7 . 0 7 6 4 . 9 2 8 5 . 6 4 75.61 60.66 43 . 05 71.10 4 8 . 1 5 61.46 74.54 65.10 55. 79 67.01 58.99 59 .22 EXPERIMENTAL DETERMINATIONS EOR PASTURE PLOT SOILS 1 9 5 0 1951 1952 1953 DEPTH ORIGINAL SOIL . AFTER 1ST IRRIG. AFTER 2ND IRRIG. AFTER 3RD IRRIG., AFTER ' WINTER' RAINS ; AFTER : 1ST IRRIG. AFTER 2ND IRRIG. AFTER 3RD IRRIG. A.FTER WINTER RAINS LFTER 1ST [RRIG. AFTER 2ND IRRIG. AFTER 3RD IRRIG. AFTER • WINTER RAINS PH - 0 - 4" 4 - 8 " 8 - 1 2"8 1 2 - 1 8 " 18-24" 5 . 1 6 4 . 2 9 5 . 8 6 3 . 5 7 3 . 4 3 4.37 4 . 2 2 3 . 6 3 3.67 3 . 6 1 5.04 5 . 0 3 3 . 7 5 3 . 7 1 3 . 6 3 4 . 0 8 4 . 0 0 3 . 6 8 3 . 6 9 3 . 4 7 4 . 7 7 4 . 4 9 3 . 7 1 3 . 7 7 3 . 6 3 4 . 4 5 3...97 3.82 3 . 6 8 . 3 . 5 4 4 . 5 5 4 . 4 7 3 . 5 5 3 . 6 0 3 . 4 8 5 . 0 2 4 . 24 3 . 6 3 3*60 4 . 9 3 4 . 4 3 3 . 8 3 3.77 3 . 5 9 5 . 4 5 4 . 5 5 3.71 3 . 7 3 3 . 6 7 4 . 2 8 4 . 2 8 3 . 6 3 3.70 3 . 6 4 4 . 1 7 3 . 9 8 3 . 6 6 3 . 6 3 3 . 6 3 4 . 9 7 4 . 7 5 3 . 9 5 3 . 9 0 3 . 7 4 E l e c t r i c a l Conduct i v i t y . 0 - 4" 4- 8 " 8 - 1 2 " 1 2 - 1 8 " 18-24" . 3 6 .54 . 8 8 1 .73 3 . 8 5 . 5 3 . 4 6 1 . 2 0 1.19 1.73 1 . 1 8 . 4 3 . 8 8 . 8 2 2.50 2.40 1 . 8 1 3 . 6 0 3 . 0 9 3 . 0 0 . 3 7 .40 . 6 5 . 6 9 1.12 • I . 1 3 ,• . 6 9 '•• . 6 1 •ii*'*8.8 1^2 0% 2 2.16 1 . 3 5 2.42 1 . 4 8 3 . 7 0 . 8 6 1 . 5 3 1 . 9 4 2 . 0 0 . 3 6 . 3 8 . 9 4 1 . 0 2 5 . 0 0 . 9 8 .59 1 . 0 9 1 .28 2 . 0 7 1 . 4 7 1 . 3 6 2.72 2 .63 3 . 8 0 1 . 8 4 2 . 0 5 2 . 7 4 2 . 7 7 3 . 0 5 . 2 3 .25 . 5 3 . 8 0 2 . 8 0 Exchangeable lydrogen . 0 - 4" 4 - 8 " 8 - 1 2 " 1 2 - 1 8 " 18-24" 3©o78 4 6 . 1 7 4 6 . 9 5 6 1 . 7 5 3 8 . 4 4 4 7 . 8 I Sxchange 3 a p a c i t y 0 - 4" 4 - 8'! 8 - 1 2 " 1 2 - 1 8 " 18-24" 7 0 . 1 8 7 0 . 4 7 74.04 63.-14 7 7 . 1 0 105.92 .: '' ': V £7 . 5 0 •7-5.38 7 6-.7 3 68 .45 6 4 . 5 6 9 1 . 5 0 6 6 . 8 9 8 5 . 7 4 42 . 8 8 68.91 7 3.11-6 2 . 5 9 CHEMICAL ANALYSIS OF SOIL SAMPLES FROM CULTIVATED PLOT ( i n mgs/lOO g. s o i l ) 1 9 5 1 1952 1 9 5 3 3ATIONS DEPTH ORIGINAL SOIL AFTER 1ST IRRIG. AFTER 2ND IRRIG. AFTER 3RD IRRIG. AJ'TER ir/INTER RAINS. AFTER 1ST IRRIG. AFTER 2ND IRRIG. AFTER 3RD IRRIG. AFTER WINTER RAINS Sodium 0 - 4" 4 - 8" 8-12" 12 - 1 8 " 18-24" 2 0 . 7 8 18 . 6 9 1 1 . 3 1 10.29 1 2 . 3 6 2 1 9 . 6 9 44. 02 4 7 . 9 5 21 . 7 5 18 . 3 2 2 6 5 . 7 3 50.42 3 7 . 2 6 1 3 . 9 9 18 . 2 9 3 4 3 . 7 4 140 . 6 9 61 . 6 6 3 8 . 1 8 5 7 . 7 9 48.43 5 3 . 3 5 54 . 9 5 8 1 . 7 3 108.29 169 . 7 8 137 . 8 0 1 0 8 . 3 6 7 6.54 77 . 9 6 2 6 6 . 5 9 222 .07 1 6 1 . 3 6 111 . 9 7 124.02 331.00 342 . 7 0 239 . 7 2 149.06 145.34 126.02 148 . 77 1 7 0 . 3 0 183.44 132.61 Potassium 0 - 4" 4 - 8*' 8-12'! 12-18'! 18-24'! 4 8 . 9 2 3 7 . 9 1 2 6 . 0 4 2 6 . 1 4 2 5 . 6 4 54 . 5 9 40 . 3 5 34 . 5 8 31.44 27 . 0 9 46 . 8 2 37 .22 29 . 1 6 27 . 0 6 3 0 . 5 5 45 . 0 6 34 . 8 5 2 7 . 3 5 25.03 22 . 7 0 3 2 . 8 9 2 8 . 7 5 24 . 7 7 2 6 . 4 7 28.42 55.02 34.84 28.12 25.34 25.12 5 3 . 8 0 5 0 . 8 8 32.12 27 .6.1 29 .12 5 3 . 3 5 50.44 34 . 3 2 27 . 6 3 27 . 8 2 5 8 . 9 5 49 . 8 5 45 .06 34.70 2 8 . 6 2 Calcium 0 - 4 " 4 - 8V 8-12'! 12-18" 18-24" 243*26 2 0 0 . 8 0 40.61 2 6 . 8 1 1 8 . 8 6 2 1 3 . 8 6 145.72 8 1 . 6 3 38.00 ' 24.41 2 8 2 . 7 4 2 5 7 . 7 1 6 8 . 3 1 33.41 2 7 . 3 3 1 4 0 . 2 6 1 1 9 . 2 9 4 5 . 8 1 3 7 . 3 3 3 2 . 3 5 141.04 1 3 3 . 7 3 91 . 9 7 5 2 . 8 7 140.50 1 4 8 . 9 7 9 9 . 2 3 Magnesium 0- 4 " 4- 8 " 8-12"! 12 - 1 8 " 18-24" 35.20 29 .22 10 . 5 9 10.11 8.43 50.08 2 6 . 3 5 25 . 6 2 15 . 8 9 11.49 72 . 8 3 4 6 . 6 5 23 . 6 3 18.41 1 8 . 7 1 3 0 . 8 6 2 5 . 4 6 14.02 13 . 7 4 14 . 8 9 6 7 . 8 7 59.40 '38 .23 2 3 . 9 5 67 .22 4 7 . 7 8 39.11 EXPERIMENTAL DETERMINATIONS ON CULTIVATED PLOT SOILS CATIONS DEPTH 1951 195 2 1953 ORIGINAL SOIL AFTER 1ST IRRIG. A F T E R 2ND IRRIG. A F T E R 3RD IRRIG. A F T E R WINTER RAINS A F T E R 1ST IRRIG, A F T E R 2ND IRRIG. A F T E R 3RD IRRIG. AFTER"™ WINTER RAINS pH 0 -4 4 -8 8-12 12-18 18-24 4 .8J 4.54 4.05 3.97 3.17 4.47 4.06 3.66 3.68 3.66 4.47 4.44 3.68 3.77 3.73 4.31 4,38 3.87 3.74 3.67 4.95 4.87 4.22 3.73 3.42 4.72 4.64 3.98 3.63 3.46 4.64 4.55 3.94 3.75 3.60 4.73 4.41 3.83 3.67 3.54 5.78 5.30 4.36 3.87 3.63 E l e c t r i c a l Conduc-t i v i t y 0- 4 4- 8 8-12 12-18 18-24 .19 .21 .18 .20 2.00 .68 .83 .46 .41 2.60 .76 .67 .34 .36 4.35 1.79 .81 .58 .75 .15 .16 .37 .95 1.47 I .38 .99 1.14 1.07 1.34 2.52 1.95 1.55 1.42 1.37 2.60 2.41 2,47 I .67 1.68 .26 .33 1.00 1.59 I.67 Exchange-able Hydrogen 0- 4 4- 8 8-12-12-18 18-24 22.60 23.68 19.99 22,41 17.52 20.66 Exchange Capacity 0- 4 4- 8 8-12 12-18 18-24 43.22 40.97 21.87 22.05 22.58 43.55 41.47 41.54 26.58 22.97 40.01 40.74 25.26 20.85 22.03 35.37 31.83 24.04 21.38 21,44 38.00 38.37 24.51 20.66 38.89 37.49 36.31 79 BIBLIOGRAPHY 1 . AYERS, A.D., WADLEIGH, C.H., and MAGISTAD, O.O., "The i n t e r r e l a t i o n s h i p s of s a l t con-c e n t r a t i o n and s o i l moisture content xvith the growth of beans. Jour. Am. Soc. Agron. 3 5 : 7 9 6 - 8 1 0 , 1943 RICHARDSON, D., BERRY, J.W., and HOOD, R.L., Flame Photometry A Rapid A n a l y t i c a l Procedure, Ind. Eng. Chem. A n a l . Ed. 1 7 : 6 0 5 - 1 1 , 1 9 4 5 ed. Ocean waters. C o l l i e r ' s E n c y c l o p e d i a . 1 5 : 101-104, 1951 S o i l P h y s i c s . John Wiley and Sons, Inc., New York, 1940 ed., Sodium symposium. S o i l S c i . 7 6 : 1 - 9 6 , 1 9 5 3 The i n f l u e n c e of s a l t i n the s o i l on y i e l d of a g r i c u l t u r a l c r o p s . I n t . Cong. S o i l S c i . Trans. 1 : 411 - 1 3 , 1 9 5 0 7 . BOWER, C.A., REITEMEIER, R.G., and FIREMAN, M., Ex-changeable c a t i o n a n a l y s i s of s a l i n e and a l k a l i s o i l s . S o i l S c i , 7 3 : 2 5 1 - 6 1 , , 1 9 5 2 8 . BUTKEVICH, V.S., and MARUASHVILI, L.TT. , Plant uptake of potassium and y i e l d as induced by sodium c h l o r i d e , C.R. Acad. S c i . U.R.S.S. 2 2 : 1 2 7 - 3 0 , 19 3 9 , as c i t e d i n Chem. A b s t r . 3 3 : 6 5 0 7 , 1939 9 . CAMPBELL, R.B., and RICHARDS, L.A., Some moisture and s a l i n i t y r e l a t i o n s h i p s i n peat s o i l s . Jour.Am. Soc. Agron. 42: 5 8 2 - 8 7 , 1 9 5 0 1 0 . DEC0UX, L., VANDERWAEREN, J . , and SIMON, M., A c t i o n of i n c r e a s i n g a d d i t i o n s of sodium as sodium c h l o r i d e and sodium carbonate on development of the sugar beet. Pub, i n s t . beige, a m e l i o r a t i o n b e t t e r a v e . 9 : 2 7 1 - 9 , as c i t e d i n Chem. A b s t r . 37 : 3 2 1 6 , 1 9 4 3 2. BARNES, R.D., 3 . BARRY, C.P., 4 . BAVER, L.D., 5 . BEAR, F.E., 6 . BERG, C.V.D., 80. 11. DELEMENCHUK, M.I., and M 0 R 0 Z 0 V , A. S., Sodium chloride as a f e r t i l i z e r f or sugar beets. Tekh-niohni K e e l ' t u r i . 10: 50-3, 1939, as cited in Chem. Abstr. 36: 4263, 1942 12. DELOFFRE, G., Decline of structure of the s o i l s flooded by salt water i n 1944 i n the region of Dunkerque. Int. Cong. S o i l . S c i . Trans• 1: 413-15, 1950 13. DORPH-PETERSEN, K. , and STEENBJERG, F., Investigations of the eff e c t of f e r t i l i z e r s containing sodium. Plant and S o i l I I . No. 3: 283-300, 1950, 14.. DORSMAN,.; C., and WATTEL, M. , The inundations of 1944-1945 and th e i r effect on agri c u l t u r e . VII Salt damage to h o r t i c u l t u r a l crops. V e r s l . Candbouwk. Anderz. 57 .8: pp 55, 1951, as cited i n Hort. Abstr. 22:p.475« 15. DOUGHTY, J. L., The advantages of a s o i l paste for routine pH determination. S c i . Agr. 22: 135-38, 1942 16. DUNKLE, E. C., and MERKLE, F. G., The conductivity of s o i l extracts i n r e l a t i o n to germination and growth of certain plants. Proc. S o i l S c i . Soc. Am. 8: 185-88, 1943 17. EATON, F. M., T o x i c i t y and accumulation of chloride and sulphate s a l t s in plants. Jour. Agric. Res. 64: 357-99, 1942 18. FIREMAN, MILTON, Permeability measurements on disturbed s o i l samples. . S o i l Sc. 58: 337-53, 1944 19. FREAR, D. E. H. ed.., A g r i c u l t u r a l Chemistry. V o l . I. D. Van Nostrand Company Inc., New York, 1950. , , 20. GAUCH, H. G., and MAGISTAD, Q.C., Growth of strawberry clover v a r i e t i e s and of a l f a l f a and ladino clover as.affected by s a l t . Jour. Am. Soc. Agron. 351 871-80, 1943 21. HARMER, P.M., and BENNE, E. J., Eff e c t s of applying common salt to a muck s o i l on the y i e l d , composi-ti o n , and quality of certain vegetable crops and on the composition of the s o i l producing them. Jour. Am. Soc. Agron. 33: 952-79, 1941 81 22. , , Sodium as a crop nutrient. S o i l S c i . 60: 137-48, 1943 23. HARRIS, F. S., S o i l A l k a l i . John Wiley and Sons, Inc., Ne\T York and London, 19 20 24. HARRIS, J. A., GORTNER, JR. A.,, HOFFMAN, W. F. ,. LAWRENCE, J. V.,. and VALENTINE, A. T., The osmotic . . concentration, s p e c i f i c e l e c t r i c a l con-d u c t i v i t y , and chloride content of the tissue f l u i d s of the indicator plants of Tooele Valley, Utah. Jour. Agric. Res.. 27: 893-924, 1?24 23„. HARTWELL, B. C., and PEMBER, F. R. , Sodium as a p a r t i a l substitute for potassium. R. I. Agr.. Exp. Sta. 21st Ann. Rpt. Part I I : 243-.S5, 1908 . , , : 26. HAYWARD, H. E., and LONG, E. M., Some effects of sodium s a l t s on the growth of the tomato. Plant Physiol. 18: 536-69, 194.3 27. HISSINK, D. J., The reclamation of the Dutch saline s o i l s (solonchak) and t h e i r further weathering under the humid climatic con-ditions of Holland. S o i l S c i . 45: 83-94.,, 193.8 . . . 28. HOLT, M.E., and VOLK, N. J., Sodium as a plant nutrient and substitute for potassium. Jour. Am. Soc. Agron. 37:, 821-27 , 1945 29s. HUGHES, E. Quality of I r r i g a t i o n Waters in the Eraser V a l l e y Delta Area. B.S.A. thesis,.Univer-s i t y of B r i t i s h Columbia, 1949 3©. ISRAELSEN, 0. W.., I r r i g a t i o n P r i n c i p l e s and Practices, 2nd Ed. John Wiley and Sons, Inc., New York, 1950 31'. KELLEY, W. P. A l k a l i S o i l s : Their formation, Properties. and Reclamation. Reinhold Publishing. Corporation, New York, 1951 32. , BROWN, S. M., and LIEBIG, G. F. J r . , Chemical effedts of saline i r r i g a t i o n water on s o i l s . S o i l S c i . 49: 95-107, 1940 33. KRAMER, P. J., Plant and S o i l Water Relationships. , McGraw-H i l l Book Company Inc., Toronto, 1949 8 2 . 34. LSAMER, R. W, , and SHAW? B. T., A simples apparatus f o r measuring n o n - c a p i l l a r y p o r o s i t y o n an extensive s c a l e . Jour. Am. Soc. Agron. 3 3 : 1 0 0 3 - 8 , 1941 3 5 . LEER, J . J . , The importance of sodium f o r p l a n t n u t r i t i o n : IV. In f l u e n c e of n i t r a t e f e r t i l i z e r on-the e q u i l i b r i u m • o f c a t i o n s ' i n fodder beet. S o i l S c i . 6 3 : 4 7 9 - 8 6 , ' 1947 35a. LOOMS, W. E., and S h u l l , " C . A., Methods i n P l a n t Phys ft ology. McGraw-Hill Book Co. Inc.J ' New York and London, 1937. 36. 1 LUNT, 0. R., and NELSON, W. L., Studies on the value of sodium i n the m i n e r a l n u t r i t i o n of c o t t o n . S o i l S c i . Soc. Am. Proc. 15: 195 - 2 0 0,"1950 >7. MAGISTAD, 0. C., P l a n t growth r e l a t i o n s on s a l i n e and a l k a l i s o i l s . Bot.- Rev. H : 181-230, 1945 3 8 . , AYERS, A. D., WADLEIGH, C.E.,'and GAUCH, H.G., E f f e c t of s a l t c o n c e n t r a t i o n , kind of s a l t , and clim a t e on plant growth i n sand c u l t u r e s . P l a n t P h y s i o l . 1 8: 151-66,1943 3 9 . , and CHRISTIANSEN, J . E. S a l i n e S o i l s : T h e i r ' .-Nature and Management. U.S. Dept. A g r i c . C i r c . Ho. 707, 1944 40. , P l a n t growth r e l a t i o n s on s a l i n e and a l k a l i s o i l s . : B o t . Review XI: 1 8 0 - 2 3 0 , 1945 41. and REITEMEIER, R. F., S o i l s o l u t i o n concentra-t i o n s at the w i l t i n g p o i n t and t h e i r c o r r e l a t i o n with p l a n t growth. s o i l S c i . 5 5 : 351 - 3 6 0 , 1943 42. MULLIS0N, W. R., and MULLIS0N,.E., Growth responses of b a r l e y s e e d l i n g s i n r e l a t i o n to patassium and sodium n u t r i t i o n . P l a n t P h y s i o l . 17: 632-44, 1942 43. MYERS, A.T., DYAL, R. S., and BORLAND, J . W. The flame photometer i n s o i l and pl a n t a n a l y s i s . P roc. S o i l S c i . Soc. Am. 12: 127 . -30, 1947 44. PETERSON, A. E., and BERGER, K. C., E f f e c t of magnesium on the q u a l i t y and y i e l d of canning peas. S o i l S c i . Soc. Am. Proc. 1 5 : 2 0 5 - 0 8 , 1950 8 3 . 45. ; PIERRE, W.H., and BOWER, C.A., Potassium a b s o r p t i o n by p l a n t s as a f f e c t e d by c a t i o n i c r e l a -t i o n s h i p s . S p j i S c i . 5 5 : , 23-J6, 1.94 3 4 6 . PLICE, M.J., Some e f f e c t s of s a l t water on s o i l f e r -> - • • t i l i t y . Proc. S o i l S c i . Soc. Am. 14: 275-78, 1949 47. PROCEEDINGS FIRST IRRIGATION CONFERENCE LOWER MAIN-. LAND OF BRITISH COLUMBIA. U.B.C. L i b r a r y , Mar. 21, 1952 48. REITEMEIER, R.R., and WILCOX, L „ V . r A c r i t i q u e of e s t i m a t i n g s o i l s o l u t i o n c o n c e n t r a t i o n from the e l e c t r i c a l c o n d u c t i v i t y of s a t u r a t e d s o i l s . S o i l S c i . 61: 281-93, 1946 49o RICHARDS, L. A., ed., The Diagnosis and Improvement of S a l i n e and A l k a l i S o i l s . U.S.D..A. Regional S a l i n i t y L a b oratory, R i v e r s i d e , C a l i f o r n i a . 157 pp., 1947 50. , Methods of measuring s o i l moisture t e n s i o n . S o i l S c i . 68: 95-112, 1949 51. , and WEAVER, L.R., Fifteen-atmosphere percen-. tage as r e l a t e d to the permanent, w i l t i n g percentage. S o i l S c i . 5 6 : 331-39, 1943 ^2. RUDOLFS, Willem, I n f l u e n c e of water and s a l t s o l u t i o n s upon a b s o r p t i o n and germination of seeds S o i l S c i . 20: 15-37, 19 25 ; 53. - RUSSELL, S i r E . J . , S o i l C o n d i t i o n s and g i a n t Growth. 8th Ed. Longmans, Green and Co., Toronto, 1950 54. SAYRE, C . B . , and SHAFER, J . I . J r . , E f f e c t of s i d e d r e s s i n g s of d i f f e r e n t sodium and n i t r o -< genous s a l t s on y i e l d of beets. Proc. Amer. Soc. Hort. S c i . f o r 1944. 4 4 : 453-6, 1944 55. SCHOLLENBERGER, E . J . , and SIMON, R.H., Determination - of: exchange c a p a c i t y and exchangeable bases i n s o i l s -- ammonium acetate method. S o i l S c i . 59: 25-3-7 , 1945 56%, SCOFIELD, C-.S.', The s a l i n i t y of i r r i g a t i o n water. Ann. Rpt. Smithsonian I n s t . 1 9 3 5 * p.2 7 5 , 19 55 8 4 . 57. SHTVE, J. W, The effect of salt concentration on the germination of seeds. H.J. Agr. Exp. Sta. 3 8 t h Ann. Rpt. pp. 4 5 5 - 5 7 , 1517 58. SMITH, R. M., BROWNING, D.R., and POHLMAN, G.G. Labo-ratory percolation through undisturbed s o i l samples in r e l a t i o n to pore size d i s t r i b u t i o n . S o i l S c i . 5 7 : 1 9 7 - 2 1 3 , 1944 59. 6 0 . 6 1 . 6 2 , 6 3 . 64, STEWART, J., and van RYSWYK, A. L., Quality of I r r i g a t i o n Waters i n the Eraser Valley Delta Area. B.S.A. thesis, University of B r i t i s h Columbia, 1 9 5 0 SWINDALE, L. D., and FIELDS, M., Rapid semimicromethod for cation exchange capacity of clays and s o i l s with the flame photometer. S o i l S c i . 74: 287-90, 1952 THORNE, D.W., and PETERSON, H. B., Irrigated S o i l s . The Blakiston Co., Philadelphia and Toronto, 1949 VEIHMEYER, F. J., and HENDRIOKSON, A. H., Methods of measuring f i e l d capacity and. permanent w i l t i n g percentage of s o i l s . S o i l S c i . 68: 75-94, 1948 ?/ADLEIGH, C.H., and GAUCH, H. A., The., influence ofhigh concentrations of sodium sulphate, sodium-chloride, calcium chloride, and magnesium ,chloride on the growth of guayule in sand culture. S o i l S c i . 5 8 : 399-403, 1944 and MAGISTAD, O.C., Growth and Rubber 6 5 . 6 6 . 6 7 . Accumulation i n Guayule as Conditioned by S o i l S a l i n i t y and I r r i g a t i o n Regime. U.S. Dept. Agric. T ech. B u l l . 9 2 5 : 34 pp, 1 9 4 6 and AYERS, A. D., Growth and biochemical com-position of bean plants as conditioned by s o i l moisture tension and s a l t concentra-t i o n . Plant Physiol. 2 0 : 1 0 6 - 3 2 , 1945 GAUCH, H.G., and KOLISCH, M., Mineral com-position of orchard grass grown on Pachappa Loam sa l i n i z e d with various s a l t s . S o i l S c i . 7 2 : 2 7 5 - 8 2 , 1 9 5 1 , and STRONG, D. G., Root penetration and moisture extraction i n saline s o i l by crop plants. S o i l S c i . 6 3 : 341-49, 1947 85. 68. WESTERHOiT, J . J . , R e s t o r a t i o n of the s t r u c t u r e of inun-dated areas i n the Netherlands. I n t . Cong. S o i l S c i . Trans. 1:415-18, 1950 69. WILCOX, J . C., Determination of e l e c t r i c a l c o n d u c t i v i t y of s o i l s o l u t i o n . S o i l S c i . 63. 107-17, 1947 7 0 . WILCOX, L. 7 . , The Q u a l i t y of Water f o r I r r i g a t i o n Use. U.S. Dept. A g r i c . Tech. B u l l . 962: 38 pp, 1948 71. ZUIR, A. J # > Drainage and r e c l a m a t i o n of lakes and of ..the Z u i d e r z e e . S o i l S c i . 74: 75-89, 1952