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A chemical examination of normal and degraded profiles in Glenmore clay Spilsbury, Richard Hugh 1934

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A CHEMICAL E X A M I N A T I O N 07 NORMAL AND DEGRADED PROFILES IN GLENMORE OLAY "by R i c h a r d Hugh 3p i I s b u r y A T h e s i s s u b m i t t e d f o r t h e Degree of MASTER 0? 'SCIENCE IN AGRICULTURE i n the Department of AGRONOMY The U n i v e r s i t y o f B r i t i s h Columbia OCTOBER 1934 Acknowl edgments The writer wishes to acknowledge the f r i e n d l y c r i t i c i s m of Dr. D. G. l a i r d , under whose o f f i c e this work was carried out. Acknowledgment i s also due to Dr. Harris of the Department of Horticulture and Dr. Archibald of the Department of Chemistry for h e l p f u l suggestions. Table of Contents 1. Introduo t i on Pages 1 - 2 2. History 3 - 4 3, Climate 5 - 6 4. Geology 7 5* S o i l and Topography 8 - 10 6 «> Objec tive 11 -7. S o i l Reaction 12 - 13 8. Methods of Analysis 14 - 17 9, Experimental Date 18 - 24 10. Di sous s i on 25 - 27 XX ® Appendix X2s B i b l i ography IABLES i . p.H. by quinhydrone Page 12 2. Water soluble consti tuents (parts per million) 18 3. Exchangeable Cations 4. 'Millequivalents Expressed as Percent of Total S value 23 5. Ratio of Exchangeable Calcium to Sodium 24 A Chemical Examination of Kormal and Degraded P r o f i l e s i n Glenmore Glav - Introduction -B r i t i s h Columbia i s an extremely mountainous province i n which ag r i c u l t u r a l lands are li m i t e d to more or less narrow valleys. As a result of the very variable topography and the extremes of a l t i t u d e found, the climate of necessity must also be variable. Along the coastal regions a humid climate prevails. However, once east of the Coast Range mountains, the climate rapidly changes to a semi-arid nature. A large proportion .of the arable land l i e s within this semi-arid climate, but due to moderate temperatures agriculture may be carried on without the aid of i r r i g a t i o n . These conditions, however, do not hold i n the southern portion of the Province. Here the summers are hot, the balance between evaporation and p r e c i p i t a t i o n narrows, with the result that p r o f i t a b l e agriculture can only be carried on with the aid of i r r i g a t i o n . The farming of this area i s very specialized, the production of tree f r u i t s accounting f o r a very large proportion of the income derived. In a l l specialized crop d i s t r i c t s , land values are high, costs of production are correspondingly high, so that s o i l problems, when they occur, are of a serious nature. The Glenmore Valley i s an important tree f r u i t growing community situated i n this semi-arid climate. In this d i s t r i c t an important soi 1 problem awaits solution. The predominating s o i l i s a heavy clay. Within t h i s one s o i l type, however, there i s a great v a r i a t i o n i n productiveness. In the w e l l drained areas the s o i l i s highly pro due tive and responds nicely to good c u l t u r a l practice. This phase of the clay p r o f i l e may be termed normal. Unfortunately a considerable proportion of t h i s clay area i s not productive. I t i s not amenable to c u l t i v a t i o n . I t runs together when wet and on drying bakes badly, forming an impermeable surface crust. Introduo tion -contd-I t has developed under poorly drained conditions. This phase may be termed degraded. Above - The normal phase showing a young pear orchard i n a healthy condition. Right -Degraded phase. Note the baked and cracked surface - History - - 6 -Prom the old s e t t l e r s i n the valley, i t would appear that even before i r r i g a t i o n , degraded or i n f e r t i l e areas of clay were present. Some of these areas when f i r s t planted to f r u i t trees produced seemingly healthy trees, but as the roots spread out the f i r s t growth was not maintained and eventually many of the orchards were given up. WLth the advent of i r r i g a t i o n many of these degraded areas have increased i n s i z e , so that after twenty odd years of i r r i g a t i o n new orchards are beginning to f e e l the effect of this degradation. However, the noteworthy point seems to be that i r r i g a t i o n i s not the cause of t h i s condition since i t existed long before the water system was l a i d on but rather, that i r r i g a t i o n has aggravated a condition that has been present f o r many years. The area of clay i n the valley i s 2,830 acres (1) or 55% of the t o t a l arable land. The area of the degraded phase i s i n d e f i n i t e . In surveying the d i s t r i c t i t was so often found that the normal and the degraded phase gradually merged one into the other so that no de f i n i t e boundary could be placed around each phase. This degraded phase presents a real problem to those farming this soiL In many cases the f r u i t trees are dying out or show such poor growth as to become stunted and unproductive. In some cases the orchards have been abandoned and the land devoted to grazing. There i s one instance where the land i s barren, supporting no vegetation whatsoever. In the less extreme cases the orchards have a starved appearance and d i f f i c u l t y i s 11) Compiled from "The S o i l Survey of Glenmore Area" Department of Agriculture, V i c t o r i a , B.C. History -contd-found i n maintaining cover crops. Many farms contain a portion of successful reclamation would benefit - 4 -this degraded phase so that any a very large number of f r u i t growers. The Degraded Phase Showing* Dying Out Fruit Trees. - Climate - - 5 -The climate f o r this d i s t r i c t i s semi-arid. The following graph i l l u s t r a t e s an 18 year average of the mean monthly temperature and pr e c i p i t a t i o n f o r Kelowna (2). figures f o r the r e l a t i v e humidity are not available f o r Kelowna so those for Vernon are shown graphically. Vernon has a very similar climate to kelowna. /.so T& 1^-1 f*£ FZATU K £ A O Q ± 0.7SL 35 aso r BO % S O I 70 L eo 150 4 0 The average mean temperature varies from 25 degrees F i n January to 67 degrees F i n July. The maximum temperature recorded i n 1932 was 93 degrees F, The mean monthly p r e c i p i t a t i o n varies from 0.5? inches i n July to 1.59 inches i n December. The t o t a l r a i n f a l l and snowfall i s 11.47 inches f o r the eighteen year average. There i s a remarkably even d i s t r i b u t i o n throughout the seasons. The r e l a t i v e humidity, as would be (2) "Climate of B r i t i s h Columbia" Department of Agriculture, V i c t o r i a , B.C. 1932 Climate -contd- - .6 -expected, varies with the p r e c i p i t a t i o n and the temperature. The average r e l a t i v e humidity f o r the year i s 70%. The humidity i n coast climates varies from 60a/0 to 90$. Under these climatic conditions, evaporation w i l l equal or exceed p r e c i p i t a t i o n . This i s borne out i n the s o i l p r o f i l e s of the d i s t r i c t for i n no case i s a podsolic condition found, while there i s plenty of evidence of a lime accumulation i n the "B" horizon, G. V. Jacks (3) points out that the accumulation of calcium carbonate i n the sub surface s o i l can only take place where the downward movement of water i n the moist season i s counterbalanced by the upward movement i n the dry season. This i s a chara c t e r i s t i c of the chernozem, or semi a r i d climate. 13) S o i l , Vegetation and Climate. Tec. Communication Ho. 29 Imp* Bur. of So. So* 1934 - Geology «- - 7 -The geology of this d i s t r i c t has been very adequately summarized by Mr G. 0. Eelley i n his report on the " S o i l Survey of the Glenmore Area." Very b r i e f l y , with the decay of the Cordilleran g l a c i e r , large deposits of boulder clay were l e f t at elevations of 3,000 to 5,000 feet above the present sea l e v e l . Subsequent erosion resorted much of this g l a c i a l t i l l and deposited i t i n slowly moving or s t i l l water. As two invasions of the sea are known to have taken place following the C o r d i l l e r a n g l a c i e r , i t i s probable that the intensive plated clay deposits found i n the Okanagan Valley are the resuit of the deposition of the eroded clay i n the arms of the sea. The d e f i n i t e l y varired character of the clay formation points to such an o r i g i n . - S o i l and Topography - - 8 -I t has already been pointed out that the s o i l s l i e i n a valley. This valley i s almost saucer shaped for the gradient throughout i t s length i s s l i g h t and i s i n s u f f i c i e n t to carry off the excess ground water when percolating through a heavy clay s o i l . Such a condition then produces a high water table through the centre of the valley. I t i s i n t h i s area that the degraded phase f i r s t became apparent. The normal phase i s found on the well drained slopes. These two phases merge, one into the other, where drainage becomes the l i m i t i n g factor. The following analysis by the Bouyoucos method (4) shows the composi-tion of thi s s o i l . Normal phase Total c o l l o i d s Sand S i l t 01ay "A" horizon 81.6$ 6.4$ 48.0$ 45.6$ "B" horizon 88.0$ 2.0$ 50. $ 48.$ . "G" horieon 83.2% 4.8$ 26.0$ 69.2$ Degraded phase "A'* horizon 76.0$ 12.0$ 26.0$ 62.0$ "B" horizon 82.0^ 10.0% 14.0$ 76.0$ The Bouyoucos Method did not prove satisfactory f o r the analysis of these clays. Great d i f f i c u l t y was found i n obtaining dispersion of the clay p a r t i c l e s . Sodium hydroxide, sodium oxalate, ammonia and hydrochloric acid as dispersing reagents were inadequate. The best results were obtained from using sodium carbonate and dispersing f o r half an hour. The above figures are inserted i n order to give an idea of the texture of the s o i l . They show very conclusively that the s o i l i s of an extremely heavy nature 14) A comparison of the Hydrometer Method and the Pipette Method f o r making Mechanical Analysis with New Directions, J r . Am. Soc. Agron. 23 No. 4 G. Bouyoucos 1930. S o i l & Topography -Contd- - 9 -i n which tho c o l l o i d a l f r a c t i o n averages about 80$. These figures would indicate that the degraded phase was higher i n clay than the normal phase. However, a s u f f i c i e n t number of analysis were not made to J u s t i f y any such broad generalization. Description of P r o f i l e The normal "A" horizon i s about 7 inches i n thickness and i s a medium brown colour. I t tends to form clods which pulverize easily by hand to a crumb structure. I t i s a well flocculated s o i l and i t s structure i s such that i t works into a good t i l t h under c u l t i v a t i o n . The "A" horizon of the degraded phase i s darker i n colour. I t also forms clods but does not break down e a s i l y , i t s consistency i s tough and resistant to pulverising. With c u l t i v a t i o n these clods do not break down but bake into hard lumps. Under i r r i g a t i o n this s o i l runs together, making water penetration slow and subsequent c u l t i v a t i o n d i f f i c u l t . This s o i l i s i n a highly dispersed state. The normal "B" horizon is' about 18 inches i n thickness and i s a medium brown colour. I t has a de f i n i t e jointed columnar structure, characteristic of solonetz or a l k a l i s o i l s . The columns, however, are f r i a b l e and break down to a coarse nut structure. Scattered throughout the horizons are calcium carbonate concretions. The corresponding degraded horizon i s again darker i n colour. The columnar structure i s present, but tends to be more run together and less d i s t i n c t . I t i s tough when moist and does not break down easily. The "G" horizon of both phases i s similar. The colour i s a l i g h t grey brown. I t i s of a definite plated structure and extremely tough. S o i l & Topography -contd- " 1 0 The plates are about a quarter of an inch i n thickness. On drying t h i s horizon bakes into very hard b r i t t l e sheets. This horizon also contains lime concretions. The plates appear to be impervious to the downward move-ment of water. In some of the p r o f i l e s examined the lower part of the "BM and the upper two fSet of the "GH contain rosettes of sa l t c r y s t a l s . These cr y s t a l s l i e i n pockets i n the "B" end between the upper plates of the "C" horizons. In the samples selected for chemical analysis no accumulations of salt c r y s t a l s were noticed. Trench Showing the P r o f i l e of the Normal Phase. - The Objective - - 11 -As has already been pointed out, the normal and the degraded phase of this clay p r o f i l e have vastly different physical properties. Both these phases frequently appear i n the same orchard so that one must conclude that the physical differences are not due to cu l t u r a l practices but must be due to some chemical property associated with one of these phases. The object of th i s investigation, then, i s to determine the chemical characteristics of each phase and to determine, i f possible, an essential difference that would account f o r the adverse physical condition of the degraded phase. By this method i t i s hoped that a basis w i l l be arrived at upon which to b u i l d up a reclamation programme. The hydrogen ion concentration of the s o i l solution gives a valuable clue as to the nature of the s o i l . This was the f i r s t determination made. A complete chemical analysis i s a long and tedious procedure and i t i s doubtful i f the results would j u s t i f y the time spent on making i t . I t w i l l be remembered that the degraded phase developed from the normal phase through adverse drainage conditions. This fact would lend one to believe that this degradation was caused by water and by sa l t s held i n solution. For this reason then, the analysis of the s o i l moisture was considered essential. Associated with soluble salts are those bases that are held i n the base exchange complex. I t seemed necessary, then, that the investigation should include exchangeable base analysis. S o i l Reaction - - 12 -The s o i l reaction i s an important feature i n any investigation. In semi-arid s o i l s the reaction i s nearly always on the alkaline side. However, there i s a l i m i t to the a l k a l i n i t y , above which plants w i l l not grow. The a l k a l i n i t y i s the result of carbonates generally. Calcium carbonate or lime i s rarely toxic to plants and when present alone, w i l l not give a p.H. value above 8.4. Sodium carbonate i s toxic to plants when present i n excess. In terms of p.H. values, an excess i s present when the reaction i s above p.H. 8.4. As a test f o r carbonates, the s o i l s were treated with Hcl acid and effervescence noted. The following table shows the reaction of the two phases of the clay. Table 1. pH by quinhydrone Effervescence Extraction (a) In v/ater I. N. E.G1. wi th HCL Eormal "A" 7.6 7.5 6.5 Ko 11 M g l l 7.5 ' 7.6 • . 6.9 Yes <l f lQM 6.65 7.5 7.0 Yes Degraded "A" 7.6 ; 7.4 6.7 m 7.65 7.4 6.7 Yes Ii Ilfjfl 7.5 7.6 7.1 Yes In the extraction method the s o i l was moistened to a puddled state allowed to stand twenty-four hours, s t i r r e d , and the moisture extracted by a Livingston atmometet with suction. This method was used to obtain an extract corresponding as nearly as possible to natural s o i l moisture (a) Determinations made by J.C.Wilcox, Summerland Experimental Station. S o i l Reaction -contd- - 13 -conditions. The second method consisted i n taking the pH of a 1 i 2 s o i l water mixture after half an hour's standing. A 1 N. KC1 solution was added i n a 1 : 2 r a t i o i n the third method and the pH determined after half an hour's standing. From Table 1 i t w i l l be seen that the normal and the degraded s o i l s have a very similar reaction. In no case does the pH approach the toxic a l k a l i n e l i m i t ; on the contrary, the reaction would indicate a favourable condition f o r plant growth. Such a condition would point to an absence of basic s a l t s such as sodium carbonate. I t i s also noticeable that the reaction does not increase i n a l k a l i n i t y with depth. In the normal XG1 solution the reaction increases i n a c i d i t y indicat-ing an unsaturated condition of the base exchange material. No deter-mination of exchangeable hydrogen was made so that these figures are no in d i c a t i o n of the degree of unsaturation. I t w i l l be noticed that the absorbtion complex seems to be more nearly saturated with bases i n the lower horizons. This i s probably due to the greater concentration of lime i n the "B" and "G" horizons. The most significant point seems to be that the degraded phase shows no greater unsaturation than the normal phase. The -effervescence with HC1 acid indicates the presence of insoluble carbonates i n the "B" and "C" horizons of both s o i l s . The "A" horizon appears to be largely leached of carbonates, accounting to the accumulation i n the "B" and "C" horizons. This test has significance f o r i t l i m i t s the methods for base exchange procedure to those adaptable to carbonate s o i l s . - Methods of Analysis - • - 14 _ A 5 j 1 r a t i o of water to s o i l was used for obtaining a s o i l solution. A 2:1 r a t i o was t r i e d , but due to the extremely heavy nature of the s o i l , the resulting extracts were i n s u f f i c i e n t for analysis unless very large quantities of s o i l were to be used, A wider r a t i o than 5 ; 1 was avoided as there i s then a p o s s i b i l i t y of replaceable sodium coming into solution due to hydrolysis ( 5). The extract was obtained by shaking 200 grams of s o i l with a l i t r e of d i s t i l l e d water i n a Winchester bottle for twenty minutes. The solution was allowed to stand f o r some hours, then decanted on a Buchner funnel. The extracts were clear and colorless? about 600 c.c. being obtained. This proved satisfactory for a l l but the two "A" horizons. In the case of the two "A" horizons, the extracts contained large amounts of c o l l o i d a l clay. A clear solution was obtained by r e - f i l t e r i n g the extract through the o r i g i n a l decanted clay, but t h i s process consumed too much time even with the aid of suction. The method f i n a l l y adopted was f i l t e r i n g by the use of a porcelain pressure f i l t e r . The extracts were clear but of a greenish colour due to dissolved organic matter. For the standard methods of analysis followed, W.W.Scott [6) A.A. Uoyes (7) and the A.O.A.C. (8) were consulted. Potassium said sodium were determined i n d i v i d u a l l y , by more recent methods. (5) Sodium hydroxide rather than sodium carbonate the source of a l k a l i n i t y in'black a l k a l i soils.J.F.Breazeale and W.T.McGeorge, University of Arizona Tec. Bui. 13 1926. {6) Standard methods of chemical analysis W.W.Scott 1927. ( 7) Qualitative Chemical Analysis A.A.Soyes 1925 (8) Methods of Analysis Association of O f f i c i a l A g r i c u l t u r a l Chemists 1919. Methods of Analysis -contd- - 15 -Potassium was determined gravimetrically as potassium c o b a l t - n i t r i t e as outlined by J . X. Steenkamp (9) while sodium was precipitated as sodium zinc uranyl acitate according to Lang and Muck (10) with the modification that p r e c i p i t a t i o n took place i n an a l c o l h o i i c rather than aqueous solution. No en t i r e l y satisfactory method has been devised f o r determining the exchangeable cations, i n s o i l s containing soluble s a l t s i n amounts commonly found i n a r i d s o i l s . This i s especially true of saline s o i l s . Irrespective of the displacing s a l t used, the displacing solution i t s e l f w i l l dissolve some of the soluble s a l t s i n the s o i l solution. The r e s u l t , of course, w i l l be the sum of the exchangeable bases plus the bases dissolved i n the displacing solution. In the case of saline s o i l s , leaching with d i s t i l l e d water f i r s t w i l l remove the soluble s a l t s . However, as the salts are not equally soluble, this leaching with an excess of water w i l l bring s a l t s i nto solution i n a different proportion to that found i n the natural s o i l solution, hence the result w i l l be that a new equilibrium must be established between the exchangeable bases and the leaching solution. That i s , the leaching solution i t s e l f w i l l act as a displacing solution, so that the exchangeable bases eventually found w i l l not be i n the same proportion or amounts as o r i g i n a l l y present. For determining the replaceable bases i n carbonate s o i l s , Gedroiz (11) suggests estimating the carbonates present before and after leaching with (9) Micro Chemical Analysis of Soi l s - J.L.Steenkamp. Second Internation-a l Congress of S o i l Science 1930. (10) Iodometric Determination of Sodium as sodium zinc uranyl acetate. B.Lang, G.Muok. Ztschr. Anal. Chem. 93 1933 p 100 - 102 Reported i n Recent Developments i n S o i l Analysis Ho.4 Imperial Bureau of S o i l Science, Harpenden. ,. . +Vi__ (11) Contribution to the Method of Determining the z e o l i t i c bases i n tne s o i l K.K.Gedroiz. Zhur. Opit.Agron 19: 226-244 1918. Keportea i n prin c i p l e s governing the r e g l a m a t i o g . o f a | _ k | l i 8 ^ i l s 5 W . ^ | l l e y & S.M. Methods of Analysis - 1 6 --contd-the displacing solution, the difference may then be attributed to dissolved carbonates, T j u r i n (12) recommends t i t r a t i n g the displacing solution a f t e r percolation with 0.02 K. HC1 using methyl orange as an indicator to determine the dissolved carbonates. Both of these methods f a i l to show the proportions of calcium and magnesium dissolved as carbonates. The method used i n t h i s investigation i s one advanced by Magistad and Burgess (IS). An alcoholic s a l t solution i s used as the displacing solution. The s o l u b i l i t y of calcium and magnesium carbonate i s extremely small i n such a solution. This, however, i s only true of carbonates, the s o l u b i l i t i e s of chlorides, sulphates and s i l i c a t e s being l i t t l e affected. The following i s a brief outline of the method used. The displacing solution was a 0.1 N. BaClg.211^0 solution i n a mixture of approximately 75^ o ethyl and 25% methyl alcohol diluted with d i s t i l l e d water to a specific gravity of 0.875. 25 grams of the s o i l was leached with 125 c.c. of d i s t i l l e d water. The s o i l was then shaken with a l i t r e of neutral alcoholic barium chloride solution and allowed to stand overnight. No d i f f i c u l t y was experienced i n obtaining a clear f i l t r a t e through a Buchner f i l t e r . The alcohol was then d i s t i l l e d off and the volume made up to 200 c . c . Tests showed that 25 c o . (12) Method of Determination of Exchangeable Calcium and Magnesium i n s o i l s containing a l k a l i n e earth carbonates I.W. Tjurin - La Pedologie 22:5 - 24 1927. Reported i n p r i n c i p l e s governing the reclamation of A l k a l i s o i l s W.P.Kelley & S.M.Brown Hilgardia ;8 No, 5 1934. 113) The use of Alcoholic Salt Solutions for the Determination of replaceable bases i n calcareaus s o i l s . O.C.Magistad and P.S.Burgess University of Arizona Tec. Bui. 20 1928. Methods of Analysis -contd- - 17 -samples were s u f f i c i e n t f o r analysis. The methods of analysis are given by Burgess and Breazeale (14).. The barium i s precipitated from an acetic acid solution with potassium chromate. Calcium i s precipitated from the f i l t r a t e as calcium oxalate and determined volumtrically by dissolving i n sulphuric acid and t i t r a t i n g with 0.1 K. EMnO^. Magnesium was precipitated with ammonium acid phosphate anl determined gravimetrically by i g n i t i n g and weighing as MggPgO?. Sodium and Potassium were determined i n the o r i g i n a l barium chloride percolate. The alkaline earths were precipitated by ammonium sulphate and sodium and potassium determined i n the f i l t r a t e by the methods previously outlined for the analysis of the s o i l solution. (14) Methods f o r determining the replaceable bases either i n the pres or absence of a l k a l i s a l t s . P.S.Burgess and J.i'.Breazeale, Univ. of Arizona Tec. Bui. 9 1926. - Experimental Data - 18 In presenting tables i t i s frequently the custom to express the results i n terms of . millequivalents. This method has decided advantages when a complete analysis i s made. However, when possible acid radicals or bases are omitted, there appears to be no benefit by t h i s style of present-ation, hence the more common method of expressing the water soluble constituents i n parts per m i l l i o n has been followed. Table 2 Water Soluble Constituents (parts per million) Nor. A Beg, A Ror.B D9g. B Nor. C Deg. C Na 0 .-• 2 163 705 804 1180 1020 K 0 112 100 52 55 26 83 •OaO-V 45 , 310 518 2800 980 4100 MgO 7300 1«9 8350 1750 715 3780 SO 990 325 2300 8750 3850 5630 P 0_- 6 '. , 4 2 1 3 3 CO ' 2 323 264 312 206 268 236 01 56 107 66 61 126 58 An examination of this table shows that i n both phases there i s a leaching of bases from the "A" to the " B " horizons with the exception of potassium. The leaching continues from the " B " , for the "C" horizon appears to be the horizon of greatest accumulation. This seems contrary to the accepted fact that the " B " horizon i s the area of accumulation. However, the cause i s probably f a u l t y sampling, due to the fact that these horizons are not d i s t i n c t l y separate but merge one into the other. I t i s i n t h i s t r a n s i t i o n layer that the rosettes of salt c r y s t a l s sometimes Experimental Data -contd- - 19 -appear. I t i s suggested, then, that the "G" horizon contains an inch or so of what should be »B" and that i n th i s overlap there i s the s a l t accumulation. That potassium should decrease with depth i n spite of leaching i s quits common. The explanation i s that decaying vegetation i s continually returning potassium to the surface s o i l which o r i g i n a l l y was drawn from the "A" and "B" horizons. I n comparing the normal versus degraded s o i l s i t would appear that sodium does not play a distinguishing part. Potassium seems to be present i n s u f f i c i e n t amounts for plant growth i n both s o i l s . The figures f o r calcium and magnesium are noteworthy; calcium being highest i n the degraded pha.se and magnesium i n the normal. I t i s suggested that o r i g i n a l l y the s o i l contained a high magnesium calcium r a t i o . The calcium would leach from the surface downward as the soluble bicarbonate and much of i t would be removed i n the natural under ground water. As the normal phase i s from a well drained area there would be no tendency for the ground water to r i s e , and bring back soluble carbonates. This does not preclude the p o s s i b i l i t y of some returning by c a p i l l a r y water but i t does account f o r excessive amounts of soluble calcium being absent from the normal phase. Magnesium was also leached from the "A" to the "B" but due to i t s greater concentration, i t was not removed to the same extent as calcium. The figures from Table 2 might suggest that magnesium was present i n the solum i n crystaline form, having been deposited from a highly saturated solution. The degraded phase shows an opposite condition. This also can be Experimental Data -contd- - 20 -explained by the theory already advanced. The degraded phase, i t w i l l be remembered, developed under conditions of poor drainage and consequently a high water table. The calcium was leached downward as the soluble bicarbonate where i t joined the ground water. This ground water was probably already charged with soluble calcium leached from the well drained normal phase, i n the spring the melting snows increased the normal run off so that consequently the water table rose, carrying with i t soluble calcium. On nearing the surface the tendency would be for carbon dioxide to be given off with the result that calcium would be precipitated out as the carbonate and hence would accumulate near the surface. Magnesium sa l t s would also r i s e with the water table but due to their greater s o l u b i l i t y would recede with the f a l l of the water table, thus there would be l i t t l e tendency f o r magnesium salts to accumulate i n the »B" horizon. IS i s noticeable that magnesium, l i k e calcium, i s largely leached out of the "A" horizon. Of the acid r a d i c l e s , sulphates predominate. Again this leaching of the "A" horizon of the degraded phase i s noticeable. There i s a higher concentration i n the »B" than the "C" horizon, i n this phase. The normal phase shows a continuous accumulation with depth indicating a gradual leaching from the surface down. This i s also true of chlorides i n the normal phase. The degraded phase shows a decreasing concentration of chlorides with depth. This may be due to the c a p i l l a r y r i se of moisture. The s o i l samples were taken i n the F a l l of the year, at a time when the effects of evaporation are most noticeable. Under these conditions the most soluble salts would concentrate at the surface, while the less soluble salts would be deposited at greater Experimental Data -contd- - 21 -depths. In the degraded phase then, the soluble chlorides would concen-trate at the surface while the less soluble sulphates would accumulate i n the "B'V and "C" horizons. Table 2 seems to bear this reasoning out. The carbonate content of both s o i l s shows l i t t l e difference due to depth. From Bi Gleria's experiments ( 3-5) the carbonate content as found i n Table 2 i f present as calcium carbonate, would express the maximum s o l u b i l i t y at a p.H. of 7.6. This would account for the uniform results obtained. If the carbonate had been present as sodium carbonate then an accumulation of carbonates would have been found i n the "B" and "0" horizons. This i s not the case. In a preliminary test f o r carbonates, both s o i l s showed an effervescence with hydrochloric a c i d , i n the "B" and "C" hori zons. This would indicate a reserve of insoluble carbonates and would stamp both s o i l s as being calcarious. Base Exchange The proportion of the various bases absorbed i s believed to be the result of chemical e q u i l i b r i a e xisting between the ionized s o i l solution and the absorbtion complex. I t i s obvious then that a study of the s o i l solution presents only a part of the picture and that for a f u l l under-standing, s o i l solution and base exchange studies must be made. The following table presents the exchangeable base analysis. {15) J . Di Gleria. Reclamation Experiment on Hungarian Alkaline Soils 1929. Kiserletugyi Eozl Vol. 32 pg 252-89, Reported by A.A. De Sigmond. The Reclamation of A l k a l i Soils i n Hungary. Imperial Bureau of S o i l Science Technical Comm. No. 23 Experimental Data -contd- - 22 -Table 5 Exchangeable Cations Ca, . Mg. ; Ha. Total S, Exchangeable cations i n millequivalents per 100 gr. s o i l l o r . "A" »B" "0" 14,2 16,5 21,2 10,6 12,3 "13,1 9.2 11.9 14.7 0.5 0.2 0.1 34,5 40.9 49.1 Beg, "A" 13,6 16.0 14.5 0.5 44.6 "B" 13,9 6,6 13.3 0.2 34,0 »C" 10,9 11.0 25.2 0.7 47.8 Table 3 shows some very interesting and significant figures. In the f i r s t place, with the exception of potassium, the exchangeable bases increase wi th depth i n the normal phase, so that the t o t a l S value increases from the "At' to the "0" horizons. This corresponds to Table 2 where the cations of the normal phase increase with depth, magnesium i n the "G" horizon being an exception. In the degraded phase there i s no such uniform-i t y . The S value f o r the "B" horizon i s lower than the value for the "A" horizon and considerably lower than that of the "C" horizon. An examin-ation of the table shows that t h i s order i s not maintained by the Individual cations. Again, a comparison of the cations of Table 2 reveals no correlation with the exchangeable cations. Thus the degraded phase shows an utter lack of uniformity. TMs might be caused by an unbalanced equilibrium e x i s t i n g between the soluble and exchangeable cations. Ho determination was made for absorbed hydrogen. However, the lowering of the p.H. value i n the EC1 solution (Table 1) would not indicate a greater unsaturati on i n the degraded than i n the normal phase. The following table shows the various bases making up the t o t a l Experimental Data -contd-Table 4 Millequivalents Expressed as Percent of Total S value . Ga. \: Mg. ; l a . K, ,?otal Nor. "A" 41.1 30 • V 26.6 1.6 100 ti "B" 40.4 30.1 29 .1 0.4 100 it •.HQ* ; 43.2 26.5 30.0 0 .3 100 Deg. "A" 30 .3 • . 36,0 32.5 3.© 100 II i ign • 40.9 19.4 39.2 0.5 100 II H(jn 22.8 • 23.0 %)7L o 7 1.5 100 In the normal phase the divalent bases greatly predominate. The proportion of magnesium i s , however, high. The r a t i o of calcium to magnesium i s about 4s3. I t w i l l be noted that the proportion of the i n d i v i d u a l bases remains r e l a t i v e l y the same with depth. In Table 3 i t was shown that i n the normal phase the t o t a l S value increased with depth thus i t i s seen that the increase i n the various cations does, not upset the r a t i o e x i s t i n g between the "A", "B" and "C" horizons. In other words a similar equilibrium exists between the various horizons of the normal phase. The degraded phase shows a si g n i f i c a n t decrease i n the proportion of divalent bases to Sodium. This i s greatly accentuated i n the "G" horizon where sodium comprises 50% of the t o t a l . The proportion of the bases i n each of the three horizons i s d i f f e r e n t , indicating that i n each horizon there i s a different set of condl tions governing the equilibrium existing between the soluble and exchangeable oations. In order to i l l u s t r a t e the essential difference between the normal and the degraded phase of the clay, the calcium sodium rate i s presented Experimental Data -contd-i n which calcium i s represented as 100. Table £ Ratio of Exchangeable Oalclum to Sodium Ca-fta. Normal Degraded "A" horizon 100:65 100:107 "B" horizon 100:72 100: 96 tlQtl horizon 100:69 100:231 I t i s evident that i n the process of degradation calcium has been replaced by sodium i n the exchange complex. I t i s well known that a sodium saturated clay produces an impermeable s o i l . From the above table i t i s seen that i n the degraded phase sodium dominates the absorption complex. I t i s believed, then, that this high proportion of exchangeable sodium i s responsible for the adverse physical condition of the degraded phase. Di sou ssi on - 25 The res u l t s from the analysis of two phases of a clay p r o f i l e may be b r i e f l y discussed. In the normal phase there i s a high concentration of s a l t s i n the "A" and "B" horizons. Magnesium sulphate predominates. There i s l i t t l e evidence of sodium carbonate being present. I t i s probable that the sodium i s present as a sulphate and chloride. There i s a reserve of insoluble carbonates i n the "B" and "0" horizons. The absorption complex contains s u f f i c i e n t divalent bases for the s o i l to maintain a flocculent condition. At the same time sodium i s present i n considerable quantities. The high soluble s a l t content, and an absorption complex containing appreciable amounts of sodium would indicate a saline a l k a l i s o i l (16). In such a s o i l , under i r r i g a t i o n , there would be a gradual leaching out of the soluble sal t s into the lower horizons. This leaching should not produce a degraded a l k a l i s o i l , f o r the s l i g h t l y soluble calcium and magnesium carbonates would then come into solution and replace exchangeable sodium i n the absorption complex. I r r i g a t i o n , coupled with adequate drain-age, would then remove the exchanged sodium as sodium bicarbonate. Thus under conditions of good drainage, i r r i g a t i o n should improve the physical condition of the normal phase of the clay s o i l * The importance of drainage w i l l be more f u l l y emphasized under the discussion of the degraded phase. In the degraded phase there i s evidence of a leached "A" horizon. The soluble salt content i s considerably lower than the salt content of the (16) The c l a s s i f i c a t i o n of a l k a l i and salty s o i l s . De Sigmond International Congress of S o i l Science ¥1 pp 330 1927. Discussion -contd- _ 2 6 . corresponding normal "A" horizon. 2here i s a f a i r l y high salt content i n the "B" and "G" horizons. How-ever, the high calcium content and the r e l a t i v e l y low magnesium content are explained by a fluctu a t i n g water table. That i s , the degraded phase i s a leached s o i l , but due to a seasonal r i s i n g of the water table soluble salts are re-deposited. The greater amount of chlorides i n the surface s o i l again indicates a c a p i l l a r y r i s e of soluble s a l t s . Such a condition i s only possible where a high water table e x i s t s . The impermeable condition of the degraded s o i l i s evidently due to a high content of exchangeable sodium. That this condition has been brought about by the high water table seems probable. With the r i s e of the ground water i n the Spring the s o i l becomes saturated with a saline solution, i n which sodium i s present i n s u f f i c i e n t amounts to replace considerable amounts of calcium and magnesium from the exchange complex. With the subsequent lowering of the water table during the dry season, calcium and magnesium are re-precipitated. Sodium w i l l maintain i t s greatest concentra-t i o n i n the "G'» horizon where the moisture content i s greatest, for i t i s the most soluble s a l t , hence most mobile. During this period, then, the divalent bases w i l l predominate i n the upper horizons and some sodium w i l l be replaced by calcium and magnesium. Table 4 shows the percentage of exchangeable sodium increasing from 32 to 52 percent from the "A" to the "C" horizons. This shows that sodium as a replacing cation increases with depth, and conversely, the divalent bases calcium and magnesium at t a i n greatest proportions nearer the surface. Thus i t w i l l be seen that so long as the water table fluctuates, the exchangeable cations w i l l also fluctuate. I t follows that u n t i l drainage Discussion -contd- - 27 i s provided to remove the soluble sodium, no permanent replacement by the divalent bases i s possible. The impermeable condition w i l l exist then, u n t i l the ground water i s removed to adequate depths or u n t i l drainage i s provided to remove the soluble s a l t s . This s o i l may also be c l a s s i f i e d as a saline a l k a l i s o i l , i n which sodium has gained a dominent p o s i t i o n i n the absorbing complex. Appendix Reclamation Wo attempt w i l l be made to review the numerous publications on the reclamation of a l k a l i s o i l s . Such a procedure would be of l i t t l e value for i n most cases reported, the s o i l amendments found most satisfactory are applicable only to the p a r t i c u l a r s o i l experimented upon. A short discussion of the p r i n c i p l e s underlying the use of the more common s o i l amendments and their a p p l i c a b i l i t y to various a l k a l i conditions w i l l be much more constructive. A. A. de Sigmond (17) divides a l k a l i s o i l s under four headings. 1. Saline s o i l s 2. Saline A l k a l i s o i l s 3. Desalinized a l k a l i s o i l s 4. Degraded a l k a l i s o i l s Bach of these headings may be subdivided as r i c h or poor i n calcium carbonate. In the f i r s t case, saline s o i l s , the a l k a l i n i t y i s due to soluble salts being present i n excess. There i s no accumulation of sodium i n the absorbtion complex, hence leaching out of the soluble s a l t s to a non toxic concentration w i l l bring back the s o i l to a f e r t i l e condition. Under the second heading, saline a l k a l i s o i l s , there i s not only an accumulation of soluble s a l t s , but also a more or less sodium saturated absorbing complex. The normal phase of the clay s o i l under discussion i s c l a s s i f i e d under this heading. In thi s par t i cular case sodium does not dominate, and as w i l l be explained l a t e r the calcium reserve i s su f f i c i e n t (17) The Reclamation of a l k a l i s o i l s i n Hungary. De Sigmond Imperial Bureau of S o i l Science Technical communication Ho. 23 1932. Appendix -c on ta-l l to prevent sodium domination i n the exchange complex. The degraded phase i s also c l a s s i f i e d as saline a l k a l i but i n t h i s case sodium dominates i n the exchange complex. Kelley and Arany (18) point out that where neutral sodium salts accum-ulate, the exchange of bases rarely goes to completion owing to the nature of the equilibrium. That i s , any calcium displaced from the absorbing complex immediately forms a soluble calcium s a l t . This soluble calcium sa l t then exerts a displacing influence on the absorbed sodium. The result i s therefore an equilibrium between the absorbed and soluble calcium. A sodium saturated clay i s thus impossible when this equilibrium exists. However, i f carbonates are present, then the displaced calcium w i l l be precipitated as calcium carbonate. The displacement of calcium may then go to completion. The degraded phase under consideration i s probably an instance of where neutral sodium salt s prevent the complete saturation of the absorbing complex by sodium. By leaching such s o i l s , the desalinized a l k a l i s o i l s would be formed; that i s , de Sigmond's third subdivision. In cases where calcium was present as a soluble s a l t , leaching alone would not produce any beneficial results. The removal of the calcium salt would permit the absorbtion of sodium to go to completion. In this p a r t i c u l a r case, insoluble calcium and magnesium carbonates are present. Where the replaced calcium i s precipitated as carbonates and to a lesser extent s i l i c a t e s , leaching w i l l not remove important amounts of 118) The chemical effects of gypsum, sulphur, i r o n sulphate and alum on a l k a l i s o i l . W.P.Kelley and A. Arany. Hllgardia Vol. 3 14 Univ. of C a l i f o r n i a 1928. Appendix -contd-' calcium from the s o i l . Consequently with the removal of soluble sodium salts by leaching, the small amounts of soluble calcium carbonate present (depending on the s o i l reaction) exert a greater influence on the absorbed sodium. That i s , soluble sodium exerts a protective influence on the absorbed sodium by means of the equilibrium existing, but with i t s removal by leaching, the same amount of calcium present w i l l be proportion-ately greater. This greater proportion of calcium w i l l disturb the equilibrium so that calcium w i l l displace more sodium. I t i s necessary, of course, that the by-products of this reaction be removed by drainage, i f sodium i s to be completely replaced. The reaction i s possibly one of the following (19) Ha-clay GaGO„ o Ca-clay Na CO 2 ; Ha-clay HOH H-clay EaOH H-clay CaC03 Ga-clay H2°°3 H 2C0 s NaOH tto.HC0„ a H 2 ° From the above discussion i t would seem that leaching alone would reclaim the degraded phase investigated. However, due to the extremely heavy nature of the clay s o i l i t Is probable that leaching would proceed too slowly to be i n I t s e l f s u f f i c i e n t . The alternative then, i s to add some s o i l amendment that w i l l greatly increase the proportion of calcium present i n solution. By this external means sodium w i l l be forced out of the absorbtion complex and kept out by the concentration of soluble calcium present. Eventually the replaced sodium w i l l be removed by drainage and the (19.) P r i n c i p l e s governing the reclamation of a l k a l i s o i l s . W.P .Kelley and fi.H.Brown. Hilgardia Vol. 8 No. 5 1934. Appendix T7 -contd-normal soluble calcium content of the s o i l solution w i l l then be able to maintain a calcium saturated exchange complex, I t must be emphasised, however, that the removal of the soluble s a l t content and the replaced sodium i s essential to a permanent reclamation. In this p a r t i c u l a r instance i t embodies not only leaching, but also the s t a b i l i z i n g of the water table at a depth s u f f i c i e n t to counteract any tendency for the water to r i s e by c a p i l l a r y action. As already intimated, the speed of the reclamation i s p a r t i a l l y governed by the amount and s o l u b i l i t y of the calcium sal t s present, (The application of calcium carbonate to calcarious s o i l s hence w i l l be of l i t t l e value, f o r i t s a v a i l a b i l i t y i s determined by the s o i l reaction and not the amount present. The use of gypsum i s twofold. F i r s t , sodium oarbonate i s converted to sodium sulphate and calcium carbonate and second, sodium exchange compounds are converted into calcium compounds and sodium sulphate. The amount of gypsum added must be equal to the sum of the soluble and exchangeable sodium f o r the above reactions take place simultaneously. In order that the exchange may be complete i t i s necessary that the sodium sulphate be removed by leaching. The action of sulphur depends on i t s oxidation to sulphuric acid. The sulphuric acid reacts with the soluble carbonates, absorbed sodium and insoluble calcium carbonates and s i l i c a t e s . That i s , i t w i l l produce a hydrogen clay and at the same time bring into solution calcium as calcium sulphate, so that the net result i s a calcium clay and sodium bicarbonate. Again leaching must remove the soluble sodium s a l t s . This oxidation of sulphur i s a b i o l o g i c a l one. The inclusion of farmyard manure with the Appendix "v~ -contd-sulphur application i s frequently b e n e f i c i a l as the bacterial content of the manure w i l l produce a more rapid oxidation of the sulphur. Iron sulphate and alum are two amendments frequently used. On hydrolysis of these s a l t s , sulphuric acid i s produced. The hydrogen ion thus formed displaces sodium from the absorbing complex. The reactions are similar to those of sulphur. The hydroxides of iron and aluminum formed are precipitated as c o l l o i d s . These c o l l o i d s on drying are oxidised to inert ' forms. Green manures are of great benefit. In heavy s o i l s the roots tend to break, up the tenacious character of the s o i l , producing a more rapid leaching of the soluble s a l t s . On decomposing much carbon dioxide i s formed. This carbon dioxide In solution, reacts with calcium carbonate to form the soluble bicarbonate. This increase i n the s o l u b i l i t y of calcium w i l l speed up the replacement of sodium i n the exchange complex. The growing of a green manure i n conjunction with an application of some s o i l amendment i s a happy one. I t frequently happens that after the rapid replacement of sodium, following the application of an acidic compound or a soluble calcium s a l t , that the decomposing organic matter w i l l bring s u f f i c i e n t calcium into solution to complete and maintain a calcium saturated exchange complex. The most satisfactory s o i l amendment and the amount to be applied can only be determined by experimental p l o t work. The many publications on a l k a l i reclamation are of value i n pointing out combinations and methods of application. However, as no two s o i l s are exactly a l i k e each a l k a l i s o i l presents an i n d i v i d u a l problem. Hence the f i n a l recommendation must be based on the experience with experimental plots i n the s o i l investigated. - Bibliography -(8) Association of A g r i c u l t u r a l Chemists. Methods of Analysis 1919. (4) Bouyoucos, G. A comparison of the Hydrometer Method and the Pipette Method f o r making mechanical analysis with new directions. Journal American Society of Agronomy 23 No. 4 1930. I 5) Breazeale, J.F. and Mcueorge, W.T. Sodium hydronide rather than sodium carbonate the source of a l k a l i n i t y i n black a l k a l i s o i l s . University of Arizona Technical b u l l e t i n 13. 19 26. (14) Burgess, P.S. and Breazeale, J.F. Methods for determining the replaceable bases either i n the presence or absence of a l k a l i s a l t s . University of Arizona Technical B u l l e t i n 9. 1926. (16) De Sigmond, A.A.J. The c l a s s i f i c a t i o n of a l k a l i and salty s o i l s . International Congress of S o i l Science. Vol. 1 330. 1927. (17) De Sigmond, A.A.J. The Reclamation of A l k a l i Soils i n Hungary. Imperial Bureau of S o i l Science. Technical communication No. 23 Harpenden, Eng. 1932. (1) Department of Agriculture. The S o i l Survey of Glenmore Area. V i c t o r i a , B.C. 1934. (2.) Department of Agriculture. The Climate of B r i t i s h Columbia. V i c t o r i a , B.C. 1932. (15) Di G l e r i a , J . Reclamation Experiment on Hungarian Alkaline Soils 1929. Kiserletugyi E o z l . Vol. 32 252-89, Reported by A.A.J. De Sigmond. The Reclamation of A l k a l i s o i l s i n Hungary. Imperial Bureau of S o i l Science. Technical communication No. 23 Harpenden, Eng. 1932 Bibliography -contd-(11) Gedroiz, K.K. Contribution to the Method of Determining the Zeoletic Bases i n the S o i l . Zhur. Opit. Agron. 19:226-244 1918, Reported by W. P, Kelley and S. M. Brown, Principles governing the reclamation of a l k a l i s o i l s Hilgardia 8 Ho. 5, University of C a l i f o r n i a 1934. (3) Jacks, G. V. S o i l Vegetation and Climate. Imperial Bureau of S o i l Science Technical Communication Ho. 29. Earpenden, Eng. 1934 118) Kelley, W.P. and Arany, A. The chemical effects of gypsum, sulphur, iron sulphate and alum on A l k a l i s o i l . H i l g a r d i a , Vol. 3 No. 14 University of C a l i f o r n i a 1928. (191 Kelley, W.P. and Brown, S.M. Principles.governing the Reclamation of A l k a l i s o i l s , Hilgardia vol. 8 No. 5 19 34. (10) Lang, R.and Muck G. Iodometric Determination of Sodium as Sodium Zinc Uranyl Acetate. Ztschr. Anal. Chem. 93 100 - 102 1933. Reported i n recent developments i n s o i l analysis No. 4 Imperial Bureau of S o i l Science Harpenden, Eng. 1934 (13) Magestad, 0,0. and Burgess, P.S. The use of alcoholic s a l t solutions f o r the determination of replaceable bases i n calcareous s o i l s . University of Arizona. Technical B u l l e t i n 20. 1928. (7) Hoyes, A.A. Qualitative Chemical Analysis 1925. (6) Scott, W.W. Standard Methods of Chemical Analysis. 1927. (9) Steenkamp, J.L. Micro-chemical Analysis of S o i l s . Second Inter-national Congress of S o i l Science 1930. (12) Tj u r i n , I .W. Method of Determination of Exchangeable Calcium and Magnesium i n s o i l s containing alkaline earth carbonates La Pedologie 22: 5-24, 1927, Reported by W.P.Eelley and b,M.Brown. Prin c i p l e s governing the Reclamation of A l k a l i s o i l s . Hilgardia 8 Ho. 5 University of C a l i f o r n i a 1954. 

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