Land and Food Systems, Faculty of
DSpace
UBCV
Trumpour, Maurice Paul Dorland
Master of Science - MSc
University of British Columbia
[No abstract available]
LEh h?. t9t? THE MAINTENANCE OF FERTILITY IN ORCHARD SOILS by Maurice Paul Borland Trumpour. A Thesis submitted i n P a r t i a l F u l f i l m e n t of the Requirements f o r the Degree of MASTER OF SCIENCE IN AGRICULTURE i n the Department of H o r t i c u l t u r e . The U n i v e r s i t y of B r i t i s h Columbia A p r i l , 1940. Table of Contents Iixtrodxict/Xon* • * «• • • • • • • • ••« » • » •«'•••« • • •« • 1 7 Review of l i t e r a t u r e - . . , , . . 2 Time and place of the work 7 Ma t e r i a l s and Methods . .8-16 The Orchard 8 The F e r t i l i z e r Programme 8 Map of Orchard . 10 S o i l A n a l y s i s . 11 Sampling........................... t 11 Mechanical a n a l y s i s of the s o i l . . . . . 11 Chemical a n a l y s i s of the s o i l s o l u t i o n . . . . . 11 Carbohydrate/Nitrogen r e l a t i o n s h i p i n current season shoot ^ x* o tlx • • • «« «••• » * • • • » ILS Tree-growth measurements . . 15 ^^esults.............«.....•.......'........16 *™ 31 S o i l A n a l y s i s 16 Carbohydrate/Nitrogen r e l a t i o n s h i p i n current season shoot growth. 27 Tree-growth measurements 28 DMcussion of Results........................32-37 Cone Xus x ons «•••«• •«••»••••••••••••••••••• 3*7 Sixinm^ 3? y »••••••••••••«...•••••••••••••••••••••• 38 L i t e r a t u r e c i t e d . . . 40 Appendix A 42 Gild XX 33 • « • • • • • » • »••••«•«•» • * • »«eee«»««*««e« 4:3 1, THE MAINTENANCE OF FERTILITY IN ORCHARD SOILS INTRODUCTION The maintenance of orchard s o i l s a t a state of f e r t i l i t y s a t i s f a c t o r y f o r optimum tree growth and f r u i t production c o n s t i t u t e s one of the major problems i n f r u i t growing. I t i s a problem that i s not confined to any par-t i c u l a r s e c t i o n , but one that i s encountered i n f r u i t growing areas the world over. A p o s s i b l e reason f o r t h i s i s expressed i n the f o l l o w i n g words of Hoy (13): 15 I t nasi long been estab-l i s h e d that there are no s o i l s that are i n e x h a u s t i b l e , that can maintain high y i e l d s i n d e f i n i t e l y without the a d d i t i o n from time to time of those constituents•taken out by the p l a n t . Of a l l the elements taken from the s o i l by the p l a n t , three of them--nitrogen* phosphoric a c i d , and potash--are the ones g e n e r a l l y supplied i n the form of fertilizer» I t i s known that l a r g e r q u a n t i t i e s of these m a t e r i a l s are removed from the s o i l annually i n a crop of f r u i t and increased tr e e -growth; therefore we can assume that e v e n t u a l l y a poin t w i l l be reached when the growth w i l l come to a s t a n d s t i l l and y i e l d s w i l l decrease i f the supply of plant-food i s not maintained. M In other words, there has been no su c c e s s f u l determination as to how w e l l the s o i l n u t r i e n t s can be kept at a p r o p e r l y balanced l e v e l . In the c o a s t a l area of B r i t i s h Columbia, and p a r t i -c u l a r l y on the l i g h t e r upland s o i l s , t h i s problem of orchard s o i l management i s accentuated by the large amount of p r e c i - . p i t a t i o n during the f a l l and winter months. For, i n a d d i t i o n 2, to the removal of n u t r i e n t s from the s o i l by plant growth, there i s a l o s s brought about by l e a c h i n g . This paper deals w i t h an orchard subjected to the conditions generalized i n the preceding paragraph. Through unavoidable circumstances, t h i s orchard had been neglected to a s t a t e where i t ceased to be productive and i t became d e s i r a b l e to b r i n g i t back to a state where the trees would resume t h e i r vigour and bear s a t i s f a c t o r y crops. At the same time, there has, i n the c o a s t a l area of B r i t i s h Columbia, been the need of a greater knowledge of the use of f e r t i -l i z e r s . Therefore, i t seemed advisable to c a r r y out a f e r -t i l i z e r program on t h i s orchard i n the hope that i t would be r e v i t a l i z e d and that the r e s u l t s obtained might be used to supplement the present, knowledge of f e r t i l i z e r s i n r e l a t i o n to the conditions that e x i s t e d . / Review of L i t e r a t u r e From the numerous reports which p r e v a i l i n a g r i -c u l t u r a l l i t e r a t u r e , i t i s evident that f e r t i l i z e r s are gen-e r a l l y regarded as a favourable f a c t o r i n the maintaining of orchard s o i l f e r t i l i t y . Unfortunately, r e s u l t s from f e r t i -l i z e r p r o j e c t s have not always been as conclusive as could be d e s i r e d . Chandler (10), a f t e r reviewing the l i t e r a t u r e of numerous f e r t i l i z e r t r i a l s w i t h f r u i t t r e e s , seemed to f i n d that peach and plum trees show more response to f e r t i l i z e r s than do apple and pear t r e e s . Moreover, where f i e l d crops may show marked response to a p p l i c a t i o n s of some of the elements, there i s no response to any element i n the case of some f r u i t s , and response only to nitrogen i n the case of others <. Perhaps much of the doubt that has a r i s e n i s due to the- negative r e s u l t s so often obtained from a p p l i c a t i o n s of phosphorous and potash. In the case of phosphorous, Smock and Gourley (25) found no d i r e c t response to a p p l i c a t i o n s of t h i s element. They state that i t i s w e l l e s t a b l i s h e d that phosphorous a p p l i e d to a s o i l i n a more or l e s s a v a i l a b l e form i s q u i c k l y " f i x e d " . This degree of f i x a t i o n depends upon the s o i l r e a c t i o n , amounts of aluminum and i r o n oxides present, the amount of calcium and magnesium, and the content of c o l l o i d a l m a t e r i a l . There are c e r t a i n chemical and b i o l o -g i c a l processes which can make a p o r t i o n of t h i s f i x e d phos-phorous a v a i l a b l e . Proebsting (23 )• a s serts that t h i s f i x a t i o n of phosphorous occurs so r a p i d l y that i t never reaches the r o o t s . He has a l s o shown (22) that concentrations of l e s s than 0.5 parts per m i l l i o n of phosphate ion have proved ade-quate f o r normal f u n c t i o n i n g of trees when t h i s concentration i s maintained i n the s o i l s o l u t i o n . Thus there i s l i t t l e wonder, that, while phosphorous has been long e s t a b l i s h e d as an e s s e n t i a l element i n p l a n t growth, Smock and Gourley (25), Proebsting (23), P o t t e r (20), Brown (4), and others could not get response s u f f i c i e n t to warrant the trouble and expense of . phosphorous a p p l i c a t i o n s . Recently» however, there appeared i n the 1939 Northwest F e r t i l i z e r Report (18) an i n t e r e s t i n g point w i t h regard to phosphorous. According to t h i s report 4c there have "been instances where nitrogen alone or phosphorous alone have 'not produced d e s i r a b l e responses while a combina-t i o n of these two elements has. I t would appear that phos-phorous i s the l i m i t i n g f a c t o r but an a p p l i c a t i o n of t h i s element must be accompanied by n i t r o g e n . Potash, too, according to Chandler, J r . (8) i s subject to f i x a t i o n . He found t h i s potash f i x i n g propor-t i o n a l to the c o l l o i d a l content of the s o i l and that sandy s o i l s , of course, w i l l e x h i b i t t h i s l e a s t . The water-soluble f r a c t i o n of a s o i l r a r e l y exceeds 10 parts per m i l l i o n of potassium. In another paper (9) he reports the r e s u l t s of a 6-year period using potassium c a r r y i n g f e r t i l i z e r s . There was no c o n s i s t e n t e f f e c t upon the growth or y i e l d of e i t h e r apple or peach t r e e s . In f a c t , orchard l o c a t i o n and p r e v a i l -ing weather conditions have had a greater e f f e c t upon the performance of the t r e e s . Proebsting (23) remarks that pota-ssium has benefited trees i n more cases than have phosphates. In at l e a s t three experiments i n America, potassium has given response; i n Europe i t i s f r e q u e n t l y b e n e f i c i a l ; but i n C a l i f o r n i a the response to potassium has been u s u a l l y n e g l i b l e . Wilcox (29) has f a i l e d to get s a t i s f a c t o r y r e s -ponse to potash f e r t i l i z e r s i n the Okanagan V a l l e y . However, under h i s conditions the s o i l supply of ava.ilable potassium has been found to be very abundant. The most s t r i k i n g responses to f e r t i l i z e r s on f r u i t trees have been observed i n those cases where ni t r o g e n has been one of the constituents a p p l i e d . Thus, when Overholser and C]a ypool (19) conducted extensive f e r t i l i z e r t r i a l s w ith pear trees they found that the greatest response i n terminal growth, trunk circumference increase, more, heal-thy leaves, and weight and s i z e of f r u i t was noticed i n trees r e c e i v i n g nitrogen i n the f e r t i l i z e r , e i t h e r alone or i n combination. The only manner i n which nitrogen appeared to produce a l e s s favourable response than phosphorous and potash was i n the firmness of f r u i t . This does not n e c e s s a r i l y mean, they s t r e s s , that nitrogen produced undesirable f r u i t . A summing-up of the f i n d i n g s i n the 1939 Report of the Northwest F e r t i l i z e r Conference (18) shows that n i t r o g e n , on the whole, has given the best r e s u l t s . However, as noted above, there have been those instances where nitrogen has been b e n e f i c i a l only when accompanied by phosphorous. Proebsting (21) derived h i s best r e s u l t s from the use of nitrogen i n respect w i t h per cent set of f r u i t and y i e l d . Burke and Morris (6) claim that nitrogen stimulates tree growth more than e i t h e r phosphorous and potassium and Brown (4) states that the only commercial f e r t i l i z e r from which an economic response was secured was one high i n n i t r o g e n . A p p l i c a t i o n s containing phosphorous and potassium had not m a t e r i a l l y influenced e i t h e r y i e l d s or keeping q u a l i t i e s . Since, of the three common ele m e n t s — n i t r o g e n , phos-phorous , and potassium—the nitrogen has been found to give the most d i r e c t responses, then i t s e f f e c t should be r e f l e c t e d i n the carbohydrate/nitrogen r e l a t i o n s h i p i n the respective tree t i s s u e s . Ever since Kraus and K r a y b i l l (14) published t h e i r paper on the carbohydrate/nitrogen r e l a t i o n s h i p i n tomato p l a n t s , there have "been many attempts to use such a r e l a t i o n -ship to determine the c o n d i t i o n of f r u i t t r ees. Lagasse (15) concluded from the r e s u l t s of h i s analyses on m a t e r i a l obtain-ed -under a c t u a l f i e l d conditions that both carbohydrate/nitro-gen and starch/nitrogen r e l a t i o n s h i p s might be used as an a i d toward i n t e r p r e t i n g response of apple trees to v a r i e d environ-mental c o n d i t i o n s . Thomas (27) expresses a s i m i l a r opinion. Lagasse (15) found that i n non-bearing spurs on p l o t s r e c e i v -ing only phosphorous and potassium there was a r a t i o of 42.29; on p l o t s r e c e i v i n g n i t r o g e n , phosphorous and potassium or nitrogen alone a r a t i o of 28.56; and on p l o t s r e c e i v i n g t r i p l e the amount of nitrogen a r a t i o of 20.12; while i n bearing spurs on corresponding p l o t s there were the respective r a t i o s of 21.52, 15.05 and 11.27. The narrowing of the r a t i o i s due i n each case to more nitrogen as the carbohydrate l e v e l remained quite constant. A l s o , since nitrogen has shown the most s t r i k i n g responses i n f r u i t trees and since i t a f f e c t s the carbohy-drate/nitrogen r e l a t i o n s h i p , nitrogen may give responses i n accordance w i t h the time of year i t i s a p p l i e d . H a r r i s ( l l ) has shown that under B r i t i s h Columbia coast c o n d i t i o n s , the common plant f o o d s — n i t r a t e s , calcium, potassium, sulphates, e t c . - - f o l l o w a d e f i n i t e seasonal trend. They are at a m i n i -mum i n March, r i s e sharply to a maximum i n May, d e c l i n e to a near minimum i n J u l y , r i s e again to almost the maximum i n September, and f i n a l l y d e c l i n e to the minimum i n November, at which l e v e l they remain during the winter months.. Therefore, H a r r i s maintains that i n an average good s o i l good response should he obtailed from an a p p l i c a t i o n of r e a d i l y a v a i l a b l e nitrogen i n March and i n J u l y . Good root response would be obtained w i t h f a l l f e r t i l i z i n g but there would be no advan-tage i n t h i s . Nicholson and Pantin (17) d i s c r e d i t f a l l f e r -t i l i z i n g because they c l a i m that the n i t r a t e s w i l l be l o s t by l e a c h i n g . Marsh (16) shows that f a l l f e r t i l i z i n g w ith ammo-nium sulphate has r e s u l t e d i n an e a r l i e r m o b i l i z a t i o n of nitrogen i n the f o l l o w i n g s p r i n g , whereas Weinberger and C u l l i n a n concluded that there was no s i g n i f i c a n t advantage gained by the f a l l a p p l i c a t i o n except p o s s i b l y i n the f i r s t year. In the Okanagan, the w r i t e r has observed considerable f a l l f e r t i l i z i n g w i t h n i t r o g e n . I t would seem that the time of f e r t i l i z i n g w i t h nitrogen i s a problem dependent more of l o c a l i n f l u e n c e s . Time and Place of the Work The f i e l d work was s t a r t e d i n the spring of 1935 by Bans (3) on the two n o r t h e r l y sections of the orchard at the U n i v e r s i t y of B r i t i s h Columbia, Vancouver. From that time, i t was continued by the author. A l l chemical analyses, were c a r r i e d out i n the P l a n t N u t r i t i o n Laboratory of the Department of H o r t i c u l t u r e of the U n i v e r s i t y of B r i t i s h Columbia ° .MATERIALS AHD METHODS The Orchard The part of the orchard used f o r t h i s work consists of two sections separated by a stone w a l l . They have a south-westerly slope, and, f o r convenience, they are designated Section A and Section B. The surface s o i l i s extremely l i g h t and open c o n s i s t i n g of gr a v e l and sand interspersed with boulders of varying s i z e s . The average depth of t h i s l a y e r i s two and one-half f e e t . Beneath t h i s i s a l a y e r of "hard-pan" of approximately the euue depth. The trees were o r i g i n a l l y planted at distances of 16 by 20 f e e t , but, i n 1936, every other tree was removed so they now are 32 by 40 f e e t apart. According to Bans report (3) t h i s part of the or-chard was planted i n 1918 to serve as a temporary orchard. C a r e f u l a t t e n t i o n was given f o r the f i r s t f i v e years and growth was s a t i s f a c t o r y . A f t e r t h i s , i r r i g a t i o n and c u l t i -v a t i o n were discontinued and a clover sod was e s t a b l i s h e d f o r three years, followed by clean c u l t i v a t i o n f o r another two years. Up to 1935, l i t t l e a t t e n t i o n , apart from occasional spraying, has been given. Since then the orchard has been clean c u l t i v a t e d annually. The F e r t i l i z e r Programme F e r t i l i z e r s were a p p l i e d at approximately the sa.me times i n 1935, 1936, and 1937 and at the same rates per p l o t . 9. A map of the orchard showing the p l o t arrangement i s included on page 10. Each s e c t i o n i s marked off into 4 p l o t s w i t h s i n g l e b u f f e r rows of trees separating each p l o t . Section A was div i d e d into 4 f e r t i l i z e r p l o t s A l , A2," A3, and A4 and into 2 check p l o t s A61 and AC2. Nitrogen was applied to P l o t A l around the end of A p r i l a t the rate of 800 pounds per acre of 6-10-10; to P l o t A2 i n late May at the rate of 250 pounds per acre of ammonium sulphate; to P l o t A3 i n J u l y at the rate of 250 pounds per acre of ammonium s u l -phate; and to P l o t A4 i n September at the rate of 250 pounds per acre of ammonium sulphate. Phosphorous and potassium were ap p l i e d to P l o t A l as f o r n i t r o g e n above; and to P l o t s A2, A3, and A4 around the end of A p r i l at the rate of 800 pounds per acre of 0-12-10. These 4 p l o t s also received 2 tons of lime toward the end of September i n 1935. Section B was l i k e w i s e d i v i d e d into 4 f e r t i l i z e r p l o t s B l , B2, B3, ana B4 w i t h corresponding treatments, but only one check p l o t BC3. Thus, i t i s seen that nitrogen was a p p l i e d a t four d i f f e r e n t times of the year,. namely, around the end of A p r i l , l a t e May, the middle of J u l y , and the middle of September to two d i s t i n c t s e r i e s of p l o t s and that a basic a p p l i c a t i o n of phosphorous and potassium was given to a l l the p l o t s about the end of A p r i l f o r each of three years. Lime was a p p l i e d to one complete s e r i e s s h o r t l y a f t e r the work was s t a r t e d . FERTILIZING PLAN of ORCHARD SECT/ON A - //W SECT/ON B - unlived * X X X / X ^3 X X X X X # 9 • • • • • X X X X X X Act x X x /4Z» x A' 4*2 X BC3 <& X ® ® X © X ® X X X X X © X X X X X X X • m X ® • • X X * c • ® X X ® €> X to X X X X X © X X. X > ® X. X X X X X X X X X ® X ® ® ® 9 9 • • • • X X X X ® ® 1 X x X X X X X X ® X © 33 » X ® ® X 52 @ ® ® € x /• © 6/ x ® S ® ® # « 4 a LEGEND • Soil Sample positions * Tree pas(l<Qns © Trees measured for growth and sannpled for C/N .O 11. S o i l A n a l y s i s In order to f o l l o w the trend of the s o i l n u t r i e n t s and to determine to what extent the s o i l was enriched by the a p p l i c a t i o n of the f e r t i l i z e r s , a comprehensive s e r i e s of s o i l samples was obtained and analyzed.. 1. Sampling. S o i l samples were taken twice each year i n 1935, 1936, and 1937, once j u s t before the e a r l y spring f e r t i l i z e r a p p l i c a t i o n s and once about one month a f t e r the September nitrogen a p p l i c a t i o n . A f i n a l s e r i e s was obtained i n the spring of 1938„ In each p l o t , three samples were taken from holes dug to a depth of 18 inches, one at the top of the slope, one at the middle, and one at the bottom. These p o s i t i o n s are marked on the map on page 10. The three samples of each p l o t were composited, a i r d r i e d , s i f t e d through a No. 10 screen, and stored u n t i l - a n a l y s i s could be made. 2. Mechanical A n a l y s i s of the S o i l . F i ve cubic centimetres of dry s o i l were placed i n a tapered c e n t r i f u g e tube, mixed w i t h water and cen t r i f u g e d . By t h i s procedure, there r e s u l t s a gradation i n s i z e of par-t i c l e from coarse to medium to f i n e sand and to two d i s t i n -guishable l a y e r s of coarse and f i n e s i l t . The amounts of sand a n d ; s i l t were measured and the per cent of sand and of s i l t were estimated. 3. Chemical A n a l y s i s of the S o i l S o l u t i o n . A l l s o i l samples were uniformly wetted w i t h d i s t i l -12. l e d water to approximate a moisture content of 16%. Five days l a t e r the moistened samples were packed into tubes and the s o i l s o l u t i o n was obtained i n accordance w i t h the Burd and Martin water displacement system (5). This method has been us'ed e x t e n s i v e l y by R u s s e l l of Rothamstead, Proebsting (23), and Atkinson (2). The r e s u l t i n g displaced s o i l s o l t u i o n was tested as f o l l o w s : (a) Total A v a i l a b l e Nutrients as in d i c a t e d by elec-t r i c a l r e s i s t a n c e . This was measured on a poten-tiometer used as a Wheatstone Bridge. (b) S o i l Reaction (pH). This was determined c o l o u r i -m e t r i c a l l y s.s soon as displacement was complete. Some samples were al s o checked w i t h a Beckman pH Meter. (c) N i t r a t e Nitrogen (NCfo) was determined by the A.O.A.C. phenoldisulphonic a c i d method ( l ) • (d) Phosphates (T?0A ) were determined by an adapta-t i o n of the Truog method (28) . A s u i t a b l e a l i -quot of the displaced s o l u t i o n was d i l u t e d to 95 ml., treated w i t h 5 ml. of ammonium molybdate s o l u t i o n and 2 drops of f r e s h l y prepared stannous c h l o r i d e s o l u t i o n . A f t e r 10 minutes, the blue colour that develops was compared w i t h s i m i l a r l y treated standards. (e) Potassium (K)» Unfortunately, the method f i r s t adopted f a i l e d to produce c l e a r l y defined r e -s u l t s and the information w i t h regard to the 13 o potassium content i s not comparable. The method. •• f i n a l l y used was that devised by Cameron and F a i l y e r (7)„ (f) Calcium (Ca). The Richard and Wells method (24) was used f o r calcium determination. (g) Sulphates {SOa) were determined by the Richard and Wells method (24) f o r sulphates. (h) Lesser Constituents. These include magnesium, n i t r i t e nitrogen, ammonia, manganese, and chlo-r i d e s . They are of no l e s s value than the f o r e -going i n s o f a r as the plant's welfare i s concerned, but i n t h i s p a r t i c u l a r work t h e i r importance i s not so pronounced. Portions of the di s p l a c e d s o l u t i o n were analyzed by the respective Spurway methods (26). Carbohydrate/Nitrogen R e l a t i o n s h i p i n Current Season Shoot Growth 1. Sampling. For t h i s phase of the work, the samples were taken from the same trees marked f o r the tree growth measurements (see map on page 10). The date of sampling was June 15, 1938. About 175 to 200 grams f r e s h weight per p l o t of current season shoot growth were removed, weighed a c c u r a t e l y , d r i e d , and stored i n glass j a r s . Later t h i s m a t e r i a l was ground up to 60-mesh or f i n e r and f u r t h e r d r i e d i n an oven at 95 C u n t i l a constant weight was reached. 14. 2. Moisture Content. This was computed to provide a possible a i d i n the i n t e r p r e t a t i o n of r e s u l t s . 5. Total Carbohydrates. Some 15 grams of the ground-up dried m a t e r i a l were weighed a c c u r a t e l y and extracted overnight w i t h 200 ml. of 95% a l c o h o l . The f o l l o w i n g morning t h i s a l c o h o l was decanted o f f . The residue was tr a n s f e r r e d to a Soxhlet apparatus and e x t r a c t -ed f o r 16 hours w i t h another 200 ml, of a l c o h o l . The two l o t s of a l c o h o l were then combined and allowed to evaporate almost to dryness. 300 ml. of water were added and allowed to eva-porate u n t i l a l l the a l c o h o l had escaped. On co o l i n g , the s o l u t i o n was made up to a volume of 200 ml. and designated S o l u t i o n A. 100 ml. of S o l u t i o n A were almost n e u t r a l i z e d w i t h U/lG HaOH. Basic lead acetate was added u n t i l no f u r t h e r p r e c i p i t a t e r e s u l t e d . A f t e r standing 10 minutes, t h i s s o l u -t i o n was treated w i t h 12-18 ml. of a saturated sodium a c i d phosphate s o l u t i o n to remove excess lead, made up to 200 ml. and f i l t e r e d . F i l t r a t e was designated S o l u t i o n B. (a) Reducing Sugars• S o l u t i o n B was t i t r a t e d against Fehling's s o l u t i o n according to the Lane and Eynon method. (b) Total Sugars. 100 ml. of S o l u t i o n B were treated w i t h 10 gm. of c i t r i c acid, and b o i l e d f o r 15 min-utes . A f t e r c o o l i n g , the s o l u t i o n was neutra-l i z e d w i t h 40$ NaOH and made up to 150 ml. This was t i t r a t e d as f o r reducing sugars. * (c) Total Hydrolyzable Polysaccharides. The residue from the Soxhlet e x t r a c t i o n was transferred to a f l a s k containing 200 ml. of water and 20 ml. concentrated HC1 (S.G. 1.125) and ref l u x e d f o r 2\ hours. A f t e r c o o l i n g , the s o l u t i o n was neutra-l i z e d w i t h c a u s t i c soda, d i l u t e d to 250 ml. and f i l t e r e d . The f i l t r a t e was t i t r a t e d according to the Lane and Eynon method. The amount of glucose present m u l t i p l i e d by 0.9 gave the weight of st a r c h . 4. Total Nitrogen. A q u a l i t a t i v e t e s t f o r n i t r a t e s was negative. For the t o t a l n i t r o g e n , then, 2 gm. of the d r i e d m a t e r i a l were digested i n sulphuric a c i d and the ammonia was d i s t i l l e d over i n accordance w i t h the K j e l d a h l method i n the A.O.A.C, ( l ) . Tree-Growth Measurements Of p o s s i b l e ways of recording tree-growth increases due to various treatments, both trunk growth and terminal twig growth measurements can be used. Twig growth measurements have been used to a considerable extent, but as Chandler (10) points out, they are tedious and do not express the response of the whole t r e e . In t h i s work, trunk growth measurements were used and obtained i n the l a t e winter or e a r l y spring of the years 1935, 1936, 1937, 1938, 1939, and 1940. Trees i n each p l o t were chosen at random and t h e i r p o s i t i o n s are shown 16. on the map on page 10. Each tree was marked with three white hands of-paint as i n d i c a t e d i n f i g u r e 1. The circumference of each mark was measured i n inches w i t h a s t e e l tape. RESULTS S o i l A n a l y s i s 1. Mechanical A n a l y s i s of the S o i l . The r e s u l t s from the mechanical a n a l y s i s are shown i n Table 1. As the d i f f e r e n c e between 100 and the per cent s i l t represents the per cent sand, and, as the increase, i f any, i n per cent s i l t i s of more importance i n t h i s p r o j e c t , only the per cent s i l t values are included i n t h i s t a b l e . P i g . 1. showing genera.l p o s i t i o n s of white bands f o r tree-growth measurements. TABLE I. INCREASE IN THE SOIL SILT FRACTION AS A RESULT OF FERTILIZER TREATMENTS DURING » THE "YEARS 1935 to 1938. P l o t Nitrogen appl i e d 1935 1936 1937 1938 . Apr.. Oct. Apr. Oct. Oct. Apr. AC1 check 30.0 33.3 33.9 30.4 30.0 31,9 28 .6 AC2 che ck 28 .3 29.6 27.4 28.8 28.8 32.0 37.4 A l l a t e Apr. 18.4 23.2 25.9 31.3 40.8 38.5 34.3 A2 l a t e May 13 ».3 19.1 14.9 22.9 34.0 34.0 41.9 A3 J u l y 26.0 29 .4 28 .8 30.7 36.0 36 .8 38.9 A4 Sept. 27.3 30.0 28.8 31.8 35.1 37.6 39.9 BC3 check 30 .0 31.2 29.4 28.5: 32,0 31.6 37.7 B l l a t e Apr. 2-7.61 33«9 32.7 32.0 30.1 38 .2 32.5 B2 l a t e May 24.3 21.5 26.3 27.2 29,6 35.7 32.5 B3 J u l y 23.2 30.7 32.6 31.3 34.6 39.7 39 .3 B4 Sept. 19.. 5 28.8 29 .4 26.7 31.8 35.1 36.8 In the foregoing table on the r e s u l t s of the mechanical a n a l y s i s of the s o i l , the check p l o t s have approx-imately the same amount of s i l t when the experiment was s t a r t -ed i n 1935. These amounts remain constant throughout the and experiment i n P l o t A C l ^ u n t i l the 1958 samples i n P l o t s AC2 and BC3, when very marked increases are n o t i c e d , In the remaining f e r t i l i z e d p l o t s there are d e f i n i t e increases i n the amounts of s i l t from March 1935 to March 1938. The trends i n P l o t s A l and B l vary during t h i s period so that there are considerably l e s s e r amounts of s i l t i n A p r i l 1938 than i n the preceding f a l l , and, f o r P l o t A l i n the spring of the year before. There are no consistent c o r r e l a t i o n s with 18. the d i f f e r e n t s o i l treatments. In f a c t , P l o t A2 had the l e a s t s i l t , of the 1935 samples and the most of the 1938 sam-p l e s , whereas P l o t B l had the most s i l t (except the check p l o t s ) of the 1935 samples and the l e a s t of the 1938 samples The l a r g e s t increases, on the whole, are found i n . the p l o t s i n Section A which had the lime a p p l i c a t i o n i n September 1935. This i s shown i n Table 11. TABLE I I . AVERAGE INCREASE IN THE SOIL SILT FRACTION IN THE LIMED AND UNLIMED SECTIONS, FROM 1935 to 1938. 1935 1938 In-crease % In-crease Average f o r limed p l o t s Average f o r unlimed p l o t s 21»2 23.6 38 • 7 3 5 o 2 .17.5 11.6 82.5 44.4 2. Chemical A n a l y s i s of the S o i l S o l u t i o n . (a.) Total A v a i l a b l e Nutrients as i n d i c a t e d by e l e c -t r i c a l r e s i s t a n c e . The values obtained are expressed i n ohms and are found i n Table I I I . When the r e s i s -tance of the s o l u t i o n i s high, there i s l e s s e l e c t r i c a l c o n d u c t i v i t y and hence that s o l u t i o n has r e l a t i v e l y smaller amounts of n u t r i e n t s f o r p l a n t use. The s o i l s o l u t i o n s of the treated p l o t s , without exception, have the l e a s t n u t r i e n t s , as i n d i c a t e d by the greater e l e c t r i c a l r e s i s -19. tance, i n the spring of each year. The check p l o t s AC2 and BC3 also f o l l o w t h i s trend and the remaining check p l o t AC1 shows a s i m i l a r trend except i n the f a l l of 1935 and the spring of 1936. There are l e s s n u t r i e n t s i n the s o i l s o l u t i o n i n the f i r s t samples of 1938 except the check p l o t BC3. TABLE I I I . THE EFFECT OF FERTILIZER TREATMENTS ON TOTAL NUTRIENTS AS INDICATED BY ELECTRI-CAL RESISTANCE OF SOIL SOLUTION (ohms) P l o t Nitrogen a p p l i e d 1935 . 1936 1937 1938 Apr. Oct. Apr. Oct. AP r- Oct. Axsr. AC1 check 1191 854 816 461 775 406 612 AC2 check 840 373 464 427 960 449 694 A l l a t e Apr. 1159 338 779 275. 691 336 747 A2 l a t e May 944 203 701 360 661 301 514 A3 J u l y 916 214 701 181: 797 219: 410 A4 Sept. 1025 205 356 176 797 155 547 BC3 check 667 374 816 797 951 878 1061 B l l a t e Apr. 1029 215 816 323 710 483 736 B2 l a t e May 1000 223 701 264 883 301 505 B3 J u l y 1252 262 743 169 685 264 679 B4 Sept. 766 184 836 205 946 239 520 (b) S o i l Reaction (pH) The s o i l r eactions or hydrogen-ion concentrations of the s o i l s o l u t i o n s are l i s t e d i n Table IV. The i n i t i a l r e a c t i o n s , as shown by t h i s t a b l e , are 20. remarkably uniform and d e f i n i t e l y a c i d . Generally, the s o i l i s more a c i d i n the f a l l season, although there are not the dif f e r e n c e s i n the 1935 spring and f a l l p l o t s i n Section A that there are i n Section B. There are very s l i g h t increases in' pH from the spring of 1935 to the spring of 1938 i n Section A, while there are no changes i n Section B. TABLE IV. THE EFFECT OF FERTILIZER TREATMENTS ON THE REACTION OF THE SOIL SOLUTION (pH)... P l o t Nitrogen a p p l i e d 1935 1936 1937 1938 Apr. Oct. Apr. Oct. Apr. Oct.' Apr. AC1 check 5.6 5 .6 6.0 5 .8 5.4 5.5 5.8 A02 check 5.6 ' 5.6 6.0 6.0 6.0 5»5 5 .5 A l ; l a t e Apr. 5.6 5.5 5.6 6.1 5.9 5 © 3' 6.0 A2 l a t e May 5.7 5.6 5.8 5 © 9 5.7 p; q A3 J u l y - 5.7 5.6 5 .8 5.9 5.5 5.2 5.6 A4 Sept. 5.8 5.8 5.9 5.5 6 .2 5.1 5.7 BC3 check 5.6 5.5 5.9 5«9 5.5 5 15 5 5.7 B l l a t e Apr. 5.6 5.2 6.0 5.5 5.9 5.5 5.7 B2 l a t e May 5.6 5.3 6.1 5.8 5.9 5.6 5.6 B3 J u l y 5.6 5.2 6.0 5.4 6 .2 . 5.5 5.4 B4 . : Sept. 5.9 5.6 6.0 5.6 5.7 5 .4 5.8 (c) N i t r a t e Nitrogen (NO?,). The r e s u l t s f o r n i t r a t e s are l i s t e d i n Table V. J u s t as there i s a greater t o t a l n u t r i e n t con-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 s of the f a l l p l o t s , so there i s g e n e r a l l y a higher n i t r a t e content i n the f a l l . The 21. lowest n i t r a t e values are found, i n the 1937 spring samples (and they- are appreciably lower than i n 1935) but the time of year i n r e l a t i o n to e a r l i n e s s of season when the samples were obtained may have a bearing on t h i s . An unusually high value i s seen i n the P l o t B l spring sample f o r 1937. Insofar as di f f e r e n c e s due to treatment are con-cerned, the more consistent r e s u l t s are found i n the limed p l o t s of Section A. P l o t A l has the lowest n i t r a t e content, A2 a l i t t l e more, and A3 or A4 d e f i n i t e l y the highest. The Section B p l o t s tend to vary, p a r t i c u l a r l y i n the spring sam-ple s ; but, ge n e r a l l y i n the f a l l samples, P l o t B l which cor-responds to P l o t A l i n treatment, has the l e a s t n i t r a t e n i t r o -gen and P l o t B4, which corresponds to P l o t A4, the highest. TABLE V. THE EFFECT OF FERTILIZER APPLICATIONS AT DIFFERENT TIMES OF THE YEAR ON THE NITRATE CONTENT OF THE SOIL, SOLUTION (p.p.m.) P l o t Nitrogen a p p l i e d 1935 1936 1937 1938 Apr. Oct. Oct. Apr. Oct. Apr. AC1 check 25 51 41 70 10 127 37 AC2 check 24 42 80 161 18 97 37 A l l a t e Apr. 14 20 27 37 .6. 107 28 A2 l a t e May 15 20 27 59 8 147 38 A3 J u l y 20 23 47 450 10 300 60 A4 Sept. 14 24 48 373 10 333 58 BC3 check 28 48 33 93 14 50 22 B l l a t e Apr. 33 20 22 38 68 38 40 B2 l a t e May 37 31 49 81 25 157 27 B3 J u l y 20 14 57 343 6 203 62 B4 Sept. 14 15 80 143 12 147 50 The check p l o t s reveal marked increases i n n i t r a t e i n the f a l l months even though they were not f e r t i l i z e d . N i t r a t e nitrogen i s higher at the end of the pro-j e c t than at the s t a r t . (d) Phosphate (PO^ ) The r e s u l t s from the phosphorous determinations appear i n Table V I . TABLE VI. THE EFFECT OF FERTILIZER APPLICATIONS ON THE PHOSPHOROUS CONTENT OF THE SOIL SOLUTION (p.p.m.) P l o t Nitrogen a p p l i e d 1935 1936 1937 1938 Apr. Oct. Apr. Oct. Apr. Oct. Apr» AC1 check 2.3 2.6 2.0 2.0 2.2 1 , 8 1.8 A02 check 2 e 6 2.4 1.9 1.9 X aS 1 0 8 • 1 . - 5 -. A l : l a t e Apr. 2«3_ 2.3 2.1 2.7 2«2 2.1 1.9 A2 l a t e May 1.8 2.3 2.0 2 o 5 . 2.1 X«o 1.6 A3 J u l y 2«3 2.2 2.0 1.9 2»X- .2.1 1.9 A4 Sept. 2.3 2«3 2 s 3 2.0 2.3 1,8 1.8 BC3 check 2 • i 1.9 1.9 1.9 1.8 2 o 0 1.6 B l l a t e Apr. 1.9 2.2 2.6 2.0 2.2 1.5 1.5 B2 l a t e May 2.0 2.2 2 o *7 2 . 0 2 . 1 X«5 1.6 B3 J u l y 2.0 2.2 2.7 2.0 2«1 1.8 1.5 B4 Sept. 1.2 2.3 2.9 2.0 2 o 2 2.0 1.8 There i s only one outstanding and consistent feature shown by the above table of phosphorous determina-t i o n s . The r e a d i l y a v a i l a b l e phosphorous i n the orchard i s 25. higher a t the s t a r t of the work i n 1935 than i t i s at the end i n 1938 a f t e r three annual a p p l i c a t i o n s of a phosphorous f e r -t i l i z e r . This i s al s o noticed i n the check p l o t s which/ were not treated w i t h t h i s element. (e) Potassium i (K) The potassium r e s u l t s are found i n Table V I I . As noted before (page 12), these r e s u l t s are unfortunately incom-p l e t e , but there are s u f f i c i e n t data f o r presentation. TABU! V I I . THE EFFECT OF FERTILIZER APPLICATIONS ON THE POTASSIUM CONTENT OF THE SOIL SOLUTION (p.p.m.) P l o t Ni trogen a p p l i e d 1935 1937 1938 Apr. i Apr. Oct. Apr. AC1 check 2.6 11 20 11 AC2 check 6.5 9 8 A l l a t e Apr. 5.5 7 14 9 A2 l a t e May 5.0 9 13 . 9 A3 J u l y 3.8 6 22 9 A4 Sept. 3 a 2 7 22 9 BG3 check 6.9 24 12 6 B l l a t e Apr. 3.5 12 15 9 B2 l a t e May 3.4 11 22 14 B3 J u l y 4.2 17 18 6 B4 Sept. 2 © 5 7 23 7 These r e s u l t s i n d i c a t e that the potassium follows the t o t a l n u t r i e n t and n i t r a t e trends, being high i n the f a l l and lower i n the s p r i n g . There are no d e f i n i t e c o r r e l a t i o n s 24. between p l o t s , except, perhaps those i n Section A do not vary-so widely. 'In f a c t , P l o t s A l , A2, A3, and A4 i n October 1937 correspond e x a c t l y i n t h e i r potassium trend to t h e i r n i t r a t e supply. The potassium has d e f i n i t e l y been increased i n the three years of f e r t i l i z i n g as shown by the lower values at the s t a r t and the appreciably higher values at the conclusion. Howeverr the untreated check p l o t s a l s o show s l i g h t increases i n t h i s p e r i o d . (f ) Calcium (Ca) The calcium contents of the s o i l s o l u t i o n s are shown i n Table V I I I . TABLE V I I I . THE EFFECTS OF FERTILIZER APPLICATIONS ON THE CALCIUM. CONTENT OF THE SOIL SOLUTION (p.p.m.) P l o t Nitrogen a p p l i e d 1935 1936 1937 1938 Apr. Oct. Apr.: Oct. Apr. Oct. Apr. AC1 check 21 34 28 50 24 49 19 ACS check 26 34 27 29 22 71 ; 45 A l l a t e Apr. 22 56 24 130 1 - 1 9 75 33 A2 l a t e May 26 75 28 79 29 73 44 A3 J u l y 22 128 37 120 25 135 41 A4 •Sept. 22 72 42 147 19. 202 42 BC3 check 29 33 22 18 28 18 21 B l l a t e Apr. 22 84 25 62 45 52 23 B2 l a t e May 25 79 27 89 27 82 17 B3 J u l y 15 51 31 64 19 53 40 B4 Sept. 26 67 34 100 29 101 18 The r e s u l t s from the calcium determinations are not as d e f i n i t e as could be desired i n that there are numerous increases which do not give smooth trends. The calcium does f o l l o w s i m i l a r trends to those of the n i t r a t e s , but i n l e s s concentrated amounts. There are no large increases i n 1938 over 1935 even i n those p l o t s which, received the lime. The calcium content of the s o i l i s markedly uniform throughout the orchard at the s t a r t ; but, at the end, i t i s s l i g h t l y higher i n Section A than i n Section B. Some of the untreated check p l o t s a l s o show appreciable increases. is). Sulphates. (SQ 4) The r e s u l t s from the sulphate analyses are found i n Table IX. TABLE IX. TEE EFFECT OF FERTILIZER APPLICATIONS ON THE SULPHATE CONTENT OF THE SOIL SOLUTION (p.p.m.) P l o t Nitrogen a p p l i e d 1935 1936 1937 1938 Apr... .Get'. Apr. Oct. Apr. Oct. Apr. AC1 check 10 19 29 . 33 33 10 35 AC2 cheek 15 17 27 39 45 18... 28 A l l a t e Apr. 11 5 21 44 55 . 42 39 A2 l a t e May 9 18 31 44 44 40 64 A3 J u l y 13 25 56 44 38 37 A4 Sept. 13 17 27 ; 88 .• 59 53 32 BC3 check 12 ; 35 23 15 '20 . S i . 10 B l l a t e Apr. 8 17 23 28 20 39 23 B2 l a t e May 7" 8 22 29 26 35 44 B3 : J u l y 7 : 1 7 • 32 25 33 42 27 B4 Sep t . 26 37 28 63 43 55 41 With sulphates, a l s o , there i s noticed a higher, though not so pronounced, l e v e l i n the f a l l months. Two i r r e g u l a r values are to be observed, however, i n the check p l o t s AC1 and AC2 f o r the f a l l of 1937 when the sulphate 26. content i s lower than i n the preceding and succeeding spring months. Up to the f a l l of 1936 there i s a general increase i n the sulphate content, a f t e r which the l e v e l remains unchanged. Accordingly, there are more sulphates i n the s o i l at the conclusion of the f e r t i l i z e r a p p l i c a t i o n s i n A p r i l 1938 than there were at the s t a r t i n 1935. (h) Lesser Constituents. No d e f i n i t e f i g u r e s are presented here. Rather, an i n d i c a t i o n as to whether these constituents are absent or present to a small, medium, or large degree i s as f o l l o w s : -( i ) N i t r i t e Nitrogen (NOp.) - d e f i n i t e l y absent. ( i i ) Ammonia ( N H g ) p r e s e n t to a small degree. The values obtained were not pronounced enough to i n d i c a t e i f there were seasonal trends or f e r -t i l i z e r i n f l u e n c e s , ( i i i ) Magnesium (Mg) - g e n e r a l l y absent i n the spring; but a trace evident i n the f a l l . ( i v ) Manganese (Mh) - the blue s o l u t i o n character-i s t i c of the Spurway te s t (26) was never ob-tai n e d . Rather, a y e l l o w i s h green cloudiness r e s u l t e d which was of approximate density i n a l l the t e s t s . (v) Chlorides (CI) - present to a medium extent. The f a l l samples g e n e r a l l y contained more c h l o r -ides and there was no decrease or increase ev-ident from the s t a r t of the pro j e c t u n t i l the end. 27 Garbohydrate/Nitrogen_Relationship i n Current Season Shoot Growth. The complete a n a l y t i c a l r e s u l t s of t h i s phase of the work are to "be found at the end of the paper under Appendix A. Below, i n Table X, are shown the t o t a l carbohydrates contents t o t a l nitrogen content, each expressed as per cent of the d r i e d t i s s u e , and the r a t i o of these two c o n s t i t u e n t s , as derived from the r e s u l t s i n the Appendix. TABLE X. THE EFFECT OF NITROGEN APPLICA-TIONS AT DIFFERENT TIMES OF THE YEAR ON TOTAL CARBOHYDRATES, TO-TAL NITROGEN, AND C/N RATIO IN CURRENT SEASON SHOOTS, June 15, 1938. P l o t Ni trogen a p p l i e d T o t a l Carbo-hydrates % T o t a l Nitrogen % C/N Ratio A c l cheek : 24.17 1.288 18.7 ACS check 28 .5 1,197 23.8 A l l a t e Apr. 32 .1 1.169 27,4 A2 l a t e May 27.9 1.302 21.4 A3 J u l y 28.1 1.372 20.4 A4 Sept. 33 .8 X o 372 24.6 BC3 check 22.6 X o 323 17.0 B l l a t e Apr• 31.4 1 »218 24.9 B2 .late May 29 .6 1.190 24.8 B3 J u l y 31.5 1.334 23 .6 B4 Sept. 33«1 1.334 24.7 P l o t 4 of each Section has the highest t o t a l carbo-hydrates, P l o t 1 the next highest, although P l o t B3 i s j u s t 28, as high as P l o t B l , and P l o t 2 of each s e c t i o n the lowest. "P l o t s 3 and 4 of each s e c t i o n have r e s p e c t i v e l y the same amounts of nitrogen and these amounts are the highest f o r t h e i r respective p l o t s . In Section A there i s a general increase i n nitrogen from the l a t e A p r i l treated. P l o t A l to the l a t e May treated P l o t A2 to the J u l y and September treated P l o t s A3 and A4. This consistency i s not quite so i n Section B as P l o t B l has more nitrogen than the P l o t B2. The r e s u l t i n g C/N r a t i o s do not d i f f e r to any marked degrees, p a r t i c u l a r l y i n Section B. In f a c t , these values agree w e l l w i t h those of Harvey and Murneek (12). Tree-Growth Measurements The complete records of the growth measurements taken each year are tabulated, i n Tables i and i i of Appendix B a t the end of the paper. The a c t u a l increases made by each measured tree are shown i n Tables i i i and i v of Appendix B. On the f o l l o w i n g two pages are presented g r a p h i c a l l y the aver-age increases made by each f e r t i l i z e d p l o t w i t h reference to the time of year the nitrogen a p p l i c a t i o n s were made. I t must be remembered that Section A i s comprised only of apple trees, while Section B i s comprised of d i f f e r e n t species i n c l u d i n g apple, pear, a p r i c o t , and cherry t r e e s . The greatest annual increases i n Section A were made i n the period from 1936 to 1937. In no l a t e r periods were the increases so great. However, i n Section B, while there were no great increases up to 1936, the increases were continued so that there are j u s t as large increases i n 1937, 1938, and 1939 as there are i n 1936. 9.01 T aoh 7oH •5 1937 /93Q /?3? WO Year of measurement Fig Z. Graph showing average frank yrowfh increases for each P/of iri Section /4 /<?36 /<?37 iqss mq mo Year of measurement-fig. 3. Graph showing average frunk growth increases -for each Plot in Section 3. 32. DISCUSSION OF RESULTS The Mechanical A n a l y s i s of the S o i l One of the f i r s t points evident i n t h i s work i s the increase i n fineness of the s o i l p a r t i c l e s . This may be p a r t l y due to the e f f e c t s of the clean c u l t i v a t i o n the or-chard received i n preceding years so that more s o i l p a r t i c l e s have been exposed to the weather with a consequent breaking down to release more elements f o r plant use. But, the lime must have been a f a c t o r i n t h i s general increase i n fineness, f o r while there are very appreciable increases i n a l l f e r t i -l i z e d p l o t s , there are much greater increases i n the limed p l o t s . The A v a i l a b l e Nutrients in. the S o i l There has, as a r e s u l t of the a p p l i c a t i o n s of the f e r t i l i z e r s , been a general increase i n plant n u t r i e n t s . This i s d e f i n i t e l y seen i n the r e s u l t s f o r t o t a l n u t r i e n t s , n i t r a t e s , potassium, calcium, and sulphates when spring sam-ples are compared. Phosphorous i s the only element that has not shown an increase, but rather a decrease, which may be a t t r i b u t e d to f i x a t i o n processes i n the s o i l as stressed by Smock and Gourley (25) and by Proebsting (23). Or, t h i s decrease may be that, due to the increased n i t r o g e n , the trees have, been stimulated to such an extent that they absorb phos-phorous i n l a r g e r q u a n t i t i e s than before. This l a s t supposi-t i o n t i e s i n wi t h the evidence produced i n the 1939 Report of the Northwest F e r t i l i z e r Conference (18) that a p p l i c a t i o n s of 33. phosphorous have been found to give desired responses i n cer-t a i n instances only with the a p p l i c a t i o n of nitrogen a t the same time. Leaching i s evident from the r e s u l t s of the s o i l a n a l y s i s . In the l i g h t of the experience of other workers and from the conditions of heavy winter r a i n s and l i g h t open s o i l encountered i n t h i s l o c a l i t y , i t i s not s u r p r i s i n g that leaching should be a f a c t o r of s i g n i f i c a n t proportions. For example, i n A p r i l 1938, there i s as much calcium i n P l o t A2 as i n A4, yet i n the p r e c e d i n g - f a l l there i s only one-third as much. In May 1936, there i s as much calcium i n P l o t A4 as i n A3, yet i n the preceding f a l l there i s only t h r e e - f i f t h s as much. Numerous s i m i l a r losses of n u t r i e n t s other than of calcium can be found. In other words, while the general l e v e l of n u t r i e n t s has been increased by the f e r t i l i z e r treatments, there i s no reason why t h i s l e v e l should not f a l l o f f r a p i d l y now that the f e r t i l i z e r a p p l i c a t i o n s have been discontinued. In order to prolong the e f f e c t of the f e r t i l i z e r s , then, some a d d i t i o n a l p r a c t i c e must be followed and t h i s could best be done by the inauguration of an annual winter cover crop sys-tem which would hold these n u t r i e n t s through the danger per-iod when f a l l and winter r a i n s p r e v a i l . I t i s quite l i k e l y that as the concentration of the n u t r i e n t s was so low at the s t a r t of the experiments that the establishment then of a cover crop system would have been f u t i l e , but now, w i t h the increased n u t r i e n t s , i t seems e s s e n t i a l that there i s the p l a n t i n g of a cover crop. A cover crop would have a second e f f e c t i n increas-ing the organic matter of the s o i l , which would, conserve moisture f o r the bene f i t of the trees during the summer months when the water supply i s often p r e c a r i o u s l y low. I t i s i n t e r e s t i n g to note that there are, i r r e s p e c -t i v e of treatments, seasonal trends of t h e s o i l n u t r i e n t s which are i n close agreement w i t h H a r r i s ' n u t r i e n t curve (11). The untreated check p l o t s show them quite d e f i n i t e l y and the treated p l o t s much more d e f i n i t e l y . Of the n u t r i e n t s tested, phosphorous does not appear to f o l l o w any trend but t h i s i s most l i k e l y due to the low concentrations of t h i s element that p r e v a i l . The spr i n g samples were taken so soon a f t e r s o i l a c t i v i t y had s t a r t e d and before the May maximum that they n a t u r a l l y i n d i c a t e low concentrations of a l l n u t r i e n t s . The f a l l samples were taken not long a f t e r the September peak and so show a good supply of r e a d i l y a v a i l a b l e n u t r i e n t s . The f a l l samples, too, have had a f u l l e r b e n e f i t of the f e r t i l i z e r a p p l i c a t i o n s f o r the respective year and i t i s quite p o s s i b l e the September maximum was higher than the May maximum. The E f f e c t of Nitrogen A p p l i c a t i o n s on the C/N R e l a t i o n s h i p . The f i r s t e f f e c t of the nitrogen f e r t i l i z e r s would be to increase the nitrogen content of the tree t i s s u e s . In the f a l l of 1937, the s o i l i n the J u l y and September nitrogen treated p l o t s of Section A contained more nitrogen than those p l o t s treated i n the spr i n g . Somewhat s i m i l a r but l e s s d e f i -n i t e r e s u l t s are seen i n Section B. Now, i n the f o l l o w i n g s p r i n g , these same p l o t s have correspondingly p r o p o r t i o n a l amounts of n i t r a t e nitrogen and the shoots of the trees of 35. the respective treatments contain p a r a l l e l increases i n t o t a l n i trogen. I t would seem that nitrogen a p p l i e d i n the f a l l r e s u l t s i n increased nitrogen i n the tree t i s s u e and t h i s may-have "been increased even more but f o r the f a c t that leaching probably caused a l o s s of n i t r a t e s before they could be e n t i r e -l y absorbed by the t r e e . In other words„ a cover crop again seems to be an important f a c t o r i n the l i g h t of G/E evidence. Because the nitrogen content of the twigs of the J u l y and September nitrogen treated p l o t s i s greater than of those i n the spring nitrogen treated p l o t s , then those trees of the former should have, according to Chandler (10), l a r g e r , more healthy f o l i a g e , more surface f o r photosynthetic a c t i v i -t y , and hence more t o t a l carbohydrates. I f , therefore, the more healthy trees have more of these constituents--carbohy-drates and n i t r o g e n - - i t i s reasonable to expect greater growth increases. However, i n Section A, while there are not s i g n i f i c a n t d i f f e r e n c e s between p l o t s w i t h regard to tree growth, the trees w i t h l e s s nitrogen i n the shoots show i n d i -cations of making b e t t e r growth than those w i t h more nitr o g e n . A s i m i l a r r e s u l t occurs i n Section B. A c t u a l l y , the trees i n the September nitrogen treated p l o t s have the most carbohy-drates and most nitrogen but have made the poorest growth; whereas the trees i n the e a r l y spring treated p l o t s have l e s s carbohydrates and nitro g e n , but have made the greatest growth. However, since both the growth does not p a r a l l e l the increase of nit r o g e n i n the shoots and the C/K values obtained i n t h i s paper are so very s i m i l a r , and, as pointed out before. they agree so w e l l with the f i n d i n g s of Harvey and Murneek (12) f o r normal trees under optimum conditions, then i t must he concluded that the trees i n t h i s experiment were, at the conclusion of the f e r t i l i z e r a p p l i c a t i o n s , i n good co n d i t i o n .ti from the standpoint of nutr^onal balance. This evidence plus the f a c t that growth has been so regular i n s p i t e of respec-t i v e d i f f e r e n c e s of nitrogen content of the tissues must mean that some other c o n d i t i o n e x i s t s i n the orchard that i s det-rimental to the complete welfare of the t r e e s . There has been considerable disease prevalent i n the orchard and t h i s may be a f a c t o r . But a more serious f a c t o r appears i n the f a c t that there 1ms been no means of guaranteeing a supply of water s u f f i c i e n t f o r tree needs during parts of the summer. This, therefore, f u r t h e r j u s t i f i e s the advocation of a cover crop system to increase the s o i l organic matter .content and hence i t s water-holding capacity f o r the summer months. A v a i l a b l e N u t r i e n t s and Growth Increases . I t has already been pointed out that there has been a general increase i n the a v a i l a b i l i t y of n u t r i e n t s f o r plant use. Now, i n consideration of the records of tree growth measurements, t h i s increase i n n u t r i e n t s has been manifested i n the genera.1 increase i n tree growth. In the f i r s t year of the s o i l treatments the increase i n growth has been s l i g h t and t h i s would be a r e f l e c t i o n on the past performance of the t r e e s . I t i s i n the next period that the influence of the f e r t i l i z e r treatments i s d e f i n i t e l y shown i n the tree growth. Prom the data of other workers noted i n the review 57. of l i t e r a t u r e , there i s no doubt that the extra growth res-ponse derived i n t h i s work can he a t t r i b u t e d to the nitrogen a p p l i c a t i o n s . But i t i s quite apparent that without the a d d i t i o n of the elements of phosphorous and potassium such response would not have been obtained. In f a c t , the d e c l i n -ing concentration of phosphorous throughout the period of f e r t i l i z e r a p p l i c a t i o n s , may have had a r e t a r d i n g e f f e c t on growth. The trees were absorbing i t f a s t e r than i t could be supplied and i n the future management of the orchard more phosphorous could be added to advantage. l a s t l y , the time of the year when the nitrogen was ap p l i e d has not shown, very appreciable d i f f e r e n c e s of res-ponse of tree growth. P o s s i b l y , the trees were i n such a low state of v i t a l i t y at the s t a r t that they would respond to nitrogen a p p l i e d a t any time of the year provided t h i s n i t r o -gen was not subject to leaching. The growth records of the September nitrogen treated p l o t s tend to substantiate t h i s p o s s i b l e leaching e f f e c t . CONCLUSION The f e r t i l i t y of the orchard has been brought to a po i n t where the trees have s u f f i c i e n t n u t r i e n t s f o r normal growth and f r u i t production. However, the continued mainten-ance of t h i s f e r t i l i t y i s subj ect to two l i m i t i n g f a c t o r s . The f i r s t of these i s that the state of f e r t i l i t y cannot per-s i s t due to leaching of s o i l n u t r i e n t s i n the winter months and the second i s that the water supply often reaches a l e v e l 38. too low f o r tree requirements i n the summer. The fortunate part i s that these two f a c t o r s may he o f f s e t to a large extent "by the use of a winter cover crop system which w i l l hold nu-t r i e n t s from leaching and w i l l incree.se the organic matter content of the s o i l and hence the water holding power, SUMMARY The e f f e c t s of commercial f e r t i l i z e r s were studied on a rundown orchard under B r i t i s h Columbia c o a s t a l c o n d i t i o n s . A basic a p p l i c a t i o n of phosphorous and potassium was given annually a t the end of A p r i l f o r three years and a p p l i c a t i o n s , of nitrogen as ammonium sulphate were given to respective p l o t s i n l a t e A p r i l , l a t e May, J u l y , and September f o r the same three years. Lime was ap p l i e d to one set of these exper-iments i n September of the f i r s t year. A n a l y s i s of s o i l samples showed that there was an increased breaking down of s o i l p a r t i c l e s , and t h i s was more marked where lime was app l i e d ; the n u t r i e n t l e v e l of the s o i l s o l u t i o n wa.s m a t e r i a l l y increased, t h i s n u t r i e n t l e v e l was sub-j e c t to leaching, and in d i c a t e d that a cover crop system would be of great advantage to o f f s e t t h i s leaching. A n a l y s i s of current season shoots a t the conclusion of the p r o j e c t revealed that the trees were i n good co n d i t i o n from a n u t r i t i o n a l point of view and there must be another f a c t o r , probably the water supply i n the summer, that requires a t t e n t i o n . A cover crop would br i n g about an increase i n organic matter and hence i n moisture holding a b i l i t y of the s o i l . Trunk growth measure-39 . merits of trees showed that the f e r t i l i z e r a p p l i c a t i o n s appre-c i a b l y influenced t h e i r growth, and that nitrogen a p p l i c a -tions at any time would give good response, except when leaching would occur. 40. L i t e r a t u r e Cited 1. A s s o c i a t i o n of O f f i c i a l A g r i c u l t u r a l Chemists, Methods of A n a l y s i s . 4th Ed. 1935. 2. Atkinson, H.J. S o i l S o lution studies. S c i . A g r i c . .30:233. 1938. 3. Ban, Raghbir Singh. Graduate of Uniy., of B.C. unpublished r e p o r t . 1935. 4. Brown, J . J . Successful orchard f e r t i l i z i n g . B etter E r u i t 18: 8. D'23. 5. Burd, John S. and Martin, J.C. Water displacement of s o i l s and the s o i l s o l u t i o n . Journ, Agr. S c i . V I I I . 1923. 6. Burke, E. and Mo r r i s , H.E. Nutrient elements used by leaves and growth of apple t r e e s . Plant Phys. 8:537-44. 0«33 . •7. Cameron, E.K. and E a i l y e r , G.H. The determination of small amounts of potassium i n aqueous s o l u t i o n s . Journ. Am. Chem. Soc. 25:1063-73, 1903. 8. Chandler J r . , R .3?. The replaceable potassium content of orchard s o i l s i n Maryland as a f f e c t e d by potassium ca r r y i n g f e r t i l i z e r s . Proc. A.S.H.S. 1933, 30:62. 1934. 9. ; A study of the e f f e c t of various potas-sium c a r r y i n g f e r t i l i z e r s upon the growth and y i e l d of apples and pears. Proc. A.S.H.S. 1933, 30:62. 1934. 10. Chandler, W.H. E r u i t growing. 1925. 777p. Cambridge, ;r Mass.:' Houghton M i f f l i n Co. 11. H a r r i s , G.H. Raspberry n u t r i t i o n : I I . Causes of raspberry f a i l u r e s i n the c o a s t a l area of B r i t i s h Columbia, S c i . A g r i c . 16:353. 1936 . 12. Harvey, E.M. and Murneek, A.E. R e l a t i o n of carbohydrates and nitrogen to the behaviour of apple spurs. Ore. Agr. Exp. St. B u l l . 176:1-47. 1921. 13. Hoy, B. Orchard cover crops. B.C. Dept. of A g r i c . Hort. C i r c . No, 51. 1936. 14. Kraus, E.J. and K r a y b i l l , H.R. Vegetation and reproduction w i t h s p e c i a l reference to the tomato. Ore. Agr. Exp. St.. B u l l . 149. 1918. 41, 15. Iagasse, F.S. The e f f e c t of f e r t i l i z e r s on the chemical constituents of f r u i t spurs. Proc. A.S.H.S. 1926. p.332c 16. Marsh, R.I. A d d i t i o n a l studies on the e f f e c t of commer-c i a l forms of nitrogenous f e r t i l i z e r s as appl i e d to apple tr e e s . Proc. A.S.H.S. 1934. 32:76. 1935. 17. Nicholson, H.H. and Pantin, Barbara. Autumnal dressings • of nitrogenous f e r t i l i z e r s . '• Jo-urn. A g r i c . S c i . 19:297. 18. Northwest F e r t i l i z e r Conference of H o r t i c u l t u r i s t s . 1939 repo r t . Wenatehee, Wash. 19. Overholser, E . l . and Claypool, L.L. The response of D'Anjou pears to f e r t i l i z e r s i n Central Washington. Proc. A.S.H.S. 1935. 33:299 ri? . 20. P o t t e r , G.F. Results of incorporating a heavy a p p l i c a t i o n of superphosphate deeply into an orchard s o i l . Proc. A.S.H.S. 1934. 32:70-72. 21. Proebsting, E . l . A f e r t i l i z e r t r i a l w i t h B a r t i e t t pears. Proc. A.S.H.S. 1933. 30:55. 22. E f f e c t of cover crops on the s o i l s o l u -t i o n at d i f f e r e n t depths under orchard c o n d i t i o n s . H i l -gard i a , 7: 553-84. 1933. 23. F e r t i l i z i n g deciduous f r u i t trees i n C a l i f o r n i a . Univ. C a l i f . (Berkeley) Agr. Exp. St. B u l l . 610. June 1937. 24. Richard and Wells. Am. Journ. Chem. 31:235. 1904. 25. Smock,.R.M. and Gourley, J»H. A survey of residua from s, phosphorous a p p l i c a t i o n s i n orchard s o i l s . Proc. A.S.H.S. 1931. p.509 . 26 . .Spurway, 0 ,H. So i l t e s t i n g . Mich. St. Coll... Agr. Exp. St. Tech. B u l l . 132. J u l y 1933. 27. Thomas, W. Some r e s u l t s obtained i n i n v e s t i g a t i o n s on the d i s t r i b u t i o n of nitrogen i n apple trees during a year's c y c l e . Proc. A.S.H.S. 1926. p.73-80. 28i Truog, E m i l . Determination of the r e a d i l y a v a i l a b l e phos-phorous of s o i l s . Journ. Am. Soc. - Agr on-. 1930. p. 874. 29. Wilcox, J.C. S o i l s s p e c i a l i s t , Summerland Exp. St. . P r i v a t e communication. APPENDIX A #2. TABLE "i . COMPLETE ANALYTICAL RESULTS OE CURRENT SEASON SHOOT GROWTH, JUNE 15th, 1938. P l o t Dry We ight Re-ducing Sugars Su-crose Total Sugars Hydroly-zable Polysac-charides To t a l Carbohy-drates Total 1 N i t r o -gen i c/n X o © © © o AC1 9.96 4.0 1.2 5»2 18 .9 24.1 1.288f 18.7 A02 12.98 6.6 0.1 6.7 21.8 28.5 1.197 23.8 A l 10.99 8.3 0,4 8.7 23.4 32.1 1.169 27.4 A2 16.91 5.8 2 .2 8.0 19.9 27.9 1.302 21.4 A3 9.23 5.2 2 © 5 7.7 20.4 28.1 1.372 20.4 A4 17* 53 7.2 0.1 7.3 26.5 33.8 1.372 24.6:; BC3 13 .32 1.4 1.6 3.0 . '19.6 22.6 l • 3 2 3 17.0 B l - 15.90 8.4 0.3 : 8.7 22.4 31.4 1.218 24.9 B2 14.92 7.7 0.7 8.4 21.2 29 .6 1.190 24.8 B3 14.67 4.9 0 .4 5-«3 26.2 31.5 1.334 23.6 B4 19.2 8 .8 0.2 9 .0 24.1 33 »1- 1.334 24.7 x per cent of Fresh Weight o per cent of Dry Weight. APPENDIX B 43. TABLE i . TREE-GROWTH MEASUREMENTS IN SECTION A FOR FIVE YEARS. (INCHES), P l o t Tree June March March March March March Row Mark 1935 1936 1937 1938 1939 1940 AC1 3:1 1 2 3 6:1 Buffer 3:1 2 2 3 5:1 - 2 A4 7:1 3 2 3 4 2:1 2 3 6:1 2 5 4:1 2 3 7:1 2 3 6 3:1 2 3 7:1 2 3 10.53 10.62 19.78 19.96 21.71 21.81 9.75 9.81 18.06 18.25 20.25 20.31 7.75 7.75 15.50 15.56 16.25 16.34 7.75 7.75 12.87 12.87 13.37 13.37 9 .06 9.12 20.06 20.18 21.62 21.78 5.25 5.28 12.40 12.50 12.93 13.06 11.37 11.50 19 .87 20.06 19.93 20.06 6.93 6.96 15.12 15.15 16.93 16.96 8.00 8.06 15.18 15.40 16.12 16.28 12.31 12.37 17.06 17.18 18,03 18.25 10,81 10.81 17.59 17.62 19.18 19.21 11.04 11.16 20.64 20.88 22.44 22.86 9,96 9.96 18.60 19.29 20.65 21.00 7.92 8.04 16.08 16.14 16.80 16.92 7.92 7.92 13.20 13.20 13.92 13.98 9.48 9.66 21.36 22.20 23.52 .23.88 5.54 5 .6.1 13.82 13.14 13,68 13.80 11.82 11,88 20 .40 20 . 73 20.40 20.76 7.32 7.44 16.14 16.68 18.00 18.36 8.40 8.50 16.20 16.68 17.16 17.37 13.08 13.56 18.12 18.78 19.20 19.80 11.16 11.28 18.48 18,84 20.28 21.18 11.58 12.00 21.42 22.22 23.40 24.00 10.20. 10.38 19.80 20.40 21.10 21.16 8.16 8.16 16.38 16.56 17.28 17.52 7.98 8.04 13.56 13.68 14.34 14.52 9.86 10.20 22,74 23.88 24.36 24.96 5.64 5.69 13.32 13.56 13.98 14.28 12.06 12.30 •21.00 21.12 21,00 21.36 7.68 7.80 17.10 17.40 18.84 19.26 8.64 8.88 17.10 17.70 18.00 18.60 13.98 14.46 19.32 20.04 20,46 21.24 11.52 11.76 19.38 20.04 21.24 21.84 continued. P l o t Tree June March March March March March Row' Mark 1955 1936 1957 1938 1959 1940 :1 2 3 :1 2 3 7,75 13.68 15.06 7.81 14.43 16 .62 7 .75 13 .81 15.12 7.84 14.50 16 .68 8.04 14.16 15.36 8.04 15.06 17.64 8.07 14.25 15.60 8.10 15.24 17.64 8.10 14.34 15.60 8.16 15.42 18.12 8.16 14.46 15.96 8 .28 15.72 18 .30 8 3:1 2 3 5:1 2 3 8.75 14,87 16 .18 9 .18 16.81 20 .50 8.78 15 .00 16.37 9 .25 16.93 20,50 9 .12 15.66 16 .86 9 .66 17.64 21.24 9.60 16.41 17.64 9 .84 18 .06 21.72 9.96 16.92 18.24 10 .02 18.42 22.08 10:. 20 17.52 18.48 10.32 19 .02 22.56 ;1 2 3 ;1 2 3 6 .96 14.00 15 .00 7.56 16.12 17.18 7.06 14,06 15^06 7.62 16-. 2 5 17.31 7.26 14.52 15.72 8.04 17.16 18.06 7.41 14.82 16 '.05 8.16 17.61 18.60 7.52 14.90 16.38 8.40 18.12 19 .20 7.62 15.00 16.32 8.64 18.72 19 .68 10 :1 2 ,3 ! l 2 3 7.25 18 ,03 18.75 6.31 22.84 25.06 7.40 18 .18 19 .00 6.37 23.18 25.56 7.68 18 .96 20 .04 6.48 24.12 26 .52 7.71 19 .26 20 .04 6.48 24.33 26.88 7.80 19 .62 20 .40 6,48 24.60 27.00 7.92 19.80 20 .52 6.48 24.90 27.36 11 ;1 2 3 :1 2 3 8.81 12.62 13.40 9 .12 16.79 18.50 ' 8 .87 12.75 13.56 9 .37 17.00 18 ,71 9 .18 13.08 13.80 9 .90 17.88 19 .50 9 . 1 8 13.08 13.80 ior,26 18,60 20.22 9 .18 13.20 15.92 10 .56 19 .02 21.24 9 .24 13 .32 14.28 10.92 19.68 21.24 12 3:1 2 3 ;1 2 3 8 8.78 15.43 16.25 8.42 15 .43 16.73 8 .87 15 .53 16.37 8.50 15.50 16.87 9 .24 15.99 16.80 8.70 15.90 17.40 9 .60 16 .56 17.28 8 .82 16.14 17.64 10.02 17.12 17.82 8.88 16 .32 17.88 10 .26 17 .40 18.18 9 .12 16.68 18.12 continued. P l o t Tree June March March March March March Row.. Mark 1935 1936 1937 1938 1939 1940 AC2 3 : 1 6.87 6.87 6 .96 6.99 7.08 7.08 13 2 10.96 11.00 11.28 11.37 11.46 11.52 3 11.25 11.25 11,40 11.49 11,58 11.70 7 : 1 5.90 5.93 6.12 6.24 6.30 6.48 2 11.56 11.62 12.12 1 2 » 5 V • 12.84 15.00 3 12.00 12.12 12 .48 12.72 13.08 13.44 TABLE i i . TREE-GROWTH MEASUREMENTS IN SECTION B EOR EITE YEARS. (INCHES).. P l o t Tree June March March March March March Row Mark 1935 T936 1937 1938 1939 1940 BC3 5:1 6.25 6.25 6.48 6.78 7.32 7.92 1 2 1 5 » 2 5 15.28 15.42 15.66 16.02 16.32 3 17.11 17.12 17.16 17,40 17.40 18.24 B3 2:1 6.84 6 . 9 . 6 7.20 7.50 7 .68 7 .80 2 2 24.75 24,93 26.16 27.00 28.04 28 .56 3 25.65 25.87 27.00 27.72 29.10 29 .52 6:1 ^6.87 6.93 7,44 7.56 7.80 7.80 2 15.00 15.18 15.84 16.14 16.62 16.80 3 16.81 17,00 17,64 18.06 18.42 18.60 B3: 6:1 6 .81 6.84 6.96 6.96 7.02 7.02 •x 2 9 .81 9 .81 1 0 . 0 . 8 1 0 . 0 8 10,08 10,32 3 10,93 10 .93 11.16 11.43 11.43 11.64 7:1 6,12 6.18 6.24 6 .51 6,72 7 . 2 0 2 16.12 16.28 16.92 17.49 17.94 18.60 3 16.31 16.37 17.04 17.52 18.00 18.66 B3 1:1 5.12 5.21 6.06 6,33 7 ,20 7 .32 4 2. 10 .00 10.18 11.22 12.42 12.96 1 3 . 2 0 3 11.46 11.93 13.02 1 4 . 1 6 14.70 15,18 5:1 10.06 10 ,12 10.44 10 .80 11.16 11.64 2 25.06 25.12 •26.40 28 .17 29 .34 30.48 3 27.00 27.18 28.50 30 ,24 3 1 . 4 4 32.40 continued. P l o t Tree June March Ma.rch March" Ma.rch March Row Mark 1935 1936 1937 ; 1938 1939 1940 Buffe r o <» X 7.25 7.50 8 .40 9 .78 10 .68 11,64 0 2 18.12 18.31 19 .50 21.12 22.44 23 * 52 5 19 .03 19 .18 20.46 22*08 23.40 24.84 8:1 6.81 6.87 7 .50 8.52 9.00 9 .48 2 11.62 XX ©93 13 « 3 2 15.00 15.96 16.92 3 11.93 12.18 13.56 15.36 16.08 X 7 © 2 2 B2 3:1 6 2 3 B2 4:1 7 2 3 6:1 2 3 B2 2:1 8 2 3 4:1 2 3 Buffe r 5:1 9 2 3 8:1 2 'a; •-, ; -3' B l 1:1 10 2 3 10.37 10.43 25.06 25.12 24.06 24.12 10.00 10.07 22.06 22.09 21.37 21.43 9.18 9.31 17.46 17.56 17.75 17.81 10.37 10.50 17.17 17.31 18,12 18.28 6.56 8.62 21.87 21.96 22.62 22.81 4.50 4.62 10.43 11.37 11.75 12.18 8.00 8.06 13.43 13.53 14.87 14.93 7.18 7,40 14.12 14.34 14,56 14.65 10,80 11.16 25.80 26.70 24,84 25.56 10 .32 10 .59 22.80 23.76 22.08 22.71 9,,48 9.81 17.76 18.12 18.06 18.36 10.68 1 0 . 9 8 17.76 18.18 18.72 19.20 8.76 8 22,92 23.82 23.82 24.66 5.16 5.46 13i32 15,06 14.04 16.32 8.34 8.40 13.92 14,40 15.30 15.78 8.28 9.00 15.48 16.86 15.66 17.25 11.40 11.58 27.36 27,90 26.04 26.52 10,68 10.92 24.12 25.54 23.22 23.58 9.84 10.02 18.24 18.54 18.48 18.84 11,16 11.52 18,48 18.96 19.56 20,16 8.88 9.00 24.36 25.08 25,32 25.92 6.00 6.24 17.16 18.24 17.92 19,26 8.58 8,88 14.58 15.00 15.90 16.38 9.22 10.08 17,64 18.84 18.12 19.56 B l 6 :1 2 20.00 20,81 22 .68 24.66 25.68 27,48 3 21.18 22.06 24 .00 26.07 27.08 28.92 7 :1 6.43 6,53 6.84 7.47 7 .68 7.80 8 .93 9,06 9 .48 10 .20 10.44 10 .68 3 10.25 10,37 10 .80 X X © 5 £ j 11.82 12 .36 continued. P l o t Tree June March. March March March March Row Mark 1935 1936 1937 1938 1939 1940 B l 1:1 6 .62 6.62 6.96 7.08 7.20 7 .32 12 2 10.65 .10 .71 11,28 11.34 11.64 11.82 3 10.46 10.56 10.92 11,28 11.58 11.76 7:1 8.00 8.31 9.00 9 .33 9 .54 9 .61 2 15»31 15.75 16 .98 16.19 18.42 18 .96 3 15.75 16.06 17.34 18.15 18 .78 19 .44 Buffe r 2:1 13 • 2 Removed o 5:1 6.68 6.81 7.44 7 .68 7 .74 7.80 2 11,56. 11.68 12 .60 13.05 13 ,26 13 .44 11.96 12.12 12 .96 13.44 13 .68 13.80 B4 3:1 7.43 7.53 7.68 7.74 14 o c 16,56 16.75 17,52 18 .84 3 18 .37 18 .46 19,92 20,16 6:1 6.00 '6.12 6.54 6 .60 6.66 6.72 2 12.75 13 .06 14.52 14.73 14.76 15,00 3 1 rz H R -L n_> « / _> 14.00 15.00 16 .53 16.80 17.04 B4 4:1 7.96 7.96 8.16 8 ,25 8,40 8 .52 15 2 17 .68 17.68 18,42 19.08 19.38 19 .68 3 18.00 18,00 18.84 19 .41 19 .68 20 .04 K . ] 8.93 9.09 10.20 10 .44 10 .80 10.98 2 17.81 18.00 19 .80 20.79 21,84 22.44 3 18 .62 18.87 21.12 22.05 23.04 23 .82 B4 4:1 6 .50 6 .53 6 .66 6.78 6.84 7.00 : 16 2 15.31 15.40 15.60 16.05 16 .38 16.92 3 17 .25 17 .40 17.64 18.24 18 .54 18.90 T A B L E f i i i . AVERAGED TREE-GROWTH ANNUAL INCREASES IN SECTION A. (INCHES) June March March March March Total Average 1935 1936 1937 1938 1939 Increa.se Total to to to to to June Increase Plo"t Row Tree March March March March March 1935 per 1936 1937 1938 1939 1940 to p l o t March 1940 AC1 1 3 .37 1.73 .78 1,50 1.80 6.18 5.01 6. .31 .84 1.04 1.11 .58 3.88 A4 2 3 1.15 1.15 o 3 2 .72 .42 3.74 2 .99 5 . o o : 1.05 .06 .78 .36 2.25 Buf-f e r 3 7 .34 3 .28 1.38 1.22 2.08 8.30 8,50 A3 4 2 .26 1.40 .31 ,39 .59 2.95 4.25 6 , .45 1,00 . 75 .69 .72 3 .61 5 4 ,09 2.39 1.02 1.14 . .84 5.48 7 .44 2.02 .79 1.19 .44 4.88 Buf-f e r 6 3 .40 2.60 1.74 1.62 1.98 8.34 7.20 7 .06 2.28 1.38 .84 1.50 6.06 A2 7 1 .19 ,88 .36 .12 .54 2.09 .' 4.50 4 .16 1.62 .24 .72 ,60 5.44 8 3 1.49 2 .01 1.47 1.08 6,40 5 .19 1.86 1.08 .90 1.38 5.41 puf- 9 2 .22 1.32 .78 .52 .14 2.98 4 .58 f e r .32 2 .08 1,11 1.35 1.32 6.18 A l 10 5 .55- 2.10 .81 .42 4.21 4.31 8 .90 2.01 .57 .39 .66 4.55 11 5 .25 .88 .00 .24 .54 1.91 7 ,67 2.20 1.80 .74 1.02 6.45 12 3 .31 1.26 1.41 1.52 .88 5.38 8 .29 1.13 .60 ,48 .84 5 ,44 . AC2 13 3 .04 .52 o 22 .26 .18 1 • 22 3.34 7 .21 1.05 .81 .69 2.70 5.46 w TABLE i v . AVERAGED TREE-GROWTH ANNUAL INCREASES - , IN SECTION B (INCHES). June March March March March Total Average 1935 1936 1937 1938 1939 Increase T o i a l to to to to to June Increase P l o t Row Tree March March March March March 1935 per 1936 1937 1938 1939 1940 to p l o t March \ 1940 BC3 1 5 .04 .45 .78 .90 1.74 3 .87 3.87 B3 2 2 .52 2.60 1.96 2.60 1.06 8.64 7.00 6 ,43 1.81 ,84 1.08 .36 4.52 3 6 .03 . 62 .27 .03 .48 1.43 7 .28 1.37 1.32 1.14 1.80 5.91 4 : 1 .74 2 ,98 1.61 1.95 .84 9.12 5-.. .30 2 «9 2 3.87 2.73 2 .68 12.40 Buf- 5 3 * .67 3.37 4.62 3.54 3.48 15.68 14.47 f e r 8 ,62 3.40 4.50 ; 2.16 2 .58 13 .26 B2 6 3 .18 1,77 1.9 8 1.38 1.20 6.51 5.61 7 4 .16 1,61 1.86 .96 2.02 6.61 6 - .29 : .62 .99 .27 .84 3 .01 8 2 '. 43 , .07. 2 .20 .84 1.44 4.98 4 .34 '. 2.11 1.80 1.26 1.44 6.95 Buf- 9 5 1.49 \ 4.35 4.50 . 4.06 2.66 17.06 10.51 f e r 8 : .22 ,1.04 1.02 ; .48 1.20 3,96 B l 10 1 .63 2 ©93 3.69 1.87 3.50 12.62 7.49 -V 11 7 .35 1.16 2.07 ,75 .90 5.23 12 1 .16 1.27 .54 .72 ,48 3.If 4 3.06 1.20 1.35 2.07 1.27 8 .95 Buf- 13 5 .41 : 2.39 1.17 .51 .36 4.84 4.84 f e r ; B4 14 3 .38 2.38 4.02 5.33 6 ,68 2.88 1.80 .36 .54 6.16 15 4 .00 1,78 1.32 .72 .78 4.60 5 .60 5.16 2.16 2.40 1.56 11.88 16 4 .27 .57 1.17 .69 1.06 3.76 ACKNOWLEDGEMENTS The w r i t e r wishes to extend h i s thanks to Dr. G.H. H a r r i s , Associate Professor of H o r t i c u l t u r e of the Uni-v e r s i t y of B r i t i s h Columbia i n apprec-i a t i o n of the k i n d l y supervision and general assistance given while t h i s work was being c a r r i e d out. The w r i t e r a l s o wishes to extend h i s thanks to Dr. A. F. Barss s Professor and Head of the Department of H o r t i c u l t u r e of the Uni-v e r s i t y of B r i t i s h Columbia f o r the p r o v i s i o n of the f a c i l i t i e s used i n the work and f o r the k i n d l y i n t e r e s t he has shown.
Thesis/Dissertation
eng
Agricultural Economics
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Graduate
The maintenance of fertility in orchard soils
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