UBC Theses and Dissertations

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UBC Theses and Dissertations

Effects of commercial fertilizers on the quality of the netted gem potato grown on a sandy soil of the… Longmore, Roderick Hector 1939

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EFFECTS OF COMMERCIAL FERTILIZERS ON THE QUALITY OF THE NETTED GEM POTATO GROWN ON A SANDY SOIL OF THE BRITISH COLUMBIA COASTAL AREA by R o d e r i c k He c t o r Longmore A T h e s i s s ubm i t t e d f o r t h e Degree o f MASTER OF SCIENCE IN AGRICULTURE i n the Department o f HORTICULTURE THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1939 TABLE OF CONTENTS. Page .Introduction .............. .„.».».......«. I Rev iew of L i t e r a t u r e . . . . . . . . . . . . . . « • 3 Materials and Methods .»...<> ............. 10 R e s u l t s . « . , « . . . . . . . . . . . . . . 16 Discussion . •.»» • 47 Summary and C o n c l u s i o n s <>*.*.«. . .»•• 55 Acknowledgements „ . . . „ . « . . . . <> 57 L i t e r a t u r e C i t e d , . . „ . 58 Append i x 61 I EFFECTS OF COMMERCIAL FERTILIZERS ON THE QUALITY OF /THE "NETTED: GEM" POTATO:vGROWN O F A SANDY: :SOIL OF  THE BRITISH COLUMBIA COASTAL AREA, I n t r o d u c t i o n , . P o t a t o e s fo rm one o f the f i v e p r i n c i p a l w o r l d f ood c rops and a r e among t he most w i d e l y c u l t i v a t e d o f a l l a g r i c u l t u r a l p l a n t s . They a r e e s p e c i a l l y impo r t a n t as an a r t i c l e o f d i e t w i t h the wh i t e r a c e , and i t i s s a f e to say t h a t t h e r e a re v e r y few days on wh i ch p o t a t o e s do no t f i n d a p l a c e i n one o r more o f the mea ls o f peop l e i n a l l o c c u p a t i o n s . I n f a c t the p o t a t o ran-<-ks o n l y second t o wheat i n I t s impor tance f o r human consumpt i on , bu t s i n c e t h e r e a re l a r g e q u a n t i t i e s o f p o t a t o e s f e d t o a n i m a l s , t h e i r v a l u e i n r e l a t i o n t o a n ima l n u t r i t i o n s h ou l d a l s o be r e -membered (3)© I n 1937 t h e r e were 114,350 t o n s o f p o t a t o e s p r o -duced i n B r i t i s h Co lumb ia a l o n e , w i t h a v a l u e e q u a l l i n g app rox -i m a t e l y 88 pe r c en t o f t h a t o f a l l o t h e r v e g e t a b l e s p roduced i n the p r o v i n c e i n the same y e a r ( I ) . I n v i ew o f such f a c t s i t i s ( t h e r e f o r e r e a s o n a b l e t o conc l ude t h a t any f a c t o r o r s e t o f f a c -t o r s wh i ch may a f f e c t the q u a l i t y o f p o t a t o e s i s wo r thy o f our i n t e r e s t and c o n s i d e r a t i o n * Among t ho se f a c t o r s wh i ch a re common ly - cons ide red as caus - i n g v a r i a t i o n i n the c o m p o s i t i o n o f p o t a t o e s a r e : v a r i e t y , s o i l , c l i m a t e , d i s e a s e , and degree o f m a t u r i t y ( 3 0 ) , I n r e l a -t i o n t o ••soil we must c o n s i d e r e s p e c i a l l y the q u e s t i o n o f f e r t i l -i t y , and i t i s i n t h i s c o n n e c t i o n t h a t commerc i a l f e r t i l i z e r s have p l a y e d so impo r t an t a p a r t , p a r t i c u l a r l y i n r e c e n t y e a r s . 2 A l t hough t ype o f s o i l i s g e n e r a l l y c o n s i d e r e d to a f f e c t the q u a l i t y o f p o t a t o e s , i t i s p r o b a b l e t h a t much can be done to o f f s e t any d i s advan t age s a r i s i n g i n t h i s r e g a r d ( 1 7 ) . Numerous t e s t s have*"been made by many wo rke r s r e g a r d i n g the u se o f v a r i -ous commerc i a l f e r t i l i z e r s f o r p o t a t o e s , bu t w i t h v a r y i n g r e -s u l t s . Consequen t l y i t wou ld appear t h a t the q u e s t i o n i s s t i l l an open one , and wou ld b e a r f u r t h e r i n v e s t i g a t i o n such as t h a t unde r t a ken i n t he p rob lem unde r c o n s i d e r a t i o n he re* Most consumers have p r o b a b l y e x p e r i e n c e d v a r i a t i o n s i n the t a b l e q u a l i t y o f p o t a t o e s , and i n mak ing t h e i r pu r chases have se t up i n t h e i r own minds c e r t a i n s t anda rd s wh i ch form t h e i r b a s i s f o r b u y i n g . J u s t how sound t he se s t anda rd s a r e , f r e q u e n t l y i s a deba t ab l e p o i n t , appearances v e r y o f t e n b e i n g the s o l e c r i t e r i o n . Qu i t e o f t e n p o t a t o e s f rom c e r t a i n d i s t r i c t s en j oy a p r e f e r e n c e o ve r t ho se f rom o t h e r d i s t r i c t s , bu t i t i s v e r y d o u b t f u l i f t h i s i s a sound b a s i s upon wh i ch to base our c ho i c e ( 1 7 ) . The more r e c e n t a t t empt i n B r i t i s h Co lumb ia t o have p o t a t o e s r a t e d on t h e i r s p e c i f i c g r a v i t y , i s a imed a t a more s c i e n t i f i c m a r k e t i n g b a s i s . S p e c i f i c g r a v i t y i n t h i s case i s t a k en as an i n d i c a t i o n o f d r y m a t t e r , and t h e r e f o r e t o some e x t e n t , o f t he a c t u a l n u t r i t i o n a l v a l u e ( 4 ) . The d r y m a t t e r o f p o t a t o e s w h i l e c o n s i s t i n g l a r g e l y o f s t a r c h , has a l s o i n i t a p p r e c i a b l e q u a n t i t i e s o f p r o t e i n , m i n e r a l s , roughage , and s ug -a r s . I t was t h e r e f o r e t he o b j e c t o f the t e s t s o u t l i n e d h e r e i n , to a t tempt some e s t i m a t i o n o f the v a l u e o f a number o f d i f f e r -ent commerc i a l f e r t i l i z e r t r e a tmen t s I n r e g a r d t o t h e i r e f f e c t s on these components, as w e l l as any e f f e c t s wh i ch they may have on o t h e r phases o f q u a l i t y i n p o t a t o e s . Review o f L i t e r a t u r e . Q u a l i t y I n P o t a t o e s . - Q u a l i t y i n any f o o d sugges t s p r im - a r i l y a c t u a l f o o d v a l u e ( 4 ) . Marke t q u a l i t y and c oo k i ng q u a l -i t y s h ou l d t h e r e f o r e be based i f p o s s i b l e on the n u t r i t i v e q u a l - i t y wh i ch each may i n d i c a t e . I t can h a r d l y be s a i d t h a t what has c o n s t i t u t e d market q u a l i t y o f p o t a t o e s i n the p a s t (21) i s an e f f i c i e n t c r i t e r i o n o f n u t r i t i v e q u a l i t y . Marke t g rades have been based m a i n l y on s i z e , appea rance , and f reedom f r om d i s e a s e , I n j u r y , and c e r t a i n a b n o r m a l i t i e s ( 2 1 ) . These may i n d i c a t e t o some e x t e n t the a c t u a l f o o d v a l u e , bu t t h e y cannot be depended upon t o do so ( 2 9 ) . Cook ing Q u a l i t y o - C o n s i d e r a t i o n o f c o o k i n g q u a l i t y b r i n g s f i r s t t o ou r mind the q u e s t i o n o f m e a l i n e s s ( 3 0 ) e Swee t -man (29) c o n s i d e r s t h a t i n a d d i t i o n t o t h i s , most peop l e base t h e i r e s t i m a t i o n o f c o o k i n g q u a l i t y on c o h e s i o n , c o l o u r , and f l a v o u r . That c o o k i n g q u a l i t y i s l a r g e l y a m a t t e r o f t a s t e i s shown by t he f o l l o w i n g e x t r a c t s f r om B e w e l l ( 4 ) . He quotes E,M« Eas t o f t he I l l i n o i s A g r i c u l t u r a l Expe r imen t S t a t i o n as s a y i n g : " I n P r a n c e , s ogg i ne s s i s d e s i r a b l e , s i n c e t he a c c ep t ed method o f c o o k i n g i s deep f a t f r y i n g , f o r wh i ch a t u b e r wh i ch h o l d s i t s f o rm i s d e s i r e d . I n A m e r i c a , p r o b a b l y 90 p e r c en t o f the consumpt ion i s o f b o i l e d o r baked p o t a t o e s , wh i ch a re d e s i r e d d r y and mea l y . " C o n t i n u i n g f u r t h e r he s t a t e s t h a t C . P . L ang -wo r thy o f the U n i t e d S t a t e s Department o f A g r i c u l t u r e d e f i n e s and e x p l a i n s mea l i n e s s as f o l l o w s : " I n t h i s c o u n t r y the c h i e f t e s t o f e x c e l l e n c e i s m e a l i n e s s , wh i c h means t h a t , when cooked , a p o t a t o s hou l d f o rm a c r y s t a l l i n e ^ l i k e mass, w i t h a lmos t d i s -t i n c t s t a r c h - l i k e p a r t i c l e s , , T h i s q u a l i t y depends l a r g e l y upon the p r o p o r t i o n o f s t a r c h p r e s e n t . I f i t i s abundant and e v e n l y d i s t r i b u t e d th roughou t the t u b e r , t he c e l l s b u r s t open i n cook -i n g , and a l i g h t , f l a k e y , u n i f o r m mass r e s u l t s . I f the p r o p o r -t i o n o f s t a r c h i s s m a l l i n any p a r t o f t he p o t a t o , wa te r i s l i k e l y t o r e p l a c e i t , wh i c h w i l l make the p o t a t o soggy when c ooked , " M e a l i n e s s and S t a r c h Content« - But many worke r s do no t a c cep t m e a l i n e s s as an i n f a l l i b l e i n d i c a t i o n o f s t a r c h c o n t e n t . Sweet man, wo r k i ng i n Maine (29), s t a t e s t h a t " a l t h ough t h e r e i s a g e n e r a l t endency f o r s t a r c h i n e s s and m e a l i n e s s t o he a s s o c i a t - ed i t i s c e r t a i n t h a t t h i s r e l a t i o n s h i p does no t h o l d f o r many i n d i v i d u a l t u b e r s and t u b e r l o t s . The p rob l em o f d i s c o v e r i n g the a d d i t i o n a l i n f l u e n c i n g f a c t o r or f a c t o r s r e m a i n s , " She a l s o quotes numerous o t h e r i n s t a n c e s where wo rke r s have f a i l e d t o f i n d a h i g h p o s i t i v e c o r r e l a t i o n between s t a r c h c on t en t and m e a l i n e s s . Day (9) f o und t h a t even i n mea l y p o t a t o e s , c o o k i n g i s no t c h a r a c t e r i z e d by the b r e a k i n g o f c e l l w a l l s , and Sweetman (29) suppo r t s t h i s c o n t e n t i o n i n the s t a t emen t s t h a t "most o f the c e l l w a l l s m a i n t a i n t h e i r i n t e g r i t y a f t e r an amount o f mech - a n i c a l t r ea tmen t s u f f i c i e n t t o g i v e a w e l l - mashed p r o d u c t , " and " t o e x p l a i n r e l a t i v e degrees o f m e a l i n e s s i t i s n e c e s s a r y t o seek t he r e a son f o r v a r i a t i o n i n c e l l s e p a r a t i o n i n the cook -ed p o t a t o when i t i s a p p r o p r i a t e l y m a n i p u l a t e d , " Thus i t i s s een , t h a t even among t ho se t h a t base good q u a l i t y on m e a l i n e s s , t h e r e i s d i sag reement as t o t he l a t t e r showing s t a r c h c o n t e n t . However , Sweetman ( 2 9 ) , f rom an e x t e n -s i v e r e v i ew of l i t e r a t u r e conc l udes t h a t t h e r e i s a h i g h c o r -r e l a t i o n between m e a l i n e s s and s t a r c h c o n t e n t , bu t t h i s c o r -r e l a t i o n i s no t p e r f e c t . S l o u g h i n g , o r l a c k o f c ohe s i o n i n the cooked samp le , i s a s s o c i a t e d by B e w e l l (4) i n B r i t i s h Co lumb ia w i t h h i g h d r y ma t t e r o r s t a r c h c o n t e n t , . a n d t h e r e f o r e w i t h g r ea t - e r mea l i n e s s „ He sugges t s such samples be b o i l e d more s l o w l y , o r s teamed, t o a v o i d s l ough i ngo F i s h e r ( 2 9 ) , however , found t h a t i t was p o s s i b l e to combine m e a l i n e s s and h i g h s t a r c h c on t e n t w i t h o n l y a s m a l l t endency to s l o u g h . Workers a l s o d i s a g r e e as t o the e f f e c t s o f c o o k i n g t e chn i que on s l o u g h i n g ( 2 9 ) , M e a l i n e s s and F a c t o r s o t h e r t h an S t a r c h a - I n v e s t i g a - ' . t i o n s r e g a r d i n g o t h e r f a c t o r s wh i ch may a f f e c t m e a l i n e s s have a l s o p roduced c o n f l i c t i n g r e s u l t s , , Coudon and Bus s a r d (29) thought t h a t v a r i a t i o n s i n c on t en t o f p e c t i n s m ight be r e s p o n s -i b l e f o r d i f f e r e n c e s i n t h i s r e g a r d , bu t Moore i n Maine and o t h e r worke r s found no f i x e d r e l a t i o n s h i p between the two ( 2 9 ) . Coudon and Bu s sa r d (29) c on c l uded f u r t h e r t h a t l owe r p r o t e i n con ten t was f ound I n t u b e r s o f h i g h e r s t a r c h c o n t e n t , and such samples t h e r e f o r e gave g r e a t e r m e a l i n e s s , bu t t h e i r f i n d i n g s a re c o n t r a d i c t e d by t hose o f Hare our t i n Canada (29)_, and E a s t i n the U n i t e d S t a t e s ( 2 9 ) , w h i l e Cobb (8) s u b s t a n t i a t e s them. F i s h e r wo r k i ng i n M i c h i g a n (29), i n a somewhat l i m i t e d i n v e s t i g a t i o n ^ found no c o n s i s t e n t c o r r e l a t i o n between mea l i n e s s and pe r cen tage o f f i be r® G o l d t h w a i t e i n Co l o r ado (10) f o und mea l i n e s s a s s o c i a t e d w i t h the e x t e r n a l appearances o f f i r m f l e s h , few and s h a l l o w eyes , f reedom f rom growth c r a c k s and p r o t u b e r a n c e s , and a n e t -t e d o r w e l l - s u b e r i z e d s k i n . Sweetman (29) however b e l i e v e s t h a t such c r i t e r i a a re n o t r e l i a b l e , a l t h o u g h t h e y t e nd t o e l i m i n a t e immature t u b e r s and any wh i ch have been a f f e c t e d by " h i g h l y v a r - i a b l e g row ing c o n d i t i o n s , " G i lmore a t C o r n e l l (29 V, b e l i e v e d t h a t t he r e l a t i v e p r o -p o r t i o n s o f the c o r t e x and i n n e r and o u t e r m e d u l l a r y r e g i o n s i n d i c a t e d m e a l i n e s s , and he i 3 s uppo r t ed he r e by E a s t (29) and Abbot e t a l ( 2 9 ) , However B u t l e r e t a l (29) d i s a g r e e d w i t h them, a t l e a s t i n p a r t , and Sweetman (29) c onc l ude s t h a t " a more exac t measure i s needed*" Wh i t temore and Buschke i n Rhode I s l a n d (33 ) , found t h e i r m i d - s ea son I r i s h Cobb l e r v a r i e t y more mea ly on t he average t h an t h e i r Green Moun t a i n , bu t t h e r e was no c o n s i s t e n t d i f f e r e n c e i n mea l i n e s s "between t he se v a r i e t i e s and the R u r a l Russe t • Go l d -t h w a i t e (10) and P a r k e r (29) c on c l uded t h a t q u a l i t y depended l e s s upon v a r i e t y t han upon the g rower , the s e a son , and the . s o i l , Cobb (8) f ound l ower average t empe ra tu re s p roduced b e t -t e r t e x t u r e , c o l o u r and f l a v o u r , e x c e p t i n g w i t h one v a r i e t y , F i n d l a y (29) s t a t e s t h a t i n S c o t l a n d p o t a t o e s a re more mea l y i n a d r y season t han when the r a i n f a l l i s high® The w r i t e r has no t - i c e d t h a t I n p o t a t o e s p roduced I n Saskatchewan and Man i t oba i n v e r y . d ry . / seasons , s l o u g h i n g o f t e n o c c u r s . T h i s according."to. ' . . . B e w e l l (4) i n d i c a t e s a h i g h d r y m a t t e r and s t a r c h c o n t e n t . S o i l t ype has been thought by many t o have an i m p o r t -ant b e a r i n g on q u a l i t y , P i n d l a y (29) b e l i e v e d i t t o be one o f the most impo r t an t f a c t o r s , b u t Hardehburg (29) d i s a g r e e s . The f i n d i n g s o f the l a t t e r a r e i n agreement w i t h those o f t h e w r i t - e r i n an i n v e s t i g a t i o n o f p o t a t o e s g rown ; on d i f f e r e n t s o i l t ypes i n B r i t i s h Co lumb ia (17)« Sm i th i n New Yo r k (26)^ f ound t h a t s o i l s o f pH 5 o 4 0 t o 6.05 gave p o t a t o e s v / i th h i g h e r s t a r c h c on t en t t han s o i l s o f e i t h e r l owe r o r h i g h e r pH v a l u e s . B u s h n e l l (29) t h i n k s i t p r o b -ab l e t h a t a c i d i t y o f the s u b s o i l i s an impo r t a n t f a c t o r i n r e -s t r i c t i n g r o o t g rowth and t h e r e f o r e a f f e c t i n g q u a l i t y . Tucke r i n Canada ( 3 I ) j says t h a t p o t a t o e s need r i c h s o i l f o r t h e i r b e s t deve lopment ,and advoca tes f e r t i l i z i n g f r e e l y . C h i l d and Lynch (6) compar ing p o t a t o e s grown on f e r t i l i z e d and u n f e r t i l i z e d pea t s o i l s , c o n c l u d e d t h a t f e r t i l i z a t i o n improved q u a l i t y « Whi t temore and Buschke ( 3 3 ) f ound h i g h p o t a s h t o g i v e g r e a t e r mea l i n e s s t h an low p o t a s h . They f ound the mu r i a t e o f p o t a sh s u p e r i o r to the s u l f a t e , bu t Wheldon i n Eng l and (29) j r e -p o r t s the r e v e r s e . P i n d l a y (29) f o und i n S c o t l a n d j h o w e v e r , t h a t t h i s depended on r a i n f a l l . B l a c k (5) s t a t e s t h a t p o t a s h i s the go ve r n i ng f a c t o r i n p o t a t o g r ow i ng , and w h i l e the s u l f a t e has been c o n s i d e r e d the more d e s i r a b l e f o rm i t "has no t been sub -s t a n t i a t e d by a c t u a l p r a c t i c e , " Shu t t and Wr i gh t (25) i n c l u d e p o t a t o e s among the c r op s wh i c h b e n e f i t f r om p o t a s s i c f e r t i l i -z a t i o n , s t a t i n g t h a t the s u l f a t e o f p o t a s h i s sometimes p r e f e r -r e d t o the m u r i a t e f o r them. The r e p o r t o f the Nor thwes t P e r t i l - i z e r Con fe rence o f H o r t i c u l t u r i s t s f o r 1938 (22) s t a t e s t h a t i n B r i t i s h Co lumbia u n i f o r m f e r t i l i z e r recommendat ions cannot be made t o cove r even one t ype o f c rop i n any one o f the t h r e e main s o i l a r e a s , and t h a t where phosphorus i s d e f i c i e n t n i t r o -gen-phosphorus comb ina t i on s t e nd to g i v e maximum v i n e - g r o w t h , y i e l d , and q u a l i t y . Smi th and Nash ( 2 7 ) , g row ing p o t a t o e s i n sand c u l t u r e s f ound t h a t t hose samples h a v i n g l owes t s t a r c h 8 con t en t were grown i n a comp le te c u l t u r e , a comp le te c u l t u r e minus b o r on , and a comp le te c u l t u r e minus i r o n . They found t h e h i g h e s t pe r cen t age o f s t a r c h i n t ho se grown I n a c u l t u r e w i t h a low s upp l y o f p o t a s s i u m . Ware and K imbrough (32) found t h a t the h i g h e r the r a t e o f a p p l i c a t i o n o f a comp le te f e r t i l i z e r t he low - e r was t he pe r c en t age o f t o t a l s o l i d s , s t a r c h e s , and s u g a r s , u n t i l doub le the o r i g i n a l r a t e s o f a p p l i c a t i o n were r e a ched ; above t h i s , t r e nd s were h a l t e d o r r e v e r s e d . K imbrough (15) f ound I n ano the r i n v e s t i g a t i o n w i t h B l i s s Tr iumph p o t a t o e s on new g round , t h a t v a r i o u s f e r t i l i z e r t r e a tmen t s h ad l i t t l e e f f e c t on q u a l i t y . F a c t o r s A f f e c t i n g C o l o u r o f Raw F l e s h . - Sweetman (29) s t a t e s t h a t the c o l o u r o f the f l e s h may v a r y f rom y e l l o w o r g r a y i s h t o p e r f e c t l y w h i t e , and w h i l e on t h i s c o n t i n e n t wh i t e o r n e a r l y wh i t e i s p r e f e r r e d , i n many c o u n t r i e s y e l l o w f l e s h i s i n demand. She a l s o ment ions the f a c t t h a t the a s s o c i a t i o n o f y e l l o w - f l e s h e d v a r i e t i e s w i t h h i g h e r v i t a m i n A i s o f c o n s i d e r -a b l e i n t e r e s t , R a t h l e f (20) s t a t e s t h a t c o l o u r o f f l e s h I s d e -t e rm i ned l a r g e l y by i n h e r i t a n c e , a l t h o u g h i t may be i n f l u e n c e d to some e x t e n t by env i r onmen t , wea t he r , f e r t i l i z e r s , h e a l t h con - d i t i o n s o f the p l a n t , e t c . H i l l a t Ottawa (13) f ound t h a t t u b -e r s grown i n sand c u l t u r e s ^ n o t r e c e i v i n g b o r o n , h a d s l i g h t l y y e l l o w f l e s h a f t e r c o o k i n g , and Sm i th and Nash (27) s e cu r ed s lm - i l a r r e s u l t s . F a c t o r s A f f e c t i n g C o l o u r o f Cooked F l e s h , - Hantke ( I I ) s t a t e s t h a t expe r imen t s conduc ted a t the U n i v e r s i t y o f W i s c o n -s i n l e d t o the c o n c l u s i o n s t h a t the s upp l y o f z i n c , copper ,man-ganese , and bo ron i n the s o i l may a f f e c t the amount o f b l a c k e n -9 i n po t a t oe s a f t e r c o o k i n g , and a l s o t h a t a l i b e r a l use o f p o t -ass ium i n f e r t i l i z e r s may have an i n f l u e n c e i n t h i s r e g a r d , by-d e l a y i n g u n f a v o r a b l e r e sponses o f the p l a n t to a l a c k o f b o r o n 0 He a l s o s t a t e s t h a t the amount o f mo i s t u r e i n the s o i l I n f l u e n -ces b l a c k e n i n g , t h a t h e a t may have a more impo r t a n t i n f l u e n c e than o t h e r c l i m a t i c f a c t o r s I n t h i s r e g a r d , and t h a t imma t u r i t y o f v i n e s a t t ime o f h a r v e s t i n g does no t g r e a t l y a f f e c t the b l a c k e n i n g p r o c e s s • B e w e l l (4) f ound t h a t p o t a t o e s w i t h l ower d r y ma t t e r c on t en t t u r n e d da rk a f t e r b e i n g cooked and a l l o w e d t o stando F a c t o r s A f f e c t i n g F l a v o u r » - A c c o r d i n g t o Sweetman (29) f l a v o u r i n p o t a t o e s , as i n o t h e r foods i s a c omb i na t i o n o f s m e l l and t a s t e s e n s a t i o n s , and t h a t s i n c e t he aroma i s o n l y s l i g h t and d i f f i c u l t t o e v a l u a t e i t i s u s u a l l y no t c o n s i d e r e d c A c c o r d i n g t o h e r , a t l e a s t f o u r groups o f compounds a f f e c t t he t a s t e o f p o t a t o e s • These a r e : s uga r s , o r g a n i c a c i d s , ash c o n -s t i t u e n t s and s o l a n i n . B & t l e r e t a l (29) c on c l u ded t h a t swee t -ness o f f l a v o u r d i d no t i n a l l v a r i e t i e s depend on q u a n t i t i e s o f r e d u c i n g suga rs p r e s e n t , bu t s i n c e p o t a t o e s may c o n t a i n much l a r g e r amounts o f s u c r o s e , t he l a t t e r , wh i c h was no t d e -t e rm i n ed by them, wou ld have t o be c o n s i d e r e d a l s o i n r e l a t i o n t o sweetness ( 2 9 ) . C h i l d and Lynch (6) f ound t h a t d e s i r a b l e f l a v o u r i n p o t a t o e s tends t o c o r r e l a t e p o s i t i v e l y w i t h m e a l i -n e s s , and t h ey are suppo r t ed he re by Cobb (8)-. Montana e x p e r i -menters (29) found t h a t t u b e r s o f the N e t t e d Gem v a r i e t y b e -came y e l l o w i s h - g r e e n and somewhat b i t t e r and a c r i d i n f l a v o u r when s t o r e d i n a humid atmosphere a t 40°F„ T h i s d i d no t o c cu r a t t empera tu res o f 53°or 6 0 ° F 0 Sm i th and Nash i n New Yo r k (27) 10 found t h a t where bo r on was no t added to the s o i l the p o t a t o e s p roduced t h e r e f r om "had a f l a t f l a v o u r , d e f i n i t e l y I n f e r i o r t o those w i t h b o r o n . " The l a t t e r were m i l d i n f l a v o u r and "were judged as e x c e l l e n t i n t e x t u r e and f l a v o u r . " Other C o n s i d e r a t i o n s i n Regard t o Q u a l i t y . - I n the l i t e r a t u r e a l r e a d y r e v i ewed many o f t he p o i n t s conce rned w i t h n u t -r i t i v e q u a l i t y have been d i s c u s s e d . The f i g u r e s as g i v e n by d l f f e r e n t i n v e s t i g a t o r s , f o r the c ompo s i t i o n o f p o t a t o e s , v a r i e s somewhat (24 ,29) , b u t i t w i l l be seen t h a t i n a d d i t i o n to c a r b o -h y d r a t e s t h e r e a re v a r y i n g amounts o f p r o t e i n , f i b r e , a s h , and f a t . Ash c o n s t i t u e n t s i n c l ude , among o t h e r m i n e r a l s , a p p r e c i a b l e q u a n t i t i e s o f p o t a s s i u m , c h l o r i n e , phospho rus , magnesium, c a l -c i um, sod ium, and I r o n ( 2 4 , 2 9 ) . S m a l l e r amounts o f s i l i c o n , s u l f u r , a luminum, manganese and o t h e r s o c cu r ( 2 9 ) . Ave rages as g i v e n f o r the v a r i o u s c o n s t i t u e n t s however o f t e n mean l i t t l e , due to the g r ea t r anges t h a t a re o f t e n f ound ( 2 9 ) . Most o f the work w i t h f e r t i l i z e r s appears t o be conce rn ed w i t h t h e i r i n f l u e n c e on y i e l d s 9 ( 2 9 ) , bu t more r e c e n t l y some c o n s i d e r a t i o n has been g i v e n to f e r t i l i z e r e f f e c t s on v a r i o u s phases o f q u a l i t y , as shown i n the l i t e r a t u r e r e v i ewed h e r e . M a t e r i a l s ^ and.?Methods » F i e l d Wo rk . - The g round s e l e c t e d f o r the t e s t s I s l o c a t ed i n the h o r t i c u l t u r a l s e c t i o n o f the U n i v e r s i t y o f B r i t i s h Co lumb ia f a r m . Each p l o t was 20 f e e t l o n g and the s e r i e s o f p l o t s ex tended f rom n e a r the U n i v e r s i t y f o r e s t e a s t w a r d . The s o i l i n t h i s a r e a i s a sand and the exposure i s w e s t e r l y . S m a l l , c e r t i f i e d seed o f the N e t t e d Gem v a r i e t y was s e -cu red f rom Pember ton , B .C . t h r ough the B r i t i s h Co lumb ia P o t a t o I I B oa r d , The t u b e r s v a r i e d i n we i gh t f rom 1 , 5 t o 3 , 0 o z . , and were c u t once , l e n g t h w i s e , g i v i n g s e t s a v e r a g i n g 1 , 0 o z . P l a n t -i n g was made a t a dep th o f a p p r o x i m a t e l y 4 i n c h e s . Rows were 2 0 f e e t l o n g and 3 f e e t apa r t , w i t h the s e t s 18 i n c h e s apa r t i n the row . Each p l o t c o n s i s t e d o f 2 r ows , w i t h a b u f f e r row o r a 5 f o o t wa l k s e p a r a t i n g i t f rom the n e x t one . Dates o f p l a n t i n g were 'June 4 and 5 , F e r t i l i z e r t r e a tmen t s were made I n d u p l i c a t e and were as f o l l o w s : I , — Comp le te , 2 c — Superphosphate + Po t a s s i um C h l o r i d e • 3 , — Ammonium S u l f a t e + Po t a s s i um C h l o r i d e s 4 « - - Ammonium S u l f a t e •+ Supe rphospha te . 5 , - - Ammonium Phospha te + P o t a s s i u m C h l o r i d e , 6 , — Po t a s s i um C h l o r i d e , 7 , - - Complete + B o r a x , 8, — Complete + Manganese S u l f a t e , 9 , - - Complete + S u l f u r , 1 0 , - - Complete ,-f- Gypsum e I I A m m o n i u m S u l f a t e -~ J u l y 10 , 1 2 , — Ammonium S u l f a t e + I r o n S u l f a t e , 13 , - - Ammonium S u l f a t e — Aug , 1 7 , 1 4 , - - U n f e r t i l i z e d c h e c k . The comp le te f e r t i l i z e r u s ed was a 5 - 1 0 - 5 m i x t u r e o f ammonium s u l f a t e , supe rphospha te , and po t a s s i um c h l o r i d e , The r a t e s o f a p p l i c a t i o n t o g e t h e r w i t h the numbers o f the p l o t s a re g i v e n i n Tab le I , The f e r t i l i z e r s were a p p l i e d J u l y 1 0 , e x c e p t -i n g one o f the ammonium s u l f a t e t r ea tmen t s^wh i ch was a p p l i e d 12 FERTILIZER TREATMENTS P l o t s N0 9 - F e r t i l i z e r A p p l i c a t i o n i n l b s , p e r a c r e F e r t i l i z e r A p p l i c a t i o n , i n l b s , p e r a c r e I & 15 Complete 900 2 & 16 Super -phosphate 635 K C l ISO 3 & 17 (NE\J^S0 + 360 K C l 180 4 & 18 (mJA so„ 360 Super -phosphate 635 5 & 19 K C l 180 (NH 4 ) 3 PO^ 550 6 & 20 KOI 180 7 & 21 Complete 900 : Bo rax 30 : 8 & 22 Complete 900 •MnSO^: 60 9 & 23 Complete 900 S u l f u r 240 10 & 24 Complete 900 Gypsum 2300 11 & 25 (NH 4 ) 4 S0^ 325 . 12 & 26 ,('MH4)»S0* 325 FeSO^. 90 13 & 27 (NH^^SO^ 325 14 & 28 .. None --- _ TABLE I , PLOTS AND FERTILIZER TREATMENTS. F e r t i l i z e r was a p p l i e d t o p l o t s 13 and 27 on August 17 , bu t t o a l l o t h e r p l o t s on J u l y 10•< P l o t 15 r e c e i v e d the same f e r t i l i z e r as p l o t I , p l o t 16 t he same as 2 , and s i m i l a r l y p l o t s 17 - 28, t h e same f e r t i l -i z e r as p l o t s 3 - 14 r e s p e c t i v e l y . 13 August 17 , They were b r o a d c a s t by hand and r a ked i n . The p l o t s were s p r i n k l e d immed i a t e l y a f t e r w a r d s bu t were o t h e rw i s e u n -i r r i g a t e d . The p o t a t o e s were h a r v e s t e d on September 24 and 25 , and were s t o r e d i n sacks i n an unhea ted room o f the h o r t i c u l t u r e b u i l d i n g . Records were made o f the t o t a l y i e l d s and a l s o o f the amounts o f s m a l l and second-g rowth t u b e r s , a s measures o f market q u a l i t y . Where t u b e r s a re c l a s s e d as ma r ke t ab l e o r s a l e a b l e t hey were judged, by s i g h t t o f a l l w i t h i n t he B r i t i s h Co lumb ia Marke t g r a d e s . D e t e r m i n a t i o n s on the T u b e r s , - As o t h e r p o s s i b l e measure - s o f q u a l i t y the f o l l o w i n g d e t e r m i n a t i o n s were made on the po t - a t o samp les : ( I ) T i t r a t a b l e a c i d i t y , (2) E l e c t r i c a l r e s i s t a n c e o f the j u i c e , (3) S p e c i f i c g r a v i t y , (4) Dry w e i g h t , (5) P r o t e i n (6) Reduc ing s u g a r s P (7) T o t a l s u g a r s , (8) S t a r c h , (9) T o t a l a s h , (10) P o t a s s i u m , ( I I ) C a l c i u m , (12) Magnesium, (13) I r o n , (14) Phospho ru s , (15) C h l o r i n e , and (16) Cook ing Q u a l i t y , Samples o f p o t a t o e s f o r mak ing t h e s e t e s t s were made up by t a k i n g 12 t u b e r s as n e a r l y r e p r e s e n t a t i v e as p o s s i b l e o f the e n t i r e l o t conce rned and c u t t i n g out c r o s s - s e c t i o n s t h rough the m i d d l e , e x c e p t i n g i n the case o f s p e c i f i c g r a v i t y and c oo k i ng q u a l i t y , where the e n t i r e t u b e r s were u s e d , T i t r a t a b l e a c i d i t y was de te rm ined by t i t r a t i o n a g a i n s t t e n t h no rma l sodium h y d r o x i d e • E l e c t r i c a l r e s i s t a n c e o f the j u i c e was c a l c u l a t e d by means o f a S tuden t p o t e n t i o m e t e r u s ed as a Wheatstone b r i d g e . The j u i c e u s ed i n t he t e s t s was e x t r a c t e d by p u t t i n g t u b e r s t h rough a f ood chopper and squee z i ng t he m i x t u r e o f p u l p and 14 j u i c e i n a wh i t e c o t t o n b a g . S p e c i f i c g r a v i t y d e t e r m i n a t i o n s were based on we igh t o f the samples i n a i r and t h e i r l o s s o f we i gh t i n w a t e r . To o b t a i n the we i gh t o f the sample i n w a t e r , i t was p l a c e d i n an open -mesh w i r e ba ske t and immersed i n wa te r i n a l a r g e t i n c o n t a i n e r . The ba ske t was-suspended on two l o n g w i r e s a t t a c h e d to the ends o f a wooden s t r a p wh i c h was l a i d a c r o s s the t a b l e o f the s c a l e . C o r r e c t i o n s were made f o r v a r i a t i o n s i n the t empera tu re o f t he w a t e r . Dry we i gh t was c a l c u l a t e d by c u t t i n g IGO grams o f the t u be r s i n t o t h i n s l i c e s and d r y i n g these i n an oven a t a temper -a t u r e o f 5 0 ° - 65°C f o r 48 h o u r s , o r u n t i l c o n s t a n t i n w e i g h t . P r o t e i n was de t e rm ined by t he K j e l d a h l method, u s i n g I gram o f d r i e d m a t e r i a l . T o t a l n i t r o g e n o u s ma t t e r was c a l c u l a t e d on the b a s i s o f N x 6 . 2 5 , Sugars were de t e rm ined b y t he Lane and Enyon Method (2) a f t e r a l c o h o l e x t r a c t i o n o f 100 grams o f f r e s h - w e i g h t i n the S o xh l e t a p p a r a t u s . A c i d h y d r o l y s i s o f the S o x h l e t r e s i d u e was u sed to c a l -c u l a t e s t a r c h c o n t e n t . Ash d e t e r m i n a t i o n s were made by h e a t i n g 5 grams o f d r i e d m a t e r i a l i n a hood u n t i l smok ing c ea sed , and c o m p l e t i n g the i n -c i n e r a t i o n i n a f u r n a c e . A n a l y s i s o f the ash f o r v a r i o u s m i n e r -a l s was c a r r i e d out as f o l l o w s : (1) P o t a s s i u m - S h e r r i l 1 s method ( 2 ) , (2) C a l c i um - R i c h a r d and W e l l s ' method ( 2 3 ) , (3) Magnesium - Hubba rd ' s method ( 1 4 ) , (4) I r o n - Method as u s e d by Spurway ( 2 8 ) , 15 (5) Phosphorus - P a r ke s and Fudge ' s method ( 1 9 ) . u s i n g 0 . 3 gram o f d r i e d m a t e r i a l . (6) C h l o r i n e - Method o f the A s s o c i a t i o n o f O f f i c i a l A g r i c u l t u r a l Chemis t s ( 2 ) . Cook i ng t e s t s i n c l u d e d bo t h s team ing and b o i l i n g . Qua ! - i t y was s c o r ed on a s i m i l a r s y s t em t o t h a t g i v e n by Z a v i t z (34) The s 'cale o f p o i n t s u s e d was: ( 1 ) M e a l i n e s s —• ~ 40 p o i n t s . (2) F l a v o u r — 40 p o i n t s . (3) C o l o u r when cooked — • - - 20 p o i n t s . T o t a l -~ 100 p o i n t s . The schemebof:^gfcading:rwasaas-::f©llows: (1) M e a l i n e s s : V e r y mea ly - 40, Mea l y - 34 , S l i g h t l y mea ly - 28 , S l i g h t l y soggy - 22 , S o g g y - 16, V e r y soggy - 1 0 0 (2) F l a v o u r : E x c e l l e n t - 4 0 , V e r y good - 34 , good - 2 8 , F a i r l y good - 22 , Soggy - 16, V e r y soggy - 1 0 . (3) Co l ou r when cooked: V e r y wh i t e - 20 , Wh i te - 16 , Creamy wh i t e - 12 , Cream - 8 , L i g h t y e l l o w - 4 . Market q u a l i t y was de t e rm ined by s o r t i n g ou t the second -g rowth t u be r s and those judged a t s i g h t to be too s m a l l t o come w i t h i n the B r i t i s h Co lumb ia market grades ( 2 1 ) . The we i gh t s o f t he se were c a l c u l a t e d as p e r c en t age s o f the t o t a l y i e l d s f rom the p l o t s . S o i l T e s t s . - M e c h a n i c a l and c h e m i c a l a n a l y s i s o f the s o i l samples were made. The samples were t a ken on June 21 - 23 , by d i g g i n g t h r e e h o l e s i n each p l o t , one a t each o f two o ppo s i t e c o r ne r s and one i n the c e n t r e . A f t e r each h o l e was c l e a r e d o f s o i l , f u r t h e r s o i l was c u t o f f i n t h i n l a y e r s f rom the s i d e s ^ i n 16 such a manner as t o secure as r e p r e s e n t a t i v e a sample as p o s s -i b l e down t o a dep th o f 12 i n ches* The s o i l samples were then m i xed t h o r o u g h l y , a i r d r i e d and s t o r e d u n t i l needed,, M e c h a n i c a l a n a l y s i s was c a r r i e d out by c e n t r i f u g i n g about 5 c c . o f s o i l sample i n a hand c e n t r i f u g e * The s o i l was p l a c e d i n g r adua ted c e n t r i f u g e tubes and enough wate r added to b r i n g the volume to 12 c c . The tubes were then shaken to ensure t h o r ough m i x i n g o f the wate r and s o i l , w h i r l e d i n the c e n t r i f u g e f o r t h r e e to f o u r m i n u t e s , removed, and a l l o w e d to s t and i n an u p r i g h t p o s i t i o n f o r some t i m e . When a l l bu t t he a p p a r e n t l y c o l l o i d a l m a t e r i a l had s e t t l e d ou t , the amounts o f each o f t h e d i f f e r e n t c l a s s e s o f s o i l p a r t i c l e s were then r e a d and p e r c en t ages o f t o t a l volume c a l c u l a t e d . Compara t i ve amounts o f c o l l -o i d a l m a t e r i a l were a l s o n o t e d . I n mak ing the c h e m i c a l a n a l y s i s o f t he s o i l s , the e x t r a c t i n g s o l u t i o n as u sed by Morgan (18) was emp loyed . T e s t s were made f o r n i t r a t e s , phospho rus , p o t a s s i u m , c a l c i u m , magnesium, i r o n , a luminum, and s u l f a t e s , u s i n g the methods as employed by Spurway (28) „ The s o i l r e a c t i o n was t e s t e d by the Lamotte -Morgan s o i l t e s t i n g method ( 1 6 ) . R e s u l t s . The r e s u l t s o b t a i n e d f rom each, p a i r o f p l o t s r e c e i v i n g the same f e r t i l i z e r a p p l i c a t i o n have been ave raged and t a ken as the r e s u l t s f o r t h a t p a r t i c u l a r t r e a t m e n t . These averages a re g i v e n i n the f o l l o w i n g t a b l e s , w h i l e r e s u l t s f rom each o f the i n d i v i d u a l p l o t s a re appended. R e s u l t s o f s o i l a n a l y s i s a r e , however , l i s t e d o n l y once and f o r each o f the p l o t s sep -a r a t e l y e 1 7 F e r t i l i z e r Complete Supe r -phosphate +KC1 ( N H A SO* +KC1 ( r a j . so* +Super-phosphate KC1+(NHJ, P 0 + KC1 Complete + Bo rax Complete +MhSO+ Complete +S Complete + Gypsum (NH J a S0«. so., +FeSO* ( N H j * SO* ( A u g . 1 7 ) None Y i e l d p e r a c r e ( l b s ) 20,419 1 7 , 5 1 5 1 6 , 7 8 9 20,097 19,240 1 8 , 7 6 6 19,190 14,793 1 5 , 9 7 3 15,973 15,156 13,704 11,798 11,707 % S a l e a b l e 7 3 . 9 7 1 . 6 5 9 . 3 5 4 . 3 6 4 . 5 7 2 . 6 63<,4 7 1 # J . 6 9 . 9 6 6 . 5 6 1 * 4 6 8 . 1 6 1 . 9 5 7 . 3 % Second growth 13 , 1 15 ,4 22 .6 33 .9 17*3 14 .3 I 9 e 2 13 . 5 13 . 3 12 .8 2 I o 0 10.6 12 08 % Sma l l 1 3 . 0 1 3 . 0 1 8 . 1 I I . 8 18 © 2 X3 $ X 1 7 . 4 1 5 . 4 1 6 . 8 2 0 . 7 1 7 * 6 1 7 . 7 2 7 . 5 2 9 o 9 TABLE 2 9 FERTILIZER TREATMENTS IN RELATION TO MARKET QUALITY. 18 I n t a b l e 2 a t t e n t i o n s h o u l d be drawn t o th© f a c t t h a t the comp le te f e r t i l i z e r p roduced the l a r g e s t y i e l d and a l s o the h i g h e s t pe r cen t age o f ma r ke t ab l e t u b e r s . The ammonium s u l f a t e - p l u s - s u p e r p h o s p h a t e t r ea tmen t c l o s e l y app rox ima ted i t i n t o t a l y i e l d bu t f e l l much be low i t i n the q u a n t i t y o f mar -k e t a b l e p o t a t o e s p r oduced , b e i n g the l owes t o f a l l t r e a tmen t s i h : : t h i s r e g a r d . The po t a s s i um ch l o r i d e -p l u s - ammon ium phosphate p l o t s a l s o s t o o d c o m p a r a t i v e l y h i g h i n y i e l d , bu t a g a i n o n l y about t w o - t h i r d s o f t h i s was m a r k e t a b l e . As m igh t be e xpe c t ed the u n f e r t i l i z e d p l o t s gave t he l owes t t o t a l , y i e l d . They were a l s o second l owe s t i n the amount o f ma rke t ab l e t ube r s producede The t r e a tmen t o f ammonium s u l f a t e a p p l i e d l a t e i n the season gave r e s u l t s o n l y s l i g h t l y b e t t e r , b u t i n t h i s c o n n e c t i o n i t s h o u l d be remembered t h a t the f e r t i l i z e r was a p p l i e d o n l y a s h o r t t ime b e f o r e the v i n e s were s t r u c k by l a t e b l i g h t . I t w i l l be seen on e x a m i n a t i o n o f s u c c eed i ng t a b l e s a l s o , t h a t t h i s t r e a tmen t and the check p l o t s s t ood c l o s e t o g e t h e r i n most o f the r e s u l t s o b t a i n e d I n the v a r i o u s a n a l y s e s made. Y i e l d s v a r i e d f rom ove r 10 t on s t o a l i t t l e l e s s t han 6 tons p e r a c r e w i t h an average o f a p p r o x i m a t e l y 8 . 3 t ons p e r a c r e . Pe r cen t age s a l e a b l e v a r i e d f rom 73 . 95 t o 54 .3 and ave raged 6 5 . 4 4 . C o n s i d e r a b l e range i s shown i n b o t h c a s e s . 19 F e r t i l i z e r S p e c i f i c G r a v i t y % Dry Weight Complete ' :i I . 0 7 1 7 2 0 . 4 0 Sup e rpho sphate + k c i 1 . 8 7 5 8 2 0 . 4 9 ( N H 4 ) ^ S 0 4 + K C 1 I«©768 2 1 . 4 1 ( N H ; J X S O 4 + Superphosphate 1 , 0 7 6 9 2 1 . 29 KCI + (NHJ^PO^. 1 . 0 7 3 3 2 1 . 7 7 KCI 1 . 0 7 5 8 2 1 , 2 8 Complete + Bo rax I 9 0 ! ? 3 9 . 2 1 , 8 1 Complete + MnSO* 1 . 0 7 4 6 2 1 . 8 0 Complete + S 1 . 0 7 5 2 2 2 . 2 9 Complete -+ Gypsum . 1 . 0 7 5 0 ' ' . 2 1 . 5 1 1 , 0 7 5 6 . 2 1 . 1 0 FeSO«. 1 , 0 7 8 3 2 2 . 6 7 ( N H - J , so* ( A u g . 1 7 ) 1 . 0 8 2 3 2 2 . 3 6 Hone 1 . 0 8 2 4 2 2 . 7 0 ' TABLE 3. FERTILIZER TREATMENTS IN RELATION TO SPECIFIC GRAVITY AND DRY WEIGHT. 20 C o n s i d e r i n g f i r s t s p e c i f i c g r a v i t y , we f i n d t h a t the check p l o t s s t and f i r s t , c l o s e l y f o l l o w e d "by the l a t e t r e a tmen t o f ammonium s u l f a t e and the ammonium s u l f a t e - p l u s - i r o n s u l f a t e t r e a t m e n t o The p l o t s r e c e i v i n g the comp le te t r ea tmen t gave p o t -a t oe s h a v i n g the l owe s t s p e c i f i c g r a v i t y . When d r y we i gh t i s c o n s i d e r e d the check i s a g a i n h i g h e s t and the comp le te t r e a tmen t l o w e s t , bu t the o t h e r t r e a t -ments d i f f e r somewhat i n t h e i r d r y we i gh t s t a nd i n g s f rom t h e i r r a n k i n g s on s p e c i f i c g r a v i t y . The range i n s c o r e f o r bo th d r y we igh t and s p e c i f i c g r a v i t y i s however , no t v e r y g r e a t . S p e c i f -i c g r a v i t y s c o r e s range f rom 1,0717 t o 1,0824 w i t h an average o f 1 ,0762, D ry ma t t e r v a r i e s f rom 20 .4 t o 22 ,7 and ave rages 2 1 . 6 3 . 21 F e r t i l i z e r Complete Superphosphate + KC l " ( W H + ) x S 0 4 * K C l (NHJ^SQ^ Superphosphate K C l -i- (NHj^PO^. K C l Complete+Borax CompletetMnSO^ Complete + S Complete •+ Gypsum (NH„) xSO^ ( N H 4 - L SO.,* (Aug . IV ) None % S t a r c h 16 .40 I 6 e 6 3 16*53 16 .25 I 6 0 5 2 16 ,14 16 .54 16 .30 17 .00 I 6 „ 52 15.36 16.16 16 .19 16 .40 % Dry Weight 20 .40 20.49 21 ,41 21 0 29 21,77 21 ©28 21 ,81 21,80 22 0 29 21 © 5X 21 ,10 22.67 22,36 22 .70 TABLE 4, FERTILIZER TREATMENTS IN RELATION TO STARCH AND DRY WEIGHT. 22 The comp le te p l u s s u l f u r shows the h i g h e s t s t a r c h c on t en t and the ammonium s u l f a t e l e a s t . W i t h the e x c e p t i o n o f the l a t t e r t r ea tmen t however , t h e r e i s a v e r y nar row range i n s t a r c h c o n t e n t , wh i c h i f t he ammonium s u l f a t e t r e a tmen t i s o m i t t e d , v a r i e s f rom 16 ,14 t o 17 , 0 p e r c e n t . The average s t a r c h c on t en t f o r a l l 14 t r e a tmen t s i s I 6 „ 3 I pe r c e n t ; and 12 o f the samples f a l l w i t h i n o n e - h a l f o f one pe r c en t o f each o t h e r i n s t a r c h . There i s however a c o n s i d e r a b l e d i f f e r e n c e between the h i g h e s t s t a r c h c on t en t o f 17 ,0 pe r c en t and the l o w e s t , I 5 0 3 6 pe r c e n t . 23 F e r t i l i z e r Reduc i ng Sugars % T o t a l Sugars Complete Go 340 0 ,490 Superphosphate + KCI 0 ,350 0 .430 (NH 4 ) £ S0 4 + KCI 0 ,375 0 ,455 ( N H j , S0 4 + Superphosphate 0 ,450 0 .690 KCI + (NH 4 ) , EO^ 0,415 0 ,735 KCI 0 ,660 0 ,940 Complete + Bo rax 0 .570 0«760 Complete + MnSO^ 0 S 5 4 0 0*740 Complete * S 0 ,590 0*755 Complete + Gypsum • 0 .465 0*685 0 0 4 5 0 •0^ .60© (NH 4 ) a S 0 4 f FeSO^. 0 ,615 0 S 8Y0 ( H H j „ so+ (Aug.17) 0 ,540 0 .690 None 0 ,595 0,755 TABLE 5 . FERTILIZER TREATMENTS IN RELATION TO SUGARS, 24 Reduc i ng suga rs are l owe s t i n t he comple te t r e a t -ment w i t h 0 .34 pe r c en t and h i g h e s t a t 0 .66 pe r cen t i n the po t a s s i um c h l o r i d e t r e a t m e n t , i n wh i ch t h e y a r e a lmos t doub le t hose o f t he f o r m e r . As s e en , t h e range i s c o n s i d e r a b l e . The average f o r a l l samples i s 0 .497 p e r c e n t . T o t a l s uga r s a l s o v a r y c o n s i d e r a b l y , the s upe r -phosphate p l u s p o t a s s i um c h l o r i d e t r ea tmen t b e i n g l owes t w i t h 0 .43 pe r c en t and po t a s s i um c h l o r i d e a g a i n h i g h e s t w i t h 0 .94 p e r c e n t . The average s t ands a t 0 .685 pe r c e n t . 25 F e r t i l i z e r $ P r o t e i n % S t a r c h Complete 1.5360 16 .40 Superphosphate + K C l I . 5315 1 6 , 6 3 (NH 4 ) a S0 A + K C l 1.5640 16 ,53 ( N H J x SQ* + SuperphOsphate I . 8815 1 6 , 2 5 K C l + ( N H 4 ) 3 P 0 4 1.6665 16 ,52 K C l 2.0135 16.14 Complete Bo rax 2 , 2 2 7 0 16.54 Complete + MnSO^ 1 , 6 6 7 0 16.30 Complete + S 1.7835 17 .00 Complete Gypsum I .5165 16 .52 ( N H j a SO^ 1.7200 15.36 ( M L ^ S0 4-» FeSO+ I . 9715 I6«I6 (NH*) a S 0 A ( A u g . I 7 ) 1.7800 16.19 None 1*7365 16 .40 TABLE 6 . FERTILIZER TREATMENTS IN RELATION TO PROTEIN AND STARCH CONTENT. 26 V a r i a t i o n i n the p r o t e i n c on t en t was a l s o c o n s i d -e r a b l e , b e i n g l owe s t i n the comp le te p l u s gypsum p l o t s a t I.5165 p e r c en t and h i g h e s t i n the comp le te p l u s bo ron t r e a t -ment a t 2,227 p e r c e n t . Average p r o t e i n con t en t was 1,7568 p e r -cen t On the who le t ho se r a n k i n g h i g h i n p r o t e i n a re r e l a t i v e l y l owe r I n s t a r c h bu t the r e l a t i o n appears t o be o n l y g e n e r a l . 27 F e r t i l i z e r T o t a l Ash Complete 0.8465 Superphosphate •* KCI 0 .7410 : (BH 4 ) a S 0 4 * KCI 0 .7710 ( H H 4 ) a S 0 4 + , Superphosphate 0 .7425 KCI -t- (NH 4 ) 3 P0 4 . 0 .7725 KCI 0.6890 Complete + Bo rax 0.7400 Complete •+ MhSO .^ 0 .7260 Complete •+ S 0^7665 Complete •+ Gypsum 0.8675 (NH 4 LSO« 0.8140 ( N H „ k S 0 4 * FeSO^. 0*6930 ( N H O a S 0 A ( A u g . I 7 ) 0 .7165 None 0 .8305 TABLE 7 , FERTILIZER TREATMENTS IN RELATION TO TOTAL ASH. 28 H i g h e s t t o t a l ash was found i n the c o m p l e t e - p l u s - g y p -sum t r ea tmen t wh i ch gave 0 ,8675 p e r c e n t . The po t a s s i um c h l o r -i d e p l o t s p roduced the sample w i t h l e a s t a s h , h a v i n g 0 ,689 pe r c e n t . The sp r ead I s t h e r e f o r e no t g r e a t and the average o f 0 ,7665 p e r cen t g i v e s a f a i r i n d i c a t i o n o f the ash i n most o f the samp le s . 29 F e r t i l i z e r K Ca Mg P 01 Fe Complete 251 6 , 2 19 ,2 51 .7 36 ,3 1.60 Superphosphate + K C l 282 8 .2 8 ,4 44 . 8 49 .6 1,10 ( N H - ^ S O ^ K C l 314 8 ,4 19 ,9 28 .1 31 , 0 I . I O (NEU^SO^* Superphosphate 209 6 , 3 17 ,8 47 . 3 32 , 5 1.10 K C l (NH 4 ) 3 PQ+ 210 25 ,2 37 .8 55 e 9 I . I O K C l 237 6 .5 16 .9 33 . 4 43 ,7 0 ,85 Complete + Bo rax 167 9 ,6 XX o 3 48 .6 39 © 3 0 .60 Complete + MnSO*. 248 " :' 6 ,6 ..' ;: 13 .2 51 ,6 46 .6 1.05 Complete + S 162 6 ,5 27 .7 ; "41.6 ] 41 . 4 0 .60 Complete + Gypsum 244 8 . 3 13 .3 45 . 3 29 « o 0 ,65 (NEULSO^. 234 ; 6 , 8 23 .©• 2 8 . 4 : 38 ,6 X o 55, FeSO*. 218 6 ,7 X4L © 2 36 , 7 36 . 1 I © 55 (ITHv)* S0<. (Aug,17) 218 4 , 9 I©., 4 28 © 3 41 $ 3 1.35 None 234 5 © X 11 ,0 31 , 1 2X o 2 1,10 TABLE 8 FERTILIZER TREATMENTS IN RELATION TO:MINERAL CONTENT. 30 F i g u r e s g i v e n i n t h i s t a b l e r e p r e s e n t i n a l l cases m i l l -i g rams o f t he p a r t i c u l a r m i n e r a l f o und i n .100 grams o f f r e s h we i gh t • P o t a s s i um v a r i e d f r om 162 i n the p o t a t o e s f rom t he com-p l e t e - p l u s - s u l f u r t r e a tmen t t o 314 i n t hose f rom t he ammonium s u l f a t e - p l u s - p o t a s s i u m c h l o r i d e p l o t s , and ave raged 230*6. The v a r i a t i o n s a r e n o t e s p e c i a l l y s t r i k i n g excep t i n t he cases o f the h i g h e s t and two l owe s t f i g u r e s . , wh i c h a re c o n s i d e r a b l y h i g h -e r and l owe r r e s p e c t i v e l y t han those f i g u r e s s t a n d i n g nex t i n o r d e r . C a l c i um was h i g h e s t i n p o t a t o e s f rom the c o m p l e t e - p l u s -b o r o n t r e a tmen t and l o w e s t i n t ho se f r om p l o t s r e c e i v i n g the l a t e a p p l i c a t i o n o f ammonium s u l f a t e . C a l c i u m con ten t v a r i e d from; 9.6 t o 4 . 9 and ave raged 6 . 9 , the range b e i n g somewhat g r e a t e r p r o p o r t i o n a t e l y t h an i n the case o f p o t a s s i u m . G r e a t e s t c ompa ra t i v e v a r i a t i o n was f ound i n magnesium con t en t wh i c h was h i g h e s t a t 27 .7 i n the c o m p l e t e - p l u s - s u l f u r sample and l owes t a t 8*4 i n t u b e r s f rom the p l o t s t r e a t e d w i t h superphosphate p l u s po t a s s i um c h l o r i d e . The average magnesium f ound was 16.5® C o n s i d e r a b l e v a r i a t i o n a l s o o c c u r r e d i n phosphorus,, wh i ch r anged f rom 2 8 0 I i n p o t a t o e s f rom the ammonium s u l f a t e t r ea tmen t , t o 51 .7 i n the comple te t r e a t m e n t , and showed an average o f 3 9 . 6 , Next to magnesium, c h l o r i n e gave the g r e a t e s t compar-a t i v e v a r i a t i o n . The check p l o t s s t o od l owes t w i t h 21 .2 and the po t a s s i um ch l o r i d e -p l u s - ammon ium phosphate h i g h e s t w i t h 31 5 5 , 9 , The average was 3 8 , 8 , I r o n r anged f rom 0 ,6 i n the c o m p l e t e - p l u s - b o r o n and c o m p l e t e - p l u s - s u l f u r t r ea tmen t s^to 1,6 i n the comp le te , t hus showing a c o n s i d e r a b l e v a r i a t i o n . The average i r o n c on t en t wa I . I , The samples f rom the check p l o t s and f rom those r e c e i i n g an a p p l i c a t i o n o f ammonium s u l f a t e l a t e i n the season , were the o n l y ones wh i ch were q u i t e low as compared w i t h the o t h e r s : i n most o f t he m i n e r a l s f o r wh i c h a n a l y s e s were made. •32 F e r t i l i z e r Complete Superpho sphate 4 KC I ( N H 4) aS0„ + KCI ( N H j ^ S O ^ Superphosphate KCI * (NH«) 3 PO^ KCI Complete * Bo rax Complete •* MnSO^ Complete + S Complete -t Gypsum ( N H 4 L S0 4 (NHj^SO** FeSO^. ( N H j a S0« (Aug . I 7 ) None R e s i s t a n c e i n Ohms 104.7 I02o2 101 . 2 107.8 108 .9 106 .1 XQ2 © 2 99 . 1 97 .7 Q5 © 2 93^8 102 .9 91 .4 93 . 1 .TABLE 9, FERTILIZER TREATTvIENTS IN RELATION TO ELECTRICAL RESISTANCE, 33 E l e c t r i c a l r e s i s t a n c e t e s t s showed l i t t l e v a r i a t i o n . The range f rom h i g h e s t t o l o w e s t was o n l y 1 7 . 5 ohms r e s i s t a n c e and the average 100.5 ohms. S i n c e t h e r e were d i f f e r e n c e s i n exces s o f 30 ohms r e s i s t a n c e i n t e s t s o f p o t a t o e s f rom d u p l i -c a t e p l o t s t he range as shown wou l d be o f no s i g n i f i c a n c e (see a p p e n d i x ) . 34 F e r t i l i z e r Complete Superphosphate 4 KCI (HHJ^SO** KCI (NH 4)» SCU.+ Superphosphate KCI + ( N H j 3 P O ^ KCI Complete + Borax Complete «+• MnSO* Complete •+ S Complete 4 Gypsum •(NH+)±SO* ( N H j * S 0 4 * FeSO^. (NH . J a S0 , , (Aug . I 7 ) None Cos , o f O . I / N NaOH u sed 31 .8 32 , 3 34 .0 36 , 0 33 . 0 31 .0 37 . 0 36 , 0 3 5 e 3 31 . 5 53 .0 33 © 5 39 e 3 36 .0 TABLE 10, FERTILIZER TREATMENTS IN RELATION TO TITRATABLE ACIDITY® 35 The range i n a c i d i t y o f the samples was no t v e r y great© The most a c i d p o t a t o e s were p roduced by t he l a t e a p p l i -c a t i o n o f ammonium s u l f a t e and the l e a s t a c i d sample by t he po t a s s i um c h l o r i d e treatment® I n t he t i t r a t i o n s t h e r e was a sp r ead o f 9 . 3 c o . I n the volume o f t e n t h no rma l sodium h y d r o x -i d e u s e d . The l a r g e s t volume u s ed was 3 9 , 3 c c . and the s m a l l e s t 3 I « 0 c c . , the average b e i n g 3 4 0 3 c c . 3 6 F e r t i l i z e r Cook ing Score Complete 6 1 Superpho sena te * K C l 6 8 (NH j^ S0«.+ K C l 6 4 ( N H J ^ S O ^ * - Superphosphate 6 5 K C l + ( N H j . P O ^ 5 7 K C l 5 1 -- Complete * Bo rax 5 6 Complete <+ MnSO^ 6 4 Complete + S 6 0 Complete -+• Gypsum 6 1 ( N H A L SO*. 7 4 (NEU) a S0 4 + FeSO^. 7 2 ( N H J * SO^Uug.17) 6 9 None •'•'•71 - : FERTILIZER^ TREATMENTS IN RELATION TO COOKING SCORE. 37 Prom t a b l e I I i t i s seen t h a t none o f the samples s t and v e r y h i g h i n c o o k i n g s c o r e . There i s a s p r e ad o f 23 p o i n t s b e -tween t he h i g h e s t and l owes t s c o r e s , t he average b e i n g app r o x -i m a t e l y 6 4 . Those t r e a tmen t s i n wh i ch s u l f a t e s have been used a l o n e J s t a n d h i g h e s t . The comple te t r ea tmen t i s c o m p a r a t i v e l y low i n s c o r e j a n d the check c o m p a r a t i v e l y h i g h 0 V a r i a t i o n s i n s c o r e a r e p r i n c i p a l l y due t o d i f f e r e n c e s i n m e a l i n e s s , c o l o u r and f l a v o u r b e i n g c o m p a r a t i v e l y c o n s t a n t . TABLE 1 2 . CHEMICAL ANALYSIS o f SOIL SAMPLES. 38 P l o t p H N 0 a • P K Ca Mg ; Fe A l so^. I 5 e 7 2 8 0 , 5 9 185 0 8 . 4 0 2 5 o 7 28 0 o 4 1 0 1 5 0 T 8 4 G 3 6*5 27 0 * 4 I I 1 7 5 T 8 4 • 0 4 5 .9 13 1 . 5 1 0 180 T 8 3 0 5 6 .5 4 1 . 0 .10 ' 1 8 0 ... 7 - : :: ' , 4 ': 0 6 6 , 5 6 0 , 5 15 150 © 7.; ; 4 © . • 7' 6 . 2 , 25/ 0 . 5 200 10 3 ' ; © , ' ' 8 6 ,7 T ' • 5 19© T 8 4 0 9 . 5 . 7 . ; - - 5 . . I 2 200 0 8 4 0 i o • • 6 . 1 '20 I « . 3 6 1 5 0 0, 10 4 0 I I 6 , 3 2 1,5 5 1 7 0 0 1 0 4 0 1 2 6 . 0 . 7 1 , 5 10 1 7 0 0 1 0 5 © 13 5 .9 18 T 5 1 5 0 0 10 4 0 14 6 ,3 18 1,5 9 1 6 0 0 15 5 0 TABLE 1 2 . CHEMICAL ANALYSIS OF SOIL SAMPLES. Numbers i n d i c a t e p a r t s per" m i l l i o n . T - T r a c e , 39 P l o t pH . MO,. P K Ca Mg Fe A l s o ^ 15 6 .5 28 0 ,5 10 I5G T 9 5 0 16 6 .3 28 0 e 5 4 150 T 10 4 0 17 6 .3 3 T 9 170 0 I I 4 ' 0 18 6 . 1 I T 6 150 0 8 4 0 19 6 .3 2 T 6 150 © : •:'. 10 • 4 0 20 J 6 . 7 6 ; . : '0 : 7 180 0 10 5 0 21 6 .3 27 T 190 0 I© 5 0 22 6 .5 5 : 0 , 5 185 'G ; 10 4 0 23 6 ,3 7 ' 1*0 12 160 0 10 4 0 24 0*6 • 2 ' 1.5 •'-'9,' 180 T 8 • 4,.-; 0 25 6 ,7 4 2 ,0 20 200 '"' - .o' j 10 3 ,. o 26 ; 6 .5 I •i.*7 20 200 0 " 8 4 o ; 27 6 ,7 30 2 ,0 .6 195 0 10 2 0 28 6*;7;'-' 30 2 ,0 10 . 195 o : io ••; TABLE 12 . ( c on t i nued ) CHEMICAL ANALYSIS OF SOIL SAMPLES. Numbers i n d i c a t e p a r t s pe r m i l l i o n . T = T r a c e , 40 Chem i ca l a n a l y s i s o f t he s o i l s showed 8 o f the 28 p l o t s t o be low i n n i t r a t e s , w i t h t he o t h e r s v a r y i n g . f r o m medium t o h i g h . I t was i n t h i s n u t r i e n t , h o w e v e r , t h a t t he g r e a t e s t v a r i a -t i o n o c c u r r e d . Phosphorus was low i n 18 o f the p l o t s w i t h none r e g i s t e r i n g as h i g h as medium. Po t a sh was low i n o n l y 3 p l o t s , 2 b e i n g mode r a t e l y h i g h and the r ema inde r medium. Ca l c i um was a p p a r e n t l y adequate i n a l l o f the p l o t s , w i t h a tendency t o be h i g h i n 20 out o f the e n t i r e 28• Magnesium was p r e s en t o n l y i n t r a c e s , and t h en o n l y i n 7 o f the samp les , the rema inde r g i v i n g b l a n k t e s t s . I r o n showed l i t t l e v a r i a t i o n , bu t was a p p a r e n t l y p r e s en t i n s u f f i c i e n t q u a n t i t i e s i n a l l the p l o t s . Aluminum t e s t s a l s o showed l i t t l e v a r i a t i o n . S u l f a t e t e s t s gave b l a n k r e ad i ng s i n a l l i n s t a n c e s . S o i l r e a c t i o n t e s t s v a r i e d f rom pH 5.7 t o pH 6 . 7 , a l l samples b e i n g on the a c i d s i d e bu t none e s p e c i a l l y s o . TABLE 1 3 . MECHANICAL ANALYSIS OP SOIL . 41 P l o t : # G r a v e l % Sand % S i l t 4 7° F i b e r ^ Humus C o l l o i d a l m a t t e r 8 80 4 - 5 3 medium low 2 8 81 4 5 2 medium low 3 8 78 4 8 '. 2 medium 4 • 9 81 3 5 2 » 5 ; : i r . | 80 • 3 4 • 2 ii 6 '. -77 ', 4 , - ' '5 2 medium low : 7 13 76" 4 5 ."2 medium 8 13 74 7 4 2 I! 9 ' 1 5 75 4 4 2 H IO : ' 14 74 6 4 • '2'-. " 11 I I 17 73 4 4 • • 2 '• " n 12 18 72 5 3 2 '• it 13 19 74 3 2 2 n 14 19 69 7 '3 >• 2 it TABLE 1 5 . MECHANICAL ANALYSIS O F j O I L . 42 P l o t % G r a v e l % Sand % S i l t % F i b e r % Humus C o l l o i d a l ^ ma t t e r 15 I I 81 3 3 2 medium 16 18 75 5 I 2 1! 17 18 73 4 3 2 ir 18 17 74 5 2 2 II 19 20 72 5 I 2 H 20 19 71 7 I . : 2 tl 21 12 78 4 4 . . 2 . II 22 16 ' 74 • -5 \ ' • 3 . 2 II 23 18 72 . 4 . 4 2 It 24 17 73 5 " 3 : 2 II 25 20 72 I 2 11 26 21 69 7 I 2 II 27 20 • 73 4 I 2 u 28 20 73, 4 I 2 it TABLE 1 3 . ( c o n t i n u ed ) MECHANICAL ANALYSIS OF SOIL . 45 I n m e c h a n i c a l c o m p o s i t i o n a l l the s o i l samples were d e c i d e d l y sandy, w i t h a c e r t a i n amount o f v a r i a t i o n i n g r a v e l c o n t e n t . S i l t , f i b e r , and humus were a l l q u i t e low and compar-a t i v e l y c o n s t a n t . C o l l o i d a l ma t t e r was v e r y c on s t an t i n a l l b u t t h r e e samp l e s . TABLE 14 , WEATHER RECORD. 44 Bate Temperatures R a i n Date Tempera tures R a i n June M i n , Max, June M i n . Max. I. 58 77 25 59 73 2 58 68 26 57 79 3 52 66 27 60 85 4 52 73 28 60 84 5 56 84 29 54 78 6 60 85 30 : 55 73 7 55 77 J u l y 8 55 73 I 61 76 9 55 J1A L i g h t 2 55 73 10 55 71 Heavy ' 3 56 75 I I 56 73 Heavy * 4 55 76 12 I - 57: 77 5 m:. 76 • . i s ; 76 L i g h t 6 m 75 14 57 79 Heavy 7 56 74 15 •'••59. 69 , ' Medium 8 .54 79 16 54 64 Heavy .' 9 ,. • ..53 80 17 . ' 5 3 59 Medium 10 55 78 , y '•• 18 54 73;: Heavy I I 60 75 •19 54 69 L i g h t 12 61 80 20 55 72 L i g h t 13 • 57 74 Medium 21 56 : 72 ' L i g h t 14 58 78 22 56 \ -.71 Heavy 15 61 79 23 53 67 Heavy 16 \ 62 81 ! 24 53 •! .• 73 . ' 17 62 85 TABLE 14 , WEATHER RECORD. 45 Date Temperatures •Rain Date Temperatures Ra i n J u l y M i n . Max. Aug . M i n , Max, 18 59 74 10 62 64 'Heavy 19 58 79 I I 63 79 20 61 81 12 62 78 L i g h t 21 56 78 13 61 70 L i g h t 22 62 76 14 49 69 L i g h t 23 60 76 15 50 66 24 63 86 16 57 69 25 69 81 17 57 76 26 61 78 18 ,/ 56 77 27 61 81 19 54 74 28 61 74 20 56 77 : 29 59 73 21 , 57 67 Heavy 30 57 73 H e a v y - : 22 57 69 Heavy 31 56 76 23 58 '•" 73 Heavy Aug , 24 57 70 I 54 74 25 58 72 L i g h t 2 56 77 26 57 71 3 57 80 27 52 69 4 59 79 L i g h t 28 52 67 5 62 76 L i g h t 29 49 71 L i g h t 6 58 65 30 57 65 ; Heavy 7 57 7^: L i g h t 31 56 72 L i g h t . 8 58 73 L i g h t 9 57 . 77 -TABLE 14 . ( c on t i nued ) 46 I t - i s t o be seen f rom t a b l e 14 t h a t the r a i n s were e s p e c i a l l y f r e q u e n t and heavy d u r i n g t he month o f June ,and o c c -u r r e d a l s o a t numerous i n t e r v a l s t h roughou t t he rema inde r o f the summer© Though i t I s g e n e r a l l y conceded t h a t weather c o n -d i t i o n s a t t he U n i v e r s i t y f a rm wou ld d i f f e r t o some e x t en t f rom those e x p e r i e n c e d a t t he Vancouver c i t y m e t e o r o l o g i c a l s t a t i o n , the r e c o r d s f r om the l a t t e r w i l l g i v e us some f u r t h e r i n d i c a t i o n o f the c l i m a t i c c o n d i t i o n s unde r wh i ch the po t a t oe s were grown (7) • Con sequen t l y t o supplement t a b l e 14 i t s hou l d be no t ed t h a t the Vancouver r e c o r d s show a r a i n f a l l f o r June , J u l y , and August o f a p p r o x i m a t e l y t w i c e t h a t o f t he 36 yea r average*, As m igh t be e xpec t ed a l s o , the r e l a t i v e h u m i d i t y was h i g h e r t h an average d u r i n g each o f t hese same t h r e e months and the hou r s o f b r i g h t sunsh ine were c o n s i d e r a b l y l e s s t h an n o r -ma l i n June and Augu s t , b u t about the same as o t h e r y e a r s i n J u l y 0 The mean mon th l y t empe ra tu r e s were s l i g h t l y h i g h e r i n June and J u l y and e x a c t l y average f o r A u g u s t 0 47 D i s c u s s i o n , The a p p l i c a t i o n o f f e r t i l i z e r s o f v a r i o u s k i n d s t o s o i l s i n wh i ch p o t a t o c r op s have been grown has l o n g been p r a c -t i s e d , and i s g e n e r a l l y conceded t o have b e n e f i c i a l e f f e c t s on y i e l d . C o n s i d e r a t i o n o f y i e l d i s o f p r i m a r y Importance t o the p r o d u c e r , f rom t he economic s t a n d p o i n t , bu t as soon as marke t g rades and p r e f e r e n c e s become e s t a b l i s h e d , t h en q u a l i t y i n i t s v a r i o u s a s pe c t s must a l s o be c o n s i d e r e d as w e l l as q u a n t i t y . I n t h i s p r o j e c t we have endeavoured t o g i v e a more o r l e s s d e t a i l e d a n a l y s i s o f a number o f p o t a t o samples and the s o i l s i n wh i ch t h e y were grown, t o show the e f f e c t s , i f any , o f a number o f d i f f e r e n t c ommer c i a l f e r t i l i z e r t r e a tmen t s on v a r i o u s a s pe c t s o f q u a l i t y . F o r conven ience the r e s u l t s w i l l be c o n s i d e r e d unde r t h r e e h e a d i n g s , namely: ( I ) Marke t Q u a l i t y , (2) Cook i ng Q u a l i t y , and (3) N u t r i t i v e Q u a l i t y . Marke t Q u a l i t y , - As market q u a l i t y i s a t p r e s e n t measured , the o n l y t e s t s conduc ted i n t h i s p r o j e c t t h a t wou ld g i v e i n d i c a t i o n s o f s u ch , a r e : ( I ) T o t a l Y i e l d , and (2) P e r -cen tage S a l e a b l e , From the s t a n d p o i n t o f t o t a l y i e l d i t i s e v i d e n t t h a t any o f the f e r t i l i z e r t r e a tmen t s u s e d a re s u p e r i o r t o the use o f no f e r t i l i z e r , unde r c o n d i t i o n s such as p e r t a i n e d h e r e . T h i s I n c r e a s e i n y i e l d s e cu r ed by use o f commerc i a l f e r t i l i z -e r s i s i n k e ep i n g w i t h the u s u a l f i n d i n g s 0 The use o f a com-p l e t e f e r t i l i z e r gave t he b e s t y i e l d , b u t t h a t o b t a i n e d f rom the p l o t s r e c e i v i n g the ammonium s u l f a t e p l u s superphosphate was o n l y s l i g h t l y l e s s . The po t a s s i um ch l o r i de -p l u s - ammon ium phosphate and c o m p l e t e - p l u s - b o r a x t r ea tmen t swere a l s o r e l a t i v e -48 l y high© Po t a s s i um c h l o r i d e u s e d a lone gave a y i e l d l ower than any o f the f o u r t r e a tmen t s j u s t men t i oned , a l t hough i t has been s t a t e d t h a t p o t a s h i s the d e t e r m i n i n g f a c t o r i n p o t a t o g row ing ( 5 ) . I n t hose p l o t s where no n i t r o g e n f e r t i l i z e r was a p p l i e d , and where the ammonium s u l f a t e was a p p l i e d o n l y a s h o r t t ime b e f o r e the p l a n t s were s t r u c k by l a t e b l i g h t , the s o i l a n a l y s i s showed n i t r a t e s t o be p r e s e n t i n s u f f i c i e n t l y l a r g e q u a n t i t i e s f o r good growth ( 2 8 ) 0 Consequen t l y none o f the p l o t s were r e a l l y l a c k i n g i n n i t r o g e n , and t h e r e f o r e none o f the l ower y i e l d s o b t a i n e d can be a t t r i b u t e d t o a sho r t age o f t h i s n u t r i -ent i n the so i i® C o n s i d e r a t i o n o f the pe r cen tage o f s a l e a b l e t u b e r s p r o -duced , shows t h a t the comp le te t r e a tmen t a l s o gave b e s t r e s u l t s i n t h i s r e g a r d , bu t the ammonium s u l f a t e p l u s superphosphate t r ea tmen t gave o n l y s l i g h t l y ove r h a l f o f the t o t a l y i e l d as marke t ab l e t u b e r s 0 Of the unmarke tab l e p o r t i o n f rom t he se l a t t -e r p l o t s o ve r 1b% were second growth t u b e r s s t h i s p a r t i c u l a r f e r t i l i z e r t r ea tmen t g i v i n g a much h i g h e r p r o p o r t i o n o f t h i s t ype o f p rod&e t t han any o f the o t h e r t r e a t m e n t s 0 I f the re -s u i t s i n the d u p l i c a t e p l o t s a re compared (see a p p e n d i x ) , i t w i l l be seen t h a t i n b o t h cases t h i s f e r t i l i z e r t r ea tmen t s t ands h i g h e s t i n the pe r cen t age o f second - g rowth t u b e r s p r o du c ed . Secondary t u b e r s a re u s u a l l y a t t r i b u t e d t o the d r y -i n g out o f the p o t a t o e s d u r i n g some p e r i o d o f t h e i r growth ( 3 0 ) , bu t s i n c e m o i s t u r e c o n d i t i o n s appeared t o be s a t i s f a c -t o r y a t a l l t imes d u r i n g the season ( Tab l e 14 ) , t h i s sugg-= e s t s t h a t a complete - minus - p o t a s s i um t r ea tmen t may cause 49 excess second g r ow th . Om i s s i on o f phosphorus f rom the complete t r ea tmen t gave the second l a r g e s t pe r cen tage o f second growth ' bu t the r e s u l t s a re n o t n e a r l y so marked as i n t he p l o t s where p o t a s h was o m i t t e d . Cook i ng Q u a l i t y 9 - Cook i ng q u a l i t y as i t has been s c o r e d i n t h e s e r e s u l t s i s b a sed on: ( I ) M e a l i n e s s o r t e x t u r e , (2) F l a v o u r , and (3) C o l o u r . There was p r a c t i c a l l y no s l o u g h i n g i n any o f t he c o o k i n g t e s t s so t h a t t h i s f a c t o r was no t c o n s i d e r e d i n s c o r i n g the samp l e s . I t t h e r e f o r e seemed a d v i s a b l e to c o n -s i d e r h e r e : ( I ) Dry m a t t e r , (2) S p e c i f i c g r a v i t y , (3) S t a r c h , (4) Suga r s , (5) P r o t e i n , and (6) T o t a l a s h , i n t h e i r g e n e r a l r e l a t i o n t o c o o k i n g s c o r e . Dry ma t t e r was f ound h i g h e s t i n the check p l o t s and l ow -e s t i n the comp le te t r e a t m e n t . T h i s i s j u s t t he o p p o s i t e o f t h e i r r ank i n r e s p e c t t o t o t a l y i e l d . There i s a s i m i l a r l y n e g -a t i v e c o r r e l a t i o n between y i e l d and d r y m a t t e r i n some o f the o t h e r samp les , and t h e r e appears t o be on the whole a g e n e r a l tendency f o r h i g h y i e l d t o g i v e low d r y m a t t e r . T h i s i s i n k e e p i n g t o some e x t e n t w i t h the f i n d i n g s o f Ware and Kimbrough ( 3 2 ) 0 The average d r y m a t t e r was a l i t t l e be low f i g u r e s u s u a l l y quo ted ( 2 9 ) . When we compare d r y m a t t e r w i t h c o o k i n g sco re ,we f i n d t h a t a l t h o u g h t h e r e i s a s i m i l a r degree o f r e l a t i o n s h i p t o t h a t between y i e l d and d r y m a t t e r , t h i s r e l a t i o n i s i n the n a t -u r e o f a p o s i t i v e c o r r e l a t i o n wh i c h i s l e s s s t r o n g l y marked . I t can t h e r e f o r e be s a i d "that as f a r as r e s u l t s show h e r e , t h e r e I s o n l y a g e n e r a l t endency f o r h i g h c o o k i n g s co re to be a s s o c -i a t e d w i t h h i g h d r y m a t t e r . 50 S p e c i f i c g r a v i t y shows a g e n e r a l t endency t o c o r r e l a t e p o s i t i v e l y w i t h d r y m a t t e r , bu t a g r e a t e r t endency towards a p o s i t i v e c o r r e l a t i o n w i t h c o o k i n g s c o r e . The t u be r s f rom the check p l o t s a re h i g h e s t i n s p e c i f i c g r a v i t y and d r y m a t t e r , and t h i r d i n c o o k i n g s c o r e , On the o t h e r hand those f rom the ammonium s u l f a t e t r ea tmen t a r e f i r s t i n c o o k i n g s c o r e , bu t t w e l f t h and e i g h t h r e s p e c t i v e l y i n d r y ma t t e r and s p e c i f i c g r a v i t y * Thus i t w i l l be seen t h a t t h e r e i s , t o a l i m i t e d de -g r e e , a p o s i t i v e c o r r e l a t i o n between d r y m a t t e r , s p e c i f i c g r av -i t y , and c o o k i n g s c o r e , bu t i t cannot be s a i d t h a t i t i s s t r o n g - l y marked . S t a r c h a l s o shows a t r e n d towards a p o s i t i v e c o r r e l a t i o n w i t h d r y m a t t e r , b u t l i t t l e c o r r e l a t i o n , p o s i t i v e o r n e g a t i v e , w i t h c o o k i n g s co r e o r s p e c i f i c g r a v i t y . The sample h i g h e s t i n s t a r c h came f rom t he c o m p l e t e - p l u s - s u l f u r t r e a t m e n t , and on the who l e , where t he comp le te f e r t i l i z e r was u s e d a l one o r i n c o m b i n a t i o n s , t h e r e was a t endency towards h i g h e r s t a r c h c o n -t e n t . There was, however , r ema r kab l y l i t t l e v a r i a t i o n I n the s t a r c h c on t en t ~of most o f the samp le s . Compar i son w i t h She r -man 's f i g u r e f o r t o t a l c a r bohyd r a t e s (24) i n p o t a t o e s , wou ld i n d i c a t e t h a t a f t e r due a l l owance i s made f o r the amounts o f o t h e r c a r bohyd r a t e s p r e s e n t , s t a r c h i n a l l samples was be low a ve r age . I t s h o u l d be n o t e d i n c o n n e c t i o n w i t h the da t a con -c e r n i n g s t a r c h y t h a t v a r i a t i o n s i n c o o k i n g s c o r e were l a r g e l y due t o d i f f e r e n c e s i n m e a l i n e s s , c o l o u r and f l a v o u r b e i n g r e l -a t i v e l y c o n s t a n t . I t wou ld t h e r e f o r e seem i l l o g i c a l i n t h i s case t o a s s o c i a t e h i g h e r s t a r c h c on t en t w i t h g r e a t e r mea l i n e s s s i n c e the v a r i a t i o n i n the l a t t e r was c o m p a r a t i v e l y much g r e a t -51 e r t han i n t he f o r m e r . Sugars were h i g h e s t i n the po t a s s i um c h l o r i d e t r e a t -ment . wh i c h gave t u b e r s e l e v e n t h i n d r y m a t t e r , and on the who le t h e r e -appeared t o be l i t t l e c o r r e l a t i o n , e i t h e r p o s i t i v e o r n e g a t i v e between suga r c on t en t and d r y m a t t e r c The amounts o f suga r f o u n d , i n compar i son t o t o t a l d r y m a t t e r , were no t enough t o g r e a t l y i n f l u e n c e the compara t i ve amounts o f the l a t t e r f ound i n the samp les , however . There was a s l i g h t t e n -dency towards a n e g a t i v e c o r r e l a t i o n between sugar c on t en t and c o o k i n g score© H i ghe s t p r o t e i n was found i n the p o t a t o e s f rom the p l o t s r e c e i v i n g a comple te f e r t i l i z e r p l u s b o r a x , wh i ch were second l owes t i n c o o k i n g s c o r e , and t h e r e was a g e n e r a l t enden-cy shown f o r h i g h e r p r o t e i n c on t en t t o be a s s o c i a t e d w i t h l ow -e r c o o k i n g score„, as i n the case o f s u g a r s . The average p ro -t e i n f ound was be low t h a t u s u a l l y quo ted f o r p o t a t o e s ( 2 9 ) 0 I n t e n out o f f o u r t e e n samples a n a l y s e d , h i g h ash c on -t e n t was a s s o c i a t e d w i t h low p r o t e i n . T h i s i s the h i g h e s t c o r r e l a t i o n f ound anywhere i n the r e s u l t s . The c o m p l e t e - p l u s -gyp sum t r ea tmen t gave h i g h e s t ash and l owes t p r o t e i n and the po t a s s i um c h l o r i d e t r ea tmen t gave a lmos t the r e v e r s e . As might be e xpe c t ed , t h e r e f o r e , h i g h ash c on t en t i s f o r the most p a r t a s s o c i a t e d w i t h low c o o k i n g s c o r e . Average ash c on t en t was a l s o low ( 2 9 ) . An e x am i na t i o n o f f e r t i l i z e r t r e a tmen t s i n d i r e c t r e -l a t i o n t o c o o k i n g s co re shows t h a t the two t r ea tmen t s wh i ch gave b e s t s c o r e s i n t h i s r e g a r d , were a p p l i c a t i o n s o f s u l f a t e . Where superphosphate was combined w i t h s u l f a t e s the c o o k i n g 52 s co r e was a l s o c o m p a r a t i v e l y h i g h , bu t t h e r e appears t o be l i t t l e c o n n e c t i o n w i t h h i g h e r c o o k i n g s co re and s u l f a t e s as u s e d i n the comp le te t r e a t m e n t , o r i n the t r e a tmen t s where the comp le te f e r t i l i z e r was u s ed i n c omb i na t i o n w i t h o t h e r subs tan -ces© The p o s s i b i l i t y o f s u l f a t e s b e i n g s i g n i f i c a n t i s f u r t h e r borne out by the f a c t t h a t t e s t s f o r s u l f a t e s i n the s o i l samples gave b l a n k r e s u l t s , and a l s o by the f i n d i n g s o f H a r r i s ( 1 2 ) , N u t r i t i v e Q u a l i t y , - A number o f the c o n s t i t u e n t s wh i ch de te rm ine the n u t r i t i v e q u a l i t y o f p o t a t o e s have a l r e a d y been d i s c u s s e d u n d e r c ook i ng q u a l i t y . As n o t e d , the a n a l y s i s o f the p o t a t o samples showed t h a t , o f the v a r i o u s c o n s t i t u e n t s wh i ch go t o make up d r y m a t t e r , s t a r c h , p r o t e i n , and ash were l o w e r , and t o t a l s uga r s h i g h e r t han t he averages g i v e n f o r p o t a t o e s by v a r i o u s worke r s (24 , 2 9 ) , The v a r i o u s f e r t i l i z e r t r e a tmen t s p roduced a compar-a t i v e l y na r row range i n s t a r c h c on t en t bu t a somewhat g r e a t e r i n s u g a r s . These two c o n s t i t u e n t s a re u s u a l l y grouped t o g e t h e r as c a r b o h y d r a t e s , when c o n s i d e r i n g human o r a n ima l n u t r i t i o n . Due, however , t o the p reponderance o f s t a r c h i n the d r y ma t t e r o f p o t a t o e s , and t he c o m p a r a t i v e l y s m a l l amounts o f s u g a r s , the c a r bohyd r a t e range i n the samples was a l s o s m a l l . Range i n ash con t en t was f ound t o be na r r ow , w i t h p r o t e i n v a r i a t i o n s some-what g r e a t e r . I t wou ld seem t h e r e f o r e , as f a r as these ana l y s e s show, t h a t t h e r e was l i t t l e t o choose between the v a r i o u s f e r -t i l i z e r t r e a tmen t s i n t h e i r e f f e c t s on these c o n s t i t u e n t s . F u r t h e r t e s t s made i n c o n n e c t i o n w i t h e f f e c t s o f the f e r t i l i z e r s on n u t r i t i v e q u a l i t y i n c l u d e d : ( I ) M i n e r a l a na l y s e s 53 (2) E l e c t r i c a l r e s i s t a n c e o f the j u i c e , and (3) T i t r a t a b l e a c i d i t y . I n t h i s r e g a r d i t was found t h a t none o f the f e r t i l i z -e r s p roduced any samples e s p e c i a l l y h i g h e r t han o t he r s i n m i n -e r a l s , e x c e p t i n g t h a t the l a t e a p p l i c a t i o n o f ammonium s u l f a t e and the check p l o t s p roduced po t a t o e s somewhat l ower t han most o f the o t h e r s i n f o u r o f the m i n e r a l s c on c e r ned . I r o n was found t o be q u i t e h i g h i n a l l samp les , compared w i t h the u s u a l f i g u r e s quoted f o r p o t a t o e s ( 2 4 ) , bu t o t h e r m i n e r a l s a re m o s t l y average o r l o w . The comple te t r ea tmen t was h i g h e s t i n g e n e r a l m i n e r a l c o n t e n t , h a v i n g the most phosphorus and i r o n . A d d i t i o n of b o r on , manganese, su l fu r^ o r gypsum to the complete f e r t i l i z -e r d i d n o t g i v e any s p e c i a l l y s i g n i f i c a n t e f f e c t s . The complete-p l u s - bo rax and c o m p l e t e - p l u s - s u l f u r do s t and c o m p a r a t i v e l y h i g h i n s t a r c h e s , s u g a r s , p r o t e i n s , and t o t a l a s h , bu t s i n c e the v a r i a t i o n s i n a l l o f t h e se a r e no t v e r y g r e a t , t h e i r s co r e s on o t h e r c o n s i d e r a t i o n s t e nd t o o f f s e t t h i s . R e s u l t s o b t a i n e d f rom the e l e c t r i c a l r e s i s t a n c e and t i t r a t a b l e a c i d i t y t e s t s were so c l o s e f o r the v a r i o u s samples as t o be o f no p r a c t i c a l u se i n i n d i c a t i n g r e l a t i v e v a l u e s o f the v a r i o u s f e r t i l i z e r t r e a t m e n t s . O the r C o n s i d e r a t i o n s i n Regard to Q u a l i t y . - To supp-lement what has a l r e a d y been s a i d , the f o l l o w i n g p o i n t s s hou l d be c o n s i d e r e d : ( I ) S o i l , and (2) C l i m a t e . Chem i ca l a n a l y s i s o f the s o i l samples r e v e a l e d e spe c -i a l l y a l a c k o f magnesium and s u l f a t e s , and t o a l e s s e r deg ree , a v a i l a b l e pho spha t e s . Magnesium was no t i n c l u d e d i n any o f the f e r t i l i z e r t r e a t m e n t s , b u t s u l f a t e s and phosphates d i d t end t o improve c o o k i n g q u a l i t y , as a l r e a d y n o t e d . N i t r a t e d e f i c i e n c i e s 54 w h i l e o c c u r r i n g , were n o t marked t o the same degree as those o f the t h r e e n u t r i e n t s a l r e a d y men t i oned , and i n p l o t s where such d e f i c i e n c i e s d i d o c c u r , n i t r o g e n f e r t i l i z e r was i n c l u d e d i n the t r e a t m e n t e No a p p r e c i a b l e e f f e c t s a re to be found i n c onne c t i o n w i t h v a r i a t i o n s i n pH r e a d i n g s , Y i e l d s a re i n some i n s t a n c e s h i g h e r a t a h i g h e r pH i n d u p l i c a t e p l o t s o f the same f e r t i l i z e r t r e a t m e n t o T h i s i s no t i n agreement w i t h the f i n d i n g s o f Smi th . ( 26 ) . M e c h a n i c a l a n a l y s i s o f the s o i l s showed them t o be v e r y , s i m i l a r i n m e c h a n i c a l c o m p o s i t i o n , and t h e r e f o r e c o u l d n o t i n t h i s r e g a r d cause d i f f e r e n c e s i n t he p o t a t o e s p roduced on them. C o n s i d e r a t i o n o f c l i m a t i c c o n d i t i o n s f o r June , J u l y , and August 1937 show t h a t as compared w i t h average c o n d i t i o n s , the p r e c i p i t a t i o n was d oub l e , the h u m i d i t y was c o n s i s t e n t l y h i g h e r , hou r s o f b r i g h t sunsh ine were c o n s i d e r a b l y l e s s , and the mean mon th l y t empera tu res s l i g h t l y h i g h e r i n June and J u l y and average f o r August ( 7 ) . Such c o n d i t i o n s may have accoun ted t o some e x t en t f o r the r e l a t i v e l y low s co r e s on c o o k i n g q u a l i t y i n a l l samp les , j u dg i n g b y the f i n d i n g s o f F i n d l a y (29) i n S c o t l a n d , who found t h a t p o t a t o e s a re more mea ly i n a d r y s e a s -on t h an when t he p r e c i p i t a t i o n i s h i g h , o r by those o f Cobb (8) , who r e c o r d s l owe r average t empera tu res as p r o du c i n g h i g h e r q u a l i t y . 55 Summary and C o n c l u s i o n s e l e A l l f e r t i l i z e r t r e a tmen t s gave h i g h e r y i e l d s t han t h a t o b t a i n e d f rom the check p l o t s , , 2. The comple te f e r t i l i z e r p roduced the g r e a t e s t y i e l d and the l a r g e s t pe r cen t age o f ma rke t ab l e t u be r s „ 3© The comp l e t e -m inu s -po t a s s i um t r ea tmen t ( ammonium s u l f a t e p l u s superphosphate ) gave a lmos t as g r e a t a y i e l d as the comp l e t e , b u t p roduced e x c e s s i v e s e cond -g row th . The com-p l e t e minus phosphorus a p p l i c a t i o n ( ammonium s u l f a t e p l u s p o t a s s i um c h l o r i d e ) a l s o p roduced a l a r g e q u a n t i t y o f s e cond -growth t u b e r s , bu t t h i s c o n d i t i o n was no t n e a r l y so marked as i n t he case o f the comp l e t e -m inus -po t a s s i um t r e a t m e n t . 4 8 P o t a s s i um c h l o r i d e a p p l i e d a l o n e , gave a c o n s i d e r a b l y i n f e r i o r y i e l d t o t h a t s e cu red by the complete t r e a t m e n t . 5 . There was l i t t l e t o choose between the v a r i o u s f e r t -i l i z e r t r e a tmen t s i n r e g a r d t o t h e i r e f f e c t s on t o t a l d r y m a t t e r , t o t a l c a r b o h y d r a t e s , s t a r c h , o r a s h , s i n c e the ranges i n a l l t hese were c o m p a r a t i v e l y n a r r o w 0 The comp l e t e , o r com-p l e t e p l u s o t h e r f e r t i l i z e r s , showed some tendency towards p r o d u c i n g h i g h e r s t a r c h . 6 . No one o f the f e r t i l i z e r t r e a tmen t s p roduced a p r o -duc t e s p e c i a l l y h i g h e r i n g e n e r a l m i n e r a l c on t en t as compared w i t h the o t h e r s . The check p l o t s and the l a t e a p p l i c a t i o n o f ammonium s u l f a t e p roduced t u b e r s l owe r than those f rom most o f the o t h e r t r e a tmen t s i n f o u r out o f the s i x m i n e r a l s d e t e r -m i ned . The comple te f e r t i l i z e r p roduced t ube r s c o m p a r a t i v e l y h i g h i n m i n e r a l s . 7 . No e s p e c i a l l y s i g n i f i c a n t r e s u l t s were o b t a i n ed f rom 56 a d d i t i o n o f b o r a x , manganese s u l f a t e , s u l f u r , o r gypsum, t o the comple te t r e a t m e n t , 8 C None o f t he c o o k i n g s co r e s were h i g h . Abnormal weather c o n d i t i o n s may have been a c o n t r i b u t i n g f a c t o r h e r e . 9 , The two h i g h e s t c o o k i n g s co r e s were f o r t u be r s p r oduc -ed f rom p l o t s where o n l y s u l f a t e s were a p p l i e d . • 10 , D i f f e r e n c e s i n c o o k i n g s co r e s were v e r y l a r g e l y due t o v a r i a t i o n s i n m e a l i n e s s , a l t h ough s t a r c h v a r i e d l i t t l e , 1 1 , I r o n was q u i t e h i g h i n a l l samp les ; o t h e r m i n e r a l s were e i t h e r average o r l ow , 12 , Sugars were above a ve r age , t o t a l d r y m a t t e r a l i t t l e be low a ve r age , and s t a r c h , p r o t e i n , and ash were be low a ve r age , 1 3 , There were no s t r o n g l y marked c o r r e l a t i o n s , e i t h e r p o s i t i v e o r n e g a t i v e , i n the r e s u l t s , b u t t he r e were a number o f genera3. t e nden c i e s f o r c e r t a i n q u a l i t i e s t o be a s s o c i a t e d ; i n some cases these were o n l y s l i g h t . They were as f o l l o w s : (a) H i gh y i e l d and low d r y m a t t e r , (b) H i gh c o o k i n g s co re and h i g h d r y m a t t e r , , ( c ) H i gh c o o k i n g s co re and h i g h s p e c i f i c g r a v i t y , (d) H i gh c o o k i n g s co re and h i g h s t a r c h . (e) H i gh c o o k i n g s co r e and low s u g a r . ( f ) H i g h c o o k i n g s co r e and low p r o t e i n . (g) H i g h c o o k i n g s co re and low a s h . 14 , When b o t h y i e l d and g e n e r a l q u a l i t y a re c o n s i d e r e d the complete f e r t i l i z e r t r ea tmen t gave the most s a t i s f a c t o r y r e s u l t s . 57 ACKNOWLEDGEMENTS, The w r i t e r w i shes e s p e c i a l l y t o exp res s h i s thanks t o D r . G ,H . H a r r i s , A s s o c i a t e P r o f e s s o r o f H o r t i c u l t u r e , under whose d i r e c t i o n t he i n v e s t i g a t i o n was c a r r i e d ou t , f o r sugges t i n g t he p r o j e c t , and f o r h i s v e r y h e l p f u l c r i t i c i s m s and sup -e r v i s i o n a t a l l times® Thanks are also due t o D r , A . P , B a r s s , head o f the Department o f H o r t i c u l t u r e , f o r h i s i n t e r e s t and s ugge s t i o n s d u r i n g the e n t i r e cou r se o f the work . 58 L i t e r a t u r e C i t e d , (1) A g r i c u l t u r a l S t a t i s t i c s R e p o r t , B .C . Dep t , o f A g r , R e p o r t , 1937, (2) - A s s o c i a t i o n o f O f f i c i a l A g r i c u l t u r a l Chem i s t s , Methods o f A n a l y s i s , Wash ing ton , D.C. 1935, (3) A t k e s o n , P,W• and Ande r son , G .C . Po t a t oe s as a Peed f o r D a i r y Cows, U n i v . o f Idaho A g r . E x p t . S t a , B u i , 216, 1935, (4) B e w e l l , E . R . The D e t e r m i n a t i o n o f the Cook ing Q u a l i t y o f P o t a t o e s , Amer, P o t a t o J o u r . 14: 235 . Aug . 1937, (5) B l a c k , P.C* P o t a t o -G r ow i ng i n B r i t i s h Co l umb i a , (Manures and F e r t i l i z e r s ) , B .C . Dep t , o f A g r . B u i , 8 6 . 1933 . (6) C h i l d , A . M . and Lynch , M.C. A S tudy o f the Ba k i ng and B o i l i n g Q u a l i t i e s o f P o t a t o Tubers Grown under D i f f -e r en t C o n d i t i o n s o f S o i l . J o u r . Home E con . 20: 754 , 1928. (7) C l i m a t e o f B r i t i s h Co l umb i a . B .C . Dep t , of A g r . R epo r t , 1937, (8) Cobb, J . S . A S tudy o f C u l i n a r y Q u a l i t y i n Whi te P o t a t o e s , Amer, P o t a t o J o u r . 12: 335 . 1935 . (9) Day, E .D . The E f f e c t o f Cook ing on C e l l u l o s e , J o u r , Home E con , I : 177 . 1909, (10) G o l d t h w a i t e , N .E . V a r i a t i o n s i n the Compos i t i on o f C o l -orado P o t a t o e s . C o l o , A g r . E x p t . S t a . B u i , 296 . 1925 . (11) Hantke , A.W. Coteked Po t a t oe s B l a c k en Because B e t t e r Crops w i t h P l a n t Pood , Amer. Po t a sh I n s t , I n c . 21: 1 2 . A u g . - S e p t . 1938. 59 (12) H a r r i s , G .H . Ra spbe r r y N u t r i t i o n , I I I , A re S u l f a t e s De-f i c i e n t i n B .C . C o a s t a l S o i l s ? S c i , A g r e 17: 7 07 . J u l y 1937 , (13) H i l l , H, M i no r E lements A f f e c t i n g H o r t i c u l t u r a l C r o p s . S c i , A g r , 17: 148 . November 1936, (14) Hubbard , P . L . Methods o f Chem i ca l A n a l y s i s , U n i v , o f C a l , 1923 , (15) K imbrough, W.D. E f f e c t o f F e r t i l i z e r Treatment on the Y i e l d , Q u a l i t y , and Keep i ng Q u a l i t i e s o f I r i s h P o t -a t o e s . P r o c . Amer, Soc , H o r t . S c i . 28: 256 . 1931 . (16) Lamot t e -Mo rganc S o i l T e s t i n g S e t , Lamotte Chem i ca l P r o -duc t s Co , B a l t i m o r e , Md. (17) Longmore, R ,H . E f f e c t s o f S o i l Types on the Cook ing Q u a l i t y o f P o t a t o e s . B 6 S 0 A . E s s ay , Dep t , o f H o r t . U n i v . o f B .C . 1937. (18) Morgan, M.F . The U n i v e r s a l S o i l T e s t i n g Sys tem, Conn, , A g r , E x p t . S t a . B u i , 372 , 1935 . (19) P a r k s , F.W. and Fudge , J . F o S o i l S c i . 24: 109 - 117 , (20) R a t h l e f , H. v o n . The F l e s h Co l o u r o f the P o t a t o , Amer, P o t a t o J o u r . I I : 180, 1934, (21) R e g u l a t i o n s , R e g u l a t i o n s Co ve r i n g F r u i t and V e g e t a b l e s , B .C . Dep t . o f A g r , 1937. (22) R e p o r t . Repo r t o f the Nor thwest F e r t i l i z e r Confe rence o f H o r t i c u l t u r i s t s . Wash. S t a t e C o l l e g e . 1938, (23) R i c h a r d and W e l l s . Amer. J o u r , o f Chem. 27: 459 . (24) Sherman, H.C. Chem i s t r y o f Food and N u t r i t i o n . T h i r d E d i t i o n , 1928 . 60 (25) S h u t t , F . T . and W r i g h t , L . E . Manures and F e r t i l i z e r s . Bom, of Can . Dep t . o f A g r , B u l e 145 - New Series, 1931 . (26) Sm i t h , 0 . Growth and Development of the P o t a t o as I n f l u -enced E s p e c i a l l y by S o i l Reac t ion , , C o r n e l l U n i v . A g r , E x p t , S t a , Memoir 215 , June 1938 , (27) Sm i t h , 0 , and Nash L . B e E f f e c t o f C e r t a i n M ino r E lements on Chem i c a l Compos i t i o n and Cook ing Q u a l i t y of P o t -a t o Tube r s . P r o c Amer, Soc , H o r t . S c i . 35: 530 1937 , (28) Spurway, C H . S o i l T e s t i n g , M i c h , A g r , E x p t , S t a . Te ch . BVLT% 132 . Rev . Oc tobe r 1935, (29) Sweetman, M.D. F a c t o r s A f f e c t i n g the Cook ing Q u a l i t y o f P o t a t o e s . Ma ine A g r . E x p t . S t a . B u i . 383 . J u l y 1936* (30) T i c e , C. P o t a t o - G r o w i n g i n B r i t i s h Co l umb i a , B .C. Dep t . Of A g r . Bule 8 6 , 1933 . (31) Tu cke r , J . Canad ian C e r t i f i e d Seed P o t a t o e s . Dom. o f Can . Dep t , o f A g r . Pam. 129 - New S e r i e s , I 9 3 I „ (32) Ware, L .M , and K imbrough, W*D. I n f l u e n c e o f D i f f e r e n t F e r t i l i z e r T rea tments on C e r t a i n C h a r a c t e r i s t i c s o f the I r i s h P o t a t o c P r o c . Amer. S o c , H o r t . S c i . 30: 4 85 . I933« (33) 'Whi t temore, M. and Buschke , B .M . C e r t a i n R e l a t i o n s h i p s o f P o t a s h F e r t i l i z a t i o n and V a r i e t i e s o f P o t a t o e s to Tab l e V a l u e . R . I „ A g r , Expt*, S t a . B u i . 231 . 1932, (34) Z a v i t z , C .A . Pota toes- , On t . Dep t . A g r , B u i * 239 . May 1 9 1 6 . 4 APPENDIX'. TABLE*15 . 6 1 P l o t | Y i e l d ( l b s . p e r a c , ) ^Sa l e ab l e I 1 5 2 1 6 3 1 7 4 1 8 5 . 1 9 6 2 0 7 2 1 2 3 * 0 5 1 1 7 , 7 8 7 1 9 , 7 8 4 1 5 , 2 4 6 1 8 , , 5 1 3 1 5 , 0 6 5 2 3 g 4:14 1 6 , 7 8 0 2 2 , 6 8 8 1 5 , 7 9 1 2 0 , 5 1 0 1 7 , 0 2 1 2 2 , 3 2 5 1 6 , 0 5 4 W e 2 i © , 7 . , : V 2 © 5 7 0 . 7 5 3 © 4 G 3 © 3 „ 52©V 5 5 . 9 5 4 , 0 7 5 , 0 6 6 . 8 7 8 . 5 5 8 , 6 6 8 , 2 5 e C o Growth I I . 3 1 4 . 8 1 7 , 0 1 3 © V 2 1 , 1 2 4 . 1 3 6 , 3 3 1 « 5 2 4 . 0 1 0 . 6 1 4 . 7 1 3 , 8 2 3 , 4 1 5 , 0 $Sma l l 1 1 , 5 1 4 , 5 1 0 . 5 1 5 , 6 2 3 • 5 1 2 , 6 1 1 , 0 1 2 . 6 2 2 . 0 1 4 . 4 1 8 © 5 7 . 7 1 8 , 0 1 6 , 8 T A B L E 1 5 . 6 2 P l o t Y i e l d ( l b s , p e r a c , ) ^Sa l eab l e ^Sec.Growth ^Smal l 8 1 8 , 8 7 6 7 2 . 4 1 8 . 1 9 , 5 2 2 1 0 , 7 0 9 6 9 , 9 8 . 9 2 X Q 2 9 1 8 , 1 5 0 6 8 . 8 1 9 . 3 JL x«Q 2 3 1 3 , 7 9 5 7 1 , 1 7 . 2 2 1 . 7 1 0 1 7 , 7 8 7 6 5 . 1 1 9 . 9 1 5 . 0 2 4 1 4 , 1 5 8 6 7 , 9 5 . 8 2 6 . 3 I I 17,96.9 6 6 , 7 2 3 . 2 I © . I 2 5 1 2 , 3 4 2 . 5 6 . 2 1 8 . 7 2 5 . 1 1 2 1 5 , 2 4 6 7 3 . 5 1 4 , 6 I I . 9 2 6 1 2 , 1 6 1 6 2 . 7 1 3 . 8 2 3 ® 5 1 3 1 4 , 3 3 9 6 4 * 1 1 5 . 8 2 0 , 1 2 7 9 , 2 5 7 5 9 . 8 5 . 4 3 4 . 8 1 4 1 3 , 9 7 6 5 4 . 5 1 8 . 8 2 6 . 7 2 8 9 , 4 3 8 6 0 . 1 6 . 7 3 3 , 2 TABLE 1 5 . ( c on t i nued ) TABLE 16 63 B l o t . S p e c i f i c G r a v i t y D ry Wei g l i t M e a l i n e s s C o l o r F l a v o r ( T o t a l book ing Score I ,1 .0692 20 .38 24 16 28 68 15 I . 0 741 20 .42 16 16 22 54 2 I , 0 703 19 .83 20 14 28 62 16 I o 0 8 1 3 21 .15 30 16 28 74 3 1.0753 20 ,98 19 16 25 60 17 1,0783 21 .84 25 16 : 27 68 4 I , 0 754 20 ,95 22 16 22 60 18 1^0783 22 .63 26 16 28 70 5 I . 0 713 22 .80 18 16 23 57 19 1,0753 20 ,73 18 16 23 57 : 6 : 1.0775 21 .33 16 12 22 50 20 1,0741 21 © 23 18 12 22 52 7 I . 0 721 22 ,00 1.9 14 22 55 21 1.0756 22 , 62 19 14 24 57 .TABLE 16 64 P l o t S p e c i f i c G r a v i t y Dry Weight M e a l i n e s s C o l o r F l a v o r T o t a l Cook ing Score 8 .1*0746 21.50 21 16 28 65 22 I .0746 21 ,10 22 . 1 6 25 63 9 1,0750 21 .63 21 22 52 23 I o 0 7 5 3 22 .93 26 16 26 68 10 1,0755 21 .80 19 14 24 57 24 I e 0 7 4 5 21,22 24 16 25 65 I I 1,0746 20,58 25 16 26 67 25 1.0766 21 .62 ' 40 16 25 81 12 1.0748 20.75 21 16 26 63 26 I .0818 24 .60 39 16 26 81 13 1.0798 21.97 23 16 19 58 27 1,0848 23 .75 35 19 26 80 14 1.0798 22 © 2o 26 16 25 67 28 1.0850 24 © 1*7 28 16 31 75 TABLE 16 . ( c on t i nued ) 1 TABLE 1 7 • 65 P l o t ^Reduc ing Sugars ^ T o t a l Sugars ^S t a r ch ^ P r o t e i n ^To t a l Ash I 0*41 0 .69 16 .55 1.398 0 .886 15 0.27 0 .29 16 .25 1.674 0.807 2 0 ,38 r ' 0 . 48 16 .24 1,374 0 ,820 16 0 ,32 0 .38 , 17 .02 1,689 0 .662 3 0 .42 0 .51 ., 16 .92 1.383 0„720 17 0 .33 0 . 40 16 ,14 1.745 0 .822 4 0 ,44 0 , 6 7 16 .02 1.776 0.796 18 0 .46 0 .71 16 .48 1.987 0 .689 5 0 , 2 8 0 ,71 16*08 1.627 0 .862 19 0 . 5 5 0 .76 I 6 i 9 6 1,706 0 .683 6 0 .66 0 .98 ; 16 ,33 1.999 0 ,739 20 0 ,66 0 .90 15 .95 2.028 0 .639 7 0 .59 0 ©83 16 .37 2.215 0 .764 21 0 .55 . 0 . 6 9 16 ,75 2,239 0.716 TABLE 1 7 . 66 P l o t % Reduc i ng Sugars % T o t a l Sugars •% S t a r c h % P r o t e i n % T o t a l Ash 8' 1 0,63 0 ,84 16 .13 1.659 0 .823 22 0 ,45 0 .64 16.47 1.675 0.629 9 0 ,61 0,86 16 ,70 1.973 0.786 23 0,57 0 .65 17.30 18,594 0 .747 10 0 ,49 0 .63 I 6 0 4 3 1,654 0,986 24 0 .44 0 ,74 16 ,61 1.379 0.749 I I 0 .44 0 ,52 15.26 1.385 0.799 25 0,46 0 .68 15,46 2.055 0.839 12 0 .52 0 .70 16 .21 1,851 0,652 26 0 ,71 1,04 16 ,10 2,092 0,734 13 0 .49 0 ,64 16 « 28 1.858 0 .697 27 0 .59 0 .74 16^.10 • 1.702 0.736 14 0,57 0 .74 15.99 1.466 0.848 28 0 ,62 0 .81 16 .81 1.907 0.813 • TABLE 1 7 , ( c o n t i n u e d ) T A B L E 1 8 , 67 P l o t K Ca Mg P C l Fe E l e c t r i c a r R e s i s t a n c e (ohms) T F l t r a t a h l e A c i d i t y ( c c s . O . I / N NaOH) I 222 6 ,5 9 . 1 ' 57 .7 3 7 . 4 1.3 106 .4 29 © 5 . 15 280 5.9 29 . 2 45 .6 35 @ 2 1.9 102 .9 34 . 0 2 345 6 .7 7 , 5 40 e7 28 , 7 I ® 2 108 ,5 30 . 5 16 219 9 .7 9 . 2 48 . 8 70.5; 1.0 95 ,9 34 . 0 3. , 389 8 . 2 10 . 2 35 ,7 <37.9 I . I 9 9 , 4 35 ,0 17 239 8 . 6 ; 29 ,6 20 6 5 2 4 . X : T i l • 102 .9 35 .0 4 200' 7 .5 8 .6 4 9 . 4 37.2 I . I 102 .9 35 o 5 18 218 ; 5.0 27 .0 45,1 27 .7 I . I - 112 .7 36 . 5 5 211 5.7 10 .6 55 © 5 46 ,6 0 . 9 112 ,7 37 .5 19 208 5 © 3 59 .8 20 . 0 6 5 , 1 1,3 105 .0 28 .5 6 255 6 .4 8 ©8 4 7 . 2 4 7 . 1 0 .6 105 .0 36 .5 20 218 6 .5 23 © 0 19 ,6 4 0 . 3 I . I 107 , 1 25 ,5 7 104 4 , 8 14 ,6 67 ©I 36 ,7 0 .2 95 ,9 39 .0 21 229 E4.3 8 . 0 3 0 . 1 41 , 9 1.0 108 ,5 35 , 0 TABLE 1 8 , 68 ' l o t : K Ca Mg P 01 Fe E l e c W r c a T " R e s i s t a n c e (ohms) ~ TT t ra tabTe"— A c i d i t y ( c c s . O . l / N NaOH) 8 266 6 ,4 10 .0 71 .7 35 .0 1,0 84 .0 40 .0 22 229 6 .8 16 .4 3X $ 5 58 ,2 1*1 114 .1 32 .0 9 136 4 ,8 29 . 1 47 .7 39 .6 0 , 1 94 .5 36 .5 23 187 8 .2 26 ,2 35 © 4 43,0 X 1*1 :100.8 34 .0 10 239 5.7 12*4 59 . 0 29 .2 0 .2 85 . 4 31 .0 24 249 I I . 9 14 . 2 31 ,6 39 .8 I . I 105 ,0 32 . 0 I I 260 6 , 1 15 . 2 31 , 0 45 , 0 2^3 98 ,7 32 .5 25 208 7 . 4 30 , 8 25 ©V 32 ,2 0 .8 88 .9 33 © 5 12 260 3 .9 14 , 2 52 . 9 38 ,8 2 © 2 109 9 2 . 30 .0 26 176 9 . 5 14 ,1 20 .5 33 .4 0 .9 96 6 37 .0 13 229 4 . 2 12 ©3 44 , 5 47 . 1 1.9 100.8 36 .0 27 208 5.6 8 , 5 12 .1 35 « 5 0 .8 81 .9 42 .5 14 270 5 ,2 12 .8 49 . 5 22 o 5 0.9 87 . 5 36 .0 28 198 5.4 9 ,2 12 .7 X 9 © 9 X © 3 98.7 36 .0 TABLE 18 , ( c on t i nued ) TABLE 19o SHOWING THE RANK WHICH THE' TUBERS PROM THE VARIOUS FERTILIZER TREATMENTS SCORED IN EACH OF THE TESTS MADE. 69 F e r t i l i z e r Complete Superphos pha te K C l (NEU )*. S0 4 * K C l ( N E U ) a S 0 4 * Supe rphos -pha te K C l + ( i f f i J , P O K C l Complete + Borax Complete + •MhSO* Complete+S Complete + Gypsum (NEULSO^ ( N H 4 k SO* + FeSO* (NH 4)*SO* (Aug . I 7 ) None H © 6 7 2 3 5 I I 8 8 10 12 13 14 co Hi CO H ctf CO I 3 12 14 8 2 4 5 7 I I 10 13 •A-£ o 54 <3 •d fl o o CO co I I 6 9 10 3 8 14 12 •ri > cd o •ri « H • H O CO 14 6 5 4 13 6 12 I I 9 10 8 2 I © O S fi 14 13 8 10 6 I I 9 4 7 12 3 I -p CQ 7 2 4 10 5 13 9 I 5 14 12 I I 7 ra cd CO H cd 42 O EH 12 14 13 8 7 I 6 4 10 I I 8 4 fl • r i © O S H P4 <; H cd o EH 14 8 2 9 12 13 I I 4 I a: 10 I 5 2 14 I TO 9 I I 7 I 4 3 13 6 12 TABLE 1 9 e Showing the rank which the'tubers from the various f e r t i l -i z e r treatments scored i n each of the tests made. 70 F e r t i l i z e r Potassium 1 • • :  4 Calcium Magnesium Phosphorus • 1 j Chlorine Iron Electrical Conductivity titratable Acidity Jooking Score Complete. 3 I I 5 I 9 I I I - 12 10 Superpho sphat e + KCI 2 : 4 14 6 2 5 8 I I 5 (NH J^SQtfKC l I. 3 4 14 12 5 7 7 7 (NHJ^SO^* Superphosphate 12 10 6 4 I I c o 13 3 6 KCI + (NHj^PO^ I I 12 8 I ..' 5 14 9 12 KCI , 6 8 7 10 4 I I 12 14 14 Complete + Borax 13 I I I 3 7 13 8 2 13 Complete + MnSO .^ 4 7 10 2 3 10 6 3 7 Complete+S 14 8 I Y 5 •, 13 5 6 I I Complete + Gypsum 5 2 9 5 13 12 4 13 Q (HH4),S04 7 5 3 12 8' 2 3 9 I ( N H 4 ) x S 0 4 * FeSO^ 9 6 8 9 10 2 10 8 2 ( N H j a SO*. (Aug.17) 9 14 13 13 6 • 4 I I 4 None 7 13 12 I I 14 5 2 3 3 TABLE 1 9 . ( c o n t i n u e d ) Showing the r ank wh i ch the t ube r s f rom the v a r i o u s f e r t i l i z e r t r e a tmen t s s c o r ed i n each o f the t e s t s made. VI C o n s t i t u e n t • 1 2 3 Water 7o 77 , 23 7° 78 .37 D ry M a t t e r 22,77 21 .63 T o t a l Ca rbo -h y d r a t e s T8'*4 19.79 F i b r e ... - - - - - - 0 , 3 - 0 . 6 S t a r c h I I . 3 5 - 2 1 . 8 1 16,31 Reduc i ng Sugars 0.497 T o t a l Sugars ------ 0.685* P r o t e i n 2,02 1.757 T o t a l Ash - - - - - 0.955 0.766 Po t a s s i um 0 .429 \ • 0 . 302 -1 .110 0 .231 Phosphorus 0 .058 0 .007 -0 .043 0.040 .. C h l o r i n e 0 ,038 0 .039 Magnesium 0.028 ,0.017 Sodium 0 ,021 . - — ' Ca l c i um 0,014 0.007 I r o n 0 ,0013 • - 0 .011 TABLE 20, : AVERAGE COMPOSITION OF POTATOES, Column one g i v e s f i g u r e s as quoted by Sherman ( 2 4 ) . Quota -t i o n s i n co lumn two a re from those g i v en by Sweetman ( 29 ) , G o l d t h w a i t e 1 s f i g u r e s f o r t h i n l y - p e e l e d , i r r i g a t e d t ube r s b e -i n g t a k e n , where a v a i l a b l e . Column th r ee shows the r e s u l t s ob -t a i n e d by the w r i t e r , u s i n g e n t i r e p o t a t o e s . A l l f i g u r e s g i v e n a re p e r c e n t a g e s . 

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