A Study of The Application of Phosphorous to Potential Paddy Soils of The Accra Plains And Its Interaction With Other Plants Nutrients

ABSTRACT

A g r e e n h o u s e p o t e x p e r i m e n t w a s s e t up t o f i n d the effect of added p h o sp h o ru s on the ava ilability and u p t a k e o f P s M n a n d F e b y r i c e p l a n t u n d e r f l o o d e d conditions. Two soil s e r ie s Akuse and Amo (verti« sol and Inceptisol, re sp ectiv ely ) were used. The e x p e r i m e n t was of a s i m p l e f a c t o r i a l d e s i g n c o m p r i ­ sing of four l e v e l s of P with and without r i c e p l an t on both soils under continuous submergence. Samples of growing ric e p l a n t s , s u p e r n a t a n t soil solution, and the wet soils were taken for laboratory analysis at one, two, three, five, six and eight weeks of age during an eight week p e r i o d . The soluble P , Mn and Fe in the su p e r n atan t liq u id s , the uptake of these ions by the plant and the extractable Mn and Fe from the wet soil were determined, I n m o s t of t h e t r e a t m e n t s , P a M n a n d F e f o l l o w e d s i m il a r trends in both cropped and uncropped so ils. In the m a j o r i t y of the t r e a t m e n t s , the highest values of n u tr ie n ts were obtained in the f i r s t week with m a r k ­ ed dec re a se in the second or third week after t r a n s - V p l a n t i n g / s u b m e r g e n c e . In the c a s e of iron in the plant m a te r ia l, the marked d e c r e a s e was in the fifth w e e k . The c o n c e n t r a t i o n of the n u t r i e n t s in the treatm ents generally decreased to about the lo w e st level in the eighth week ex c e p t Mn and Fe in the wet soil tre a tm e n ts and Fe in the plant m aterial which increased then. C hanges in a v a ila b ility may have been due to r e d u c t i o n or o x i d a t i o n of p h o s p h a t e c o m p o u n d s of Mn and F e, s o l u b i l i t y or p r e c i p i t a t i o n of Ca p h o s ­ p h a t e , h y d r o l y s i s , or c o m p l e x fo rm in g t e n d e n c i e s of Fe and Mn, r e s u l t i n g in a v a i l a b i l i t y or p r e c i p i ­ t a t i o n o f P , M n a n d o r F e w h i c h i n t u r n s o m e t i m e s affected the uptake by the p lant. The two soils studied were found to be s i g n i ­ f i c a n t l y d i f f e r e n t in r e l e a s e of the n u t r i e n t s under study as a f f e c te d by the a d d i t i o n of tr ip le s u p e r ­ phosphate fertilizer. These differences were r e fle c ­ t e d i n t h e  y i e l d  o f   the  ric e crop  n w h i c h A m o s e r i e s did much better than Akuse serie s.