Study Of The Effect Of Successive Cropping's Of Organic Phosphorus Content Of A Selected Ghanaian Soil Using Four Different Crops

Abstract

Phosphorus does occur both in organic and inorganic forms, and a*, relatively large amount is present in organic foraf* Relatively little work has been done on organic phosphorus in Ghanaian soils. Some research workers notably Schollemberger (1920), Dean (1938) and a number of others have found that soils high in organic matte* are also high: in organic phosphorus. Bye and Bertheux (1957) working on Ghanaian soils observed considerably more organic phosphorus in forest soils than in savanna soils. There is much controversy on the form in which phosphorus is taken up by the plant* It is a general belief that organic phosphorus is utilised by the plant only when it is changed into inorganic orthophosphate form* When organic matter decomposes, the free orthophosphate ions released into the soil solution are either taken up by the plant or combine with other soil constituents'. Therefore the organic phosphorus serves as a reserve upon which the plant falls when the inorganic phosphorus present in the soil' solution is depleted. Ibwever, there is the opinion that the organic phosphorus in the soil can be directly utilised by plants without it being converted first into inorganic form and some workers have tried to establish this fact. Bottomley (1919), Heck and Whiting (1927) and many others conducted numerous studies on the availability of different organic l&osphorus; compounds to determine whether the compounds were directly 2 absorbed by -fcLants. Roger et al_(l940) fognd that both pihytin. and lecithin were absorbed directly from nutrient solutions by com and tomato plants. Pierre and Parker (1927) however, failed to find evidence of absorption of water soluble organic phosphorus of soils by corn, soybeans or buckwheat