Effect of land use on some soil chemical properties and P fractions in south-western Nigeria

Land use directly or indirectly affects the soil chemical properties and phosphorus fractions. Two different land use types were studied. Soil chemical analysis and phosphorus fractionation of the soils was then done and the results were highly significant (p<0.001). Total C, N and P were low under the arable land use as compared to the tree crop while exchangeable Ca and Mg was higher under the arable land use than in the tree crop farmland. Micronutrients were generally low irrespective of the land use. The loosely bound P i.e. saloid bound P was more under arable farmland as compared to the tree crop farmland while there was more residual P in the tree crop farmland than the arable farmland. A positive relationship existed between the soil chemical properties and P fractions under the arable land use but a negative relationship was observed between the soil chemical properties and P fractions under the tree crop land use. In other words, cultivation as practiced in on arable lands significantly increased the labile P fractions as evident in increase in the loosely bound P and the secondary nutrients while P tends to be bound i.e. residual P in soils cropped with trees and rich in the macronutrients. . Although, irrespective of the land use type,an equilibrium reaction existed between the readily and non-readily available P fractionsin order to increase P in soils and make the essential macronutrients available, it is recommended that the land be cultivated.Keywords: Soil phosphorus, P fractions, soil chemical parameters, arable land use, tree crop land us