Relationships between plant and soil nutrient status and position in the landscape on Pellic Vertisols of Ethiopia

Abstract

Effects of land use on soil nutrients and related soil parameters of Pellic Vertisols were assessed using soil samples collected from plots subjected to the cultivation of tef (Eragrostis tef) (TF) and grass pea (Lathyrus sativus) (GP) and native grassland subjected to year-round (continuous) grazing (CG) and seasonal grazing (SG). Soil under grassland had significantly (P<0.01) higher clay, organic matter (OM), total N and extractable Fe contents than cultivated soil. The opposite was noted for pH and sand content. TF cultivated plots had a significantly (P<0.05) higher extractable P content. Land use did not affect the cation exchange capacity (CEC) and exchangeable cations, but Fe, Cu and Zn levels differed (P<0.05) between land use types. Soil pH was positively correlated (P<0.01) with exchangeable Ca in soil under TF, GP and SG grassland. In all land uses, OM was positively (P<0.05) correlated with total N and negatively (P<0.05) correlated with exchangeable Ca. Except in CG grassland, CEC was positively (P<0.05) correlated with exchangeable Ca. It was concluded that land use affects the physico-chemical properties of Vertisols, but the present status of soil nutrients, with the exception of P, might not limit crop and pasture production.