Nutrient management

Vertisols and soils with vertic properties are an important soil group in the Ethiopian highlands. Poor drainage, soil, water and nutrient erosion are the most serious problems on highland Vertisols. Due to their high moisture- storage capacity, they have high production potential and this potential remains underutilised because of the difficulty of managing these soils. This paper summarises available information on chemical properties, N, P and mineralogy. Literature on the P status of soils, P nutrition of forage legumes and crops, mycorrhizae and P nutrition, species and varietal variation in response to P, P sorption isotherms and P fertilisation based on forage-based cropping systems is reviewed. The review also highlights the response of various crops to N in the presence of appropriate rhizobium, microbial studies and biological nitrogen fixation and its cycling in Vertisol cropping.