Soil nutrient accumulation under traditional African agriculture in the miombo woodland of Zambia

Abstract

Four types of agricultural systems in Zambia were investigated for their influence on soil fertility. Two types of wood-ash fertilizer-based shifting cultivation systems were shown to mobilize P, even in deeper horizons, immediately after burning; the changes in cation exchange capacity and amounts of exchangeable macronutrients were most felt in the upper part of the profile. Mound cultivation concentrated soil nutrients of the topsoil with significant effect. K and P concentrations were slightly lower than under ash-fertilization, but CEC values were even higher. As an alternative to mound and ash-cultivation, compost-dependent systems were shown to accumulate nutrients effectively; after four years of legume-cereal crop rotation on mounds alternating with flat-cultivation, more nutrients accumulated in the soil of the mound than were present before the fallow.