Influence of planting basins on selected soil quality parameters and sorghum yield along an agro-ecological gradient in South Eastern Zimbabwe
Planting basins are an important soil and water conservation technology. This study evaluated the effects of basins on soil organic carbon (SOC) stocks, aggregate stability (Ima), bulk density, soil moisture retention and sorghum yield in agro-ecological regions III, IV and V of Chipinge district. The experiment consisted of three treatments; namely planting basins (basins) with goat manure and inorganic fertilizer application, hand hoeing with similar fertility amendments (FP+) and hand hoeing without fertility amendments (FP). It was hypothesized that planting basins with fertility amendments would improve the selected soil quality parameters and sorghum yield. Only planting basins significantly (p˂0.05) improved soil quality parameters in the 0-15 cm depth and bulk density, Ima, SOC stocks ranged from 1356 to 1451 kg/m3; 314 to 450 and 14.18 to 25.55 Mg ha-1 respectively. Planting basins significantly increased (p<0.05) sorghum yield relative to hand-hoeing practices (FP+ and FP) with average grain yield of 2.68, 1.72 and 1.32 t ha-1 in agro-ecological regions III, IV and V, respectively. When compared to FP+ and FP, basins increased grain yield by >130% in all the 3 agro-ecological regions. The hypothesis was accepted and it was concluded that basins improve soil properties and sorghum grain yield in agro-ecological regions III, IV and V. Considering the soil and crop productivity benefits highlighted in this study, there is a strong justification for the widespread promotion and adoption of planting basins in semi-arid agro-ecological regions of Zimbabwe.