Maize (Zea mays) yield and its relationship to soil properties under integrated fertility, mulch and tillage management in urban agriculture

Abstract

Urban agriculture improves people’s livelihoods in developing countries. An experiment was carried out to assess effects of soil fertility, mulch and tillage on soil organic carbon (SOC), aggregate stability (Ima), bulk density (BD), steady state infiltration rate (SSIR) and maize yield. Cattle manure (CM) + mineral N fertilizer, 0 or 5 t ha−1 mulch and reduced tillage (RT) or conventional tillage (CT) treatments were imposed on sandy and red clay soils in Harare. After two cropping seasons, soil samples were taken from 0–5, 5–15 and 15–30 cm depths and SSIR was measured on site. RT significantly improved (p < 0.01) SOC and Ima in the 0–5 cm depth by at least 6% over CT. SOC and Ima increased by at least 13% under CM + mineral N fertilizer compared with sole mineral fertilizer. CM + mineral N fertilizer increased SSIR by at least 17% over sole mineral fertilizer, whilst mulching improved SSIR by at least 8% and RT by 27% in both soils. Maize yields significantly increased (p < 0.05) by at least 3.7 times in both soils under mineral fertilizer. Principal component analyses showed that yield could be predicted using BD on sandy soils and Ima and SSIR on red clay soils.