Effectiveness of cattle manure and nitrogen fertilizer application on the agronomic and economic performance of maize
South African Journal of Plant and Soil
Department of Soil Science and Agricultural Engineering, University of Zimbabwe, P.O. Box MP 167, Mount Pleasant, Harare, Zimbabwe; Department of Agricultural Economics and Extension, University of Zimbabwe, P.O. Box MP 167, Mount Pleasant, Harare, Zimbabwe; Plant Production Systems, Department of Plant Sciences, Wageningen University, P.O. Box 430, 6700 AK Wageningen, Netherlands
The effects of N fertilizer and aerobically composted cattle manure, applied separately or in combination, on maize (Zea mays L.) grain yields and net benefits were determined over three seasons. A field experiment was established on a moderately leached sandy loam soil (Typic Kandiustalf). Manure was a poor source of N. In the first year, increase in grain yield was much higher when manure (12.5 t ha-1 and 37.5 t ha-1) was combined with the 60 kg N ha-1 mineral N rate (40% and 25.1%, respectively), and a relatively smaller further increase of 17.5% was recorded for the 37.5 t ha-1 rate while there was a decrease of 3.7% for the 12.5 t ha-1 rate, when mineral N rate was doubled to 120 kg N ha-1. In the third season increase in grain yield was also much higher when manure (12.5 t ha-1 and 37.5 t ha-1) was combined with the 60 kg N ha-1 mineral N rate (66.2% and 16%, respectively) and relatively smaller further increases were recorded when the mineral N rate was doubled to 120 kg N ha-1 (21.4% and 15.1%, respectively). Net benefit indications are that residual effects of cattle manure last for at least three seasons and thus farmers could apply up to 40 t ha-1 in the first season and benefit from its residual fertility in subsequent seasons. It was concluded that smallholder farmers in Zimbabwe and other countries of Sub-Saharan Africa could positively exploit the combined application of manure and N fertilizer to increase maize yield and net benefits.
agricultural economics; fertilizer application; manure; nitrogen; yield; Africa; Eastern Hemisphere; Southern Africa; Sub-Saharan Africa; World; Zimbabwe