Measuring and simulating maize (Zea mays L.) yield responses to reduced tillage and mulching under semi-arid conditions

Abstract

Rainfed smallholder agriculture in semi-arid environments of sub-Saharan Africa faces many challenges. Productivity of the smallholder ag-ricultural systems has been on the decline in recent years. Conservation agriculture practices have a potential of steering the smallholder agri-cultural systems of sub-Saharan Africa to grea-ter and more sustainable levels. This study was designed to calibrate the APSIM model so that it could be used as a tool for understanding the long term impact of conservation agriculture techniques (mulching, tine ripping and planting basins) on the productivity of smallholder sys-tems under semi-arid conditions. The APSIM model predicted reasonably well the seasonal and mulching effects on maize production on sand and clay soils. Under these semi-arid conditions the use of 10 kg·N·ha –1 is preferable under both conventional and basin tillage sys-tems. Planting basins offer a better chance of getting maize grain yield than the conventional system in southern Zimbabwe at N quantities ranging from 0 kg·ha –1 to 52 kg·ha –1 . This mod-elling exercise suggested that smallholder farmers are still prone to complete crop failure in some years despite the use of available con-servation agriculture systems.