Tillage practice effects on yield of maize under smallholder cropping in Malawi

A field study was undertaken on an Oxic Rhodustalf to compare the effects of three tillage practices on germination and yield of maize (Zea mays L.) over the 1993-94 and 1994-95 crop growing seasons. Tillage practices consisted of making ridges every year by concentrating the topsoil (0-20 cm) in a defined region (conventional tillage), tilling only a small planting zone on the previous year's ridges (zone tillage), and making small mounds of soil in the furrows (mini-mound tillage). Germination and grain yield of maize were not significantly (P > 0.05) affected by tillage practices. The average grain yields over the two seasons were 4444 +/- 190, 4367 +/- 98, and 4515 +/- 139 kg ha(-1) for conventional, zone, and mini-mound practices, respectively. However, both zone and mini-mound tillage practices were associated with remarkable reduction in working time and labour requirement compared with conventional practice. These results suggest that some modified tillage practices could provide useful alternatives to the conventional annual ridging currently recommended by extension services in Malawi.