Conservation tillage with animal draught in Zambia

The Golden Valley Agricultural Research Trust (GART) investigates the possibilities for the introduction of conservation tillage to small farmers in the (semi-arid) central and southern provinces of Zambia. Major emphasis is given to the implementation of conservation tillage by using animal drawn rippers, as an alternative to conventional mouldboard ploughing. This simple technology has already proven (by on-station research and on-farm adaptive trials) to be quite successful in being able to establish a good crop stand while requiring little energy. It may provide the best opportunity to reduce the negative effects of drought, and thus improve food security and protect the agricultural base from further degradation. Crops are maize, cotton, sunflower and soybean. Results of this work will be presented with regard to operational (time and energy consumption) and agronomical aspects (soil structure, water availability, crop establishment, yields and weeds). Various tillage systems are being assessed and compared: shallow ripping by oxen, deep (15-25 cm) ripping by oxen, ploughing using a common ox-drawn mouldboard plough, ridging after deep ripping (all by oxen), manual hoe or stick planting, manual preparation of basins. Energy input was by far the lowest in shallow ripping, followed by deep ripping. These operations can be carried out rapidly and timely (even before the onset of the rains). The most intensive tillage treatments (mouldboard ploughing, ridging) showed higher yields and caused the lowest weed pressure. In the very dry season 2001-2002, however, crops on ripped fields had a higher survival rate than on conventionally tilled fields.