COMPARISON OF NO-TILLAGE AND CONVENTIONAL TILLAGE IN THE DEVELOPMENT OF SUSTAINABLE FARMING SYSTEMS IN THE SEMIARID TROPICS

The results of 5 short-term (4-8 years) experiments and farm demonstra tions in which no-tillage technology was compared with conventional or reduced tillage in the semi-arid tropics of the Northern Territory an d Far North Queensland, during the mid 1980s to mid 1990s, are reviewe d. In the Douglas-Daly and Katherine districts of the Northern Territo ry, dryland crops of maize, sorghum, soybean and mungbean sown using n o-tillage with adequate vegetative mulch on the soil surface have prod uced yields comparable with, or higher than (especially in drier years ), those obtained under conventional tillage. The importance of a surf ace mulch in ameliorating soil temperature, moisture and fertility, an d in reducing soil movement and loss in crop production in the semi-ar id tropics was confirmed. Management of mulch (pasture, crop residues and weeds) will be crucial in the application of no-tillage technology to the development of mixed dryland crop and livestock enterprises in the semi-arid tropics.