THE EFFECTS OF MINIMUM TILLAGE WEEDS AND YIELD OF DURUM-WHEAT IN CENTRAL ETHIOPIA

Minimum tillage which combined reduced tillage with herbicide in the m anagement of weeds in durum wheat fields was investigated at Debre Zei t, Ethiopia for three years. The grain yield obtained from minimum til lage (MT) plots was almost 50% lower than that of conventional tillage (CT) when MT was practised continuously on the same piece of land. Ho wever, when MT was rotated with CT in alternate cycles, it was found t o be equally effective in suppressing weed populations and reducing th e dry matter accumulation of weeds. Furthermore, the grain yield diffe rence between the two treatments was non-significant. Nevertheless, a higher marginal rate of return was obtained with the use of CT. The he rbicides 2,4-D 720 amine, Brittox 52%, MCPA 625, and one hand-weeding were effective in controlling broad-leaved weeds, irrespective of the tillage system. In general, difficulty in sowing was experienced with the MT system.