Micro-basin tillage for grain sorghum production in semiarid areas of northern Ethiopia

The yield of grain sorghum (Sorghum bicolor L. Moench) and other crops is often constrained by soil water deficits in semiarid areas of Ethiopia. The effectiveness of micro-basin tillage, in the form of tied-ridging, was evaluated as a means of improving soil water availability through reduced runoff and to increase grain and stover yield. Field research was conducted on a clay soil with vertic properties (Typic Pellustert) in northern Ethiopia in 2003 and 2004. Tied-ridging conducted before planting, at planting, and after planting was compared with planting on a flat soil surface without ridging and with a traditional ridging practice known as shilshalo. Planting in-furrow was compared with planting on-ridge. Tied-ridging before or at planting resulted in the best soil water status throughout the season and the best crop performance, especially when planting was in-furrow. Mean soil water content with the most effective tied-ridge treatment was on average 42% and 49% more than with flat tillage and planting in 2003 and 2004, respectively. Overall crop performance was generally worst for flat soil surface planting and for the shilshalo treatment, where the respective grain yield was 45% and 62% of yield with in-furrow planting, respectively. Soil water availability in the 0- to 0.90-m soil depth dropped below the permanent wilting point for all treatments before the grain was physiologically mature. Yield can be increased by tied-ridging before or at planting. The results indicate that mean yield can be improved by planting with the onset of the rains.