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.