Crop production in semi-arid dry land areas of Ethiopia is totally dependent on erratic rainfall-uneven in distribution, torrential in intensity, low in amount during crop growing season and variable from year to year. This result unpredictable agricultural production and occasional crop failure. Therefore, the study was designed to evaluate the effect of in-situ moisture conservation techniques such as tied ridge and mulch and planting methods on soil moisture content, yield and biomass of sorghum during 2006 cropping season. Factorial combinations of treatments were laid out in randomized complete block design with three replications. The results of the experiment indicated that the main effect of planting methods and mulches were highly significant (p<0.01) in influencing the grain and biomass yield. Irrespective of planting methods, there were 77.1% and 59.2% advantage of grain and biomass yield due to tied-ridge over the control. Furthermore, sorghum planted in furrows and on top of ridges increased grain yield in the order of 98.3% and 41.6% and biomass yield by 68.5% and 35.7% over flat planting method, respectively. A grain yield increase of 25.9% and 14.4% and biomass yield increase of 23.1% and 18.9% was obtained by applying 6 and 3 t/ha of mulch over the bare plot, respectively. In case of soil moisture content dynamics, highest volumetric soil water content (VSWC) was obtained from the tied-ridges, followed by open ridges over the flat tillage. VSWC was significantly greater under furrow planting and lowest in flatbed method. Like wise, soil surface covered with 3 and 6 t/ha mulch levels gave higher VSWC over no mulch treatment. Therefore, the result indicates that in areas such as Alamata, tied ridge with furrow planting and application of 6 t/h mulch were the most preferable soil moisture conservation technique and planting method for increasing grain and biomass yield of sorghum.

Keywords: In-situ moisture conservation; Soil moisture content; Tied ridge; Mulch; Planting method; Sorghum