Evaporation from Soil as Affected by Incorporation and Surface and Subsurface Placement of Oat Straw

A study was conducted in columns with black and red soils of similar texture to compare the effectiveness of various residue management treatments for moisture conservation. Cumulative evaporation was higher from red soil, although cumulative potential and initial evaporation were more from the black one. After 40 days, the maximum reduction in water loss (23.7%) resulted from sub-surface placement of oat straw @ 7 tlha, followed by the treatment involving its application on the surface, incorporation into surface soil and tillage alone, wherein the evaporation was reduced by 16.0, 12.8 and 5.5% respectively, over control. In another experiment, at the end of five wetting and drying cycles, where additional water was applied whenever control soil columns lost approximately 40%_o of the water held at field capacity, evaporation was reduced with sub-surface placement, surface placement and mixing of straw by 42.0, 33.4 and 28.3% respectively. The effect of the treatments was markedly reflected in moisture distribution along the soil depth measured at different intervals.