|Unger, Paul - USDA-ARS (RETIRED)|
|Stewart, B - WEST TEXAS A&M UNIV.|
Submitted to: China International Conference on Dryland and Water-Saving Farming
Publication Type: Proceedings
Publication Acceptance Date: October 20, 2000
Publication Date: N/A
Technical Abstract: Fallow using stubble-mulch (sweep till) or no-tillage (chemical weed control) residue management is an effective method to increase soil water storage. As a result, dryland grain sorghum [Sorghum bicolor (L.) Moench] and winter wheat (Triticum aestivum L.) yields are increased by using the wheat-sorghum-fallow (WSF) rotation with an intervening fallow to produce two crops in three years. Our objective was to document the impact of residue management practices in the semiarid southern Great Plains on dryland water use and yields of grain sorghum and winter wheat in a long-term study. Wheat and sorghum were grown in rotation on six contour-farmed terraced watersheds so that each WSF phase appeared every year. For both tillage systems, we compared crop yields and harvest index, and plant available soil water content at planting and harvesting (for seasonal water use). Long-term mean grain yields for sorghum and wheat were eabout 4.00 and 1.90 Mg/ha for no-tillage compared to about 3.20 Mg/ha and 1.80 Mg/ha for stubble-mulch. For the WSF rotation on the semiarid southern Great Plains, no-tillage after wheat increased soil water storage > 30 mm compared to stubble mulch, and a mean dryland sorghum yield about 19 kg/mm available soil water at planting.