Effects of Cropping Practices on Water-Use and Water Productivity of Dryland Winter Wheat in the High Plains Ecoregion of Wyoming

The conventionally tilled winter wheat (Triticum aestivum L.)-fallow system is often water-use inefficient as its fallow phase has frequently less storage efficiency than no-till and organic production practices. While such alternatives may increase yield while enhancing the health and the water holding capacity of soils, the major limiting factor for dryland production in the semi-arid regions is water. The objectives of this study were to a) determine the water-use and water productivity of dryland winter wheat under conventional, no-till, and organic production practices, and b) study the impact of improved soil-water storage on no-till winter wheat yield. A field experiment consisting of three tillage practices with three replicates was conducted at the University of Wyoming Sustainable Agricultural Research and Extension Center, near Lingle, Wyoming, USA. The wheat yield was higher in the conventional practice than in the other two production practices, and water-use in the former system was higher than the no-till. Water productivity of dryland winter wheat was not affected by the cropping practices. The CERES-Wheat model in the Decision Support System for Agrotechnology Transfer (DSSAT) was used to simulate long-term effects of no-till and conventional-till cropping practices for yield, water conservation, and water productivity. The simulations showed a good agreement between the observed and simulated crop yield and more efficient water conservation and yield production in the no-till than in the conventional practice.