Characterizing Water Use Under Different Tillage and Water Management Strategies for Grain Sorghum Production.

In the semi-arid regions of West Texas water is the most limiting factor for crop production. Strategies and practices that enhance productivity are critical. Optimizing tillage systems with efficient irrigation systems for best practice synergies can enhance production. Water use efficiency can be improved by augmenting the efficiency of irrigation systems. This study was conducted to characterize soil water at different irrigation rates using three tillage systems under subsurface drip irrigation. The experiment was a randomized complete block design with three tillage treatments and three replicates. Tillage treatments were Conventional till, No-till and Strip till. The levels of water application were 0, 30, 60 and 90% of evapotransipiration (ET) in an Abilene clay loam soil under subsurface drip irrigation. Access tubes were placed in every treatment next to sorghum row to a depth of 150cm. A neutron probe was used to measure soil water storage once every two weeks at 20cm depth increments beginning at the 10 cm depth and continuing to a depth of 130 cm in each tube. The neutron probe readings were converted to volumetric soil water content with three calibration equations determined at the experimental site. The mean stored soil profile water was greater in no-tillage most of the season compared to conventional tillage although water use efficiency was significantly (P<0.05) highest in conventional tillage at ET replacements 60% and 90%. Water use efficiency increased with ET replacement from 0% through 30% to 60% and decreased at 90% across tillage systems. No significant differences on grain yields were observed between 60 and 90% ET replacement levels.