Cotton Production As Affected by Irrigation Level and Transitioning Tillage Systems in the Texas Rolling Plains.

Identifying management practices that conserve and protect water resources are very important to a wide variety of stakeholders within semi-arid environments. The objective of this study was to develop water management strategies for transitioning tillage systems in cotton production (Gossypium hirsutum) within the Texas Rolling Plains when in a subsurface drip irrigation (SDI) system. Five irrigation regimes (0, 33, 66, 100, and 133% evapotranspiration (ET) replacement) and four tillage systems (conventional till, reduced till, no-till, and no-till with a terminated cover crop) were evaluated.  The study was conducted for three years and treatments were replicated three times in a randomized complete block design.  Lint yields were not affected by the main effects of tillage or the interaction of tillage and ET replacement. In contrast, ET replacement was a significant factor for lint yields, irrigation water use efficiency, and net returns. Greatest lint yields and net returns were achieved at 100% ET replacement.  Fitted models indicated that optimum lint yields and net returns were achieved at 104.5% ET and 102% ET, respectively.  Irrigation at 83% ET was within the 95% confidence interval for lint yield.  Net returns were significantly higher for no-till systems compared with conventional till.  Thus, adoption of conservation tillage systems should not negatively affect lint yield or net returns in deficit irrigated SDI cotton systems within the Texas Rolling Plains, particularly during the transition from intensively tilled systems to conservation tilled systems.