Impact of Tillage, Water Management, and Well Water Nitrate On Subsurface Drip Irrigated Cotton Production

The objective of this research is to develop tillage and water management strategies that enhance crop stand establishment, water-use efficiency, and yield in a subsurface drip irrigation (SDI) systems within the semi-arid Texas Rolling Plains.  Four tillage systems (conventional-till, reduced-till, no-till flat, and no-till with a terminated cover crop) and five irrigation rates (0, 33, 66, 100, and 133% ET_C replacement) were evaluated in the study.  Nitrate crediting will also be discussed, which can contribute a significant amount of N in areas that have elevated levels of nitrate in the well water.  For example, as much as 70 lbs of N was added through the irrigation system as a result of high nitrate levels in the source water.  Much of the yield data for 2009 is currently being collected and analyzed.  Acceptable plant stands were obtained in all tillage systems.  Results from the previous year showed that lint yields did not significantly increase at irrigation rates above 66% ET_C replacement and did not significantly differ among tillage systems.  An economic analysis will also be conducted to determine the most cost-effective management practices.