Tillage and Subsurface Drip Irrigation Effects On Runoff, Sediment, and Nutrient Losses Under Simulated Rainfall.

Within semi-arid regions such as the Texas Rolling Plains, water is the most limiting factor in crop production.  Hence, tillage and irrigation systems play an important role in water capture, water use efficiency, and subsequently conservation of soil and water resources.  The objective of this research is to evaluate runoff, sediment, and nutrient losses from tillage systems in cotton production with and without subsurface drip irrigation.   Three tillage systems (conventional-till, no-till, and no-till with a terminated cover crop) and three irrigation regimes (0, 66, and 133% ET replacement) will be evaluated.  The tillage and irrigation treatments have been in place for two complete growing seasons.  Rainfall simulators were used to provide a 70 cm hr^-1 storm event sufficient to produce 30 min of continuous runoff. Runoff water was collected and weighed to determine runoff volume.  Composited samples were analyzed for total solids, TKN, TP, and dissolved P.