Effect of Subsurface Drip Irrigation System Uniformity on Cotton Production in the Texas High Plains

Planned reductions in subsurface drip irrigation (SDI) system uniformity in the semi-arid environment of West Texas could reduce installation costs. A SDI system was installed and cotton production experiment conducted from 2001 to 2006 to evaluate irrigation system water distribution uniformities having flow variations (Qvar) = 5%, 15%, and 27% at both moderate and near full irrigation levels. Flow variation treatments were established by installing and irrigating cotton with different diameter drip laterals in field plots in a complete block layout. Subsurface drip laterals with diameters of 17, 22, and 25 mm, pressurized at 72, 83, and 45 kPa, respectively, resulted in different irrigation uniformity treatments defined as poor (POOR), very good (VGD), and acceptable (ACC).