Investigating SDI Design, Installation, and Management Practices for Improved Row Crop Production in the Texas South Plains: A 15 Year Review of Research
The Southern High Plains of Texas is a semi-arid, irrigated area having rapidly declining water tables. Over the past 15 years, experiments at the Texas A and M AgriLife Research Center in Halfway, Texas have been conducted using subsurface drip irrigation (SDI) in efforts to improve water productivity and irrigation cost efficiencies in cotton production. Field evaluations from 2001 to 2006 showed cotton lint yields were not significantly reduced by lowering water distribution uniformities in SDI treatments where coefficients of variation (Qvar) ranged from 5% to 27%. In experiments from 2006 to 2010, traditionally installed SDI laterals between pairs of 0.76-m spaced cotton rows resulted in slightly higher cotton lint yields than rows spaced at 1.02 m using identical irrigation amounts. When considering perpendicularly crossing 1.52-m spaced laterals with 0.76-m wide crop rows, only modest declines in cotton lint yield occurred compared to traditional parallel row-lateral orientation having the same lateral and row spacing. In experiments from 2009 to 2012, four-year cotton lint yields, seasonal irrigation water use efficiencies, and cotton lint loan values of treatments having 7-d irrigation intervals were equal to or, in some cases, significantly greater than the 0.25- and 1-d irrigation interval treatments. Ongoing experiments initiated in 2013 evaluated combinations of cotton row/lateral position and planting date as they relate to germination, yield, and initial SDI costs. Experiments involving the design, installation and management of SDI have helped overcome barriers to wider SDI adoption in the Texas South Plains.