Cotton response to subsurface drip irrigation frequency under deficit irrigation

Cotton lint yield and quality were investigated for different irrigation frequencies using subsurface drip irrigation (SDI) under limited water conditions (1.7mm day(-1)) in the St. Lawrence region of West Texas. Two frequency intervals were studied during two years; these intervals were 4 and 16 days in 1999 and 2 and 8 days in 2000. Each treatment was replicated four times, and the total amount of water applied each year was the same. The soil was a silty clay loam soil underlain by caliche just below 90 cm from the surface. In both years, there were no significant differences between frequency treatments in lint yield, micronaire, fiber length, fiber strength, uniformity, or gross returns. Using the loan values as an indicator of lint quality, cotton loan values were highly significant in 1999, but were not different in 2000. With no major advantage in increasing irrigation frequency using SDI under deficit conditions, these results may have an impact on the agronomic practices of the region where water is very limited. Low frequency irrigation may allow farmers to have more flexibility in managing their irrigation systems and avoid the additional expense of automating a microirrigation system.