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 (1.7 mm day1) in the St. Lawrence region of West Texas. Two frequency intervals werestudied during two years; these intervals were 4 and 16 days in 1999 and 2 and 8 days in 2000. Each treatment was replicatedfour times, and the total amount of water applied each year was the same. The soil was a silty clay loam soil underlain bycaliche just below 90 cm from the surface. In both years, there were no significant differences between frequency treatmentsin lint yield, micronaire, fiber length, fiber strength, uniformity, or gross returns. Using the loan values as an indicator of lintquality, cotton loan values were highly significant in 1999, but were not different in 2000. With no major advantage inincreasing irrigation frequency using SDI under deficit conditions, these results may have an impact on the agronomicpractices of the region where water is very limited. Low frequency irrigation may allow farmers to have more flexibility inmanaging their irrigation systems and avoid the additional expense of automating a microirrigation system.