Irrigation Termination for Improved Cotton Fiber Maturity.

Preliminary studies were initiated at the Texas Agricultural Experiment Station in Halfway in 2007 in a field site with sub surface drip irrigation.  The sub surface drip irrigation system is sub divided into 9 zones with each zone being approximately 0.5 ac.  The main plot treatments were timing of irrigation termination and the sub plot treatments were cultivar. Irrigation termination treatments were (1) Nodes Above White Flower = 5, (2) Nodes Above White Flower = 5 + 2 weeks and, (3) First Cracked Boll.  Preliminary results indicate irrigation termination treatments were too early as lint yield was reduced with earlier termination timings.  Interestingly, fiber fineness decreased and immature fiber content increased with later irrigation termination timings while the maturity ratio decreased.  These results indicate fiber maturity may be improved with earlier irrigation termination.  Also, mean fiber length decreased and short fiber content increased with later termination treatments while the fiber length coefficient of variation increased.  These results may also be related to fiber maturity as more immature fibers may also be more prone to breakage, resulting in reduced fiber length and fiber length uniformity.