Furrow Irrigation Termination Timing Effects on Southwest Oklahoma Cotton

A majority of the acreage in the Lugert-Altus Irrigation District is furrow irrigated with water from Lake Lugert. Generally, about 3 to 4 acre-inches per irrigation is applied using gravity flow through a concrete ditch/siphon tube system.  Typical furrow irrigation termination in the area is around September 1.  Due to variable inflow in the watershed in some years, questions have been asked concerning the long-term impact of earlier irrigation termination.  Is there a potential water savings without sacrificing yield and quality?  A multi-year project was established in 2015 and continued in 2016 and 2017.  The objectives of this project were to evaluate the effects of 3 weekly irrigation termination timings in furrow irrigated cotton.  Target termination dates of August 16, August 23 and August 30 were used.  A randomized complete block design with three replications was used.  Nodes above white flower and nodes above cracked boll were obtained to assess crop maturity effects.  WaterMark sensor data for 10, 20 and 30 inch depths were collected weekly.  Ultimately, the impact on yield and HVI and AFIS fiber quality was determined.