Twenty Years of Nitrogen Management Research for Texas and Arizona Cotton: What We Have Learned

This is an overview of 20 years of N management research for irrigated cotton in West Texas and Arizona.  Deep pre-plant soil nitrate test as well as canopy reflectance-based N management are the key components.  An algorithm is excel was developed that uses the pre-plant soil nitrate data and a yield goal to make N fertilizer recommendations.  Additionally, timing, mode of application, and enhanced efficiency fertilizers were tested.  Irrigation systems employed were furrow, overhead sprinkler and subsurface drip irrigation.  Nitrogen balances, Nitrogen-15 isotopes and nitrous oxide emissions were also studied.