Irrigation Scheduling in Cotton Using the MU Crop Water Use App

The MU Crop Water Use (CWU) App provides a way for farmers to schedule irrigations in a variety of crops. One variable that the app depends on is the rooting depth of your crop. At the MU-Lee Farm, cotton plots were irrigated based on CWU root depth settings of 6, 12, 18, 24, and 30 inches to validate the proper rooting depth trigger for cotton. Actual rooting depth in plots were measured with an endoscope. Irrigating too early or often reduced cotton yields. The highest seed cotton yields occurred when irrigations were triggered using the 18 inch rooting depth in the app.  The endoscope showed that cotton roots continued to grow deeper throughout the growing season.  Cotton roots were found 40 inches from the surface in late August. However, the efficiency of those lower roots to hydrate the crop was not sufficient to optimize yield.