Profit‐Maximizing Irrigation for Cotton on High Available Water Holding Capacity Soils

Abstract

To improve irrigation management in the midsouthern United States, information is needed on the effects of irrigation on high available water holding capacity (AWHC) soils under humid, short‐growing season conditions. The objective of this research was to determine the effects of irrigation timing on lint yield, quality, and profit‐maximizing irrigation rates for cotton (Gossypium hirsutum L.) production in such an environment on high AWHC soils. Lint yield and quality data were collected during a 2006 to 2009 cotton irrigation experiment at Jackson, TN. Lint yield and adjusted price responses to total water (rainfall plus irrigation) were estimated as quadratic functions when irrigation was initiated at first square, first bloom, and mid‐bloom. The baseline rainfall scenario showed that the profit‐maximizing irrigation rate was 94 mm with lint yield of 1893 kg ha−1 and net returns of US$2051 ha−1 when irrigation was initiated at first square. For irrigation initiated at first bloom, the profit‐maximizing irrigation rate increased to 121 mm with lint yield of 2052 kg ha−1 and net returns of $2213 ha−1. Profit maximizing irrigation rate was 173 mm with lint yield of 2174 kg ha−1 and net returns of $2361 ha−1 when irrigation was initiated at mid‐bloom. Initiation of irrigation at mid‐bloom would maximize profits on high AWHC soils given the results of this research. However, there are some years in Tennessee when irrigating cotton will not increase expected net returns due to sufficient rainfall or insufficient heat‐unit accumulation to fully mature the crop.Core Ideas Determine the effects of irrigation timing on yield and profit maximizing irrigation rates for cotton production in humid short‐growing season on high available water holding capacity soils. Initiation of irrigation at mid‐bloom would maximize profits on high available water holding capacity soils given the results and costs described from this research. Baseline rainfall scenario shows that profit‐maximizing net return was US, 051, 213, and, 361 ha−1 when irrigation was initiated at first square, first bloom, and mid‐bloom, respectively.