Effects of Nitrogen Rate and Cover Crop on Cotton (Gossypium hirsutum L.) Yield and Soil Water Content

The objective of this study was to test the effects of N rates and tillage radish (Raphanus sativus var. longipinnatus) cover crop (TRCC) on soil water and cotton (Gossypium hirsutum L.) yield. In three years of the investigation, the treatments were N rates at 84 kg ha(-1) and 140 kg ha(-1) with and without TRCC. Soil water contents were measured using soil water sensors. Results showed that cotton yield was not significantly (p > 0.05) influenced by TRCC. Compared to N rate at 84 kg ha(-1), 140 kg N ha(-1) increased lint yield by 2.0%, 7.4%, 18.4% in 2017, 2018, and 2019, respectively, but the increase was significant only in 2019 (p < 0.02). Interactions between TRCC and nitrogen rate on yield were significant (p < 0.03) only in 2017. TRCC increased soil water infiltration capacity, resulting in higher soil water content. Use of TRCC did not affect the cotton yield, which could be due to the high inputs of water and high rates of N neutralizing the positive contributions to the cotton growth expected from the TRCC. Sub-optimum winter temperatures hampered the establishment and subsequent growth of TRCC, which also possibly contributed to its minimum impacts on cotton crop performance in the following season.