Effects of nitrogen rate and cover crop on cotton (Gossypium hirsutum L.) yield and soil water content

Authors: Sui, Ruixiu; Anapalli, Saseendran

Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2021
Publication Date: 7/10/2021
Citation: Sui, R., Anapalli, S.S. 2021. Effects of nitrogen rate and cover crop on cotton (Gossypium hirsutum L.) yield and soil water content. Agriculture. 11(7):650. https://doi.org/10.3390/agriculture11070650.
DOI: https://doi.org/10.3390/agriculture11070650

Interpretive Summary: Nitrogen (N) fertilization in cotton has a critical effect on cotton yield. In cotton production, understanding the crop response to N-rate is necessary for optimal N use efficiency. Cover crops can improve soil water infiltration and reduce runoff losses. ARS researchers in Stoneville, MS studied the response of cotton yield and soil water content to N application rates and tillage radish cover crop (TRCC) in the Mississippi Delta. They found that the TRCC increased soil water infiltration capacity and retained more soil water. Increasing N rate from 84 to 140 kg ha-1 could possibly increase cotton yield but needs further investigations to confirm. Influence of TRCC on cotton yield was not significant at this location, which could be caused by poor growth of the cover crop from cold temperatures and excessive winter rains. TRCC should be planted no later than middle of October in this region to allow the plant to be well developed prior to the cold winter weather for its optimum regrowth in the subsequent spring. Results of this study provided useful information for adopting TRCC in cotton production in the Mississippi Delta.

Technical Abstract: Judicial use of cover crops can improve soil health in cotton production systems im-pacting cotton productivity positively. Simultaneously, appropriate use of nitrogen fertilizer (N) is also crucial for optimizing cotton production. The objective of this study was to test the effects of N rates and a winter tillage radish (Raphanus sativus L.) cover crop (TRCC) on soil water and lint yield in irrigated cotton (Gossypium hirsutum L) in the Mississippi Delta (MD) region. The ex-periments were conducted in three years (2017-2019), randomized in twelve 183m x 23m farm-strip scale plots in a silt loam soil. The treatments were N rates at 84 kg ha-1 and 140 kg ha-1 with and without TRCC. Irrigations were scheduled based on in-situ sensor-measured soil water contents and applied using a center-pivot irrigation system. Soil volumetric water content was measured using soil water sensors. Cotton lint yields were not significantly (p>0.05) influenced by the winter cover crop. Compared to N rate at 84 kg ha-1, 140 kg N ha-1 increased lint yield, but the increase was statistically significant only in 2019 (p<0.02). Interactions between cover crop and nitrogen rate on lint yield were significant (p<0.03) only in 2017. Increasing N rate from 84 to 140 kg ha-1 could increase lint cotton yield in the MD region. TRCC increased soil water infiltration capacity and resulting in higher soil water content. Use of the winter cover crop did not affect cotton yield in this study, which could be due to the high inputs of water (rainfall and irrigations) and high rates of N neutralizing the positive contributions to cotton growth expected from the cover crops in these aspects in the trials. Sub-optimum winter temperatures hampered establishment and subsequent growth of cover crops, which also possibly contributed to its minimum impacts on cotton crop performance in the following season.