Assessing the effects of a winter wheat cover crop on soil water use, cotton yield, crop water productivity, and soil organic carbon in no-till cotton production systems.

Authors: HIMANSHU, SUSHIL - Texas A&M Agrilife; ALE, SRINIVASULU - Texas A&M Agrilife; DELAUNE, PAUL - Texas A&M Agrilife; SINGH, JASDEEP - Texas A&M Agrilife; Mauget, Steven; BARNES, EDWARD - Cotton, Inc

Submitted to: Journal of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/11/2022
Publication Date: 10/7/2022
Citation: Himanshu, S.K., Ale, S., Delaune, P.B., Singh, J., Mauget, S.A., Barnes, E.M. 2022. Assessing the effects of a winter wheat cover crop on soil water use, cotton yield, crop water productivity, and soil organic carbon in no-till cotton production systems. Journal of the ASABE. 65(5). https://doi.org/10.13031/ja.15181.
DOI: https://doi.org/10.13031/ja.15181

Interpretive Summary: In the Texas Rolling Plains (TRP) winter cover crops can improve soil properties and reduce wind erosion, but can also reduce the soil moisture needed to produce cash crops such as cotton. To test the benefits and costs of winter cover crops, scientists from Texas A&M University and Lubbock ARS used crop models to simulate the effects of a of a winter wheat – cotton crop rotation based on TRP weather data during 2001-2021. These crop simulations showed that although winter wheat substantially reduced soil moisture during winter and early spring, soil water was quickly replenished by spring rainfall and was maintained at higher levels during the summer growing season. The winter wheat cover crop showed the potential to improve soil organic carbon in both irrigated and dryland crop simulations, but only improved soil nitrogen under dryland conditions. These results suggest that winter TRP cover crops can potentially improve soil health, while also providing a sustainable environment for TRP cotton production.

Technical Abstract: Cover crops provide many soil health benefits to agricultural systems. An interest to grow cover crops in cotton (Gossypium hirsutum L.) production systems has been increasing in the Texas Rolling Plains (TRP) region. However, due to limited rainfall and groundwater availability, producers in this semi-arid region are concerned that winter cover crops can reduce soil water availability for a subsequent cotton crop. In addition, the long-term effects of cover crops on soil organic carbon (SOC) not well studied in this region. The overall goal of this study was to assess the long-term effects of growing a winter wheat (Triticum aestivum) cover crop on soil water, SOC, seed cotton yield, and crop water productivity (CWP) under irrigated and dryland cotton production systems using the Decision Support System for Agrotechnology Transfer (DSSAT) model. Measured data from cover crop experiments conducted at the Texas A&M AgriLife Research Station at Chillicothe from 2011 to 2020 were used to evaluate the CROPGRO-Cotton and CERES-Wheat modules in the DSSAT Cropping System Model. The average percent error (PE) between the simulated and measured seed cotton yield was 0.3% and -0.9%, and that between the simulated and measured aboveground wheat biomass was 1.4% and -3.4% during the calibration and evaluation periods, respectively. For the simulation of SOC, the PE was 8.5% and 7.6% during the calibration and evaluation periods, respectively. Long-term (2001-2020) simulations showed that soil water was reduced substantially by winter wheat cover crop before its termination. However, depleted soil water was quickly replenished by spring precipitation and maintained at a higher level during the cotton growing season. Winter wheat cover crops can potentially improve SOC in irrigated and dryland cotton production systems. The CWP of cotton also improved with a winter wheat cover crop under both irrigated and dryland conditions. We concluded that cover crops could potentially improve soil health and provide a sustainable environment for TRP cotton production.