|ADHIKARI, PRADIP - Oklahoma State University|
|ALE, SRINIVASULU - Texas A&M University|
|DELAUNE, PAUL - Texas A&M University|
|BARNES, ED - Cotton, Inc|
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2017
Publication Date: 12/20/2017
Citation: Adhikari, P., Ale, S., Delaune, P.B., Thorp, K.R., Barnes, E.M. 2017. Simulated effects of winter wheat cover crop on the cotton production systems of the Texas rolling plains. Transactions of the ASABE. 60(6):2083-2096.
Interpretive Summary: Winter cover crops can help to build soil health in the cotton production regions of the west Texas Rolling Plains. However, the effects of the winter cover crop on the productivity of the subsequent cotton crop are unclear. In this study, a crop simulation model was used to compare the soil moisture conditions and cotton yield for production systems that did and did not include a winter wheat cover crop. Simulations were also conducted for both irrigated and dryland cotton production. Based on five years of simulated data, the results showed that winter wheat cover crops had no significant effect on soil water status and yield of the following cotton crop. The results are useful for agronomists and cotton growers in the west Texas Rolling Plains, who aim to increase soil conservation without sacrificing the productivity of existing crop management techniques.
Technical Abstract: There has been an increasing interest to grow cover crops in the Texas Rolling Plains (TRP) region, mainly to build soil health. However, there are concerns that cover crops could potentially reduce soil water, and thereby affect subsequent cash crop yield. Previous field studies from this region demonstrated mixed results with some showing a reduction in cash crop yields due to growing of cover crops and others indicating no significant impact of cover crops on subsequent cotton fiber yields. The objectives of this study were: (i) to evaluate the CROPGRO-Cotton and CERES-Wheat modules within the Cropping System Model (CSM) of the Decision Support System for Agrotechnology Transfer (DSSAT) for the TRP region, and (ii) use the evaluated model for assessing the long-term effects of growing winter wheat as a cover crop on water balances and seed cotton yield under irrigated and dryland conditions. The above two modules were calibrated using the measured data on soil moisture and crop yield from four treatments: (i) irrigated cotton without a cover crop (CwoC-I) (ii) irrigated cotton with winter wheat as a cover crop (CWC-I) (iii) dryland cotton without a cover crop (CwoC-D) and (iv) dryland cotton with a winter wheat cover crop (CWC-D) at the Texas A&M AgriLife Research Station at Chillicothe during the period from 2011 to 2015. The degree of agreement (d) between the CROPGRO-Cotton simulated and measured seed cotton yield was 0.93 and 0.95 during the calibration and validation periods, respectively, and the coefficient of determination (r2) was 0.99 during calibration and 0.97 during validation. In case of above ground biomass prediction by the CERES-Wheat model, d and r2 were 0.91 and 0.76, respectively, during the calibration period, and 0.90 and 0.68, respectively, during the validation period. Results from the long-term (2001-2015) simulations indicated that there was no statistically significant reduction in seed cotton yield and soil water due to growing of winter wheat as a cover crop.