Location: Water Management and Conservation Research
Title: Determining optimum irrigation termination periods for cotton production in the Texas High PlainsAuthor
ALE, SRINIVASULU - Texas A&M University | |
OMANI, NINA - Syngenta | |
HIMANSHU, SUSHIL - Texas A&M University | |
BORDOVSKY, JAMES - Texas A&M University | |
Thorp, Kelly | |
BARNES, EDWARD - Cotton, Inc |
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/16/2019 Publication Date: 1/15/2020 Publication URL: https://handle.nal.usda.gov/10113/6933556 Citation: Ale, S., Omani, N., Himanshu, S.K., Bordovsky, J.P., Thorp, K.R., Barnes, E.M. 2020. Determining optimum irrigation termination periods for cotton production in the Texas High Plains. Transactions of the ASABE. 63(1):105-115. https://doi.org/10.13031/trans.13483. DOI: https://doi.org/10.13031/trans.13483 Interpretive Summary: Cotton production in the Texas High Plains (THP) region relies heavily on irrigation using groundwater from the underlying Ogallala Aquifer. Rapidly declining groundwater levels in the aquifer and increasing pumping costs pose challenges for sustainability of irrigated cotton production in this region. The objective of this study was to calculate optimum irrigation termination periods for cotton production in the THP under full and deficit irrigation conditions using a modern crop simulation tool. Eight irrigation termination dates with a one-week interval between 15 August and 30 September were simulated, and impacts on cotton water use and seed cotton yield were calculated. Optimum irrigation termination periods for cotton were found to be the first and second week of September in years with normal precipitation. In wet and dry years, optimum irrigation termination periods were a week earlier and later, respectively than for normal years. The results from this study will assist cotton producers in the THP to make appropriate decisions on irrigation termination, thereby extending the usable lifetime of the Ogallala Aquifer and ensuring water security for agriculture in the future. Technical Abstract: Cotton (Gossypium hirsutum, L) production in the Texas High Plains (THP) region relies heavily on irrigation with groundwater from the underlying Ogallala Aquifer. However, rapidly declining groundwater levels in the aquifer and increasing pumping costs pose challenges for sustainability of irrigated cotton production in this region. Adoption of efficient irrigation strategies such as terminating irrigation at an appropriate time could enable producers in the THP region to increase irrigation water use efficiency (IWUE) while maintaining desired yield goals. The objective of this study was to determine optimum irrigation termination periods for cotton production in the THP under full and deficit irrigation conditions using the Decision Support System for Agrotechnology Transfer (DSSAT) CROPGRO-Cotton model, which was evaluated in a prior study using measured data from an IWUE field experiment at Halfway in the THP. The treatment factors in the experiment included irrigation capacity of 0 mm d-1, Low (L); 3.2 mm d-1, Medium (M); and 6.4 mm d-1, High (H), applied during three growth stages: pre-bloom, peak bloom and post peak bloom. This study focused on a full irrigation (HHH) and three deficit irrigation (LMH, LHM and LMM) treatments. Eight irrigation termination dates with a one-week interval between 15 August and 30 September were simulated, and the impact of irrigation termination date on cotton IWUE and seed cotton yield were studied by dividing the 39-yr (1978 to 2016) simulation period into i) dry, ii) normal and iii) wet years based on the precipitation received from 1 April to the simulated irrigation termination date. Results indicated that the simulated IWUE was consistently higher under LHM, LMH and LMM treatments when compared to the HHH treatment. Based on the simulated average seed cotton yield and IWUE, optimum irrigation termination periods for cotton were found to be the first week of September in case of HHH and LMH treatments, and the second week of September in case of LHM and LMM treatments in normal years. In wet/dry years, optimum irrigation termination periods were a week earlier/later than those in normal years for HHH, LHM and LMM treatments. In case of LMH treatment, the optimum irrigation termination period in wet years was the same as that in normal years and a couple of weeks later in dry years. The results from this study will assist cotton producers in the THP to make appropriate decisions on irrigation termination, thereby extending the usable lifetime of the Ogallala Aquifer and ensuring water security for agriculture in the future. |