A model study has suggested appropriate irrigation management strategies to sustain cotton production under different weather conditions while conserving valuable groundwater resources.
- The study was conducted by the Texas A&M AgriLife Research Center at Halfway, US. The result was a report— ‘Evaluation of growth-stage-based variable deficit irrigation strategies for cotton production in the Texas High Plains’—recently published in the Agricultural Water Management journal.
The Team: The research scientists included Srinivasulu Ale, AgriLife Research agrohydrologist at the Texas A&M AgriLife Research and Extension Center at Vernon and the Department of Biological and Agricultural Engineering. Ale was joined by his former postdoc Sushil Himanshu, and current postdoc Sayantan Samanta, AgriLife Research, Vernon.
- Also on the team were Jourdan Bell, Texas A&M AgriLife Extension Service agronomist, Amarillo; Jim Bordovsky, retired AgriLife Research agricultural engineer, Halfway; and former postdoc Yubing Fan.
- The US Department of Agriculture Agricultural Research Service laboratory at Lubbock was represented by Dennis Gitz, and Robert Lascano, and at Bushland by David Brauer.
The study: The study simulated four irrigation deficit levels in four cotton growth stages, resulting in 256 scenarios.
- The goal was to identify efficient growth-stage-based variable deficit-irrigation, GS-VDI, strategies based on data from cotton irrigation water-use efficiency field experiments.
- Based on the results of simulated seed cotton yield and irrigation water-use efficiency, the study concluded that different efficient GS-VDI strategies should be considered for dry, normal and wet years.
- For example, a strategy of 90% evapotranspiration-replacement from first leaf to peak bloom and of 30% evapotranspiration-replacement in the final stage was found to be an ideal strategy in normal precipitation years to achieve higher seed cotton yield while saving 2.56 inches of irrigation water.
- By adopting GS-VDI strategies, a substantial amount of irrigation water can be saved, and it is possible to achieve high seed cotton yields with less irrigation water. In fact, the amount of irrigation water required to achieve maximum irrigation water-use efficiency was less than the amount of irrigation water required to achieve maximum seed cotton yield under all weather conditions.
- The results indicated that the extent and timing of water deficit stress in different cotton growth stages substantially affected seed cotton yield, irrigation water use and water-use efficiency.
- The results from this study could be useful for producers in the Texas High Plains region in optimising the application of limited available irrigation water to achieve higher irrigation water-use efficiency and cotton yields.
- Producers can go into a normal cotton season with a strategy of 70% deficit in the fourth stage and 10% deficit in the remaining stages.
- Future efforts of the study will focus on simulating the effects of GS-VDI strategies at different sites across the High Plains region to strengthen the recommendations.
