NAHUNTA, NORTH CAROLINA
Given the variability of weather conditions that impact the Southeast throughout the year, researchers at North Carolina State University have been studying the impacts of water capture and reuse for irrigation for cotton production throughout the region.
With funding from Cotton Incorporated, Dr. Mohamed Youssef, Professor of Biological and Agricultural Engineering at NCSU, and his team were able to investigate crop yield and improvements to water quality of on-farm water capture and use.
The initial research was conducted at the Peanut Belt Research Station in Bertie County, North Carolina. The data collected was used to obtain a three-year Federal Conservation Innovation Grant awarded by the U.S. Department of Agriculture. The study was conducted from 2022 until 2024. The research findings and implications from this project could be applicable to cotton producers across the Southeast.
How WCR Systems Work
Before diving into the research, I thought it would be beneficial to describe a typical on-farm water capture and reuse system. A WCR system captures and stores surface runoff water and subsurface drainage water in on-farm ponds or reservoirs during wet periods of the year. It is then used for supplemental irrigation during dry periods of the crop growing season.
These types of systems can vary in size and layout, based on your operation. They typically include an irrigation system, drainage area and an on-farm pond or reservoir.
Three-year Study Results
Cotton yield data were measured as part of this study over the three-year period. Each of the three growing seasons were distinct: one with near optimal rainfall (2022); one with very dry conditions (2023); and one with a very wet spell during the second half of July (2024).
The water-related conditions were clearly reflected in the cotton yield response. The 2022 season had near ideal rainfall conditions in July and August. Both irrigated and non-irrigated fields had relatively high lint yield with no need for additional irrigation.
During the 2023 season, severe dry conditions occurred during July 1 and August 15. The research demonstrated that supplemental irrigation was extremely effective in alleviating stresses due to dry conditions, resulting in a substantial increase in lint and seed yields. The 2023 season illustrated the value irrigation can bring as irrigation increased yield by over 600 pounds that season.
The third season in the study, 2024, was characterized by wet conditions between mid-July and mid-August, which hurt the plant during flowering and boll formation phases. This depressed the yield for both irrigated and non-irrigated fields. In 2024, supplemental irrigation was not needed.
Yield And Water Quality
Water quality benefits of on-farm WCR were also experimentally investigated at two research sites with water storage ponds of different sizes.
The data shows that water storage ponds are effective in treating agricultural runoff and reducing the nutrients and sediment that are leaving the farm and reaching the receiving surface water bodies.
It was found that the treatment efficiency depends on the average length of time the captured water stays in the pond before it is discharged to downstream water.
“This study has done an excellent job illustrating the benefits of on-farm water storage with improvements in yield and water quality leaving the pond,” said Dr. Youssef. “I expect the effect of supplemental irrigation to vary from year-to-year depending on weather conditions related to precipitation and temperature.
“It is important to remember that implementing these practices can be beneficial to growers but during some years, they may not increase yield at all in North Carolina.”
Further Benefits
By funding research that explores practices like on-farm water capture and reuse, Cotton Incorporated empowers producers to adapt to increasingly unpredictable weather patterns. This research not only demonstrates the potential for improving yields through supplemental irrigation but also highlights the broader environmental benefits, such as enhanced water quality and flood mitigation.
These insights are invaluable in equipping growers with tools to navigate challenges while ensuring the long-term sustainability of cotton farming in the Southeast.