Location: Delta Water Management Research
2023 Annual Report
Objectives
1. Develop improved management practices for irrigated cropping systems (e.g. rice, soybean, cotton) in humid subtropical environments.
1a. Develop and evaluate irrigation management systems and determine their influence on crop yield and quality, and water quality.
1b. Determine impacts of conservation management practices on crop yield, quality and climate resiliency, greenhouse gas emissions, and air and water quality.
2. Develop and expand robust datasets focused on water use efficiency, air and water quality, greenhouse gas emissions, and other sustainable cropping system metrics in humid subtropical environments.
2a. Contribute to long-term water quality assessments of cotton- and rice-based cropping systems.
2b. Integrate greenhouse gas emission, yield metrics, and phenotypic architecture datasets to improve models, scaling factors, and tools for current and future climate scenarios.
3. Develop and deploy agronomically sound irrigation and drainage management tools, practices, and technologies that improve water resource management and return on investment in a changing climate.
3a. Devise techniques and/or tools to identify, inventory, and create conservation milestones for agricultural water resource management in the Lower Mississippi River Basin (LMRB).
3b. Evaluate the utility of multiple strategies for managed aquifer recharge in the Lower Mississippi River Basin (LMRB).
Approach
To optimize the management of irrigated cropping systems in the Lower Mississippi River Basin, research must aim to sustain or improve agricultural production and natural resources through optimized management practices that sustain yield and grain quality while reducing inputs and environmental risks. Research will focus on field-scale to farm-scale quantification of water quantity, water quality, and greenhouse gas emissions in response to crop management. Comparisons of production practices in rice-based and cotton-based systems include irrigation automation, nutrient management, crop establishment, tillage, cover crops, and residue management will be investigated. Improved understanding of aquifer decline and solutions to arrest decline through watershed planning that focuses on return on investment and managed recharge will be studied. Data collected on the impact of these practices will be curated into robust datasets that will be used to devise tools and technologies and improve existing models. This research is expected to augment the existing body of knowledge of agricultural water resources, inform resource managers and provide farm managers with new tools, practices and technologies that will reduce groundwater use and produce a profitable crop.
Progress Report
Progress was made in improving management practices for irrigated cropping systems in humid subtropical environment. In rice, research in furrow irrigated rice both with and without cover crops, different genotypes and fertilizer inputs continued and comparing irrigation delivery methods began. Irrigation automation research sites were newly established. A manuscript on improving cascade irrigated rice was published and field research in this research area will continue at the field-scale to determine best practices and the associated field variability. An ARS researcher at Jonesboro, Arkansas, made an invited presentation on cascade irrigated rice in the water challenged region of coastal Texas, while another will present at the Florida rice field day. ARS researcher presented at the USA Rice/Ducks Unlimited Regional Conservation Partnership Summit. Continued analysis of water use and yield metrics occurred at the study sites. ARS researchers attended and presented at the Arkansas Water Summit, a consortium of researchers working in water resources.
The unit continues to work toward the development and expansion of robust data sets that focus on water management, greenhouse gas emissions, and other sustainability metrics. Progress on edge of field and in-stream water quality data continue. A manuscript on the utility of filter strips and cover crops using edge of field data was presented at a specialty conference on soil erosion and the manuscript was submitted to the special issue of the conference. An ARS researcher met with the national NRCS water quantity and water quality team to discuss challenges and successes from edge of field monitoring sites. One of the CEAP watersheds was shifted from the Lower St. Francis watershed to the Cache Critical Groundwater Area due to a lack of interest on the part of the new producer at the original study site. Testing of automated static flux chambers continued. Trend analysis of high night time temperature and the impact on rice production is nearly complete. Field-integrated measurements of greenhouse gas emissions and chamber based measurement both continue. Two nitrous oxide sensors were deployed in furrow irrigated rice fields. Static vented chamber measurements were also made in the same field to allow for a comparison. Older eddy covariance data were curated and manuscripts from this effort are being worked on. An effort toward updating EC sensors was made this fiscal year. Recognition of the an ARS researcher expertise in the area of sustainability continues through significant invitations to present on their research topics and contribute to colloquium report on methane. These invitations include but are not limited to the American Academy of Microbiology-American Chemical Society, International Rice Research Institute: Reducing Methane Emissions from Rice: from mechanistic understanding to scalable crop management options -REMET Rice, Food and Agriculture Organization of the United Nations Asia and Pacific Region.
Research on this objective has progressed this year. Continued expansion of our efforts to identify on farm reservoirs has expanded to include Synthetic Aperture Radar data that is publicly available. The original analysis of using GIS tools on LiDAR data has required further refinement. New LiDAR imagery is expected for much of the region of interest in the coming year, which will further our capacity to identify land levelling changes on the landscape. Progress on the Managed Aquifer Recharge project has also progressed. This was the second year of moving water from the reservoir into the infiltration galleries during the non-growing season. Water quality samples were collected regularly from the site. Unfortunately, the water level in the monitoring wells has not yet been impacted by the MAR activity to date.
The unit’s research in water resources management has earned two ARS researchers two major awards, including: 2023 Rice Researcher of the Year at the 26th Annual National Conservation Systems Cotton and Rice Conference and the 2023 Precision Agriculture Researcher of the Year at the 26th Annual National Conservation Systems Cotton and Rice Conference. In addition, an ARS researcher was invited to serve on the executive committee of the Rice Technical Working Group.
Accomplishments
1. Shifting rice cultivation from continuously flooded to AWD irrigation did not affect grain yield and reduced seasonal CH4 emissions by 66%. Flooded rice cultivation accounts for 7-11% of total anthropogenic CH4 and N2O emissions. Better understanding of gas flux dynamics and estimates of emissions based on field measurements are needed to develop effective mitigation options for rice. A 5-year field study on commercial farm was conducted to assess the influence of rice rotation and intermittent irrigation (Alternate wetting & Drying: AWD) on CH4 and N2O emissions and grain yield. Closed vented chamber technique was used to measure fluxes of CH4 and N2O. Findings by ARS researchers in Jonesboro, Arkansas, show a 66% reduction of CH4 emissions and minimal N2O emissions without significant crop yield penalty when fields were shifted from flooded to AWD practice. The study also showed apparent seasonal variation in CH4 emissions caused by weather and irrigation within the same commercial farm. Results from this study can be used by researchers, extension workers, and farmers in predicting accurate estimates of GHG emission factor and improves GHG model validation.
2. Early cascade rice irrigation shutoff conserves water. Improving rice irrigation in the Mid-South will impact the status of the declining Mississippi River Valley Alluvial Aquifer. Cascade flooding of rice is the traditional method of irrigation used on approximately half of the rice grown in the Mid-South. ARS researchers in Joneboro, Arkansas, discovered that early cascade irrigation shutoff (ECIS) is a method that promises to reduce irrigation use by an average of 16% relative to cascade flooding. Using simple sensors to indicate when irrigation water has reached an optimal level, farmers may use the technology to automatically shutoff irrigation. Improving management to water management in cascade rice production has the potential to conserve water resources in the Mid-South.
3. Groundwater sustainability could be improved through managed aquifer recharge. Groundwater overdraft from the Mississippi River Valley alluvial aquifer has resulted in several cones of depression in eastern Arkansas, largely due to groundwater use for irrigation. A study was undertaken by ARS researchers in Jonesboro, Arkansas, to investigate whether infiltration basins could be used to enhance local groundwater recharge. Results showed that the removal of surface soil, higher in clay content, provided a quicker pathway for surface water to infiltrate the unsaturated zone. This subsurface zone of unsaturated sand above the water table, which has expanded due to declining groundwater levels, provided a natural filter as well as a potential underground storage area. These findings support infiltration basins as a method to increase aquifer recharge within northeast Arkansas, which could be one way to promote groundwater sustainability within a primarily agricultural area dependent on reliable irrigation.
Review Publications
Reba, M.L., Wright, R. 2023. Tailwater recovery. SERA-IEG 17 Bulletin. Available: https://sera17.wordpress.ncsu.edu/tailwater-recovery/.
Welikhe, P., Williams, M.R., King, K.W., Bos, J.H., Akland, M., Baffaut, C., Beck, G., Bierer, A.M., Bosch, D.D., Brooks, E., Buda, A.R., Cavigelli, M.A., Faulkner, J., Feyereisen, G.W., Fortuna, A., Gamble, J.D., Hanrahan, B.R., Hussain, M., Kovar, J.L., Lee, B., Leytem, A.B., Liebig, M.A., Line, D., Macrae, M., Moorman, T.B., Moriasi, D.N., Mumbi, R., Nelson, N., Ortega-Pieck, A., Osmond, D., Penn, C.J., Pisani, O., Reba, M.L., Smith, D.R., Unrine, J., Webb, P., White, K.E., Wilson, H., Witthaus, L.M. 2023. Uncertainty in phosphorus fluxes and budgets across the U.S. long-term agroecosystem research network. Journal of Environmental Quality. 52(4):837-885. https://doi.org/10.1002/jeq2.20485.
Dale, D., Liang, L., Zhong, L., Reba, M.L., Runkle, B. 2023. Deep learning solutions for very high resolution mapping of contour levee rice production systems. Computers and Electronics in Agriculture. 211. Article 107954. https://doi.org/10.1016/j.compag.2023.107954.
Leslie, D.L., Reba, M.L., Czarnecki, J.B. 2022. Managed aquifer recharge using a borrow pit in connection with the Mississippi River Valley alluvial aquifer in northeastern Arkansas. Journal of Soil and Water Conservation. 78(1):44-57. https://doi.org/10.2489/jswc.2023.00021.
Massey, J., Smith, M., Jardim, T., Avila, L., Hashem, A., Reba, M.L. 2022. Early cascade rice irrigation shutoff (ECIS) conserves water: implications for cascade flood automation. Irrigation Science. 41:355-364. https://doi.org/10.1007/s00271-022-00821-y.
Bueno, M.V., Roel, A.R., Faria, L.C., Massey, J., Parfitt, J.M. 2022. Land-forming for irrigation (LFI) on a lowland soil protects rice yields while improving irrigation distribution uniformity. Precision Agriculture. 24:310-325. https://doi.org/10.1007/s11119-022-09946-8.
Karki, S., Adviento-Borbe, A.A., Runkle, B., Moreno-Garcia, B., Anders, M., Reba, M.L. 2023. Multiyear methane and nitrous oxide emissions in different irrigation management under long-term continuous rice rotation in Arkansas. Journal of Environmental Quality. 52(3):558-572. Available: https://doi.org/10.1002/jeq2.20444.
