Oral Presentation Society for Freshwater Science 2026 Annual Meeting

Nitrous oxide production and emissions in tailwater recovery systems in Eastern Arkansas over a year (2025). (135761)

Nellie I Little 1 , Shannon L Speir 1 , Auldyn L Faulk 1 , Frank E Johnson II 2 , Mike B Daniels 3
  1. Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, Arkansas, United States of America
  2. U.S. Department of Agriculture, Agriculutral Research Serivce , Oxford, Mississippi, United States of America
  3. Department of Crop, Soil, and Environmental Sciences, Cooperative Extension Service, University of Arkansas Division of Agriculture, Little Rock, Arkansas, United States of America

Eastern Arkansas is dominated by row-crop production; however, local aquifer declines have resulted in the implementation of on-farm water management systems to support continued irrigation needs. As such, many farms in Eastern Arkansas have introduced tailwater recovery systems (TWRS) that collect runoff from adjacent fields, storing it in ditches and reservoirs for recirculation and reuse. While downstream water quality benefits have been well documented, we lack understanding of the potential role of TWRS in releasing greenhouse gases, like nitrous oxide (N2O), due to the accumulation of nutrients in runoff from cropland. Here, we sampled three Arkansas Discovery Farm sites with TWRS’s in Eastern Arkansas, collecting samples to determine the production (e.g., dissolved gas samples) and surface emissions (e.g., via floating chambers) from TWRS. Preliminary results indicate that higher water column nitrate concentrations drive higher N2O emissions from TWRS’s. Surprisingly, peaks of N2O emissions were observed in the winter, which did not align with the growing season when fertilizer application typically occurs. Overall, results suggest that TWRS predominately act as a net source of N2O to the atmosphere. While TWRS provides benefits to water quality and water conservation, our results highlight a need to adapt TWRS to mitigate their production and emissions of N2O hopefully leading to more resilient farms under a changing climate.