Can adoption of intensified forage systems reduce water, soil and nutrient loss associated with variable precipitation cycles in the Southern Plains?

Authors: KIKOYO, DUNCAN - Texas A&M University; Fortuna, Ann-Marie; SMITH, PATRICIA - Texas A&M University; Hunt, Sherry; Zhang, Xunchang; Flanagan, Paul; Busteed, Phillip; JEONG, JAEHAK - Texas A&M University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2025
Publication Date: 7/14/2025
Citation: Kikoyo, D., Fortuna, A., Smith, P., Hunt, S., Zhang, X.J., Flanagan, P.X., Busteed, P.R., Jeong, J. 2025. Can adoption of intensified forage systems reduce water, soil and nutrient loss associated with variable precipitation cycles in the Southern Plains?. Meeting Abstract. American Society of Agricultural and Biological Engineers, Toronto, Canada, July 13-16, 2026.

Interpretive Summary:

Technical Abstract: Current, sustainable agricultural intensification (SAI) studies have focused primarily on assessing the impacts of individual practices, such as reduced tillage, on soil and nutrient loss from farmland, but research on integrated systems is limited. If not properly managed, some of these suggested SAI practices could lead to increased environmental degradation, potentially offsetting the productivity benefits. Integrated crop and pasture-based livestock systems can benefit from alternative management practices that address nutritional needs of livestock, adapt to variable weather, and minimize environmental degradation. This study assessed the impacts of cool- and warm-season mixed forage intensification systems on water, soil, and nutrient retention in the variable weather patterns of Southern Great Plains agroecosystems. Using the Agricultural Policy/Environmental eXtender (APEX) model, summer and winter forage crop rotation systems in grazed and hayed watersheds were simulated and compared to single-crop tilled systems on 1.6 ha watersheds in El Reno, OK. We represented the mixed forage cover crops in APEX using the dominant crop in the forage mixture measured for six consecutive years. Results demonstrated that intensified alternative warm- and cool-season forage systems, either grazed or hayed, can enhance water, soil, and nutrient retention relative to prevailing conventionally tilled winter wheat. Over a 30-year simulation period (1977-2006), no-till winter wheat-sorghum rotations that incorporated multiple harvests increased retention of water by 16.4%, soil by 10.8%, nitrogen by 11.4%, and phosphorus by 9.6%, compared to conventionally tilled winter wheat. Conversely, multiple grazing operations improved water retention (by 15.9%) but resulted in increased soil and phosphorous losses (by 5.9% and 14.9% respectively) whereas changes in nitrogen losses were marginal. The benefits of intensified systems were more pronounced in dryer years (those with annual rainfall totals below the 25th annual precipitation percentile during the simulated period) compared to wet years (above 75th percentile), emphasizing their potential for improving drought resilience and environmental stewardship. These findings offer valuable insights for policymakers, farmers, and stakeholders to promote sustainable agricultural practices, enhance productivity, and mitigate soil and nutrient-related environmental impacts in the Great Plains.