Mapping the nutrient variability of Kansas grasslands in the Conservation Reserve Program
A new Applied Animal Science field study is shedding light on how the nutrient composition of CRP lands in Kansas differs across locations and time of year
Champaign, IL, February 9, 2026—For livestock producers facing forage shortages during drought and other environmental disruptions, land enrolled in the US Department of Agriculture’s Conservation Reserve Program (CRP) can become an important supplemental feed resource. A new field case study published in Applied Animal Science provides detailed data on the nutrient composition of standing CRP forages across Kansas, helping to provide actionable information for producers, extension professionals, and policymakers. “Under certain situations, usually when forage is in very short supply because of environmental conditions such as drought, CRP land can be used for hay production. Using this resource effectively is critical,” said Bill Weiss, PhD, PAS, Dipl. ACAS, editor in chief of Applied Animal Science. “This article provides valuable data on the nutrient composition of hay produced from CRP land and how the composition differs over geographic locations and months.”
The study’s lead author, Jason Warner, PhD, PAS, of the Kansas State University Department of Animal Sciences and Industry, Manhattan, KS, USA, explained, “Despite the importance of CRP lands, relatively little peer-reviewed data exist on the nutritional characteristics of CRP forages, particularly across seasons.”
To fill this knowledge gap, the study evaluated 294 forage samples collected monthly over a two-year period from 25 CRP tracts across 16 Kansas counties. Samples were represented from both eastern and northwestern regions of the state.
“Our objective,” said Warner, “was to document what the nutrient profile of standing CRP forage actually looks like across the year and across regions, and how much variability producers and nutritionists should expect to see.”
Results showed that nutrient composition followed expected seasonal patterns for native warm-season grasslands. Crude protein and energy values generally increased during the growing season and decreased during dormancy, and fiber concentrations were greatest in winter months. Eastern Kansas samples tended to reach peak energy concentrations earlier in the season than those from northwestern Kansas, reflecting differences in precipitation, species composition, and growing conditions.
Macromineral concentrations also varied throughout the year. Calcium and potassium showed wider ranges and greater variability than phosphorus and magnesium, with potassium concentrations increasing markedly during active growth. Phosphorus levels, while seasonally responsive, were generally low across regions, consistent with previous reports for native grass forages.
“One of the key takeaways is the amount of variation we observed within the same month,” Warner said. “Even when overall trends were clear, individual samples could differ substantially depending on species mix, prior management, and local conditions. That reinforces the value of forage testing when CRP forage is being considered for grazing or haying.”
Caption: New research in Applied Animal Science provides important nutrient composition insights for standing Conservation Reserve Program forages across Kansas throughout the year in relation to various environmental and management factors (Credit: Jason Warner).
Importantly, the authors emphasize that the study was not designed to make prescriptive feeding recommendations. Instead, it provides a foundation of reference data that can support more informed decision-making for producers, extension professionals, and nutritionists when CRP forage is used under limited scenarios. The information can also aid USDA Farm Service Agency staff as they make disaster-declaration or forage-accessibility decisions.
“These data are useful for producers, extension personnel, and regulators who need realistic expectations of forage quality under CRP release conditions,” Warner said. “They also highlight the inherent variability of nutrient data, and the importance of analysis specific to each producer’s unique scenario.”
By documenting seasonal and regional variability across a large number of sites, the study contributes to improved feed composition databases and underscores the need for operation-specific forage analysis. The authors note that similar assessments in other CRP-heavy states could further strengthen the evidence base supporting both livestock nutrition and conservation policy decisions.
The article appears in the February issue of Applied Animal Science.
Notes for editors
“Case Study: Assessment of nutrient content of Kansas grasslands enrolled in the Conservation Reserve Program,” by J. M. Warner, A. G. Schwartz, B. J. Fraser, J. W. L. Banks, J. K. Farney, J. W. Waggoner, and S. K. Johnson (https://doi.org/10.15232/aas.2025-02730), Applied Animal Science, volume 42, issue 1 (February 2026), published by FASS and Elsevier.
This article is openly available at https://doi.org/10.15232/aas.2025-02730.
To schedule an interview with the author(s), please contact Jason Warner, PhD, PAS, at jasonwarner@ksu.edu.
About Applied Animal Science
Applied Animal Science (AAS) is a gold open access, peer-reviewed scientific journal and the official publication of the American Registry of Professional Animal Scientists (ARPAS). In continuous publication since 1985, AAS is a leading outlet for animal science research and is indexed by Scopus and ESCI (Clarivate’s Emerging Sources Citation Index). The journal welcomes novel manuscripts on applied technology, reviews on the use or application of research-based information on animal agriculture, commentaries on contemporary issues, short communications, and technical notes. Topics that will be considered for publication include (but are not limited to) feed science, farm animal management and production, dairy science, meat science, animal nutrition, reproduction, animal physiology and behavior, disease control and prevention, microbiology, agricultural economics, and environmental issues related to agriculture. Themed special issues also will be considered for publication. www.appliedanimalscience.org
About the American Registry of Professional Animal Scientists (ARPAS)
The American Registry of Professional Animal Scientists (ARPAS) is the organization that provides certification of animal scientists through examination, continuing education, and commitment to a code of ethics. Continual improvement of individual members is catalyzed through publications (including the AAS journal) and by providing information on educational opportunities. ARPAS is affiliated with five professional societies: American Dairy Science Association, American Meat Science Association, American Society of Animal Science, Equine Science Society, and Poultry Science Association. www.arpas.org
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