Assessing CRP forage quality
Does nutrient content vary throughout the year?
By Jason M. Warner
Understanding seasonal changes in forage quality is necessary for development of sound management programs for grazing beef cattle. While pastures of either native or introduced forages represent the resource base most often considered, Conservation Reserve Program (CRP) lands are found throughout the United States and represent a significant source of forage for producers in some regions. The CRP program was established in the 1985 Farm Bill through the Farm Service Agency (FSA) that places environmentally sensitive land out of agricultural production and into conservation which can be released for grazing or haying depending on specific local conditions each year.
There are limited data on quality of CRP forages harvested for hay and even less information on nutrient content levels regarding standing CRP forages for grazing beef cattle is available. Information on standing forage quality is necessary for accurate supplementation and feeding recommendations for producers, thereby allowing for more efficient and economical use of resources. Soil type, years of enrollment in CRP, average annual precipitation, and management history all impact forage quality.
To better understand seasonal nutrient content changes of such forages across Kansas, a field study was recently conducted by researchers at Kansas State University (Schwartz et al., 2025; [1].
For this project, forage samples were collected monthly beginning in winter 2023 in conjunction with cooperating producers actively managing CRP tracts. A prearranged set of dates was determined to limit the variation of times that samples were collected within months. Samples were taken at cooperating producer locations in 19 counties across the state, and locations were classified as either western or eastern Kansas.
Random locations within the specific tracts were selected and samples were collected by hand clipping forage to a height of approximately 1 inch above the ground in 1 m2 quadrats. Samples were dried, ground and sent to a single laboratory for analysis (SDK Laboratories, Hutchinson, Kansas). Data from a total of 206 forage samples ranging from February 2023 to July 2024 were analyzed with similar proportions of samples between east (n = 102) and west (n = 104) regions.
Crude protein did not differ between regions within a sampling month, although tendencies were observed for May and November. In general, protein increased during the growing season and decreased during fall and winter. While acid detergent fiber was significantly different during July and December between the two regions, neutral detergent fiber did not differ between months or regions. In alignment with protein content changes, fiber levels for both measurements decreased during the growing season and increased as dormancy approached.
Total digestible nutrients was significantly different for February, March and July for the two regions with the highest levels observed from May through July. Calcium was significantly different only during December with phosphorus only different for May. Potassium was significantly different for the months of May and October while differences were observed for magnesium for samples collected in February, August, September, October and December.
Understanding the nutrient quality of CRP lands that are released for haying or grazing is critical for making informed supplementation and feeding decisions with producers. Numerous factors including precipitation, soil type, forage species composition and site management all impact forage quality. These data are important for producers, researchers and allied industry in making informed management decisions for beef cattle grazing CRP lands as well as conservation land managers.
References:[1] Schwartz, A. G., B. J. Fraser, J. W. L. Banks, S. K. Johnson, and J. M. Warner. 2025. Assessment of Nutrient Content of Kansas Grasslands Enrolled in the Conservation Reserve Program. Kansas Agricultural Experiment Station Research Reports: Vol. 11; Iss. 1.
Warner is an Extension cow-calf specialist in the Department of Animal Sciences and Industry at Kansas State University.
