Case Study: Assessment of nutrient content of Kansas grasslands enrolled in the Conservation Reserve Program

The objective was to assess nutrient compo-sition of standing Conservation Reserve Program (CRP) forages across Kansas throughout the year in relation to various environmental and management factors affecting forage quality. Forage samples (n = 294) from a total of 25 different sites across 16 counties through-out Kansas were collected over 2 yr. Samples were collected monthly and analyzed in a single commercial laboratory for CP, ADF, NDF, calculated energy, and macromineral concentrations to determine nutrient composition changes throughout the year. Whereas nutrient compo-sition varied considerably by month, CP, fiber, and sub-sequent energy measurements generally followed typical seasonal patterns for warm-season forages. In May, for-age samples collected from eastern Kansas were greater in TDN and NEg and tended to have increased NEm com-pared with northwestern Kansas samples. Concentrations of most macrominerals appeared to change in response to the growing season, with Ca and K having increased ranges and variation within months compared with P and Mg. Calcium concentrations appeared increased relative to P, and K concentrations increased during the growing season. The objective of this case study was to largely report nutrient data and associ-ated variability in such data that exist. Knowledge of nu-trient composition of CRP forages is critical for informed livestock management and policy decision-making, and these data will greatly contribute to helping fill an existing gap in the literature.