PSI-8 Exploring the Relationship Between Soil Composition and Forage Characteristics in Cool Season Grass/Legume Pastures

Abstract

Abstract The objective was to evaluate the relationship between soil nutrient composition and forage characteristics in cool-season grass/legume pastures in June. Forage and soil samples were collected from a total of 15 distinct locations with varying topography and forage species. Forage samples (0.25 m2) were clipped at the crown and weighed to determine total biomass production. Forage samples were sorted by species. Soil samples were collected utilizing either a manual probe or drill auger (Oakfield Apparatus, Oakfield, WI) depending on soil compaction. Forage and soil samples were analyzed for chemical composition at a commercial laboratory. Percent legume was positively correlated (r ≥ 0.51; P ≤ 0.05) with forage crude protein (CP), total digestible nutrients, Mg, Cu and B and negatively correlated (r ≤ -0.81; P < 0.01) with total forage biomass, neutral detergent fiber and acid detergent fiber. Soil organic matter and N release both had positive, strong correlations (r ≥ 0.53, P ≤ 0.04) with soil S, B, Fe, Cu and NO3-N. Soil pH was negatively correlated (r = -0.63; P ≤ 0.01) with soil H, but positively correlated (r ≥ 0.60, P ≤ 0.02) with forage Al and Fe. Soil P was not only positively correlated (r ≥ 0.73, P ≤ 0.01) with soil S, B and Zn but also positively correlated (r ≥ 0.73, P ≤ 0.01) with forage CP, P, and K. Soil K base saturation percent was positively correlated (r ≥ 0.55, P ≤ 0.04) with forage CP, P, K, Fe, Zn, Al, and B. Additionally, forage Fe was positively correlated (r ≥ 0.56, P ≤ 0.03) with forage P, K, and Zn, as well as soil Zn, B, P, and S. In conclusion, percent legume in forage was related to several forage quality characteristics, and multiple relationships exist between and among forage and soil characteristics.