Effect of Harvest Processes on the Nutritive Value of Kentucky Bluegrass Residue from Seed Harvest

Abstract

Kentucky bluegrass (Poa pratensis L.) fields were historically burned following seed harvest to remove post-harvest residue and maintain stand productivity, but regulations were imposed on field burning. Reduced-burn or non-burn production systems remove residue in part by baling, and the baled residue is often utilized for forage. It was unknown if harvest processes (swathing, combining seed, and baling) and the time between combining and baling affected forage nutrient content. Experiments at two locations evaluated the effect of harvest method and timing on crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), lignin, and 48-h in vitro true digestible dry matter (IVTDDM). At the Potlatch, WA, experiment, CP decreased by 8 g/kg DM, IVTDDM decreased by 38 g/kg DM, NDF increased by 48 g/kg DM, ADF increased by 26 g/kg DM, and lignin did not change before and after swathing. Forage nutrient content did not change between before and after combining seed or baling. At the Pullman, WA, location, IVTDDM decreased by 1.8 g/kg/day DM, NDF increased by 2.8 g/kg/day DM, ADF increased by 1.4 g/kg/day DM, lignin increased by 0.2 g/kg/day DM, and CP was unchanged when baling was delayed 23 days after seed harvest. Baling Kentucky bluegrass residue soon after combining with as much leaf content as possible will result in the highest nutritive value.