Harvest Management Effects on Dry Matter Yield, Forage Quality, and Economic Return of Four Cool-Season Grasses

Abstract

Perennial cool-season grasses are widely grown in Pennsylvania and the northeast USA for forage. Harvest management practices that maximize annual economic return of these grasses have not been adequately identified. The objectives of this research were to determine tbe effect of harvest number on dry matter (DM) yield, forage quality, and economic return of orchardgrass (Dactylis glomerata L.), reed canarygrass (Phalaris arundinacea L), smooth bromegrass (Bromus inermis Leyss.), and timothy (Phleum pratense L.). Established stands of these grasses on a Murrill silt loam (fine-loamy, mixed, mesic Typic Hapludult) were harvested at intervals of 70, 45, and 35 d (two, three, or four harvests per year, respectively) during four consecutive years. In all years and for all grass species, forage quality (crude protein [CP] and digestible dry matter [DDM]) was greatest when the forage was harvested at a 35-d interval. However, in years when rainfall was below normal, the 35-d harvest interval resulted in the lowest DM yields. There was no difference in net economic return for any species when rainfall was below normal. In years when rainfall was at or above normal, the 35 and 45-d harvest interval produced greater net economic return than the 70-d interval for all grasses except timothy, which did not differ in economic return among harvest schedules. The highest quality forage and greatest net economic return were obtained in years with normal or greater rainfall when orchardgrass, reed canarygrass, and smooth bromegrass were harvested at intervals of 35 to 45 d. Harvest intervals for the same species in dry years and timothy in either dry or wet years should be based on the nutrient needs of the consuming animal. Forage for high producing animals (e.g., lactating dairy cows), which require relatively high forage digestibility to achieve adequate intake levels, must be harvested more frequently (35 to 45 d) than forage for animals with lower intake requirements (e.g., nonlactating cows).