Impact of Harvest Management on Forage Production and Nutrient Removal by Smooth Bromegrass on a Vegetated Treatment Area

Abstract

Beef cattle ( Bos taurus L.) feedlots pose serious environmental challenges associated with nutrient runoff. Smooth bromegrass ( Bromus inermis Leyss.) is a perennial rhizomatous grass that is widely used for forage production in the USA and Canada. The objective of this research was to determine the best management system for producing forage from a vegetated treatment area (VTA) while maintaining the capacity of the VTA to remove nutrients from feedlot effluent. Four harvest management treatments (1-, 2-, and 3-harvest per year and an un-harvested control) were applied during spring 2005 and evaluated over a 5-yr period in a smooth brome sward on a VTA near Howard, SD. Mean annual total forage production during a 4-yr period ranged from 6.2 Mg·ha ^-1 to 9.5 Mg·ha ^-1 for 1- and 3-harvest systems, respectively. Nutrient removal by the bromegrass ranged from 148 kg·N·ha ^-1 and 15 kg·P·ha ^-1 for the 1-harvest treatment to 244 kg·ha ^-1 N and 24 kg·ha ^-1 P for the 3-harvest treatment. Results indicated that high amounts of smooth bromegrass forage could be produced and soil nutrients removed from 2- and 3-harvest systems without compro-mising stand vigor and persistence on a VTA in eastern South Dakota.