Yield of switchgrass ( Panicum virgatum L.) as influenced by cutting management

Abstract

Switchgrass ( Panicum virgatum L.) biomass, which is of a good quality in the middle of summer, when cool-season grasses are unproductive, is a very important source of forage. This study measured the influence of the date of first harvest and cutting height on the first and regrowth yields of switchgrass cultivars Blackwell and Cave in Rock. The experiment was conducted in Blacksburg, VA, USA on a Groseclose-Poplimento soil to determine the influence of four dates of harvest and two cutting heights on the yield of switchgrass in 1990, and the influence of the treatments in previous years on the yields in 1991 and 1992. The first yield of both cultivars increased as the date of first harvest was delayed and the cutting height reduced. The regrowth yield of both cultivars declined as the date of first harvest was delayed. A shorter cutting height caused reductions in vigour and yield potential in the second year, whilst in the third year the harvested yield was only 40–50% of that obtained from previously unharvested stands.