Interseeding Warm-season Grasses Followed by High Intensity Grazing Enhances Pasture Productivity

Abstract

Pasture renovation by interseeding can be an efficient way to introduce native warm-season grasses into low-producing cool-season pastures, provided that the existing sod can be managed to favor establishment and stand persistence. The objectives were to test interseeding warm-season grasses into cool-season pasture using grazing or herbicide sod suppression treatments and the effects of prescribed grazing events on stand development. The grazing treatment was applied using sheep at a high stocking rate to achieve a residual grazing height of < 2.5 cm in autumn and in the spring prior to seedling emergence. The herbicide treatment was an application of glyphosate in early October. Native warm-season grasses were seeded in mid-March (2004 and 2005). Warm-season grass biomass harvested the year after establishment was greater (P < 0.01) for the herbicide sod suppression treatment (5700 kg/ha) than the grazing treatment (20 kg/ha). Three years of prescribed grazing significantly (P < 0.01) enhanced the warmseason grass composition from 56 to 70% and from 1 to 12% in the herbicide and grazed sod suppression plots, respectively. Herbicides are integral to successfully interseeding warm-season grasses into cool-season pastures. Shortduration, high-density grazing can be appropriately timed to increase the competitiveness of warm-season grasses and decrease the cool-season grasses of interseeded stands.