The Effect of Herbicide on the Re-Establishment of Native Grasses in the Blackland Prairie

Abstract

ABSTRACT: The Blackland Prairie of east-central Texas, the southernmost tip of the once vast North American Tallgrass Prairie, now covers only 1% of its original 6.8 million hectares. Thus, there is considerable interest in restoration and re-establishment of this endangered ecosystem. In a randomized complete block field experiment conducted near San Marcos, Texas, we tested the effectiveness of the post-emergent herbicide imazapic on weed control, establishment, and growth of four C4 warm-season grasses native to the Blackland Prairie (Andropogon gerardii, Sorghastrum nutans, Schizachyrium scoparium, and Bouteloua curtipendula). Treatment with three different levels of imazapic (0.07, 0.092, and 0.138 kg ai/ha) all significantly increased seedling density of native grasses, and low-to-medium levels of imazapic increased seedling shoot growth and flowering relative to water controls. End-of-season aboveground biomass of native grasses also increased with imazapic treatment while that of broadleaf species...