Species Susceptibility to Atrazine Herbicide on Shortgrass Range

Abstract

Atrazine was applied at 2 kg/ha for three consecutive years on shortgrass range in northeastern Colorado. The atrazine controlled all annual plant species, greatly reduced frequency of occurrence of cool-season perennial grasses, and increased drought survival of warm-season perennial grasses and two warm-season perennial forbs. Other species varied in their susceptibility to atrazine. The species frequency method of vegetation sampling used in this study provided reliable data for 27 of the approximately 100 species encountered on this range.