Japanese Brome Response to Atrazine in Combination With Nitrogen Fertilizer in the Mixed Prairie

Abstract

Atrazine was used to control Japanese brome in conjunction with nitrogen fertilization to determine if herbage production could be increased more than by fertilization alone. Atrazine treatments included a single application, application in alternate years, and application for two or three consecutive years. Atrazine did not significantly increase production more than fertilizer alone and caused some decreases in western wheatgrass production at low rates of N in one year at one location. Unless atrazine was applied in two or more years, Japanese brome was a prevalent the second growing season after application as where it had never been controlled. Application of atrazine in consecutive years increased shortgrass production at one location.