No. 5 Article 5/April 28, 2006

Liquid Carriers for Herbicides After Corn Emergence

Each year at about this time, a few questions arise about applying post-emergence corn herbicides in a liquid nitrogen solution carrier in hopes of saving a trip across the field. The most common carrier people ask about is 28% UAN solution. While applying high rates of UAN by itself can cause corn injury, adding a postemergence herbicide can greatly increase corn injury. Most postemergence corn herbicide labels restrict application with UAN as a carrier, but many allow a lower rate (usually 1 to 4 quarts per acre) of UAN to be added as a spray additive to enhance control of particular weed species, most commonly velvetleaf. It is most advisable to not apply postemergence corn herbicides in a liquid fertilizer carrier, as severe corn injury can occur.--Aaron Hager

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