Volume 2, Issue 4 (April 2005)
A Novel Water Conditioning Adjuvant for Use with Formulated and Nonformulated Glyphosate
Glyphosate is a weak acid, sold as the isopropylamine, ammonium, potassium, or trimethylsulfonium salt. A water conditioning adjuvant such as diammonium sulfate is commonly recommended for glyphosate application in hard water. This is especially necessary for applications to velvetleaf, which has calcium-rich leaves. There is an application preference to handle liquids rather than solids. Our goal was to identify a liquid water conditioning adjuvant with high specific activity, which is cost effective, as well as efficacious across herbicides and weed species. The specific objective of the research was to evaluate the performance characteristics of NT3 as a water conditioning adjuvant for various glyphosate formulations on several weed species. Studies were conducted in the greenhouse with supplemental lighting. Ammonium sulfate was a more effective water conditioning adjuvant than ammonium nitrate, ammonium hydroxide, or sulfuric acid for use with glyphosate on velvetleaf. The novel water conditioning adjuvant, NT, at 1 % was as effective as or more effective than ammonium sulfate at 2 % with glyphosate across various glyphosate salts and formulations and across the weed species, velvetleaf, giant foxtail, and common lambsquarters. Furthermore, it provided limited rainfastness. NT is a liquid, it has a higher specific activity than ammonium sulfate, and it is efficacious across weed species.