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 Evaluation of AMS replacement products in glyphosate solutions
Excerpted from K-State Agronomy e-Updates
Number 17
January 26,2006
Ammonium sulfate (AMS) is commonly added to glyphosate solutions before application in order to condition hard water and increase absorption by the target weeds. In its dry form, AMS words well and is relatively inexpensive, but it can be bulky to handle. AMS is added at the rate of 17 pounds per 100 gallons of solution. Liquid AMS products are also available and the equivalent use rate is 5 gallons liquid AMS per 100 gallons of solution. Dry and liquid AMS have performed equally well.
In recent years, many AMS replacement products have entered the market. The main selling point of these products is they have lower use rates than liquid AMS and are easier to handle than dry AMS. At K-State, we have compared the performance of AMS to several of these AMS replacement products, using their recommended rates, with glyphosate.
In these tests, AMS dramatically improved weed control with glyphosate compared to glyphosate alone. Of the AMS replacement products, only those that actually contained AMS and were applied at Comparable rates provided similar control to AMS. None of the commercially available low-rate AMS replacement products worked as well as AMS. In fact, weed control from glyphosate with the low-rate AMS replacement products (recommended at rates of 1 to 2 quarts per 100 gallons of spray solution) was often no better than weed control with glyphosate alone.
--Dallas Peterson, Weed management specialist, Kansas State University |
