Roundup PowerMAX as Influenced by Water Quality and Ammonium Sulfate

Water is the main carrier used in most spray applications to deliver herbicides to the soil or target weeds. The quality of water plays an important role in the success or failure of herbicide treatments, especially weak acid herbicides, such as gylphosate. Defining the role of water quality on glyphosate efficacy is important because of its increased use over the past 15 years. In an effort to understand the effects of water quality and water conditioning agents on glyphosate efficacy, five field trials were established near Lubbock, TX in the spring and summer of 2012. Test plants included wheat, Palmer amaranth, Russian-thistle, and kochia. The experiments were randomized complete block designs with four replications. Main plots included the application of six water sources mixed with glyphosate at two different rates while subplots included the presence or absence of ammonium sulfate.