As I travel around the southeastern part of the province the crops are up and growing and I see sprayers in the field. I also see lots of spray, hoses and pumps sitting next to wetland areas. Does the quality of water that you use in your sprayer affect the level of weed control that you will get? Absolutely!
For Group 1 herbicides: levels of bicarbonates higher than 500 ppm can reduce the efficacy of these herbicides in controlling weeds.
For Group 2 herbicides: sulfonylurea herbicides have high levels of activity at low rates. However, SU herbicides should not be applied to soils with a pH of 7.9 or greater. Ally will break down quickly when mixed in a solution of pH less than 7.0.
For Group 4 herbicides: levels of bicarbonate 400 ppm or higher can reduce the efficacy of some of these herbicides in control- Water quality really does matterling weeds. A hardness of
600mg/L can almost totally deactivate this product.
For Group 6 herbicides: levels of bicarbonate 400ppm or higher can reduce the efficacy of some of these herbicides in controlling weeds.
For Group 9 herbicides: control will be reduced if foliage is heavily covered with dust. “Hard water” or water containing calcium, magnesium, or iron ions will reduce activity of glyphosate
proportional to the level of hardness. If water is extremely hard (greater than 700 ppm or 40 grains), another water source should be found. Dirty water or water with suspended soil or organic matter will reduce control.
For Group 10 herbicides: hard water cations react with glufosinate ammonium thereby reducing overall pesticide efficacy.
For Group 22 herbicides: herbicide effi cacy is greatly affected by suspended solids including soil particles and organic matter.
To prevent issues from occurring, you should have the water source that you are planning to use in your sprayer tested. For more information on Saskatchewan water quality and how it affects your herbicide spray program, refer to this factsheet: http://www.agriculture.gov.sk.ca/Default.aspx?DN=27120252-dc56-450b-8738-b9a6464aea25
