Pre-harvest glyphosate is applied to cereal grains to remove weeds. However, it has been claimed that oat compositions are affected by pre-harvest glyphosate. Research was conducted to evaluate differences in properties of β-glucan in the treated versus untreated oat groats. Two oat cultivars (Rockford and Souris) were grown at Minot and Prosper, North Dakota in 2015, and glyphosate was sprayed during the soft dough stage, physiological maturity stage, or not applied. β-Glucan viscosity was not significantly (p > 0:05) affected by treatment at soft dough or physiological maturity stages. Use of glyphosate at the soft dough stage significantly (p < 0:05) reduced the percentages of β-glucan content and solubility versus untreated samples. Treatment at soft dough and physiological maturity stages significantly (p < 0:05) increased β-glucan molecular weights compared to untreated controls. Therefore, glyphosate can be applied at the physiologically mature stage of grain development because β glucan properties from the groats were not negatively affected.

Pre-harvest glyphosate is often applied to cereal crops, such as oats, to insure uniform grain ripeness at harvest. However, some buyers have claimed that this practice negatively affects oat end product quality. Oat samples were grown in two different growing locations for each of two crop years, and glyphosate was applied at the soft dough, physiological maturity, or not applied. Groat quality and starch quality parameters were analyzed, and rolled oats were produced to analyze end product quality. Groat hardness, groat percentage, and percent plump groats were significantly (P<0.05) affected by glyphosate application at the soft dough stage. However, application of glyphosate at physiological maturity did not appear to detrimentally affect groat starch or end product quality. Therefore, pre-harvest glyphosate application isappropriate for oats providing it occurs after plants reach physiological maturity.