Effects of CO2, N2, Air, and Nitrogen Salts on Spray Solution pH
Water samples from eight locations, ranging in pH from 7.1 to 8.5, were tested to determine the effect of carbon dioxide (CO2) pressurization on pH. After pressurization with CO2the pH of the water decreased 1.8 to 4.1 pH units. An increase of 0.4 to 1.2 pH units occurred after the CO2pressurized water exited a spray nozzle. The use of N2or air as a pressurizing gas had very little effect on pH. The addition of diammonium phosphate, urea-ammonium nitrate (UAN)3, or ammonium sulfate had only minor effects on water pH. The addition of monoammonium phosphate reduced water pH to 4.6 to 5.5. The physical/chemical properties and activity of a herbicide may be altered with the change in spray solution pH by using CO2to pressurize the spray solution.