Nitrogen volatilization from Arizona irrigation waters

A laboratory study was initiated to investigate the effects of temperature (25, 30, 35, and 40 °C) and water quality on the loss of fertilizer nitrogen (N) through volatilization out of irrigation waters collected from 10 different Arizona sources. A 300‐mL volume of each water source was placed in 450‐mL beakers open to the atmosphere in a constant‐temperature water bath with 10 mg of analytical‐grade ammonium sulfate [(NH4)2SO4] dissolved into each sample. Small aliquots were drawn at specific time intervals over a 24‐h period and then analyzed for ammonium (NH4 +)‐N and nitrate (NO3 −)‐N concentrations. Results showed potential losses from volatilization to be highly temperature dependent. Total losses (after 24 h) ranged from 30–48% at 25 °C to more than 90% at 40 °C. Volatilization loss of fertilizer N from irrigation waters was found to be significant and should be considered when making decisions regarding fertilizer N applications for crop production in Arizona particularly when using ammonia‐base...