Guodong Liu, Univ of Florida/TREC, 18905 SW 280th St, Homestead, FL 33031, Yuncong Li, University of Florida, University of Florida, 18905 SW 280th St., Homestead, FL 33031, and Ashok Alva, USDA-ARS, Vegetable and Forage Cro, 24106 N Bunn Road, Prosser, WA 99350-9687.
Temperature is an important factor influencing ammonia (NH3) emission from nitrogen (N) sources containing ammonium (NH4+) or other N sources transformed into NH4+ form applied to soils. This research was conducted using Biscayne Marl Soil (BMS), Krome Gravelly Loam (KGL) soils from Florida, Quincy Fine Sand (QFS), and Warden Silt Loam (WSL) soils from Washington. Each of the soils was amended with either potassium nitrate, ammonium nitrate (AN), ammonium sulfate (AS) or urea incubated at 11, 20 or 29 oC under 20% and 80% field water capacity (FC). A change in the rate of NH3 emission corresponding to 9 oC changes in temperature is expressed as the temperature quotient (Q9). The results showed that the maximum-cumulative NH3 emission (CAE) was 19.3 kg N ha-1 from the KGL soil. The CAE from the Florida soils was up to 20 fold greater than that of the Washington soils. The Q9 values from the WSL soil was up to 10 fold greater than those from the other three soils with AS and AN at the 20 to 29 oC temperature range and either 20% or 80% FC. The Ea values of NH3 emission from the WSL soil with AS, and AN were about 45 cal mol-1oC temperature range and 20% FC. The NH at 20 to 29 3 volatilization from the WSL soil was highly dependant on the temperature.
