Ammonia volatilization in gleyed paddy field soils of Taihu Lake region

An experiment was conducted under different amounts of fertilizer-N, straw and pig manure to study ammonia volatilization in gleyed paddy soils using continuous airflow method. Ammonia volatilization in 2005 and 2006 are 8.2～ 28.7kg/hm² and 21.8～62.1kg/hm² respectively, with NH₃ loss to applied fertilizer-N of 3.7％～8.8％ and 10.0％～18.9％, respectively. The highest ammonia volatilization loss occurs at top-dressing at tillering stage,while the lowest loss is at top-dressing at panicle stage. Ammonia volatilization mainly happens within three days after fertilization. Straw accelerates short term urea hydroxylation, but does not significantly increase ammonia volatilization. Pig manure slowly promotes ammonia volatilization,but increases ammonia volatilization. A strong correlation exists between ammonia volatilization and NH₄⁺-N concentration in surface water.