[Ammonia volatilization from rice field under different water conditions in lower Liaohe River Plain]

With ventilating chamber, this paper measured the ammonia volatilization from a meadow brown soil rice field after N fertilization under different water conditions in lower Liaohe River Plain. The results showed that there was an obvious ammonia volatilization after N fertilization. The total ammonia volatilization during rice growth period was 11.64-34.01 kg N x hm(-2), accounting for 4.66%-11.66% of applied N. The volatilization loss of applied N at different growth stages followed the order of tillering stage > booting stage > before transplanting, and the peak was appeared at 2-4 days after N fertilization. Field water condition had a strong effect on ammonia volatilization. Under waterlogging, both the amount of total ammonia volatilization and the percentage of lost fertilizer N were higher, and the ammonia volatilization rate increased with increasing N application rate, being significantly different among different N levels (P < 0.05). Under un-waterlogging, the ammonia volatilization was relatively low. N application rate and the ammonium concentration and pH in surface water were the main factors affecting ammonia volatilization, while P application rate had little effect when the N application rate was 180 kg N x hm(-2).