Abstract: Ammonia volatilization from doublerice cropping field in red paddy soil was determined in a closed airflow chamber under different fertilization systems. Ammonia volatilization under different fertilization systems exhibited a similar trend, with a peak 1-3 days after fertilization and a subsequent decline, and almost no emission after a week. Ammonia volatilization rate increased with fertilizer application rate. During the early rice growth, the accumulation of N loss via ammonia volatilization after fertilization was 1.6-3.6 kg/hm2 for basal fertilizer and 5.8-18.2 kg/hm2 for fertilizer topdressed at the tillering stage, and during the late rice growth, the accumulation of N loss via ammonia volatilization was 45-7.9 kg/hm2 for basal fertilizer, 12.3-26.8 kg/hm2 for fertilizer todressed at the tillering stage and 1.4-2.4 kg/hm2 for fertilizer topdressed at the panicle initiation stage. The total accumulation in the early and the late rice growth period occupied 4.5%-15.3% and 16.9%-32.8% of the total of fertilizer application, respectively. Compared to the control, urea application could promote ammonia volatilization, and more N was lost through ammonia volatilization under the conditions of equal N application and zero P application. The supplement of more rice straw and green manure also showed a positive relationship with ammonia volatilization, so did NH4+N concentration, water pH and climate conditions(light, temperature and rainfall etc.).

Key words: fertilization system, doublecropping rice, ammonia volatilization, red soil, nitrogen fertilizer

摘要： 为系统地了解不同施肥制度下各生育期氨挥发损失的程度及规律，采用密闭室法对南方红壤地区双季稻田的氨挥发进行了监测。不同施肥制度下氨挥发的变化规律基本相同，施肥后1~3 d内达到峰值，随后逐渐下降，1周后无明显排放。氨挥发速率随施N量增加而增加。早季各处理氨挥发累积量基肥时为1.6~3.6 kg/hm2，分蘖肥时为58~18.2 kg/hm2；而晚季基肥、分蘖肥和穗肥时的氨挥发累积量分别为4.5~7.9、12.3~26.8和1.4~2.4 kg/hm2，早、晚季氨挥发总累积量分别占其施N量的4.5%~15.3%和16.9%~32.8%。相对于不施肥处理，尿素的施用促进氨挥发，而在等氮施用量下，缺P处理通过氨挥发损失的N量较多，较高水平的秸秆和绿肥施用也会增加氨挥发量。此外，氨挥发与田面水NH4+N浓度及水层pH之间存在正相关关系，气候条件也显著影响氨挥发量。

关键词: 施肥制度, 双季稻, 氨挥发, 红壤, 氮肥