湖南典型双季稻田氨挥发对施氮量的响应研究

选择湖南典型双季稻田为对象，采用密闭室连续抽气法研究了不同施氮量下的氨挥发损失。结果表明，稻田氨挥发总量随施氮量增加而显著增加，在当地农民习惯施肥水平（早稻150 kg/hm2、晚稻180 kg/hm2）下，早稻氨挥发损失氮量占施氮量的39.8%，晚稻则达46.9%，双季稻平均氨挥发损失率达43.7%。氨挥发通量与田面水的NH+4-N浓度和 pH 之间均存在极显著的正相关关系。可见，氨挥发是该区域稻田氮素损失的最主要途径之一。

Responses of ammonia volatilization to nitrogen application amount in typical double cropping paddy fields in Hunan Province

Typical double cropping paddy field in Hunan Province and a closed continuous airflow method was used to study on dynamic changes of ammonia volatilization in treatments with different nitrogen (N) application amount. The result showed that total amount of ammonia volatilization was increased significantly with increasing of N application amount. N lost in ammonia volatilization of early rice field was account for 39.8% of N application amount, and lost 46.9% in late rice field, the average lost ratio of ammonia volatilization in double cropping paddy fields was 43.7%. The ammonia volatilization fluxes were significant positively correlated withNH+4-N concentration and pH value in surface water of paddy filed respectively. The results indicated that ammonia volatilization is a main approach to lose of N in paddy fields of Hunan Province.