不同施氮量和施氮方式对稻田氨挥发损失的影响

采用密闭室法研究苏南地区稻麦轮作体系中,不同施N量和施N方式对水稻和小麦生育期氨挥发损失的影响。结果表明,优化施肥能明显降低稻-麦轮作系统中的氨挥发损失,在整个稻麦轮作体系中,优化和习惯的氨挥发损失占N肥施用量的百分比分别为7．05％±1.37％和9．81％±0．38％。稻季与麦季的氨挥发损失差异显著。稻季氨挥发损失量与N肥施用量呈乘幂关系上升,麦季则呈正的线性关系。水稻施肥后氨挥发持续的时间短,主要发生在施肥后1周以内,麦季持续时间较长,在施肥后10天左右。稻季和麦季的基肥阶段是主要的氨挥发时期,占各自氨挥发损失N的50％左右。

Effects of Rate and Method of N Application on Ammonia Volatilization in Paddy Fields

A continuous airflow enclosure chamber method was used to study ammonia volatilization from paddy field under the rice-wheat rotation system in South Jiangsu and effects of rate and method of nitrogen fertilizer application on ammonia emission from the field during the rice and wheat growing periods.Results showed that ammonia volatilization could be obviously reduced under the rice-wheat rotation system by optimizing fertilization,N loss through ammonia volatilization accounted for 7.05%±1.37% and 9.81%±0.38%,respectively,of the total N applied for optimized and traditional ways of fertilization.The difference in ammonia volatilization between the rice season (water-logged) and the wheat season (dry) was notable.During the rice season N loss through volatilization rose with the application rate of nitrogen fertilizer,showing a power relationship while during the wheat season,a linear relationship.In the rice field,ammonia volatilization lasted short,and took place within a week after N application,while in the wheat field,it lasted longer for about ten days.Almost 50% of the ammonia volatilization took place during the basal dressing period in either rice or wheat season.