摘要
采用静态箱法研究了华北平原典型农田土壤N2O通量的日变化、季节变化特征,并分析土壤温度、水分对土壤N2O通量的影响。结果表明,在作物生长季节内,华北平原玉米田、大豆田、棉花田土壤的N2O平均通量分别为244.3±27.9、177.8±27.1和88.2±8.1mg·m-·2h-1。玉米田、大豆田和棉花田土壤N2O排放均呈明显的季节变化,苗期玉米田和大豆田、抽雄吐丝期玉米田及始花期棉花田土壤N2O的释放峰均由施肥所致,始花期大豆田土壤N2O的释放峰主要与大豆自身生理代谢活动及降水有关。玉米田土壤N2O通量的日过程为午后-凌晨双峰型,棉花田土壤N2O通量的日过程变化多样:有白天-夜间双峰型、白天或夜间单峰型、平缓型4种。观测到的土壤N2O排放的日变化类型主要受土壤湿度影响,随着土壤湿度降低,土壤N2O排放的日最高值从夜间转至白天,其日较差变小。玉米田、大豆田、棉花田土壤N2O排放通量均随地温增加呈指数增长,并都达到0.01显著水平。观测期间玉米田、大豆田、棉花田土壤N2O排放通量与土壤水分相关性均不显著。
Diumal and seasonal variation of soil N2O fluxes were measured using close chamber method in typical crop fields in North China Plain. The influence of soil temperature and moisture on soil N2O flux was also discussed. The results showed that soil N2O fluxes in maize, soybean and cotton fields were 244.3±27.9, 177.8±27.1 and 88.2±8.1 mg·m^-2·h^-1 respectively during growing season. Seasonal variation of soil N2O flux was obviously in maize, soybean and cotton field. The peaks of soil N2O emission in maize and soybean field at seedling stage, maize field at blooming stage, and cotton filed at early blooming stage all resulted in fertilization. The peak of soil N2O emission in soybean field at early blooming stage was mainly related to soybean metabolism and precipitation. Double-peak shaped diurnal soil N2O flux was shown in the maize field. One peak appeared in daybreak and another in afternoon. Four kinds of diurnal variation of soil N2O flux were found in the cotton field： double-peaks （daytime and nighttime）, single-peak （daytime or nighttime） and no peak shaped diurnal variations. Moisture is the main factor controlling observed diurnal variation of soil N2O emission. While soil moisture decreased, the appearance of peak of diurnal soil N2O flux changed from nighttime to daytime and the diurnal range of soil N2O flux was small. In maize, soybean and cotton fields, soil N2O emissions increased exponentially with soil temperature. But no correlation was found between N2O fluxes and soil moisture during the observation period.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2005年第6期1186-1191,共6页
Journal of Agro-Environment Science
基金
国家973计划(2002CB412501)
中国科学院知识创新工程重大项目(KZ-CX-SW-01-01B)
关键词
土壤N2O排放
华北平原
棉花田
玉米田
大豆田
土壤温度
soil N2O emission
North China Plain
cotton field
maize field
soybean field
soil temperature
