农垦对温带草地生态系统CO_2、CH_4、N_2O通量的影响  

Impat of Reclamation of Grassland on the Fluxes of CO_2, CH_4 and N_2O in Temperate Grassland Ecosystem

作　　者：李明峰[1] 董云社[1] 齐玉春[1] 耿元波[1] 

机构地区：[1]中国科学院地理科学与资源研究所,北京100101

出　　处：《中国农业科学》2004年第12期1960-1965,共6页Scientia Agricultura Sinica

基　　金：中国科学院知识创新重大项目(KZCX1-SW-01-04);国家重点基础研究发展规划项目(2002CB412503);中国科学院地理科学与资源研究所知识创新项目(CXIOG-E01-03-01与CXIOG-A00-06);国家自然科学基金项目(49971005)

摘　　要：2001年6～9月,利用静态暗箱法对内蒙古锡林河流域草甸草原及其开垦后的农田(春小麦)和休耕地的CO2、CH4和N2O的通量进行了野外实地观测。结果显示,草甸草原开垦为耕地对温带草地生态系统CO2、CH4和N2O源汇状况影响显著。从CO2排放量的平均值来看, 农田(545.8 mg穖-2穐-1)>草甸(301.9 mg穖-2穐-1)>休耕地(74.4 mg穖-2穐-1),其中草甸开垦为农田使CO2的排放增加了81%;在春小麦的生长期内,麦田的CO2排放量是草甸草原的2倍多,小麦死亡和收割后CO2排放锐减,可见农垦明显促进了CO2的排放。另外干旱使得草甸草原、农田和休耕地的CO2排放量表现出减少趋势。草甸开垦为农田后CH4吸收特征表现明显,但干旱减弱了其吸收趋势。就N2O而言,草地开垦后春小麦的种植总体上并未增加N2O的排放,只是改变了其排放特征;除小麦苗期外,N2O的排放都高于草甸草原;极端干旱还导致土壤对大气N2O的吸收。另外,农田的CH4吸收与N2O排放之间还存在此消彼长的关系。Using dark enclosed chamber technique, the fluxes of CO2, CH4 and N2O from meadow, cropland (spring wheat), the cultivated meadow, and fallow land in Xilin River Basin of Inner Mongolia were measured during the period from June to September in 2001. The results showed that the impact of cultivation of meadow on the fluxes of CO2, CH4 and N2O from it was very distinct. On an average of the emissions of CO2, CO2 fluxes from meadow, cropland and fallow land were 545.8, 301.9 and 74.4 mg穖-2穐-1, respectively, i.e. cropland>meadow>fallow. And the emission of CO2 increased by 81% after the cultivation of meadow. During the growth period of spring wheat, the emissions of CO2 from spring wheat field were more than two times as much as that from meadow. After the death or harvest of spring wheat, the flux of CO2 from cropland decreased sharply. Therefore, it is concluded that cultivation of meadow promoted the emissions of CO2. It was also found that the drought in 2001 cut the emissions of CO2 down seriously. The absorption of CH4 was accelerated significantly after meadow was changed into cropland not only in wheat field but also in fallow, and the trend of absorption became more obvious. But the strength of absorption of CH4 was weakened by the drought. As for the flux of N2O, it did not increase distinctly on the average during the planting season after spring wheat planting but the character of N2O emission from meadow was changed. The emissions of N2O from cropland were more than those from meadow during the period of rapid growth of spring wheat. And drought resulted in the absorption of N2O. In addition, the N2O emission increased with the decrease of absorption of CH4 in wheat field.

关 键 词：草甸草原 农田 春小麦 草地生态系统 温带 开垦 干旱 CO2排放量 CH4 通量 

分 类 号：S812[农业科学—草业科学] S512[农业科学—畜牧学]