内蒙古羊草草原呼吸的影响因素分析和区分  

Analysis of Affecting Factors and Partitioning of Respiration in a Leymus chinensis Steppe in Inner Mongolia

作　　者：耿元波[1] 罗光强[1,2] 

机构地区：[1]中国科学院地理科学与资源研究所,北京100101 [2]中国科学院研究生院,北京100049

出　　处：《地理学报》2010年第9期1058-1068,共11页Acta Geographica Sinica

基　　金：中国科学院地理科学与资源研究所自主创新项目(200905009);"十一五"国家科技支撑计划(2006BAJ10B04)~~

摘　　要：利用静态暗箱-气相色谱法在植物生长旺季测算了内蒙古锡林河流域羊草草原的土壤微生物呼吸、土壤呼吸和生态系统呼吸。地温和水分是植物生长旺季呼吸最重要的影响因素。地温在水分条件适宜的情况下可以解释CO2通量的部分变化(R2=0.376～0.655)。土壤水分含量也可以解释土壤呼吸和生态系统呼吸的部分变化(R2=0.314～0.583),但基本不能解释土壤微生物呼吸的变化(R2=0.063)。即使在较高温度下,较低的土壤水分含量(≤5%)也会显著的抑制CO2排放。长期干旱后降雨使CO2通量在高温下迅速增大。基于5cm地温和0～10cm土壤水分含量的双变量模型可以解释CO2通量约70%的变化。观测期间,土壤呼吸占生态系统呼吸的比例介于47.3%～72.4%之间,平均为59.4%;根呼吸占土壤呼吸的比例介于11.7%～51.7%之间,平均为20.5%。由于植物体去除引起的土壤水分含量上升可能使我们对土壤呼吸占生态系统呼吸比例的估计略微偏高,根呼吸占土壤呼吸的比例略微偏低。Using a static opaque chamber method,the rates of soil microbial respiration,soil respiration,and ecosystem respiration were measured through continuous in-situ experiments in semiarid Leymus chinensis steppe in Xilin River Basin of Inner Mongolia,China.Soil temperature and moisture are the most important factors affecting CO2 flux.Soil temperature was the main factor influencing respiration rates.Exponential models based on soil temperature can explain large percent of CO2 efflux variations（R2 = 0.375-0.655） excluding data of low soil water conditions.Soil moisture can also effectively explain some variations of soil and ecosystem respiration（R2 = 0.314-0.583）,but it can not explain much of variation of soil microbial respiration（R2 = 0.063）.Low soil water content（≤5%） inhibited CO2 efflux though soil temperature was high.Rewetting the soil after a long drought resulted in substantial increases in CO2 flux at high temperature.Bi-variable models based on soil temperature at 5 cm depth and soil water content at 0-10 cm depth can explain about 70% of variations of CO2 effluxes.The contribution of soil respiration to ecosystem respiration averaged 59.4%,ranging from 47.3% to 72.4%;the contribution of root respiration to soil respiration averaged 20.5%,ranging from 11.7% to 51.7%.The contribution of soil to ecosystem respiration was a little overestimated and root to soil respiration underestimated because ofincreased soil water content that occurred as a result of plant removal.

关 键 词：羊草草原 生态系统呼吸 土壤呼吸 土壤微生物呼吸 内蒙古 

分 类 号：S812[农业科学—草业科学]