艾比湖流域土壤呼吸日变化及水热因子影响

为研究干旱区植物群落土壤呼吸日变化特征及影响因子,利用开路式土壤碳通量测量系统LI-8100测定艾比湖流域四种植物群落土壤呼吸速率日变化,结合实测的温度、湿度因子,分析土壤温度、湿度,大气温度、空气相对湿度对土壤呼吸速率的影响。结果表明:胡杨、梭梭、芦苇、盐节木四种群落土壤呼吸速率日变化基本都呈单峰曲线。在日时间尺度上,胡杨群落、梭梭群落、盐节木群落、芦苇群落土壤呼吸速率与地上10和150 cm高度处气温均表现为显著正相关。各群落土壤呼吸速率与不同深度土壤温度并没有固定的相关关系。不同的植物群落,对土壤呼吸起首要作用的温度因子不相同,且气温通过土壤温度对土壤呼吸的间接影响不相同。可用一元或二元线性函数来描述温度与土壤呼吸速率关系。各群落的土壤呼吸速率与地上10和150cm处空气相对湿度均呈显著负相关。在日变化尺度上,土壤温度、土壤湿度、气温、空气相对湿度共同影响了土壤呼吸速率,由温度和湿度共同拟合出的模型能解释土壤呼吸速率变化78%以上的原因。

Research on Soil Respiration of Different Plant Communities in Ebinur Lake Basin

In this paper,the LI-8100 automated soil CO2 flux system was used to observe the soil respiration rate SRR of four plant communities in Ebinur Lake Basin,and the temperature and humidity factors were observed at the same time,which aims to analyze the changing feature of daily SRR and the influence of soil temperature,soil moisture,air temperature and relative humidity on the soil respiratory rate in arid regions.The results show that the day changes of SRR of the four plant communities present as unimodal curve.Based on daily time change law,the SRR of the four plant communities were positively correlated with air temperature,and there was no uniform correlativity between the SRR and soil temperature.The temperature factors,which play a leading role,changes with the type of plant communities.The indirect effect of air temperature on soil temperature was different.The quantitative relation between SRR and temperature can be described with linear function of one and two variables.There were significant negative correlations between SRR of different communities and air relative humidity.Based on daily time change law,the soil temperature,soil moisture,air temperature and air relative humidity play a role in SRR,and the regression model fitted by temperature and moisture can explain 78% of the changes of SRR.