荒漠化对毛乌素沙地土壤呼吸及生态系统碳固持的影响  

Effects of desertification on soil respiration and ecosystem carbon fixation in Mu Us sandy land

作　　者：丁金枝[1,2] 来利明[1] 赵学春[1] 朱林海[1] 姜联合[1] 郑元润[1] 

机构地区：[1]中国科学院植物研究所植被与环境变化国家重点实验室,北京100093 [2]中国科学院研究生院,北京100049

出　　处：《生态学报》2011年第6期1594-1603,共10页Acta Ecologica Sinica

基　　金：中国科学院知识创新工程重要方向项目(KZCX2-YW-JC303);国家自然科学基金项目(30671724)

摘　　要：荒漠化极大地影响着包括毛乌素沙地在内的干旱、半干旱区的土壤呼吸及碳固持潜力,因而,可能对区域或全球的碳循环造成一定影响。为揭示土壤呼吸的时间变化及其影响因子,理解荒漠化对毛乌素沙地土壤呼吸及碳固持的影响,根据毛乌素沙地荒漠化类型的研究结果,以毛乌素沙地固定沙地本氏针茅群落(FS)、固定沙地油蒿群落(FA)、半固定沙地油蒿群落(SFA)、流动沙地一年生植物群落(AL)等4个代表毛乌素沙地荒漠化主要阶段的植物群落为研究对象,采用LI-8100土壤碳通量测量系统测定了其土壤呼吸速率的日动态和月动态,结合植物群落生产力的野外调查,分析了荒漠化对土壤呼吸速率及碳固持的影响。结果表明:FA、FS、SFA、AL不同月份之间土壤呼吸速率日动态变化显著,4个群落5月份土壤呼吸最高、最低值分别出现在9:00-10:00和18:00,但6-9月份土壤呼吸最高、最低值却分别出现在12:00以后和7:00。FA、FS、SFA、AL在主要生长季(5-9月)的平均土壤呼吸速率分别为:99.79、88.13、47.95、13.82 mg.m-.2h-1。FS、FA和SFA土壤呼吸速率月变化显著,5月最低,7月最高,AL土壤呼吸速率月变化相对较小。FS、FA和SFA土壤呼吸速率月变化与土壤温度存在显著的指数相关关系,FS、FA、SFA和AL的Q10值依次为5.87、5.05、4.02、0.64。FS和FA的土壤呼吸速率月变化与土壤湿度显著正相关,而SFA和AL的土壤呼吸速率月变化与土壤湿度不存在显著线性关系。土壤呼吸与10 cm深度的土壤温度和湿度回归模型表明土壤温度和湿度可以解释不同群落土壤呼吸月变化的69%-87%。FS、FA、SF和AL的月土壤呼吸速率与根系生物量存在显著线性关系。在主要生长季(5-9月)平均根系呼吸速率和平均土壤微生物呼吸随荒漠化程度的加重而降低。FS、FA、SFA和AL根系呼吸与土壤呼吸的比率分别为51.40%、59.99%、70.85%、45.86%。在主要生�Desertification greatly affected the soil respiration and carbon fixation potential in arid and semi-arid area including the Mu Us sandy land of Northern China,and therefore changed the carbon circulation in regional or global scale.In order to reveal the temporal variations of soil respiration and their controlling factors,to understand the effect of desertification on soil respiration rate and the carbon fixation rate in Mu Us sandy land,the main desertification stages in this area were identified in this study as Stipa bungeana communities on fixed dunes（FS）,Artemisia ordosica communities on fixed dunes（FA）,A.ordosica communities on semi-fixed dunes（SFA） and annual grass communities in active dunes（AL） based on the previous researches.Within each of these communities,we measured the diurnal and monthly dynamics of soil respiration using a LI-8100 Automated Soil CO2 Flux System.In addition,we made field observations of the net primary productivity.The results showed that： Diurnal soil respiration rate varied significantly among different months in FS,FA,and SFA communities,but not for AL communities.For all communities,the highest soil respiration rates were observed in 9：00-10：00,and the lowest at 18：00 in May.However,the highest and the lowest values were observed after 12：00 and at 7：00 from June to September,respectively.In main growing season from May to September,the mean soil respiration rate were 99.79,88.13,47.95 and 13.82 mg·m-2·h-1 for FA,FS,SFA and AL communities,respectively.Monthly soil respiration changed significantly for FS,FA and SFA communities,but not for AL communities.Mean soil respiration rate was lowest in May and highest in July.An exponential relationship between monthly soil respiration of FS、FA and SFA communities and monthly temperature was found to be significant.The associated values of Q10 were 5.87,5.05,4.02,0.64,for FS、FA、SFA and AL communities,respectively.Monthly soil respiration was found to be linearly related to monthly soil moisture onl

关 键 词：毛乌素沙地 荒漠化 土壤呼吸速率 碳固持 

分 类 号：S154[农业科学—土壤学]