中文摘要：

以腾格里沙漠东南缘自然植被区生长的两种典型生物结皮——藓类和藻类-地衣混生结皮覆盖土壤为对象,通过设置0（对照）、1 mm（浅层）和10 mm（深层）沙埋处理,研究了沙埋对该区结皮覆盖土壤温室气体通量的影响,并通过测定沙埋后土壤温度、水分的变化,初步探讨了沙埋影响生物结皮覆盖土壤温室气体通量的环境机制.结果表明：沙埋显著增加了两类结皮覆盖土壤的CO2释放通量和CH4吸收通量（P〈0.05）;但对N2O通量的影响因沙埋厚度和结皮类型的不同而异：深层沙埋（10 mm）显著增加了两类结皮覆盖土壤的N2O吸收通量,浅层沙埋（1 mm）仅显著降低了藓类结皮覆盖土壤的N2O吸收通量,而对混生结皮覆盖土壤的N2O通量影响不显著.沙埋显著增加了两类结皮覆盖土壤的表层温度和05 cm深土壤湿度,从而增加了其CO2释放通量.但是沙埋引起的土壤温湿度的变化与CH4和N2O通量变化的相关性不显著,说明沙埋引起的土壤温湿度变化不是影响其CH4和N2O通量的关键因子.

英文摘要：

Based on the measurements of the fluxes of CO2,CH4 and N2O from the soil covered by two types of biocrusts dominated separately by moss and algae-lichen,followed by 0（ control）,1（ shallow） and 10（ deep） mm depths of sand burial treatments,we studied the effects of sand burial on greenhouse gases fluxes and their relationships with soil temperature and moisture at Shapotou,southeastern edge of the Tengger Desert. The results showed that sand burial had significantly positive effects on CO2 emission fluxes and CH4 uptake fluxes of the soil covered by the two types of biocrusts,but imposed differential effects on N2O fluxes depending on the type of biocrust and the depth of burial. Deep burial（ 10 mm） dramatically increased the N2O uptake fluxes of the soil covered by the two types of biocrusts,while shallow burial（ 1 mm） decreased the N2O uptake flux of the soil co-vered by moss crust only and had no significant effects on N2O uptake flux of the soil covered by algae-lichen crust. In addition,CO2 fluxes of the two biocrusts were closely related to the soil temperature and soil moisture,thereby increasing with the raised soil surface temperature and soil moisture caused by sand burial. However,the relationships of burial-induced changes of soil temperature and moisture with the changes in the other two greenhouse gases fluxes were not evident,indicating that the variations of soil temperature and moisture caused by sand burial were not the key factors affecting the fluxes of CH4 and N2O of the soil covered by the two types of biocrusts.