生物结皮对内蒙古沙地灌丛草地土壤呼吸特征的影响

利用静态暗箱法分析生物结皮对内蒙古典型油蒿沙地灌丛草地土壤呼吸变化特征及水热敏感性影响。结果表明:生物结皮(BSC)与裸地(BG)土壤呼吸速率表现出类似的季节变化动态,BSC土壤呼吸年内变异系数约66.6%~81.7%,高于同期BG的50.9%~76.5%,其年际变异(22.4%)远大于BG(8.0%);BSC生长季土壤呼吸总量约126.88~186.07 gC/m²,显著高于BG(91.22~100.90 gC/m²)(p<0.05);BSC土壤呼吸对表层土壤水分变化的响应较BG更敏感,两个年份生长季BSC与BG表层0~10 cm土壤含水量变化分别能够解释土壤呼吸变异的81.3%,53.2%,57.8%以及55.4%。

Effects of Biological Soil Crust on Soil Respiration Characteristics in Sandy Shrubland in Inner Mongolia,China

A two-year field experiment was carried out in Artemisia ordosica sandy shrubland in the Ordos Plateau of Inner Mongolia, China, in 2006-2007 using a static opaque chamber with an infrared CO₂ gas analyzer technique. The effects of biological crust on the main characteristics of soil respiration and its sensitivity to the change of water-heat factors were analyzed. The results indicated that similar seasonal dynamic was found in the BSC and BG. The coefficients of variation (CVs) for soil respiration of BSC in different growing seasons ranged from 66.6% to 81.7%, higher than those of BG, which were in the range of 50.9%-76.5% for the same period, and the inert-annual CV of BSC (22.4%) was also higher than that of BG (8.0%). The existence of biological crusts enlarged the annual and inter-annual variation in soil respiration. The total soil respiration of different growing seasons for the BSC treatment were 126.88-186.07 g C/m², significantly higher than those of 91.22-100.90 g C/m² for the BG treatment. In the growing season, the soil respiration rates were significantly related to surface soil water contents, and the change of soil respiration rate was more sensitive to that of soil water contents in BSC than in BG for the two measured years. 81.3%, 53.2%, 57.8% and 55.4% of variation in soil respiration could be explained by the change in 0-10 cm soil water content for BSC and BG treatments in the two years, respectively.