沙丘差巴嘎蒿(Artemisia halodendron)群落与裸地土壤呼吸特征

沙丘差巴嘎蒿(Artemisia halodendron)群落与裸地的土壤呼吸是荒漠生态系统碳循环的重要过程。运用LI-6400土壤呼吸配套系统对科尔沁半流动沙丘差巴嘎蒿群落与裸地土壤呼吸进行测定,分析了沙丘差巴嘎蒿群落与裸地土壤呼吸的日、季变化及其影响因子。结果表明:(1)沙丘差巴嘎蒿群落与裸地土壤呼吸的日变化,夜间显著高于昼间(P<0.01和P<0.05),且呈多峰型,与空气湿度呈显著的幂函数正相关(P<0.05)。(2)土壤呼吸的季变化,除重度干旱胁迫的7月7日、19日以外,其余观测日均为差巴嘎蒿群落显著高于裸地(P<0.01)。(3)土壤呼吸的季变化与土壤温度相关不显著(P>0.05),但在控制测试日土壤含水量的条件下,沙丘差巴嘎蒿群落与裸地土壤呼吸和土壤温度的偏相关显著(P<0.05),偏相关系数分别为0.602与0.562;在控制测试日土壤温度的条件下,沙丘差巴嘎蒿群落与裸地土壤呼吸和土壤含水量的偏相关显著(P<0.05),偏相关系数分别为0.804与0.624。土壤表层(10 cm深处)细菌数量与土壤呼吸呈极显著的幂函数正相关(P<0.01),可解释沙丘差巴嘎蒿群落与裸地土壤呼吸变化的80.8%与65.4%。

Variation of Soil Respiration Rate and the Influencing Factors in Artemisia halodendron Habitats and Bare Land

Soil respiration of Artemisia halodendron habitats and bare land is an important process of the carbon cycle in desert ecosystems. In this article, the soil respiration in Horqin semi-mobile dune was determined by using li-6400 soil respiratory system, the diurnal(24 h), seasonal variation, influencing factors and their differences were analyzed. The results showed that:(1) the diurnal variation of soil respiration rate in dune was multimoda, the respiration rate of the night soil was higher than that of the daytime soil, the diurnal variation of soil respiration in dune was positively correlated with the obvious power function of air humidity.(2) except on the July 7 and 19, the seasonal changes of the soil respiration rate was higher in A. halodendron habitat than bare land.(3) A. halodendron and bare land soil respiration were significantly correlated to soil temperature(P<0.05), the correlation coefficient is 0.602 and 0.562, respectively. A. halodendron and bare land soil respiration were also significantly correlated to soil moisture content(P<0.05), the correlation coefficient is 0.804 and 0.624, respectively. The quantitative analysis showed that the number of bacteria in soil surface(in the depth of 10 cm) was significantly related to soil respiration(P<0.01), it could explain 80.8% and 65.4% of soil respiration in A. halodendron and bare land, respectively.