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利用静态暗箱法, 对内蒙古锡林河流域沿降水梯度4种半干旱草地类型进行了连续2年的野外定位试验, 对比研究了沿降水梯度4种不同草地类型土壤呼吸通量的变化特征, 统计分析了水热因子对草地土壤呼吸通量特征的可能影响, 并建立了土壤呼吸通量与水热因子间的数值关系模式, 同时利用野外连续完整的观测数据对不同草地类型土壤 CO2 年排放量分别进行了估算. 结果表明: 土壤呼吸通量存在明显的季节变化规律, 沿降水梯度各草地类型土壤呼吸通量的季节变化型式基本相同, 各草地群落土壤呼吸均以春末和夏季较高, 秋冬季排放量较低, 不同草地类型冬季均观测到土壤呼吸的负通量,对其机制的进一步研究有利于对土壤年呼吸总量的准确估算; 沿降水梯度 4 种草地类型土壤年(或生长季)呼吸量均沿降水梯度递减, 表现为贝加尔针茅草原>羊草草原>大针茅草原>克氏针茅草原; 不同草地类型土壤呼吸通量在植物生长季与0～10 cm 以及 10～20 cm 土壤含水量均呈不同程度的正相关, 而与气温和表层土壤温度的相关性较弱, 4 种草地类型生长季内土壤表层含水量的变化通常能解释土壤呼吸通量变异的 70.2%～94.7%, 而在植物非生长季, 土壤呼吸通量更多地受气温及土壤表层地温的限制, 温度条件的变化能解释土壤呼吸通量变化的 70%以上.
Using the static black box method, the field experiment of four semi-arid grassland types along the precipitation gradient in the Xilin River Basin of Inner Mongolia for two consecutive years was conducted. The characteristics of soil respiration flux in four different grassland types along the precipitation gradient were compared. The possible influence of hydrothermal factors on grassland soil respiration flux characteristics was analyzed and the numerical relationship between soil respiration flux and hydrothermal factors was established. At the same time, using the continuous and complete observation data in the field, The results showed that there was a clear seasonal variation pattern of soil respiration, and the seasonal variations of soil respiration fluxes were the same in all grassland types along the gradient of precipitation. Soil respiration of each grassland community was higher in late spring and summer, The autumn and winter emissions were lower, and the negative fluxes of soil respiration were observed in different grassland types in winter. Further study on its mechanism was conducive to accurate estimation of annual total amount of soil respiration. Growing season) respiration decreased along the gradient of precipitation, showed as Stipa baicalensis> Leymus chinensis> Stipa > Stipa krylovonia; soil respiration fluxes of different grassland types were positively correlated with soil moisture at 0 ~ 10 cm and 10 ~ 20 cm during the plant growing season, but were correlated with air temperature and surface soil temperature Weak, the change of soil surface water content in four types of grassland usually can explain 70.2% ~ 94.7% of the variation of soil respiration flux, while in the non-growing season, the soil respiration flux is more affected by temperature and soil surface temperature The change in temperature conditions can account for more than 70% of the change in soil respiration flux.