大针茅典型草原土壤CO2排放规律的研究

采用静态室/碱吸收法研究了内蒙古大针茅典型草原土壤呼吸的时空动态.大针茅群落地上部和地下部生物量的时空变异不同步,用地上部生物量不能很好地预测群落的根系量.群落土壤呼吸具有明显的时空动态,控制群落土壤呼吸空间变异与时间变异的因子是不同的.土壤呼吸的季节变化与地上部生物量及土壤水分状况关系密切.根据大针茅群落分别计算了大针茅群落1995、1997和1998年的年CO₂排放总量,分别为180、45.8和225gC·m^-2·a^-1,年际变异很大.过度放牧大大降低了群落的生物量,也降低了土壤CO₂排放量.讨论了建立以降水量为驱动因子的草地群落土壤呼吸动态模型的可能性.

CO2 release from typical Stipa grandis grassland soil

Determinations on the soil respiration in a typical Stipa grandis grassland of Inner Mongolica by the method of static chamber/alkaline absorbing show that there existed great spatial and temporal variances of soil respiration, and the factors controlling these variances were different. The seasonal variance of soil respiration had a close relationship with the aboveground biomass of S. grandis and the status of soil moisture. The total amount of annual CO2 release in 1995, 1997 and 1998 was estimated as 180, 45.8 and 225 gC.m-2.yr-1, respectively. Overgrazing greatly decreased the biomass of the community, and also, decreased the CO2 release from the soil. The possibility of establishing a dynamic model of soil respiration in grassland with precipitation as a driven factor was discussed.