三江平原典型土地利用类型土壤呼吸强度对温度的敏感性

采用实验室恒温培养方法对三江平原3种不同土地利用类型开发后的沼泽土和草甸土进行了温度敏感性研究。研究结果表明，在5℃、15℃、25℃和35℃ 4种不同温度条件下，各土壤类型的土壤呼吸速率均随温度的升高而增大。在同一温度条件下，3种土壤呼吸强度由弱到强依次是：草甸土-旱地<草甸土-水田<沼泽土-人工林。指数模型和乘幂模型均可以较好地描述沼泽土和草甸土土壤呼吸与温度之间的关系，土壤呼吸强度随温度的升高呈指数或乘幂上升。3种土壤的Q10值呈现出随温度升高而降低的趋势，表明土壤呼吸在较低温度下的温度敏感性更高。对未添加植物残体的纯土壤组和添加了植物残体的对照组进行对比研究，发现添加植物残体后土壤呼吸强度大大增强，因此野外实际的土壤呼吸强度要比通常室内实验中去除植物残体后所测定的土壤呼吸强度更高。

Temperature sensitivity of soil respiration from the typical land-use types in the Sanjiang Plain,northeastern Heilongjiang Province

Temperature sensitivity of soil respiration of the samples from different land-use types in the Sanjiang Plain was studied using the laboratory incubation method. The results show that, at four different temperature conditions of 5 ℃, 15 ℃, 25 ℃ and 35 ℃, soil respiration rates of all the soil types increase with the increasing temperature. Under the same temperature condition, the three types of soils are in order of increasing respiration intensities of meadow soil-dry land < meadow soil- paddy field < bog soil- plantation. Both of the exponential model and the power model can be used to describe the relationship between soil respiration and temperature of the soils, which means that soil respiration intensity increases exponentially or as power function with the increasing temperature. The Q10 values of the three kinds of soils show a trend of decreasing with increasing temperature, which suggests that the temperature sensitivity of soil respiration is higher at the lower temperature. By the comparative incubation experiments on the pure soil without plant residues and the control group with plant residues, the authors found that soil respiration is greatly enhanced with additional plant residues, so the actual soil respiration in the field is higher than that measured in the laboratory in which plant residues are usually removed.