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采用LI-8100土壤CO2通量测量系统,对山西太岳山马泉林场不同择伐强度的幼龄油松人工林生长季土壤总呼吸速率、土壤分室呼吸速率及5 cm深处的土壤温度、湿度进行观测,研究了择伐后林地土壤呼吸的特征,分析了土壤呼吸影响因素,探讨了土壤呼吸对森林经营措施的响应。研究表明:1)择伐后不同采伐强度样地土壤呼吸速率值均大于对照样地,各样地土壤呼吸速率峰值均出现在8月份,择伐增强了土壤CO2的排放,且择伐强度越大,土壤CO2排放越强;2)择伐导致林地土壤水热条件的变化是土壤呼吸改变的重要原因之一,双因子模型拟合表明,土壤温湿度共同解释了土壤呼吸速率的60.5%~79.8%;3)择伐后枯枝落叶层呼吸和根呼吸的变化是土壤呼吸变化的重要组分,矿质土壤呼吸的变化不显著。在生产实践中,应采用20%的择伐强度,以减小林地土壤表面CO2通量的增量。
LI-8100 soil CO2 flux measurement system was used to measure the total soil respiration rate, soil compartment respiration rate and soil temperature and humidity at the depth of 5 cm during the growth season of young pine plantations of Mazu Forestry Farm with different cutting strengths in Taiyue Mountain, Shanxi. Observed the characteristics of forest soil respiration after selective cutting, analyzed the influencing factors of soil respiration, and discussed the response of soil respiration to forest management measures. The results showed that: 1) The soil respiration rates of different cutting densities after selective cutting were higher than those of the control plots. The peak values of soil respiration rate occurred in all plots in August. Selective cutting enhanced the soil CO2 emission, The soil CO2 emission is stronger; 2) the change of soil moisture and heat condition caused by selective cutting is one of the important reasons for the change of soil respiration. The two-factor model fitting shows that the soil temperature and humidity together explain 60.5% 79.8%. 3) The changes of respiration and root respiration in the litter layer after senescing were the important components of soil respiration. The changes of respiration in mineral soils were not significant. In production practice, 20% of the selective cutting intensity should be used to reduce the increment of CO2 flux on the soil surface of forest land.