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利用Li-6400-09系统,对我国亚热带地区3种主要林分类型(常绿阔叶林、杉木林和毛竹林)的土壤呼吸和土壤温、湿度进行了野外测定,并采用多种模型对土壤呼吸与土壤温、湿度的关系进行拟合.结果表明:毛竹林、常绿阔叶林和杉木林的土壤呼吸碳通量分别为12.84、11.70和7.12tC.hm-2.a-1;3种林型土壤呼吸具有相似的时间变化格局,其日变化均在11:00—12:00达到峰值,1:00—3:00最小;季节变化中,7、8月达到峰值,12月和翌年1月最小;Van′tHoff模型和LloydandTaylor方程在描述土壤呼吸与土壤温度的相关性时差异不大,但LloydandTaylor模拟得出的土壤呼吸值小于实测值;二次项模型和幂函数模型能较好地模拟土壤呼吸与含水量的关系,土壤含水量对土壤呼吸具有双向调节作用,但只有杉木林二者相关性达到显著水平;土壤水热双因子模型比单因子模型能更有效地描述土壤呼吸对土壤温、湿度协同变化的响应特征;协方差分析消除土壤温度、土壤含水量的影响后,植被类型对土壤呼吸的影响达到显著水平(R2=0.541);空气温度、空气相对湿度和光合辐射也在不同程度上影响着土壤呼吸变化,且空气温度的影响达到显著水平.
Using Li-6400-09 system, the soil respiration and soil temperature and humidity of three main stand types (evergreen broadleaf forest, Chinese fir forest and Phyllostachys pubescens forest) in the subtropical region of China were measured in the field. Soil respiration and soil temperature and humidity were fitted.The results showed that the soil carbon respiration was 12.84, 11.70 and 7.12tC.hm-2.a-1 respectively in Moso bamboo forest, evergreen broadleaved forest and Chinese fir forest, The soil respiration of the three forest types all had the similar temporal pattern. The diurnal variations of the soil respiration peaked at 11: 00-12: 00 and the minimum at 1: 00-3: 00. In the seasons, the peak was reached in July and August, And the minimum in January of next year. The Van’tHoff model and the Lloyd and Taylor equation are similar in describing the correlation between soil respiration and soil temperature, but the soil respiration values obtained by Lloyd and Taylor simulation are less than the measured values. The quadratic term model and power function model The relationship between soil respiration and water content was better simulated, and the soil water content had a two-way regulation on soil respiration, but only the correlation between the two Chinese fir forests reached a significant level. The two-factor model of soil hydrothermal could be described more effectively than the single factor model Soil respiration on the soil temperature and humidity (R2 = 0.541). The air temperature, air relative humidity and photosynthetic radiation were also affected to a certain extent (R2 = 0.541) .According to the covariance analysis, the influence of soil temperature and soil water content on the soil respiration was significant Affecting soil respiration changes, and the impact of air temperature reached a significant level.