作 者 ：张义辉,李洪建*,荣燕美,严俊霞,李君剑
期 刊 ：生态学报 2010年 30卷 23期 页码：6606~6612
关键词：土壤呼吸；空间异质性；地统计学；半方差分析；太原盆地；
Keywords:soil respiration, spaial heterogeneity, geostatistics, semivariance analysis, Taiyuan basin,
摘 要 ：土壤呼吸不仅存在时间上的变化，而且也具有明显的空间变化特征。土壤呼吸的时、空变化增加了土壤呼吸测定的不确定性。研究土壤呼吸的空间异质性是准确估算区域土壤呼吸的基础。通过2008年7、9、11月对太原盆地39个样地的土壤呼吸以及土壤温度和土壤水分等环境因子进行测定的基础上，用传统和地统计学的方法对太原盆地土壤呼吸以及环境因子的空间异质性进行了分析。传统统计（描述统计）分析结果表明：3次土壤呼吸的平均值分别为（7.8±3.3）、（8.9±4.0）和（21±1.3）μmol CO2 m-2 s-1，变异系数分别为42%，44%和59%，属于中等变异；采用地统计学的半方差函数进行分析结果表明：球状模型能很好地反映土壤呼吸和土壤水分的空间结构特征，3次土壤呼吸和土壤水分的C0/(C0+C)值分别为0.004、0038和0.005以及0.011、0.003和0.003，表明土壤呼吸和土壤水分表现出高度的空间自相关性，其空间变异主要是由结构性因素引起；3次土壤呼吸和土壤水分半方差函数的变程分别为190、370 m和510 m以及90、140 m和220 m，说明影响土壤呼吸和土壤水分的生态过程随时间变化在不同尺度上起作用；3次土壤呼吸的分维值分别为0.634、0.965和0.763，表明7月份土壤呼吸的空间依赖性最强，11月份次之，9月份最弱，与半方差函数的分析结果相吻合。用Kriging插值法绘制的土壤呼吸等值线图进一步表明土壤呼吸具有高度的空间异质性，这异质性主要是由于土壤水分不同所造成。
Abstract:Soil respiration varies not only in time but also in space. These temporal and spatial variations increase uncertainties in soil respiration measurements. Understanding the spatial and temporal variation in soil respiration of a region is fundamental for an accurate estimation of CO2 emission in the region. Based on the field measurements of soil respiration and some other environmental factors such as soil temperature and soil water content at 39 sites in Taiyuan basin in July, September and November 2008, we analyzed heterogeneous soil respiration and its relation to other environmental factors using both traditional and geostatistics methods. The traditional statistical analysis (descriptive statistics) showed that the averages of soil respiration rate were (7.8±3.3), (8.9±4.0) and (2.1±1.3)μmol CO2 m-2s-1, respectively, for July, September and November. The coefficients of variation were 42%, 44% and 59%, respectively, indicating that spatial variation of soil respiration in this area was moderate. When semivariance analysis of geostatistics was used, the results showed the semivariograms of soil respiration rate could well be described by a spherical model. The C0/(C0+C) values for July, September and November were 0.004, 0.038 and 0.005 respectively for soil respiration, and 0011, 0003 and 0.003 respectively for soil moisture, indicating that spatial heterogeneities of both soil respiration and soil water content were resulted mainly by structural factors. The ranges of semivariogram function of the 3 measurements were 190, 370 and 510 m respectively for soil respiration, and 90, 140 and 220 m respectively for soil moisture. The results indicated that the ecological progresses were influencing soil respiration and soil moisture which changed with time at different scales. The fractal dimension values of soil respiration for the measurements of July, September and November were 0.634, 0.965 and 0.763, respectively, indicating that the strongest spatial dependence of soil respiration is in July followed by November and the weakest is in September, in good agreement with the semi-variogram analysis.. The isoline map of soil respiration rates produced with the Kriging interpolation method showed that there was high spatial heterogeneity of soil respiration which was mainly caused by the differences in soil water content.
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