中文摘要：

利用中国第二次土壤普查确定的886个典型地带性土种剖面资料，通过统计分析研究了全国及6个地理区域（华东、华南、西南、东北、华北和西北）地带性土壤表层有机质含量与pH的关系。结果表明，土壤表层有机质含量和pH在不同地理区域间有明显差异；土壤有机质含量有随pH升高而降低的趋势，二者间呈极显著的负相关关系（r=-0．332～-0．530，P〈0．001），在控制温度、降雨和海拔条件下，二者间的偏相关关系也均达到l％的显著水平（r偏=-0．217～-0．322）；指数方程（SOM=a e^bpH，a和b为常数）可以较好地描述土壤表层有机质含量与pH的关系，土壤pH变异可以分别解释有机质含量总变异的12．2％～22．9％．

英文摘要：

Soil organic matter plays a key role in global carbon cycling and global climate changing. Relationships between organic matter （SOM） content and soil pH in topsoil of zonal soils of the whole country and six great geographical regions （i. e. Eastern, Southern, Northern, Northeastern, Northwestern and Southwestern China） were studied statistically based on the data of 886 soil profiles of zonal soil types defined during the second national soil survey of China. Results show that SOM content and soil pH varied significantly from one geographical region to another. There was obvious trend that SOM contents decreased with increasing soil pH, showing a significant negative correlation with soil pH （r = -0. 332～ -0. 530, p 〈 0. 001）. Partial correlation between them, with controlled annual mean temperature, annual mean precipitation and altitude, was also significant at 0.01 level （rp = -0. 217 - -0. 322）. An exponential equation （SOM = a e ^b pH, a and b were fit constants） can welt describe the relationship between SOM content and soil pH. The variance of soil pH is found to contribute 12.2%- 22.9% to the total variance of SOM content in the country and the six geographical regions.