中文摘要：

岩石风化和土壤形成是地球表层物质循环的重要环节，了解岩石风化和土壤形成速率对土壤资源可持续利用和流域管理具有重要意义。本研究以位于我国亚热带的皖南花岗岩地区森林流域为例，通过野外监测其主要矿质元素输入输出量，应用流域中元素地球化学质量平衡原理，估算岩石风化和土壤形成速率。研究结果表明，在目前的降雨和酸沉降条件下，我国亚热带森林流域中，花岗岩的平均风化速率为0．696thm-2a-1，土壤平均形成速率为0．598thm-2a-1，所以需要经过2万年以上才能形成1m厚的土壤。研究发现，大量输入土壤系统的H’由于被土壤风化和阳离子交换所消耗，径流水不至酸化，但是从长远来看，这会带来土壤的酸化。研究还表明根据当前的土壤形成速率，土壤允许流失量标准需要重新制定。

英文摘要：

Rock weathering and soil formation are important links of element cycling in the earth surface. The knowl- edge of rock weathering and soil formation rates is important for sustainable utilization of soil resources and watershed man- agement. A typical forest watershed, located in South Anhui, subtropical China, was chosen as a case for study. Input and output of main mineral elements were monitored. Rock weathering and soil formation rates were estimated using the principles of geochemical mass balance of the elements in the watershed. Results show that with the current rainfall and acid precipitation, the average granite weathering rate is 0. 696 t hm-Z a-J and the soil formation rate is 0. 598 t hm-2 a-1. That is to say, it takes more than 20 000 years to form 1 meter of soil in this area. It was found that a large amount of H＋ was sunk into the ecosystem, but did not make stream water acidic because it was exhausted by soil mineral weathe- ring and cation exchange. However, in the long run, it will acidify the soil. The research also found that it is necessary to re-set criteria of soil loss tolerance on the basis of the current soil formation rate.