花岗岩地区在我国南方分布总面积达23.9万km2,主要分布在广东、福建及广西东南部,长江流域的湖南、江西南部,安徽、湖北东部与西南部以及四川省局部地区。这些地区多数是丘陵、低山区,部分为中山、高山区,地面坡度陡,坡面破碎,表土层深厚或已出现母质层裸露,为降雨径流侵蚀提供 The total area of ​​granite area is 239,000 km2 distributed in southern China, mainly in Guangdong, Fujian and southeast of Guangxi, Hunan in the Yangtze River valley, southern Jiangxi, Anhui, eastern and southwestern Hubei and parts of Sichuan. Most of these areas are hilly and low mountainous areas, partly in the mid-mountains and high-mountain areas, steeply steep slopes, broken slope surfaces, deep overburden or exposed parent material, providing rainfall runoff erosion