福建省惠安县是一个水土流失严重的县份,以“地瓜县”而闻名省内外。惠安境内主要是花岗岩发育的土壤,母质结构疏松,土壤沙多泥少,涵蓄能力低,地力瘠薄,酸度大,所以地被物不易生长,一遇大风、暴雨,就引起严重水土流失。这里的气侯条件属亚热带地域,面临海洋,受季风影响大,形成半年干半年湿,4～9月特别是5～7月为绝对湿季。平均降雨量1025毫米,5、6、7月份 Huian County, Fujian Province, is a county with serious soil erosion and is famous both at home and abroad in the county of “sweet potato”. Huian territory is mainly granite soil, the parent material structure loose, mud and mud less soil, low storage capacity, infertility infertility, acidity, so the ground is not easy to grow, a case of gale, rain, causing serious soil erosion. The climatic conditions here belong to the subtropical region, face the ocean, affected by the monsoon, forming six months of dry wet, 4 to 9 months, especially from May to July as the absolute wet season. The average rainfall is 1,025 millimeters, 5,6,7 months