闽西典型红壤区降雨侵蚀力变化特征研究

Study on the Characteristics Rainfall Erosivity Changes of the Typical Red Soil Region in Western Fujian

闽西典型红壤区土壤侵蚀较为严重,尤其是长汀、宁化等县,属国家级水土流失重点治理区。以闽西地区1980—2009年10个站点的降雨资料为基础,计算其降雨侵蚀力R值,研究了该区域降雨侵蚀力的时空分布特征。结果表明:闽西典型红壤区10个站年内降雨侵蚀力分布主要集中在3—8月,呈弱双峰式分布;R值年际间变化较大,1983年最大达525.31(MJ.mm)/(hm2.h),1991年最小为155.63(MJ.mm)/(hm2.h),最大值是最小值的3.38倍;年降雨侵蚀力在30a内未出现明显的突变现象;降雨侵蚀力空间分布不均匀,总体趋势为北部由东向西递增,南部由东南、西南向中间递减。

The soil erosion in typical red soil region of western Fujian is serious, especially in Changting, Nin- ghua county, etc. This area belongs to national key soil and water loss control region. The data from 10 sites of rainfall from 1980 to 2009 in Western Fujian was used to calculate the rainfall erosivity R and the temporal and spatial distribution characteristics of the regional rainfall erosivity was studied. It turned out that, rainfall erosivity distribution in 10 stations in typical red soil region of western Fujian mainly concentrated from March to August. It＇s a weak bimodal type distribution. The interannual change of R was large. The largest R was 525.31 （MJ·mm）/（hm^2·h） in 1983, the smallest R was 155.63 （MJ ·mm）/（hm^2·h） in 1991. The largest was 3.38 times of the smallest. Annual rainfall erosivity in 30 years did not appear obvious ab- rupt change. The spatial distribution of rainfall erosivity was uneven. The overall trend was the increase from the east to the west in the west part, and the decrease from the southeast and southwest to the intermediate in the south part.