我国南方地区降雨侵蚀力特征及简易算法研究——以江西省鹰潭地区为例

Characteristics of Rainfall Erosivity and Simple Algorithm in South China——Taken Yingtan Area of Jiangxi Province as a Case

以我国南方亚热带地区的江西省鹰潭市红壤生态试验站自建气象站1997—2003年度观测资料和该站不同类型径流小区的实测数据为例,研究了我国南方地区自然降雨侵蚀力(R)特征及其初步的简易算法。结果表明,研究区1997—2003年每年降雨过程和降雨侵蚀力的产生主要发生在3—8月。根据R值的"EI30"方法计算出1997—2003年的降雨侵蚀力分别为:7 231.8,12 051.9,3 722.3,6 864.2,4 520.5,6 299.1和5 580.9MJ.mm/(hm2.h.a);降雨侵蚀力呈现出年际变化大,且月分布极不均衡的特点。通过分析7a中244次侵蚀性降雨的雨量与侵蚀力的关系以及土壤流失量资料,初步建立了研究区降雨侵蚀力的简易算法。通过检验表明新简易算法在研究区面积分布较广的紫色湿润雏形土上要优于"EI30"经典算法,在黏淀湿润富铁土和铝质湿润淋溶土上与"EI30"经典算法预测精度相差不大,说明该算法可以作为一个通式在研究区推广。

Rainfall erosivity and its characteristics were studied by analyzing rainfalls and soil erosion data recorded within the period of 1997—2003 at the ecological experiment station of red soil（EESRS）,which is located in Yingtan area,Jiangxi Province.The results indicate that for the studying area,the events of rainfalls and erosive rainfalls occurred from March to August in each year.According to the method of R ＂EI30＂ value,the rainfall erosivity was 7 231.8,12 051.9,3 722.3,6 864.2,4 520.5,6 299.1 and 5 580.9 MJ·mm/（hm2·h·a） for the years from 1997 to 2003,respectively.The rainfall erosivity varied considerably not only in years,but also in months.Finally,the simple and easy algorithm for rainfall erosivity calculation was proposed based on the analysis of the relationship between the rainfall volume and sediment yield during the 244 events of erosive rainfall within the seven years.Based on the validation,the simple algorithm performed better than the traditional algorithm of EI30,particularly for the widespread purpli-udic cambosols.However,the accuracy of the simple algorithm remained almost the same as the traditional algorithm in the soils of ali-udic argosols and typic argi-udic ferrosols.The results indicate that the new simple algorithm might be suitable for wide use in the study area.