用田间实测法研究我国亚热带土壤的可蚀性K值

SOIL ERODIBILITY FACTOR K AS STUDIED USING FIELD PLOTS IN SUBTROPICAL CHINA

本文在自然降雨条件下用全裸地小区田间实测了我国亚热带七种有代表性的不同类型土壤的可蚀性K值，结果表明这七种不同类型土壤间的K值差别很大，其中紫色土和红砂岩发育的耕种普通红壤的K值最大，分别达到0．440和0．438，最小的是第四纪红色粘土发育的红色土，其值只有0．104，还不到紫色土K值的1／4。我们亦用国际上十分流行的诺谟图方法估算了这七种不同类型土壤的可蚀性K值，其中有二类土壤用这种方法所估算的K值较接近于田间实测的K值，有一类土壤相差较大，有三类土壤相差很大，还有一类土壤不能用这种方法来估算，因此，国际上十分流行的用诺谟图估算土壤可蚀性K值的方法对我国亚热带多数土壤并不合适。

In the work soil erodibility factor K of seven different types of soil in subtropical China was studied using field plots under natuUral rainfall condition. The field plotswere established in Yingtan of Jiangxi Province. The results showed that there were great differences among soil eredibility factor K of seven different types of soils.Among them calcaric regosols developed on purple shale and cultivated cambisol on red sandstone had the highest factor K, being up to 0.440 and 0.438 (0.132 k.hr/MJ.mm) respectively. The lowest was ereded acrisols derived from Quaternary red clay,with factor K of only 0.104, being less than 1/4 of the factor K value of purple soil.The soil erodibility factor K of seven types of soils were also estimated by using the Wischmeier's nomography. These results showed that the factor K vaules of two types of soils eshmated by the nomography were close to those measured using field plots,one of the seven types of soils had a bigger difference between the factor K obtained by the above two methods, three had a big difference, and one couldn't be estimated by the nomography. Therefore, the nomograph method for estimating soil erodibility factor K was almost unsuitable for the soil types in subtropical China.