建立小流域风蚀量统计模型初探

Establishing Statistic Model of Wind Erosion on Small Watershed Basis

根据模拟实验及野外实测资料，以陕北神木县六道沟为例建立了小流域土壤风蚀流失量的经验估算模型，并以此模型估算该小流域的年风蚀量、风蚀模数。计算结果表明：六道沟小流域的风蚀模数为１８８７．２７ｔ／（ｋｍ２·ａ），相当于１．２５ｍｍ／ａ，接近强度风蚀。春季是主要风蚀季节，占年风蚀总量的９９．９８％以上，其中又主要集中于４—５月，占年风蚀量的９９．３０％。若该小流域的平均侵蚀模数按２５０００ｔ／（ｋｍ２·ａ）计，则风蚀占总土壤侵蚀的７．５５％，风蚀量与水蚀量之比为１∶１２．２５。在该小流域，风蚀与水蚀在时间序列上交错分布，前后相连。

Taking Liudaogou small watershed as an example, based on simulative experiment from laboratory and field observation, attempts to establish wind erosion loss prediction model which are furthur used to estimate the amount of wind erosion loss and wind erosion modulus. It is found through the model estimation that the wind erosion modulus in Liudaogou small watershed is 1 887.27 t/(km 2·a), corresponding to 1.25 mm/a, close to the severe erosion type. If the meam erosion modulus of this area is 25 000 t/a, the percentage of wind erosion out of total erosion is 7.55%, and the ratio of wind erosion to water erosion is 1∶12.25. Of the total erosion ,99.98% is concentrated in spring and 99.30% is concentrated in April and May. The wind erosion season is followed by water erosion season, constituting severe erosion.