摘要
生产建设项目是水土流失防治和监管的重要对象,其中农林开发等项目的扰动主要表现为植被覆盖减少,土壤物理性质改变,但仍维持原有地形特征,因此多采用USLE或CSLE等土壤流失方程计算侵蚀量。然而,一般扰动地表土壤物理性质改变而引起的侵蚀量变化无法在上述方程中得到充分反映。本研究引入土壤可蚀性因子增大系数表征一般扰动地表土壤趋于疏松引起的土壤侵蚀量变化,并通过筛选修筑时土壤遭受类似农林开发等一般扰动的裸露小区实测资料,将小区修筑初期土壤物理性质变化和小区修筑后土壤沉降后2个时期实测侵蚀量进行对比,得到土壤可侵蚀性因子增大系数;然后基于Wischmeier土壤可蚀性因子算式,提出了一种主要通过改变结构等级和渗透等级取值的增大系数简易算法。研究认为:基于小区实测的东北黑土区、北方土石山区、西北黄土高原区、西南紫色土区和南方红壤区的增大系数分别为1.68、2.69、1.90、2.65和2.03,全国可取均值2.11;基于各地径流小区实测增大系数,建立了基于Wischmeier公式的简易算法。研究成果能提高基于土壤流失方程的一般扰动地表土壤侵蚀量测算精度,为生产建设项目水土流失防治和监管提供支撑。
[Background]The productive and construction projects are usually considered as the important objects for soil erosion prevention and supervision.As one type of the productive and construction projects,the agricultural and forestry construction projects usually disturb surface soil,reduce the vegetation cover and alter the soil physical properties;however,the overall landform has not been greatly changed for these projects and soil erosion for this kind of disturbed land,the general disturbed land,was usually estimated via empirical models,such as USLE or CSLE.However,the effect of changes in soil physical properties on soil erosion has not been taken into in these methods since the soil erodibility factor was usually assumed the same before and after the disturbance,which may reduce the accuracy of USLE and CSLE.[Methods]A new parameter named as"the enhancement coefficient of soil erodibility factor"was introduced to these models to reflect such effects.It is found that the disturbance during the construction of runoff plots was similar as the genal disturbance land,thus lots of runoff plot data was collected to reflect the effects of general disturbance on soil erosion.For each plot,two periods were quantified:the period that the construction of runoff plot has been just finished and the soil physical properties have already been changed and the period that the natural settlement of disturbed soil has been finished.Based on the runoff plot data,it is found that the first period usually last for about2-3 years.Soil erosion rates of the two periods from runoff plots were compared under the same conditions,and then the ratio of soil erosion rates between the two periods,which was also the enhanced coefficient of soil erodibility factor,was estimated.Then a simple formula based on the Wischmeier formula was established to estimate this coefficient by altering the soil texture grades and the infiltration grades in the Wischmeier formula.[Results]Runoff plots at 18 sites were selected for estimating the enhancement coefficients.The results indicated that the estimated coefficients based on runoff plot data for the Northeast Black Soil Region,North Earthy and Rocky Mountain Region,Northwest Loess Plateau Region,Southwest Purple Soil Region,Southern Red Soil Region were 1.68,2.69,1.90,2.65 and2.03,respectively,with the mean value of 2.11.A simple formula for estimating the coefficients was also established based on the Wischmeier formula and the coefficients estimated from runoff plot data.[Conclusions]This study provides a simple method for estimating the enhancement coefficients of soil erodibility factor for the general disturbed soil based on the runoff plot data and the Wischmeier formula,which may improve the estimation accuracy of soil erosion modulus on the general disturbed soil surface based on the soil loss equation.The results of this study are valuable for soil erosion prevention and supervision for the production and construction projects.
作者
郭乾坤
秦伟
宁堆虎
单志杰
殷哲
杜鹏飞
GUO Qiankun;QIN Wei;NING Duihu;SHAN Zhijie;YIN Zhe;DU Pengfei(China Institute of Water Resources and Hydropower Research,100048,Beijing,China;Research Center on Soil and Water Conservation of the Ministry of Water Resources,100048,Beijing,China;International Research and Training Center on Erosion and Sedimentation,100048,Beijing,China)
出处
《中国水土保持科学》
CSCD
北大核心
2019年第6期85-92,共8页
Science of Soil and Water Conservation
基金
水利部公益性行业科研专项经费项目“生产建设项目水土流失测算共性技术研究”(201001036)
水利部公益性行业科研专项经费项目“水土保持生态效应监测与评价技术研究”(201501045)
关键词
生产建设项目
一般扰动地表
土壤侵蚀
土壤可蚀性因子
土壤流失方程
production and construction project
generally disturbed land
soil erosion
soil erodibility factor
soil loss equation
