Aboufayed Equations for Evaluation Erodibility Factor (K) of Some Libyan Soil

Abstract

To establish an equation for prediction of the Libyan soil erodibility factor (K), samples of the main three types of Libyan soil were collected. The soil erodibility factor was evaluated in an indirect way by measuring the soil erosion rate and using the universal soil loss equation (K=A/RLSCP). The soil properties related to soil erodibility were also measured to establish the equation for prediction of the Libyan soil erodibility factor based on its soil properties. The simple linear regression was used to determine the first soil property in the model, which has the highest correlation coefficient (R) between the soil erodibility factor as a dependent variable and soil properties as independent variables. Multiple linear regression analyses were used to determine the soil properties variables that have a significant effect on the prediction of the equation (1) with a high determination coefficient (R²=83.5%), as shown in the following equation:

(K=-1.0+0.02(vfs) +0.06(fs)+0.1(Pd))…………..................................………............. (1)

Where (vfs) is the percent of soil content of very fine sand, (fs) is the percent of soil content of fine sand, and (Pd) is the soil permeability degree. And another equation was reached that depended on very fine sand and the square of very fine sand with a very high determination coefficient (R=83.7%), as shown by equation (2):

K=-0.07-0.005(vfs%)+0.00025(vfs%)²…………............……….(2)          

The equations is known as Aboufayed equations regarding to the researcher's hard work to reach these equations.