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Prediction of Subsoil Erodibility Using Chemical, Mineralogical and Physical Parameters

Charles B. RothDarrell W. NelsonM. J. M. Römkens

出版	Superintendent of Documents,U.S.GovernmentPrint.Office, 1974
URL	http://books.google.com.hk/books?id=mRaE_laEmsQC&hl=&source=gbs_api
EBook	FULL_PUBLIC_DOMAIN

註釋This report presents evidence that the surface soil erodibility prediction nomograph (Wischmeier et al., 1971) which uses terms involving soil particle size, organic matter, structure and permeability, could not be improved upon by consideration of other mineralogical and chemical parameters. However, the surface soil erodibility nomograph did not adequately predict the soil erodibility factor, K, of high clay subsoils studied in the field under simulated rainfall conditions as a part of this project. A multiple linear regression equation and nomograph were developed which can be used to estimate the erodibility factor, K, of many high clay subsoils. The subsoil erodibility nomograph uses terms involving soil particle size distribution and the amount of amorphous hydrous oxides of iron, aluminum, and silicon in the soil. Multiple regression analysis revealed that amorphous iron, aluminum, and silicon hydrous oxides serve as soil stabilizers in subsoils, whereas organic matter is the major stabilizer in surface soils. Evidence is presented to show that soil erodibility from semi-compacted fill and scalped subsoil surface conditions were essentially identical. It is reported that the scalped condition is the best standard soil surface to base the calculation of the erodibility factor for subsoils. It is suggested that a soil-management factor should replace the cropping-management factor in the Universal Soil-Loss Equation when the Equation is used to predict subsoil erosion.