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<br />45 <br />~ The mean estimated "soil" loss of the spoils was calculated for <br />• each site, using the complete equation in Table 7 and only the basic <br /> equation (A = R x K) in Table 8. For ease of comparison between the <br /> topsoil and spoils, and since nontopsoiled spoils generally were not <br /> <br /> available for measurement of vegetation, the ground cover factor, C, <br />-. was assumed to be the same for the spoils as for the topsoil. Obviously <br /> the spoils would be a different plant growing medium than the topsoil <br /> and sharp differences in ground cover could occur (Yamamoto, 1975; <br /> Poyser et al., 1976). The mean "soil" (spoils) loss estimates (Table 7) <br /> using the complete equation are very similar to the mean soil (topsoil) <br /> loss estimates (Table 5) using the complete equation, both in range of <br />- values and ranking of sites. In addition, the mean "soil" (spoil's) loss <br />' estimates (Table 8) using the basic equation are very similar to the mean <br /> soil (topsoil) lass estimates (Table 6} using the basic equation. Since <br />• all the factors except soil erodibility were held constant in calculating <br />_ estimated soil lasses of the topsoil and spoils in Tables 5, 6, 7, and <br /> 8, the only source of variation between the estimates of soil loss from <br />- topsoil and spoils is the K factor. Table 9 compares the mean K factor <br /> for the topsoil and spoils for each site. The average paired difference <br /> between the K factors of the topsoil and spoils is only about 0.13 (metric <br /> units). <br /> The mean K factors of topsoil for the sampling sites are ranked in <br />- Table 9 from highest to lowest. K factors for the coal regions are <br /> grouped together, indicating a distinct trend in topsoil erodibilities <br /> between regions, with highest erodibilities in the Green River and lowest <br />erodibilities in the North Park and Uinta Coal Regions. However, differ- <br />ences between K factors are small and, although a definite trend exists, <br />may not be significant. <br />