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• were found to be statistically different in light of the fertility recommendations <br />for dryland grass, the proposed post mining land use, prepared by Colorado <br />State University (SoRanpour et. al. 1985) as well as the topsoil suitability <br />guidelines prepared by the Wyoming Department of Environmental Quality <br />(WDEQ) and the New Mexico Mining and Minerals Division (NMMMD). <br />~(. Apparent oxidization of materials in the waste coal has significantly <br />lowered the pH of the soils containing waste coal. These findings are <br />consistent with the results obtained by Kollman (1979) Safaya et. al. (1982) <br />who reported that the addition of slack coal to sodic mine spoils significantly <br />lowered the pH of these materials. In New Mexico, Gosz et. al. (1978) <br />reported that the addition of humate to uranium mine spoils lowered the pH. <br />Using the nutrient availability curves correlating pH to various nutrients (Fisher <br />and Munshower 1984) it can be observed that a drop in mean pH from 7.41 <br />to 8.32 will not adversely affect the system because P, biological activity, Cu, <br />Zn, Fe, and Mn availability are all higher at a pH of 8.32 as compared to a pH <br />of 7.41. Thus, some acidification of the natural soils can be viewed as being <br />desirable. Using the WDEQ pH suitability guidelines for topsoil, 88.5 percent <br />of the waste coal amended soils still possess a 'good' suitability as topsoil <br />material. The one sample having a pH value of 4.3, which ranks "unsuitable" <br />according to the WDEQ guideline is associated with a material that has a <br />much higher content of waste coal than the current coal levels associated <br />• with the Southfield Mine refuse pile. With the exception of this one atypical <br />sample, an argument can be made that the coal amended soils possess a <br />better suitability with respect to pH values and associated nutrient availability <br />levels than do the non coal amended soils. <br />~. The addition of coal waste to the topsoil signficantly increased the <br />electrical conductivity of the topsoil material. These findings are consistent. <br />with the resuRs reported by White et. al. (1982) for old waste coal in eastern <br />Utah and Western Colorado and by Kollman (1979) and Safaya et. al. (1982) <br />for mine spoils in North Dakota. Although EC was not measured in the New <br />Mexico humate studies (Gosz et. al. 1977 and 1978) they reported that <br />sodium was increased due to the application of oxidized carbonaceous <br />materials. However, since the EC values in the Southfield Mine coal <br />amended soils are all less than 3.07 mmhos/cm and would be considered to <br />be 'good' quality topsoil material according to both the WDEQ and NMMMD <br />guidelines this change is purely of an academic nature. With respect to EC <br />it appears that in the long term, addition of waste coal to topsoil does not <br />affect its suitability as a plant growth medium. <br />~. The waste coal soils had lower, aRhough not statistically significant, <br />SAR values than the non coal waste soils. Two of the components used to <br />calculate the SAR value, Ca and Mg, were both signficantly higher on the <br />• soils with waste coal, suggesting that the potential adversity of the Na was <br />being alleviated. In North Dakota, Kollman (1979) and Safaya et. al. (1982) <br />reported considerable reductions in SAR with the addition of slack coal to <br />highly sodic spoil. The similarity of SAR values between the coal and non <br />coal amended soils definitely document that the very high SAR values of the <br />24 <br />