2002-03-04_REVISION - M1986015 (8)

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SOILS INFORMATION might contribute to similar problems here. Problematic soils do not necessarily need to be avoided in the salvage and replacement processes, but should be further examined to determine whether that particular soil should be eliminated from the growth medium and would best be used for other purposes. Because of the extreme difficulty of revegetating soils that are saline and/or sodic and especially so if they are clayey, not all topsoils present on this site should be considered of equal value and utility in the revegetation. The following units have been identified as being potentially problematic. Apishapa silty clay: The typical characteristics of this soil shows increasing ph and alkalinity with depth and the potential for salinity in excess of 4 to 6 mmhos/cm at 25°C. These are indicators of potentially saline and/or sodic soils that would require special treatment or unusual revegetation techniques. If surface indicators show possible problems, sampling of this soil should be done prior to salvage. The soils should be tested for salinity and SAR. If the salinity exceeds 6 and the SAR is higher than 12, the soil should not be salvaged and used in the revegetation program without special treatments including heavy leaching and potentially a separate seed mixture. Although these soils offer some potential for wetland creation, the high clay content would favor establishment of more or less monocultural populations of cattail which is often not quality wetland vegetation. Soils that exceed the maxima stated above would probably best be used in a buried backfill condition so they do not affect the surface vegetation. Haverson Portion of the Glenberg-Haverson £ne sandy loam: This soil exhibits problems similar to the Apishapa, but the potential for problems is considerably less. Maximum salinity is about 8 which is adequate for salt tolerant species, but the somewhat clayey texture could produce some problems. This soil should be identified and examined to insure it would not present severe problems if used for revegetation. Las Animas fine sandy loam: This soil can exhibit high salinity to 15 mmohs/cm. However, because it is a sandy loam the effects of the salinity will be less problematic and should leach rather readily. These soils should be approached with caution and should not be mixed with clay soils. The latter is especially true if the clay soil contains suitable growth properties as blending this soil will tend to degrade the clay soil making it hard and, if saline, expressing the salinity with greater intensity. Limon Series soils: Although usually good soils, these soils can have high salinity values. In general these soils can be safely assumed to be suitable, but the more clayey portions should be considered carefully as they might create some problems if salinity is above 6 mmohs/cm. Pueblo East Pit Amendment Exhibit i Page 3