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• 4.9.3 Replacement <br />Prior to topsoil replacement the spoil may be scared to reduce excessive compaction at the spoil/soil <br />interface if it is determined such conditions exist. <br />While topsoil is being replaced in an area, it is hand-checked with a shovel to confirm the-depth of <br />replacement. Due to the inability of scrapers to replace topsoil at exact amounts, an average depth of <br />±2 inches for final reclamation has been established on cropland and rangeland (actual cropland and <br />rangeland final depths are proposed at 180±2' and 120±2, respectively). In addition, no cropland area <br />of 1/2 acre or more shall have a topsoil depth <2' of the proposed minimum targeted topsoil amount. <br />For cropland salvage areas having less than 8' of suitable topsoil prior to disturbance, at least 8' of top- <br />soil will be replaced on those acres disturbed. On rangeland, topsoil replacement depth may vary as <br />approved by the Division. In the event topsoil replaced rangeland areas are significantly less than the <br />approved replacement range (12'±2'), special consideration may be allowed based on the site specific <br />finding of E.F. Redeme and T. McLandon (see 1991 report 'The influence of topsoil depth on plant com- <br />munity dynamics of a seeded site in northwest Colorado.•) <br />Soil samples are selectively taken to determine nutrient levels in the replaced topsoil. Fertilization prac- <br />tices are based on results obtained from analyses of these samples as well as plant response (see <br />Section 3.6.2.3 and 3.6.3.3 for more detail on fertilization practices). <br />• All retopsoiled areas are seeded the same year topsoil is replaced to achieve as rapid of vegetative sta- <br />bilization as is possible. On occasions, small areas of 30-40 acres may be retopsoiled but not seeded in <br />the same year as a result of early snow fall. Generally retopsoiled areas are directly seeded to <br />perennials. Compaction on retopsoiled areas is usually mitigated by the freeze-thaw action during <br />winter. Areas where over compaction results from repeated equipment travel or high soil moisture con- <br />tent are adequately treated to result in a proper seedbed. Erosion control measures such as contour <br />furrows, small depressions, land imprintings, etc. may be used to stabilize the topsoil and promote plant <br />establishment (see Sections 3.6.2.5 and 3.6.3.6). <br />On occasion it may be necessary to remove topsoil which has been replaced and seeded to perennials <br />in order to complete the regrading of adjacent spoils or to facilitate mining of additional coal reserves. <br />For example, where small areas of <br />u <br />4-256 <br />