1988-04-29_PERMIT FILE - C1981008A (53)

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for information concerning prime farmland within the PCC Nucla East study area. In 1982, they issued a revised publication entitled "Important Farmland Inventory - Colorado" (SCS, October 1982). This document, as well as a supplementary publication entitled "Important Farmlands of Colorado - State Summary and Map" (SCS and Colorado State University Agricultural Experiment Station, 1980) were reviewed. The Montrose County SCS District Office in Norwood, Colorado, was also contacted for determination of prime farmland status for the study area. Individual land owners were contacted concerning the availability of late growing season irrigation water. The PCC Order 1 soil survey accurately determined the soils present on the study area. This soil survey was compared with the SCS survey concerning potential prime farmland soil mapping units. Evaluation of Soils for Reclamation Potential . The soils and parent materials on the PCC Nucla East study area were rated for suitability based on criteria presented in Table 9-5-2, Criteria for Evaluating Soil Suitability. These suitability criteria were approved by CMLRD in the scope-of-work. Recommended topsoil salvage depths were generated for each sampled pedon and each component of a mapping unit. Salvage depths were determined following a detailed evaluation of pH, electrical conductivity, saturation percent, soil texture, Sodium Adsorption Ratio, calcium carbonate percent, and coarse fragment percent. Topsoil salvage depths were based on average depths to the suspect parameter or average profile depths (if the entire profile was suitable) across the study area based on numerous soil profile descriptions obtained for each soil type. A two lift soil handling operation is proposed for irrigated hayland and the cropland soils. Field parameters including structure, consistence, effervescence, organic matter content, and rooting characteristics were used, in addition to the criteria listed in Table 9-5-2, to differentiate the first and second lift soil material . Two recommended topsoil salvage depths were generated for irrigated hayland and cropland. The first includes only the best topsoil material , generally noncalcareous soil including the A horizon, the AC horizon (if present), the Bw horizon (if present), and the upper Bt horizon (if present). When the AC or Bw horizon is thin, the uppermost C horizon is often included. The Btk and Bk horizons, zones of clay and/or carbonate accumulation often accompanied by massive structure and hard consistence, are not included in this 9-5-16 Revised 04/11/88