2002-07-08_GENERAL DOCUMENTS - M2002004 (3)

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206 SMITH, REDENTE, and HOOPER piing program should insure collection of soil from one typifying pedon (all genetic horizons) of each soil series mapped. If several map units of the same soil series exist within the permit area, because the organic matter con- tent of each map unit varies by more than 33 percent, one typifying pedon of each map unit should be sampled. The detail of the soil survey depends upon whether topsoil or overbur- den/interburden will be used as the plant growth medium during reclama- tion. Where topsoil salvage and replacement is proposed, an order -1 soil survey should be used to characterize baseline organic matter and other soil properties. Where use of overburden /interburden is proposed, an order -2 soil survey provides sufficient baseline characterization to perform topsoil substitution evaluations. The primary intent of an order -1 soil survey is to identify topsoil stripping depths for each map unit, along with obvious topsoil stripping depth cri- teria, such as texture or salinity. Thus, organic matter content should be in- cluded as a basis for setting up additional phases (map units) of any soil series. Once in the field, if the soil scientist suspects that the proportionate amount of organic matter might vary more than 33 percent within any soil series (e.g., 2.5 percent organic matter versus 4.0 percent), different phases of the soil series should be established and mapped, provided the different phases are distinguishable on aerial photographs and topographic or native vegetation differences are observed in the field. For example, if in a culti- vated field the soil scientist could delineate on aerial photography an eroded condition of the same soil series occurring in an adjacent, less eroded, rangeland setting, different phases of the same soil series should be mapped to distinguish the soil with a lower organic matter content from the soil with a higher organic matter content, assuming a minimum map unit size crite- rion is fulfilled. Similarly, the thickness of the A horizon should be included as a basis for additional map unit phases, assuming no other limiting soil conditions oc- cur in the A horizon. If the thickness of the A horizon within a particular series varies by more than 15 cm because of an identifiable management, topographic, or native vegetation difference, different phases of the soil series should be set up in the map unit legend. For example, a slightly more concave position with a thicker A horizon due to a greater amount of deposition should be identified as a "thick -A" phase. It should be delineated separately on aerial photography from adjacent, less concave areas because the phase difference is distinguishable based on topography and fulfillment of minimum size delineation criteria. Summary and recommendations Reestablishment of a functional soil system is critical to the successful reclamation of surface mined areas in the arid and semiarid West (21). An SOIL ORGANIC MATTER important, integral part of this f organic matter formation. Hence soil organic matter formation rn with the optimum organic matter ganic matter formation is vegetat regular basis. Vegetation and microbial populations to predistt activity starts the active cycling c end products of decomposition microorganisms. As the cycles cc tility will increase and eventually What is the optimum level of land? Research has not yet ident we believe it will even vary within level should be the stable, baseli from mine to mine and within ea level is a function of several vary tics; microclimate; site - specific v. management, topography, and l: may be less important than some ing those replaced on reclaimed 1; is matter and will have a minim: Several characteristics of soil are useful as they Telate to indi growth media. Soil organic math fied on the basis of total organic than total organic matter. In add quantify vesicular - arbuscular rr provide planning target levels. Ti modified Mebius technique (58). ter content using the loss -on -igni perature (430 °C) has promise as content, the method is not recc evaluation of its usefulness and The sampling program should pedon —all genetic horizons —o units of the same soil series exist having an A horizon thickness o than 33 percent, at a minimum o be sampled. Many species of plants that a; may be dependent on vesicular -a ulum levels in disturbed soil ma choosing against such plants, r