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Table 4. Potential yield reduction from saline soils for selected crops. <br />Relative yield decrease <br />0 <br />10 <br />25 <br />50 <br />Field crops <br />(EC <br />Corn 1.7 <br />2.5 <br />3.8 <br />5.9 <br />Borch Environmental Pollution Consulting (BEPC) August 1, 2012 <br />D. Continuous or periodic waterlogging in the soil caused by slow permeability of <br />the underlying material, a high water table, or flooding. <br />E. Depth of soil material to layers inhibiting root penetration. <br />F. Salts toxic to plant growth. <br />G. Physical obstacles such as rocks, deep gullies, etc. <br />H. Climate (temperature and effective moisture). <br />This list is not intended to be a complete list of soil criteria. Although the soils of any area may <br />differ from one another in only a few dozen characteristics, none can be taken for granted. <br />Extreme deficiencies or excesses of trace elements, for example, can be vital. Commonly, the <br />underlying geological strata are significant to water infiltration, water yield, and erosion hazard. <br />2. The reclaimed soil needs to meet the criterion for "Prime- farmland soil" as defined by <br />NRCS and regulations promulgated by the Colorado Division of Reclamation Mining & <br />Safety (DRMS). <br />3. The chemical composition of the soil that is going to replace the original soil needs to <br />match within reasonable limits especially with respect to the electrically conductivity <br />(EC), and pH since these factors have an important impact on Alfalfa crop yield. For <br />instance, excessive soil salinity reduces the yield of many crops. This ranges from a slight <br />crop loss to complete crop failure, depending on the type of crop and the severity of the <br />salinity problem. Table 4 shows the relative salt tolerance for corn and alfalfa (modified <br />from CSU Extension Managing Saline Soils Fact sheet No. 0.503). The table shows the <br />approximate soil salt content (expressed as the electrical conductivity of a saturated paste <br />extract (ECe) in dS /m at 25 degrees C) where 0, 10, 25, and 50 percent yield decreases may <br />be expected. Actual yield reductions will vary depending upon the crop variety and the <br />climatic conditions during the growing season. Alfalfa suffers a 10 percent yield reduction <br />when soil salinity levels reach approximately 3.4 dS /m. In general, soils with ECe values <br />above 5.0 should be avoided or reclaimed prior to planting (alfalfa intermountain alfalfa <br />management, UC California, publication 3366). <br />Page 6 of 13 <br />