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1 field there are many variables such as uneven surface water application <br />2 and fingering within the water flow in the field below the root zone <br />3 that will add to the unpredictability of the salt concentration curve. <br />4 Fingering is the uneven distribution.of flow within the spoil material <br />5 caused by a slower saturated hydraulic conductivity at the surface than <br />6 that below. <br />~ The total leachable salts would be best determined from the area <br />$ under a curve of salt concentration versus water leached. This <br />9 requires that the material be leachable which is not always the case. <br />LO Therefore a batch determination is more practical. The standard test <br />• <br />L1 to determine salts in soils is the sagt/uration extract as reported in <br />L2 the USDA Agriculture Nandbook No. 60~ . This teat vas originally <br />L3 Planned to determine salt concentrations in the soil as related to <br />plant growth. The estimation of salts available for leaching from <br />disturbed material requires that all salts readily available for <br />leaching be accounted for. The saturation extract is not adequate for <br />L~~thia purpose. It is based on the subjective determination of <br />Lg~eaturation which cannot accurately be predetermined and often is not <br />L9~repozted. In addition the amount of salt contained in spoil material <br />that can be readily dissolved is usually greater than that which will <br />tl~disaolve in the amount of water used for the saturation extract. <br />To determine total dissolved solids it is necessary to use a <br />t3~4uantity of water for the determination large enough to dissolve all <br />the readily soluble salts. It is recognized that the presence of <br />gypsum will have to be accounted for but that also is the case for the <br />saturation extract. <br />rq~ Rowe and NcWhorter5~ related the 1:1 extract back to the <br />9 <br />