SOIL SURVEY

-163-of Tables 58 through 64 . When conditions of use and management ar enot the same as those defined here, new guides should be establishe dand appropriate revisions made in Table 67 .2. Soil ratings do not include site factors such as nearness to towns an dhighways, water supply , aesthetic values, etc .3. Soil ratings are based on natural, undisturbed soil .4. Soil suitability or limitation ratings are usually given for the entire soils ,but for some uses, soil limitations are based on an individual soil horizo nor other earthy layer, because of its overriding importance . Rating srarely apply to soil depths greater than 1 to 2 meters, but in some kind sof soils, reasonable estimates can be given for soil material at greate rdepths . It should be noted here that the term "soil" has been use dthroughout the report in the pedologic sense and differs in concept fro mthat commonly used by engineers .5. Severe and very severe soil ratings do not imply that a site cannot b echanged to remove, correct or modify the soil limitations . The use ofsoils rated as severe depends on the nature of the limitations, whether o rnot the soil limitation can be altered successfully and economically, an don the scarcity of good sites .6. Interpretations of map units do not eliminate the need for on-site evaluationby qualified professionals . Due to the variable nature of soils, andthe scale of mapping, small, unmappable inclusions of soils with differen tproperties may be present in an area where a development is planned .The need for or importance of on-site studies depends on the use to b emade of the soil and the kinds of soil and soil problems involved .