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soil Information for II Uses <br />suitabilities and Limitations for Use <br />The suitabilities and Limitations for Use section includes various soil interpretations <br />displayed as thematic maps with a summary table for the soil map units in the selected <br />area of interest. A single value or rating for each map unit is generated by aggregating <br />the interpretive ratings of individual map unit components. This aggregation process <br />is defined for each interpretation. <br />Land Classifications <br />Land Classifications are specified land use and management groupings that are <br />.;--. assigned to soil areas because combinations of soil have similar behaviorfor specified <br />practices. Most are based on soil properties and other factors that directly influence <br />the specific use of the soil. Example classifications include ecological site <br />classification, farmland classification, irrigated and nonirrigated land capability <br />classification, and hydric rating. <br />Hydric Rating by Map Unit <br />This rating indicates the proportion of map units that meets the criteria for hydric soils. <br />Map units are composed of one or more map unit components or soil types, each of <br />which is rated as hydric soil or not hydric. Map units that are made up dominantly of <br />hydric soils may have small areas of minor nonhydric components in the higher <br />positions on the landform, and map units that are made up dominantly of nonhydric <br />soils may have small areas of minor hydric components in the lower positions on the <br />landform. Each map unit is designated as "all hydric," "partially hydric," "not hydric," <br />or "unknown hydric," depending on the rating of its respective components. <br />"All hydric" means that. all. components listed for a given map unit are rated as being <br />hydric, while "not hydric" means that all components are rated as not hydric. "Partially <br />hydric" means that at least one component of the map unit is rated as hyric, and at <br />least one component is rated as not hydric. "Unknown hydric" indicates that at least <br />one component is not rated so a definitive rating for the map unit cannot be made. <br />Hydric soils are defined by the National Technical Committee for Hydric Soils <br />(NTCHS) as soils that formed under conditions of saturation, flooding, or ponding long <br />enough during the growing season to develop anaerobic conditions in the upper part <br />17 <br />