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Custom Soil Resource Report <br /> Map Unit Descriptions (Two Rivers Ranch <br /> Area Soils) <br /> The map units delineated on the detailed soil maps in a soil survey represent the <br /> soils or miscellaneous areas in the survey area. The map unit descriptions, along <br /> with the maps, can be used to determine the composition and properties of a unit. <br /> A map unit delineation on a soil map represents an area dominated by one or more <br /> major kinds of soil or miscellaneous areas. A map unit is identified and named <br /> according to the taxonomic classification of the dominant soils. Within a taxonomic <br /> class there are precisely defined limits for the properties of the soils. On the <br /> landscape, however, the soils are natural phenomena, and they have the <br /> characteristic variability of all natural phenomena. Thus, the range of some <br /> observed properties may extend beyond the limits defined for a taxonomic class. <br /> Areas of soils of a single taxonomic class rarely, if ever, can be mapped without <br /> including areas of other taxonomic classes. Consequently, every map unit is made <br /> up of the soils or miscellaneous areas for which it is named and some minor <br /> components that belong to taxonomic classes other than those of the major soils. <br /> Most minor soils have properties similar to those of the dominant soil or soils in the <br /> map unit, and thus they do not affect use and management. These are called <br /> noncontrasting, or similar, components. They may or may not be mentioned in a <br /> particular map unit description. Other minor components, however, have properties <br /> and behavioral characteristics divergent enough to affect use or to require different <br /> management. These are called contrasting, or dissimilar, components. They <br /> generally are in small areas and could not be mapped separately because of the <br /> scale used. Some small areas of strongly contrasting soils or miscellaneous areas <br /> are identified by a special symbol on the maps. If included in the database for a <br /> given area, the contrasting minor components are identified in the map unit <br /> descriptions along with some characteristics of each. A few areas of minor <br /> components may not have been observed, and consequently they are not <br /> mentioned in the descriptions, especially where the pattern was so complex that it <br /> was impractical to make enough observations to identify all the soils and <br /> miscellaneous areas on the landscape. <br /> The presence of minor components in a map unit in no way diminishes the <br /> usefulness or accuracy of the data. The objective of mapping is not to delineate <br /> pure taxonomic classes but rather to separate the landscape into Iandforms or <br /> Iandform segments that have similar use and management requirements. The <br /> delineation of such segments on the map provides sufficient information for the <br /> development of resource plans. If intensive use of small areas is planned, however, <br /> onsite investigation is needed to define and locate the soils and miscellaneous <br /> areas. <br /> An identifying symbol precedes the map unit name in the map unit descriptions. <br /> Each description includes general facts about the unit and gives important soil <br /> properties and qualities. <br /> Soils that have profiles that are almost alike make up a soil series. Except for <br /> differences in texture of the surface layer, all the soils of a series have major <br /> horizons that are similar in composition, thickness, and arrangement. <br /> Soils of one series can differ in texture of the surface layer, slope, stoniness, <br /> salinity, degree of erosion, and other characteristics that affect their use. On the <br /> 12 <br />