Laserfiche WebLink
Attribute Name: Range Production (Normal Year) <br />Total range production is the amount of vegetation that can be expected to grow annually in a well managed area that is supporting <br />the potential natural plant community. It includes all vegetation, whether or not it is palatable to grazing animals. It includes the <br />current year's growth of leaves, twigs, and fruits of woody plants. It does not include the increase in stem diameter of trees and <br />shrubs. It is expressed in pounds per acre of air -dry vegetation. In a normal year, growing conditions are about average. Yields are <br />adjusted to a common percent of air -dry moisture content. <br />In areas that have similar climate and topography, differences in the kind and amount of vegetation produced an rangeland are <br />closely related to the kind of soil. Effective management is based on the relationship between the soils and vegetation and water. <br />Units of Measure: pounds per acre per year <br />Aggregation Method: Weighted Average <br />Range Production (Normal Year) <br />Rating Options <br />Aggregation is the process by which a set of component attribute values is reduced to a single value to represent the map unit as a <br />whole. <br />A map unit is typically composed of one or more "components ". A component is either some type of soil or some nonsoil entity, <br />e.g., rock outcrop. The components in the map unit name represent the major soils within a map unit delineation. Minor <br />components make up the balance of the map unit. Great differences in soil properties can occur between map unit components <br />and within short distances. Minor components may be very different from the major components. Such differences could <br />significantly affect use and management of the map unit. Minor components may or may not be documented in the database. The <br />results of aggregation do not reflect the presence or absence of limitations of the components which are not listed in the database. <br />An on -site investigation is required to identify the location of individual map unit components. <br />For each of a map unit's components, a corresponding percent composition is recorded. A percent composition of 60 indicates that <br />the corresponding component typically makes up approximately 60% of the map unit. Percent composition is a critical factor in <br />some, but not all, aggregation methods. <br />For the attribute being aggregated, the first step of the aggregation process is to derive one attribute value for each of a map unit's <br />components. From this set of component attributes, the next step of the aggregation process derives a single value that represents <br />the map unit as a whole. Once a single value for each map unit is derived, a thematic map for soil map units can be generated. <br />Aggregation must be done because, on any soil map, map units are delineated but components are not.The aggregation method <br />"Weighted Average" computes a weighted average value for all components in the map unit. Percent composition is the weighting <br />factor. <br />The result returned by this aggregation method represents a weighted average value of the corresponding attribute throughout the <br />map unit. <br />Tie -break Rule: Higher <br />The tie -break rule indicates which value should be selected from a set of multiple candidate values, or which value should be <br />selected in the event of a percent composition tie. <br />Interpret Nulls as Zero: Yes <br />This option indicates that a null value for a component should be converted to zero before aggregation occurs. This will be done <br />only if a map unit has at least one component where this value is not null. <br />USDA Natural Resources <br />mill Conservation Service <br />Application Version: 5.2.0016 05/22/2012 <br />33 <br />Page 2 of 2 <br />