Agenda - 08-10-1994 - Laserfiche WebLink

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indicate progressively greater limitations and narrower choices for practical use. The classes are defined as follows: 1. Class I soils have few limitations that restrict their use. (None in Orange County) 2. Class II soils have moderate limitations that reduce the choice of crops or require moderate conservation practices. 3. Class III soils have severe limitations that reduce the choice of crops or require special conservation practices, or both. 4. Class IV soils have severe limitations that reduce the choice of crops or require very careful management, or both. 5. Class V soils are not likely to erode but have other limitations, impractical to remove, that limit their use. (None in Orange County) 6. Class VI soils have severe limitations that make them generally unsuitable for cultivation. 7. Class VII soils have very severe limitations that make them unsuitable for cultivation. 8. Class VIII soils have limitations that nearly preclude their use for commercial crop production. (None in Orange County) Capability subclasses are soil groups within one class. They are designated by adding a letter E, W, or S to the class numeral, for example, IIE. The letter E means that the main limitation is risk of erosion unless close-growing plant cover is maintained.Wmeans that water in or on the soil interferes with plant growth or cultivation. S means that the soil is limited mainly because of inherent soil qualities. Soils are placed in agricultural groups according to their land capability class. The lowest land capability class for the soils should occur in agricultural group 1,with subclass designations used to identify different groups; e.g., IIE in group 2, IIW in group 3, etc. It is acceptable, however, to have agricultural groups that have more than one capability class or subclass. The land capability classes and subclasses for Orange County soils are shown in Appendix A and Column 4 of Table 2.2.2. Soil Productivity Index: Soil productivity is the capacity of a soil to produce a specified crop using the most recent soil and crop management practices,and is reflected in the estimated yield/acre that can be expected. Estimated yields are based on the records of farmers, conservationists, and extension agents. It is the differences in yields of a specific crop on different soils that provide a measure of comparison among soils. To derive the productivity index for a given soil or group of soils, an indicator crop, such as corn, is selected which represents the single most cultivated crop.Next,the estimated yields for corn on various soils are obtained from the local soil survey or the local or state Soil Conservation Service office. If the estimated yield exceeds 100 bushels/acre for any soil, it is converted to 100, and all other yields are converted to an index relative to 100. For example, the estimated yield for a corn crop on Hiwassee soil is 103 bushels/acre. Thus,the productivity index would be 100 (103/103 = 1 x 100).For Altavista soil,the estimated yield is 100 bushels/acre, and the productivity index would be 97 (100/103 = .97 x 100). 2.2.2