2010-09-22_REVISION - C1981008 (7)

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6. The soils are not flooded freguently during the growing season (less often than once in 2 years); and, 7. The product of K (erodibility factor) x percent slope is less than 2.0, and the product of I (soils crodibility) x C (climatic factor) does not exceed 60; and, 8. The soils have a permeability rate of at least 0.06 inch (0.15 cm) per hour in the upper 20 inches (50 cm) and the mean annual soil temperature at a depth of 20 inches (50 cm) is less than 59 (15 the permeability p ate ig not a limiting factor if the mean annual soil temperature is 59 O F (15'C) or higher; and, 9. Less than 10 percent of the surface layer (upper 6 inches) in these soils consists of rock fragments coarser than 3 inches (7.6 cm). The following modifications and /or interpretations of the National Criteria for Prime Farmlands were used in Colorado. The soil must have: 1. A developed irrigation water supply that is dependable and adequate to meet moisture requirements 8 out of 10 years and have 4 inches or more available water capacity within a depth of 40 inches (1 meter), or within the root zone if the root zone is less than 40 inches; 2. A growing season of 90 days or more; 3. No water table or the water table is below a depth of 1.5 feet and drainage is possible; s� 4. A conductivity of 8 mmhos /cm or less in the upper 40 inches and permeability is greater than .2 inches /hr. (moderately slow or greater) if the slope is less than 2 percent. These soils are considered capable of being managed so that all horizons within a depth of 40 inches (I meter) or in the root zone if it is less than 40 inches will have a conductivity of the saturated extract of less than 4 mmhos /cm and the exchangeable sodium percentage (ESP) is less than 15; irrigated soils with bedrock within 40 inches of the surface and soil horizons that have a pH higher than 7.4 are considered as having high conductivity and therefore not prime; S. slope of irrigated prime farmland will not exceed 6 percent. Unique Farmland Unique Farmland is land other than Prime Farmland that is used for the production of specific high value food and fiber crops. It has the special combination of soil quality, location, growing season, and moisture supply needed to economically produce sustained high quality and /or high yield of a specific crop, when treated and managed according to acceptable farming methods. Two areas in Colorado are considered Unique Farmlands of National Importance -- the fruit orchards in the Grand Valley and the Delta - Montrose areas, and the seed potato and fruit and - vegetable producing areas of the San Luis Valley. 3 Attachment 2.04.9 -5 -8