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Order I Sail Survey, Now Horizon Mine
<br />657.5 Identification of important farmlands.
<br />(a) Prime farmlands.
<br />(1) General. Prime farmland is land that has the best combination of physical
<br />and chemical characteristics for producing food, feed, forage, fiber, and
<br />oilseed crops and that is also available for these uses (the land could be
<br />cropland, pastureland, rangeland, forest land, or other land but not urban or
<br />built -up land or water areas )_ It has the soil quality, growing season, and
<br />moisture supply needed to produoe sustained high yields of crops in an
<br />economic manner when treated and managed, including water, according to
<br />acceptable farming methods. In general, prime farmlands have an adequate
<br />and dependable water supply from precipitation or irrigation, a1 favorable
<br />temperature and growing season, acceptable levels of acidity or alkalinity, an
<br />acceptable content of salt and sodium, and few or ne rocks, They have soils
<br />that are permeable to water and air. Prime farmland is not excessively
<br />erodible or saturated with water for a long period of time, and it either goes
<br />not flood frequently or is protected from flooding. Examples of soils that
<br />qualify as prime farmland are Palouse silt loam, Q to 7 percent slopes;
<br />Brookston silty clay loam, drained; and Tama silty clay loam, 0 to 5 percent
<br />slopes.
<br />(2) Specific criteria. Terms used in this section are defined in USDA
<br />publications: "Sail Taxonomy, Agriculture Handbook 436," "Soil Survey
<br />Manual, Agriculture Handbook 18;" "Rainfall- Erosion Losses from Cropland,
<br />Agriculture Handbook 232;" "Wind Erasion Forces in the united States and
<br />Their Use in Predicting Soil Loss, Agriculture Handbook 340;" and "Saline
<br />and Alkali Soils, Agriculture Handbook 64." Prime farmlands meet all the
<br />fallowing criteria:
<br />(1) The soils have:
<br />(a) Aquic, udic, ustic, or xeric moisture regimes and a sufficient
<br />available water capacity within a depth of 40 inches (1 meter),
<br />or in the root zone (the root zone is the part of the soil that is
<br />penetrated or can be penetrated by plant roots) if the root zone
<br />is less than 40 inches deep, to produce the commonly grown
<br />cultivated crops (cultivated crops include, but are not limited to,
<br />grain, forage, fiber, oilseed, sugar beet, sugarcane, vegetable,
<br />tobacco, orchard, vineyard, and bush fruit crops) adapted to the
<br />region in 7 or more years out of 10; or
<br />(b) Xeric or ustic moisture regimes in which the available water
<br />capacity is limited, but the area has a developed irrigation water
<br />supply that is dependable (a dependable water supply is one in
<br />(430- VI -NSSH, 1996)
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