1999-04-21_PERMIT FILE - M1999024

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U.S. DEPARTMENT UP AGRICULTURE PAGE 3 OF G NATURAL~RESGURCES CGNsERVATION SERVICE • ~ Od/il/va PHYSICAL PROPERTIES OF SOILS Endnote -- PHYSICAL PROPERTIES OF SUILs--Continued ORGANIC MATTER is the plant end animal residue in the soil et various stages of decomposition. In report J, the estimated content of organic matter is expressed as a percentage, by weight, of the soil material that is less than i millimeters in diameter, the content of organic matter in a soil can be maintained or increased by returning crop residue to the soil. Organic matter affects the available eater capacity, infiltration rate, and filth. It is a source of nitrogen and other nutrients for crops. EROSION FACTOk k indicates the susceptibility of the whole soli Iincludin9 rocks and rock fragments) to sheet and rill erosion by eater. Factor K is one of six factors used in the Universal So ii Loss Eouation (LISLE) to predict the average annual rate of soil loss by sheet and rill erosion in tons per acre oar year. The estimates are based primarily on percentage pf silt, sand, end organic matter (up to G percent) end on soil structure and permeability. Values of K range from O.US to U.ov. The higher the value, the more susceptible the sail is to sheet end riL1 erosion by voter. ERUSIUN FACTOR Kf is like ERUSIUN FACTOR K but it is for the fine-earth fraction of the soil. Rocks and rock fragments are not considered. ERUSIUN PACTOk T is an estimate of the maximum average annual rate of soil erosion by wind or eater that can occur without effecting crop productivity over a sustained peripd. the rate is in tons per acre per year. NINU EROUIBILIi'Y GROUPS are made up of soils that have similar Droperties affecting their resistance to wind erosion in cultivated areas. The groups indicate the susceptibility of soil to wind erosion. 'soils ere grouped ~' according to the following distinctions: 1. Coarse sends, sands, fine sands, and very fine sands. These soils are generally not suitable for crops. They are extremely erodible, and vegetation is difficult to establish. i. Loamy coarse sends, loamy sands, loamy fine sends, Loamy very fine sands, end septic soil material. These soils ere very highly erodible. Crops can be groan if intensive measures to control wind erosion are used. 3. Coarse sandy loans, sandy looms, fine sandy loans, and very fine sandy loam s. These soils are highly erodible. Crops can be grown if intensive measures to control wind erosion ere used. 4L, Calcareous looms, silt leans, clay looms, and silty clay looms. These soils are erodible. Crops can be grovn if intensive measures to control vind erosion are used. 4. Clays, silty clays, noncelcareous clay loam s, and silty c iaY loans that are mare than 35 percent clay. Theca soils are moderetelr erodible. Crops can be groan if measures to control vind erosion are used.