PERMFILE47530 - Laserfiche WebLink

Home Browse Search

J.S. DEPARTNENi OF AGRICULTURE NATURAL RESOURCES CONSERVATION SERVICE PHYSICAL PROPERTIES OF SOTLS Endnote -- PHYSICAL PROPERTIES OF SOILS--Continued •AGE 3 Oi 4 04/26/00 ORGANIC MAiiER is the plant and animal residue in the sail at various stages of decomposition. In report J, the estimated content of organic matter is expressed as a percentage, by weight, of the sail material that is less than 2 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 water capacity, infiltration rate, and filth. It is a source of nitrogen and other nutrients for crops. EROSION FACTOR K indicates the susceptibility of the whole soil (including rocks and rock fragments) to sheet and rill erosion by water. Factor K is one of six factors used in the Universal Soil Loss Equation (LISLE) to predict the average annual rate of soil loss by sheet and rill erosion in tons per acre per year. The estimates are based primarily on percentage of silt, sand, and organic matter (up to 4 percent) and on soil structure and permeability. Values of K range from 0.05 to 0.69. the higher the value, the more susceptible the soil is to sheet and rill erosion by water. EROSION FACTOR Kf is like EROSION FACTOR K but it is for the fine-earth fraction of the sail. Rocks and rock fragments are not considered. EROSION FACTOR i is an estimate of the maximum average annual rate of soil erosion by wind or water that can occur without affecting crop productivity over a sustained period. the rate is in tons per acre per year. N]ND ERODIBILITY GROUPS are made up of soils that have similar properties affecting their resistance to wind erosion in cultivated areas. the groups indicate the susceptibility of soil to wind erosion. Soils are grouped according to the following distinctions: 1. Coarse sands, 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. 2. Loamy coarse sands, loamy sands, loamy fine sands, loamy very fine sands, and sapric soil material. These sails are very highly erodible. Ctops can be grown if intensive measures to control wind erosion are used. 3. Coarse sandy looms, sandy loans, fine sandy looms, and very fine sandy looms. These sails are highly erodible. Crops can be grown if intensive measures to control wind erosion are used. 4L. Calcareous looms, silt looms, clay looms, and silty clay loans. These soils are erodible. Crops can be grown if intensive measures to control wind erasion are used. 4. Clays, silty clays, noncalcareous clay looms, and silty clay looms that are more than 35 percent clay. These sails are moderately erodible. Crops can be growr~ if measures to control wind erosion are used.