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Custom Soil Resource Report <br /> Soil Qualities and Features <br /> This folder contains tabular reports that present various soil qualities and features. <br /> The reports(tables)include all selected map units and components for each map unit. <br /> Soil qualities are behavior and performance attributes that are not directly measured, <br /> but are inferred from observations of dynamic conditions and from soil properties. <br /> Example soil qualities include natural drainage, and frost action. Soil features are <br /> attributes that are not directly part of the soil. Example soil features include slope and <br /> depth to restrictive layer.These features can greatly impact the use and management <br /> of the soil. <br /> Soil Features (Russell Painter ) <br /> This table gives estimates of various soil features.The estimates are used in land use <br /> planning that involves engineering considerations. <br /> A restrictive layeris a nearly continuous layer that has one or more physical,chemical, <br /> or thermal properties that significantly impede the movement of water and air through <br /> the soil or that restrict roots or otherwise provide an unfavorable root environment. <br /> Examples are bedrock, cemented layers, dense layers, and frozen layers. The table <br /> indicates the hardness and thickness of the restrictive layer,both of which significantly <br /> affect the ease of excavation.Depth to top is the vertical distance from the soil surface <br /> to the upper boundary of the restrictive layer. <br /> Subsidence is the settlement of organic soils or of saturated mineral soils of very low <br /> density. Subsidence generally results from either desiccation and shrinkage, or <br /> oxidation of organic material, or both, following drainage. Subsidence takes place <br /> gradually, usually over a period of several years. The table shows the expected initial <br /> subsidence,which usually is a result of drainage, and total subsidence, which results <br /> from a combination of factors. <br /> Potential for frost action is the likelihood of upward or lateral expansion of the soil <br /> caused by the formation of segregated ice lenses (frost heave) and the subsequent <br /> collapse of the soil and loss of strength on thawing. Frost action occurs when moisture <br /> moves into the freezing zone of the soil. Temperature, texture, density, saturated <br /> hydraulic conductivity (Ksat), content of organic matter, and depth to the water table <br /> are the most important factors considered in evaluating the potential for frost action. <br /> It is assumed that the soil is not insulated by vegetation or snow and is not artificially <br /> drained. Silty and highly structured, clayey soils that have a high water table in winter <br /> are the most susceptible to frost action.Well drained,very gravelly,or very sandy soils <br /> are the least susceptible. Frost heave and low soil strength during thawing cause <br /> damage to pavements and other rigid structures. <br /> Risk of corrosion pertains to potential soil-induced electrochemical or chemical action <br /> that corrodes or weakens uncoated steel or concrete. The rate of corrosion of <br /> uncoated steel is related to such factors as soil moisture, particle-size distribution, <br /> acidity,and electrical conductivity of the soil.The rate of corrosion of concrete is based <br /> mainly on the sulfate and sodium content,texture, moisture content,and acidity of the <br /> soil. Special site examination and design may be needed if the combination of factors <br /> results in a severe hazard of corrosion. The steel or concrete in installations that <br /> intersect soil boundaries or soil layers is more susceptible to corrosion than the steel <br /> 25 <br />