Description: Fields & Interpretations from NRCS SSURGOMap Unit Key [mukey]: A non-connotative string of characters used to uniquely identify a record in the Mapunit table (NRCS, Soil Data Access Soils Report).Map Unit Name [muname]: The name given to the associated geographic area (NRCS, Soil Data Access Soils Report).Hydrologic Soil Group [HydrolGrp_DCD]: There are four main hydrologic soil groups, or HSGs, that, along with land use, management practices, and hydrologic conditions, can be used to estimate direct runoff from rainfall.Group A—Soils in this group have low runoff potential when thoroughly wet. Water is transmitted freely through the soil. Group A soils typically have less than 10 percent clay and more than 90 percent sand or gravel and have gravel or sand textures. Some soils having loamy sand, sandy loam, loam or silt loam textures may be placed in this group if they are well aggregated, of low bulk density, or contain greater than 35 percent rock fragments.Group B—Soils in this group have moderately low runoff potential when thoroughly wet. Water transmission through the soil is unimpeded. Group B soils typically have between 10 percent and 20 percent clay and 50 percent to 90 percent sand and have loamy sand or sandy loam textures. Some soils having loam, silt loam, silt, or sandy clay loam textures may be placed in this group if they are well aggregated, of low bulk density, or contain greater than 35 percent rock fragments.Group C—Soils in this group have moderately high runoff potential when thoroughly wet. Water transmission through the soil is somewhat restricted. Group C soils typically have between 20 percent and 40 percent clay and less than 50 percent sand and have loam, silt loam, sandy clay loam, clay loam, and silty clay loam textures. Some soils having clay, silty clay, or sandy clay textures may be placed in this group if they are well aggregated, of low bulk density, or contain greater than 35 percent rock fragments.Group D—Soils in this group have high runoff potential when thoroughly wet. Water movement through the soil is restricted or very restricted. Group D soils typically have greater than 40 percent clay, less than 50 percent sand, and have clayey textures. In some areas, they also have high shrink-swell potential. All soils with a depth to a water impermeable layer less than 50 centimeters [20 inches] and all soils with a water table within 60 centimeters [24 inches] of the surface are in this group, although some may have a dual classification if they can be adequately drained.Dual hydrologic soil groups—Certain wet soils are placed in group D based solely on the presence of a water table within 60 centimeters [24 inches] of the surface even though the saturated hydraulic conductivity may be favorable for water transmission. If these soils can be adequately drained, then they are assigned to dual hydrologic soil groups (A/D, B/D, and C/D) based on their saturated hydraulic conductivity and the water table depth when drained. The first letter applies to the drained condition and the second to the undrained condition. For the purpose of hydrologic soil group, adequately drained means that the seasonal high water table is kept at least 60 centimeters [24 inches] below the surface in a soil where it would be higher in a natural state. (NRCS, National Engineering Handbook Chapter 7 Hydrologic Soil Groups)K-Factor [KfactRF_DCD_AL]: The soil erodibility factor K represents susceptibility of soil to erosion, transportability of the sediment, and the amount and rate of runoff given a particular rainfall input, as measured under the standard unit plot condition. Fine textured soils high in clay have low K values, about 0.05 to 0.15, because they are resistant to detachment. Coarse textured soils, such as sandy soils, have low K values, about 0.05 to 0.2, because of low runoff even though these soils are easily detached. Medium textured soils, such as the silt loam soils, have moderate K values, about 0.25 to 0.45, because they are moderately susceptible to detachment and they produce moderate runoff. Soils having a high silt content are especially susceptible to erosion and have high K values. They are easily detached and they tend to crust and produce large amounts and rates of runoff. Values of K for these soils typically exceed 0.45 and can be as large as 0.65 (NRCS, RUSLE2 Handbook 2001).Wind Erodibility Group [WEG_DCD]: A wind erodibility group (WEG) is a grouping of soils that have similar properties affecting their resistance to soil blowing in cultivated areas. The groups indicate the susceptibility to blowing. Soils are placed into wind erodibility groups on the basis of the properties of the soil surface layer. The range of valid entries for wind erodibility group data is 1, 2, 3, 4, 4L, 5, 6, 7, and 8 (NRCS, Soil Data Access Soils Report).Wind Erodibility Index [WEI_DCD]: The wind erodibility index values are assigned because the dry soil aggregates are very use-dependent on crop management factors. The wind erodibility index (I), used in the wind erosion equation, is assigned using the wind erodibility groups. Subpart B, Exhibits, Section 618.95 lists the wind erodibility index assigned to the wind erodibility groups. The lowest valid entry for wind erodibility index data is 0, and the highest is 310 (NRCS, Soil Data Access Soils Report).Drought Vulnerability [DrouVulSoi_DCD]: Even in a year, having normal precipitation or slightly less than normal, some soils are prone to having drought stress occur in the plants growing on them. Several conditions can allow this to happen. Most influential may be a relative lack of effective precipitation and typically sandy or shallow soils or soils having a high content of rock fragments. In this case, even though there may be significant rainfall, the soil matrix does not retain sufficient water for crop growth (NRCS, 2021 Annual Soils Refresh).Potential Fire Damage Hazard [FireDamage_DCD]: Slopes left denuded by forest or range fires are susceptible to accelerated erosion, flash flooding, and debris flows because of the scarcity of vegetation and roots that bind the soil and chemical changes in the soil that prevent water absorption. . Vegetation is one of the most important factors influencing erosion if the soil can allow adequate moisture entry. The vegetation helps to control erosion by shielding the soil from the impact of raindrops, by maintaining a soil surface capable of absorbing water, and by slowing the amount and velocity of runoff (NRCS, Understanding Soil Risks and Hazards).Mechanical Planting Suitability [MechPlan_DCD]: Mechanical planting treatments such as furrowing, putting, chiseling, ripping, subsoiling, flailing, mulching, shredding, and slashing can be applied to landscapes in order to improve soil permeability, reduce runoff, break-up roots, and improve vegetation conditions. The suitability for these mechanical techniques is dependent on the erodibility of the soil and the slope of the treatment area. These treatments should only be used in suitable soil conditions and applied in a way in which the potential for erosion is reduced (NRCS, Conservation Practice Standard Grazing Land Mechanical Treatment Code 548).