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Soil Map Units and Components. Building Blocks of Soil Survey. What is a Map Unit?. A collection of delineations or polygons on a map with similar pattern of landform, slope, soils, and other site characteristics Assigned the same symbol on the map
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Soil Map Units and Components Building Blocks of Soil Survey
What is a Map Unit? • A collection of delineations or polygons on a map with similar pattern of landform, slope, soils, and other site characteristics • Assigned the same symbol on the map • Delineation size and base map scale are relevant to the various uses
Map Unit Naming Conventions • Alaska Technical Note 13 • Detailed surveys (Order 2) • Based on soil series • 24KN33-Knik silt loam, steep and sloping • Detailed Reconnaissance surveys (Order ¾) • Based on life zone or biome, landform, and other significant site properties • D22FPC-Boreal Schist Flood Plains and Terraces with Common Permafrost
Components • Unique combination of soil and site characteristics • Exist in most delineations of map units assigned • Add to the understanding of the map unit • Are contrasting (interpret differently) to all other components in the map unit • Allow for useful and significant soil data and interpretations to the users • Naming conventions Alaska Technical Note 13
Components • Are contrasting (interpret differently) to all other components in the map unit • Urban uses • Slope, slope length, substratum texture and rock fragment content • Wildland uses (potential natural community) • Surface texture and rock fragment content, elevation and climatic gradients • Interpretive slope groups are more broadly defined
A component is a unique combination of soil and site Example of the soil portion of a component (Order 2) Knik silt loam 30 to 60 cm of loess over sand and gravel
(0 -12% slopes) (12 -35% slopes) Example of the site portion (Order 2) • Slopes influence a variety of ag and urban interpretations • Components based on slope must be predictable on the landscape and provide interpretive significance 24KN32-Knik silt loam, gently sloping and moderately steep
(0 -35% slopes) Component example (Order 3-4) • Slopes up to 35 percent do not influence interpretations for wildlife habitat • PNC is important and influenced by surface rock fragment content, wetness, flooding , and gradients of elevation and climate D24PL1-Knik silt loam, 0 to 35 percent slopes
Map units and components summary • Designed is based on current or projected land use • Naming conventions and coding protocols are outlined in Alaska Technical Note 13