Soil Mapping

Soil Surveys are three-dimensional depictions of a landscape. It is the third dimension — what lies below the ground — that is usually the most mysterious. Unfortunately, the axiom "a picture is worth a thousand words" doesn't work well with soils. Yet, the soil underlying a site is usually the most crucial dimension to understand in order to predict the suitability of a project for any particular property.

Fortunately, a well-prepared soil map can provide the user with a tool to better understand the limitations of a given site. It does this by placing similar soils with similar diagnostic properties into one of many "series." Information endemic to this series, collected over time by the USDA Natural Resources Conservation Service, can then be reviewed and implemented for the betterment of the project and environment.

To make a soils plan easier to understand, series "phases" are used to further define a soil in terms of commonly understood descriptors. For example, the soil map shown above describes each type of soil by its drainage class phase, its series name, its surface texture phase, and its slope phase. Elsewhere, another phase is used to show areas where the surficial soil began to undergo sheet erosion as a consequence of certain land use practices a generation ago. (Some mapping units are colored to highlight other potentially constraining soil properties at this particular site.)