Soil Survey Geographic Database

Soil Survey Geographic Database
Name	Soil Survey Geographic Database
Abbreviation	SSURGO
Country	United States
Maintained by	United States Department of Agriculture Natural Resources Conservation Service
Established	1990s
Data type	digital soil survey
License	public domain

Contents

Soil Survey Geographic Database

The Soil Survey Geographic Database is a digital cartographic and attribute database used for mapping soil types in the United States; it supports planning by agencies such as the United States Department of Agriculture, Environmental Protection Agency, United States Geological Survey, National Oceanic and Atmospheric Administration and state agencies like California Department of Water Resources and New York State Department of Environmental Conservation. It integrates legacy work from organizations including the Soil Conservation Service and collaborations with academic institutions such as Iowa State University, University of California, Davis, Colorado State University, Texas A&M University and University of Minnesota. The database underpins projects by conservation programs like the Conservation Reserve Program and research by agencies such as the United States Forest Service and international partners including the Food and Agriculture Organization.

Overview

The database provides spatial delineations and attribute tables of soil mapping units across the United States and territories; it is built to be interoperable with systems used by the United States Geological Survey, National Aeronautics and Space Administration, Environmental Systems Research Institute, University Corporation for Atmospheric Research and state geospatial clearinghouses. Key outputs include polygon coverages, component tables, horizon data and interpretive ratings used by programs like the National Resources Inventory and planning frameworks from the Department of the Interior and Federal Emergency Management Agency.

Development traces to the digitization efforts of the Soil Conservation Service in the late 20th century and formalization under the Natural Resources Conservation Service during the 1990s, with influences from national initiatives such as the National Spatial Data Infrastructure and collaborations with mapping projects like the National Hydrography Dataset and the National Land Cover Database. Major milestones include the transition from analog field maps used by state offices in Pennsylvania, Iowa, Kansas, and Georgia to standardized digital schemas adopted by the National Cooperative Soil Survey and integration with federal metadata standards promoted by the Federal Geographic Data Committee.

The schema organizes information into interconnected tables: spatial units (polygons), component descriptions, horizon series, texture, drainage class, and interpretive data such as land capability classes used by the Natural Resources Conservation Service and agronomic extensions at Cornell University and University of Illinois Urbana–Champaign. Attribute fields align with standards from the Federal Geographic Data Committee and are consumable by software from Esri and open-source projects supported by Open Geospatial Consortium members and repositories at National Centers for Environmental Information.

Field mapping methods derive from protocols developed by the National Cooperative Soil Survey and training curricula at institutions like North Carolina State University and University of Wisconsin–Madison. Techniques include stratified reconnaissance, transect sampling, auger and pit description, laboratory texture analysis performed in state soil laboratories, and georeferencing with technologies from Trimble and Garmin. Quality control employs review procedures aligned with standards from the Federal Geographic Data Committee and peer review practices common to programs at the Smithsonian Institution and university extension services.

Users apply the database for agricultural planning used by Farm Service Agency programs, infrastructure siting by agencies such as the Federal Highway Administration, flood risk assessment by the Federal Emergency Management Agency, and ecosystem modeling conducted by teams at the United States Forest Service and National Aeronautics and Space Administration. Academic research at institutions including Michigan State University, Oregon State University, University of Florida, and Pennsylvania State University uses the dataset for soil carbon studies, hydrologic modeling, nutrient management, and urban planning in cities like Chicago, Los Angeles, Houston, and New York City.

Data distribution is managed by the Natural Resources Conservation Service through platforms interoperable with the National Map and state geospatial portals operated by entities such as the California Spatial Information Library and the Texas Natural Resources Information System. Delivery formats include geodatabases compatible with Esri ArcGIS and formats consumed by open-source tools from the QGIS project. Collaborative initiatives with the United States Geological Survey and the National Aeronautics and Space Administration facilitate integration into web mapping services and cloud-hosted repositories.

Limitations include variable mapping resolution among counties such as those in Alaska versus the Midwest, legacy attribute inconsistencies carried over from historical surveys, and the need for updated field verification under changing climate conditions studied by National Oceanic and Atmospheric Administration programs and university climate centers. Future directions point to integration with high-resolution remote sensing from Landsat, Sentinel-2, and lidar collected by programs at the United States Geological Survey and National Aeronautics and Space Administration, adoption of improved digital soil mapping methods advanced by research groups at University of Southampton and CSIRO, and enhanced interoperability with initiatives like the Global Soil Partnership.