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News Release

USDA Completes Initial Soil Survey of Denver County

Petra Popiel

Denver Soil Survey 2 Soil survey of Denver Feature Photo Denver Soil Survey 1

Denver, Colorado recently became the newest member of a distinctive club within the world of natural resource conservation, and more specifically, soils. It is now one of only a few major cities within the U.S. to have a modern soil survey through the National Cooperative Soil Survey program, administered by the U.S. Department of Agriculture’s (USDA) Natural Resources Conservation Service (NRCS).

The USDA appropriated its first budget to field operations for the development of soil surveys in 1899. “From the beginning, the Department prioritized the importance of understanding soils,” said Andy Steinert, NRCS Major Land Resource Area (MLRA) Soil Survey Leader in Fort Morgan and lead soil scientist for the Denver survey. “In 1935, it established the Soil Conservation Service (SCS), now the NRCS, and within the first two years, SCS published the first official soil survey manual, providing direction and procedures for all future USDA soil surveys. It truly is an honor to continue and expand upon the works and accomplishments of so many scientists before me, including those who have worked on modern soil surveys in urban areas like New York, Los Angeles, Chicago, and Detroit.”

The 1930’s Dust Bowl was one of the catalysts for the USDA to establish a higher priority on soil management, and thus mandated soil surveys across the U.S. Soil survey is a detailed report about the soils of an area. It includes maps with soil boundaries, photos, descriptions, and tables of soil properties and features. It was a tool, that could be, and still is, used to help understand and prevent how and why soils erode. Today, soil surveys are used by city and county planners, homeowners, urban farmers, gardeners and many more. They help community planners determine appropriate areas for urban expansion and land use planners determine suitable areas for recreation, landfills, highway construction, housing, or onsite sewage disposal systems. Homebuyers and developers use them to determine soil-related hazards or limitations that affect home sites, while farmers use them to help estimate potential crop or forage production. Today’s modern urban soil survey a valuable tool.

“USDA’s mandate of soil surveys was to map all the private lands around North America,” said Gene Kelly, a Professor of Pedology and Deputy Director of the Agricultural Experiment Station at Colorado State University in Fort Collins, Colorado. “Cities were not included because most of the work was focused on agriculture. Now, however, the lands that are unmapped, many of which are urban centers, have the highest density of people, and we closely engage with soils.”

Within the past decade, NRCS had placed greater emphasis on providing assistance to smaller, less rural ag landowners. Small acreage landowners, traditionally characterized by the Agency as those having less than 35 acres, had become an increasingly growing customer base in the early 2010s. As a result, NRCS established more technical and financial support for small acreage landowners and organic produce farmers. The Agency also formed the Urban Soil Focus Team in 2017.

“This new emphasis on urban areas fueled our focus on soil surveys in cities,” said Randy Riddle, NRCS Soil Scientist and national Urban Soil Focus Team Chair. “Through these surveys, we're characterizing current soil conditions and trying to capture the soil’s variability, including the degree and extent of overall alterations of the soils on the landscape.”

The Urban Soil Focus Team was established to help standardize Agency practices, improve communication, and assist development of a modern and useful soil classification system for urban soils. “Soils on any anthropogenic landscape may vary greatly in composition. As an Agency, we understood that, and had tools to assess and generate the kind of information needed for those kinds of soils,” Riddle goes on to say. “NRCS completed the New York City soil survey in 2014 which has been used as a model for other urban surveys since. Soil scientists have found that urban soils may be intact, partially changed, or completely different than those found in rural communities because of human activity. The Agency needed different tools to classify these soils.”

The NRCS has soil maps and data available providing access to the largest natural resource information system in the world. Information about soils is available online for more than 95 percent of the nation’s counties. Urban communities are part of the remaining five percent and more surveys for those areas are in the works.  “Milwaukee is next,” said Riddle.  NRCS will continue improving and modernizing older soil surveys in urban areas to keep them accurate and relevant to meet current needs.

“I'm here to see how this got done in Denver,” said Tiffany Justus, NRCS MLRA soil scientist in Illinois. “This provides me with a template to follow. We may not do things the same, but this is a great opportunity to gather some standard operating procedures we can follow in Milwaukee. If I have questions, I know who to call.”

“The process we’ve implemented in completing these surveys affords the Agency the opportunity to help reach long-term, strategic goals as well as unique training opportunities for our partners and employees,” Riddle, finally states. “Next steps include continuing to work towards completing surveys in unmapped areas. There are more cities to map. We continually work on data gaps, making improvements, updating, and modernizing substandard information. Soils are dynamic in cities; we’ve set a high bar. Our standard must be to continue improving the accuracy and usefulness of our baseline information.”