Celebrating the Next Generation

"I hope the answer to your question is clearly indicated in what I have written. It is that the soil survey will never be completed because I cannot conceive of the time when knowledge of soils will be complete. Our expectation is that our successors will build on what has been done, as we are building on the work of our predecessors."

The above quote is from a letter by R. S. Smith in response to the Comptroller of the University of Illinois' request for an estimate of the cost to complete the soil survey of the state. That was nearly 70 years ago! A response today would be quite similar!

STATE- OF-THE-ART??

We now have soil survey information available for all of Illinois. This data has been gathered over the last 45 years, on a county by county basis, and reflects what was known about the soils at the time of the survey. The published soil survey reports are excellent sources of information, but they have become outdated to varying degrees as new information about soils is gathered, and as demographics, technologies, environmental concerns, and intensities of land use have changed.

New techniques have been developed and improvements have been made in the use, interpretations, and presentation of soil survey information. Each survey area, as surveyed, was state-of-the-art at that time. But what was state-of-the-art then and what is state-of-the-art today is obviously much different.

There is a broad-based demand for, and use of, soil survey information throughout Illinois. That demand is increasing, and users want resource information data layer like the soil survey, incorporated into geographic information systems (GIS).

PLAN TO UPDATE THE SOIL SURVEY

There is a need to bring the patchwork of county soil surveys to a common standard, to build on the existing information, and to develop a coordinated database to address state, regional, and national concerns. The approach for updating and maintaining "modern" soil surveys will be to assume that we have a good product to start with. So, the job of updating soil surveys will not necessarily be to produce an entirely new survey, but to, where possible, upgrade the existing survey be refining and enhancing it.

The update of an existing soil survey may take one of several forms depending on the accuracy, precision, and usefulness of the original survey. All update activities will be managed by Major Land Resource Area (MLRA).

MLRA CONCEPT

In the 1960's USDA divided the United States into land resource regions (LRR) and major land resource areas (MLRA). This system affords a basis for making decisions about national and regional agricultural concerns, provides a broad base for extrapolating the results of research and resource inventories within national boundaries, and serves as a framework for organizing and operating resource conservation programs. The 24 land resource regions of the USA have been divided into 212 MLRA's. MLRA's are geographically associated areas that are characterized by a particular pattern of soils, climate, water resources, and land uses. Parts of 12 MLRA's in 5 LRR's cover Illinois. Some of the MLRA's have been subdivided into land resource units.

The soil survey area of the future will be the MLRA, not an individual county, as in the past. Soil survey identification legends, taxonomic and map unit descriptions and correlation activity will be on an MLRA basis. Soil maps will join across political boundaries (county and state) line for line, map symbol for map symbol, map unit name for map unit name, and soil interpretation for soil interpretation. The objective of all MLRA soil survey update activities will be to provide an improved product on a controlled base, that can be used in a geographic information system (GIS). Significant improvements expected include:

• A uniform map scale and mapping intensity for the MLRA
• A common standard of documentation.
• Better description of composition and pattern of soils in map units
• More precise statements about the expected reliability of maps and interpretations.
• New soil property data and interpretations.
• A coordinated database of soil properties.
• A digital soils data layer meeting national map accuracy standards.

12K DIGITAL SOIL SURVEY

The following guidelines will be used to produce a 1:12,000 (12K) digital soil survey for Illinois:

• Survey Area is the MLRA with county projects as possible subsets
• Base will be USGS digital orthophoto quarter quads (DOQ)
• Scale of the DOQ's is 1:12,000
• Legend will be an MLRA legend with a typical pedon described for each taxonomic unit and map unit in the MLRA
• Documentation is required in order to make unbiased, statistically reliable statements of map unit composition. This will require transects and descriptions throughout the MLRA in addition to any fieldwork that may be needed in county subsets.

• Product will be a coordinated, joined, digitized soil survey on a 1:12,000 orthophoto quarter quad base. Both hard copy and digital information will be produced. Eventually, a soil survey map series (similar to USGS's topographic map series) will be available in digital form.

COST

The estimated cost of updating and digitizing the soil survey of Illinois is $25 million, as follows:

• digital orthophotography $ 2.5 million
• soil survey database activities 3.7
• soil survey field activities 11.3
• soil survey compilation and digitization 7.5
• $ 25 million Total

STATUS

Ten update projects are now underway and there are a dozen other counties considering cost share agreements. Soil survey users need more, want more, and expect more from the soil survey. The soil survey partnership is dedicated to delivering a quality product.