Iowa State University

Inside Iowa State
May 15, 1998

Keeping tabs on the land

by Skip Derra

A sense of history and a love for fly fishing help focus Dean Thompson when it's time to take stock of our nation's natural resources.

As director of the Natural Resources Inventory and Analysis Institute, a division of the U.S. Department of Agriculture's Natural Resources Conservation Service, Thompson is in charge of the largest survey of natural resources in the country.

An archaeologist by training and fisherman by choice, Thompson oversees the National Resources Inventory (NRI), a survey that assesses the vitality of soil, water and other resources in the United States. The NRI is a statistical- based sample of land use and natural resource conditions and trends on non-federal lands. The database, which represents 1.5 billion acres or approximately 75 percent of all U.S. land, is the most comprehensive database of its type in the world.

NRI data have been used to develop the 1996 Farm Bill, assess the effectiveness of the Conservation Reserve Program and monitor urban areas, farmland and wetlands. It provides the scientific basis on which many Congressional committees formulate land use policy, and is available to any U.S. citizen.

"The need for consistent natural resource information is burgeoning," said Thompson, who has been at Iowa State since 1989. "Everybody needs that kind of view. Everybody wants to use an estimate that has science behind it. People want to find out how serious problems are and how they're changing through time."

Filling this growing need is the NRI.

"Ours is the only nationally consistent survey of natural resources," he said. "It is a scientific study. Many others are not."

Much of the science behind the NRI, Thompson said, comes from Iowa State's Statistical Laboratory, a part of the statistics department. Established in 1933, it was the first statistical center of its type in the country, bringing together people trained in statistical theory and application.

"The science and expertise in the stat lab is without equal, and it lends to the science, credibility and reputation of the NRI," Thompson said. In addition to tabulating and working the numbers, the stat lab has a hand in designing the survey to make sure that it provides as complete a picture of U.S. land as possible.

"The survey is designed so you can have a national view, a multi-state view, or a substate or multi-county view," Thompson said. "And all of the parts add up."

The 1997 NRI is the fourth such survey. It repeats surveys in 1982, 1987 and 1992. Data still are being collected for the 1997 survey, which will be released in 1999.

The survey requires a large effort. About 500 data collectors amass the information. Painstaking time and care are taken in measurements, reading field reports and scrutinizing aerial photographs of specific points in the United States.

Data collected include information on soil characteristics, land use, soil erosion, vegetative cover and ecological variables such as habitat diversity.

Collectors note bodies of water, streams and rivers, buildings and roads. They chart land reverting back to wetlands and land that is being farmed. Information can be as specific as changes in the types of crops planted on a farm and the effects those crops have on the health of the soil, Thompson said.

To obtain information, Thompson relies on several labs throughout the country. One such lab, which covers Iowa and Missouri, is in Ames.

The Ames survey lab employs 20 people who monitor nearly 16,000 quarter-mile-square sampling units. They began in August 1997 and plan to complete work by July 1.

Thompson said the survey may become an annual task in 1999, making the data more relevant.

Thompson began his career at NRCS as an archaeologist examining the effects of agency programs, like large water projects such as dams, on cultural resources. He also has studied ancient soil erosion in the Loess Hills of western Iowa.

It is the fragility of the Loess Hills and other environmentally delicate areas across the United States, coupled with a perspective gleaned from hours of casting a line while thigh-deep in water, that give Thompson an appreciation for taking stock of what's under our feet.

"I'm concerned with the entire planet in terms of the health of the land and water, and how we socially try to understand that," he said. "The NRI provides a national picture of that health and describes what has happened."

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