Land-Use, Land-Cover Survey Offers Vital Information To State

FAYETTEVILLE, Ark. — As concerns grow over the shrinking water table in the Arkansas Delta, a detailed map showing the location of water, crops and fallow land over three seasons will help farmers and government officials determine best practices for land use in the state. This digitized data will help interested parties address problems of ground water pollution and runoff, topsoil loss and salinization of surface water.

Through the Arkansas Land Use/Land Cover Project, researchers at the University of Arkansas’ Center for Advanced Spatial Technologies have brought together a vast amount of geospatial data in an easy-to-use format.

"There’s a huge potential set of analyses that can be done with this data," said Fred Limp, director of the Center for Advanced Spatial Technologies. Using information contained in the data, companies, governments and individuals can effectively plan infrastructure for future projects like irrigation, highways or company locations, and make economic and environmental assessments before committing money and time.

Digitized data from this project combined with Geographic Information Systems (GIS) may allow researchers to better target pollution reduction measures to more appropriate geographical areas, making non-point source pollution mitigation more efficient and effective, according to Michael Daniels, an environmental management specialist with the UA Cooperative Extension Service in Little Rock.

"Many agricultural service providers such as agriculture supply outlets, crop consultants, land management groups . Cooperative Extension, and others will utilize this data to generate better information about agriculture and natural resource management that in turn, will benefit landowners and farmers," Daniels said. These people may use the information for farm planning, soil and water conservation planning, irrigation planning, among other things.

The data were collected during the spring, summer and fall of 1999.

Using the database, a person can determine how many acres of wheat were grown in Craighead County, how standing water shifts from spring to summer, or where urban growth has swallowed up cropland.

The maps were created in the sky and on the ground. Research scientist Bruce Gorham and his colleagues used Global Position Systems (GPS) devices to determine their location and visited about 1,000 fields and 200 pastures over a four-week period to see what was growing at those locations.

They then entered this ground truth data from the fields into the computer, which combined the data with the satellite imagery to create a map that classifies different types of agricultural land use — pasture, corn, rice, soybean, wheat and fallow land.

"Our growing season is year-round," Gorham said. "So we have to use three seasons of imagery to determine land use at different times."

The study offers a comparison to another CAST survey of 27 counties in the Delta conducted in 1992. Gorham said that changes in forested land can be seen in the Ouachitas and Ozarks, with deforested areas showing growth and other areas becoming bare.

Researchers at CAST hope to repeat this project in five years, so they can build upon the most comprehensive agricultural map to date.

"This will serve as a basis for further studies down the road," Limp said.

The Land Use/Land Cover Project was commissioned by the Arkansas Soil and Water Conservation Commission.

For more information, please see http://www.cast.uark.edu/local/arlulc99/index.html.

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