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Scientists Eye Farm Uses of Landsat 7 Imagery
By Marcia Wood
April 16, 1999
Information beamed to earth from the Landsat 7 satellite launched from California yesterday will be eagerly scrutinized by Agricultural Research Service scientists.
Researchers in Arizona are exploring ways that growers and land managers of the future could routinely use imagery from satellite data for precision farming, sometimes called foot-by-foot management. The imagery might help growers answer crucial questions in time to act quickly to prevent crop losses or bolster profits. For example, are crops getting enough water? Are they under attack by diseases?
At the U.S. Water Conservation Laboratory in Phoenix, Ariz., ARS physical scientist M. Susan Moran and colleagues are improving a method for combining data from five satellites. Landsat 7's on-board sensor will supply two forms of data--heat emitted from and light reflected by plants and soil, for example. The other data are from radar sensors on four other satellites.
The heat, light and radar-based technologies complement each other and should open the door to providing useful imagery to growers on a daily basis, according to Moran.
Landsat 7 will pass over a given spot only once every 16 days, but the gaps can be filled by radar data collected nearly every day. On overcast days, radar can "see" through clouds that thwart Landsat 7. And Landsat's eight-band sensor provides more detailed crop and soil information than the one-band radar sensors.
Landsat 7 is expected to provide more accurate data--and with a faster turnaround--than its predecessor, Landsat 5.
The National Aeronautics and Space Administration is funding part of Moran's work. She is a member of the Landsat 7 science advisory team and the principal ARS scientist for Landsat 7. Other ARS scientists in Arizona and ARS labs in Beltsville, Md., will also conduct experiments with Landsat 7 imagery. ARS is USDA's chief research agency.
Scientific contact: M. Susan Moran, ARS U.S. Water Conservation Laboratory, Tucson, Ariz; phone (520) 670-6380, ext. 171; fax (520) 670-5550; moran@tucson.ars.ag.gov, http://www.tucson.ars.ag.gov/rsg/landsat.
