Resources at Risk
|
Archived Articles
Species on the Brink
Resources at Risk
Good News
Get Outdoors |
Satellites Aid Lake Quality Monitors MADISON, Wisconsin, January 27, 2003 (ENS) - Remote sensing using satellites could help monitor water quality and crop fertilization, according to two teams of scientists. University of Wisconsin-Madison researchers and their cooperators have developed a method of assessing the water quality of Wisconsin's lakes from space. Using images captured 438 miles above the earth, they have completed the first satellite based inventory of the clarity of the largest 8,000 lakes in the state.
"Our research aims to integrate satellite data into the state's day to day lake management programs," said Thomas Lillesand, who led the effort as director of UW-Madison's Environmental Remote Sensing Center. "This won't eliminate the need for conventional water quality monitoring, but it will greatly increase the benefits of ground based sampling." The researchers hope to monitor lake clarity over time to learn "where lake management activities might be most useful, and which lakes will be most subject to change in the future due to such factors as changes in land use and climate," Lillesand added. The new statewide water clarity map, daily satellite images of Wisconsin, and an electronic gallery of Landsat images of Wisconsin lakes are viewable online at: http://www.ersc.wisc.edu Today's wheat growers also face many environmental challenges, including the use of fertilizer. Growers need to apply enough nitrogen based fertilizer to achieve the highest possible crop yields without over-applying - a situation that could lead to serious environmental effects. In wheat, a critical factor comes down to timing in order to determine how efficiently plants will use nitrogen fertilizer. Current methods for determining the optimum timing of nitrogen fertilizer application can be difficult, expensive and time consuming. To assist wheat growers, scientists at North Carolina State University have developed a technique to time nitrogen fertilizer applications using remote sensing, including aerial photography and satellite imagery. "This is one of the first applications of remote sensing technology for nitrogen management available to growers," said Michael Flowers, project scientist. "With the ability to cover large areas in a quick and efficient manner, this remote sensing technique will assist growers in making difficult nitrogen management decisions that affect profitability and environmental stewardship." In this 2000-2001 study, scientists used remote sensing in the form of infrared aerial photographs to determine when early nitrogen fertilizer applications were required. By relating the infrared reflectance of the crop canopy to wheat tiller density, the scientists were able to differentiate wheat fields that would benefit from early nitrogen fertilizer applications compared to wheat fields that would benefit from standard nitrogen fertilizer applications. The remote sensing technique was found to accurately time nitrogen fertilizer applications 86 percent of the time across all field locations. The results of the study appear in the January/February 2003 issue of "Agronomy Journal," available online at: http://agron.scijournals Copyright Environment News Service (ENS) 2002. All rights reserved. |
Autumn sunset on Wisconsin's Turtle Lake (Photo courtesy 