Plant stress occurs when soil moisture falls below levels required daily to keep vegetation alive and healthy, scientists said.
Now researchers with the U.S. Department of Agriculture say analysis of data from satellites operated by NASA and the National Oceanographic and Atmospheric Administration has allowed them to created detailed maps of areas most vulnerable to plant stress.
Drought forecasts would be the most immediate benefit of such maps, the researchers said, but they could also help farmers make crop yield predictions or aid government decisions about crop loss compensation.
"Crop drought monitoring is of high practical value, and any advance notice of drought conditions helps the farmer make practical decisions sooner," Steve Running, an ecologist at University of Montana, said in a NASA release Wednesday.
The plant stress maps confirm drought in 2012 has been more widespread and damaging than any in the last 25 years, the USDA's Economic Research Service said.
"2012 was record-breaking, this was just a huge event," said USDA researcher Martha Anderson, who is one of the agricultural scientists working to develop the plant stress indicator for drought.
"We think there's some early-warning potential with these plant stress maps, alerting us as the crops start to run out of water," she said. "Signals of plant stress may often appear first in satellite-derived maps of vegetation temperature before the crops have actually started to wilt and die.
"The earlier we can learn things are turning south, presumably the more time we have to prepare for whatever actions might be taken."