In July 2012, farmers in the U.S. Midwest and Plains regions
watched crops wilt and die after a stretch of unusually low precipitation and
high temperatures. Before a lack of rain and record-breaking heat signaled a
problem, however, scientists observed another indication of drought in data
from NASA and NOAA satellites: plant stress.
Healthy vegetation requires a certain amount of water from
the soil every day to stay alive, and when soil moisture falls below adequate
levels, plants become stressed. Scientists with the U.S. Department of
Agriculture’s Agricultural Research Service (USDA-ARS) have developed a way to
use satellite data to map that plant stress. The maps could soon aid in drought
forecasts, and prove useful for applications such as crop yield estimates or
decisions about crop loss compensation.