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Researchers replicate climate change to forecast its effects
USDA-ARS scientists are
replicating the effects of climate change to see what the future holds for
soybeans, wheat, and the soils where the plants grow.
Soybeans, wheat, and a
number of other crops grow more when carbon dioxide levels are elevated because
the increased carbon is thought to give the plants more food. But those same
plants are damaged and stunted by elevated levels of ozone, a ground-level gas
created when sunlight heats up automotive and industrial pollutants. Levels of
both gases are expected to rise as the climate warms.
Fitzgerald Booker, Kent
Burkey, and Edwin Fiscus, researchers at the ARS Plant Science Research Unit in
Raleigh, North Carolina, are using 16 open-top chambers to expose wheat and
soybeans to the levels of carbon dioxide and ozone that may be reached by 2050.
By that time, carbon dioxide levels may be about 1.5 times greater than the
current 380 parts per million. Daytime ozone levels in the summer, now at about
50 to 55 parts per billion, may rise 20%. The goal of the study is to assess
the effects of climate change on growth rates, crop yields, and soil chemistry.
The researchers have four
sets of four chambers: a set with elevated ozone, a set with elevated carbon
dioxide, a set with both gases elevated, and a set with four control chambers
without elevated levels of either gas.
They also are leaving plant
stems, empty pods, and dead leaves in the chambers, and they are not plowing
the soil to mimic conditions found in no-till farming. In this type of cropping
system, elevated carbon dioxide levels may increase soil decomposition and slow
down the accumulation of carbon in the soil.
Preliminary results show
just slightly higher levels of soil carbon in chambers with elevated carbon
dioxide and in chambers with elevated levels of both carbon dioxide and ozone,
but not in chambers with elevated ozone alone. Elevating carbon dioxide also
reduced flour protein levels in wheat by 7% to 11%. But soybean protein
concentrations were maintained because of soybeans’ ability to acquire nitrogen
from the air.
ARS Information Staff
5601 Sunnyside Avenue, Beltsville, MD 20705-5128