Large-Scale Experiment Simulates Warmer Crop Weather - Wheat Grew Faster, Yields Static Or Down

[hatrack]

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Bruce Kimball, a now retired researcher, led the team of scientists from the Agricultural Research Service (ARS), the Agriculture Department's arm for scientific research, in Maricopa. A soil scientist by training, Kimball has spent a good portion of his career simulating a 2050 world in agriculture fields. In many of his past experiments, he created high-CO2 environments for plants, from sour oranges to sorghum, in what are known as Free Air Concentration Experiments, or FACE.

The heaters were turned on from December to early January, adding 2 degrees Fahrenheit during the day and 5 to 6 degrees Fahrenheit at night. Wheat was planted every six weeks over two years, a regular cycle from which the "serial" of Hot Serial Cereal comes.

As expected, the heaters accelerated growth, increased soil temperatures, reduced soil moisture, induced mild water stress on the crops and had a nominal effect on photosynthesis. But soil moisture decreased about 13 percent. "Farmers might laugh at it," said Kimball of the reactions to scientists' seemingly obvious results. For winter wheat planted in September, the heaters allowed it to withstand a substantial frost in December, a time when the plant is usually too young and feeble to bear such cold. Disastrous yield losses were avoided, thanks to the heaters.

"If that was the only experiment you did rate, you'd say, 'Bring on global warming,'" said Kimball, who published the experiment's results in the journal Global Change Biology.

But like any thorough scientist, Kimball and his team did not simply rely on the September-sown wheat to conclude the study. When heat was applied to wheat planted in December, the normal planting period for Arizona, it grew faster, with a growth cycle that was ahead by a week.

However, this fast growth meant that the grain-filling period was made shorter, and in the end, there were no major improvements in grain yields. For the crop that was planted in March, yields were much lower than what they should have been, revealing wheat's sensitivity to high temperatures.

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http://www.nytimes.com/cwire/2011/03/29/29climatewire-where-will-amber-waves-of-grain-grow-in-a-cl-81425.html