USDA Tests Climate Change Impact on Arizona Wheat

(USDA.gov)

Scientists at the U.S. Department of Agriculture’s (USDA’s) research center in Maricopa, Arizona devised a method of testing the potential impact of warming temperature from climate change on the wheat crop in the U.S. southwest. The technology and the results are discussed in the February issue of USDA’s Agricultural Research magazine, and earlier in the journal Global Change Biology.

At USDA’S Arid-Land Agricultural Research Center, scientists built a system to simulate growing conditions expected in the year 2050, given current climate change projections. The technology, known as Temperature Free-Air Controlled Enhancement (T-FACE), features infared heaters suspended over open fields, and enables scientists to raise the air temperature at experimental plots.

For this study, scientists planted wheat every six weeks between March of 2007 and May of 2009 and applied heat to six of 15 plantings, warming the crops planted each year in March, December, and September. They measured canopy conditions to ensure daytime temperatures in the heated plots rose by 2.7 degrees Fahrenheit and nighttime temperatures rose by 5 or 6 degrees. Wheat is normally planted in Arizona in mid-winter, harvested in late May and irrigated throughout its growing season.

The results showed warming the test plots had effects on the wheat, but the impacts on yields depended on when the wheat was planted. Where the T-FACE heaters increased the air temperatures, researchers found accelerated growth of the test wheat, increased soil temperatures, reduced soil moisture, mild water stress on the crops, and a nominal effect on photosynthesis.

But the impact on yields depended on the timing of the tests. When heat was applied to wheat planted in mid-winter, it grew faster, with a growth cycle that was ahead by a week, but there were no major differences in yield. Adding heat to wheat planted in September, however, enabled the wheat to survive frosts between Christmas and New Year’s both years with only moderate yield loss. Wheat planted at the same time in the unheated plots yielded nothing.

Read more: USDA Funding Research on Climate Change, Agr Production

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