Scientists Are “Blown Away” by Blustery Research
Kids have always liked to play with toy farms.
Scientists at the Agricultural Research Service (ARS) like toy farms, too!
Two scientists at the ARS National Soil Tilth Laboratory in Ames, Iowa, have built a model farm in the basement of their building. But they’re not playing around—they’re using it to study how air currents travel across farmlands.
It’s important to know how air currents move, because they pick up odors and dust that can be a problem. (If you’ve ever been downwind of a pig farm, you’ll understand!) Buildings and other structures on a farm affect how air currents travel the same way that water in a stream goes around rocks and other obstacles in the streambed.
The scientists, Tom Sauer and Jerry Hatfield, wanted to find out if buildings protect manure-storage facilities and lagoons from the wind—or if buildings interrupt the air flow in a way that increase wind speed and turbulence.
This information could help farmers figure out where to build barns and other structures to help slow down or limit the flow of air currents over manure storage areas like pits or lagoons. Then the odors and dust from manure and farmyards couldn’t travel as far or as fast.
Tom Sauer and Jerry Hatfield built their “farm” inside a 40-foot tunnel. The “wind” is made by a blower at the end of the tunnel. It can blow up to 30 miles per hour—as strong as a brisk breeze that snatches an umbrella right out of your grasp!
The farms have tiny “barns” and “trees.” The scientists use the same kind of “grass” that people use in model railroad displays. They even make “lagoons” from cups of water or smoke from dry ice.
Special instruments are used to track where the wind is going and how far it travels. A black-and-white checkerboard pattern on the walls makes a grid that the scientists can use to measure distance. Each square is 6 inches square. It’s similar to a ruler, only much bigger.
Their tiny model showed that farmers who consider airflow patterns when they build their barns might be doing their neighbors—and themselves—a big favor. Using their wind tunnel, Sauer and Hatfield figured out that if farmers build their barns and other buildings parallel to airflow, the wind won’t carry the odors as far. So the smells don’t travel as far, and they don’t create a nuisance to their neighbors. If the buildings are placed perpendicular to airflow, the currents can be slowed down by as much as 67 percent!
So if you see some scientists in a toy store, just remember they might actually be hard at work finding ways for farmers to keep the air as clean as possible!––By Ann Perry, Agricultural Research Service