| Study: Gypsum on fields could help filter water for crops’ use |
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Study: Gypsum on fields could help filter water for crops’ use
By CELESTE BAUMGARTNER
Ohio Correspondent
WOOSTER, Ohio — Farm fields treated with gypsum are shown to have a 55 percent reduction in soluble phosphorus runoff, based on tests of water samples collected from the field’s drainage tiles.
Warren Dick, a soil scientist at The Ohio State University’s College of Food, Agriculture and Environmental Sciences, is two years into a three-year study of gypsum’s benefits on farms, including improvements in soil quality, yields and reducing phosphorus runoff.
“I’ve been studying beneficial uses of gypsum for about 20 years, using it on very highly degraded coal mine lands, and we found some positive results,” Dick said. “It was natural to move into agriculture, and one of the things we found was that it did keep valuable phosphorus in the field instead of allowing it to run off in the tile drains.”
Joe Nester, owner of Nester Ag, LLC, an agricultural consulting business, is providing Dick with fields for testing. He gets the gypsum as a byproduct from power plants that have scrubbers. Nester found comparable farm fields where he could segregate the tile water underneath fields treated with gypsum from the tile water from the untreated fields.
“Every time we get a rain event, we check and see if the tile is running,” Nester said. “If the tile is running, we take samples from each treatment and send them to the laboratory (that data is sent to Dick).
“Immediately there was a drastic difference in the turbidity of the water. The gypsum soils, those tiles ran very clean, clear water. The non-treated tiles ran muddy water. That is still happening 2.5 years after the treatment of the gypsum.
“We’re up close to 200 samples now off of 10 different fields and we are still averaging over a 50 percent reduction in the phosphorus in the water out of the tile by the area that was treated with gypsum, compared to the area that was not treated,” Nester added.
Dick is continuing to get a better understanding of exactly what is happening when gypsum is applied to a field. The effects can last 20 months. Although he has not yet correlated the data, he suspects it may last even longer on some soils.
Also, as a result of the U.S. EPA’s Clean Air Act, acid rain has been reduced, he said. That means less sulfur is being deposited on the soil through rainfall. No one wanted the pollution but, in one sense, he said it had benefits. The higher crop yields are taking more sulfur out of the soil every year.
“Now farmers are reporting that they’re having deficits in sulfur and are getting responses to sulfur fertilizer applications,” Dick said. “Gypsum has been used for a long time as a sulfur fertilizer or nutrient source.”
Gypsum can also provide calcium for soil quality improvements, he said. Calcium tends to make the soil more open. It combines small particles and makes them into larger particles; it aggregates the clay. That improves water infiltration and aeration and affects growth.
“Farmers may not see the effect the first year unless they have a sulfur deficiency, but over time, because of that better rooting of the crop, they are reporting better crops responses,” he explained.
Dick has two caveats for the use of gypsum: farmers still need to apply lime on acid soils, since gypsum is not a liming material; also, like any amendment, too much gypsum is not good. |
| 12/17/2014 |
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