COLUMBUS, Ohio - Changes in farming practices have played a major role in improving water quality in Lake Erie, a recent study suggests. Farm-based pollution has dropped by as much as 50 percent in the region.
An Ohio State University researcher compared pollutant emissions in 1985 to those 10 years later for two watersheds that drain into the lake. He then compared those results to how farming practices changed in the area during the same time.
Water quality improved with the adoption of farming practices that reduced the amount of fertilizers and chemicals draining from farmers' fields into the lake.
"Farmers in this area began using more conservation practices during the last two decades, which resulted in an overall decrease in agricultural chemicals washing into Lake Erie," said D. Lynn Forster, study author and a professor of agricultural, environmental and development economics at Ohio State.
Farm-related pollution levels in Lake Erie decreased anywhere from 5 percent to more than 50 percent in a 10-year period.
The most striking change in farming practices was the rapid adoption of conservation tillage in both watersheds. Conservation tillage is any tilling practice that leaves 30 percent of the field covered with residue from the previous crop. In traditional, or conventional, tilling, the farmer tills the previous crop completely, leaving fresh soil vulnerable to erosion. In 1985, only 5 to 14 percent of the farms in northwestern Ohio used conservation tillage, compared with 50 percent which did so in 1995. Lynn suspects the percentage has remained about the same.
Forster's research appears in a recent issue of the Journal of Soil and Water Conservation.
Forster analyzed the agricultural practices of 450 farms in 19 counties located in the Maumee and Sandusky river watersheds in northwestern Ohio. The area is a good representative of farmland in the United States, Forster said. The watersheds contain about half of the total cropland that ultimately drains into Lake Erie. Each farm included in the study had a gross annual income of at least $40,000. This income represented commercial farming and excluded rural residents with only a peripheral interest in farming.
Forster also analyzed the effectiveness of 19 federal and state government-sponsored farm incentive programs. Most of these provide financial incentives to encourage farmers to adopt conservation practices to better protect the environment. Between 1987 and 1997, federal and state agencies spent about $143 million on such programs in northwestern Ohio. Each farm participating in such a program received an average of $7,000, or about $2 per acre each year. Individual allocations ranged from more than $3.40/acre each year (three counties) to as little as $0.30 to $1/acre per year (nine counties).
Using a computer model, Forster simulated the predicted 10-year reduction in pollutants washing into Lake Erie from the watersheds due to these farming conservation programs. He then compared those estimates to actual changes in pollution as measured by other researchers. While the computer model consistently over-predicted the reduction of all but one of the pollutants, the computer-generated data did correspond with changes in actual pollutant levels in the lake.
Actual water testing revealed that in the Sandusky River, both nitrogen and suspended solids decreased by about 20 percent in a 10-year period, while phosphorus decreased by about 53 percent. In the Maumee River, suspended solid levels decreased by about 5 percent; nitrogen decreased by about 15 percent; and phosphorus by about 48 percent. However, in both rivers, nitrate levels increased by about 10 percent.
And while the conservation tillage that most farmers in the area adopted resulted in less soil erosion and decreased pollutant levels in waterways, it also helped increase farm profits.
"Environmental benefits aside, conservation tillage let some of the farms become larger and more specialized. That resulted in improved profits," Forster said. "So it makes sense that farmers would want to adopt conservation practices."
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