A plan for "Taking the Pollution out of Agricultural Pollution'

American agriculture seriously pollutes freshwater resources of all kinds, and reducing that pollution will require changes in the ways many farmers till their land and conduct their businesses.

There are a number of relatively simple, relatively common conservation practices already being used voluntarily by some farmers that can dramatically reduce that pollution.

Craig Cox
Craig A. Cox

But farmers today face a convergence of forces – soaring commodity prices, booming ethanol production, shifting patterns of land ownership and land lease agreements, plus a warming climate – that threaten to overwhelm voluntary efforts to reduce soil erosion and agricultural water pollution.

That was the message that Craig A. Cox, senior vice president of the Environmental Working Group, delivered in a public lecture at the University of Minnesota.

About 200 people attended the Feb. 24 presentation, the fourth in the Moos Family speaker series sponsored by the Freshwater Society and the university’s College of Biological Sciences.

“Our traditional reliance on voluntary programs simply is not strong enough to stand up against the pressures that are building on our agricultural landscape,” said Cox, who has worked on soil and water conservation for more than 20 years.

View video of Cox’s lecture.
Download a PDF of slides
he used in the lecture.

At the Environmental Working Group, Cox is senior vice president, responsible for the organization’s research and advocacy on agriculture, renewable energy and climate change. Before joining the Environmental Working Group in 2008, Cox was executive director of the Soil and Water Conservation Society for 10 years. He previously worked on agriculture and conservation issuers for the U.S. Senate agriculture committee, the U.S. Department of Agriculture’s Natural Resources Conservation Service and the National Academy of Sciences.


In his lecture, titled “Taking the Pollution out of Agricultural Production,” Cox called for:

·Rewriting the federal Farm Bill to require farmers to employ conservation strategies on their land as a condition of receiving any part of the approximately $15 billion a year in commodity payments and crop insurance subsidies the 2012 Farm Bill is likely to provide.

·Changing current laws so farmers can be required to practice conservation in places and situations where soil erosion and water pollution from agricultural runoff are most likely to occur and to cause disproportionate damage.

·Targeting public money and government-funded conservation efforts to those same types of high-risk, potentially high-reward, areas, rather than spreading financial incentives broadly among all applicants.

Craig A. Cox makes a point during his lecture

Agriculture has a huge impact on water quality partly because the industry takes up such a huge part of the landscape, affecting all the rain and snow that drain off that landscape into lakes and rivers or seep into the aquifers beneath the land. Forty-five percent of the land in Minnesota is devoted to crops or pasture, Cox said. In parts of southern Minnesota, the figure is 90 percent.


The U.S. Geological Survey has estimated that agricultural sources – corn and soybeans, other crops and pasture and rangeland – contribute 71 percent of the nitrogen and 80 percent of the phosphorus flowing to the Gulf of Mexico and contributing to the oxygen-depleted “dead zone” there. In Minnesota, a 2004 Pollution Control Agency study estimated that cropland and pasture contributed 26 percent of the phosphorus going into lakes, rivers and wetlands. That was twice the next largest source of phosphorus, atmospheric deposition.

In 2009, the Nutrient Innovations Task Force, group of U.S. Environmental Protection Agency staff and state experts on water pollution and drinking water protection, said: “Nitrogen and phosphorus pollution has the potential to become one of the costliest, most difficult environmental problems we face in the 21st Century.

Cox said a number of simple, relatively cheap conservation strategies are effective at reducing the soil, phosphorus and nitrogen washing off farm fields and draining from tile lines beneath the fields. And some farmers have long practiced those strategies voluntarily.

As examples, he cited grass filter strips planted between crops and streams, reduced tillage farming that leaves crop residue on top of the soil to control erosion and seasonal timing of nitrogen fertilizer applications to reduce runoff.

“There is a whole suite of practices that, if used more widely and used in the right locations, would have a dramatically positive effect on freshwater resources,” he said.

In a 2008 test project in Iowa, Cox said, grass strips planted at the bottom of sloping cropland reduced soil loss by 63 percent, phosphorus runoff by 93 percent and nitrogen runoff by 90 percent, even in a year of heavy rains and serious flooding.

“It really is not a technical problem,” he said, referring to the steps necessary to significantly reduce agricultural pollution.

Between 1982 and 1997, the loss of soil to erosion in the Midwestern Corn Belt was reduced significantly, Cox said. Since 1997, the loss has stabilized at about four tons per acre each year.

A provision in the 1985 federal Farm Bill requiring farmers to employ conservation measures on “highly erodible” cropland as a condition for receiving subsidy payments on those acres contributed greatly to the reduction in erosion. But the provision needs stricter enforcement, he said.

Now a number of factors – mainly economic, but also climatic — are coming together that threaten further progress on fertilizer runoff and on soil erosion, according to Cox.

The impact of climate comes, he said, from an increase in the amount of precipitation occurring in very heavy rainfalls that can greatly increase soil erosion.

The economic factors are:

·High commodity prices – $7 a bushel corn, $8 wheat and $14 soybeans at present – that encourage farmers to put marginal land into fencerow-to-fencerow crop production and tempt some to over-fertilize those crops to produce extra bushels.

·An increase in the amount of land that farm operators rent, rather than own. In Minnesota in 2007, some 58 percent of farmland was owned, and 42 percent was rented, according to the National Agricultural Statistics Service. Large, high-revenue farm operations had a much greater percentage of rented land. A boom – some say a bubble – in farmland values and rapidly rising cash rents demanded by landowners can encourage all-out production over conservation.

·Ethanol production consumed more than 30 percent of the 2010 U.S. corn crop, spurring demand for corn.

“Even some conservation-minded farmers who would like to apply some conservation practices to their leased land have to deal often with multiple landlords, sometimes with farm management companies as well,” Cox said.

To reduce erosion and water pollution from agriculture, Cox proposed two policy changes.

The first is a change in the Farm Bill, including the $7.5 billion a year crop insurance program, that would make conservation practices mandatory on all farmland, as they now are on highly erodible land. “After 25 years, I think it is time to ask farmers to do a bit more,” he said.

The second policy change, he said, should be law changes that would outlaw some particularly damaging farming practices, such as allowing livestock into streams and spreading manure on frozen ground. Some positive practices, such as filter strips between crops and streams, should be made mandatory, rather than voluntary.

“What happens on our agricultural lands – how these lands are used and managed – is absolutely essential to the sustainability of our freshwater resources,” he said.


To view video of Craig A. Cox’s lecture “Taking the Pollution out of Agricultural Production” go to www.freshwater.org. Video is also available there of the panel of Minnesota experts who appeared with Cox.

The panelists were: Dave Frederickson, the Minnesota agriculture commissioner; Gyles Randall, a University of Minnesota soil scientist; Brad Redlin, national director of agricultural programs for the Izaak Walton League; Tony Thompson, a farmer and conservationist from Windom; and Aimee Witteman, program officer for the McKnight Foundation’s Environment Program.