Farmers Fight Global Warming with No-Till Farming
On one field, there is only rich, lumpy black earth, free of weeds or debris, below the rows of cornstalks waving gently in the breeze. On another field, you can hardly even see the dirt below a thick layer of woody residue -- dried-up bits of corn cobs, pieces of stalk up to eight inches long, even the crumbly remains of the soybean plants that typically alternate with corn crops on Midwestern fields.
A city dweller might think the difference is the matter of a lazy or preoccupied farmer. But in reality, the messier-looking field is an example of a practice that could play a significant role in reducing global warming.
The first field is tilled with a standard plow, a massive machine towed by a tractor that grabs the earth and turns it over completely, removing the residue of past crops. The second field is a "no-till" plot, meaning it was not plowed but rather the new crop was planted amidst the waste of the old. There are also "partial till" plots, in which a special plow that turns over the soil to a lesser degree than the standard one is used.
When a field is plowed, the turning over and stirring of the soil spurs the release of carbon dioxide, which has been identified as a greenhouse gas contributing to global warming and climate change. Though industry and automobiles are responsible for the majority of carbon dioxide emissions in the U.S., the decomposition of organic matter on farmlands is a significant source of the gas. When a field is not tilled, the decomposition and resultant release of carbon dioxide is vastly slowed.
To Till or Not to Till
No-till farming has grown in popularity over the past decade, as farmers who once would have called the practice "crazy" realize the benefits in lower labor and equipment costs and increased productivity. Labor and time are saved when the farmer doesn't plow the field, and the organic matter sitting on the soil works effectively to decrease water run-off and erosion and boost the soil's nutrient retention. In 2000, about 52 million acres in the U.S. were no-till, according to the group Conservation for Agriculture's Future, for a total of about 17 percent of the country's farmland. The practice had increased dramatically between 1990 and 1995, then leveled off over the past half decade.
It wasn't until recently, however, that farmers and scientists began talking about the role of carbon sequestration (meaning 'no-till' or reduction of plowing) in connection with diminishing the greenhouse effect.
A groundbreaking $15 million project called CASMGS (Consortium for Agricultural Soils Mitigation of Greenhouse Gases) being carried out by 10 universities with funding from the U.S. Department of Agriculture is in the process of documenting the environmental benefits of carbon sequestration in agriculture and developing outreach programs to convince farmers to adopt the practice. CASMGS scientists note that while carbon sequestration doesn't actually remove carbon dioxide from the air, it can significantly slow the expected increase in emissions. If no-till farming were widely adopted in the U.S., they say the projected increase in U.S. carbon dioxide emissions could be cut by as much as 20 percent.
"Plants trap carbon during photosynthesis, and that carbon goes into the soil [in the form of plant residue] during harvesting," said Ron Turco, director of the Environmental Sciences Engineering Institute and head of the CASMGS group at Purdue University in Indiana. "We want to keep that carbon in the soil rather than releasing it into the atmosphere as carbon dioxide."
Turco noted that the original carbon content of the soil across the country has been reduced by about 50 percent since John Deere invented the steel plow in the mid-1800s. With widespread no-till, he thinks close to original levels could be restored in as little as 40 years, with 75 to 200 million metric tons of carbon sequestered per year.
"In prairie conditions, everything is in equilibrium," he said. "Then you come in with a destructive force like a plow and it causes aeration, things get disturbed. What we want to do is bring the soil back to its original quality."
There are economic and environmental drawbacks to no-till, including the fact that more pesticide is usually needed to fight the organisms that find homes in the residue. Farmers who have been using conventional plowing will also have some start-up costs to switch over to no- or partial-till equipment.
"What we don't want to do is forget all the other management concerns that have an environmental impact," said Sylvie Brouder, the Purdue scientist in charge of outreach to farmers for that region. "We need to provide guidance to farmers and look at what in the big picture is your environmental and economic benefit."
Even with the benefits, it is hard to convince farmers to change traditions and ways of doing things that have been around for generations.
"If you tilled your whole life and your father tilled before you, it's a change," said Turco. "You're used to seeing a field that looks a certain way."
Cash for Carbon
As an added bonus on top of the soil quality, labor saving and environmental benefits of no-till farming, there may soon be an added economic incentive. If the federal government passes caps on carbon dioxide emissions, as many are hoping, a market in "carbon credits" could likely develop in which those who practice carbon dioxide reduction could "sell" their credits to industries or manufacturers who fail to meet the cap. Similar markets already exist in sulfur dioxide. Many economists say that if a carbon dioxide cap were enacted, then a carbon credit market wouldn't be far behind. Then, farmers could potentially make a decent profit in credits along with their agricultural revenues.
"For farmers, their bottom line is economics," said Charles Rice, head of the CASMGS project out of Kansas State University. "If they can see an economic incentive, and improve the soil at the same time, all the better. It's taking a risk, and if there's a low profit margin than you are less willing to take that risk. That's where the carbon credit market comes in. It could help overcome that risk and fear of change."
There are several ways a carbon credit market could function. Farmers could be given subsidies or incentives from the government for adopting the practice, a measure that could be taken even if emissions caps aren't instituted. Some of the conservation funds allotted in the Farm Bill could be used for carbon sequestration incentives, a move some farmers have suggested.
A more profitable version would be the exchange of the credits on a private market, with the credits even potentially being traded on the stock market. The Chicago-based Environmental Financial Products is currently carrying out a project with funding from the Joyce Foundation and the Kellogg Graduate School of Management at Northwestern University to develop a structure that would allow the credits to be traded on the Chicago Board of Trade.
"Probably in years to come there will be a private market for carbon credits, as we learn better ways to measure and monitor it," said Bill Ryan, a farmer and former head of the Soil Conservation Service under the first President Bush. "In the short term we could have a public incentive through the Farm Bill."
Estimates of how much the credits would be worth are all over the map, depending on what type of model is developed. They range from a few dollars per untilled acre under a government subsidy program or private trading program based on voluntary emissions reductions, to $40 or more per acre if a private market based on mandatory emissions caps develops.
"If it's based on a very significant reduction required of industry, and industry can buy credits to meet that, it would be very valuable," said Catherine Kling, an Iowa State University economics professor working with the CASMGS project. "If it's based solely on voluntary reductions from companies, on 'green marketing,' then it might be a couple dollars per acre. It depends on what institutional and legal requirements are facing firms."
For carbon credit incentives to work, there would be tricky issues to address such as how to monitor whether farmers were practicing no-till and what to do if farmers sold their no-till credits but then decided they were unable or unwilling to continue the practice.
Globalizing Carbon Credits
The Kyoto Protocols, which President George W. Bush still refuses to sign, would impose mandatory caps on greenhouse gas emissions. Emissions trading programs were among the options discussed during the Kyoto talks.
Already, Canada, Norway, Australia and other countries have been experimenting with carbon credit trading. Turco noted that some Canadian companies have already paid Iowa farmers for carbon credits. He hopes that huge agricultural countries like China and India will also push the practice.
Some analysts picture that in keeping with the Kyoto Protocols a huge global emissions trading market covering all greenhouse gases will eventually develop. In this vision, manufacturers and farmers all over the world would receive payment for feeding into "an atmospheric sink" of unreleased carbon dioxide, while carbon dioxide emitters would have to pay "rent" for the right to emit the gas. In that case, a small farmer in Kansas could essentially sell his carbon sequestration credits to a pool where they might be picked up by a multinational company in Japan. A paper by the American Council on Capital Formation (ACCF)'s Center on Policy Research notes that were such a thing to develop, U.S. companies could look to buy cheaper emissions credits from abroad. That would raise all sorts of issues concerning who regulates the market and where the profit from emissions trading goes.
"The biggest obstacle to implementing such a system, should we decide to, is a crassly familiar one: who gets the rent generated by limiting the right to emit CO2," says the ACCF report.
Some environmentalists might find the whole concept of a carbon credit market dubious -- in effect, farmers using a practice that they might well have adopted anyway are helping polluting companies avoid their obligation to cut down on emissions. The concept becomes especially abstract when you consider a global market in which a U.S. corporation could continue its polluting because it is buying credits from a no-till farmer (or other emissions reducer) in China or Russia.
When it comes down to it, switching to renewable fuel sources and developing technologies for industry, automobiles and the like that have less emissions are more critical measures than no-till farming in slowing global warming.
"None of this will replace industry doing its part," said Purdue agronomy professor Eileen Kladivko. "But what we're doing is buying some time."