I wrote about organic no-till farming for The Christian Science Monitor recently. To read the article, follow this link.
Below is what you might call the "director's cut" of the article — longer, a different lead, and some more in-depth information I learned during my reporting that there wasn't room to include in the print version. I thought I'd post it in case someone reads the Monitor article and wants to know a little more.
ORGANIC NO-TILL FARMING
by Jared Flesher
Professor Bill Curran of Pennsylvania State University describes organic no-till farming as "the nirvana of agriculture."
And Jeff Moyer, farm director at the non-profit Rodale Institute in Kutztown, Pa., is the man trying to achieve it.
Organic no-till is an experiment that combines two agricultural practices — organic farming and no-till farming — that are seemingly contradictory. Organic farmers don't use herbicides, so they control weeds by tilling (plowing) their fields frequently. Conventional no-till farmers don't plow, so they rely heavily on herbicides for weed control.
Something the practices have in common, however, is that each has environmental benefits. In addition to preventing soil erosion, no-till farming has been eyed as a solution to global warming because less plowing means less carbon will escape into the atmosphere each time the ground is disturbed. Similarly, in addition to the benefits organic farms confer by eliminating chemical pesticides and fertilizers, they also build up more organic matter in the soil, which in turn increases the amount of carbon the cropland can store.
Rodale Institute researchers crunched the numbers and calculated that if they could manage to combine the carbon sequestration potential of no-till with the best practices of organic farming — including cover crops, crop rotation and composting — each acre of farmland could sequester 3,000 pounds of carbon per year or more, ten times the amount they say is typically achieved with conventional no-till alone.
The claim: If organic no-till agriculture was used successfully on each of the earth's 3.5 billion tillable acres, it would sequester more than half of all present day CO2 emissions, according to Rodale Institute research director Paul Hepperly.
But is organic no-till farming even possible? The answer so far is yes — but only sometimes. It's a work in progress.
The Rodale Institute was founded in 1947 and has been a leader in promoting sustainable agriculture ever since. Its Farming Systems Trial for corn, wheat, and soybean production began in 1981 and is the longest-running side-by-side comparison of organic and conventional farming in the country.
Mr. Moyer says his quest for organic no-till began as a fortuitous accident 18 years ago. As part of an experiment, researchers planted a field with a cover crop called hairy vetch and divided it into observational plots. The end of the field wasn't part of the experiment, however, so to get to the plots they drove over that end with tractors, crushing down the vetch. But later, after the field was planted with corn, Mr. Moyer noticed something interesting was beginning to happen where the tractors had trampled everything.
"It looked like a mat of cardboard with this dead mulch with our corn plants coming out it," he said. "And everybody stood there and looked at it and went, 'Wow, you did organic no-till.' So we've spent the last 18 years trying to figure out a system that will allow us to replicate that accident over and over and over again."
Mr. Curran, a weed scientist in the Department of Crop and Soil Sciences at Penn State, has studied organic no-till while conducting research funded by the USDA. It's such an attractive model of farming, he says, because it preserves the greatest benefits of the two systems it marries while minimizing their drawbacks.
"In this day and age of energy and global climate change, not having to rely on fossil fuel-based inputs is really a key to long-term sustainability," he said. "And the biggest problem with a lot of organic systems is that they're very dependent on plowing the soil. So if you can combine the philosophy of relying only on organic inputs, along with less tillage and less soil disturbance, I look at that as sort of the ideal situation."
One of the biggest challenges organic farmers face is weed control, and so the paradigm shift represented by organic no-till is that it strives to do the job without the two most potent weapons in the anti-weed arsenal. In place of herbicides or tillage, cover crops become the key weed control strategy. They are planted between rotations of food crops and serve the dual purpose of replenishing nutrients in the soil while keeping the ground covered and weed-free. But since organic no-till farmers don't plow the cover crop under at planting time, they must knock it down in precisely the right way so they can plant through it.
To that end, Mr. Moyer experimented for 11 years with modified versions of existing farm equipment — cultipackers, flail mowers, and rolling stalk choppers — but only achieved modest results. By 2002 he knew he needed some sort of mechanical roller that rides out in front of a tractor to crush the stem of the cover crop without, crucially, actually cutting it. This would allow a seeder or grain drill behind the tractor to glide through without getting clogged up.
This piece of equipment didn’t exist, so Mr. Moyer designed it himself and had one built at a neighbor's weld shop. Called a "roller-crimper," the prototype worked better and now, seven years later, they are being built and sold commercially by an independent manufacturer. Dozens of them are being used across the country by agricultural researchers and early adopter farmers.
Bill Mason, a corn, soybean, and grain farmer on Maryland's Eastern Shore, is one of those early adopters. His reason for the switch had nothing to do with carbon sequestration and everything to do with another promise of organic no-till — it can help farmers make more money. Organic crops sell for more than conventionally raised crops, while no-till cuts down on tractor use, reducing a farmer's fuel and labor costs.
In 2005, Mr. Mason decided to transition a significant portion of his 600 acres from conventional to organic production after he determined he couldn't stay in business if he didn't make more profits off the land he had. After his first season of plowing and cultivating with organic, however, he was somewhat dismayed with all the extra time and fuel he was expending to keep his fields in shape.
"I was just thinking, you know, it's a lot of fieldwork compared to the methods we had used previously," he said.
Mr. Mason had heard about the experiments the Rodale Institute was conducting with organic no-till, so he consulted with Mr. Moyer, purchased a 15-foot roller-crimper for $4,000, and decided to give it a try with a field of soybeans. He knew he was taking a gamble.
"When you go out and roll a 120-acre field down and pray that it's going to work, it's a good portion of your income," he said. "You're taking a little bit of risk there."
Mr. Mason said his results that first year were "excellent." His organic soybean yield was as good as his best conventional yields, and he was able to reduce his trips across the field in a tractor from eight passes to just one. He figures he is saving about $50 per acre in fuel and machinery costs alone, not counting the labor savings. He has now been using organic no-till for three years, and he says he would recommend it to anybody, at least for soybeans.
Corn, though, has been a different story. His results so far with this crop have been disappointing, plagued by insects and poor yields. Across the country, USDA-sponsored research into organic no-till has been conducted in Georgia, Iowa, Michigan, Mississippi, North Dakota, and California. Experimenting with the different variables of climate, soil, and crop variety, researchers have reported results ranging from excellent to abject failure.
Also, it turns out "organic no-till" is still something of a misnomer. The Rodale Institute and other practitioners have found it's only possible to no-till a field a few years in a row before more aggressive perennial weeds start to gain a foothold. Mr. Mason has been tilling his soybean fields every other year to control weeds, while Mr. Moyer has been tilling two or three times every five years at the Rodale farm. Still, that represents a reduction in tillage of 40 to 60 percent.
"We're making progress," says Mr. Curran. "We still need to work some of the bugs out."
Using the Soil to Sequester Carbon
Mr. Moyer calls carbon sequestration "a glorious byproduct" of organic farming.
In 2003, the Rodale Institute made news when it released research results from its Farming Systems Trial that showed its organic cropland was sequestering 1,000 pounds of carbon per acre per year, a number so high that it was received at the time with skepticism by a number of other soil researchers. Mr. Moyer says more research since then has corroborated what the Rodale Institute has claimed all along – that organic farming, even with tillage, can actually store more carbon than conventional no-till farming.
Agricultural practices that promote carbon sequestration can be "stacked," Mr. Moyer says, so the idea is that combining them together in one farming system will foster the best results. The Rodale Institute initiated organic no-till into the Farming Systems Trial just last year, so it will be about five years before they have the hard scientific data to back up (or not) the even higher sequestration results they project. They expect that stacking no-till with organic will sequester at least 1,500 to 2,000 pounds of carbon per acre. Add in still another farming practice that builds soil, composting, and that number may rise to 3,000 pounds or more.
Rattan Lal, professor of soil science at Ohio State University and director of its Carbon Management and Sequestration Center, has done much of the pioneering research into carbon sequestration. His latest data shows that conventional no-till with residue mulch can store 500 pounds of carbon per acre; conventional no-till with a winter cover crop can store 1,000 pounds; and conventional no-till with a cover crop plus manure added can store 1,500 pounds.
In other words, yes, stacking appears to work.
"No-till organic is probably one of the best systems for helping to sequester carbon," says John Reganold a soil scientist who has studied sustainable agriculture at Washington State University for 25 years. "What Rodale is doing is the best of both worlds."
There are, to be sure, still significant uncertainties surrounding organic agriculture in general and soil carbon sequestration in particular.
One long-running debate is whether organic agriculture can produce enough food to feed the world. Critics say that because organic farms yield less food per acre than conventional farms, a large-scale shift to organic would lead to starvation or more deforestation for cropland. The organic response has been that organic farming will actually help feed more people, because it improves the sub-optimal yields often found in the developing world.
For Rodale's part, their trials have found organic yields to be within 5 percent of conventional yields most years, while outperforming the conventional system in years of extreme weather patterns such as drought.
Other research casts doubt on the existing science of how much carbon no-till farming actually saves claiming that the soil in many studies was not sampled deep enough to get reliable results. A recent study by Lal found that the effectiveness of no-till in terms of carbon sequestration is largely dependent on soil type and conditions, and in some cases it's not helpful.
Lee Burras, a soil scientist at Iowa State University, does believe agriculture can help in the fight against global warming, but he's tempered in his view of how large a role it can play. He estimates the amount of present day carbon emissions that could be sequestered by soil to be about 10 percent.
"Can it help mitigate? Yes," he said. "Is it the long-term, major solution? No."
Part of the reason organic and no-till farming are only temporary solutions, he says, is because the ability of soil to sponge up more and more carbon will eventually run out.
"My own work shows the more beat up [the soil] is to begin with, the better response you get subsequently with carbon sequestration," he said. "But after 10 years, 20 years, maybe it's 50 years, we're going to plateau out, we're not going to see more gains."
Another looming question in this debate is how to get conventional farmers to embrace alternative farming methods.
"Farmers are very conservative people by nature," Mr. Moyer admits. "When you ask a farmer to adopt a new technology, they are literally risking the farm, their home, and their income, on this new technology."
The allure of reduced fuel costs and better prices for organic produce might not be enough. Mr. Hepperly, the Rodale Institute research director, says that for a significant switchover to occur in this country, the U.S. government must enact a system that pays farmers to sequester carbon. Carbon trading like this is already being experimented with at the Chicago Climate Exchange and elsewhere. The Rodale Institute is advocating that such a trading system be enacted in the next farm bill in 2012.
"This will allow farmers to see a real economic motivation to resolving these core issues," Mr. Hepperly said.
Mr. Burras agrees.
"I strongly support the idea of green payments," he said. "Any practice that results in better carbon sequestration results in better environmental quality across the board."