At a glance, no-till farming appears to be a silver bullet. Researchers and a small subset of Washington’s farmers claim it reduces greenhouse gases, produces higher crop yields and improves the health of local fauna, all while reducing costs to the farmer.
However, several recent studies from around the globe tell a different story. No-till’s carbon dioxide savings may be outweighed by an increase in nitrous oxide produced by the farming practice.
Traditional agriculture accounts for 80 percent of nitrous oxide and 30 percent of methane emissions in the US, according to a presentation from David Granatstein, a researcher with the WSU’s Center for Sustaining Agriculture & Natural Resources (CSANR) and the USDA.
A further increase in emissions from widespread no-till techniques could add to nitrous oxide’s impact on the environment, which already accounts for six percent of the earth’s greenhouse effect, and has 298 times more warming potential per molecule than carbon dioxide, according to Granatstein’s presentation.
But an overall increase in greenhouse gas (GHG) emissions due to nitrous oxide has yet to be definitively pinned down.
A 2010 study released in ‘Soil and Tillage Research’ measured fluxes of nitrous oxide, carbon dioxide and methane on conventional farmland and land that has been no-till for 5-7 years in Northern European climates.
The results suggest there is a risk of increased nitrous oxide emissions in the first years of no-till, while carbon dioxide is reduced and methane fluctuation is negligible.
A separate study conducted by the School of Environmental and Natural Resources at Ohio State University in 2008 says otherwise.
“Data from this study suggested that adoption under no-till ... may reduce Global Warming Potential associated with nitrous oxide and methane emissions by approximately 50 percent compared to (conventional tilling techniques),” the study said.
The verdict on nitrous oxide has not been finalized, with the environmental risks and rewards dependent just as much on tilling techniques as the location of the land.
“We’ve done some studies on it at WSU and I’d say the jury is out, it’s not entirely clear,” Granatstein said. “We ran some work with the crop model and did some field measurements, what we found was that carbon was going down but that nitrous oxide was indeed going up.”
Granatstein also mentioned that results for different parcels of land short distances apart produced different results, further confounding the results of their studies.
“In short, there’s no forlorn conclusion.” Granatstein said. “In some cases it goes one way and in some cases it goes another.”
No till on the Palouse
John Aeschliman is in a unique position to assess no-till farming’s impact in the area; he has been doing it longer than anybody else.
For more than 35 years Aeschliman has run a no-till system on his land near Colfax, Wash.
“I was fortunate enough to get to rub shoulders with some of the early no-till innovators way back in the 1970s,” he said. “In fact I had one of the first no-till drills that was built in the Palouse.”
For Aeschliman, the gain or loss of greenhouse gases is of lesser consequence. The real reward for no-till on the Palouse is soil conservation through reduced erosion.
“There’s hardly any place else in the US or the world that’s like the Palouse,” Aeschliman said. “In fact the Palouse soil is some of the richest in the world.”
Despite the rich soil, Aeschilman said Palouse area farmers face a distinct problem.
“The main challenge is that it’s very hilly and steep,” he said. “And that was the main reason I went into it in the first place was to control the erosion.”
In a conventional tilling system, nutrients and fertile topsoil would get washed further downhill with each tilling cycle. The no-till system keeps the soil and nutrients in place, creating and saving the fertile soil.
Aeschliman said he hasn’t heard any definitive evidence about an increase in nitrous oxide from no-till farming.
“I’m not just sure what direction (the researchers) are coming from on that,” he said. “Both conventional and no-till (farming) use commercial fertilizers that put down the nitrogen.”
According to Aeschliman, no-till and conventional systems fertilize basically the same, and the only increase in atmospheric nitrous oxide would come from a no-till system being agitated.
“I don’t want to say they’re not true,” he said. “But I’m not aware of (an increase in nitrous oxide) as a fact.”
Research on no-till
“No till farming is exactly what it sounds like,” said Chad Kruger, the director of WSU’s Center for Sustaining Agriculture & Natural Resources (CSANR). “You plant the new crop without tilling the soil after you harvest the last crop.”
Kruger has headed the CSNAR for the last seven years, including directing an award-winning program that focuses on evaluating the carbon footprint of agriculture.
“Probably the number one facet (of no-till) is reduced erosion potential, either wind-based erosion or water-based erosion,” he said. “Because you haven’t disturbed the soil with tillage and exposed it to the elements, the residues from the prior crop stay on top and hold (the soil) together like a natural prairie.”
With soils more firmly in place, the ground becomes increasingly fertile through more permanent carbon sequestration, he said. This carbon capture inhibits the release of CO2 into the atmosphere.
No-till’s more established root system can decrease the amount of contamination from farming that runs into water systems, trapping and filtering field runoff, Granatstein said.
“Of course soil erosion by itself is a problem in the field but then it has all kinds of problems when that soil washes into water and goes off-site,” Granatstein said. “So the problem is a lot bigger than a farmer just losing soil, and (no-till) does a lot more than just help the farmer keep his soil.”
Promising, but with further flaws
Although the battle over no-till’s role in GHG emissions is not over, no-till doesn’t come without its own concrete drawbacks, Kruger said.
“The big environmental concern with no-till is that it’s dependent on herbicides,” he said. “In a conventional system we use tillage to control weeds, but if we reduce tillage, we lose our ability to easily control weeds.”
Without the physical ability to efficiently remove weeds, farmers must rely on chemicals like Roundup, which have their own environmental shortfalls, Kruger said.
“Generally speaking though, the environmental benefits outweigh the herbicide issue,” he said.
However, Kruger said the herbicide tradeoff depends largely on your perspective.
“There’s lots of people out there that think that the negatives that come with the herbicide use outweigh the greenhouse gases saved and erosion,” he said. “It just all depends on your situation.”
No-till crops may also be more susceptible to disease if not rotated properly, Kruger said, and knowledge about how to care for a no-till system is not as readily available as traditional agricultural means.
But ultimately, the no-till system boils down to dollars and cents. Most farmers won’t transition to a no-till system if it won’t earn them more money, he said.
“Buying a no-till drill and a no-till sprayer and all of the other equipment necessary to run that type of system is fairly expensive when you add it all up,” Kruger said. “It doesn’t make a lot of sense to switch systems if you’re not convinced it will make you more money and you’ve been farming a certain way with success for a long time.”
There is also a transitional period when switching to the no-till system where farmers may experience poor yields and a lack of know how, he said.
When combined with drainage issues in wet climates and hydration problems in dry ones, no-till can be a tough sell.
“Switching over can be a huge challenge,” Kruger said. “And it scares a lot of farmers away.”
Though the cost of new equipment is a drawback, Granatstein said it is minor when state grants and reimbursement programs that encourage no-till farming are considered.
The main problem is mentality, he said. Though research has ironed out most of no-till’s problems, it hasn’t flattened them all. That mindset sticks with most farmers who see no incentive to rock the proverbial boat.
“No till wasn’t all that successful in the beginning like it is now, and it has taken a while for people to get over that,” Granatstein said. “Farming is a pretty high stakes business and people would rather stick with what they have than try something new and risk it all.”
If not a silver bullet, at least a silver lining.
Though no-till has its drawbacks, the consensus from farmers and scientists in the region remains positive: the benefits of no-till outweigh the risks.
“Not all of the different no-till systems are equally good for the environment, some are better than others,” Aeschliman said. “But they’re all better than till systems.”
No-till also increases the amount of healthy bacteria and macrophages that may be missing from tilled soil, Kruger said. In turn, the stability brought on by no-till methods creates a more rich and stable living environment for animals like earth worms to thrive in.
“It’s not a perfect system yet, but it’s getting better all the time,” Granatstein said. “And it’s very exciting.”
