Farmer interest in no-till and cover crops has probably never been higher. That interest is fueled by stewardship and, in many cases, government incentives such as USDA’s Conservation Stewardship Program. Farmers are demonstrating their desire to improve soil health—and doing it in a way that’s evident to non-farmers viewing fields from highways and county roads.
Those are steps in the right direction, says Farm Journal Field Agronomist Ken Ferrie, who has been conducting soil health studies for more than a decade. However, the soil health movement prompts some concerns and questions:
1. Don’t limit the soil health toolbox. “It’s beginning to seem we can’t talk about soil health except in terms of no-till and cover crops,” Ferrie says. “This could create a problem for the ag industry in terms of public perception. There are many other tools besides no-till and cover crops to improve and maintain soil health.
“In some cases, funding is being provided to agriculture from outside sources, such as corporations, who want to do their part for the environment and ensure the products they sell are being produced sustainably. We don’t want to restrict this funding only to no-till and cover crops when there are additional tools farmers can and should use.”
2. Soil health involves numerous practices. “Maintaining and improving soil health requires balanced fertility levels; the 4Rs (right product, right rate, right time and right place); avoiding abrasive tillage; optimizing soil pH; removing and managing soil compaction; crop rotation; timely field operations; good drainage; buffer strips; grass waterways; and sometimes converting cropland to permanent pasture or enrolling it in government programs such as CRP,” Ferrie says. “Farmers use those practices because they are good for yield and profit as well as for the soil.”
3. The wrong message might create confusion. “Because the message farmers hear so often is ‘no-till plus cover crops equals healthy soil,’ some who have adopted no-till because it’s profitable ask me about adding cover crops,” Ferrie says. “They say their goal is to improve soil health, but they forget they’re already doing that with other practices. Going from no-till to no-till with covers while maintaining the same level of profit is difficult.
“To be widely adopted, cover crops must either reduce cost, increase yield or both. Some growers who own their land and are good stewards are willing to sacrifice some profit for a while to improve their soil. But many farmers who cash rent and deal with absentee landowners who don’t understand or care about soil stewardship can’t give up profit and remain sustainable.”
4. Farms must be economically sustainable. “Throughout history, there have been situations where farmers eventually destroyed their soil through unsustainable practices, and areas once breadbaskets turned into wasteland,” Ferrie says. “We must avoid that—and farmers want to avoid it. They know their land is their family’s future.
“But farmers must make a profit or they won’t be around to take care of their soil. When a farm is not profitable, the operator worries about survival more than about stewardship.”
In the rush to incentivize soil health practices, Ferrie fears this message might be getting lost. Much research is needed to prove soil health practices are profitable or how to make them so, he suggests.
“For the masses of farmers to adopt something, there must be a profit,” Ferrie says. “If a suite of practices improves soil health and the environment and has zero cost, farmers will implement those practices because it’s the right and sustainable thing to do. They won’t need the incentive of government subsidies to adopt them.”
5. One size doesn’t fit all. “Some of my most profitable clients are no-tillers—but so are some of my least profitable clients,” Ferrie says. “How well no-till works depends on a farmer’s ground, crop rotation and level of expertise.
“For those who haven’t yet figured out how to make no-till profitable in their situation or environment, there are other practices they can use to improve and maintain soil health. In our enthusiasm for no-till, we must not forget about these other practices.”
In some situations, no-till and cover crops are almost certain to be profitable, Ferrie says. “They can be used following silage harvest, to grow a crop to prevent erosion, to be harvested or to be grazed,” he says. “They can be used to prevent soil on sand hills from blowing.
“The biggest benefit of no-till and cover crops is to reduce soil erosion,” Ferrie continues. “Neither farmers nor the public want soil to enter streams. But even in regard to erosion control, we have other tools, such as various forms of reduced tillage, contour farming, buffer strips and grass waterways, and we should use all of them.”
6. Allow time for the learning curve. “New practices should be adopted over time,” Ferrie says. “Try them on a small scale, learn about them, adapt them to your specific conditions and eventually, over time, proceed in a new direction.
“This is especially important with no-till. If you don’t prepare a field by balancing fertility and correcting pH, which might initially require incorporating fertilizer and lime, and removing compacted layers, you won’t realize the full benefits of no-till. You might also need to improve drainage. Draining wet ground makes the soil come alive and causes health indicators to move in the right direction.”
It’s similar with cover crops. Plant replicated strips of various covers across a field. Conduct soil health tests and measure the changes in your soil. Learn to manage cover crops, and determine their true cost and benefit. See if the improvements in soil health translate into increased yield and profit.
“In our trials so far, we have found that difficult to do,” Ferrie says.
He also recommends making your comparisons in the same field, rather than in two fields several miles apart, where yield differences might be due to rainfall and planting date. Consider all costs, he says, including the actual cost of tillage and seeding the cover. “If you eliminate a residual herbicide because of the cover crop, that’s not necessarily a savings if you have to make one or more rescue treatments for late weed outbreaks,” he explains.
7. Tillage isn’t necessarily harmful to soil health. “Over-emphasizing no-till might create the impression all tillage is detrimental to soil health,” Ferrie says. “Too much tillage at the wrong time can destroy soil. But I’ve seen a number of instances where farmers using tillage had higher soil health test scores than their no-till neighbors (and vice versa, of course).
“The effect of tillage on soil health depends on how a farmer does it and what practices he uses. If a farmer uses conservation tillage that leaves enough residue cover to protect the soil, balances fertility and maintains optimum soil pH, he’ll have healthier soil than a no-till farmer who fails to do those things.
“Our goal is to have a system that is economically, agronomically and environmentally sound,” Ferrie summarizes. “No-till and cover crops are important soil health tools. But I worry about conveying the impression that if you don’t no-till and grow cover crops, you’re a bad steward of your soil. Soil health is much more complex than that.”
A Soil Health Dilemma Rears Its Head
Farm Journal Field Agronomist Ken Ferrie spends a lot of time thinking about soil health. This question has him concerned: Does improved soil health translate into improved water quality?
“So far, the answer is not always,” Ferrie says.
Nutrients reach water two ways: in sediment carried by surface runoff and as dissolved nutrients in surface runoff and subsurface water. “Reduced tillage and cover crops, if done right, can definitely reduce sediment loading,” Ferrie says.
Dissolved nutrients are another matter. Nitrate is a source of concern in drinking water, and the combination of nitrate and phosphorus causes algae blooms in water bodies. When algae decomposes, it uses up the oxygen in the water, making it unlivable for some aquatic creatures.
“The dilemma that’s coming to light is healthy soil releases more nutrients into the soil solution,” Ferrie says. “That’s good for plant growth, but nitrate and dissolved (ortho) phosphorus are highly leachable. In our studies, it has been more difficult to keep nitrate and dissolved phosphorus out of surface runoff and tile water under no-till and no-till with cover crops than under tilled soil.”
The first two years of a four-year study at Kansas State University echoed Ferrie’s observations that no-till with a cover crop increased the loss of dissolved phosphorus versus no-till without a cover.
Dissolved phosphorus is a bigger threat to water than particulate phosphorus, which is attached to soil particles and can be controlled by reducing soil erosion. Dissolved phosphorus is much more bioreactive (80% to 90%) than particulate phosphorus (30% to 35%).
“There also are indications nitrate and dissolved phosphorus are stronger in surface runoff under no-till and cover crops because of the decomposing residue,” Ferrie says.
“While cover crops can pick up nutrients, reducing their loss through drainage water, at some point that residue decomposes. Decomposition releases nutrients at the soil surface, where they can be carried off in runoff water,” he adds.
Protecting water quality seems to depend more on balanced fertility and the 4Rs (right product, right time, right time and right placement) than on no-till or cover crops, Ferrie says. “As we strive to improve soil health, we must look at all these practices, as well as edge-of-field practices such as tile gates and bioreactors,” he encourages. “It would be a mistake to promote only a couple soil health practices, which might fail to improve water quality.”