Dilemma 1: Establishing a Baseline
Dilemma 2: What Impacts Soil?
Living Roots
Integrate Livestock
Understand Your Context
Improved soil health is a key element of gaining regenerative farming certification, a standard many of the largest retailers in the U.S. are demanding from their food producers. But that creates a dilemma on two fronts.
First, how do you establish a baseline when soil types and content vary within a single field, much less over an entire operation? A second problem? If you multiply the depth of the topsoil by an acre, the volume will be enormous. Using additives alone to improve soil health is cost prohibitive. What actually has an impact?
We spoke with experts from two groups, Regenified, a certifying company for regenerative farming, and Noble Research Institute, a nonprofit focused on educating farmers and ranchers on soil health and profitability.
The first step to measuring improvement in a system is, of course, establishing an initial baseline from which to make comparisons. Setting a soil health baseline can be straightforward, even if farms’ climates vary wildly. The goal is to get a picture of where a farm begins its journey so future testing can see how its soil health progresses over time, says Doug Peterson, Director of Standards & Protocol at Regenified.
“We do a variety of soil testing, a variety of field evaluations,” Peterson says.
The list of soil characteristics Regenified evaluates is based on the six principles of soil health:
Minimize disturbance
Keep soil covered
Maximize diversity
Maintain living roots
Integrate livestock
Understand your context
USDA lists only the first five principles. But those engaging closely with working farms quickly realized growers face unique challenges. Integrating livestock into lettuce production, for example, would violate food safety regulations. So Regenified, Noble, and other similar organizations added the sixth criterion.
These six principles can work with any type of agriculture, say both Peterson and Jim Johnson, Product Delivery Manager at Noble Research Institute, whether it’s vegetables, orchards, vineyards, grass, or commodity crops.
“Integrate those principles as much as possible. And then, as you do that, you begin to see what’s going on and integrate them more,” Peterson says.
So how does Peterson set a baseline? First, each farm will have its own baseline and will not compare with other farms, he says. A farm on clay with 40 inches of rain, for example, will have little in common with a farm in an arid region with sandy soil.
Even if farms have different types of soil in one field, they likely still have enough similar characteristics or a crop wouldn’t be put in that field. The different soils in a single field will not differ as much as a humid, sandy Florida field does from a field in Michigan.
“We'll sample a transect. We'll go across the rows perpendicularly, so that we get an equal representation of the rows. The inter-row area all the way across a field,” Peterson says.
As for what’s measured, Peterson says they evaluate how each farm is living up to the six principles along with soil tests.
“The aggregate stability is kind of like the canary in the mine. If we have good aggregate stability, that means we’ve got … living roots in the soil. It most likely means we have good ground cover.”
Doug Peterson, Director of Standards & Protocol at Regenified
One test he favors is the Haney test.
“A lot of historical soil tests were done based on harsh acids,” Peterson says. “Dr. Haney developed this test that looked at what nutrients were going to be made available to plants by biology.”
There are several tests Regenified has in its toolbox, some looking at fatty acids, some looking at the bacteria to fungi ratio, and protozoa levels.
But Peterson says there’s one test he’d pick over all others if forced to choose just one: an aggregate stability test.
“The aggregate stability is kind of like the canary in the mine. If we have good aggregate stability, that means we’ve got … living roots in the soil. It most likely means we have good ground cover,” Peterson says.
Overall, Regenified looks at 65 different data points, although all 65 may not be applied to every land use.
The volume of soil in a single acre measures roughly 2 million pounds. Obviously, amendments can act only as assistants and not the main players in improving soil health.
That’s where the six principles of soil health come in, Noble Research Institute’s Johnson says.
“We always start with the soil-health principles and the ecosystem processes,” he says.
As Peterson and Johnson describe the different principles, keep in mind that there is no perfect end goal.
“We talk about direction over perfection,” Johnson says. “Take the small steps you can.”
1. Minimize Disturbance
When farmers hear the term “minimize disturbance,” tilling comes to mind.
While that is a form of disturbance — and cutting tillage where we can matters — Johnson says, inputs like synthetic fertilizers and pesticides are another.
“It's more about the disturbance it could do to the ecosystem,” Johnson says. “When we apply a synthetic fertilizer, we short-circuit the natural production of nutrients from that ecosystem.”
Plants will be as energy efficient as possible. If they have an available synthetic source there so that they don’t have to trade any sugar with fungi or bacteria to get the same nutrient, they will do that, Johnson says.
Doing so bypasses the natural sources in the soil and disrupts the cycles that give soil life.
As for pesticides, they may kill beyond their target pest.
“We may inflict unintended consequences on some of that biology in the soil that is really hard to see,” Johnson says.
Plants will be as energy efficient as possible. If they have an available synthetic source there so that they don’t have to trade any sugar with fungi or bacteria to get the same nutrient, they will do that.
Jim Johnson, Product Delivery Manager at Noble Research Institute
2. Covering Soil
Soil cycles nutrients to a plant, Peterson says, and bare soil leaves that system open to damage.
“We have to realize that it is an ecosystem, a habitat for soil biology,” Peterson says.
And it’s so important, Peterson says soil should be covered 365 days a year, “no matter what’s going on.”
The crop itself, a cover crop, or plant residue from the previous crop is ideal cover.
Mulch is another option, Johnson says.
“[It’s] ideally an organic mulch of some kind, but even a synthetic mulch of some sort protects the soil.”
3. Plant Diversity
There are four basic plant types, Peterson says: cool, warm, grass, and broadleaf.
“Most of the research shows that if farms have about three out of the four of those plant types, that's where you end up with the most efficient nutrient cycle, the best biological community,” Peterson says.
Johnson says diversity applies to more than plants. It applies to invertebrates, animals, pollinators… “All the diversity.”
A commercial farm will often have just one crop in a field at a time. How can a grower build diversity in that scenario?
“If you are growing 10 different crops, grow them in a different location around the farm year over year,” Johnson says.
He has seen growers succeed with adding crops between the rows.
For example, a Colorado potato grower Johnson knows uses companion plants — three to seven other species at a time. Some are flowering plants attracting beneficials, which is part of the grower’s IPM program.
Johnson says he’s seen growers use plants like buckwheat and flax and non-flowering plants effectively as well. He’s also seen where growers interspersed a mix of these types of plants within a row. They can run every 100 feet or maybe every 100 yards, he says.
Others use the border of the field for that purpose.
“It's also building the soil at the same time,” Johnson says. “That grower has some of the best soil that I've seen anywhere because of following the soil principles, having diversity and minimizing tillage where he can.
And never overlook a good rotation plan. In a given field, the Colorado potato grower will follow a potato crop with two years of cover crops, then perhaps hay or quinoa before rotating back to potatoes.
When Peterson assesses a farm, he’s looking at how much of the year it has living roots in the soil. That can be in the form of a cash crop or a cover crop.
There’s a rich trove of research available to growers about the best cover crops for them. They can range from plants that help battle diseases to those that add nutrients to the soil.
But even crops that act as a cash crop, like alfalfa, will help, Johnson says. Since growers tend to keep alfalfa in place for anywhere from two to seven years, that keeps a living root in place all that time.
“Even if that root is not super active in the winter, somewhat dormant, it's still a live root in the soil,” Johnson says.
Perhaps the most problematic soil principle for produce growers is to integrate livestock.
“We absolutely believe that that adding livestock is a tremendous opportunity,” Peterson says. “But having said that, we also realize that there are some situations where from a legal standpoint, they can't.” Any situation where integrating livestock would go against any type of state, federal, or local regulation wouldn't be required.
For vegetable crops, livestock would enter the field during the cover crop years or immediately after a harvest.
“It gives farmers an opportunity to turn a cover crop into a potentially a profit center as opposed to just something that's needed the rest of the year to provide ground cover,” Peterson says.
In orchards, livestock can roam alongside the developing crop. Many almond orchards use sheep to clear mummies from the ground. It also reduces the need for mowing.
So, are some types of livestock better than others for cropping systems?
As always, it depends on where you’re located and what you grow, Johnson says.
“Cattle are going to be one of the most difficult because they’re big,” he says. “They take up more space. They need more water to drink. It’s a lot bigger job to move them.”
Sheep, goats, and chickens are easier to move, he says. Some growers have worked well with hogs, Johnson says.
“If hogs went in after harvest, they could forage and feed on the aftermath, leftover crop and plant residue if it's a crop that's going to be tilled at some point in time. You're going to work everything back down,” he says.
Peterson says Regenified is working to educate regulators.
“In some cases, we are working with regulatory bodies to try to help them understand what it means to integrate livestock into those systems. It's absolutely a way to make those systems healthier and more productive to make the plants grown in the rest of the rotation more nutrient dense than without,” Peterson says.
All of the above principles have barriers for adoption, especially for high-intensity production systems like vegetables. Making each principle work within a grower’s situation is the critical factor.
“We realize there are crops that may require a clean seed bed,” Peterson adds. “Although there’s a lot of things that can get planted into residue that historically have been planted in clean tilled seed bed.”
Context is always key.
Johnson points out that the context for a vegetable grower rotating through three crops in a field during a single year differs from that of a corn and soybean grower in Ohio or a livestock producer in Oklahoma. “Context includes everything, from your financial capabilities to your labor capabilities to your knowledge capabilities,” he says.
