Regenerative agriculture, permaculture and soil health have come to the forefront of gardening conversations in recent years, but for the layperson, useful definitions for these terms can be elusive. Fortunately, to explain this soil and agriculture terminology in an approachable way, my guest this week is Dr. Jake Mowrer, an expert on all things soil.
Jake is “Mr. Soil Science” in my book. He excels at taking a topic that often confuses people and breaking it down into something that’s easier to understand. Jake earned a Ph.D. in soil fertility and soil chemistry from the University of Georgia. Today, he is an associate professor and extension specialist at the Texas A&M University Department of Soil and Crop Sciences, where he specializes in soil fertility and water resource management.
Soil science is going to play a very large role in finding solutions to some of the world’s biggest challenges, Jake says, including climate change, hunger, water security, energy security, endangered species protection and a host of other environmental declines.
Organic gardening and regenerative agriculture concepts have a lot of overlap, but regenerative agriculture calls for a more aggressive approach, especially toward addressing climate change and social responsibility, Jake says.
Agriculture Terms That Raise Questions
For his duties as an extension specialist, Jake takes many calls from both farmers and homeowners, and he works with Master Gardener and Master Naturalist programs as well. He’s often asked “What is soil health?” and “What is regenerative agriculture?” and “What is permaculture?” (More on these terms below.) He’s happy to explain it to those who are unfamiliar. For those with some idea, he explains how they can apply regenerative and permaculture methods to their farms or gardens.
Jake encourages anyone who stewards lands to make a checklist of their dreams, goals and expectations for that land, and to outline a path that aligns with principles of permaculture while also taking them to their destination. The goals could be to feed one family while enhancing biodiversity or to build an agri-tourism business. Anyone, from a gardener with a 600-square-foot garden to a farmer with hundreds of acres, can adopt these principles.
Of course, everyone’s soil and property are different, and there’s no rule of thumb or one-size-fits-all solution. “So we have to become the best scientist on our property that we can be as the owner, the manager, the person responsible for that soil,” Jake says.
Jake points to a famous saying about the underappreciated importance of soil: “Man, despite his artistic pretensions and many accomplishments, owes his very existence to a thin layer of soil and to the fact that every so often it rains.”
President Franklin D. Roosevelt delivered another famous soil quote that Jake likes: “The nation that destroys its soil destroys itself.”
President Roosevelt wrote that statement in a letter to governors about the Dust Bowl, which peaked in 1933 in American and Canadian prairies. The wind had blown soil from the Midwest to the steps of the U.S. Capitol in Washington, D.C. Back then, it was clear something had to change to stop soil erosion. More recently, there is a greater understanding that more needs to be done to maintain and improve soil’s long-term sustainable production.
Understanding and Improving Soil Health
To understand the term “soil health,” it helps to understand a few other soil terms first.
Soil is formed in layers, also known as soil horizons, that were laid down on the surface or grew from the bottom up, Jake says. The particles in soil (sand, silt, clay) form aggregates when they bind with organic matter, and that is what creates soil structure. The smallest particles in soil (the clay are known as the colloidal fraction, and they are really important because that’s where soil is its most chemically active, Jake explains.
“Tilth” is a word that refers to the physical condition of soil and its suitability for crop production. “Soils with good tilth are going to facilitate seed germination, and they’re going to promote a lot of root exploration in the soil,” Jake says. Good tilth also means soil has adequate pore volume — the void between soil particles where air and water can flow — and adequate organic matter and drainage.
And then there is “soil quality,” a term formerly favored by the U.S. Department of Agriculture’s Natural Resources Conservation Service. Soil quality refers to the inherent characteristics of soil: organic matter content, salinity, tilth, compaction, available nutrients, and rooting depth.
The Natural Resources Conservation Service, around 2010, began to favor a new term, “soil health,” which is defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. Jake says the updated terminology takes into account the services that soil provides, such as regulating water, filtering pollutants and cycling nutrients.
To sustain soil health, there are a number of recommendations, starting with armoring the soil. That means using a cover crop or mulch to prevent erosion. Uncovered soil can wash away in the rain or dry out in the sun and blow away as dust. Rain also hits soil with the force of a hammer striking a nail, which can cause the soil surface to become compact and impenetrable.
Further recommended practices include building up the organic matter — by adding compost, turning in cover crops and using organic mulch — and avoiding soil disturbance, which means ditching the tiller.
Understanding and Implementing Regenerative Agriculture
“Regenerative agriculture” describes farming and grazing practices that reverse climate change by rebuilding organic matter and restoring degraded soil biodiversity.
“Regenerative ag is based on the idea that loss of soil, fertility and biodiversity poses a mortal threat to mankind,” Jake says.
The recommended practices for regenerative agriculture boil down to “do no harm,” but Jake says many of the instructions are quite vague: improve the land, revitalize the soil, “be dynamic and holistic.” However, other recommendations are more clear: reduce tillage, use cover crops, practice crop rotation, and apply compost.
Tillage is the mechanical process of dragging an implement through the soil, disturbing it. There are many different types of implements, some that disturb the soil more than others. There’s the strip-tiller and chisel plow, which do less disturbance, and then there’s the moldboard plow, which destroys the top horizon and mixes it with the horizon below.
Minimal tillage will allow for seed-soil contact, less compaction and better drainage without turning the soil any more than it needs to be, Jake says.
Cover cropping by planting something like grass in the offseason, so the field is not fallow, will protect soil, encourage beneficial microbes and add organic matter. However, Jake says this can be impractical for farmers in areas where there is less than 25 inches of rain per year because cover crops need water too.
Cover cropping is also a form of crop rotation, Jake notes.
Crop rotation is important because monoculture — growing a single crop in a given area — is unnatural. Growing the same crop in the same field over and over will continuously remove the same nutrients from the soil while attracting the same pests and pathogens. Crop rotation switches up which nutrients are most in-demand and staves off recurrences of infestations and disease.
Composting recycles vegetative materials, such as food scraps and crop residue, as useful organic matter that can be added to soil. And when tillage stops, the organic matter will build up in the soil rather than quickly burning off as carbon dioxide when exposed to air.
Biochar is a soil amendment that is more stable than compost while providing many of the same benefits. It’s the solid carbon that remains after heating wood chips, manure or other organic material to a high temperature in the absence of oxygen.
All of these practices and amendments are designed to bring soil back to the natural process that exists in nature.
Carbon Sequestration in Gardening and Farming
One front in the battle against climate change is carbon sequestration. This is the practice of capturing and storing carbon. This can mean planting a tree, which will take carbon dioxide out of the air and hold onto that carbon for many, many decades if allowed to grow to maturity. On farms, crops turn over too fast to sequester carbon, but the soil itself can be a long-term store of carbon when farmers refrain from tilling.
A recent study showed that over 50 days, 90% of cover crop residue that was left on the soil surface burned off as carbon dioxide, Jake says, noting that the study was conducted in Texas, where warmer winter temperatures mean decomposing bacteria and fungi are more active.
Less than two months is not really long enough to consider that carbon sequestered, he says, but maybe 5% of that carbon will stabilize into the type of organic matter known as humus, which is long lasting — maybe for a few months but possibly for many years.
Vegetative material stabilized as finished compost will be harder to break down and, once added to soil, could be considered sequestered, he says. And biochar has a 5,000-year half-life, by conservative estimates.
Understanding and Implementing Permaculture
Pioneered by Australian biologist Bill Mollison, permaculture is the most complex of these concepts, but also the most well defined, Jake says. The term is a portmanteau of permanent agriculture, and the definition is: “the conscious design and maintenance of an agriculturally productive ecosystem, which has the same diversity, stability and resilience that natural ecosystems have.”
The concept seeks the “harmonious integration of landscape and people” to provide people with food, energy, shelter and other needs. That means working with nature rather than against it, and practicing thoughtful observation rather than thoughtless labor. That means recognizing there is a limit to what a system can produce and overshooting that limit will degrade it.
The 12 Principles of Permaculture
- Observe and Interact
- Catch and Store Energy
- Obtain a Yield
- Apply Self-Regulation and Accept Feedback
- Use and Value Renewables
- Produce No Waste
- Design from Patterns to Details
- Integrate Rather Than Segregate
- Use Small, Slow Solutions
- Use and Value Diversity
- Use Edges and Value the Marginal
- Creatively Use and Respond to Change
Jake wants every gardener — every citizen scientist — to know that they have an important role and can effect change.
If you haven’t already listened to my conversation with Jake Mowrer, you can do so now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
Have you implemented regenerative agriculture or permaculture practices? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
joegardener Online Gardening Academy™: Three popular courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting.
joegardener Online Gardening Academy Master Seed Starting: Everything you need to know to start your own plants from seed — indoors and out.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
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