4 Ecosystem Processes: Diversity – groundedregenerativeblog.com

4 Ecosystem Processes: Diversity (Community Dynamics)

Succession (No, Not the HBO Series)

In 1687, mathematician Sir Isaac Newton published the Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) which described the laws of motion for objects and systems. Newton’s first law of motion states that an object in motion tends to stay in motion unless acted upon by outside forces. Similarly, an object at rest tends to stay at rest unless it is acted upon by an outside force. This is known as the Law of Inertia. Earth, along with the natural systems contained within it, are in constant motion so they obey the Law of Inertia. In fact, every second of every day on Earth can be thought of as an invisible battle between natural systems that are trying to keep the ball of life rolling and outside forces that are trying to bring them to a stable resting point. Stability and uniformity can be good qualities, but too much of a good thing is a bad thing in this case. When everything is the same and extremely stable, there are no gradients for energy to make anything happen. Many scientists believe this is the inevitable fate of the universe, thanks to entropy. Thankfully, that’s billions of years in the future. For now, we living organisms have a powerful weapon in our arsenal to fight against the forces seeking to create a uniform world where nothing happens anymore. That weapon is food.

Food is simply a concentrated piece of energy and nutrients that living organisms internalize and use to their benefit. Our human digestive systems are designed to absorb nutrition from things like strawberries, sandwiches, salads and soups. Not everyone is like us, though. If you asked many types of microbes what they think food is, you’d look ridiculous because they can’t understand you. Despite this lack of communication, we know through observation that some microbes gain their nutrition from the energy and nutrients contained within rocks. Thank goodness for them because barren landscapes like rock faces or deserts are examples of systems largely “at rest”, biologically speaking. The compounds that make up the rocks and desert sands are chock full of energy and nutrients, but they are in very stable bonds with each other and are quite happy to remain in their current form. Therefore, it takes an outside force to break the compounds apart and get them moving into and out of the bodies of living organisms. In nature, this outside force is often the powerful chemical compounds produced by microbes.

The first organisms to extract energy and nutrients from an environment are called “pioneer species”. Examples include bacteria, fungi, lichens, mosses and others that multiply quickly after colonizing previously lifeless conditions. Given enough time, the pool of energy and nutrients that are bioavailable (available for living organisms to consume and use) will increase, which allows the system to support more complex forms of life. This process is called “ecological succession“. There are two categories of ecological succession. The first is “primary succession“, which describes the initial transformation of a lifeless habitat, such as the colonization of bare rock by microbes. “Secondary succession” refers to the transformation of a previously living habitat after a major disturbance, such as a forest recovering from a fire. In both cases, succession can be thought of as the invisible hand that moves a habitat’s composition toward intermediate species and a final “climax community“, such as grassland, savanna or forest communities. Annual rainfall is a key variable determining the composition of the climax community, with higher humidity and rainfall encouraging climax communities with trees and drier regions encouraging the formation of grasslands.

To better understand succession, let’s look at the youngest piece of land on planet Earth. On October 14, 1963, a volcanic eruption off the southern coast of Iceland became noticeable on the surface. The volcanic eruption began at 426 feet below sea level. It wasn’t until June 5, 1967 that the eruption ended, leaving Surtsey Island to cool and become the 0.50 square mile piece of real estate we see today. Volcanologists, botanists and ecologists have been studying it rigorously to understand how ecosystems develop from scratch. The images below show just how quickly succession proceeded on the once barren, steaming piece of exposed lava rocks. According to UNESCO, “Since they began studying the island in 1964, scientists have observed the arrival of seeds carried by ocean currents, the appearance of moulds, bacteria and fungi, followed in 1965 by the first vascular plant, of which there were 10 species by the end of the first decade. By 2004, they numbered 60 together with 75 bryophytes, 71 lichens and 24 fungi.”¹

Succession isn’t just a topic for biologists and ecologists. It’s a relevant agricultural point of emphasis. First and foremost, the soil that we all depend on is a product of succession. David Montgomery, geologist turned regenerative advocate, writes in The Hidden Half of Nature that, “Soil is curious stuff, part mineral and part organic, a weathered blanket of rotten rock and dead things. With a typical thickness of less than three feet, soils vary depending on the bedrock, climate, topographic position, and vegetation.” Rotten rock is a beautiful description of how biotic and abiotic forces wear down parent material into sand, silt and clay. Pioneer species speed up the process exponentially as they extract energy and nutrients contained within the parent material and bring them into the realm of the living. The carcasses of these heroes pile up over time and become nearly half of the organic matter in the soil.² Available fertility, energy and water build up over time as soil minerals and organic matter accumulate, allowing land that was once barren or disturbed to become fertile soil able to support increasingly complex ecosystems teeming with life.

Understanding this process helps farmers, ranchers and advisors design management systems that mimic natural succession and reap the benefits it provides. One such benefit is a buildup of soil over time, rather than it eroding away. From a business standpoint, losing topsoil is costly because it is the most fertile, microbially-active and, consequently, productive portion of the soil profile. From a macro-geological standpoint, human civilization simply can’t afford to lose fertile soil year after year, decade after decade. To put into perspective just how thin the supply of soil is, three feet of soil depth (on average) out of the 4,025 miles to the center of the Earth represents 0.000014% of the planet’s radius. This means the layer that sustains all life and human civilization as we know it is equivalent to a sheet of paper on top of 3.32 Eiffel Towers. That’s all that separates us from starvation and extinction. It’s a sobering thought, but it’s one that should engender a desire to protect and build up this life-sustaining layer by mimicking the succession process that built it in the first place.

The fact is that all soils began as bare rock at one point in time. Succession driven by biology built soil upward from the rocky surface into what we see today. Many North American and European farmers are blessed with deep soils above the layer of parent material, so it’s not inherently obvious that the soil is 1) a thin layer and 2) was built up from rock over long stretches of time. However, this is the story of every soil on Earth, even the deepest and most fertile. No matter where you find yourself, the soil is like a thin layer of frosting on top of a thick, rocky cake. To visualize this concept, I’ve added pictures of soil on top of underlying rock from my travels to other countries. Each picture tells a unique story of how succession and the drift toward more complex communities happened in that location. Although the details are unique, it is the same basic process that built soil in each location, as well as everywhere else on the planet. The universal methods of succession that build soil up from bare rock are captured in the Six Principles of Soil Health and the Three Rules of Adaptive Stewardship, which is why they are applicable to every operation, no matter the location. What differs is the specific implementation of the methods to fit the individual operation’s context.

To summarize, soil is largely a byproduct of biological activity. More biological activity means more soil is built. Just how quickly can soil actually be built? That question deserves a standalone article, which you can read by clicking here. In short, it does not take a hundred years or more to build an inch of topsoil IF there is active biology present. In an agricultural setting, the biggest influence on biological activity is our management, which can either speed biology up or slow it down. Taken to the extremes, long-term management practices are powerful enough to build soil, promote succession and regreen a desert or slow biological activity and desertify a fertile piece of land. This is why I believe it’s helpful to think about inertia. Our management practices are like the outside force that determine whether the biological system in motion speeds up or slows down. Recall that the odds are already stacked against us because there are always outside forces present that are constantly working to transform compounds and ecosystems into stabler, slower moving forms. Our job is to ensure that the ecosystems our farms and ranches are built upon have enough resources to overcome these forces and remain complex. After all, the living creatures that comprise ecosystems are made up of complex, unstable compounds formed by reactions that are extremely unlikely to happen on their own. We need to make sure that our management practices promote more of these unfavorable reactions, not fewer. (Unfavorable, in this case, refers to a reaction that does not happen spontaneously. Energy needs to be added to make them happen, like rolling a ball up a hill until it reaches the peak where it can roll down the other side on its own. Unfavorable reactions speak nothing of whether they are “good” or “bad”.)

One unfavorable reaction we want to encourage is the fixation of the dinitrogen (N₂) gas that makes up 78% of the air. Natural processes led to this incredibly stable compound which is happy to remain as N₂ for decades. This is a huge problem for living organisms because Nitrogen is needed in large quantities, as it is a key constituent of proteins and genetic material. For this reason, Nitrogen is often the nutrient that limits biological activity in nature. So, how did living organisms solve this problem? Enzymes. Enzymes make chemical reactions happen millions of times faster than they would occur on their own, such as the breaking apart of N₂. This reaction is facilitated by a microbial enzyme called nitrogenase. Chemists still don’t fully understand how nitrogenase is able to separate N₂ so efficiently. This is why we still have to unlock Nitrogen by brute force in fertilizer factories. In those factories, N₂ gas is heated up to 300 degrees Celsius and compressed 200-300 times normal atmospheric pressure. Only then will the two Nitrogen atoms release their grip from one another. The Haber-Bosch process, as it known, is so energy intensive that it makes up 1-2% of the world’s energy use.³ Miraculously, nitrogenase produced by single-celled microbes is able to fix Nitrogen into bioavailable ammonia (NH₃) at moderate outdoor temperatures and normal atmospheric pressure. Plants that associate directly with Nitrogen-fixing microbes have a distinct advantage in nature, which is why species like clovers and red alder trees are are often among the first pioneer species on the succession timeline that reappear after a major disturbance. A common example you can see for yourself is an area that has heavy foot or vehicle traffic. Oftentimes clovers will be the first plant species to dominate if further disturbances are held to a minimum. The picture of clover below shows this exact situation.

Plants that associate with Nitrogen-fixing microbes increase the pool of available Nitrogen in the soil through their exudates and decomposing tissue. The soil is now able to support organisms that can’t fix their own Nitrogen, like grasses. Similar situations are observed with other nutrient deficiencies, not just Nitrogen. For instance, crabgrass and dandelions grow well in Calcium-deficient soils and release available Calcium throughout their life cycle.⁴ In addition to nutritional deficiencies, poor soil structure also gives certain plants a competitive advantage over others. Knotweed, plantain and quackgrass are examples of plants that outcompete others in compacted soils. This is why diversity is so important to soil health and succession. Every microbe, plant and animal has a unique nutritional composition that adds to the total pool of available nutrients which improves soil structure through increased biological activity. Better nutrient balance and soil structure creates healthier conditions for life to cycle energy, nutrients and water more efficiently. Talk about positive compounding and cascading effects!

As succession proceeds, height becomes a more important competitive advantage for plant species in crowded conditions, assuming no major disturbances that reset the succession clock. Regions with adequate rainfall support the growth of extremely tall plants like trees, while lower rainfall regions can only support shorter woody species, grasses and forbs. Factors like altitude, sunlight and temperature affect the composition of climax communities as well, but precipitation is the most important factor, as you can see from the maps below.

Just like a good friend after a bad breakup, succession tells us that everything happens for a reason. Species only survive and reproduce when the conditions are right for them in that time and place. There are thousands of variables that determine the livability of an ecosystem. A simple, yet important example is the level of oxygen in the air. Humans would not be able to survive if atmospheric oxygen levels suddenly disappeared. The same demise of all other oxygen-dependent organisms would be met if oxygen were no more. This singular change in conditions greatly affects who can survive and who can’t. As it turns out, less developed ecosystems, such as bare rock or a charred forest, share common conditions that make certain strategies work better than others. These are the strategies that pioneer species use at the beginning of succession. Pioneer species eventually change environmental conditions so much that other strategies become a competitive advantage. Intermediate species and climax community species tend to deploy these strategies as they strive to survive in a more developed ecosystem. Read on to learn about these strategies and how our management practices create the conditions that incentivize them.

Survival of the Strategies

The desire to reproduce is a ubiquitous trait among populations of organisms. This makes sense because a species that doesn’t care to reproduce would last approximately one generation. What’s interesting is that the universal desire within microbes, plants and animals to pass on their genes is driven by signals contained within the genes themselves. However, reproduction cannot happen out of thin air. The appropriate resources must be available and they must be utilized by an organism for offspring to be produced. The manner in which organisms deploy take advantage of available resources and local environmental conditions differs greatly. Similarities can be drawn from sports, war and business. The overarching goals are shared between groups (win the game, win the war or outlast business competitors), but the strategy to achieve each of these goals varies tremendously between groups. For example, some basketball teams prioritize hard-nosed defense, while others prioritize flashy offense to win the championship. Theoretically, the best strategies are preserved over time because they outlast other strategies. This is ecology in a nutshell. Ecologists study how populations and individuals compete and collaborate with one another as they work to pass on their genes to the next generation. Although reproductive strategies are unique, ecologists are able to place species onto a spectrum of strategies, based on certain shared traits. Organisms that fall on one side of the spectrum are called “r-strategists“, while organisms on the other half are called”k-strategists“.

The “r” in r-strategist stands for reproduction. These organisms think that having one kid at a time seems like a risky plan, which makes sense because their genes die out if that child doesn’t survive to reproduction. So, r-strategists spend their reproductive energy on the production of huge numbers of offspring. It’s nature’s version of not putting your eggs in one basket. The drawback is that energy and nutrients are spread between many individuals, making each individual relatively weak. Because of this, a good portion of offspring die before they themselves reproduce. R-strategists don’t mind because it’s all part of the plan. Only a small percentage of their babies need to survive and reproduce to cause the population to rise quickly.

What kind of situation could possibly warrant this irresponsible parental behavior? It turns out that this strategy is particularly well-suited in conditions that are resource-poor, low competition and/or out-of-balance, such as bare rock or a charred forest after a major fire. Not many organisms can reliably reproduce in these harsh environments, so r-strategists’ shotgun approach gives them a huge competitive advantage. The more offspring for them, the more likely a few will survive to sexual maturity. If you’re thinking that this sound suspiciously similar to the description of pioneer species, your hunch is correct. Pioneer species are most often r-strategists because they deploy these reproductive strategies.

Other traits that help r-strategists pass on their genes include the tendencies to mature quickly, to reproduce at a young age and to have very short gestation periods. All of these factors result in the defining characteristic of r-strategist populations: quick exponential growth, meaning it takes them a very short amount of time to take their population size to tremendous heights. This flash-in-the-pan growth is unsustainable as the population outpaces available resources. The population of these species will subsequently crash and yo-yo up and down wildly throughout time. The capricious nature of r-strategist populations is a crazy ride, but it’s an important first step toward improving energy, nutrient and water cycling in the local environment. They essentially set the table for more diverse forms of life to survive as long as there are no further disturbances that reset the succession clock. Examples of r-strategists include bacteria, mosses, insects, oysters, salmon and rodents.⁵

The important takeaway from an agricultural point of view is that the organisms we consider pests, namely disease-causing microbes, crop-munching insects and yield-robbing weeds, tend to be r-strategists/pioneer species. Their job isn’t to make the lives of farmers and ranchers miserable. It’s actually to colonize a system that’s out-of-whack, create some semblance of order and set the table for other species to move in and join them. This is the real first step on the road to minimizing pest outbreaks permanently without tillage and pesticides. As Sun Tzu, author of the 5th century B.C. classic The Art of War, said, “If you know the enemy and know yourself, you need not fear the result of a hundred battles.”⁶ Let’s take a couple of examples. We know that pigweed is well adapted to grow and produce up to 117,000 seeds per plant⁷ in compacted soils with low competition. Similarly, thistles prefer “overused and otherwise disturbed land.”⁸ As for insects and microbes, their bread and butter is targeting unhealthy plants and animals.^9,10With this knowledge in hand, farmers and ranchers can deter and even prevent detrimental pest outbreaks by promoting the opposite conditions that naturally lead to their domination. In the landscape, opposite looks like a well-aggregated soil with minimal compaction that supports a rich, diverse biological community who keep the pest in check and continue to positively influence the cycling of energy, water and nutrients. Therefore, it’s critically important that farmers and ranchers find ways to minimize disturbances like tillage and pesticide applications that leave the soil bare, create compaction, reduce diversity and hinder energy, nutrient and water cycling. Disturbances like these have their use in the short-term, but the long-term effect is that they continually reset the succession clock back to the point where r-strategists, like pigweed, thistles, aphids and grasshoppers, thrive.¹¹In living organisms, opposite looks like healthy individuals with strong innate and adaptive immune defense systems and a rich, diverse microbiome.

Now, let’s assume a farmer or rancher heeded this advice and did not reset the succession clock of their field or pasture. They implemented practices like adaptive multi-paddock (AMP) grazing, minimized tillage passes and planted cover crops between their cash crops. As r-strategists reproduce and improve the natural system, k-strategists eventually show up and join the party. “K”, in this case, is the abbreviation for a term called “carrying capacity“. Carrying capacity refers to “the average population density or population size of a species below which its numbers tend to increase and above which its numbers tend to decrease because of shortages of resources. The carrying capacity is different for each species in a habitat because of that species’ particular food, shelter, and social requirements.”¹² As you can see in the chart below, K-strategist populations rise much more slowly and do not yo-yo near as wildly as r-strategist populations. K-strategist populations hover around the carrying capacity of the land as time advances, assuming conditions are not disturbed by a natural or agricultural event. Another difference is that k-strategist species produce lower numbers of offspring per reproduction event. While this does run the risk of putting more eggs in fewer baskets, each individual offspring tends to be larger and stronger in comparison to r-strategist individuals which increases the odds that each individual will survive to reproduction. This strategy works well when conditions provide sufficient available energy, nutrients and water.

Other strategies that k-strategists exhibit are that they tend to have long gestation periods lasting several months, mature slowly (thus extended parental care), and have long life spans. Lastly, and most importantly for agricultural purposes, they tend to inhabit relatively stable biological communities, such as late-successional or climax forests.¹³Examples of k-strategists include elephants, eagles, whales and, of course, humans.

Schematic of the general changes occurruing when fresh plant residues are added to a soil. The top graph shows r-strategists rapidly consume easily digestible, water-soluble compounds, leaving resistant compounds for K-strategists. The bottom graph shows a phenonmenon known as the "priming effect": Intense microbial activity initially lowers total soil humus, but the level is higher by the end of the process. Courtesy of Brady & Weil (2017)

Annuals, Perennials and Microbes (Oh my!)

To summarize what we’ve learned so far, environmental conditions affect species composition and species composition affects environmental conditions. As one changes, so does the other. This two-way relationship is particularly true with plants and their surroundings. Harsh conditions tend to favor plants that can muster up enough energy to live for one growing season. We call these plants “annuals”. As you may have guessed, annual plants tend to be r-strategists and pioneer species. The three terms are not exactly interchangeable, but their definitions do heavily overlap. The main objective of annual plants is to grow their population size rapidly with quickly maturing individuals that produce thousands of seeds in their first and only year of life. Only after years of living roots amending the soil and its biological community will conditions be able to support more “perennial” plants that live for many years. Perennial plants tend to exhibit characteristics more like k-strategists and make up a significant portion of intermediate and climax communities. Check out the image below and pay attention to the timeline. Short, annual plants show up and set the table for taller, perennial plants to survive later on.

One of the biggest changes over time that allows perennial plants to survive at a higher rate is a shift in soil microbial species. Many annual plants can survive to reproduction when microbial activity is scarce, but most perennial plants require a healthy soil with diverse, rich populations of soil microbes to thrive. Fungal activity is a particularly important microbial indicator of whether a soil system is better suited for annuals or perennials. One study found that early-successional plants (which tend to be annuals) grew 40% smaller with an inoculation of beneficial soil fungi relative to non-inoculated controls. Late-successional plants (which tend to be perennials) grew 383% larger with the inoculation relative to the non-inoculated controls.¹⁴ Another study found that perennial warm-season C₄ grasses and forbs generally benefited significantly from symbiotic relationships with soil fungi, whereas biomass production of the cool-season C₃ grasses was not affected. In addition, fourteen of the fifteen perennial legumes were highly responsive to mycorrhizal fungal inoculation.¹⁵ The reason why fungal activity influences plant composition so drastically is due to the numerous services they provide to the soil and plants. Certain plants have developed strategies to withstand the absence of these services, while others have developed strategies that require them. This makes sense in light of the fact that r-strategists/annual plants are individually endowed with lower inputs of energy and nutrients from their parents (what was called “weaker” earlier), meaning they can survive when the going gets tough and resources are scarce. On the other hand, k-strategists/perennial plants require more energy and nutrients per individual, so it makes sense that they struggle without the myriad services handed to them by soil fungi and other microbes. One could say perennials are the Millennials of the plant world because they only tend to show up when conditions are comfortable and their demands have been met by others. Just for the record, I’m not saying that… but one could.

Back to fungi. The services that they provide include residue breakdown, nutrient scavenging and defense against root fungal pathogens.¹⁶ Arguably the most important function that soil fungi provide is their ability to reinforce soil macroaggregate tensile strength.¹⁷ Macroaggregation refers to the binding of tiny microaggregates made of sand, silt, clay and organic debris. This process is of utmost importance for farmers and ranchers thinking about succession because macroaggregation reduces compaction and increases soil function, thereby creating an environment conducive to greater diversity. A soil that is not well-macroaggregated resembles a jar full of flour because the microaggregates are fine and fill most of the pore space. Think about what happens to water as it is poured onto the flour. Not ideal. A well-aggregated soil resembles a jar full of marbles with adequate pore space that allows water to infiltrate and be held for later use. Water is held because the marble-like macroaggregates are more like round sponges. They are porous and are full of electrically charged, carbon-rich organic matter that holds onto water and nutrients exceptionally well. Gas exchange is also positively influenced as air containing oxygen and nitrogen is able to flow into the soil profile, while CO₂-heavy air rises upward, hopefully to be captured by a growing leaf and used once again as plant food. Lastly, soil organisms larger than bacteria require proper macroaggregation to survive and provide ecosystem functions that benefit farmers and ranchers. For example, one study found that “changes in soil nematode assemblages corresponded largely to those in soil porosity of the macroaggregates.”¹⁸ The authors also note that macroaggregate porosity likely supported the observed high density of nematodes that consume bacteria and make nutrients plant-available. All of these benefits are impossible without the work of soil fungi. I recommend reading The Biology of Soil Compaction by the Ohio State University for a very informative explanation of the process of macroaggregation.

Farmers and ranchers need to know this information because management practices affect soil fungi and, consequently, succession. The practices that harm fungi include glyphosate application¹⁹, fungicide application^20,21, tillage²² and even the removal of animals from the landscape²³. This is likely why research investigating over 2,100 soil samples from mainland France found that the highest values of fungal density came from natural or semi-natural environments (forests and grasslands), and the lowest values came from agricultural soils (crops and vineyards & orchards).²⁴ Similarly, a study out of the UK observed lower fungal populations and lower fungal-to-bacterial ratios (F:B) in agricultural plots, prompting the authors to write that “the diversity of arbuscular mycorrhizal fungi is strikingly low in arable sites compared with a woodland.”²⁵ Given all of the benefits that soil fungi bring, these are not encouraging findings. Even more unfortunate is that a soil with a low F:B ratio is commonly found in early succession landscapes, which we know gives a competitive advantage to weeds (and pest insects and pathogenic microbes).

Although tillage and other disturbances can have their purposes in the short-term, the net result is negative in the long-term. Over time, high disturbance regimes dramatically slow down an ecosystem, limiting the efficiency of the Energy, Water and Nutrient cycles to the point where it resembles the conditions of an early succession landscape. This is the origin of the never-ending cycle of disturbances and worsening conditions that many farmers and ranchers find themselves spinning inside. Whether producers decide to get out of the cycle or continue to run on it depends on which of the two approaches they take to address their issues.

Fight the Power

When it comes down to it, there are really only two strategies for creating an ecosystem that won’t be dominated by pests, disease and weeds. The first is to eliminate everything and everyone. Nobody can dominate if nobody exists, right? This idea of sterilization is the approach utilized in hospital operating rooms, for example. Sterilization makes sense in a surgical setting because the human body’s natural barriers are broken open and foreign objects come into contact with a patient’s internal tissue. In addition, the surgery and/or medication often leaves the patient’s immune system weaker, making them more vulnerable to an infection by microbes. Therefore, the safest management practice during surgery is for medical professionals to ensure that their instruments and hands do not expose the patient to an opportunistic microbe. This strategy of sterilization is great for avoiding infection in the hospital during acute treatments, but it isn’t advised if we are trying to achieve long-term health and balance in a biological system.

For one, disturbances that are designed to kill (i.e. pesticides, antibiotics, antifungals, etc.) run the risk of eliminating not just the target group, but large swaths of beneficial organisms. Let’s use our own guts as an example. The density of bacterial cells in the colon alone has been estimated at 10¹¹ to 10¹² (10 with 11 to 12 zeroes!) per milliliter, making the colon one of the most densely populated microbial habitats known on earth.²⁶ Do you think we would be able to survive if all bacteria in our colon were “bad guys”? Of course not! The vast majority of them are either neutral or beneficial to human health.²⁷ Only a select few, such as Clostridioides difficile, or C. diff (a highly contagious bacterium that causes diarrhea and colitis) cause harm under the right circumstances. The right circumstances, according to the prestigious Cleveland Clinic, involve a wiping out of the microbial population. They write that, “C. diff often infects people who’ve recently taken antibiotics. A course of antibiotics is the most common cause of C. diff infection. Most antibiotics, including broad-spectrum antibiotics meant to target a wide range of microorganisms, are ineffective against C. difficile. But they’re effective against the other bacteria living in your gut, both the bad and the good kind. Using them upsets the balance in your gut microbiome, allowing C. diff to dominate while diminishing other bacteria.”²⁸ This is why people are 7 to 10 times more likely to get C. diff infection while taking an antibiotic and during the month after.²⁹ Despite everyone’s best intentions, broad spectrum antibiotics unintentionally create an early succession landscape with few natural enemies which gives a competitive advantage to the opportunistic C. diff bacteria.

So, if antibiotic use can have the unintended consequence of providing a competitive advantage to a deadly bacteria, is it possible that fungicides, herbicides, nematocides and other agricultural killing agents also inadvertently promote certain pests and disease? Recent research indicates the answer is yes. Take insects, for example. Similar to gut microbes, the abundance of insects in nature is mind boggling. One estimate in North Carolina calculated that there were approximately 124 million invertebrates per acre, of which 90 million were mites, 28 million were springtails, and 4.5 million were other insects.³⁰ Thank goodness the majority of these insects aren’t harmful in agricultural production.³¹ There’s no way we would ever produce a crop if all insects were “bad guys”! In fact, we rely on the millions of beneficial insects to provide us services, so it’s imperative that we investigate whether or not the chemicals intended to take out pests are harming the rest of the population as well. Unfortunately, studies are showing that beneficials are in fact harmed, just like antibiotics hurt a large range of gut microbes. One such study found that insecticide seed coatings on soybean significantly reduced natural enemy communities³², while a study from Sweden observed that insecticides killed natural enemies and increased insect damage in a cabbage crop.³³ It shouldn’t come as a surprise, then, that a recent study found pest insects to be 10-fold more abundant in insecticide-treated corn fields than on insecticide-free regenerative farms.³⁴

Echoing the Cleveland Clinic’s description of why C. diff can run amok after taking broad-spectrum antibiotics, Michigan State University writes, “When broad-spectrum insecticides are applied, pest and non-pest species are killed and the balance of the community is disrupted. For example, pesticide use in pear orchards to control codling moth can also destroy the natural enemies of pear psylla. In the absence of its natural enemies, pear psylla can reach high densities and cause significant damage to the fruit.” ³⁵ Imagine the time and money spent by the farmers that think they’re doing the right thing for their crop only to make the situation worse. It’s an unfortunate unintended consequence of conventional farming methods.

For more information on the subject, check out the research that Dr. Jonathan Lundgren has complied at the Ecdysis foundation website, as well as this database compiled by the UK’s Agriculture and Horticulture Development Board to learn more about specific insecticides and their effect on natural enemies.

How about the fungi that we encounter in agriculture? These microbes represent the largest group of plant pathogens and account for around 14% of global crop yield losses annually³⁶, so just the mention of rhizoctonia, phytophthora, tar spot, powdery mildew or any others can make a farmer want to reach for the fungicide. Is this always the right response, though? Let’s review the facts. First off, fungi exist in large numbers nearly everywhere on the planet, especially in the soil. Globally, the total length of mycorrhizal fungal (fungi living symbiotically with plant roots) mycelium in the top 10 cm of soil is more than 450 quadrillion km, or half the width of the Milky Way galaxy.³⁷ In addition to their sheer quantity, it appears that species diversity is also enormous as scientists have only discovered and named roughly 3-8% of all fungal species on the planet.³⁸ Once again, many, if not most, of them are not harmful to human health or agricultural production. We’d all be in big trouble if most of them were the pathogenic, zombie-creating monsters depicted on TV and the movies! To the contrary, beneficial fungi are prevalent in nature and society relies on the numerous indispensable services they provide.³⁹

It’s true, though, fungi don’t always behave in a manner that humans find helpful. Sometimes they cause illness and crop yield loss. In those cases, fungicides or antifungal medication may be prescribed to solve the issue. Sometimes this is the right course of action, but sometimes it isn’t. We need to think about the consequences of annually applying these chemicals and decide whether the short-term relief outweighs any long-term unintended consequences. One such consequence appears to be the killing of beneficial fungi^40,41 just like we saw with bacteria in the gut and insects in the field. One fascinating study found that the use of fungicides and subsequent decline in arbuscular mycorrhizal fungi richness in croplands was enough to reduce Phosphorus uptake by 43%.⁴² Interestingly, another study found that the attempt to curb a fungus involved in worldwide amphibian declines with agricultural disinfectants and fungicides actually led to increased fungal disease in the amphibian community.⁴³ At the end of the day, managing fungal pathogens is a tricky issue because the extent of damage is never quite so straightforward, just like everything else in agriculture and ecology. A lot depends on the species of fungi, the active substance, the mode of action, the mode of application and the dosage.^44,45 With that said, fungicides aren’t the only disturbance that is potentially harmful to beneficial fungi. Many agricultural operations complete the one-two punch by tilling the soil and disrupting soil fungal communities further.^46,47 Among the negative consequences of tillage are the tendency to homogenize the soil’s physicochemical properties and fungal species contained with it⁴⁸, as well as the tendency of conventional tillage regimes to create an environment where “fungi can utilize mature plant residues that are turned into the soil with tillage as pioneer colonizers, and then produce large numbers of conidia (reproductive spores).”⁴⁹ Sound familiar? This is the description of an early succession landscape and the r-strategists that thrive in those conditions. Instead of setting ourselves up for a future of resilience and health, the long-term unintended consequences of fungicides and tillage appear to be a reduction in beneficial services and an increase in disease risk.

It’s important to emphasize at this point that antibiotics, insecticides, fungicides and other chemicals are simply tools in our toolbox. Just because their irresponsible use can lead to some bad outcomes doesn’t mean we should never use them. We just need to be much more judicious with how and when we use them as we collectively reduce the need for them. A little bit of humility will also go a long way because the organisms we’re targeting have been using chemical warfare for much, much longer than we have. They’ve got centuries of experience under their tiny belts that help them survive, evade, resist and escape from our best efforts, and it’s a growing concern in both public health and agriculture.

Our attempt to sterilize away the “bad guys” is not only killing beneficial species, it’s creating chemical resistance in the very organisms we’re attempting to get rid of. Ever since 1928 when Andrew Fleming accidentally discovered a fungal compound that killed bacteria, the scientific world has embraced the concept of using chemistry to wipe out our adversaries, both big and small. Many public health victories followed and antimicrobial drugs were thought to be an integral part of a future that would phase out infectious disease once and for all. In fact, U.S. Secretary of State George Marshall stated in 1948 that “The war against diseases has been won”.⁵⁰ Most of us were taught Fleming’s serendipitous discovery of penicillin and the subsequent public health victories that followed, but how many people know of his prediction just 8 years later in 1936 that bacteria would become resistant to them? Fleming said his discovery would cause, “a revolution, but doctors will overuse it, and because bacteria have to survive – they are very very clever – they will become resistant to it.”⁵¹ Unfortunately, Fleming’s observations of the shifty nature of microbes have proven prescient and mankind has not won the war against diseases. We’ve scored many victories along the way and we should all be thankful for medical breakthroughs of the past 150 years, but all-out victory against disease has not been achieved. Further, treating microbes as the enemies in a war is a mistake for a bevy of reason, not least of which is the tendency to create more resilient pathogenic microbes. The same goes for pest insects and weeds.

To understand why organisms gain resistance to chemical treatments, it’s important for us to step outside of the bounds of our human experience and think about life from the perspective of microbes, plants and insects. Humans take a very long time to reproduce and typically pass on their genes to fewer than three offspring, roughly speaking. We are k-strategists through and through. Other organisms, especially microbes, reproduce much more quickly and have many more offspring per individual. This is important because one of the most common ways an organism becomes resistant to a medicine or pesticide is through random genetic mutation. Genes are the instructions contained in every cell that an organism uses to produce what it needs to survive. Cells, and the genes contained inside each cell, are constantly replicating themselves to stay healthy and functional. Sometimes the sequence of genes doesn’t get copied perfectly, the proofreading system doesn’t catch it and the change gets passed on to the new cell. This is a random genetic mutation, and sometimes it provides an organism with a brand new ability that others around it don’t have. Increasing the number of individuals replicating and the speed at which they are replicating are two ways of increasing the odds that a random mutation will occur in the population. Many times the mutation has no effect, but sometimes the changed sequence of genetic material has a positive or negative effect on the organism. Take E. coli bacteria. Given the right conditions, a single E. coli bacteria can become a million in only 8 hours because they are able to replicate themselves in under 20 minutes.⁵² With every replication, there is a tiny chance that an individual will randomly mutate. Now, consider what happens when a change is made to the environment so that one mutation could confer a massive competitive advantage to an E. coli individual. Scientists say that this “pressure” is a big driver of change over time. For E. coli, the presence of an antibiotic drug is a cataclysmic change to the environment and most of the bacteria are killed during the treatment. The antibiotic puts enormous pressure on individuals to discover a way to defend themselves against its mode of action. Given the speed and volume of E. coli’s reproduction, there is a decent chance that one bacteria’s genes will randomly mutate in such a way that an individual can now sidestep the antibiotic. This mutant will now replicate like gangbusters and pass on its resistant genes because the vast majority of its neighbors have died from the antibiotic and it has increased access to available space and resources. There is a decent chance that the mutant E. coli strain with the resistant genetics will quickly grow in population size and dominate the new landscape. This short video by Harvard University shows a real experiment showing this process that resulted in a strain of bacteria that survived 1000x the dose that would kill a normal strain. Such is the advantage of reproducing at high speeds and high numbers.

Another way in which organisms overcome pressure relates to a relatively new branch of genetics is called epigenetics. Until recently, conventional science taught that genetic changes can only happen by a physical change in the sequence of genetic material. This is a key teaching point in classical genetics. We now know that this is not always the case. The products of an organism’s genes can also change by physically switching the genes on and off, or by making them produce more or less, like a dimmer switch for a lightbulb. Researchers are just beginning to investigate the role of epigenetics in resistance. One group of scientists write that, “Since well-documented biochemical or genetic changes fail to fully explain mechanisms underlying antibiotic resistance, it is becoming increasingly evident that we need to shift our focus to newer, nonclassical mechanisms such as epigenetic regulation.”⁵³ Although the mechanism of change is different than classical genetics, the same concept of competitive advantages applies. Individuals are more likely to pass on their genes when they are able to change in such a way that helps them overcome pressure from their environment. They then have a better chance to pass on these advantages conferred by the on/off/dimmer switches to their offspring or replicates.

Finally, microbes are particularly quick to respond to changing conditions because of their unique ability to share genetic information non-sexually with their neighbors in a process called “horizontal gene transfer“. Horizontal gene transfer is in contrast to “vertical gene transfer” which is the passing down of genes from parent to offspring. During a special form of horizontal gene transfer called “conjugation”, bacteria and archaea transfer genes to each other in the form of a structure called a plasmid. These genes are separate from the main string of genetic material, a.k.a. the “chromosomal DNA”, that codes for many day-to-day tasks. The genes inside of plasmids are important because some of them provide unique competitive advantages against pressures, such as antibiotic resistance.^54,55 As you can see from the image below, the F plasmid is copied and transferred to its neighbor through a structure called a pilus. Although this may sound and look like sexual reproduction, it is considered non-sexual because the transfer can happen with non-sexually compatible neighbors. After the transfer has been made, there are now two bacteria that have the genetic ability contained inside the F plasmid. Horizontal gene transfer is an absolute game-changer for microbes because genes that are able to mix, match and transfer to one another build resilience against disturbances and/or changing conditions. I like to think the human equivalent is our ability to verbally share ideas and information with other humans. We can drastically reduce the learning curve on all kinds of processes with our ability to share what works and what doesn’t work, just like in horizontal gene transfer. Genes are, after all, pieces of coded information.

There are two other common methods of non-sexual gene mixing and transferring called transformation and transduction. In transformation, a bacterium can absorb a free-floating piece of DNA like someone picking up a five dollar bill on the ground. Sometimes it’s more like finding a winning lottery ticket when the genes provide the bacterium with a huge competitive advantage, proving just the high degree of randomness that genes can be shared with one another on the microscopic level. Transduction refers to the DNA that is transferred and shuffled from one bacterium to another by a virus. Although they are not technically living organisms, viruses play a huge role in facilitating genetic diversity on the planet. In fact, scientists estimate that remnants of viral genes make up a relatively large part of modern human DNA. And, not only that, these pieces of DNA likely boost our immune system by helping us to fight off infections.⁵⁶ Imagine how much more influential they are in the fast-paced world of microbes!

Lastly, it’s worth mentioning that fungi are able to share genetic information horizontally with non-sexually compatible neighbors, just in a different manner. This amazing video from UCLA and UC Berkley shows how fungal communities pass around whole nuclei (the main structure containing genetic material) to one another, further blurring the lines between the genetics of one individual organism to its neighbor.⁵⁷

To quote the great Ferris Beuller, life moves pretty fast, especially in the microbial world. The only difference is they don’t have time to stop while they’re looking around and gathering information on a rapidly changing environment. Microbes, and higher order creatures, that have survived to this point have done so largely because of their built-in methods of sensing changes to external conditions and having the ability to react to these pressures. Add sheer random mutation to the mix and you get a resilient population of organisms that can handle many challenges and come out the other side stronger. These are very handy sets of behaviors to have, especially since humans have created enormous change to the planet through the introduction of agriculture thousands of years ago and the mass use of antibiotics and pesticides in the last 100 years or so. Microbes, insects and weeds are simply reacting to these changes in the best way they know how: survive, advance and pass on the advantage. No one is more aware of this fact than the medical community. The Center for Disease Control (CDC) writes that, “Antimicrobial resistance is an urgent global public health threat, killing at least 1.27 million people worldwide and associated with nearly 5 million deaths in 2019, according to a report released in The Lancet.”⁵⁸Examples of antimicrobial resistance in bacteria includes cephalosporin-resistant E. coli, methicillin-resistant Staphylococcus aureus (MRSA) and Klebsiella pneumoniae that is resistant to critical antibiotics. Fungi like Candida auris and parasites that cause malaria are also exhibiting resistance to drugs that worked effectively in the past. One of the biggest dangers of resistance from these microbes is that patients are increasingly administered last-resort drugs like carbapenems, of which resistance is already being observed across multiple regions.^59,60 This is especially dangerous because the discovery and development of new antibiotics have slowed dramatically since the 1990’s. Since then, only three new antibiotics have received FDA approval in the last 30 years.⁶¹ Protecting the efficacy of antimicrobial drugs is of utmost importance if we are to avoid a reversion to the days of fearing that a small cut will turn into a life-altering infection.

We need to realize that there are patterns exhibited in ecological systems of all shapes and sizes, whether it be a microbe, the rhizosphere, the human body, a forest or the planet as a whole. This is why it’s important for us in the agricultural world to study the issues that the medical community are facing. The successes and failures of both fields translate to the other because many of their issues stem from the collective attempt to sterilize our way to health. The trouble is that we simply don’t have enough knowledge to predict all of the negative unintended consequences that result from man’s attempt to strong-arm nature into submission. So, if the medical community accepts that their management of disease has caused negative downstream effects, why has the agricultural community been so slow to recognize that our management practices might be resetting the succession clock and leading to many of the same unintended consequences? It’s time we learn from each other and realize our issues are intimately related. Case in point is the rise in resistance against pesticides.

Starting with insects, scientists estimate that up to 30–40% of crops are lost because of pests⁶², so it is is imperative for global food, fiber and fuel security that these six-legged creatures don’t wreak havoc on our fields and pastures. The primary strategy to keep insects at bay for the past century has been to develop and use industrial chemical products and, as of recently, genetic modification. These products and technologies have their purpose, but scientists have known about the ability of insects to gain resistance to chemical products for over 100 years when it was discovered in 1914 that sulfur lime was becoming less effective at controlling the San Jose scale (a.k.a orchard aphid).⁶³ Since then, the agricultural community has put itself further and further into a chemical arms race with insects. Who’s winning the race is up for debate. The USDA reports that 11 additional cases of resistance to inorganic insecticides were observed from 1914 to 1946.⁶⁴ A major breakthrough in insecticide technology came with the development of organic insecticides, such as DDT. (Side note- DDT, banned in 1972 for its adverse effects, proves that organic/natural products do not automatically translate to “healthy”!) These new organic insecticides initially gave hope to scientists that insecticide resistance would not be achieved, due to their natural origin. Unfortunately, housefly resistance to DDT was already documented by 1947. It turns out that insects don’t really care where a compound comes from. If something is trying to hurt them, they’ll do their best to fight back, and fight back they did. No matter the insecticide class introduced throughout the 20th century, whether it be cyclodienes, carbamates, formamidines, organophosphates, pyrethroids, or even Bacillus thuringiensis (bt), insects figured out ways of sidestepping them, usually within two to 20 years.⁶⁴ Just like antimicrobial drugs, the increased use of insecticides appears to have been a double-edged sword. At the same time as they were killing scores of target insects, they were also placing enormous pressure on our six-legged compatriots that forced them to quickly figure out ways around the chemicals. To do this, insects used a “variety of behavioral, biochemical, physiological, genetic, and metabolic methods to deal with toxic chemicals, which can lead to resistance through continuous overexpression of detoxifying enzymes.”⁶⁵ Individuals that produce these enzymes rapidly became a greater percentage of the population and rendered the insecticide less and less effective against pests. It’s simply another case of survive, advance and pass on the advantage.

So, what’s the extent of insecticide resistance? The University of Clemson reports that as of 2015, “550 insect species have been reported as resistant to 325 insecticides and five insecticidal traits in genetically engineered plants.”⁶⁶ Graphical representation of this data can be viewed below. Another group of scientists estimated in 2023 that “As many as 1000 species of insect pests have developed resistance to different class of insecticides,⁶⁷ and the list keeps growing, including a recent study from November 2023 showing novel resistance by bluegreen aphid to organophosphates, omethoate and chlorpyrifos.⁶⁸ If you believe what the Insecticide Resistance Action Committee (IRAC) has to say then you shouldn’t expect this list to stop growing because they report that cases of insecticide resistance far exceed the cases of other agricultural pesticides.⁶⁹ These findings should cause us in agriculture to think long and hard about whether we will continue to rely on insecticides as our first line of defense against pest insects.

For anyone interested in digging deeper into insect species and insecticide resistance, Michigan State University has a great arthropod pesticide resistance database that is open to the public.

And the fungus among us? As was mentioned earlier, fungi represent the largest group of plant pathogens and pose possibly the greatest biotic challenge to global food security⁷⁰, so it’s crucial that we figure out whether or not they’ve developed resistance to the chemicals we’ve been spraying on them for decades. Unsurprisingly, the answer is a resounding yes. Resistance to fungicides first reared its ugly head in the 1960’s and has become a growing issue ever since.⁷¹ Oklahoma State University reports that, “Fungicide resistance problems in the field have been documented for nearly 200 diseases (crop – pathogen combinations), and within about half of the known fungicide groups. Many more cases of resistance are suspected but have not been documented.”⁷² They go on to describe the process of how this happens. Stop me if you’ve heard this one before. “The build-up of resistant strains is caused by repeated use of the fungicide which exerts selection pressure on the population. The fungicide selectively inhibits sensitive strains, but allows the increase of resistant strains.”⁷² Same story, different organism. This process can happen astonishingly quick in fungi, as exhibited by Cercospora sojina, a fungus that causes frogeye leaf spot on soybean. Nebraska University has found that over 1.5 trillion Cercospora sojina conidia (reproductive spores) are produced from a 40-acre soybean field heavily infested with frogeye leaf spot, assuming there are 5 million or more soybean plants in the average 40-acre field. This results in 15,000 mutant isolates in a heavily infested 40-acre field.⁷³ Imagine how many mutant isolates are created during a county-wide outbreak spanning thousands of acres! My educated guess would be millions of mutants in one growing season, each with varying rates of resistance. The actual method of defense that fungi utilize to protect themselves against fungicides also varies. Recognized modes of defense include increased activity of efflux pumps, metabolic circumvention, detoxification, standing genetic variations and regulation of stress response pathways.⁷⁴In other words, fungi are quick, they’re shifty and continuing our chemical arms race with them might not be the wisest strategy moving forward, especially with the decline in introduction rate of new fungicides.⁷⁵

One unintended consequence of encouraging fungal retaliation is that resistance appears to spill over into the world of human health. Matthew Fisher of the MRC Centre for Global Infectious Disease Outbreak Analysis at Imperial College London and a team of experts write that, “The intimate relationship between environmental populations of fungi and ensuing exposures to antifungals means that emerging environmental resistance is likely to affect the clinical management of fungal infections… [A]s with licensed medical antifungals, agricultural fungicides used in agriculture have broad-spectrum activity across the fungal kingdom. As such, resistance arises not only in the crop pathogens per se but also in other environmental fungi that include potential human fungal pathogens.”⁷⁶ One such example is the link between azole fungicide application and the rising rates of azole-resistant Aspergillus fumigatus infections in humans.⁷⁷ Part of the issue is their lipophilic (fat-loving) nature, which makes the chemical structure of azoles highly stable in a soil. This means that they can maintain their antifungal properties in the environment and in food for months.^78,79 All of this should serve as a stark reminder that our attempt to sterilize fungi with industrial chemicals impacts more than just agriculture.

Last but not least, many plant species are now resistant to the herbicides that producers apply to wipe them out. This should come as no surprise because plants are arguably Earth’s greatest organic chemists, producing thousands of complex compounds that help them communicate with their neighbors, defend themselves and entice animals to spread their seed.⁸⁰ What they lack in movement, they make up for in chemical wizardry, so attempting to cut them off at the knees with industrial chemicals is only playing to their strength. The numbers back this up. In 2021, the University of Minnesota wrote that, “By 1991, 120 weed biotypes were resistant to triazine herbicides and 15 other herbicide families were documented throughout the world. Since then, nearly 500 unique cases of herbicide resistance have been reported.”⁸¹ 2024 data from the International Herbicide-Resistant Weed Database reports that there are currently “530 unique cases (species x site of action) of herbicide resistant weeds globally, with 272 species (155 dicots and 117 monocots). Weeds have evolved resistance to 21 of the 31 known herbicide sites of action and to 168 different herbicides. Herbicide resistant weeds have been reported in 100 crops in 72 countries.”⁸²Among them, many of the most economically damaging weeds have developed resistance to glyphosate, the most sprayed active ingredient on the planet. These include Palmer amaranth, tall waterhemp (Amaranthus rudis), common ragweed (Ambrosia artemisiifolia), giant ragweed (Ambrosia trifida), hairy fleabane (Conyza bonariensis), horseweed (Conyza canadensis), burningbush, Italian ryegrass (Lolium multiflorum), annual bluegrass (Poa annua), and johnsongrass (Sorghum halepense).

The process of herbicide resistance is similar to all the other processes of resistance we’ve encountered so far. Herbicide resistance occurs because, “Each time the herbicide is applied, susceptible plants die and those with resistance survive.”⁸³ As Robert Battel of Michigan State University writes, “It’s “survival of the fittest” in fast forward.”⁸⁴ Even worse is that herbicide-resistant genes don’t disappear from the genome (total gene pool) of weeds even after a herbicide is taken off the market. Plants, as well as microbes and animals, carry resistant genes with them for generations like a scar from a battle wound. This is an important fact for two reasons. First, plants have been using chemical warfare for millennia, so some of them may have a resistant gene tucked away in their genome that helps them evade a “novel” herbicide. Continued application of a herbicide creates the pressure that causes this ancient gene to express itself, save the plant from death and grow in the population, making the herbicide less effective over time. Second, the ability to hold onto genetic traits for generations means an ineffective herbicide is potentially taken out of our arsenal forever.”⁸⁵

Losing herbicides is a threat to global food supplies, especially as chemical companies are struggling to bring new herbicides to the market. In a 2024 article titled, ” Crop-killing weeds advance across US farmland as chemicals lose effectiveness“, journalists Rod Nickel and Tom Polansek of Reuters interviewed two dozen farmers, scientists, weed specialists and company executives and reviewed eight academic papers published since 2021 to learn more about the threat of herbicide resistance. Bob Reiter, head of research and development for Bayer’s crop science division, told Nickel and Polansek that, “We’re really desperate for (new modes of action) if we’re going to sustain uses for farmers. Two decades ago, companies commercialized a product for every 50,000 candidates, but it now takes 100,000 to 150,000 attempts.” Part of the issue appears to be increasingly stringent environmental testing required for each new product, increasing the amount of time and money required to bring a product to the market. As a result, “Over the last two decades, chemical companies have reduced the share of revenue devoted to research and development spending and are introducing fewer products, according to AgbioInvestor, a UK-based firm that analyzes the crop protection sector.” The amount of time and money to develop a new herbicide is simply becoming too much for company executives to justify the efforts. Despite this, there are some encouraging signs for the industry as “FMC plans the 2026 launch of an herbicide to kill grassy weeds in rice crops based on the industry’s first new mode of action, a term for the way a chemical kills a weed, in three decades. The herbicide was in development for 11 years.” Even so, the challenges detailed in Nickel and Polansek’s article should question whether playing chemical catch-up with herbicides is the right direction weed management should take in the first place.

The closing of the article is a fitting end to this section on sterilization in agriculture and its negative effects on succession: “Bill Freese, scientific director of the Center for Food Safety in Washington, said farmers should shift away from crops genetically engineered to tolerate herbicides, which lead to plants becoming resistant to multiple chemicals through repeated sprayings. “It’s like this toxic spiral,” Freese said. “There’s no end in sight.””⁸⁶

Hopefully this discussion on the consequences of a sterilizing approach to health in both both healthcare and agriculture gives you a better perspective of why many proponents of regenerative agriculture view pesticides as tools to be used toward the end of the treatment process, not the beginning. In an ideal world, we’d never use these products, but farming and ranching is extremely difficult and nature can be a cruel mistress sometimes. Therefore, these products have their time and place, just like life-saving antimicrobial drugs have their time and place. The issue is that agricultural production methods have so diminished ecosystem functioning that farmers and ranchers are now reliant on them to produce a reliable harvest year after year. Like a human on a life-support system or someone reliant on a chemical compound such as caffeine or alcohol, quitting cold turkey is likely to be the wrong approach. Most production sites need to go through a weaning period before alternative methods of protection can be utilized. We will have a worldwide disaster if everyone decides to stop using pesticides cold turkey or even too quickly, just like cold turkey abstainers of coffee or beer get caffeine headaches and experience alcohol withdrawal symptoms while their bodies readjust.

Resistance to chemical products is a spectrum and there are many great people working to inform us on how to use antimicrobial drugs and pesticides efficiently so their effectiveness is extended into the future. However, the fact remains that the current system’s reliance and overapplication of them does not regenerate life and ecosystem functioning. In many cases, the opposite effect is observed and the succession clock is reset to a place where r-strategy opportunists thrive. Chemical products have a place, but that place is fixed within a system that prioritizes a richness and diversity of life because that is where truly sustainable health and balance are found. Microbes, insects and weeds are simply too vast and too adaptable to ever fully control in our bodies and on the land.

Life to the Full

The previous section discussed the first of two methods utilized to create an ecosystem that is not susceptible to domination by pests, disease and weeds. That method can be summarized by one word: death. Hopefully by now you understand that this strategy is untenable in the natural world, even though most farmers and ranchers are taught to sterilize away the bad guys like they’re working in some sort of closed operating room. So, what’s a producer to do? It’s simple. Rather than killing our way to health, the best solution to many, if not most, of the laundry list of issues that agriculture faces today is to do a total 180° turn and promote as much life as we can. Only by implementing management systems that promote a rich diversity of life can agriculture reap the benefits of succession and efficiently manage our role in climate change, soil erosion, food prices at the supermarket, nutrient density of food, water quality, air quality, worker’s rights, animal welfare and rural development while ensuring producers make a livable wage. Creating and maintaining a diversity of living organisms on the farm and ranch ensures that there are appropriate checks and balances in the system that prevent domination by a few opportunistic organisms. In addition, each and every living organism on Earth brings a unique skill set to the table, meaning a wider range of ecosystem services are provided when species richness and diversity improves. Compare these positive compounding and cascading effects to the negative side effects listed during a pharmaceutical commercial or the skull and crossbones on the label of a pesticide, and you can see a clear contrast in the consequences of conventional and regenerative systems. In fact, encouraging as much life as possible is so fundamental to the ethos of regenerative agriculture that diversity is the only topic that is a Principle of Soil Health, a Rule of Adaptive Stewardship and an Ecosystem Process.

To illustrate this point, let’s return briefly to our discussion on C. diff . Recall that a wiped out gut microbiome is a major risk factor for developing an infection of this potentially deadly bacteria. With this in mind, medical professionals hypothesized that a speedy recovery from C. diff infection would be observed when a patient’s gut microbiome returned to a rich and diverse state. Lo and behold, the treatment worked and fecal microbiota transplantation (FMT), also known as stool transplantation, was borne out of this hypothesis. FMT, for those that don’t know, is a procedure in which stool from a healthy donor is placed into the gut of a patient in order to treat a certain disease. The healthy patient’s stool acts as an inoculant of healthy microbes, greatly speeding up the recovery of the patient’s gut microbiome to a healthy level. Put in the context of succession, FMT allows for a speedy return to a disease-resistant climax community. Incredibly, FMT has a cure rate of 80% to 90% with a single treatment and is now the standard procedure for preventing recurrent C. diff infections.⁸⁷ The results of FMT are almost unbelievable, but it makes total sense inside the broader discussion of succession and ecology. That’s the power of working with nature and not against it!

C. diff’s r-strategist tendencies and FMT’s success may seem too-good-to-be-true, but it’s actually the way the natural world operates. Richness and diversity of species naturally bring about health and balance. Life is pretty simple in that way, and land managers have a lot to gain by prioritizing richness and diversity in the agricultural ecosystems they take care of. Earlier sections discussed the problems that arise when microbial, insect and plant communities are disturbed, so let’s now look at the potential benefits when we build them up, starting with the microbiome in the soil.

Underneath our feet is an eternal battle raging between trillions of microbes as they collaborate and compete for precious resources. Grandpas worldwide might say they’re “old as dirt”, but this microbial war for space and food has truly been around since the genesis of dirt. (Soil for you purists out there!) The point is that this battle keeps populations of potentially harmful species in check and greatly reduces the risk of a few aggressive ones dominating resources to the detriment of all the others. Scientists even have a term for a soil with these qualities. They call it a disease suppressive soil, or DSS. How awesome is that? The soil is naturally suppressive of disease when the system is operating as it was designed. The key to it all is the biology. As one group of scientists write, “Maintaining a dynamic microbial balance between species, high soil microbial biomass, and high microbial diversity are key factors which facilitate the development of disease suppressive soil (DSS).”⁸⁸

So, how do they do it? How can tiny organisms possibly do a better job at suppressing disease outbreak than the powerful chemicals inside of pesticides that are back by billions of dollars of research and development? Not to sound like a broken record but it boils down to diversity. To understand this more fully, imagine yourself as a root pathogen in a rich, diverse soil environment. If you were to do this, you’d find yourself in a bustling metropolis of activity like nothing you’ve ever seen! Life is moving at incredibly fast speeds, and you soon discover that all kinds of organisms lurk around every corner that 1) make chemicals that will harm you, 2) are bigger than you and want to eat you, 3) are smaller than you and want to colonize you or 4) get in your way as you try to find food and shelter. You can see how difficult it would be for you and your family to find a susceptible plant root and multiply fast enough to do large-scale damage with this kind of competition. The microbial community is simply too numerous and too powerful for you to get a stranglehold on the situation. These are the direct and indirect methods in which soil microbes keep pathogens at bay. In scientific, smarty-pants terms, we would say that beneficial microbes inhibit soil pathogens through various modes of action, such as “antibiosis, parasitism, competition for resources, and predation.”⁸⁹ The diversity of methods is the true source of strength!⁹⁰ If one mode of action doesn’t keep a pathogen in line, something else likely will. As a result, pathogens are unable to become resistant to holistic biological suppression like they do with pesticides. There are simply too many modes of action for a microbe to change quickly enough to evade them all. To make matters worse for pathogens, beneficial microbes themselves have the ability to quickly shift and adapt to new pathogen strategies. Contrast this with pesticides whose chemical structures are the same, predictable pattern, making it easy for pathogens to sidestep it in the future. It’s no wonder that resistance to such products has become a widespread issue, especially because pesticides often only use one or two modes of action to control pathogens.

Rather than rely on chemicals, we should start fighting fire with fire and rely more on fellow members of the soil microbiome to do our bidding for us. To achieve disease-suppression levels, farmers and ranchers need to implement practices that promote organisms like actinomycetes⁹¹, azospirllum⁹², Pseudomonas fluorescens ⁹³ and the hundreds of other species that hinder plant pathogens through the production of antimicrobial compounds such as “siderophores (metal chelators), ß-1, 3-glucanase, chitinases (fungal cell walls are made of glucans and chitin), antibiotic, fluorescent pigment and cyanide”.⁹⁴

One point worth noting is that plants are active participants in designing a disease-suppressive soil microbiome. They are able to sense danger and exude chemical compounds that attract microbes to the rhizosphere to take care of dangerous microbes (and other pests like insects).⁹⁵One German study does an excellent job of detailing the interplay between plants and microbes to suppress pathogens, which in this case are disease-causing nematodes. Just to show how complicated these interactions are, here is the description from the authors: “We highlighted nematode biocontrol mechanisms, especially parasitism, induced systemic resistance, and volatile organic compounds using microbial consortia, or bacterial strains of the genera Pasteuria, Bacillus, Pseudomonas, Rhizobium, Streptomyces, Arthrobacter, and Variovorax, or fungal isolates of Pochonia, Dactylella, Nematophthora, Purpureocillium, Trichoderma, Hirsutella, Arthrobotrys, and Mortierella.”⁹⁶That’s a lot of moving parts, but it in all honesty it’s probably just a fraction of what’s going on down there! In fact, suppression of pathogens is only half of the story. Soil microbes also work hard to strengthen plants and make them less susceptible to a pathogen attack that got past the first lines of defense. They do this because roots and root exudates are the primary source of raw material and energy inputs into the soil, so it’s in the best interest of the soil microbiome to keep plants thriving and photosynthesizing efficiently. One well-studied group of microbes that aid plants are the “plant growth-promoting rhizobacteria” (PGPR). These bacteria can be found outside the root in the rhizosphere and in the plant root to provide protection from the inside.⁹⁷ PGPR provide many services that lead to healthier plants, such as the production of beneficial plant hormones like auxins, cytokinins, gibberellins, ethylene and abscisic acid. PGPR also promote healthy plants by activating plant immune system responses (a.k.a. induced resistance)⁹⁸, fixing nitrogen, solubilizing mineral phosphates and other nutrients for uptake and enhancing resistance to stresses like drought and high salt levels.⁹⁹

Each PGPR has its unique skill in suppressing pathogens and strengthening the plant, which is great, but research shows that their effectiveness and reliability increases dramatically when they work together. For example, only the co-inoculation of Pseudomonas fluorescens F113 and Stenotrophomonas maltophilia W81 protected sugar beet from Pythium-mediated damping-off in an Irish field experiment compared to individual inoculation.¹⁰⁰ Similarly, the co-inoculation of Pseudomonas fluorescens sp. M23 and Bacillus sp. MRF significantly decreased infection of Fusarium spp. in maize in comparison with untreated control plants and with a single bacterial agent treatment.¹⁰¹ Lastly, a field experiment in Thailand found that “the mixture of Bacillus amyloliquefaciens IN937a and B. pumilus IN937b elicited systemic resistance, leading to more consistent broad-spectrum pathogen control in various crops under field conditions in comparison with an individual strain.”¹⁰² If research shows improvements in plant health with the interaction of just two species of bacteria, just imagine the effectiveness of a rich, diverse soil microbiome with millions of species and trillions of viruses, bacteria, fungi, protozoa and nematodes all working in synchrony!

Speaking of fungi, just like there are PGPR, the soil is littered with various plant growth promoting fungi (PGPF).¹⁰³ Fungi were discussed earlier in the article for their essential role in building soil macroaggregates, so we already know one way in which they improve plant health and promote succession. Mycorrhizal fungi are especially important in this aggregate-building process, but these root-associating fungi do much more than just build soil. Mycorrhizal fungi also boost plant health by increasing the uptake of water and nutrients like phosphorus, nitrogen and zinc, while also increasing a plant’s tolerance to adverse conditions such as drought, high temperatures, salinity, and acidity, or a build-up of toxic elements in the soil.¹⁰⁴. In addition, mycorrhizal fungi stimulate immune responses in the aboveground portions of plants and make them more resilient against pathogenic microbes or insect pests.¹⁰⁵ If that wasn’t enough, plants can utilize shared fungal networks to send warning signals to nearby plants so their neighbors can raise their defenses against an attack before it reaches them.¹⁰⁶ Many people call this connection the “wood wide web” due to its discovery and presence in forest climax communities.¹⁰⁷ Given all these benefits, it’s no wonder approximately 85 % (˜340,000 species) of all plant species are colonized by mycorrhizal fungi (˜50,000 species)!¹⁰⁸

As great as mycorrhizal fungi are, not all PGPF are mycorrhizal. Trichoderma are a genus of soil fungi found all over the planet that are a model example of non-mycorrhizal PGPF. These ubiquitous fungi are known to increase plant healthy by “improving plant growth and vigor and enhancing stress tolerance, active uptake of nutrients and bioremediation of contaminated rhizosphere, as well as providing plants several secondary metabolites, enzymes and plant regulating proteins.^109,110 The first image below is from Cornell University and shows the drastic improvement in root growth from sweet corn and soybean plants inoculated with a strain of Trichoderma fungus called T-22. The second image below was taken during my research at Purdue University studying the effects of T-22 on tomato plant disease resistance and production. Notice the difference in growth from the seedlings on the left that received a liquid inoculation with Trichoderma with the seedlings that did not .

Check out this article on Trichoderma from Cornell University for more detailed information on these superheroes in the soil.

In addition to bacteria and fungi, soil organisms like protozoa and nematodes benefit plant health primarily by cycling nutrients efficiently and controlling pathogen populations through predation. Viruses provide a similar service, except they operate through parasitism as non-living entities. By the way, if all the viruses on earth were laid end to end, they would stretch for 100 million light years¹¹², so they’re obviously providing useful services that keep the system moving along or we would all be in trouble in a hurry! To read more about the benefits of protozoa, nematodes and viruses, check out the previous article on the Nutrient Cycle. Lastly, even archaea, the most forgotten-about class of microbes, promote plant growth, adaptation to abiotic stresses, and immune activation.¹¹³ It’s truly incredible how collaborative the natural world is.

Alright, so a thriving microbiome keeps pathogens in check and helps to create healthier plants. The question now is how to build up a degraded microbiome and reap the rewards that diversity offers? The short answer is to follow the 6-3-4! The longer answer is to implement practices that create a diverse habitat to support a diverse population of microbes. Build diversity and diversity will come, essentially. All kinds of microbes exist in the soil and each of them thrive in varying conditions. For example, some microbes require oxygen and some really struggle in the presence of oxygen, such as nitrogen-fixing rhizobia or many beneficial actinomycetes. Some microbes are small and can fit in tight spaces, while others are quite large and need bigger structures to roam around and find their food. In a nutshell, we’re trying to create heterogeneity by forming a well-aggregated soil that contains aerobic sites, anaerobic sites, tiny sites for prey, even tinier sites for organic matter to hide for decades, wide open sites for predators and hotspots of nutrient and water availability. This is the type of heterogeneity we’re looking for, but it requires proper soil structure!

The best way to encourage the formation of aggregates and heterogeneity is to allow the ecological system to do the work. Soil ecosystems will naturally self-organize, self-heal and self-regulate into increasingly efficient systems when they’re given the right conditions. I encourage readers to dig into a nearby fenceline (assuming it hasn’t been mowed too often), grassland or woods to learn what the soil used to look like in your region. This is called your “ecological historical context” and it’s likely how your soil would look given the chance to heal itself. One of the best ways to start this healing process is to ensure there is a good home for the underground herd who will be doing the majority of the work. As it turns out, living roots create an extremely hospitable environment for soil biology, and the area immediately surrounding roots, called the rhizosphere, is considered one of the most complex ecosystems on earth.¹¹⁴ This flurry of biological activity sets in motion the soil building process. For example, roots and the mycorrhizal fungi work together to physically anchor the soil and glue soil particles together into macroaggregates.¹¹⁵ Therefore, step one to creating a soil that is fertile and abundantly productive is to get plants growing in the soil. No ifs, ands or buts about it. Once living roots are in the soil, disturbances like tillage and pesticide applications also need to be limited so the roots can establish themselves and the biology has time to work off of them. Chronic tillage, in particular, is harmful to the building of soil structure because it breaks apart macroaggregates and creates the homogeneous conditions that discourage diversity.¹¹⁶

As any good parent (hopefully) knows, it’s not enough to just house the living organisms under our care. We’ve also got to make sure they’re constantly fed, and microbes are no different. They require constant inputs of food to use as they live, grow and reproduce. Step one to feeding soil microbes on a large scale is to make sure living roots are in the soil for as many days of the year as possible. It’s déjà vu all over again! First and foremost, root exudates are a major source of food for microbes in the rhizosphere.¹¹⁷ Yes, these organic compounds are strategically released by plants to recruit certain beneficial microbes¹¹⁸, but it’s also believed that the majority of root exudates are passively lost from the root.¹¹⁹ Regardless of how they got there, microbes happily consume all shapes and varieties of exudates, which includes “low molecular weight primary metabolites (especially sugars, amino acids and organic acids) and secondary metabolites (phenols, flavonoids and terpenoids)”¹²⁰ Soil microbes also rely on plant roots themselves as a direct source of food. Decomposing microbes (a.k.a. saprophytes) happily feast on roots as they are dead and dying, whether it be short-lived root hairs or sloughed off root cap cells.¹²¹ An added bonus to saprophytic feeding is that underground decomposed material is turned into soil organic matter much more efficiently than decomposed aboveground residue.¹²²

Drastic management changes like utilizing cover crops and minimizing tillage should be done at the appropriate pace. What is “appropriate” differs on each farm and ranch based on differences in context, such as climate, social pressures and financial constraints. Whatever pace you decide to take, don’t expect changes to happen overnight. Ecological degradation of a field or pasture didn’t take a year to happen and neither will the recovery. That’s not meant to discourage you, but it’s a reminder that these things take time. Even so, producers often see major improvements in soil structure when given a few years of little to no disturbances and consistent inputs of food into the soil system, which is almost unbelievable when compared to geological timescales that think nothing of a thousand years. For us to positively influence soil structure in our lifetime and move along the succession timeline, we’ve got to create a soil that works on biological timescales. Getting living roots in the soil is the best way to kickstart that transition. The initial improvements brought about by living roots sets off a chain of positive feedback loops similar to those found in thriving climax communities. As the soil begins to self-regulate into macroaggregates, microbiome richness and diversity increases¹²³, which leads to an increase in plant health and diversity, which in turn significantly increases bacterial and fungal biomass.¹²⁴ Farming and ranching becomes really fun when biology is truly in the driver seat because the system is able to produce abundantly and improve itself while doing so.

Aside from the gold standard of living roots, another useful way to feed soil microbes is to add external amendments like compost. Compost is made up of organic matter in various stage of decomposition and the microbes that have already begun to decompose it, which makes it agriculture’s version of a probtiotic and prebiotic rolled into one! In essence, properly made compost provides a fresh regimen of beneficial soil dwellers, especially fungi and prokaryotic organisms (bacteria and archaea), as well as the food and shelter they need to help them survive in their new environment.¹²⁵ Consequently, compost has been shown to improve crop productivity ¹²⁶ and build disease suppression in the soil as a result of its application. ¹²⁷ My own research project yielded similar results as the the survival rates of Trichoderma T-22 organisms increased significantly when applied to plots amended with a fungi-rich deciduous leaf-based compost in the field. In addition, tomato plants that received the compost and Trichoderma inoculation exhibited fewer foliar disease symptoms and produced significantly higher tomato fruit yields.¹²⁸

Adding a layer of compost to a soil is a feasible option for many small-acre fruit and vegetable farmers, but it becomes much more challenging for large-acre row-crop farmers. Instead, many large-acre farmers are making liquid inoculants called “compost tea extracts” that are made by running compost through a straining process. Applications of compost tea extracts don’t necessarily provide food for soil microbes, but they are taking advantage of the compost by applying the beneficial microbes inside of the compost directly onto their crops. This is exactly like a person taking a probiotic to introduce beneficial microbes in their gut. One method of composting that is gaining traction among row-crop farmers is the Johnson-Su composting method due to its ability to produce a compost product rich in fungi, a result that is difficult to achieve with frequently turned, conventional composting. Check out in this webpage from Red Young Angus, a farming and ranching operation in Kansas, to see how they make Johnson-Su compost and learn how its addition to the soil has become “one of the biggest breakthroughs in improving soil health at Young and Son (farming entity of Young Red Angus)”.

What about composted plant material that drops out of the rear end of an animal? Not many people think of manure as compost but that’s essentially what it is. Think about a grazing cow that consumes a mature plant in the pasture. The digestive system of the cow and the microbiome contained within it break down that plant material and transform it into a beneficial soil amendment in a matter of days. This is a lightning fast cycling of nutrients back into the soil ecosystem compared to the months it would take for a standing plant to degrade on its own. Adding insult to injury, plants left standing will return fewer nutrients to the soil ecosystem because much of the nutrition will oxidize away by the time the plant hits the soil surface. Oxidized plant material may be a decent source of carbon, but that’s about all the soil is getting back.

Manure is also an excellent source of beneficial microbes and organic matter to feed soil organisms. An incredible 18-year studying examining the application of pig manure found that manure application significantly enhanced soil bacterial diversity and the relative abundance of saprotrophic fungi which was observed to suppress plant pathogens and parasites.¹²⁹ Another study found that manure treatments significantly increased the proportion of soil macroaggregate fraction under the high level manure treatments compared with low manure and no manure treatments. As a result, the total number of nematodes increased significantly, which directly benefited carbon cycling in the soil primarily by grazing local bacteria.¹³⁰ So, what we really have in manure is an organically produced fertilizer/probiotic/prebiotic/Fecal Microbiota Transplant soil amendment that helps build the house for soil microbes and also feed them. What can’t poo do?

Now that we’ve examined how diversity in the soil promotes health and wellness, it begs the question: does the same pattern reveal itself aboveground? Specifically, do regenerative practices encourage succession through plant and insect species diversity and, if so, what kind of benefits can producers expect? Let’s answer these question by breaking it down into grazing and cropping sections. We’ll start with livestock operations that utilize adaptive multi-paddock (AMP) grazing techniques and finish with cropping systems that prioritize regenerative practices like cover cropping and reduced tillage.

Succession on the Ranch

Grazing is not grazing is not grazing. Animal impact on the land can have either a positive or negative effect on the landscape depending on how the livestock are managed. The fascinating part is that commons sense tells us that “stupid” animals need “wise” human guidance to be effective tools in creating healthy landscapes, but, quite honestly, the opposite is closer to the truth. Migrating herbivores of centuries past enhanced ecosystem functioning and promoted succession of the landscape. They created ecosystems that made the efficient use of resources a competitive advantage, rather than the ability to scavenge for resources in a derelict environment, like that found in early succession landscapes. As a result, the first humans to inhabit nearly every virgin landscape found a diverse, rich and abundant ecosystem teeming with plant and animal activity. Adaptive multi-paddock (AMP) grazing is a system of management that mimics the natural migration patterns of herbivores for the purpose of regenerating and recreating the fertile landscapes our forefathers once inherited. Check out the articles on the three rules of adaptive stewardship (compounding, disruption and diversity) to get more of the nitty-gritty details on AMP grazing. For now, we can just say that AMP grazing mimics natural grazing patterns not based on the amount of animals, but based on the amount of time animals are allowed to graze a specific area of land. The secret ingredient that really separates conventional grazing from AMP grazing is recovery and rest. Plants need time to recover after being ripped in half by an animal after all! With AMP grazing, livestock are moved out of a paddock once they’ve grazed an area to the desired height (which should be roughly no more than 50% for optimal long-term pasture performance). They are not allowed access to that parcel of land for a period of time to let the forage regrow. The time between grazing events depends on a variety of factors, such as the time of year, visual evidence of regrowth and demands of the animals. It’s not called “Adaptive” for nothing! The take-home message is that pastures naturally grow stronger and more diverse over time when plants are allowed to recover. Even better results are achieved when rest is accompanied on top of recovery.

By prioritizing recovery and rest, AMP graziers are allowing their forage to improve at the speed of nature. One input that often becomes useless after implementing AMP grazing is fertilizer. Yes, fertilizers green up a pasture and promise a shortcut to production, but there’s a very high probability that it’s doing more harm than good. Speaking specifically about nitrogen fertilizer, professors Brady and Weil describe the unintended consequences of its application in their textbook, The Nature and Property of Soils. They write, “Natural rangeland ecosystems contain a wide variety of native plant species that are known for their ability to conserve nitrogen and efficiently utilize low levels of deposited nitrogen (2–5 kg N/ha/yr). However, research using deliberate nitrogen additions suggests that as nitrogen deposition increases, certain plants—often exotic species—that are highly responsive to high levels of nitrogen quickly crowd out many of the desirable native species that are adapted to grow efficiently at low nitrogen levels. Attempts that have been made to increase rangeland productivity by adding fertilizer nitrogen may increase productivity temporarily, but again, the low-nitrogen-requiring native species are soon crowded out and replaced by high-nitrogen-requiring exotic species that are generally considered weeds. The resulting systems are lower in biological diversity and productivity than the original native rangelands.” (Brady and Weil pg. 612 https://www.amazon.com/Nature-Properties-Soils-15th/dp/0133254488) Therefore, one of the most effective questions to ask ourselves is, “What do I want my pastures and my forage to look like?” This little exercise is essential for two reasons. First, it requires the grazier to picture an ideal pasture for grazing. Once this is done, having a visualized goal allows management decisions to become more obvious over time. Just like a GPS demands a destination to give a route, we have to have a target to aim at in order to confidently know the path forward. Another popular way of saying it is “managing for what you want”. Always ask “What do I want?” and follow up with “How do I get there?” Remember, if you fail to plan, you plan to fail. Alright, enough cliches. The rest of this section is filled with information illustrating why graziers should aim for a pasture that mimics natural climax communities full of plant and insect diversity and why AMP grazing is the ideal route to get to that (now) desired destination.

The first reason to manage for diverse grazing land is that plant species diversity and diversity within each functional group (grasses, forbs, legumes, woody species) increases aboveground community biomass production. (https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/09-0069.1) (https://www.nature.com/articles/379718a00)(https://www.nature.com/articles/srep44641) That’s quite the mouthful. Essentially, more types and species of plants will produce more plant material than fewer types and species of plants. One meta-analysis found an average of 1.43 times more plant material in the most diverse polycultures compared to the average monoculture. (https://bsapubs.onlinelibrary.wiley.com/doi/10.3732/ajb.1000364) A 9 year study from Penn State University found similar results when comparing a two-species mix to a five-species mix over a nine year period. When averaged across years, the five-species mixture produced 31% more forage biomass than the two-species mixture, and the difference between mixtures tended to be greater in wet than in dry summers. (https://acsess.onlinelibrary.wiley.com/doi/10.2135/cropsci2015.11.0711) The study also found the five-way mix increased soil carbon levels faster in the top 100 cm depth compared to the two-way mix: 1.80 Mg ha⁻¹ yr⁻¹ for the five-way mix compared to 0.50 Mg ha⁻¹ yr⁻¹ for the two-way mix. This increase in soil carbon indicates a subsequent increase in organic matter, which is key to improving overall ecosystem functioning and services. (https://www.nature.com/articles/s41559-017-0395-0) While these results are encouraging, research dedicated to the effects of AMP grazing are showing even more promising results for pasture diversity and productivity. The following are a few such results:

This analysis suggested the reference natural areas (RNAs) were by far more diverse with more species sharing the Importance Value. It also suggests conventionally grazed (CG) ranches were the least diverse and that AMP ranches were transitioning (“diverging”) toward a higher dominance diversity condition, away from the CG plant community. (https://carboncowboys.org/images/published_research/pdfs/apfelbaum-veg_infitration_carbon_2022.pdf)
- Standing crop biomass was >300% higher on AMP ranches compared to conventionally grazed (CG) ranches. (https://carboncowboys.org/images/published_research/pdfs/apfelbaum-veg_infitration_carbon_2022.pdf)
On average, the AMP ranch had 1.5 more species per grid than the CG ranch, with the maximum richness of six, as compared to four in the CG ranch. (Meaning that AMP encourages diversity and mixing of species in close proximity, while CG grazing encourages big clumps of homogenous species.) (https://link.springer.com/article/10.1007/s10980-021-01273-z)
AMP grazing systems outperformed CG systems by generating: (a) 92.68 g m² more standing crop biomass (SCB), promoting 46% higher pasture photosynthetic capacity, while observing a 19.52% reduction in soil C (CO₂) respiration rates. (https://peerj.com/articles/13750/)
Net above ground primary production (NAPP) was nearly three times higher in muli-paddock (MP) pastures than in conventionally managed (CM) pastures and seven times higher than in hayfields at the time of sampling. (https://www.tandfonline.com/doi/abs/10.1080/21683565.2019.1591564)

Finally, my favorites, which shows direct connections between regenerative AMP grazing, ecosystem functioning and succession:

Our review revealed that biodiversity, nitrogen cycling, and carbon storage in regenerative grazing systems more closely resemble wild grazing ecosystems than do conventional grazing systems. (https://www.frontiersin.org/articles/10.3389/fsufs.2022.945514/full)

Diversity and production are great results in and of themselves ecologically speaking, but the great news is that the ripple effect of a regenerated pasture is also staggering from a business standpoint. Financial research is difficult and quite scant at the moment, but initial findings indicate drastic increases in forage production from AMP grazing provides a direct avenue to increase livestock numbers sustainably and increase profitability.

Multi-paddock (MP) grazing excels in that it can sustain much higher stocking density without a negative influence on the biomass and composition of grass. (https://www.sciencedirect.com/science/article/abs/pii/S1550742416300495)
AMP managed systems provided sufficient forage biomass to support grazer stocking densities 2.38 times higher than conventional grazing systems, while also promoting development of soil food web structure, diversity and functionality and collectively making AMP systems more ecologically resilient, sustainable and profitable. (https://peerj.com/articles/13750/)
Simulations show that shorter periods of grazing increase both ecological condition (EC) and profitability while increasing recovery periods increases both EC and profitability initially but profitability decreases if recovery periods are too long. Both EC and profitability are positively related to number of paddocks used. (https://pubmed.ncbi.nlm.nih.gov/25527985/)
“Plant diversity substantially increased quality-adjusted yield and
revenues.
These findings hold for a wide range of management intensities, i.e.,
fertilization levels and cutting frequencies, in semi-natural
grasslands. (https://www.nature.com/articles/s41467-020-14541-4)

Another benefit from increasing diversity of plant species that is often overlooked relates to the increase in nutrition it offers to livestock. As humans, we’re told to “eat the rainbow for good health” because specific colors are caused by specific compounds, such as the anthocyanins that give blueberries their blue hue. Therefore, a diversity of colors on our plates indicates that we will ingest a diversity of health-promoting nutrients. If that’s the case with us, why wouldn’t it be the case with animals? The fact is that it’s absolutely the case, and diverse pastures are part-restaurant, part-pharmacy environments that lets an animal select for forage containing the nutrients they require at that moment in time. Dr. Fred Provenza of Utah State University describes this as allowing animals to express their “nutritional wisdom”. I encourage everyone to read his masterpiece Nourishment to learn more about nutritional wisdom of livestock and humans. Inside, you’ll find a satisfying mixture of decades of research and old-world wisdom that depicts how livestock are capable of self-medicating when given the chance. A diverse pasture is not only composed of a mix of macronutrients (carbohydrates, fats and proteins) but it also means there are a plethora of plant secondary and tertiary compounds. Secondary and tertiary compounds are produced by plants as mechanisms to survive stress in their environment and they are generally involved in processes that improve health and wellness of the plant rather than direct growth and development. Fortunately, many of these compounds are beneficial to us and livestock when they are consumed. Terpenes, tannins, glycosides and flavonoids are a few common examples. Benefits of plant secondary and tertiary compounds for livestock include antiparasitic effects (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9924796/), antioxidant effects (https://www.sciencedirect.com/science/article/abs/pii/S0378874121004736) and increased protein and energy efficiency. (https://sanangelo.tamu.edu/people/research/dan-quadros/psc-livest/) Another little-known benefit of diversity is that nutrients combine in the bodies of living organisms. (https://onlinelibrary.wiley.com/doi/abs/10.1002/jsfa.5643) Reductionist nutrition research really struggles to uncover these synergies, such as One example is the ability for Cancelling out of tannins by alkaloids (Provenza), but they certainly exists. We tend to study nutrition in silos. It’s very hard to
understand how nutrients interact with one another. Animals that have
the ingredients separated out are healthier, so when they have choices
in the field, their body wisdom will guide them to make healthy eating
decisions. Don’t know which plants contain these compounds? This is yet another reason to manage for a diverse pasture and hedge your bets! George Strait said “I ain’t here for a long time, I’m here for a good time“, but given the appropriate choice of nutrients AND secondary/tertiary compounds, he could be here for a long time and have a good time! Same with livestock.

The next reason to move toward a diverse pasture is that it extends the growing season dramatically. Given that the majority of grazing costs are incurred with winter feeding, this should capture every grazier’s attention. The trouble with monoculture pastures is that they have a very defined peak growing season with exclusively vegetative forage in beginning and plants trying to express their reproductive genes toward the end. Outside of that narrow range of activity, there’s not much growth happening. However, diverse pastures offer livestock a variety of plants at various stages of growth throughout the year, which gives them more choice and a more balanced diet with each bite. They learn to eat a much wider variety of plant species. This helps improve their own health status and body condition, but also teaches the offspring to be less picky and to eat as their mothers do. Third, we expand the palate of our livestock. Nutrition of “weeds”. Include trees and woodies that bring up minerals from down deep, like Boron in Willow leaves. One group of ranchers in Western Canada reported that AMP grazing allowed them to graze significantly earlier in the year, with a mean initiation date of grazing of April 25, as compared with May 17 for non-AMP operations. Notably, four AMP operations reported “year-round” grazing (in Canada!). Not surprisingly, the total length of grazing was 54% longer (at nearly 7 months) on ranches using AMP grazing, even after the adjustment for dormant season grazing. (https://www.sciencedirect.com/science/article/abs/pii/S1550742421000531) Of course, this is anecdotal but it certainly lines up with the narrative.

These studies show that the land needs animals pulsing the land to encourage the latent seed bank to germinate.

Diversity and Succession in plant species/weed suppression/soil conditioning:

Perennial plants are more resilient individually. More drought tolerant pastures. Individual forage is more nutrient-dense. Diverse pastures are more nutrient-dense for livestock. It turns out that the amount of root exudates increased significantly with increasing plant diversity, while exudate diversity did not. (Eisenhauer et al., 2017)

AMP grazing systems outperformed CG systems by generating: (a) 92.68 g m−2 more standing crop biomass (SCB), promoting 46% higher pasture photosynthetic capacity; (b) a strong positive linear relationship of SCB with fungal biomass and fungal to bacterial (F:B) biomass ratio. (Johnson et al., 2022)
Total microbial biomass was, on average, 1.3 and 2.0 times higher in soils from multi-paddock pastures than in soils from conventionally managed
pastures and hayfields, respectively. Relative fungal biomass in MP soils was 1.4 times higher than in CM soils and 1.7 times higher than in hayfield soils. (Kleppel, 2019) Mean arbuscular mycorrhizal and protozoan biomasses in CM and hayfield samples were about 10% of those in MP soils. Rhizobia were undetectable in 80% of the samples from CM pastures and 57% of the samples from hayfields. (Kleppel, 2019)
Fungal biomass increased most with increasing plant diversity resulting in a significant shift in the fungal-to-bacterial biomass ratio at high plant diversity. Fungal biomass increased significantly with plant diversity-induced increases in root biomass and the amount of root exudates. (Eisenhauer et al., 2017) We found that plant species diversity was about 70% greater in AM fungal inoculated plots, although some fungal species increased diversity up to 300% more than others by the end of the second growing season. Inoculation also significantly improved the diversity of late successional species. (Koziol & Bever, 2016)
As was mentioned earlier, soil fungi levels in the soil play a critical role in determining which plants grow best. When fungal levels are low, a typical characteristic of early succession landscapes, plants that don’t rely as much on them thrive. This is a common trait of r-strategist and annual plants. Later on, as fungal levels increase, plants that utilize their services are at a competitive advantage and make up more of the population. This is a common trait of k-strategist and perennial plants. Therefore, annual plants, with their living roots along with a reduction in soil disturbances, ameliorate the soil and improve conditions such that soil fungi begin to thrive. Soil fungi, and better ecosystem functioning overall, improve the soil further and allow perennials to thrive.
Livestock typically excrete 50-90% of the nutrients they are fed and fully-grown animals that are not gaining weight, gestating or producing milk or eggs excrete almost all of the nutrients they are fed.
(https://www.gov.mb.ca/agriculture/environment/nutrient-management/pubs/properties-of-manure.pdf) Remember, most of the nutrients a plant uptakes run through the body of a microbe first, so a more accurate way to think about the process is that manure and urine feed the microbes first who then feed the plant.

Diversity of grazing animals benefits: “may be one of the most biologically and economically viable systems available to producers, especially on landscapes that support heterogeneous plant communities.” Differing feeding patterns. “Defecation patterns affect nutrient cycling and plant–animal nutrition, note Anderson et al. (2012), and “although cattle prefer not to graze around their dung, sheep have been reported to graze around cattle dung, thus increasing the utilization of pasture” (https://www.researchgate.net/publication/231959800_Managing_livestock_using_animal_behavior_Mixed-species_stocking_and_flerds)

Diversity and Succession in insects: Invertebrates:
- High stocking densities, frequent rotational grazing and elimination of prophylactic ivermectin use resulted in greater insect species richness, diversity, predator species abundance, and dung beetle abundance than more conventionally managed rangelands. (Pecenka & Lundgren, 2019)
- This analysis suggested the reference natural areas (RNAs) were by far more diverse with more species sharing the Importance Value. It also suggests CG ranches were the least diverse and that AMP ranches were transitioning (“diverging”) toward a higher dominance diversity condition, away from the CG plant community. (Apfelbaum et al., 2022)
- Our study shows that high plant diversity can contribute to a faster transition of insect populations towards naturally occurring community assemblages and at later stages to more stabilized assemblages. (Lange et al., 2023)
- Rainbow dung beetle video (https://www.youtube.com/watch?v=m7iGsecbAZA&t=93s)
Invertebrate biomass, diversity, and abundance in the soil, on the soil surface, and in the vegetation were positively affected by regenerative practices in all three study systems (cornfields of the Upper Midwest, almond orchards of California, and rangeland systems of the Northern Plains) (Fenster et al., 2021)
This research suggests that it is not the number or abundance of species within a community, but rather the balance of species within these communities that contributes to pest suppression in maize fields. This confirms the importance of community evenness in pest suppression (Crowder et al., 2010) and suggests that species diversity of the entire community [not just higher trophic levels (Letourneau et al, 2009)] may contribute to pest suppression within realistic arthropod communities. (Lundgren & Fausti, 2015) The authors highlighted the ability of proactively designing a pest-resilient food systems to outperform a system that react to pests chemically. Soil fungi that control insect pests
(https://extension.psu.edu/managing-a-beneficial-soil-fungus-for-insect-control). Fungal endophytes protect the plant.
(https://www.sciencedirect.com/science/article/abs/pii/S1878818119305869)

Healthy plants with strong, healthy roots are darn near impenetrable. You’re forced to make spores and go into dormancy until the conditions are right for roots to be colonized. This could be when roots die or when roots become sick and need culling. Now, we’re using succession to our advantage by having microbes take out the weak and leave the strong to reproduce.

Higher animal diversity: Holistic Resource Management pastures had 1.5 times higher average abundances of obligate grassland birds than minimally rotated pastures and 4.5 times more obligate grassland birds than continuously grazed pastures. (Cassidy & Kleppel, 2017)

“These insects and other macro-organisms do a tremendous job of starting the plant litter degradation process required to turn it into new soil. They are also important to a thriving ecosystem. More insects attract more predators in the form of spiders, birds and other species. On farms and ranches that have implemented good adaptive grazing practices, I have witnessed an explosion of bird populations, from ground nesting birds to migratory birds, to songbirds.” (Diversity UA article)

“Overall, the conversion of forest to monoculture plantations decreased soil quality and the abundance of K-strategists, retarded the decomposition of persistent organic matter, but boosted the prevalence of r-strategists in a more diverse fungal community.” (https://www.sciencedirect.com/science/article/abs/pii/S0341816222005707)

https://understandingag.com/the-principle-of-diversity/

“The multitude of benefits derived from a far greater array of plant species creates greater microbial species diversity, significantly more secondary and tertiary plant compounds, attracts more insects, pollinators, birds, and other wildlife, and extends our grazing season. What’s not to like about this?” (Diversity UA article)

To summarize pioneer species = r-strategist = annual plants/pathogens/pest insects. K-strategists = perennial plants/beneficial microbes and insects that keep pests at bay.

Succession on the Farm

“Instead of getting it’s nutrients from the soil, the lichen extracts nutrients out of rain droplets running off the land, and out of the rock on which it sits. In this process the lichen will start to break down the rock, and some parts of the lichen may die and start to decompose. Slowly, very slowly, this process of pioneer species growing, spreading and dying will occur, often over the space of hundreds of years. Throughout this the bare rock is reduced to many smaller rocks with very old decomposed plant litter scattered about, i.e. a very basic soil.” “If nature is constantly going along this process from bare rock to mature forests, why isn’t the whole planet covered in these forests? That’s because the natural world is not stable. Whilst over time plant
communities dutifully march along the process of succession, every now and then they get knocked back.” Agriculture is difficult. How do we minimize these knocking back events while still providing food for ourselves?

This is exactly evidenced in our results of multiple cropping (MC) farms of Design B and C, in which the overall per plant productivity of the crops is more than five times higher than that of single cropping (SC) farms. (Deb, 2021)

Obtaining a perennial-based landscape is much, much more difficult in annual agriculture. Can we plant crops that are increasingly adapted to our soil type, rainfall, microbiome, temperatures, daylight, etc.? Can we create increasingly genetically resilient crops? Epigenetics through seed saving! Nutrient density and epigenetic effects of perennials/seed saving/context capitalizing. What if a farmer used insects and pathogens to take out the weaker plants and collect seed from the ones that survived? Think about the genetic strengthening process that occurs. This is how nature was designed to proceed.

Annual agriculture is difficult because weeds are annuals as well. We hit the reset button on succession every year and weeds spring into action to set succession into motion and we think they’re the bad guys. Now we really know why “The basic reason for the high incidence of soil-borne diseases in croplands is the deterioration of the soil micro-ecological environment that often disrupts the soil microbial community balance.” (Mazzola 2007)(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953945/) They get ripped and torn when tillage equipment runs through a field or pasture.

Comparison of eight neighboring farms across the United States found that regenerative farms had 3% to 12% soil organic matter (mean = 6.3%), whereas those on conventional farms had 2% to 5% (mean = 3.5%). (Montgomery et al., 2022)

“Recent meta-analyses demonstrate that intercropping can increase the land use efficiency of crop production by 20–30 % on average, indicating a strong potential contribution to sustainable intensification. Intercrop yields vary from much lower than sole crops to much higher across different studies.” (https://www.sciencedirect.com/science/article/pii/S03784290230011930) Be very careful if this approach is taken.

Creation of Weed Heaven. Think back to fungal-to-bacterial ratios. Mix all of those ingredients up and what do you get? What I call “weed heaven.” (I’m not talking about Colorado.) Bare, sterile fields give weeds, pathogens and economically damaging insects a competitive advantage. We’re creating the conditions that they do particularly well in compared to the rest of their compatriots. It’s no different than c. diff running wild in a sterile gut microbiome environment. Diversity confers group resistance against solitary domination. Remember, it’s in everyone’s best interest for a host to be healthy and provide a good home for them. “Many conventionally tilled agricultural soils have a F:B ratio of 0.1 to 0.3 with soils that are high in nitrogen, low carbon, neutral pH, and with disturbed soil conditions which promotes weed production. Annual crops prefer lower F:B ratios and perennials prefer a higher F:B ratio (Lowenfels & Lewis, 2006).” (https://ohioline.osu.edu/factsheet/anr-37)

In contrast, fertilization with urea did not significantly alter the structure of soil microbial communities compared to the control but reduced network complexity and altered hub taxa. (https://www.frontiersin.org/articles/10.3389/fsoil.2022.749212/full) “Chemical fertilisers reduce the number of nutrient solubilising bacteria associated with the roots of wheat, according to new research.” (https://www.rothamsted.ac.uk/news/fertilisers-reduce-plant-beneficial-bacteria-found-around-roots)

Insects in a balanced ecosystem will be more useful as taking out healthy tissue, plant or otherwise. Maggots have been used to consume infected human tissue, while leaving healthy tissue unscathed.
(https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1524-475X.2012.00850.x; https://www.science.org/content/article/how-maggots-heal-wounds;
https://www.telegraph.co.uk/global-health/science-and-disease/maggots-sent-war-zones-government-clean-wounds-save-limbs/)

“There is good potential for biological control of several fruit pests if populations of predators and parasitoids are preserved and enhanced. For example, biological control of plant-eating mites is achieved in many fruit production systems by conserving predatory mites, as well as predacious beetles and bugs. To avoid killing natural enemies of mites, pesticides must be selected carefully. Two classes of insecticides that are highly toxic for mite predators are the pyrethroids and the carbamates.”
(https://www.canr.msu.edu/grapes/integrated_pest_management/natural-enemies-predators-parasites)

Livestock grazing on living roots (CC) is a wonderful way of improving soil health like that of a higher succession landscape and also getting more bang for your buck by getting money out of the cover crop.

Profit was twice as high in the regenerative almond orchards relative to their conventional counterparts. (Fenster et al., 2021) Management practices hypothesized to enhance yield and environmental performance were adopted by 20.9 million farmers in China in 452 counties from 2005-2015.The increased grain output and decreased nitrogen fertilizer use were equivalent to US$12.2 billion. (Cui et al., 2018)

Use targeted insecticides. The best practice is prevention. An ounce of prevention is worth a pound of treatment.

“The best herbicide is shade.” Cover the soil.

(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7755035/) “Monocultures are ideal fungal pathogen feeding and breeding grounds.” As Dr. Allen Williams of Understanding Ag says, fungal networks in the soil are like gauze Reduced fungal activity with tillage (https://www.sciencedirect.com/science/article/abs/pii/S0038071702000330).

Our research suggests that agronomic practices that promote high levels of arthropod diversity fundamentally require fewer agronomic inputs. For example, reducing tillage (Lehman et al., 2015, Kladivko, 2001), increasing vegetation diversity on farms [for example, lengthening crop rotations, including cover crops in rotations, intercropping, managing field margins (Letourneau, 2011)], and developing minimal-till organic agriculture (Bengtsson et al., 2005) should help increase biodiversity. (Lundgren & Fausti, 2015)

If you’re trying to exhaust your soil of weed seeds, good luck. Think back to Surtsey Island. Seeds were carried by wave currents, air currents and migrating animals. If this happens on a literal island in the middle of the water, how much more does this happen in an agricultural field by wildlife and forest, prairie, field edges and neighboring fields. (https://extension.oregonstate.edu/news/how-long-do-weed-seeds-survive-soil)

quorum sensing (https://www.youtube.com/watch?v=q2nWNZ-gixI)

“the diversity of arbuscular mycorrhizal fungi is strikingly low in arable sites compared with a woodland.”(https://www.nature.com/articles/28764)

Teamwork: The greatest benefits from companion plant intercropping were reported for maize, with yields 37% higher than those for non-weeded control
treatments.(https://www.sciencedirect.com/science/article/abs/pii/S0378429017300734)

Use annuals as biological primers in the road toward resilience and succession.

A common theme with pathogens and weeds. Colonizers are just doing their job. Swiss study found that inoculating soil with mycorrhizal fungi increased corn yields by 40% in fields ravaged with fungal pathogens. Adding mycorrhizals sped up the ecological succession process to where it naturally is: checks and balances. (https://phys.org/news/2023-11-inoculating-soil-mycorrhizal-fungi-yield.html

Whether you believe in human-induced climate change or the sixth mass extinction event (https://www.axios.com/2023/09/22/earth-sixth-mass-extinction-wildlife), good stewardship…

As if there weren’t enough reasons to increase diversity on our operations, changing environmental conditions affect plant root structures different, with …. Forb-only grassland was found to have the least amount of below-ground biomass, forb/grass even split had more and grass-only grassland had the most below-ground biomass. (https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2435.14345) This is important to remember as you may often hear regenerative educators say things like “Don’t sweat the weeds.” What we mean is that the term “weed” is subjective. Corn in a corn field is a cash crop, but corn in a soybean field is a weed. The only crime it committed was not being desirable, so it just depends on the context. We can learn from these forbs because the conditions are right for them to prosper.

Now, it’s important to know that forbs become a smaller and smaller proportion of plant population as landscapes progress along the succession pathway.

William Bateson, the man who coined the term ‘genetics’, said “We commonly think of animals and plants as matter, but they are really systems through which matter is continually passing.” discussing fungi, “A mycelial network is a map of a fungus’ recent history and is a helpful reminder that all life-forms are in fact processes, not things. The “you” of five years ago was made from different stuff than the “you” of today.

“A simple light ray similarly bends when it enters water (compared to a lifeguard running on the beach first and then diving in the water because they can run faster than swim), also minimizing the travel time to its destination! This is known in physics as Fermat’s principle, articulated in 1662, and it provides an alternative way of predicting the behavior of light rays. Remarkably, physicists have since discovered that all laws of classical physics can be mathematically reformulated in an analogous way: out of all ways that nature could choose to do something, it prefers the optimal way, which typically boils down to minimizing or maximizing some quantity. There are two mathematically equivalent ways of describing each physical law: either as the past causing the future, or as nature optimizing something. Although the second way usually isn’t taught in introductory physics courses because the math is tougher, I feel that it’s more elegant and profound. If a person is trying to optimize something (for example, their score in a game, their wealth or their happiness) we’ll naturally describe their pursuit of it as goal-oriented. So if nature itself is trying to optimize something, then no wonder that goal-oriented behavior can emerge: it was hardwired from the start, in the very laws of physics.” (Life 3.0 page 251)

Grazing operations have a distinct advantage compared to annual crop operations because they have the opportunity to build perennial ecosystems. Less

is that the reaction requires anaerobic conditions to proceed. Good soil aggregation provides anaerobic microsites in the soil for free-living Nitrogen fixers to produce bioavailable Nitrogen. (Legume plants create this low oxygen environment inside of their swollen root hairs we call nodules.) Practices like tillage discourage free-living Nitrogen fixation because it physically breaks open soil aggregates and infuses large quantities of oxygen into the soil very quickly. As tilled soils lose their organic matter and ability to form aggregates, farmers and ranchers lose the service of having Nitrogen fixed for free, so they need to purchase expensive fertilizer to make up for a slowing down of biological activity.

Organic matter content in the soil is also negatively affected over time by tillage.⁹ Packs of hungry microbes are constantly on the hunt for cellular building material and energy, a.k.a. food! These microbial packs devour any organic material in their path, such as stubble in a field after harvest. This is all well and good as it’s part of natural nutrient cycling process. However, tillage physically breaks apart soil structure and exposes much more organic matter to microbes that was previously hidden away. Tillage also infuses oxygen into the soil, sending microbes into a feeding frenzy, because many of the microbes in the soil are aerobic and require oxygen for metabolism. Much of the carbon consumed by microbes is released as carbon dioxide, which is not captured and held in the system because tillage has eliminated any growing growing plants above. This leads to a net loss of carbon/organic matter from the soil over time. Loss of organic matter over time in conventional tillage systems is an issue because it negatively affects many facets of soil health and land productivity, including plant available water capacity, plant available nutrients and crop yield.¹⁰

Invasives even change the soil microbiome which negatively affects native plants! (https://www.sciencedirect.com/science/article/abs/pii/S0929139318311922)

Summary

In other words, succession only moves forward with the implementation of practices that promote soil health and support healthy populations of microbes, plants and animals.

Thinking back to the beginning with Surtsey Island and the thin layer of soil on top of rock and plants growing seemingly out of rock, this is the way things have to be or else soil and plants and microbes and diversity and rainforests and savannas wouldn’t exist. They’d be too susceptible to domination somewhere along the process and not make it. But we see natural ecosystems move toward abundance and diversity when left to their own devices. Health is the default setting. Apparently so is diversity and richness that move succession along.

Agriculture, as you might know, involves living organisms, so the same goals and strategies out in the wild also exist in the pasture, field or garden.

This is us. We go from dense mantle to less dense rock to less dense soil to less dense life. We go from barren to early colonizers to perennials. We increase species richness and diversity along the way.

Left to its own devices, nature creates diversity and color. We tend to create monocultures and monochromatic creatures (urban pigeons, rats, grey 1800’s butterfly example) We need to think about what it means to be healthy. In general, succession promotes an increase in diversity and richness of species, particularly in the transition from pioneer landscape to perennial species. The more modes of action, the more resilient. If only we had a product with hundreds of modes of action able to change with the changing nature of microbes, insects and weeds. We do! It’s called a rich, diverse biological community and it’s the most cost-effective product that a farm or ranch could ever invest in. Given the appropriate amount of energy and nutrients, it’s self-sustaining, self-regulating and self-healing. The reality is that we live on a planet where everything is constantly in motion and ever-changing. Organisms big and small have their different strategy of staying alive and reproducing by utilizing various available resources. Strategies differ, but the goal is the same. Think about invasive species like kudzu that are introduced into a new environment without a natural predator. In those special cases, ecological systems may need our intervention while the system readjusts to find a place for the invasive in its dynamic equilibrium. But that’s the thing, biology drives the system and a system with more diversity and abundance of life has a much higher chance of finding a healthy and balanced dynamic equilibrium. What happens if our antimicrobial drugs and pesticides lose their efficacy? We’re in for a world of hurt if we don’t change our management style to account for the resilience and speed of biology. Another way to think about it is that every farmer or rancher on the planet makes their living on a thin layer of icing on a thick, rocky cake. The only difference is the depth of soil to the parent material, generally speaking. Think about what lies beneath your feet, how your local soil formed, how it is sustained and how it can be improved with your management.

“Plant disease management has not significantly changed in the past 50 years, even as great strides have been made in the understanding of fungal
biology and the etiology of plant disease.” Species affect conditions and conditions affect conditions. Go out in nature and think about how those grasslands or forests aren’t overrun by disease or pests. If you live in an area with an invasive insect or plant, I feel for you.

Diversity of genes builds resilience. Think about pure-blood dog breeds and humans that mate with relatives.

There are many great people working in research and inside chemical companies trying to genuinely help the human race. And they are. It’s just that we can’t rely on these tools because nature always bats last. It’s too shifty and hard to keep up with. We need to play with her and not against her. Yes, those products are tools and they can and should be used in emergency situations. The same can be said for life-saving medication, like antibiotics. Rely on nature first and then when all else fails, use the products. Nature yields positive compounding and cascading effects. Many industrial products and mechanical disturbances have negative effects. With medicine, we call these side effects and we all know how long the list of those can be. That would be something if a list of side effects included, “gain of hair for balding men, may increase IQ score and mental clarity, muscle growth, more energy throughout the day, etc.”

Unfortunately, our human tendency to create arbitrary boundaries clouds our ability to see the similarities between biological systems. This tendency limits our ability to learn lessons from other industries, which is unfortunate because. Below are four of the most important of these principles.

The vast majority of organisms are beneficial and prevent opportunists from dominating. As the Cleveland Clinic writes, “Every person’s gut is home to trillions of microorganisms, most of which are beneficial. These helpful microbes perform many important services in your body, including preventing unhelpful germs from taking over.” (https://my.clevelandclinic.org/health/treatments/25202-fecal-transplant) Another service they provide is the excretion of health-promoting compounds after consuming undigested food in our intestines. One such byproduct is butyrate, a short-chain fatty acid which “forms the key energy source for human colonocytes (colon cells) and also has potential anti-cancer activity via the ability to induce apoptosis (programmed cell death) of colon cancer cells.” (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5847071/) Vitamin K₂, known to help the body clot blood, build strong bones and prevent calcium deposits in your arteries (https://health.clevelandclinic.org/vitamin-k2), is another byproduct of microbial metabolism. (https://pubmed.ncbi.nlm.nih.gov/6127606/)
Diversity and balance increase the number of services offered. “The more variety of these healthy microorganisms you have, the more they can do for you.” (https://health.clevelandclinic.org/what-are-prebiotics) “For the microbiome to flourish, the right balance must exist, with the healthy species dominating the less healthy.” (https://www.health.harvard.edu/blog/diet-disease-and-the-microbiome-2021042122400)
Available food sources largely determine the composition of active species. (AKA feed them and they will come) “The health of the microbiome is influenced by diet, and that the composition of the microbiome influences the risk of health outcomes.” (https://pubmed.ncbi.nlm.nih.gov/33432175/) “We show that consumption of particular types of food produces predictable shifts in existing host bacterial genera. Furthermore, the identity of these bacteria affects host immune and metabolic parameters, with broad implications for human health.” (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5385025/) Fermented foods improve diversity (https://med.stanford.edu/news/all-news/2021/07/fermented-food-diet-increases-microbiome-diversity-lowers-inflammation) Fiber comes in many types, feeding diverse species. (https://www.medicalnewstoday.com/articles/326402#Not-all-fiber-is-created-equal)
Disrupting the diversity and balance increases the risk of disease or predation. “Unsurprisingly, therefore, perturbation to the composition and function of the gut microbiota has been associated with chronic diseases ranging from gastrointestinal inflammatory and metabolic conditions to neurological, cardiovascular, and respiratory illnesses.” (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6314516/)

Agriculture is all about trade-offs. Tillage and other disturbances offer benefits today, while harming tomorrow. Farmers and ranchers that are willing to sacrifice today (yield, weed presssure, social negatives, etc.) for tomorrow are taking advantage of succession and the services that a healthy ecosystem can offer that only get stronger as time goes on. More and more pesticides and fertilizers are needed as time goes on. If they were so effective, why do we need more?

“The war on superbugs can’t be won.” (https://www.sciencedaily.com/releases/2024/01/240109121056.htm)

Conventional agricultural practices are highly disruptive to the natural ecosystem, so it’s unsurprising that many fields and pastures around the world resemble conditions in the early stages of succession. Remember, this is the stage that provides a competitive advantage to many weeds, pests and pathogens.

I’d like to reiterate my stance from previous articles that waging wars against nouns is never a winning proposition, so I’m of the opinion that viewing the situation as a war is doomed to fail from the start. We need to work with nature. Go with the flow of river rather than spending so much energy paddling against it.

Resistance at its core is all about reacting to changing environmental conditions and exposures, so the quicker a population can make changes, the quicker a population can work around it. Smaller organisms have a double advantage in that they can.

the only one sure-fire, long-term strategy to permanently eliminate the need to use mechanical or chemical disturbances to “control” weeds, pests and pathogens is to . The strategy is to seriously think about the environment that our actions are actively creating. Do our actions create conditions that give the opportunistic, r-strategists a competitive advantage or is it one that is conducive the growth and sustainability of a rich diversity of life, not least of which are our beneficial fungi? The latter option can only be done by following

This is arguably the biggest challenge facing the sustainability of farming and ranching. We need a field or pasture to produce in the short-term but it needs to be at the proper rate. Too slowly and we don’t produce enough food. Too quickly and we rob the future for the present, meaning we exhaust the soil ecosystem of its energy and fertility in the long-term. It’s a delicate inertial balance. Thankfully, regenerative producers and initial university studies are showing that it’s possible to produce for today while improving ecosystem health and function for the future. Striking this balance requires the understanding that the fields and pastures under our care are designed to flow in the direction of succession and are influenced by inertia. They are no different than the woods, savanna or grasslands that surround them. After all, they came from those climax communities in the first place! Therefore, it’s necessary for farmers and ranchers to understand that every creature in the ecosystem is on the same team working to keep the system moving and complex, especially “pests”, “weeds” and “pathogens”. *Gasp!*

Conditions in nature that pioneer species thrive in are bare rock and recently disturbed systems, by fire, tornado or other natural events. Agricultural disturbances like tillage and pesticide applications create conditions like bare rock and disturbed environments.

Nature is self-organizing, self-healing and self-regulating, which means that its natural tendency is to move toward complexity, resourcefulness and resiliency. Pairing this with pragmatism is the best way forward. It’s very challenging for a crop farmer to work within this framework but examples abound. Pasture management is easier in some respects but still provides great challenges.

There are many reasons to study ecology as an agriculture professional, not least of which are the profound life lessons that nature teaches us. First, we learn that context is key. Individuals find themselves embedded in their environment in a two-way relationship. Individuals affect their environment and the environment affects the individual. Second, everything happens for a reason when you take in the full context of the situation. Third, we all rely on each other. Many living and non-living factors work together inside of each individual ecosystem process. Zoom out a little further and we see that each of the 4 ecosystem processes influence each other and rely on one another. Fourth, time waits for no one. Fifth, we’re all capable of changing. Diversity Cycle (a.k.a. Community Dynamics) is Energy, Water and Nutrient Cycles. Life is tilted toward moving in certain directions. Understanding the strategies of weeds and pathogens allows us to avoid creating the conditions conducive to their reproductive success.

It’s my opinion that God instructed us humans to steward the land and animals wisely with the dominion he gave us for the short time we are here on Earth. What does stewarding wisely look like? From my studying of scripture, I would say wise stewardship is promoting life lovingly within, on and above the land. There are many ways to interpret scripture, so I don’t want to get into a verse battle, but I believe Genesis 1:31 provides good insight into stewardship: “God saw all that he had made, and it was very good.” From what we call weeds to microbes that can cause disease, God sees them as good. It’s our job to help create a balanced environment that allows them to be part of an efficient cycling of life. Even insects and “pathogens” can be useful for us as they tell us which plants in our fields are weak. What a beautiful way to view farming and ranching!

References

¹https://whc.unesco.org/en/list/1267/ ²https://www.sciencedirect.com/science/article/abs/pii/S0038071721002960 ³https://www.nature.com/articles/s41598-021-85955-3 ⁴https://www.almanac.com/what-weeds-tell-you-about-your-soil ⁵https://www.cs.montana.edu/webworks/projects/stevesbook/contents/chapters/chapter002/section004/blue/page003.html ⁶https://www.goodreads.com/quotes/17976-if-you-know-the-enemy-and-know-yourself-you-need ⁷https://extension.umd.edu/resource/pigweed/