6 Principles of Soil Health: Animal Integration

Teamwork Makes the Dream Work

Plants, animals, and soil have developed alongside each other for a long time. A long, long time. Historically, large packs of herbivores glided across landscapes to the rhythm of the seasons and the prodding of predators, only to return to the same spot months later. Plants and soil greatly benefited from this rest and recovery period. Animals like pigs and chickens found their niche in the diverse environments of the forest, where they had a plethora of feeding options to choose from. Browsers and grazers in the forest are necessary to ensure that the understory is not overgrown and fuel for a massive, intensely hot fire does not pile up. Tree-dwelling creatures also interacted with plants from above, while soil-dwelling creatures kept balance down below.  It’s a beautiful song-and-dance.


While it may be easy to think plants are helpless bystanders in the story, this is simply not true. Plants are able to respond to stimuli, trade resources with neighbors and conjure up complicated chemical compounds to protect themselves and their neighbors from danger. Plants even determine when animals will graze on them by decreasing production of compounds that make animals sick and increasing compounds that they enjoy. Coerced by deliciousness, animals grazed, excreted, and trampled organic matter onto the ground at the appropriate time which increased the odds of seed germination. Dr. Fred Provena’s Nourishment is a must-read to learn more about plant and animal nutrition wisdom.


All the while, animal and plant interactions improved soil biological, chemical and physical properties. Short, intense grazing events in grasslands followed by long rest periods are conducive to strong plant regrowth, which ensures that roots will feed soil biology. Well-fed soil biology is well-functioning soil biology. Grazing and predation in forest ecosystems keeps understory plant communities in check, which allows for healthy trees and a strong canopy that regulates airflow, temperature and moisture. This is great news for microbes as many prefer adequate levels of oxygen with consistent, mid-range temperatures under moist conditions. Not to mention, fungi thrive in the slightly acidic conditions that are found in healthy forests, and we know how important fungal communities are to soil health!


When done correctly, animal, plant and soil interaction on a farm or ranch will mimic the balance and resilience achieved in natural grasslands and forests. This leads to healthier ecosystems and more dollars in our pockets.

Decoupling of Land and Animal

Prior to the Industrial Revolution, animals lived in the same place as crops were produced. Donkeys, mules, oxen, horses and others provided most of the horsepower (how come horses get all the credit?) required to plow, plant and transport a crop. Modern technology developed in the past 150 years eliminated the need for families to keep animal employees on the farm. Additionally, animals were kept on farm for the meat, milk and fiber they produced. This began to change in the 19th and 20th centuries when agriculture slowly morphed into the hyper-specialized, globally-focused system we see today. The current system was largely shaped by “shifts in the political economy of global food systems, including an orientation toward capitalist logic, including surplus production, liberalization of trade, technological supremacy, and financialization.”1,2


The fact is that modern agricultural systems moved livestock off the land into confined animal feeding operations (CAFO), where they are to be fed by cheap monocultured crops. USDA and EPA figures from 2019 show that 99% of US farmed animals are living in factory farms.3 I don’t cite this statistic to argue for or against these changes. In fact, I’m of the opinion that honest assessment and improvement of our current agricultural system can only be done by acknowledging both the strengths and weaknesses of every production system. What I will do is show that the reintroduction of livestock onto the land is a worthy endeavor both ecologically and financially.

Cropland used only for pasture or grazing the a, United States and b, Corn Belt (IA, IL, IN, OH) from 1925 to 2017 (USDA-NASS 1945, 1969, 1982, 1987, 1992, 1997, 2002, 2007, 2012, 2019a). Smart et al. (2020)

Animal Impact on Soil Health

Let’s talk poo. Approximately 70-80% of the nitrogen (N), 60-85% of the phosphorus (P), and 80-90% of the potassium (K) in feeds are excreted in the manure and urine of livestock.4 This amounts to roughly .2-.3 lb N, .15 lb P and .5 lb K that is applied to the land each day by one cow. The majority of plant available N is present in urine in the form of urea (CONH2)2), which rapidly transforms into ammonium (NH4+) and then ammonia (NH3) gas as it dries. The key is to apply manure and urine to growing plants with active roots that take up the N before it is transformed into a gas and lost for plant growth purposes. Manure is also an excellent source of P and K. Be aware, though, that P and K overapplication of manure can lead to toxic levels of P and K much quicker than N. If you haven’t already, check out the 2nd principle of soil health to learn more about manure safety.


Why not just apply conventional N,P,K fertilizers? The reason is that manure brings much more to the table than plant-available nutrients. Livestock manure is chock full of organic matter like semi-degraded plant material that feeds and houses biology in the soil, giving them the energy, nutrients and shelter they need to provide services necessary for a healthy soil ecosystem.5  Over time, the increase in soil organic matter from manure6 improves cation exchange capacity (CEC), accelerates the extraction of nutrients from soil minerals for plant use, buffers pH, speeds up water infiltration and improves water-holding capacity.7  Many expenditures on farms and ranches are purchased to achieve similar results, so it’s no surprise research found organic matter levels in the soil directly correlated to proximate farm profitability on various corn farms, while yields did not correlate to profitability.8


Speaking of profitability,  one of the best ways to receive a great return on investment for cover crops is to graze them directly where they’re planted. This can be done by using one’s own livestock or by “custom grazing”, which allows someone else to bring their livestock onto the grazing site. In the first case, cover crops pay directly by turning plant growth into marketable pounds of animal. In the latter case, money is earned for allowing someone else’s livestock to do it instead. It’s important to communicate with the custom grazer before they begin that they must graze their livestock in the manner that best benefits you and your land. I advocate utilizing adaptive multi-paddock (AMP) grazing because of its researched benefits of increasing C, N, calcium (Ca), magnesium (Mg) and potassium (K) levels in the topsoil.9,10 In addition, the combination of hoof action, root growth and organic matter increase can relieve compaction issues.11


While cows, sheep and goats are likely the most popular grazing animals in your neck of the woods, introducing pigs and chickens back onto the land is also worth looking into. Pastured pigs can be used effectively to aerate compacted soil and increase seed-to-soil contact through hoof action, but careful attention must be paid as pigs can tear up a field rather quickly.12 As for reintroducing chickens, Richard J Bednarek, Jr, state soil scientist in Iowa for the USDA-NRCS, says, “In my opinion, having chickens on pasture is good for soil health. The chickens will on feed insects including the non-beneficial insects in the Soil Food Web. The chickens will eat the weed seeds reducing-to-eliminating weed pressure and improving the pasture vegetation’s root system. The roots hold the soil in place, improve soil structure, increasing water infiltration and improving soil biology with increased root exudates feeding the microbes. The chicken litter is high in phosphorus, helping low-phosphorus pastures.” Chickens are also one of the best, if not the best, tramplers of plant material onto the soil surface, which provides food for soil biology and a good layer of armor.

Joel Salatain Mobile Pastured Chicken Units
Eggmobiles are common structures to get laying hens out on the land.

All in all, the divorce of animals and land, along with mechanical and chemical disturbances, leads to degradation of the soil resource. In fact, one study showed that estimated species richness levels of multi-celled microbes (fungi, protozoa, nematodes), soil fauna and vascular plants were consistently reduced as a result of grazing removal in a grassland setting.14 At the other end of the feeding spectrum, removal of apex predators is just as detrmental to ecosystem functioning. Just read about the disastrous ecological results due to the elimination of wolves in Yellowstone, as well as the miraculous recovery since reintroducing them. I find it beautiful that every creature big and small plays a role in maintaining their home environment.


That reminds me, we must not forget the enormous impact on soil health from our tiny insect friends. After all, insects (and arthropods as a whole) are animals too. They’re the largest and most diverse group of animals in the animal kingdom, for Pete’s sake!  Too often we, myself included, take for granted all of the services that they provide us. First, we have pollination. According to the U.S. Forest Service, 80% of all flowering plants and over three-quarters of the staple crop plants that feed humankind rely on animal pollinators.15 Bees receive the lion’s share of attention, but ants, birds, bats, beetles, butterflies, flies, moths and wasps also get in on the action. Without them, we wouldn’t chocolate, cherries, strawberries and a whole host of other delicacies. God bless these little creatures.

Second, is the translocation, breaking and decomposition of organic matter into the soil.16 This process is called “bioturbation” and it greatly increases nutrient cycling and soil structure formation, which ultimately improves water infiltration and water-holding capacity. Bioturbation becomes a critically important process with the reintroduction of livestock to the land. Dung beetles and other poo-loving creatures will consume and drag down manure into the soil where it can decompose and add moisture and fertility where we need it most. Be aware that antihelminthics and insecticides administered to livestock, like commonly used avermectins, can pass through the animal and accumulate in the manure, thus killing many beneficial insects in the soil ecosystem. In fact, research shows that AMP grazing and the elimination of prophylactic ivermectin are two ways to achieve greater insect species richness, diversity, predator species abundance, and dung beetle abundance.17 Careful consideration must be made if you do plan on making changes to medication regimes. Keep the long-term goal in mind, which is to offer livestock a diverse array of grasses, forbs and legumes to help them balance their diet and consume health-promoting phytonutrients (nutrients made by plants). Many of these phytonutrients are naturally antiparasitic, so make sure livestock are getting them in their diet before taking them off of the pharmaceuticals or else disaster could quickly show up.


Dung beetles, called "scarabs", were important to the Egyptian culture, as evidenced by their appearance on many heiroglyphs.
Different functional types of dung beetles.

I will finish by quickly mentioning that building richly diverse populations of insects is the best pest management strategy for crop production. Dr. Jonathan Lundgren, entomologist and founder of the Ecdysis Foundation, states that for every 1 insect we deem to be a “pest”, there are close to 1,700 insect species that are beneficial to us. Healthy plant growth improves soil health for myriad reasons, so pest management is most definitely a matter of soil health! One study showed that pests were “10-fold more abundant in insecticide-treated corn fields than on insecticide-free regenerative farms, indicating that farmers who proactively design pest-resilient food systems outperform farmers that react to pests chemically.”8 Research investigating insecticidal seed treatments on soybean found “no yield benefits of insecticidal seed treatments over the 2 years of the study at this location [in South Dakota, USA]. Natural enemy communities [of soybean pests] were significantly reduced by thiamethoxam seed treatments relative to the untreated control.” Soybean aphids, thrips, and grasshopper populations were unaffected by the insecticidal seed treatments in the field, while bean leaf beetle population were reduced.18


The moral of the story is that insects should be viewed as equally essential to soil health as our livestock. Investing in strategies to increase their populations is money very well spent.19


Every single terrestrial landscape on Earth developed into the highly functional, highly efficient system we see today with the assistance of animals. Farmers and ranchers worldwide are seeing drastic improvements in soil health by mimicking nature through the reintroduction of animals. Now, it must be said that livestock reintroduction is not a viable option in everyone’s context. The good news is that soil health can still improve greatly by implementing other regenerative practices, such as reducing tillage and planting cover crops. David Brandt’s 40+ years of improvement are an inspiration for operations without livestock.21 The not-so-good news is that this likely lowers the ceiling on soil health potential and slows the rate at which improvements could have been observed. It’s all context dependent!


One of the most fundamental truths to get lost in the hustle and bustle of life is that we humans are the single most influential animal species on Earth. We have the potential to either improve or degrade ecosystem functioning and soil health like no other creature.  Dr. Fred Provenza worded it masterfully when he wrote that, “We are members of natural communities: what we do to them, we do to ourselves. Only by nurturing them can we nurture ourselves.”20


All life is connected. We rely on each other to properly function like different parts of the same body. Soil, microbes, plants and animals.