Two of the most important environmental problems we face today are 1) the current state of the soil and 2) the health of this nation. These two issues are ultimately linked. One of our goals as future farmers will be to work to return health back to the soil & encourage others to do the same to ultimately improve the nutrient content of our food.
In this blog post we cover HOW and WHY we have a soil problem, what conventional ag does to the soil, and how regenerative ag can ultimately fix this problem by building new top soil.
So let's get started. We have both soil degradation (meaning the health of our soil has plummeted) and we have had significant top soil loss from soil erosion. In fact, each year, an estimated 24 billion tonnes of fertile soil are lost due to erosion (1). That’s 3.4 tonnes lost every year for every person on the planet. Further, there is an estimate that if the current rates of soil degradation continues, all of the world’s top soil could be gone within 60 years (2). Much of this soil degradation is a result of the destructive practices commonly used in conventional agriculture.
So... the bad news: our soil health is crap, and we have lost a lot of topsoil.
Good news: we can regrow top soil, and doing so would help reduce the atmospheric levels of carbon. Regenerative agriculture is an incredible agricultural tool we can leverage to improve the health of the soil and ultimately reduce atmospheric carbon levels.
Having high carbon levels in the atmosphere does not mean carbon itself is a bad thing. It is not, and it is needed for all of life!
Dr. Christine Jones, an Australian soil ecologist, describes the carbon cycle with 3 phases: gas, liquid, solid.
The main problem we all face environmentally is that too much of the carbon that used to be in a solid phase underground has now become a gas that is sitting in the atmosphere.
Improving soil health through regenerative agricultural practices will sequester some of that carbon in gas form into the environment and convert it to a solid phase in the soil.
What are some of the consequences of the soil problem?
- Environmental impacts, since many farm lands with unhealthy soil are now net carbon sources, not sinks
- Health impacts since there are less nutrients in our food (we will return to this point later)
- Reduction in water-holding capacity of the soil. With poor groundcover and water-holding capacity, rapid water run-off not only leads to flooding, but also takes a lot of topsoil with it. And with all of the synthetic inputs used in conventional agricultural practices, these days it’s not just soil, but a heap of chemicals too — which end up in the Gulf of Mexico.
HOW DID WE GET TO THIS POINT?
Current farming practices. US Agriculture has the theme of “Go Big or Go Home.”
It is dominated by large, specialized crop and animal farms which focus on short-term productivity, at the cost of the environment and our health.
The typical farm grows just 1 or 2 crops, or raises 1 or 2 types of animals, and does so on a large scale. While this monoculture style of farming makes food cheap & abundant, it breaks the cycle of nature. It negatively affects the environment, the economy of rural America and the health of our soil, and as a result, our nation.
HOW CAN WE BUILD SOIL
There is unfortunately widespread belief that soil formation is an exceedingly slow process.
But most of the ingredients of top soil come from the atmosphere – carbon, hydrogen, oxygen and nitrogen.
Soil building involves the 3 phases of carbon: gas, liquid and solid, and it involves transforming carbon from a gas to a liquid then to a solid.
We first must review how plants make energy.
Plants are autotrophs – they feed themselves by combining light energy from the sun with the gas form of carbon - CO2 in the environment - to produce biochemical energy. Sugars are formed in plant chloroplasts during photosynthesis.
As you can see, there is carbon in these sugars. So the liquid carbon phase is essentially these dissolved sugars.
Now we need to cover one of the most important partnerships in nature: plant roots & mycorrhizal fungi.
Mycorrhizal fungi colonize roots and are more effective in nutrient & water absorption than roots themselves since they are deeper in the soil. Under the right soil conditions, there is a mutually beneficial relationship between the plant and the mycorrhizal fungi. The relationship centers on the plant’s ability to produce sugars through photosynthesis, and share some of these sugars with the fungus, in return for otherwise unavailable water and nutrients sourced from the soil.
So it is a two way relationship of sharing resources. Fungi rely on the plant for food, and plant’s performance and survival are enhanced by the fungus
Between 85-90% of the nutrients plants require for healthy growth are acquired via this carbon exchange – plant roots provide energy to the microbes by exuding liquid carbon in exchange for minerals and trace elements otherwise unavailable to the plant. Plus, in dry times mycorrhizal fungi supply water.
These fungi can extend far from plant roots and form networks between plants and colonies of soil bacteria, enabling plant communication. Thus, mycorrhizal fungi are both the highway and Internet of the soil -- highway to transport nutrients in both directions, and internet to transfer information.
Plants colonized by mycorrhizal fungi can grow much more robustly despite sending the fungi nearly half of the sugars they make from photosynthesis.
Now we need to cover the term ‘aggregate’, which is the fundamental unit of soil function. Most are connected to plant roots or mycorrhizal networks. Liquid carbon comes into the aggregates and enables the production of glues and gums that hold the soil particles together.
Under appropriate conditions, a large proportion of the soluble carbon channeled into aggregates undergoes humification, a process in which simple sugars (liquid carbon) are resynthesized into complex carbon polymers (solid carbon phase) – called humus. Not hummus, humus. Humus polymers are made from carbon and nitrogen from the atmosphere and a range of minerals from the soil. These organo-mineral complexes form a stable and inseparable part of the soil matrix that can remain intact for hundreds of years. The formation of humus requires a vast array of soil microbes, including mycorrhizal fungi, nitrogen fixing bacteria and phosphorus solubilizing bacteria, all of which obtain their energy from plant sugars (liquid carbon).
Humus is hard to conceptualize, but humus can’t be extracted from the soil any more than wood can be extracted from a tree. Once atmospheric carbon dioxide (carbon in gas form) is sequestered as humus (carbon in solid form) it is highly resistant to decomposition.
In summary, plants sequester carbon in gas form for photosynthesis and create sugar, which is pushed down into the soil in a liquid carbon form to the fungi. Under the right soil conditions, soil microbes use sugars to create complex, stable forms of carbon (solid phase). This flow of liquid carbon to solid carbon is the primary pathway by which new topsoil is formed and has been occurring for millions of years.
Critiques of carbon sequestration potential
Many critiques downplay the potential for carbon sequestration in agricultural soils. According to Dr. Christine Jones, much of the agricultural research is flawed for a few reasons:
First, many people assume that soil carbon sequestration occurs as a result of the decomposition of organic matter such as crop residues. When carbon enters the soil ecosystem as plant material, it decomposes relatively easily and returns to the atmosphere as CO2. These articles fail to mention plant roots, liquid carbon or mycorrhizal fungi. In doing so, they overlook the major pathway for topsoil restoration: the carbon sequestration pathway.
Second, a lot of research is performed in places where soil building is not happening, where carbon is running down and soils are deteriorating. More studies should be performed on farms where soil-building is occurring, like on regenerative farms such as Gabe Brown’s ranch.
Third, a lot of research occurs in pots in glass houses where the soil has been homogenized. This blending breaks up the mycorrhizal fungi. Plus, a lot of the soil organisms have died since the soil is often stored for a long time prior to the experiments. So in these type of environments, yes plants will respond positively to applied fertilizers since they don’t have any other way to obtain nutrients.
Fourth, with many of the field trials, the soil has been cultivated (tilled) or bare fallowed (left barren for a bit), so mycorrhizal fungi will not be there in sufficient quantities for effective carbon flow and nutrient acquisition.
And finally, many think that minerals in the soil are scarce since they are not in a form available to plants. But, a soil test will only tell you what is available to plants by passive uptake. The other 97% of minerals will not show up on a standard test since they are made available to plants via microbes and the carbon pathway. By taking care of microbes in the soil, we increase the availability of a number of minerals and trace elements.
How conventional agriculture destroys this carbon pathway
Essentially, the way many people currently farm interrupts the natural carbon flow from gas to liquid to a solid.
Tillage - turning over the soil with a piece of equipment. So the organic matter that was buried in the soil for hundreds of thousands of years, that’s been built up, is now exposed to oxygen. Essentially, this process inverts what’s been buried 6-9 in down. Bringing it to the surface exposes the organic matter to rapid decomposition.
When soil is cultivated, soil releases carbon into the atmosphere and thus doesn’t retain as much carbon.
Plus, this process literally breaks up the mycorrhizal fungi networks, meaning the plants can’t obtain nutrients from the fungi. So of course they will need synthetic fertilizer to get any sort of nutrients.
2. Synthetic inputs
Synthetic fertilizer gives plants free nutrients – so they don’t really need the mycorrhizal fungi anymore. They no longer need to trade carbon for nutrients from the mycorrhizal fungi, and instead keep a lot of the carbon for themselves. As a result, the microbes don’t get enough food to grow and reproduce, so their populations suffer.
But, synthetic fertilizer only supply a limited amount of nutrients to the plants, not the full range plants need. The full range that is provided to the plants via the mycorrhizal fungi that reach much deeper into the soil. This is why our plants are now nutrient deficient, which affects our health.
The biocides (which are chemicals that kill living organisms) not only increase the toxin levels in our food, but also reduce the nutrient content of food, all of which destroy the plant-microbe bridge.
Moreover, there are environmental implications. Since plants no longer need to send carbon to the fungi, the photosynthetic capacity of plants is not maximized. Less carbon is being pulled out of the atmosphere and there is carbon sequestration.
Think of all those barren fields with unhealthy soil… so much carbon sequestration potential!
Monocropping is the agricultural practice of growing a single crop year after year on the same land. In the midwest, this is commonly corn and soybeans. This is NOT NATURAL in nature!
There is no diversity which means the soil biology is not being maximized.
Plus leaving the land barren for 2/3 of the year starves out the soil’s natural fertility. Like us, microbes need food all year round! This is why many farmers have to use copious amounts of fertilizer to grow a crop – there’s no microbes left in the soil!
So if we know of these issues, why are people still tilling and applying chemicals?
Conventional agriculture continuously teaches you must till and apply chemical inputs to drive crop growth. Big ag is one of the largest industries in the world, and make a ton of money on synthetic inputs. If farmers added diversity, used minimal tilling or no-till methods, and planted crops all year round, their fields would eventually re grow strong mycorrhizal fungi connections, and would no longer need the synthetic inputs. But why would Big Ag companies want people to STOP using their chemicals?
Plus, farmers are not incentivized to stop these destructive agricultural practices. We are stuck in an environment where farmers are rewarded on maximizing yield in a short period of time. Government subsidies pay no attention to food quality or how good their soil is, and instead the value of land is based on yield.
Making changes are a financial cost to the farmer, and many would not see the benefits immediately. So, short term how can the farmers get the loans & funds to make these changes? We need to build programs that provide support for the farmer to take those risks. A company called Pachaterrae, led by Dr. Nichols company, helps farmers and ranchers measure the amount of carbon they put back into their soil. These measurements help farmers get compensated financially by the Canadian government to help offset carbon while serving as land stewards. How cool is that!
So, part of the solution may be to reward innovation in land management. We must incentivize farmers by financially rewarding them to build carbon in their soils.
A few take away points...
1. Conventional agriculture fails to build stable soil carbon
Mycorrhizal fungi have been destroyed overtime by current agricultural practices. Tilling destroys the fungi, and synthetic fertilizer interrupts the root-mycorrhizal fungi relationship since plants get free nutrients. So, many agricultural production systems fail to build stable soil carbon (carbon in the solid phase) with non existent or deficient plant-microbe bridge. Many crop fields are net carbon sources. And we don’t have time for this nonsense anymore.
2. Our food has less nutrients due to the degraded soil.
With less plant root-mycorrhizal fungi relationships, plants are not getting the full spectrum of nutrients they need and are instead getting a limited amount of nutrients from synthetic inputs. It is a negative cycle – conventional agriculture breaks the root-fungi relationship, plants get less nutrients, and more synthetic input is needed.
On top of that, we are selecting for plants that produce a lot more seeds. So the already limited amount of nutrients a plant has are spread out to more seeds. As a result, the plant fills the seeds with more sugars to get it to a certain size.
Thus, our food has decreased mineral & nutrient contents.
3. Food with less nutrients leads to an unhealthy nation.
Since foods have less nutrients, we have to eat more calories to obtain the nutrients we need. The result is a nation that is malnourished and obese. Why aren’t we paying more attention to the fact that our life expectancy is declining? Despite having access to all of this incredible technology?
4. Soil without carbon flow is trash.
Soil without carbon flow will deteriorate – it is hard & compacted. Carbon is needed for soil structure, water holding capacity, and to feed the microbes involved in nutrient acquisition.
5. Regenerative agriculture can help us rebuild soil.
A practical and beneficial option for productively removing excess carbon dioxide from the atmosphere is building good top soil through regenerative agriculture practices.