“If you get the soil biology right, there’s absolutely no reason to rotate to a different crop. Our understanding of agriculture is flawed. As human beings, when we start paying attention to how nature manages things, we start changing our agriculture to work the way nature works. Nature has been managing to do this process for the last three and a half to four billion years. I think she’s had a little bit of time to figure it all out.“
Why do we human beings have to be so arrogant—thinking we know better than nature? Pay attention to what nature does. The most important tool that you need is a microscope. This tool allows you to see what nature is actually doing, and then mimic her.”
– Dr. Elaine Ingham
Dr. Elaine Ingham is an American microbiologist, soil biology researcher, and founder of Soil Food Web Inc. She’s a world-renowned leader in soil microbiology and research of the soil food web. She is also the author of the USDA’s Soil Biology Primer.
Diego Footer hosted Dr. Elaine as a guest on his podcast show, In Search of Soil, where she explained why her findings suggest that crop rotation is no longer necessary. According to her research, crop rotation can be avoided by:
- Learning to use a microscope
- Balancing the bacteria-to-fungi ratio
- Planting perennial ground cover
Learning To Use A Microscope
Dr. Elaine believes the microscope is the most underutilized tool for farmers. While it can be intimidating at first, it has the power to give every farmer the ability to see exactly what is going on within their soil, removing so much of the guesswork when it comes to balancing the biology of the soil.
As the saying goes, “if you can’t measure, you can’t manage.” The microscope is the greatest asset in a farmer or gardener’s toolkit. It allows them to measure what is actually happening within the living community of their soil. Rather than just observing how the plants look as the gauge for the soil quality, a microscope allows you to measure exactly what is going on in the soil itself and manage it accordingly.
Dr. Elaine started a school called the Soil Food Web School, which teaches aspiring growers and soil consultants how to identify the organisms in their soil under the microscope, and then what to feed the soil in order to proliferate the kinds of organisms they’d like to see multiplied.
She says that the microscope is a very simple tool to learn, much less intimidating than most would assume. In their program, students are assigned to a mentor as they begin learning the microscope. There is a camera connected to their microscope, projecting it onto the computer screen, which is then shared with the mentor. The mentor walks them through a step-by-step process until it becomes second nature.
In addition to learning how to use the microscope and identify soil organisms, the program teaches students the overall theory of the soil food web approach, and how to make perfect compost, compost teas and extracts, and many other amazing skills.
By the end of the program, students are equipped to start a lab of their own so they can advertise consulting services to their local community, testing soil samples to help farmers fix the imbalances in their soil.
Balancing the Bacteria to Fungi Ratio
Once a person is empowered to use a microscope and identify what is happening in their soil, they are given the keys to restoring balance to the biology within that soil. When speaking of balance, Dr. Elaine is referring primarily to the balance of bacteria and fungi. She has found that ensuring a living soil is biologically balanced with the correct ratio of bacteria and fungi is the key to meeting the specific needs of a crop in a given location.
She claims that the only thing most people focus on in their soil is the presence of bacteria. However, soil with an overabundance of bacteria, but a deficiency in fungi and other nutrients, will not be able to produce healthy crops. She says even if crops grown in this kind of soil look acceptable, they will be void of the nutrients needed for a healthy diet when consumed by humans or animals.
Benefits of Balanced Soil
Dr. Elaine teaches that as people learn to bring a healthy balance of fungi to the bacteria in their soil, they will notice weed pressure being drastically reduced. She says fungi produce a form of nitrogen that feeds your crops, but not the weeds. In addition, germination rates go up with the proper balance of fungi in the soil.
Even when fungi are introduced to balance out the bacteria, Dr. Elaine teaches that tillage is the worst thing you can do to your soil when it comes to making nutrients available to your plants. By “slicing and dicing” the topsoil, you wipe out the beneficial nematodes which consume the bacteria and fungi, converting it into a usable form for the plants to absorb. She calls these nematodes the “predators” of the bacteria and fungi—which are crucial in the nutrient cycling process.
In addition to reduced weed pressure and faster germination, Dr. Elaine says the growers using her systems for restoring balance to the soil are also observing faster growth in their plants (earlier flowering and earlier setting of seed), more vibrant color, and substantially higher yields.
Different Balances for Different Crops
Dr. Elaine’s research has also identified how different crops prefer different bacteria-to-fungi ratios for their optimal health. So a balanced soil for one crop may not be balanced for another.
For example, the brassica family (kale, broccoli, cabbage, mustard, etc.) thrives in soil that has a higher ratio of fungi and fewer bacteria. In the Solanaceae, or “Nightshades” family (tomatoes, potatoes, eggplant, peppers), crops will thrive in a soil that has closer to a 50/50 ratio of bacteria to fungi. For perennial shrubs like grapevines and blueberries, soils will need to be more fungal-dominated. The time of year will also play a big role in the ratios of fungi to bacteria observed in the soil.
The Soil Food Web team is also happy to answer emails with questions concerning what kind of soil balance is required by different crops. Students of the Soil Food Web School will learn what kind of soil bacteria/fungi balance each crop prefers, along with the different techniques required to accomplish these balances in natural ways.
Planting Perennial Ground Cover
When it comes to the practical techniques for creating balance in the soil, Dr. Elaine’s method of choice is planting a strategic variety of low-growing perennial ground cover species, specifically matched to feed the annual crops that are planted into it.
In this system, an ideal bacteria-to-fungi population is fostered in the rhizosphere of the soil but the perennial ground cover, giving the specific annual crop all the nutrients that it needs for optimal health. The ground cover plants are low-growing, so as not to interfere with the upward growth of the cash crop. They also have a deep root system, bringing up nutrients and minerals that the shallow annuals would not ordinarily have access to. It’s a perfect symbiotic relationship.
The Soil Food Web also has all of this data for recommended combinations of perennial ground covers designed to be planted with all of the different vegetable varieties.
Dr. Elaine contrasts the ease and sustainability of this approach to all of the labor involved with so many of the farming practices we believe are mandatory for healthy crop production. She says with the right combination of perennial ground cover, “there is no need to do anything year after year for the next 2000 years.”
- There is no need to practice cover cropping, putting entire sections of your farm out of production for long periods of time and sacrificing the space that could otherwise be producing cash crops.
- There is no need to mulch, as the soil is already covered.
- There is no need to add compost, as the ground cover species create the fertility.
- There is no need to protect the soil from drying out and losing moisture.
- There is no need to protect from the compaction of the pelting rain.
- Finally, there is no need for crop rotation—our topic at hand!
Eliminating Crop Rotation
With a specific guild of five or six low-growing perennials designed to meet the needs of a certain vegetable crop family, it stands to reason that the annual rotation of crops to different plots would not fit in this system.
Dr. Elaine says when bacterial and fungal populations are balanced beneath a network of perennial ground covers, crops can be grown in the same plot year after year after year, only getting better and better with the passing of time. She teaches that the diversity that is created in the undisturbed biology of the soil beneath the ground cover plants will naturally prevent pest and disease problems from ever occurring. The nutrient cycling that will be taking place will ensure the plants have all the nutrients they need, indefinitely.
Dr. Elaine references blueberry meadows in the mountains of Oregon that date back a thousand years, started by the indigenous people of the land. How is it that these plants are not unhealthy and sick? How is it that these blueberries are some of the best blueberries you’ll ever taste?
While this all sounds too good to be true, the question is, could this actually work in a high-production market garden context? It’s quite a massive paradigm shift. How would a farmer plant close-spaced crops like carrots, or baby greens? How would tools like the Jang Seeder and the Paperpot Transplanter work in this context? The low-growing perennial ground cover could work well for wider-spaced, hand-transplanted crops planted 12” or more apart, but what about all of the other crops?
For these other crops, the Soil Food Web recommendation would be creating high-quality balanced compost from local materials with native microorganisms. While there wouldn’t be all of the same benefits of the low-growing perennial ground cover system, it will allow market farmers to still apply the same science in their approach to balanced soil biology, just with a little more labor involved. The amount of compost needed is also greatly reduced when the biology is correctly balanced.
Soil Food Web Consultant Renald Flores reported an average increase in yields of 72% across 8 different types of crops in his market garden near Stockholm, Sweden. You can view his video on that process here.
Knowledge is power. If there is new knowledge to empower small farms to produce higher yields of healthier crops with less labor, then it is always worth exploring. However, with new discoveries that usher in major paradigm shifts, small increments of change over time can often yield the most lasting results. For a more in-depth look at this new approach to agriculture from Dr. Elaine Ingham, make sure to listen to the full episode of In Search of Soil with Diego Footer.
Want to learn more?
Follow us on Instagram @moderngrower
Listen to our podcast Farm Small, Farm Smart
Thanks for another great article. I particularly appreciate how you highlight the technical challenges of how to manage crops in a living mulch system. Are you aware of any farms successfully using such a system for annual vegetables?
Also, what specifically are these ‘low growing ground covers’ ? White clover and some fescues?
This year we’re doing a number of trials (1/2 acre in total) with various combinations of cover cropping, woodchip mulching, and tarping to experiment with no-till veggies…. I’m thinking that it would be best to terminate the previous ground cover using tarping and then reestablish a new ground cover once the veg crop has had the time to establish. We’ll be focusing on transplanted crops to start with… direct seeded crops will be a whole other ball game.