Microbes help you grow healthy plants by transferring minerals and carbon dioxide to the plant. They also do a number of other great things in the soil. Read on.
Nutrients Are In The Soil
Most of the minerals feeding your plant come from the soil. A plant uses a lot of calcium, magnesium, phosphorus, potassium and sodium. These are called macro minerals. It also uses small amounts of other elements such as copper, manganese, molybdenum, zinc, iron, silica, and dozens more. These are called trace minerals. You can recognize these from the periodic table of elements. If the food you eat doesn’t get macro or trace minerals from the soil, you won’t get them either. How does a plant get the minerals it needs?
Microbes Supply Plants With Minerals
A plant gets nutrients and minerals from microbes in the soil. There are a LOT of microbes in healthy soil, trillions in a single teaspoon. Soil microbes and fungi break down particles of earth (minerals) in the soil until they are a size and form the plant can use.
Soil microbes also love sugar, which plants make through photosynthesis. Plants supply sugar to microbes through their roots and, when they do, the microbe brings minerals to the plant. Plants want what microbes bring, microbes want what plants produce. (Insert pic of plant and microbes trading resources?)
Microbes Help Plants When They Breathe
Microbes also breathe like you and I, inhaling oxygen and exhaling carbon dioxide (CO2). That CO2 comes out of the soil during the night, but, since it is heavier than air, it stays down in the plant canopy. In the morning, openings on a plant’s leaves take in that CO2. The process of photosynthesis in the leaves breaks apart the CO2 and uses the carbon to make sugar and releases oxygen in the process. Now the plant can feed the soil microbes with some of that sugar and continue the cycle of feeding microbes and taking in nutrients. High levels of CO2 in the atmosphere are great for plants, great for photosynthesis, and great for life on earth.
Microbes Add Carbon to Soil
Microbes are also essential to storing carbon in soil. How does this work? Sugar made by the plant is made up of carbon, oxygen, and hydrogen. When a microbe eats sugar it is digested and some of the carbon leaves the microbe as waste. Other carbon is used in building the body of the microbe. When the microbe dies its body is eaten by other microbes and organisms.
Plants also use carbon they get from the air (CO2 from microbe exhalation) for building their own tissue. When plants die they enter the soil through tillage or animal disturbance and microbes break down this plant residue by eating it. If you leave your plant residue on the surface, the nutrients oxidize into the atmosphere and your microbes go hungry.
All this carbon is now in the soil and that is very good.
Other Benefits of Soil Microbes
There are many varieties of soil microbes. They do various tasks such as fixing nitrogen, making phosphorus and other minerals available to plants, suppressing pests and pathogens, and helping plants when they are stressed. There are even microbes that break down herbicides.
Are There Microbes In My Soil?
You can see if microbes are flourishing in your soil simply by looking at your plants’ roots. Gently dig up a small garden plant, tap off the loose soil and look at the roots. If the roots are covered in what looks like a ‘fur’ of soil your roots are well populated with microbes. This layer of soil on the roots is called the rhizosphere.
What Hinders Microbial Life In The Soil?
– hard tight soil (i.e. soil that cracks when it’s dry)
– any and all pesticides
– synthetic fertilizer
– no-till or zero till practices (microbes suffocate and starve)
– water saturated soil (again, they suffocate and starve)
– shallow aerobic zone
– not enough carbon in soil
– low levels of plant residue
– soil with no plants growing (they starve without sugar from plants)
What Helps Microbial Life In The Soil?
– increase your aerobic zone ***link to blog post***
– minimize or eliminate all pesticide use
– lightly till plant residue into soil
– mineralize your soil with good soft rock phosphate
– apply biochar
– grow cover crops
– apply compost and/or compost tea
– add organic matter
Conclusion
Plants and soil microbes have a synergistic relationship because they each provide what the other needs in order to grow and thrive. The trading of sugar for nutrients is a win-win relationship. With all the other tasks microbes carry out they are an indispensable part of soil and plant health.
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