How the Microbes in Effective Microorganisms Improve Soil Fertility
- 16 July 2013
Agricultural production begins with photosynthesis - the conversion of solar energy into chemical form. It’s an amazing process, but not a particularly efficient one. Even rapid growing plants like corn and sugar cane only fix a maximum of six to seven percent of the sun’s energy. One way to increase the amount of energy fixed, is with photosynthetic bacteria and algae. These utilize wavelengths that green plants do not.
The mainstays of EM are the photosynthetic bacteria (Rhodopseudomonas spp), lactic acid bacteria, (Lactobacillus spp) and yeasts (Saccharomyces spp). Photosynthetic or phototropic bacteria are independent self-supporting microbes. They use the energy of sunlight and soil heat to convert secretions from plant roots, organic matter and harmful gases into plant useful substances like amino acids, nucleic acids, sugars and other metabolites. These can all be absorbed directly into plants to promote plant growth and also increase other beneficial microorganisms. For example VAM fungi increase in the root zone in the presence of amino acids secreted by these bacteria. In turn the VAM fungi improve the plant’s absorption of soil phosphates. The VAM can live alongside Azotobacter and Rhizobium and increase the capacity of plants to fix Nitrogen.
EM also includes lactic acid bacteria. These produce lactic acid from the sugars and carbohydrates the photosynthetic bacteria and yeasts produce. This is a strong sterilizing compound and can suppress some disease inducing microorganisms and nematode populations. It also contributes to the fermentation and breakdown of the tough cellulose and lignin. Here’s our soil digestive processes getting a help along. The yeasts in EM have other uses. They produce hormones and enzymes that promote plant cell and root division. They use the amino acids and sugars secreted by the photosynthetic bacteria and plant roots and in turn give off substances which are good growing compounds for the Lactic acid bacteria. So all three species have a separate role to play, and help each other. They also have a symbiotic or mutually beneficial relationship with the roots of plants. So plants grow exceptionally well in soils dominated by these Effective Microorganisms.
Bacteria and microbes live, reproduce and die, at enormous rates and in doing so release a constant stream of nutrients in plant available form. They collect nitrogen and other nutrients from the soil organic matter and mineral particles. They reproduce, so more microbes are collecting and converting nutrients. They die and release what they have collected in a form the plants can use. The plants grow better, assimilate more energy and provide more food for more microbes and so it goes on.
It’s a two way process. Living plants absorb energy from the sun, incorporate it with carbon dioxide from the atmosphere, water and nutrients they require from the soil. Then they release oxygen back to the atmosphere and carbon to the soil as carbohydrates, glucose and other carbon forms for the microbes to feed on. The size of this microbial population is governed by the inputs from the plants, the primary producers.
We can see the grass and trees growing on top of the ground. But scientists tell us that fifty percent of a plant’s primary production disappears underground to establish the root network and feed the microorganisms. That is what happens in a healthy natural system. It is a mutually beneficial relationship that has evolved over eons and led to the formation of our most fertile and well-structured soils. Even the timing is perfect. In most natural systems, the greatest microbial turnover and release of nutrients, coincides with the plant’s growth and its seasonal needs.
Understanding this helps us see the danger of farming systems and landuse activities that starve the soil of carbon matter. No carbon means no food for the microbes. No food for the microbes means no turnover of nutrients. No nutrients means no plant growth which means no carbon inputs and so it goes on into a downward spiral with loss of fertility, loss of structure, erosion and so on and on. So our effective microorganisms are only going to remain effective if we manage our pastures with them in mind too. That means not overstocking or baring paddocks. It means allowing pastures to develop enough leaf to do their photosynthesis number effectively and fix some carbon for all the other little greeblies further along the food chain.
EM has been subject to a variety of trials within New Zealand on everything from sheep and cattle farms to onion growing. Generally it has been shown to have a reviving action on growing systems. It can improve soil quality, soil health, and the growth, yield and quality of crops. It helps in the decomposition of organic matter and during fermentation produces several normally unavailable organic acids; lactic acid, acetic acid, amino acid, malic acid and various other bioactive substances and vitamins. It has an antioxidant effect, which improves the immune system of both plants and animals.
For more information on both NZ and international trials visit our research page.
For more information about how EM impacts the soil and fertility see the below related blog posts:
- What will EM do in my Soil
Increasing Organic Matter and Biology in Pastoral Systems – Targeted Biological Inputs
For more information please contact us.