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Effective Microorganisms: Using Bacteria and Yeast to Create Sustainable Agriculture
Friday, 21 March 2014 00:00  |  Written by Aaron Lada, Ph.D. | Article

Lactobacillus Under a Microscope photo by Janice Carr, CDCPAn intimate understanding of the local ecology is necessary for successful agriculture—and it may be important to extend this knowledge to the smallest of lifeforms. According to Dr. Teruo Higa, a proponent of natural, sustainable, chemical-free farming, soil treated with beneficial microorganisms can produce healthier, more productive plants. To this end, he has created a proprietary mixture of beneficial bacteria and yeast called Effective Microorganisms (EM). Although the scientific jury is still out on its effectiveness, its potential is great for vastly increasing food yields while reducing chemical pollutants in the environment.

In typical soil, there are many different types of microorganisms using many different methods of obtaining and metabolizing food. Most of these microbes are responsible for breaking down organic material in a way that naturally recycles essential components back into the soil. Normally, among the dominate organisms present is putrefactive bacteria that decompose dead matter—producing foul-smelling waste products. According to Dr. Higa, when putrefactive bacteria are the primary microorganism in the soil, there is an increase of disease in plants and a proliferation of insect pests. His strategy is to replace putrefactive bacteria with a special cocktail of EM that will perform the decomposition duties, produce nutrients for the plants and prevent the invasion of harmful pathogens.

Components of EM
Dr. Higa’s EM product is a synergistic mixture of several naturally occurring, non-engineered microorganisms. Each member provides a benefit to the other EM and/or plants. The three major components are:

  • Lactic acid bacteria - They metabolize sugars using a form of fermentation that produces lactic acid as a waste product. Similar bacteria have been used for centuries to make products such as yogurt and cheese. These bacteria break down organic material in the soil, and the lactic acid produced is said to lower the soil’s pH (i.e., increases its acidity), which inhibits the growth of certain harmful bacteria.
  • Photosynthetic bacteria - Like plants, they use photosynthesis to convert the sun’s energy into sugars. These extremely efficient bacteria produce more sugars than they need, and the excess can be used by other EM and plants. In addition, they can convert nitrogen gas in the air into a form that plants can use (nitrogen fixation), and detoxify some of the harmful waste products from putrefactive bacteria.
  • Yeast – Like lactic acid bacteria, they use fermentation—feeding off of the extra sugars made by the photosynthetic bacteria—to produce a variety of vitamins, enzymes and antimicrobial substances that help the other EM and plants.

Benefits of EM
Dr. Higa claims that his EM will improve soil quality, enhance plant growth and increase crop yields. In addition, they will reduce the need for chemical fertilizers and pesticides, thus making environmentally friendly, sustainable agriculture possible. According to Dr. Higa, if his EM products were used globally, they could increase food yields enough to feed an additional 10 billion people, and even make agriculture possible in deserts. EM are not intended to replace other sustainable farming practices; instead, they are meant to be one component in a system that includes crop rotation, mulching, organic soil amendments and natural pest-control practices.

EM are claimed to be safe for plants, humans and animals, and are certified for use in organic farming. In fact, a few of the products are designed to be taken internally for health benefits. While some may balk at the prospect of using bacteria and yeast in this fashion, none of the organisms are pathogenic, and humans have long had beneficial relationships with a variety of microorganisms both internally and externally.

EM Products
EM Research Organization, Inc. (EMRO) produces several EM products based on Dr. Higa’s design:

  • EM-1® is a liquid soil inoculant used in agriculture. It can also be added to organic material to facilitate the production of compost, and used to reduce odors from sewage and livestock.
  • EM-1® Bokashi is added to food waste (including meat and dairy) to speed composting while producing few odors.
  • Dr. Don's® antioxidant oral-hygiene products, such as toothpaste and mouthwash, use EM Technology® to engineer fresher breath and cleaner teeth.

EM Controversy
Several studies—including those from Brazil, China, Costa Rica and New Zealand—claim to demonstrate a positive effect for EM. Yet, critics have cited flawed experimental design and statistical analysis that prevent definitive conclusions from being drawn. In particular, the effectiveness of single microorganism strains has been called into question. And studies from the Netherlands and Switzerland both concluded that EM had no effect.

Bokashi Composting photo by Al PasternakA publication from the Food and Agriculture Organization of the United Nations (FAO) states that there are promising claims regarding EM, however it goes on to warn that “many scientists have expressed their reservations about the product due to bio-safety concerns and lack of scientific evidence.” Critics of EM claim that it is difficult to change the microbial population of the soil with these products because there are simply not enough organisms to outcompete the normal inhabitants. Some of the success with EM may be due to low populations of native soil microbes in the study location, suggesting that EM could be effective if enough could be added. More independent research is needed to provide a conclusive answer.

Developing environmentally friendly agricultural practices for an ever-increasing human population will require innovative approaches such as Dr. Higa’s use of EM. While definitive evidence is lacking, EM products are an elegant combination of synergistic organisms that benefit not only each other, but the plants as well. Despite any uncertainty regarding EM, few can argue with Dr. Higa’s philosophy of using natural products to create an abundant food supply without harming the ecology.

Additional resources:
Background on EM

Natural Garden Pest Control
How to Compost and Build a Compost Heap
Breaking Down the Bones: How to Compost Meat and Other Animal Products
Become an Urban Farmer: Here's How
Permaculture: A System for Sustainable Living
How to Plant a Vegetable Garden

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Comments (4)add
Written by Dawid , May 26, 2014
This tomato farm produces 40% of South Africa's total tomato output, and they use EM for their composting and compost tea.

They almost lost everything due to ever decreasing crop yields and sickness of their plants which was caused by their dependence on chemical fertilisers and insecticides.

If allowable, here's a link to the Farm's website re: EM usage:
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Written by Adam , June 13, 2012
Dont buy it unless you are in a time crunch. It's fairly easy to make it yourself if you have about two months. All you need is rice, milk and molasses with a couple containers (one that seals tightly).
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Written by Aaron Lada , August 31, 2010
It is a neat concept, hopefully EM will be able to live up to the claims. Good luck, and please send an update with your results.
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Written by TMT , August 30, 2010
What a fascinating concept. I hope there are more studies to determine the efficacy of the product. In the mean time, I'm willing to take a chance. I plan to order some EM for my garden and see what happens.
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