Effective MicroorganismsÂ® and EM Â® are the trademarks of Em Research Organization, Inc. (EMRO), Uruma City, Okinawa, Japan. EMRO has commercial licensees and manufacturers worldwide.
An effective microorganism refers to any of the predominantly anaerobic organisms, "very common species found in all environments as extensively used in the food industry", blended in commercial agricultural amendments or for environmental applications such as for septic tanks. EM products are purported to support sustainable practices in farming, improve composting operations, and to reduce environmental pollution.
Many of the so-called "pit additives" used for improving the performance of sanitation systems, namely pit latrines, septic tanks and wastewater treatment plants, are also based on Effective Microorganisms.
The Wiki article doesn't talk about EM 1, 2, 3, 4 specifically but does note that there are different blends of different kinds of bacteria
; Natural occurrence & food industries
*lactic acid bacteria; plant surfaces, soil, sauerkraut, silage, kefir, dairy; lactobacillus casei
*phototrophic bacteria; ubiquitous (air, water, soil, organisms); rhodopseudomonas palustris
*other bacteria; ubiquitous microorganisms that exist naturally in the environment; actinomycetales
*yeasts; skins of fruits/berries/crops, soil, insects; saccharomyces cerevisiae
*nutrient solution; pH 3.5 to 3.8; molasses]
This article talks more specifically about the different blends:
https://permaculturenews.org/forums/inde ... -em.12409/
EM is a blend of beneficial microorganisms developed by Teruo Higa, a professor at the University of the Ryukyu in Japan. These microorganisms improve the health of the soil, the plants, water and humans by breaking down organic matter in the soil, fixing nitrogen from the air, and feeding and protecting plants and animals. The organisms included are primarily yeast and pro-biotic photosynthetic bacteria and lactic acid bacteria. Buying EM is quite expensive, and you actually can make yourself at very minimal cost.
In Asia, they even further process the EM into 4 types of EM (EM1, EM2, EM3 and EM4) and become much more effective and best depending what you will use the EM for. Here is simple way to make your own EM.
EM1 is the original trademark product and contains a group of bacteria primarily lactic acid bacteria (lactic acid produced in metabolism), yeast, and photosynthetic bacteria. EM1 contains only three types of microorganisms in ideal proportions.
EM2 is a mixture of more microorganisms, which is about 10 types and 80 species. Microorganisms, like many in EM1, also exist together as a consortium. The main microbes that exist in the EM2 is a photosynthetic bacteria, fungi, yeasts or molds, and so on. Made in liquid culture medium with pH 7 and stored at pH 8.5. The population of microorganisms in the solution is about 10 (9) or 1 billion cells per gram of fluid.
EM3 consists of approximately 90% of bacteria photosynthesis and the rest are of other microorganisms. EM3 was cultured and stored at pH 8.5. Microorganism population in the fluid is also about 10 (9) or 1 billion cells per gram of fluid.
EM4 consisted of 90% Lactobacillus spp. and microorganisms that produce lactic acid more. EM is made by culture in liquid medium was acidic pH of 4.5. The number of microorganisms retained the same as above, ie 1 billion per gram of fluid.
Thatâ€™s the main difference between EM1, EM2, EM3, and EM4. So in principle, the differences caused by the content of microorganisms of each type of EM is. The one that mostly used in Asia to boost farming and fisheries is the EM4.
It is from a permaculture forum and the article is about how to make your own EM blends.