The invention of EM was originally invented in the 1970s by Teruo Higa, a professor of biology at the University of the Ryukyus in Japan. EM is the English abbreviation of Effective Microorganisms. It is a new type of compound microbial preparation. It is composed of phototrophic bacteria, lactic acid bacteria, yeast, actinobacteria and other 10 genera and more than 80 microorganisms. Having powerful advantages and incomparable power, these bacteria form a stable microbial system and cooperate with each other. Its mechanism of action is mainly manifested in the following aspects.

•	Agriculture: EM can promote the decomposition of soil organic matters and photosynthesis and also improve the physical shape of the soil to make it soft, breathable and permeable, while it can inhibit the reproduction of harmful microorganisms, reduce or eliminate the use of chemical fertilizers and pesticides in order to produce real green food.>
•	Animal husbandry: EM can improve feed conversion rate, promote animal growth and development, improve meat and egg quality, inhibit as well as eliminate the odor of feeding houses, improve the internal and external environment of animals, kill pathogenic microorganisms, inhibit the growth of spoilage bacteria and improve animal disease resistance and fertility, while it can greatly reduce the cost of feeding and help produce high-quality healthy green food.
•	Environmental protection: EM can be applied to environmentally friendly sewage and garbage treatment. It can promote the decomposition of organic pollutants and reduce biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Yet, it is low cost. In addition, EM is also widely used in other areas of life, such as medical care, beauty, deodorization, feed, preservation, ceramics and so on. EM is a safe and effective microbial complex. It is a technology that is friendly to human and the earth. It has been applied in various fields such as agriculture, animal husbandry, fishery, environmental purification, food processing, civil engineering, construction and health.