noun
effective microorganisms; EM
Technical term in agriculture and environmental science referring to a mixed culture of beneficial microbes. Often abbreviated as EM.
有用微生物群を土壌に投入すると、作物の生育が改善されることがある。
Applying effective microorganisms to the soil can sometimes improve crop growth.
EM（有用微生物群）は、環境浄化にも利用されている。
EM (effective microorganisms) is also used for environmental cleanup.
Compound of 有用 (useful) + 微生物 (microorganism) + 群 (group). A modern technical coinage, likely calqued from English 'effective microorganisms'.