EFFECTIVE MICRO-ORGANISMS or EM, a technology developed in the 1980s by the Japanese Professor Dr Teruo Higa. Naturally occurring micro-organisms such as yeasts, lactic acid bacteria, photosynthetic bacteria and fungi are cultured in combination. As EM they are used in various ways: to improve cropland soils, plant health and yields; to displace, through competitive exclusion pathogenic (disease-causing) microbes; in compost-making; to make fertilizer applications more efficient; in the treatment of waste water.