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Chapter 18 EM: A Microbial Product for Sustainable Agriculture

Peter N. Chandi

Microorganisms are widely utilized in human medicine and health, food processing, agricultural biotechnology, environmental protection and the treatment of wastes. These organisms are most effective when introduced into a suitable environment containing substrates that match their metabolic needs. Professor Teruo Higa of Ryukus University in Japan identified several microorganisms that promote agricultural production and environmental conservation (Higa, 1993). The microorganisms are packaged as “EM Technology”, including a product “EM1”_® that is stocked in Kenya by several retailers.

This technology consists of naturally-occurring microorganisms that are compatible with one another and can coexist in liquid culture. The microorganisms include photosynthetic bacteria (Rhodopseudomonas spp.), lactic acid bacteria (Lactobacillus spp.) and yeast (Saccharomyces spp.). When in contact with organic matter, they secrete beneficial substances such as vitamins, organic acids, minerals and antioxidants that beneficially affect plants and other micro-organisms (Table 1). In agriculture, EM promotes crop growth and yield through improved release of plant nutrients, photosynthesis, resistance to plant diseases, efficacy of organic matter as fertilizers and in suppression of soil-borne pathogens and pests. The EM product also reduces offensive smells from industrial and domestic waste disposal sites, inhibits proliferation of harmful microorganisms and vectors such as flies, mosquitoes and ticks and retards the oxidation of metals.

EM is not a substitute for other management practices, rather it may be considered a compatible accompanying technology. It may be combined with other sustainable land managements such as crop rotations, use of organic amendments, conservation tillage, crop residue recycling and biocontrol of pests. In Kenya, this technology is promoted by EM Kenya for use by organic and conventional farmers. In environmental management, EM may be used to treat industrial and human wastes as it controls odors and accelerates decomposition.

Table 1. Some suggested mechanisms responsible for EM beneficial effects.

Organism	Mechanism	Effect
photosynthetic bacteria	induce root secretions	produces amino acids, nucleic acids and bioactive, substances, increases mychorrizal activity and root uptake
lactobacilli	produce lactic acid	suppresses harmful organisms in the plant rhizosphere, accelerates decomposition
yeast	excrete plant growth substances	stimulates cell division and accelerates root development

EM Technology in Agriculture

EM1_® is sold in one liter plastic bottles containing a yellow-brown liquid with an acidic pH (<4.0). This product is intended for dilution at rates from 1:100 to 1:1000 or in combination with other materials. EM may be used as a microbial inoculant for a variety of purposes in agriculture (Figures 1 and 2). It accelerates decomposition when applied to green manures prior to incorporation into the soil by ploughing (1:500) or to materials intended for composting (1:100). It may be applied as a dilute solution to irrigation water (1:1000) or to wastes for odor abatement (1:100). EM can also be applied as foliar spray (1:500) to compete with plant pathogens and as a direct soil treatment.

According to Prof. Higa, the microorganisms contained in EM promote more favorable soil microbial populations which decompose organic inputs and soil organic matter and also suppress plant parasitic organisms. Non-symbiotic microbial innoculants are relatively new to organic farming systems and show promise as a means to regulate microbial processes in the phylloplane (leaves), rhizosphere (roots) and soil. Because these processes are complex and biologically-based, the effects of EM technology are not as predictable or consistent compared to more conventional agro-chemicals, but nor are they as destructive to the environment. EM technology is considered “organic” and may be used within certified production systems. Preliminary field trials with tomatoes at Embu in Eastern Kenya suggest that a very large economic return may be obtained from spraying EM onto crops (Table 2).

Table 2. Partial economic analysis of tomato management strategies at TENRI, Embu during the 2001 long-rains (FYM indicates farmyard manure).

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Costs and returns treatment

EM fertilizer FYM control

Average yields (kg ha^-1) 87407 56111 57037 7685

Gross benefit (KSh ha^-1) 2185185 2185185 1402778 192130

Total variable costs (KSh ha^-1) 8740 157234 150459 145293

Net benefit (KSh ha^-1) 2176444 1245543 1275466 46836

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Other EM Products and Applications

Figure 1. Applying an EM solution to climbing beans using a watering can at a dilution of 1:1000.

EM extended solution is prepared by mixing EM stock, molasses and water. It is stored in an air tight container for 7-14 days to ferment until the solution attains a pH of below 4.0 and with a sweet sour smell. Its shelf life is normally 30 days after fermentation.

EM fermented plant extract is made by fermenting young fresh weeds with molasses and EM stock. It contains organic acids, bioactive substances, minerals and other useful organic compounds. By absorbing these derivatives, the plant develops antioxidants and improves its resistance to diseases. It should be applied after seedling emergency to control pests and diseases.

EM insect repellant is prepared from molasses, vinegar, distilled spirit and EM stock and stored in a tightly closed plastic container away from direct sunlight for 7-14 days. It should be used within three months after preparation by spraying a diluted solution of 1:200 (100 ml EM: 20 litres) after seed germination.

Figure 2. Applying an EM solution to young pumpkin vines using a backpack sprayer at a dilution of 1:500.

EM compost is made by applying fermented plant extract at 1:100 and sprinkling it onto a compost pile until it contains about 30% moisture. The compost is then covered and left to react for 30 to 40 days, when the compost is ready for application to the filed.

EM fermented livestock feed is made by sprinkling EM onto the feed, mixing and storing in an airtight plastic container for 10-14 days. A sweet sour smell indicates good quality silage while a rotten smell, resulting from excess oxygen, indicates poor quality. Add the fermented feed to the regular livestock feed and use within 3 months.

References

EM Technologies. 1996. The Apnan User’s Manual: EM Nature Farming Guide. EM Kenya, Embu. 139 pp.

Higa, T. and Parr, J.F. 1994. Beneficial and Effective Microorganisms (publisher not provided). 416 pp.

Higa, T. 1993. An Earth Saving Revolution. Ryukus University, Japan. 436 pp.

Editors Note. The submission by EM-Kenya was shortened somewhat at the editors’ discretion. Several other uses and claims of EM were made by the author, including those involving human health that we were not qualified to review. The crop production claims should be regarded as preliminary as no details were provided by the author concerning the experimental conditions, nor have the findings been published in a scientific journal.