Indigenous Microorganism 4 (IMO 4) as a Soil Inoculant

Abstract

Since 1997, many farmers across the world have adopted techniques of an agricultural system called Natural Farming, which utilizes indigenous microorganisms and naturally derived soil amendments to improve soil dynamics and plant production. However, due to a dearth of peer reviewed reports that exist on the subject, many stakeholders and researchers have been hesitant to use these agricultural techniques. The most widely discussed and utilized Natural Farming amendment is Indigenous Microorganism 4 (IMO 4), which is a form of indigenous microorganism inoculated compost made from agriculture by-products, high in carbohydrates, and a moderate concentration of plant available nutrients. Because of this lack of scientific data discussing IMO 4 as a soil bio-stimulant, a series of experiments were designed and implemented to analyze the physical, chemical, and biological properties of IMO 4, as well as examine the effect of IMO 4 on soil dynamics and growth of corn (Zea mays) in Andisol soil, when compared to other organic amendments. It was determined that IMO 4 was rich in indigenous microorganisms and possesses an appreciable concentration of plant available nutrients. The physical, chemical, and biological analyses of IMO 4 indicated a potential as a soil bio-stimulant if the indigenous microorganisms survive inoculation. A greenhouse experiment comparing IMO 4 to organic matter applications showed IMO 4 had a similar effect on soil dynamics and growth of corn as the application of organic matter. A further experiment examining the effect of IMO 4 in conjunction with organic fertilizers showed that IMO 4 had similar impact on soil dynamics as organic matter amendments, due to the substrate effect of IMO 4 applications. Organic matter amendment applications also showed a significantly greater effect to plant height, dry weight, and total leaf area than the IMO 4 samples. There was no evidence the indigenous microorganisms on the IMO 4 substrate survived inoculation into the soil environment. It was concluded that IMO 4 was effective in adding organic matter and plant available nutrients to the soil via a substrate effect. Due to the lack of effect IMO 4 applications have on plant growth and the absence of significant improvement to plant production, organic matter amendment applications in the form of composts and mulch are recommended.