Locally Effective Microorganisms: Increasing Nutrient Use Efficiency of Organic Amendments through Changes in Microbial Community Structure.

Up to 50% of nutrients applied to agricultural fields can go unused by crops and are lost to the environment through leaching, runoff and volatilization. Increasing nutrient use efficiency in cropping systems is vital to addressing this issue. Farmers in parts of the developing world have pioneered the use of Local Effective Microorganisms (LEM) to help manage pests and to enhance the microbial richness of disturbed agricultural soils and maintain soil health. LEM is a concentrated solution of locally derived microorganisms produced using partially decomposed leaf litter mixed with carbohydrate rich substrates. In spite of its extensive use in some parts of the world, scientific data on LEM’s effect on the soil is lacking. The objective of this study is to better understand how applying LEM affects the cycling of mineral nutrients in compost production as well as in forage and legume systems. Our three treatments include LEM applied along with an organic amendment specific to the crop being cultivated, a false-LEM applied with the organic amendment and the organic amendment applied alone. We are examining nematode assemblage structure and nitrogen availability over time as well as assessing forage and legume quality. This study is being carried out both in Monteverde, Costa Rica, as well as in Watkinsville, Georgia - allowing us to explore two, distinct ecological systems in which to observe the effect of these locally derived microbial inoculums.