On-farm Production and Utilization of AM Fungus Inoculum

Authors: Douds, David; Lee, Joseph - Joe

Submitted to: eOrganic
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2008
Publication Date: 12/30/2008
Citation: Douds, D.D., Lee, J. 2008. On-farm Production and Utilization of AM Fungus Inoculum. eOrganic.http://www.extension.org.

Interpretive Summary: Arbuscular mycorrhizal (AM) fungi are naturally occurring soil fungi that colonize the roots of most crop plants and form a symbiosis. Benefits to the plant include improved uptake of immobile soil mineral nutrients, water relations, and disease resistance. Given these benefits, utilization of the AM symbiosis should be an important tool in sustainable agricultural systems, especially organic systems which prohibit the use of synthetic fertilizers and pest control. This article discusses the on-farm production and utilization of inoculum of AM fungi. On-farm production of inocula avoids many costs included in the price of commercially-available inocula and could make this symbiosis, and the associated economic and environmental benefits, available to more farmers. Utilization of the inoculum in the greenhouse requires decisions relative to mixture ratio with potting media and changes to greenhouse fertilization regimes. On-farm production of AM fungus inoculum is a safe, reliable, and effective method potentially able to decrease farmers’ chemical inputs and maintain or increase yields.

Technical Abstract: On-farm production of arbuscular mycorrhizal [AM] fungus inoculum can make the benefits to crop growth and yield of inoculation with AM fungi available to more farmers by reducing costs. This article details the step by step procedure and management decisions that are needed for the on-farm production and utilization of inoculum on AM fungi indigenous to the farm. Paspalum notatum Flugge seedlings are pre-colonized by AM fungi by growing them in a media consisting of field soil from the farm and sand. These plants are then transplanted into bags containing vermiculite mixed with compost. The bags are then weeded and watered for one growing season, and the inoculum is ready for use the following spring. Instructions are given for the harvest, preparation, and use of the inoculum to produce vegetable plants for later out planting. However, even with success in the inoculum production process, utilization of the inoculum in the greenhouse requires careful management of phosphorus application to ensure colonization of the plants and to avoid rendering the inoculum ineffective.