ON-FARM PRODUCTION AND UTILIZATION OF MYCORRHIZAL FUNGUS INOCULUM

Authors: Douds, David; Nagahashi, Gerald; Pfeffer, Philip; KAYSER, W. - STONELEIGH ESTATES; REIDER, C. - THE RODALE INSTITUTE

Submitted to: Canadian Journal of Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2004
Publication Date: 5/3/2005
Citation: Douds, D.D., Nagahashi, G., Pfeffer, P.E., Kayser, W.M., Reider, C. 2005. On-farm production and utilization of mycorrhizal fungus inoculum. Canadian Journal of Plant Science v.85. pp.15-21.

Interpretive Summary: Arbuscular mycorrhizal [AM] fungi are beneficial soil fungi that enhance the growth and health of crop plants. Efficient utilization of these naturally occurring fungi would enable farmers to both apply less fertilizer and potentially increase crop yields. A variety of these fungi are available for purchase commercially, but their use in large-scale agriculture may be cost prohibitive to farmers in developing countries. Therefore, several methods have been developed whereby farmers can produce their own inoculum of these fungi. This report is a summary of methods developed in Columbia, India, and by the USDA in Pennsylvania. Target farms in the tropics are small, labor-intensive farms while those in Pennsylvania are vegetable farmers who produce their own seedlings for transplant to the field. Each of these methods has been demonstrated to produce AM fungi that resulted in increased yields when applied to root and vegetable crops.

Technical Abstract: Arbuscular mycorrhizal [AM] fungi colonize the roots of the majority of crop plants, forming a symbiosis that enhances nutrient uptake, pest resistance, water relations, and soil aggregation. Inoculation with effective isolates of AM fungi is one way of ensuring the potential benefits of the symbiosis for plant production. Although inocula are available commercially, on-farm production of AM fungus inoculum would save farmers the associated processing and shipping costs. In addition, farmers could produce locally adapted isolates and generate a taxonomically diverse inoculum. On-farm inoculum production methods entail increasing inoculated isolates or indigenous AM fungi in fumigated or unfumigated field soil, respectively, or transplanting pre-colonized host plants into compost-based substrates. Subsequent delivery of the inoculum to the field presents technological barriers that make these methods more viable in labor-intensive small farms. However, a readily available method for utilization of these inocula is mixing them into potting media for growth of vegetable seedlings for transplant to the field. Direct application of these inocula to the field and transplant of seedlings precolonized by these inocula have resulted in enhanced crop growth and yield.