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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Molecular Characterization of Foodborne Pathogens Research » Research » Publications at this Location » Publication #305419

Title: On-farm production of arbuscular mycorrhizal funus inoculum in compost and vermiculite mixtures: results of on-farm demonstrations and impact of compost microbiological quality

Author
item Douds, David
item CHAIYASEN, AMORNRAT - Chiang Mai University
item VASQUEZ, LOIDA - Rodale Institute
item WERTHEIM, FRANK - University Of Maine

Submitted to: Journal of the National Association County Agricultural Agents
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/13/2014
Publication Date: 12/2/2014
Citation: Douds, D.D., Chaiyasen, A., Vasquez, L.R., Wertheim, F.S. 2014. On-farm production of arbuscular mycorrhizal funus inoculum in compost and vermiculite mixtures: results of on-farm demonstrations and impact of compost microbiological quality. Journal of the National Association County Agricultural Agents. http://www.nacaa.com/journal/index.php?jid=444.

Interpretive Summary: Arbuscular mycorrhizal [AM] fungi are naturally-occurring soil fungi that form a beneficial symbiosis with the roots of most crop plants. This symbiosis enhances soil nutrient uptake, disease resistance, and drought tolerance. Better utilization of the symbiosis through inoculation with AM fungi should increase farm sustainability and profitability and allow for reduction of synthetic chemical inputs. Earlier, researchers at the ERRC cooperated with The Rodale Institute to develop a method for farmers to grow AM fungi on-the-farm for use in vegetable production. This method uses compost mixed with readily-available greenhouse potting media ingredients in a ratio defined by the nutrient content of the compost. We conducted experiments to 1) demonstrate the inoculum production system on working farms and 2) determine if the system’s compost mixture ratio is affected by whether the compost is dominated by fungi or bacteria. The on-farm inoculum production system produced approximately 300 units of AM fungi per cubic centimeter, averaged over 40 trial runs. Furthermore, biological status of the compost did not significantly affect AM fungus production. These results demonstrate the reliability of the on-farm production system and its potential to be an alternative to purchased forms of the fungi.

Technical Abstract: The sustainability and profitability of many agricultural systems can be enhanced through the utilization of inoculum of arbuscular mycorrhizal fungi. Inocula are commercially available, but inoculum can also be produced on-farm in mixtures of compost and vermiculite with a nurse host plant. Demonstration of the on-farm system at a network of cooperating farms produced inocula with an average potency of 297 ± 43 propagules of AM fungi cm*** (mean ± SEM, n= 40 site years). Spread of colonization in host roots was greater for bacterial- vs. fungal-dominated compost, but compost dilution ratio with vermiculite was a more important determinant of AM fungus spore production than compost type.