Grower Adherence to Legume Cover Crop Rhizobia Inoculant Maintenance and Use Recommendations in the Southeast.

Grower Adherence to Legume Cover Crop Rhizobia Inoculant Maintenance and Use Recommendations in the Southeast

Suzanne Fleishman¹, Julie Grossman², Erika Larsen² and Sarah Bowen³

Organic growers often use legume cover crops in their rotation to take advantage of symbiotic biological nitrogen fixation by rhizobia bacteria in root nodules. Rhizobia are may be added to the seed at planting, a process called inoculation, to increase the number of rhizobia in the root zone and consequently the degree of nitrogen fixation. Although a variety of resources explaining the most effective inoculation practices are available from agricultural extension and manufacturers, little is known about which, if any, of these practices are implemented by growers. This study addresses this issue by exploring grower inoculation practices.  Information was gathered from voluntary surveys distributed at conferences and email lists with a target population of organic growers in the Southeast.  The survey focused on cover crop choice, inoculation approaches, inoculant care and maintenance, information sources, and farm demographics. The growers' responses were compared with the most recommended practices by extension, manufacturers and the literature. Results suggested that 41% of growers choose inoculants based off of recommendations from the seed vendor, but obtain information about what practices to follow nearly equally from the seed vendor (25%), inoculant vendor (22%), organic online information (18%), and the seed package (23%).  Furthermore, it was found that only 55% of growers surveyed follow recommendations of storage temperature practices of 40 F and 26% follow the most highly recommended application practices, of using a sticky agent other than water with solid inoculant. Unexpectedly, new growers (less than three years of experience) who likely have the greatest need for inoculation, regularly inoculate the least. From these observations it was concluded that in a majority of cases growers do not follow the practice that is most highly recommended for inoculation success. Proper practices could be increased and implemented with greater outreach to growers through workshops and publications.

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