April 25, 2005                                                                                           Joe Nunez, Farm Advisor

Vegetable Crops/Plant Pathology

661-868-6222

BENEFITS OF MYCORRHIZAL FUNGI

            Arbuscular mycorrhizal fungi are specialized fungi that form symbiotic relationships with most plants.  The fungus benefits by getting sugars from the plant while the plant sees improved growth.  Mycorrhizae improve plant growth by several different means.  One way is increasing the root surface area thus increasing the ability to pick up water and soil nutrients, especially nonmobile nutrients such as phosphorous and zinc.  Mycorrhizae are also beneficial in helping the plant root system be more resistant to soil borne diseases.  Mycorrhizal plants generally have increased growth and yield because of these varied benefits. 

            Because of the benefit of mycorrhizal symbiosis, there is an interest on how agriculture can manipulate this system.  Comparison of mycorrhizal fungal diversity will allow the determination of possible effects that agricultural practices such as fungicides and fertilizers may have mycorrhizal fungal populations. 

            A survey was conducted in Kern County to help determine the diversity of the indigenous mycorrhizal fungi in vegetable production.  Three conventional vegetable fields, three organic vegetable fields, and three non-cultivated native areas were included in the survey.  Surprisingly, only two species, Glomus intraradices and Glomus mosseae accounted for almost all the mycorrhizal diversity in Kern County.  A third unidentified species accounted for a small portion of the total. 

            Generally speaking, there were more mycorrhizal fungi in the non-cultivated native soil than the organic vegetable fields and even fewer in the conventional vegetable fields.  Apparently the more agricultural inputs applied, the fewer mycorrhizal fungi will be present.

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