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Submitted to: Practical Winery and Vineyards
Publication Type: Trade Journal Publication Acceptance Date: 7/17/2002 Publication Date: 1/1/2003 Citation: Baumgartner, K. 2003. Why and how: encouraging beneficial am fungi in vineyard soil. Practical Winery and Vineyards. Interpretive Summary: Arbuscular mycorrhizal (AM) fungi are beneficial organisms that have a close association with the roots of a variety of plants, ranging from corn to redwoods. They've been shown to increase crop yield and nutrient uptake, enhance resistance to plant pathogens, and to stabilize soil structure. Research on AM fungi and grapevines in both the greenhouse and the field shows that mycorrhizal vines have greater shoot and root growth when compared to non-mycorrhizal vines. AM fungi occur naturally in vineyards worldwide. When land is cleared for vineyard establishment, AM fungal spores and roots from mycorrhizal hosts that previously inhabited the site serve as inoculum for grapevines. AM fungi also occur on the roots of field-propagated nursery stock. There are things you can do to encourage AM fungal populations in your vineyard. Plant a cover crop. Most vineyard cover crops are hosts of AM fungi (with the notable exception of mustard). Maintenance of cover crops during the winter results in a higher concentration of AM fungal spores in vineyard soil. Plant a cover crop mix. Cover crop mixes are likely to encourage a greater diversity of AM fungal species, which may increase the chances of encouraging those that are best for vines in your soil. Mow the cover crop in spring instead of incorporating it. Soil disruption breaks up mycorrhizal networks. Plant with field-grown nursery stock. Vines raised in the field have AM fungi in their roots. Adopting practices that encourage AM fungal populations is easy, since these beneficial fungi naturally colonize grapevine roots. However, these practices should not be substituted for nutrient amendment, irrigation, or pest management, especially when deficiencies or diseases/pests are already widespread in the vineyard. Technical Abstract: Arbuscular mycorrhizal (AM) fungi are beneficial root inhabitants that have a mutualistic symbiosis with the roots of a variety of plants, ranging from corn to redwoods. Research on AM fungi and grapevines in both the greenhouse and the field shows that grapevines exhibit a positive growth response when inoculated with AM fungi. AM fungi occur naturally in vineyards worldwide. When land is cleared for vineyard establishment, AM fungal spores and roots from mycorrhizal hosts that previously inhabited the site serve as inoculum for grapevines. AM fungi also occur on the roots of field-propagated nursery stock. Indigenous AM fungal populations in vineyards can be maximized by planting cover crops. Most vineyard cover crops are hosts of AM fungi (with the notable exception of mustard). Maintenance of dormant season cover crops increases AM fungal spore populations. Cover crop mixes are likely to encourage a greater diversity of AM fungal species. A diverse AM fungal community may be more capable of providing grapevines with consistent benefits across a broad range of soil conditions. No-till cover crops are preferrable to tilled cover crops. Soil disruption breaks up mycorrhizal networks. Adopting practices that encourage AM fungal populations is easy, since these beneficial fungi naturally colonize grapevine roots. However, these practices should not be substituted for nutrient amendment, irrigation, or pest management, especially when deficiencies or diseases/pests are already widespread in the vineyard. |
