The nutrient deficiencies grapevines develop in the absence of mycorrhizae, as can occur after soil fumigation, make it clear that adopting practices to encourage mycorrhizae is worth the effort. In the field, AM fungi naturally colonize grapevines. Sources of AM fungi include roots of field-propagated nursery stock (e.g. dormant benchgrafts and rootings), cover crops, and weeds, and wind-blown spores from other vineyards, orchards, and row crops. Based on the fact that mycorrhizal roots are a better source of AM fungal inoculum than are spores, an easy way to encourage mycorrhizae is to plant a cover crop.
Dr. R. Paul Schreiner, Research Plant Physiologist, USDA-ARS, Corvallis
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“MYCORRHIZAL FUNGI” - Dr. Kendra Beumgartner USDA-ARS research plant pathologist, UC Davis. Presented at Recent Advances in Viticulture and Enology (RAVE) March 16, 2006, UC Davis.
Baumgartner, K. 2003. Why and how - Encouraging beneficial AM fungi in vineyard soil (PDF). Practical Winery and Vineyard (January/February):57-60.
Baumgartner, K., Smith, R., and Bettiga, L. 2005. Weed control practices and cover crop management affect mycorrhizal colonization of grapevine roots and arbuscular mycorrhizal fungal spore populations in a California vineyard. Mycorrhiza 15:111-119.
Cheng, X, Baumgartner K. 2004. Arbuscular mycorrhizal fungi-mediated nitrogen transfer from vineyard cover crops to grapevines. Biology and Fertility of Soils 40:406-412.
Cheng, X., and Baumgartner, K. 2004. Survey of arbuscular mycorrhizal fungal communities in Northern California vineyards and mycorrhizal colonization potential of grapevine nursery stock. HortScience 39:1702-1706.
Cheng, X., and Baumgartner, K. 2005. Overlap of Grapevine and Cover-Crop Roots Enhances Interactions among Grapevines, Cover Crops, and Arbuscular Mycorrhizal Fungi (PDF). Pages 171-174 In: Proceedings of the Soil Environment and Vine Mineral Nutrition Symposium. American Society of Enology and Viticulture, 29-30 June 2004, San Diego, CA.
Cheng, X., and Baumgartner, K. 2006. Effects of mycorrhizal roots and extraradical hyphae on 15N uptake from vineyard cover crop litter and the soil microbial community. Soil Biology and Biochemistry 38:2665-2675.
Baumgartner, K. 2006. The Role of Beneficial Mycorrhizal Fungi in Grapevine Nutrition (PDF). American Society of Enology and Viticulture Technical Update 1:3.