Evaluating the diversity of soil microbial communities in vineyards relative to adjacent native ecosystems

• Vineyard land use influenced the structure of soil microbial communities.
• Soil pH differences between land uses correlated to bacterial community variation.
• Differences in land use plant diversity correlated with all fungal communities.
• Temperature, CEC and soil texture correlated with communities, for all land uses.
• Abiotic and biotic conditions explained less community variation than expected.

Agricultural land use disturbs soil microbial communities, which can reduce crop production and impair ecosystem functioning. We investigated the effects of viticulture on the diversity and composition of three soil microbial communities: bacteria, fungi and arbuscular mycorrhizal fungi, by comparing communities in vineyards and nearby unmanaged areas. All three communities were influenced by land use. Bacteria had higher species richness in vineyards whereas arbuscular mycorrhizal fungi had higher richness in unmanaged areas. Differences between vineyards and unmanaged sites in community composition for the three microbial groups were related to both abiotic and biotic factors. In particular, bacterial communities were most sensitive to soil pH, whereas fungal (including AM fungi) communities responded more to changes in plant diversity. Other abiotic factors (cation exchange, temperature and soil texture) were correlated with community compositional changes, regardless of land use. These results indicate that viticulture practices influence key factors controlling soil microbial communities and possibly affect nutrient availability and other services provided by natural soil communities.