Interrow cover crops in a semi-arid vineyard increase plant beneficial functional potential of the soil microbiome, both in vine rows and interrows, a benefit that increases with cover crop duration

Authors: INGE ROCHA, FERNANDO - University Of Oklahoma; RORIGUEZ RAMOS, JEAN CARLOS - Former ARS Employee; FERNANDO, MARGARET - Former ARS Employee; Hale, Lauren

Submitted to: Environmental Microbiome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/28/2025
Publication Date: 6/11/2025
Citation: Inge Rocha, F., Roriguez Ramos, J., Fernando, M., Hale, L.E. 2025. Interrow cover crops in a semi-arid vineyard increase plant beneficial functional potential of the soil microbiome, both in vine rows and interrows, a benefit that increases with cover crop duration. Environmental Microbiome. 20. Article 66. https://doi.org/10.1186/s40793-025-00726-1.
DOI: https://doi.org/10.1186/s40793-025-00726-1

Interpretive Summary: The use of cover crops in semi-arid perennial systems may strain scarce water resources. This study revealed that interrow cool-season cover cropping in a Mediterranean table grape vineyard conferred soil health benefits in both berms and interrows and that this impact increased with cover crop duration. Notably, in response to cover cropping plant-beneficial populations of mycorrhizal fungi increased and fungal pathogen populations declined.

Technical Abstract: Background: Cover crops are recognized for enhancing soil health and providing agroecosystem services, but are not widely adopted, particularly in water-limited regions. In Mediterranean vineyards, where water scarcity and soil degradation challenge productivity, interrow, cool-season cover cropping offers a promising strategy to improve microbial-mediated soil functions. However, the temporal and spatial effects of cover crops on vineyard soil microbiomes and soil health metrics remain poorly understood. This study evaluated the impacts of a California native (phacelia, Phacelia tanacetifolia) and introduced (rye, Secale cereale L.) plant species as interrow cover crops on soil properties in interrow and vine row soils across three years. Results: The study revealed distinct temporal and spatial dynamics in soil microbiomes elicited by the cover crop treatments. By the third year, phacelia exhibited the highest microbial biomass, fungal-to-bacterial ratios, and microbial network complexity. Interrow soils showed stronger responses to cover cropping, including enhanced microbial biomass and differentiation between treatments, while vine row soils demonstrated subtler but significant shifts in microbial metrics. Functional predictions indicated that cover crops reduced fungal pathogen prevalence and supported nutrient cycling processes. Deterministic processes driven by environmental selection became dominant under both treatments, promoting microbial resilience. Random Forest analysis identified NO3- as a key driver of microbial differentiation, with phacelia fostering communities reliant on labile organic inputs. Conclusions: This study highlights a crucial benefit of interrow cover crops in improving soil health and enhancing microbial-mediated ecosystem functions in adjacent vine row soils, even after cover crop termination. Long-term application of cover crops offers a sustainable approach to building resilient agroecosystems in water-scarce environments, with implications for sustainable viticulture practices.