Evaluating nature-based solutions for under trellis soil management: effectiveness and impacts on vine performance compared to conventional strategies

Abstract

Soil management plays a key role in climate change adaptation. Despite weed-grapevine competition for resources can be reduced through tillage and herbicide use, novel nature-based solutions (NBS) are explored as an alternative and more sustainable viticultural practice. Studies demonstrated that ecosystem services can be achieved with conservation techniques such as native vegetation, planted cover crops and row middle mulching. However, it’s still unclear if these benefits can be extended to the under-trellis area through NBS adoption. The goal of this study was to identify under-trellis cover crops (CC) that exhibit reduced water use and limited biomass growth compared to native vegetation, while also effectively covering soil and controlling weeds. Their impacts on physiological and agronomical parameters were also evaluated. Four under-trellis treatments (H–herbicide, NV–native vegetation, GH–G.hederacea, TS–T.subterraneum) were compared in a mature commercial Vitis vinifera cv. Italian Riesling vineyard in Oltrepò Pavese (IT). Treatment implementation started in 2022 while inter-row native vegetation was established from vineyard planting.  H was included as a low-competition control (two glyphosate sprays), NV as a high-competition control (repeated mowing) and TS and GH as alternative low-maintenance NBS treatments. Measurements done in the 2024 growing season included seasonal variations of soil coverage (%), above-ground CC biomass (LAI and dry matter/m^2) and soil evapotranspiration rate (ET) using a portable closed chamber. Concurrently, assessing grapevine performance: leaf gas exchange, yield and grape composition at harvest, and canopy growth after leaf fall. Lastly, a preliminary assessment of treatment effects on grapevine root distribution up to 80 cm of depth was done. TS showed a decreasing soil coverage trend while NV peaked. H plot soil was maintained vegetation free, and GH under-trellis soil was consistently fully covered. These trends were associated to different CC ET rates (never higher than ET rate of NV). At veraison, both GH and TS treatments showed improved vine’s physiological performance compared to NV (A – μmol/m2 – 10.7 and 10.3 respectively vs 8.1; gs – mol/m2s – 0.26 and 0.25 vs 0.18).

Further understanding current results of underground interactions between vines and under-trellis CC, describing roots distribution across soil depth and evaluating the effects on soil water potential is required.