Comparative assessment of four weed management strategies on soil biodiversity, vine performance, and environmental sustainability

Abstract

Among viticultural practices, Herbicide application and tillage are known to be some of the main threat for the soil biodiversity. However, these practices are the common options to date to manage weeds under the vine in the vineyard. The search for innovative and alternative practices, acceptable from a technical and economic point of view and with a more moderate environmental impact, is therefore essential to move practices towards greater sustainability (environmental, economic and social). The SOLIVITI (2021-2024) project aims to contribute to this search for innovative practices through a multi-criteria agro-environmental assessment of the impact of alternative methods for weed control. Although a focus on soil biodiversity was made, the impacts on weed flora, the agronomic performance of the vine as well as overall environmental sustainability through a Life Cycle Analysis were also monitored.

On an experimental plot located in the South West of France (Gaillac vineyard), four weed control methods were implemented and followed for four years: electric weeding, biocontrol (pelargonic acid), chemical weeding, and mechanical weeding. Soil biodiversity (microorganisms and earthworms’ abundance and diversity) was monitored at T0, before the first application of weed control method, and then annually. The results indicate that the four technical approaches have similar impacts on soil biodiversity in the short (2 weeks), medium (1 year), and long terms (2, 3 and 4 years). The four methods exhibit differences in weed management effectiveness, but the results changed over the years depending on the vintage and the weather. Similarly, no differences were observed in vine vigor, water and nitrogen status, or yield. The Life Cyle Analysis also indicates no difference in global environmental impact of the four methods, but this result must be weighed against the uncertainty surrounding the data used (biocontrol manufacturing process, terrestrial ecotoxicity of herbicides, unknown impact of electric weeding on soil biodiversity, etc.). Overall, the Soliviti project demonstrated that electric weeding or biocontrol didn’t have a specific negative effect on soil biodiversity and were similar to conventional weeding methods.

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Acknowledgments

The Soliviti project was funded by France Agrimer between 2021 and 2024 with financial support from the Trust Fund for Agricultural and Rural Development CASDAR.