South Africa Wine Technical Yearbook 2025

TABLE 1. A summary of select research into the effects of herbicide, tillage and mulches on weed control in vineyards. [(Extracted from O’Brien, F., Nesbitt, A., Sykes, R., & Kemp, B., 2025. Regenerative viticulture and climate change resilience. OENO One 59(1), as allowed by the following Creative Commons licence: https://creativecommons.org/licenses/by/4.0/.] Research focus Key findings References

Novara et al. (2011); Biddoccu et al. (2016) Kazakou et al. (2016) Kazakou et al. (2016); Hall et al. (2020); Guerra et al. (2022a) Novara et al. (2011) Celette and Gary (2013)

High soil erosion rates due to bare soil under-vine. Bare soil favoured rapidly growing weed species. Increased noxious weed species, especially ruderal species.

Challenges with conventional herbicide and tillage practices

Reduced plant biodiversity. Detrimental to ecosystem stability.

Stable weed community reduced soil erosion. Stable weed community improved water infiltration. Diverse weed communities provided essential ecosystem services. Less competition with vines. Weed community comprised of fewer noxious weed species. Increased therophyte grassland species. Straw, vine pruning cuttings, chopped pine wood, woodchip and textile mulches controlled excessive weed growth. Spent mushroom compost resulted in high weed growth due to improved soil nutrition. Straw, textile and woodchip mulches had no effect on vine growth. Improved water holding capacity and retained soil moisture in upper soil layers. Reduced need for irrigation. Summer dormant perennial grasses could be selected for low competition. Some combinations of mulch type and soil type increased native entomopathogenic nematodes. Increased soil fungi. Mulches reduced noxious weed species. Reduced extreme soil temperature fluctuations.

Benefits of a diverse herbaceous community

Kazakou et al. (2016)

Guerra et al. (2022b) Mairata et al. (2023)

Stenger and Hatterman-Valenti (2016); Cabrera-Pérez et al. (2023); Mairata et al. (2023)

Effect of mulches on weeds

Mairata et al. (2023)

Stenger and Hatterman-Valenti (2016)

Pou et al. (2021); Mairata et al. (2023) Pou et al. (2021); Mairata et al. (2023)

Mulches for climate change adaptation

Volaire and Lelièvre (2010) Mundy and Agnew (2002) Blanco-Pérez et al. (2022)

Effect of mulches on soil microbiome

resilience, and align with the broader ecological goals of regenerative viticulture. What’s next? While mulches show significant potential, further research into innovative alternatives like flame weeding, hot foam, hot air, electrical weed control or biochar-based treatments is essential. These approaches must be tested in vineyard conditions to determine their effectiveness and compatibility with RV principles. The future of vineyard weed management lies not in reverting to outdated practices, but in refining techniques that serve both the vine and the environment. To be continued… Next month, Part 3 will delve into functional biodiversity enhancement, including livestock integration in RV systems. 

like mowing or using grazing animals promote slow growing perennial species that are less competitive, including beneficial legumes like clover, which enrich the soil with nitrogen and reduce leaching. Overreliance on herbicides tends to reduce overall plant richness and can skew ecosystems toward disturbance-tolerant species, undermining long-term soil health. Table 1 summarises the impact of different weed treatments on soil health, biodiversity and vine performance. In essence, no one-size-fits-all solution exists for weed control in vineyards. But mulching, novel technologies, and thoughtfully managed ground covers all offer promising alternatives to glyphosate and ploughs. Tools that not only suppress weeds, but also build soil health, enhance

Reference https://www.wineland.co.za/rooted-in-research-what-science-says-about-regenerative-viticulture-part-2/

For more information, contact Anel Andrag at anel@sawine.co.za.

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TECHNICAL YEARBOOK 2025