Wood Vinegar: An Effective Natural Alternative to Synthetic Herbicides Such As Glyphosate

Introduction

The widespread use of glyphosate as a herbicide has raised environmental and health concerns, leading to regulatory scrutiny and restrictions in various regions. Consequently, there is growing interest in environmentally friendly alternatives. One such alternative is wood vinegar, a byproduct of biomass pyrolysis. This study examines the herbicidal effects of wood vinegar on nitrophilous plant communities under natural conditions.

Experimental Design and Application

Wood vinegar (WV) derived from pine biomass was tested in field conditions at the Royal Botanic Gardens of the University of Alcalá, Spain. The experiment consisted of four treatment groups:

  • Low concentration (25% WV)
  • Medium concentration (50% WV)
  • High concentration (100% WV)
  • Control (no treatment)

Each treatment was applied to 1×1.5 m plots in April, the natural sprouting season. WV was applied once using a standard backpack sprayer at a rate of 0.8 L/m² in 8 plots and 1.6 L/m² in 4 plots. The study monitored biomass reduction, plant cover changes, and species composition over 42 days.

Key Findings

Biomass Reduction

  • All WV treatments significantly reduced plant biomass within seven days, with reductions exceeding 70%.
  • By day 42, WV-treated plots had four times less biomass than control plots.
  • No significant differences were observed between the 25%, 50%, and 100% WV treatments, suggesting that a 25% dilution may be sufficient for effective weed control.

Plant Cover and Succession

  • Initial plant cover decreased by over 75% in all WV-treated plots within the first week.
  • Over time, perennial species replaced annual weeds in treated plots. By day 42, perennials occupied 80% of the treated plots, compared to 30% in control plots.

Species-Specific Sensitivity

  • Species with smooth leaves and lighter stems were most affected.
  • Bromus spp., Calendula arvensis, and Geranium molle experienced nearly complete eradication.
  • Perennial species such as Medicago sativa and Cynodon dactylon showed increased cover by the end of the study period.

Microscopic Observations

  • Electron micrographs revealed severe epidermal damage within hours of WV application, particularly in stomatal cells.
  • Plants with protective structures, such as waxy cuticles or trichomes, exhibited greater resistance.

Implications

The results highlight WV as a promising contact herbicide with potential applications in sustainable weed management. Its ability to suppress annual weeds while allowing perennial species to thrive suggests potential use in ecological weed control strategies. However, the regulatory framework for WV as a herbicide remains unclear, necessitating further policy developments.

Conclusion

Wood vinegar demonstrates effective herbicidal properties, significantly reducing biomass and altering plant community composition. A 25% dilution appears adequate, though variability in results suggests the need for further optimization. Given its natural origin and environmental benefits, WV could serve as a viable alternative to synthetic herbicides, pending regulatory approval.

Article based on: Herbicidal Effects of Wood Vinegar on Nitrophilous Plant Communities