Wood Vinegar

What is Wood Vinegar

Wood Vinegar

Wood vinegar is the by-product of charcoal production (a slow pyrolysis¹ of wood).

 In the process of making charcoal, smoke from the charcoal kiln vents is released to the atmosphere by using chimney or flue pipe.

When passing through chimney or flue pipe, the smoke cooled down by the outside air and condensate into pyroligneous acid, particularly when the temperature of the smoke is in range between 80-180ºC, acrid and yellowish.

This happened when the wood in the kiln is in the exothermic decomposition process (spontaneous breakdown of wood structure), between 270°C - 400°C.

¹Pyrolysis is a thermochemical decomposition of organic material in a closed system at elevated temperature and in the absence of oxygen in the air.

Small scale wood vinegar and charcoal production in Thailand

Modern research of the use of wood vinegar had been carried out since the early of 1950’. In the last 15 years, interest in wood vinegar resurfaced as people started to question the safety and effectiveness of agro-chemicals. 

It is now widely used by farmers in Japan, Taiwan, Korea and Thailand. However, it is still not widely known or accepted by Malaysian farmers.

“It is neither a fertilizer nor an agro-chemical. Yet when it is correctly applied, it enhances the intake of fertilizers and reduces the damages by various diseases. Wood vinegar enhances rooting, helps in the regulating of the nutrients condition of the soil, and the balance of the microbiological population. The changes in the microbiological population not only greatly reduce the tendency of soil bound diseases, it also increases the vitality of the roots and hence enable better uptake of nutrients” as reported by Steven Leong in his article for A Growing Culture.

What’s in Wood Vinegar


It is estimated that wood vinegar contains more than 200 components. These include:

• Alcohol (methanol, butanol, amylalcohol)
  
• Acid (acetic, formic, propioinic, valeric)
  
• Neutral substances such as formaldehyde, acetone, furfural, valerolactone
  
• Phenols (syringol, cresol, phenol)
  
• Basic substances such as ammonia, methyl amine, pyridine
  

What Can I Do With Wood Vinegar:

• Repel nematodes – Tomatoes, 1:100 (apply to the base of plants); strawberries, 1:200 (apply to the base of plants); and black pepper vines, 1:1500 (apply in place of water).

• Repel insect pests - Cabbage and Chinese cabbage, 1:500 (apply in place of water); corn 1:300 (spray onto leaves).
  

• Control of fungal diseases – Tomato and cucumber, 1:200 (spray onto leaves).
  

• Control of root rot – Tomato and cucumber, 1:200 (apply to the base of plants).

• Reduce incidence of chili pepper flowers aborting – 1:300 (spray onto leaves).
  

• Improve flavor of sweet fruits and stimulate development of crops. Mix solution rates of 1:500 to 1:1000. Wood vinegar prevents excessive nitrogen levels, improves plant metabolism and contributes to higher fruit sugar levels.
  

• Stimulate compost production. A solution rate of 1:200 will help increase the biological activity of various beneficial microbes and can decrease composting times.
  

• Combat bad odor. A wood vinegar solution of 1:50 will diminish the production of odor-causing ammonia in animal pens.
  

• Supplement for livestock feed. Mixed with livestock feed at rates of between 1:200 and 1:300, wood vinegar can adjust bacterial levels in the animal digestive tract which improve the absorption of nutrients from feed.
  

• Enrich garden soil. Use a strong solution of 1:30 to apply to the garden soil surface at a rate of 6 liters of solution per 1m² to enrich the soil prior to planting crops. To control soil-based plant pathogens, use an even stronger rate of 1:5 to 1:10.
  

• Repel houseflies. Dilute wood vinegar at a rate of 1:100 and apply to affected areas.
  

How Does It Work

As reported by Steven Leong, wood vinegar has bactericidal effect at high concentration because of its high acidity, methanol and phenol content. However, it has the ability to propagate microbes as well. It kills nematodes directly and can propagate microbes that feed on them.
This is mainly due to the effect on the metabolism by its main element, acetic acid. Acetyl co-enzyme is produced by plants and microbes from acetic acid. Through the TCA cycle, acetyl co-enzyme is converted into citridic acid, malic acid, fumaric acid, succiric acid and other elements that are necessary for the plant and microbes.


On leaves surface, foliar spray of wood vinegar changes the acidity of the leaves surface and deter the propagation of the pathogenic bacteria and some bacteria are killed by direct contact. It also induce the plant to produce bio-chemicals to increase in resistance of the leaves against pests and diseases (Induced Systemic Resistance)


Gibberellin, cytokinin, auxin, etherlene and abscisic acid are the 5 types of plant natural hormone that are closely related to the growth and health of a plant. Etherlene and abscisic acid contribute to the plant’s resistance against diseases and attacks from bacteria.

In the event of excessive intake (application) of nitrogen, the formation of etherlene is reduced. But on the other hand, growth hormones like gibberellin, cytokinin and auxin will be produced. As a result, the size of the plant increases but the resistance against diseases is reduced.

This can be corrected by using wood vinegar. Due to its acidity, wood vinegar accelerates the process of transformation of the excessive nitrogen into amino acids. This will also stabilize the formation of methionine, a type of amino acid that affect the production of etherlene. As the result, oxidized etherlene is also produced. These processes contribute to higher plants resistance against various diseases.

Through foliar spray, the leaves of the plant become shinier and darker in colour because of the increase of chlorophyll content due to the effect of the ester in the wood vinegar, which promotes photosynthesis. This ester also helps in the formation of sugar and amino acids, which make the produce tastier, healthier and stronger resistance against pests and diseases.

The Drawbacks


Wood vinegar is slightly toxic to fish and plants if applied excessively.



References:
1.An Introduction to Wood Vinegar, by Rick Burnette, ECHO Asia Notes, Issue 7, Oct 2010.
http://www.echocommunity.org/

2. The Use of Wood Vinegar In Reducing The Dependence On Agro-Chemicals, by Steven Leong

http://www.agrowingculture.org/