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Saturday, November 6, 2021

Biochar testing and use in Tablas Creek's Regenerative Farming practices

Tablas Creek has a nascent Biochar study program whose testing regime extends beyond those recounted in my prior writings. The Tablas Creek Biochar experience was uncovered partly through posts on its world-class blog (Tablas Creek Blog) and partly during the course of my interview with Jordan Lonborg, the estate's Viticulturist.  I visit Tablas Creek's testing and use of Biochar in this, my final post on Tablas Creek's Regenerative Organic Certified quest.

Biochar is a charcoal-like substance resulting from burning organic and forestry waste at high temperature (450 - 750 degrees C) in an oxygen-free environment -- a process called pyrolysis. During pyrolysis, the organic material is converted into biochar (a stable form of carbon that cannot easily escape into the atmosphere), biofuels (such as bio-oil and synthetic gas), and residual heat. The technology, its benefits and disadvantages, and its applications are discussed here.

Tablas Creek ran a trial which incorporated 10 tons of biochar into other materials in order to determine the impact of its use on crop growth. The materials and conditions are illustrated below. The only external inputs in this test were the biochar and the cover-crop seeds. The compost was made on the property and the manure was the result of three-days of effort (in an enclosed space) by the estate's sheep herd which had been fed with feed harvested from the property.

As illustrated above, the cover crops were "happy in all rows" but the biochar-compost mix (isolated by the red border) had a "cover crop that was considerably taller than the rest of the blocks."

In the blog, Jordan wrote both about the simplest application of biochar for small producers as well as Tablas Creek's plans in the area. In terms of the small producer, Jordan recommends placing the biomass (in their case grapevine prunings, fallen logs, and brush) into a receptacle and lighting it in such a manner that the material burns from top to bottom. The top-to-bottom burning allows (Lonborg):
  • Gases in the biomass beneath the fire to combust and burn off
  • Almost all the carbon is left behind
    • If done properly, very little CO₂ is released into the atmosphere
  • Residual of a nearly pure form of carbon (biochar).
Jordan is a proponent of the onsite production of biochar as a viable alternative to burn piles which pollute the air and release "massive amounts" of CO₂ into the atmosphere. As far as Tablas Creek's plans were concerned:
  • They wanted to replace purchased biochar with biochar produced in a small kiln which would be designed and deployed on property
  • Canes not used in the composting process would be used as feedstock for the biochar program; as would be any wood collected on the property
  • Any biochar produced on the property would be incorporated into the compost.
During the course of our discussion, I queried Jordan as to the biochar state of play at Tablas Creek. He indicated that they were creating biochar both in a pit and a kiln, the latter a repurposed 1000-gallon wine tank. They are still in the process of figuring out the best materials for use as biomass as well as the best sources of those materials. He has arrived at the conclusion that canes are the best for them but also recognizes that uniformity of size of input materials is key to maximizing the amount of material produced. The kiln allows them to burn deeper into the season as well as the capability of a terminate-on-demand feature with the attachment of a water source.

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While biochar figures prominently in the Regenerative Agriculture literature (and maybe even in some early ROC writings), it is not directly mentioned in the current ROC specifications. It goes unmentioned in both the major Regenerative Practices and the sub-category Other Regenerative Practices. It could be tangentially referenced in the practice described as Recycling of Onsite Biomass or in the following note at the base of the Other Regenerative Practices category: "Producers may use the ROSP to propose site-specific regenerative practices successfully implemented in their unique location and will be approved on a case-by-case basis."


©Wine -- Mise en abyme

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