Produced locally in Port Townsend, biochar is a major low-hanging fruit with regards to carbon sequestration, being an extraordinarily stable form of that element. It is essentially a shortcut to achieving long-term carbon-rich soil, and it is produced in Port Townsend as a byproduct!
What is Biochar?
Biochar is essentially charcoal, but made with an eye to optimizing its use in agriculture rather than its energy content, and can be made with a broader range of materials, such as crop residues or manures as well as wood. Like charcoal, it is made by burning wood or other organic material under conditions of low oxygen, a process called pyrolysis.
Biochar is a particularly recalcitrant (stable) form of carbon. With half-life estimates ranging up to 1,000 years, it is ideal for carbon sequestration.
In terms of physical attributes, biochar is black, highly porous, lightweight, fine-grained and has a large surface area. On average, about 70 percent of its composition is carbon, though this varies quite a bit. The remaining percentage consists of nitrogen, hydrogen and oxygen among other elements. Its precise chemical composition will vary according to the feedstocks used to make it and methods used to heat it.
In the Soil
Biochar may be a relatively inert form of carbon, but it ends up increasing the life in the soil. The porosity and high surface area of biochar creates desirable habitat for life-promoting soil microbes.
Because of the capillary action arising from that porosity, as well as a high cation-exchange capacity, the biochar attracts water and nutrients to itself, allowing excess water to be absorbed by the soil and preventing nutrients from being leached away. This means that water and nutrients are available to the plants during dry periods, lowering both water demand and the need for chemical fertilizers.
Many scientists, especially citizen scientists, have experimented with growing plants with and without biochar in the soil. The general consensus is that soils with biochar grow bigger, more nutrient-dense plants, and grow them faster, while using less water and amendments over time.
Because biochar attracts water and nutrients to itself, initially it will be competing with plants for those nutrients -- if uncharged. Charging is the process of infusing the biochar structures with plant nutrients before it is worked into the soil. There are many ways to charge biochar. These are a few of the most commonly mentioned...
1. Add it to your compost while it is being made -- up to 10% by volume of raw material. It will be charged by the time the compost is finished. Added benefits: it speeds up the composting process while reducing its emissions of greenhouse gases.
2. Biochar can also be added to finished compost, at a rate of up to 50% by volume. This should sit for a week or so before being incorporated into the soil.
3. Use it in the barn, adding it to the animal bedding. Added benefit: odor control, ammonia absorption, reduced nutrient leaching and improved pathogen control. When the bedding is spent, the whole urine-soaked manure/straw/biochar mix can be added to the compost.
4. Fill a garbage can or other container with raw biochar, then add until covered a dilute mixture of one or more of the following: a) fish emulsion; b) worm tea; c) compost tea; d) a slurry of animal manure(s); e) urine; f) seaweed extract; g) powdered mineral rock dust. A diverse selection of charging agents is almost certainly better than one. Adding a handful of humus-rich soil from the garden can also be helpful for introducing microbes. Let it sit -- anywhere from 5 days to 3 weeks. There are no set guidelines here.
5. In autumn, in areas where plants have died back and no winter crops are planned, it may be possible to spread raw biochar directly on the ground, with other soil amendments, to be naturally charged by the time spring planting time arrives.
Here in Port Townsend, we are blessed with an incredible opportunity to make use of the carbon-sequestering and soil restorative properties of biochar. The Port Townsend Paper Company (PTPC) makes biochar as a byproduct! If not diverted to other uses, it is simply burned for fuel.
This biochar is a byproduct of a steam combustion boiler at PTPC, which means that the heat produced in the production of the biochar is used in mill processes, rather than simply being wasted. This is called a "combined heat and biochar" process and is, unfortunately, not how all biochars are produced. Carbon dioxide is released when organic matter is burned for biochar, so unless the generated heat is used to displace combustible fuels, the carbon balance of the whole operation will be far from optimal.
Another big advantage of this biochar, of course, is that it is local.
The biochar made at PTPC is available to the public through Olympic Biochar (OB), a private company with an exclusive contract to distribute the product. Olympic Biochar resells it at very reasonable prices compared to other sources. Early on, OB had the biochar third-party tested to make sure it meets the certification requirements of the International Biochar Initiative (IBI). It does.
In terms of pollutants, OB biochar tests quite clean: no measurable PaHs or PCBs; dioxins and the long list of other chemicals tested for are all below recommended maximum levels. The testing also ascertained that the carbon content of this biochar is a substantial 80% which makes it all the better for carbon sequestration. Its particle size is smaller than most, which makes it easier to mix with soil or compost. Its pH is 8.2 which makes it helpful in acid soils. There is also very little ash compared to biochar from crop debris or manure.
Unfortunately, OB biochar is not, and cannot presently be, certified as organic, since one third of its feedstock is construction debris (the remainder is waste wood chips from logging operations). The construction debris used by the mill is primarily chipped pallets, and has been certified not to contain treated wood or lead-based paints. Contaminants in the feedstock are primarily staples and bits of sheet plastic. The biochar itself tests clean, but the organic certification process is based on process rather than end product.
The Biochar Program
of the Olympic Carbon Fund
The Olympic Carbon Fund (OCF) is working with Olympic Biochar (OB) to reroute as much biochar as possible from the paper mill to local soils. Eligible applicants can receive a cubic yard of OB biochar for free, and up to three additional sacks for half price ($75). Farms, large food gardens, foresters, soil restorers and private homes on acreage all may be eligible to receive a whole cubic yard, depending on the Fund balance. Individual home food gardens are eligible for the Bucket Share program.
In the Bucket Share program, people on an email list will receive notice of pop-up Bucket Share events. While the bag lasts, emailed sequesterers will be able to show up and help themselves to two or three 5-gallon bucketfuls of biochar. Once that biochar has been charged and worked into the soil, the person will be eligible for more.
Olympic Biochar bags its product in one cubic yard "super sacks" which help prevent the biochar from blowing or washing away as it is being gradually taken out and worked into the soil. OCF-approved clients can arrange to have their super sack picked up in Chimacum by anyone with a pickup or trailer. Charging the biochar is the responsibility of the recipient.
When considering quantities, a good rule of thumb would be one cubic yard of biochar for every 500-2000 square feet of planting area, depending on how deep the biochar is worked into the soil. Biochar can be added incrementally, year by year. It does the most good in the root zone of the plants.