Biochar is a part of the Terra Preta soil and is made by burning organic material such as wood cuttings and branches. Before the coal is incorporated into the bed, it must be activated with compost, for example, so that it does not remove any nutrients from the soil. Biochar is used as a soil improver.
How is biochar made?
Biochar consists of plant material such as branches, leaves and wood. The material is burned in a kontiki kiln or cone-shaped hole in the ground and quenched several times with water when ash forms. The coal is then dried and finely ground. It is then used, for example, as part of Terra Preta or is added to the compost.
What is biochar?
Not all coal is the same. Admittedly, they are all black and porous. But biochar is apure natural substancethat existed on earth before humans. Its creation process is called pyrolysis. Plant parts(e.g. wood, leaves and grain husks) arestrongly heated (carbonized) in the absence of oxygen. What remains is the charred plant material or biochar. This was created millions of years ago during natural forest fires, but was also consciously made by the natives of South America.
The so-calledTerra Preta (black earth) of the indigenous people is a mixture of biochar and early composting (kitchen waste, dung, biomass, ash). Terra Preta made the heavily weathered soil in the tropics extremely fertile. Unfortunately, knowledge of the benefits of this agricultural method was forgotten for a long time. But in the last 40 years, biochar has become the focus of science. Biochar not only improves the soil (15 to 21 percent increase in yield), but also permanently binds the greenhouse gas CO2 in the soil.
What is the difference between charcoal, biochar and biochar?
As mentioned at the beginning, not all coal is the same. Some misunderstandings arise due to translations from English into German. In public discourse, we often come across incorrectly used terms. Biochar is scientifically differentiated from biochar. Coal is differentiated based on the raw materials, the manufacturing process, the coal properties and the area of application.
Plant Charcoal, Charcoal and HTC Charcoal – Different Charcoals with Different Purposes
Biochar
Biochar is the“umbrella term for all coal made from biomass” (Source: Biochar Association). It includes vegetable and charcoal, but also HTC charcoal. Important: Biochar initially has nothing in common with the sustainable ecological organic seal, such as organic wine. The name follows the same nomenclature as biogas or biogasoline. But there are special organic biochars that use certified organic raw materials.
Biochar
Biochar is obtained using thepyrolysis process. Biomass is heated at high temperatures in the absence of oxygen (>300 °C). The end product must then have a certainratio of hydrogen to fixed carbon to be certified as biochar. Their use lies, for example, in gardening and agriculture. In addition to wood, the starting products include garden waste, grain husks and lawn clippings.
Charcoal
Charcoal is also a pyrochar, i.e. the end product of a pyrolysis process. In contrast to biochar, the area of application is not in agriculture, but in generating heat, for example when grilling. Their starting product is wood. Because it is produced at low temperatures, harmful polycyclic aromatic hydrocarbons (PAHs) can remain. Therefore, regular charcoal (for grilling) is not suitable for use in the bed.
HTC Carbon
HTC stands for “hydrothermal carbonization” and describes a process that is fundamentally different from pyrolysis. The end product has properties similar to brown coal. Consequently, HTC carbon does not count as biochar, even though biomass is used as a raw material. Whether this type of coal is suitable for agricultural use is controversial.
Material
Biomass from agriculture, gardening and viticulture as well as from municipal collections is processed into biochar on a large scale. But your home garden also offers enough materials to make your own biochar. Old branches have proven particularly useful after green cuttings. The biomass should be quite dry.
Plant parts such as horse mackerel form the basis of biochar
The following plant parts are suitable forPlant charcoal production:
- Wood
- Lawn cutting
- Leaves
- Branches of trees and hedges
- cereal husks
How is biochar made?
What is the difference between an Easter fire and a charcoal stove? Correct! - Good mood. But the crucial difference lies in the air supply. The old fir trees on the Easter fire are intentionally layered so that as much oxygen as possible feeds the flame. In a kiln the biomass –without air– just simmers away. In order for the desired reaction to take place, temperatures must be between350 and 800 °C. If this heating takes place without air supply, then this process is called pyrolysis.
During this braising process, thelong molecular chainsof the plant cells break apart. This createssynthesis gases, heat and the porous biocharWhat took place in ineffective kilns in the Iron Age can be implemented much better today usingmodern technical pyrolysis plants: fewer emissions, better quality. Such systems are available in industrial and even small sizes for the garden. These devices help, but are not absolutely necessary. Below we will show you a method with which you can easilymake biochar yourself.
How is biochar activated?
A fresh piece of coal must not be sprinkled directly into the bed. Because it is not “charged” yet. When the long-chain molecules break up, the surface area increases many times over. One gram of biochar has an internal surface area of approximately 300 square meters. If the piece comes straight out of the kiln, very few minerals (magnesium, phosphorus, potassium, etc.) adhere to the coal. If you work it into the earth like this, the coal would remove a lot of minerals and water from the substrate.
That's why biochar must be activated before agricultural use. That means you bring them into contact with minerals. Compost is best suited for this, where the coal can soak up properly over a few weeks. In addition to minerals, water and especially helpful soil organisms such as bacteria also draw into the generous corners of the biochar.
What is biochar used for?
Biochar is not only used in agriculture
Biochar is used in the following areas of public life:
- Agriculture: as a soil additive, biochar stores water and minerals, improves the he alth of plants, binds heavy metals, nitrates and toxins and promotes soil aeration. Also great for the flower and vegetable bed in the garden!
- Livestock keeping: as a feed additive it improves animal he alth and stable hygiene, reduces the smell and also improves the manure effect.
- Communities: Biochar can be used as insulation, for decontamination, for drinking water treatment and for purification.
- Energy production: as a biomass additive and for biogas slurry treatment. Overall, more yield from biogas plants and fewer emissions.
- Industry: as a practical fabric additive, for food preservation, filler and effective against electromagnetic radiation.
- Environmental protection: Biochar binds CO2 and keeps the soil and water clean. Considered internationally as an effective negative emissions technology.
The best activated biochars
Certified biochar can also be easily purchased in high-quality, activated form at a garden center (€35.00 at Amazon) or online. We present the best biochars for the garden. We pay particular attention to sustainable production in Germany and a fair price-performance ratio. You should generally be skeptical about biochar without information about its origin.
It should also be said that biochar is not a fertilizer in itself. It serves as a soil additive that holds water and minerals in the soil. Microorganisms that adhere to the carbon need organic matter that they decompose and make available to the plants. (Organic) fertilizer additions must not be completely eliminated.
Dimicro
Dimicro's biochar is finely ground and activated, so it can be incorporated directly into the soil. As a certified organic and vegan product, it leaves nothing to be desired. Effective microorganisms improve soil quality. There are around 0.5 liters of biochar per square meter, so you can prepare around 10 square meters of soil with one order.
Carbo Verte
Carbo Verte is a special biochar activated byStinging nettle concentrate. The manufacturer recommends using it as Terra Preta, i.e. in a combination of compost, manure and primary rock powder. Alternatively, the slightly coarser coal can be placed directly underground.
The best non-activated biochars
This selection of non-activated biochars is not allowed into the garden without further ado. If it came into contact with the soil in a bed, it would remove all of its moisture and minerals. That would be fatal for the growth of the plants. Therefore, the manufacturers also show suitable options as to how their carbon can best be activated.
Miracle Garden
The organic biochar from Wundergarten promises an enormous increase in yield. It consists of medicinal plants and herbs and is very finely grained. Wundergarten also recommends mixing the biochar in the form of Terra Preta into the bed. Conveniently, the brand offers instructions for use on its website. With 25 liters, the bag is a long-term investment.
Carbo Verte
Carbo Verte again, but this time without nettle concentrate. You will receive 20 liters of high-quality biochar, which you can recharge as you wish. The manufacturer recommends sprinkling a layer of biochar on top of each layer of organic material in the compost. There should be around 10% carbon per square meter of compost. Converted to 100 liters of biochar per 1000 liters of compost.
Instructions: Make and activate your own biochar
A crucial factor in the production of biochar is temperature. It must be high enough so that harmful PAHs from the coal are burned. We therefore recommend further reading the work of the Biochar Association, which you can find here and the note from the Bavarian State Institute for Agriculture here.
- Preparing and lighting: Cut plant parts as small as possible. The drier, the better. Light a little biomass in a Kon-Tiki oven (fire bowl) or in an open fire. Make sure that as little air as possible gets to the lower layers.
- Refill: As soon as a white layer of ash falls on the biomass, continue combustion. Add two to three handfuls of new wood.
- Extinguish: When everything has burned down, completely extinguish the contents of the fire pit or oven with water. Otherwise ash will be produced instead of coal. The runoff water can be collected and used as irrigation water.
- Pouring: Pour off the water when the oven has cooled down. Make sure that fine coal is not thrown away. Therefore use cloth for sieving. Allow to dry for three to four days.
- Mortars: Finely grind the collected coarse material with a pestle.
- Activate: Activate the biochar obtained in the compost or with manure. This can take between three and four weeks.
- Incorporate: If the biochar is activated, it can be worked deep into the bed. It is best to apply mulch or a nitrogen fertilizer on top.
On the YouTube channel Sonnenerde you will find simple video instructions on how to make biochar yourself without an expensive oven.
Pflanzenkohle | Selber herstellen mit der Grubenmethode
Advantages and disadvantages of biochar
Advantages
- Stores minerals and moisture
- Provides habitat for important microorganisms
- Binds heavy metals, nitrates and toxins
- Looses the soil and improves ventilation
- Improves soil quality and plant growth
- Limishing effect – raises the pH value of the soil
- Reduces odors
- Versatile: From agriculture to water treatment
- Cheap and DIY
- Binds greenhouse gases in the soil and is considered a CO2 sink
Disadvantages
- Unactivated biochar removes minerals and water from the earth
- May contain high levels of harmful PAHs
- There are plants that react negatively to carbon/alkaline soil
- No sole climate savior
- Large use of coal is an intervention in nature (with unknown consequences?)
FAQ
What is the difference between biochar, charcoal and biochar?
Biochar is the umbrella term for all coal that is created from the charring of biomass. Charcoal is a biochar, but its area of application is the grill. Biochar can also consist of other biomass and is used - appropriately certified - as a soil additive in agriculture and horticulture.
Why do you need biochar?
Biochar was already used by the natives of South America as a soil additive. It improves soil quality and thus promotes plant growth. Biochar is also used in many areas of public life today.
How is biochar activated?
Biochar is activated in contact with freely available minerals and moisture. This can be, for example, in a compost heap or in a nettle manure.
How much biochar should you use?
About 0.5 liters of activated biochar are worked deep into the soil per square meter.
What is biochar?
Biochar is biomass that simmers at high temperatures and without any air supply. This process is called pyrolysis. Biochar has a very high proportion of carbon and functions, for example, as a soil additive in agriculture and horticulture.
How do you make your own biochar?
In order to produce biochar yourself, you first need a sufficient amount of biomass, for example annual hedge and tree trimming. This is braised in a special oven or in a fire pit, deglazed and then chopped.
