Biochar is a vegetable charcoal that is obtained from timber or biomass through the process known by the name of pyrolysis, in which the thermochemical decomposition of materials of organic nature occurs in the absence of oxygen. In short, heat is supplied to the material to be treated, so as to create the energy necessary to break some chemical bonds within complex molecules and transform them into simpler molecules. The result is biochar, a vegetable charcoal with a carbon content up to 90% and whose compact structure makes it non-degradable by soil microorganisms, therefore it’s able to store carbon instead of returning it to the atmosphere in the form of CO2.
But why at Autosufficienza Farm are we so enthusiastic about using biochar?
It’s a soil amendment.
This means it has positive effects on the fertility of the soil in which it’s buried, improving its physical, chemical, biological and mechanical characteristics thanks to its high porosity. Moreover, it gives structure to the soil, which makes biochar of great potential to overcome some of the greatest soil limitations such as, for example, sandy soils.
By improving soil fertility, agricultural production also increases and this effect lasts for such a long period of time that it has not yet been well defined. In some Amazonian areas of Brazil, for example, there are particularly fertile plots of land thanks to the fact that the indios buried biochar in them as fertiliser a few thousand years ago.
It sequesters CO2
Greater fertility also translates into greater photosynthetic efficiency, greater biomass development and therefore greater carbon sequestration. Carbon dioxide is accumulated in the soil instead of being released into the atmosphere and this makes biochar a very useful resource for mitigating CO2 emissions into the atmosphere deriving from human activity.
It allows water saving
Its high porosity increases water retention and that of nutritional elements, which in this way remain available for plants for longer. Obviously an increase in the soil’s water capacity will entail a lesser need to irrigate crops. Moreover, its presence in the soil prevents leaching due to rain of nitrates and phosphates, preserving aquifers and the soil’s fertility itself.
It can be used to decontaminate compromised soils
An interesting property of biochar consists in the capacity to adsorb and retain persistent and carcinogenic pollutants, making it potentially useful in environmental remediation interventions, both for soils contaminated by metals and for water treatment.
It can be used for compost production
Burying in cultivated soil is not the only method of using biochar in agriculture, it in fact can also be used for compost production. According to the latest research, the addition of biochar to the composting process reduces times, greenhouse gas emissions (methane and dinitrogen oxide), ammonia losses and unpleasant odours, as well as serving as filler material for compost. On the other hand, the composting process enriches biochar with nutrients without affecting its structure.
In adequate quantities, biochar accelerates the composting process mainly by improving the homogeneity and structure of the mixture of organic materials and stimulating microbial activity (it serves at the same time as shelter and as catalyst). The temperature increase that derives from this greater activity translates into shorter compost development times.
Biochar’s porous nature means it can absorb a large quantity of water, reduce the density of the compost mass and facilitate its aeration. It will still be necessary to turn the piles, add water and monitor as usual, but the use of a small quantity of biochar can make the work a bit simpler.
Even at Autosufficienza Farm we wanted to experiment with the production of a super biochar compost. Base of manure, bran, shredded straw, yeast, sugar, ash, as the photos below demonstrate, taken on 8 May 2018. Obviously we won’t fail to give you updates in future!
For hobby uses it can be purchased in 10 kg boxes on Macrolibrarsi.it
