Biochar in Agricuture
We are all aware of conventional ‘shifting cultivation’ practiced from the early days of agriculture. It is still in vogue in corners of the undeveloped, underdeveloped and developing countries including India in tribal pockets of various states where the land is utilized for cultivation only temporarily until fertility lasts and then the farmer abandons it and moves to another fertile location. As the knowledge of fertilization and other agri-inputs improved over a period of time, Agriculture is being practiced stably by farmers owning the lands and maintaining the fertility.
With many crops, ‘stubble burning’ and agricultural biomass right in the same land happens creating environmental issues like air pollution that have impact in the short and long terms. Farmers do it with a view to return some of the nutrients back into the soil ignoring other better possibilities that exist which will improve their income as well as the environment by producing BIOCHAR which is the topic of discussion today. This article is aimed at creating awareness in the farming tribals in corners of the country and benefit from it. It is not meant to be a general article without deeper technical details and discussions.
What is Biochar? It is a carbon rich solid that is derived from any sort of biomass, produced under oxygen limiting environment, technically called as Pyrolysis. Normally, in the locations where tribals live abounds in natural and cultivated biomass use of which is inefficient; either it is burnt in the open or it rots. Communities there can convert it into Biochar, forming a cooperative and trade it through reliable agencies and achieve multiple benefits.
Conversion of Biomass into Biochar is not a difficult process and can be done in a small space by farmers individually and pool it for collective trading. Depending on the scale of production, if large, infrastructure undergoes sophistication; we are not discussing at large industrial production in this article. I suggest an inexpensive top lid, updraft system which can be made very easily. Biomass is chipped into small pieces, filled in a 200 liter steel drum with holes made in the bottom and sides towards bottom, cut the top of it, say couple of inches from the top end, cut it open from the centre of the lid into star shape and lift the flaps up in such a way that a smaller open drum fitting exactly on the top of the bottom drum (to allow the fumes to escape), fill it with chips, light the fire in it and cover it with a smaller open drum which acts as a chimney. In this system, we are not allowing the oxygen to enter it freely; we are allowing only the fumes to escape. As the top chips burn, they create heat at the bottom too converting the biomass into biochar and keep releasing smoke that escapes through the top chimney. Within a couple of hours (which needs to be standardized based on the size of the chips put in), the process is completed. Water needs to be sprayed on the top as well as the sides of the drums, the contents are removed and allowed to cool spraying water on the freshly produced biochar and stored. One can make several cycles per day in this manner and also increase their production using several units.
Let us see some of the several benefits of Biochar.
- Biochar has a very long shelf life, virtually hundreds of years! By converting the biomass into biochar, we are making the biomass completely resistant to bacterial /fungal attacks, reduce the carbon emissions into the environment. It is in fact, a mechanism to permanently sequester carbon that is fixed by the plants to reduce carbon dioxide escape into the environment. In the cooperative set-up, one can attempt to get carbon credits as well. This is however possible only if large enough production is done and documented by a coordinating agency involved in international carbon trading.
- Biochar has immense pore space in its porous anatomical structure and can harbour soil nutrients and soil microorganisms. Though it is not a fertilizer itself, due to this structure, biochar applied to the soil stabilizes pH, improves the soil fertility making available nutrients and beneficial microbiota.
- Nature of biochar differs based on the source material utilized, processes followed thus influencing the final product and quality.
- Biochar applied to soil controls leaching of the nutrients to lower strata of soil and make them available to the plants.
- Biochar is the basic raw material for production of ‘Activated Charcoal’ that has several applications in pharmaceuticals, scientific research, nanotechnology etc.; we shall deal with it in another article.
Importance of Biochar has now been internationally recognized and being traded and also branded based on raw material used giving specifications. For the philanthropically inclined companies and NGOs, it provides an opportunity to create an avenue and improve the lot of the disadvantaged farming and tribal communities and arrive at a win-win situation.