Managing agricultural waste
The most efficient farmers will collect as much of this agricultural residue as possible and try to make use of it. Leftover straw from grain can become livestock feed or bedding for the stables. A portion of the residual wood from a rubber farm might be sold off as firewood.
In many parts of the world, however, and especially in the tropics, the systems are not in place to handle so much waste effectively, and the quantities of biomass are unmanageable. Consequently, vast quantities of waste remain in the field to rot, or worse, the piles are simply burned and reduced to ash.
These solutions – if they can even be called that – have a disastrous environmental impact. When left behind to rot, the agricultural remnants will slowly decompose and release carbon dioxide and other more dangerous greenhouse gases, including methane and nitrous oxide. These are among the most serious contributors to climate change. Even worse, a massive bonfire can eliminate the waste far more quickly, but release all those emissions in one calamitous outburst. The plumes of smoke affect the air quality in ways that are obvious to the eyes and the lungs, without the need for rigorous scientific data.
Biochar for waste management
As an alternative to slow decomposition or rapid incineration, turning waste biomass into biochar results in a product that is incredibly valuable for improving the soil. Through the process of pyrolysis, essentially cooking the biomass at a very high temperature in an oxygen-deprived environment, you can produce a charcoal-like substance that serves as a substitute for fertiliser.
While conventional fertilisers effectively deliver nitrogen, phosphorus and potassium (NPK) to the roots of your plants, biochar actually improves the conditions in the soil surrounding the roots, leading to a much healthier overall ecosystem without such a need for those expensive fertilisers.
The microscopic nooks and crannies on the biochar create an enormous surface area that acts like a sponge, attracting millions of beneficial microbes that keep the soil teaming with life. Additionally, biochar helps with moisture retention in the soil, reducing the need for irrigation. Healthy and well-balanced soil also needs fewer additives in the way of pesticides and fungicides.
Farmers have been making use of biochar in different ways for thousands of years, through slash-and-burn agriculture and by dumping the burnt coals from their fireplaces into their gardens. But only recently have gardeners and agronomists really come to appreciate the serious merits of this simple additive.