Agriculture and energy sectors can benefit from Biochar technology

by Dr. R. S. Dharmakeerthi

An increasing number of global threats such as climate change, poverty, declining productivity of agricultural lands, food security, environmental pollution, energy crisis and the resulting social and political unrest appear to be overwhelming. The urgency to address these threats creates an ever increasing demand for solutions that can be implemented now or at least in the near future. To produce effects on a global scale, these solutions need to be implemented locally by individuals and through large programs.

This is a daunting task that requires many different approaches. We are fortunate to discover a single approach that has the potential to address several global issues. That is the management of our environment using biochar. It is relatively inexpensive, widely applicable, and quickly scalable in today's context.

In the late 1990's, a group of researchers discovered a black patches of soils amidst red soil in the Amazon forests.

This Amazonian Dark Earth or locally called Terra Preta de Indio is believed to be a result of the soil management practices of the Amerindians before they withdrew from these areas prior to the arrival of the European some 500 to 2500 years ago.

Natives burnt their trash piles, crop residues and debris from land clearing on the same place over and over again resulting this charcoal rich black soil. Not only were these soils fertile compared to surrounding infertile acidic soil, but also carbon dating analysis has shown that the charcoal in these soils is about 200 years old.

Biochar technology evolved based on this 'Terra Preta' phenomenon. Biochar is the solid material obtained after a thermochemical conversion of biomass under zero or limited oxygen conditions. This process is known as pyrolysis. The word is coined from the Greek-derived elements 'pyr'- fire and 'lysis'- separating.

Therefore, pyrolysis is the decomposition of organic materials by heating in the absence of oxygen. Biochar can be made using any organic material and the process also produces bioenergy.

The unique qualities of biochar, mainly the stability of carbon, high specific surface area and high charge densities, in combination with the bioenergy production could help us to solve several major global issues.

An environmentalist as well as a prominent figure in combating global warming, Al Gore, the 45th Vice President of the United States and 2007 Nobel Peace Prize Co-recipient, believes that "one of the most exciting new strategies for restoring carbon to depleted soils, and sequestering significant amounts of CO2 for 1,000 years and more, is the use of biochar .

Global warming

Due to anthropogenic activities greenhouse gasses (GHG) are released to the atmosphere at a rate faster than plants can absorb them.

As a consequence, global warming has become an undisputed fact now.

One of the main GHG is CO2 which is released mainly due to the burning of fossil fuels as an energy source. The most commonly adopted practice to reduce atmospheric CO2 concentration is to trap them in new forests.

Forest trees after they fall down however, release almost all the carbon trapped in it, due to microbial decomposition, within a decade or so under tropical conditions, contributing again to global warming. About 50 percent of carbon in trees could be converted to stable carbon forms in biochar and once applied into cropping fields these carbon will remain in the soil for centuries, if not for millennia.

Nitrous oxide (N2O) is another important GHG released in small quantities but about 300 times more harmful than CO2. Amending soils with biochar can reduce N2O release to the atmosphere.