Though biochar use in the soil prompts many questions, it also seems to carry some benefits.
Since black carbon such as biochar degrades slowly, it’s bound to remain in the soil over a long period of time providing the much needed soil carbon.
Due to it’s long lasting nature, biochar could keep on being replenished with nutrients from the soil, fertilizers or compost to release them slowly to the crops.
Application of biochar together with a nutrient source is an innovation that could lead to efficient use of fertilizers.
But this long lasting nature also creates opportunity for useful microorganisms to colonize biochar pores and boost soil fertility.
Biochar in the soil could also curb conversion of biomass into fossil fuels.
REDUCTION OF AIR CARBON
The reason why some environmentalists tout biochar as a sensation is simply because carbon is more useful in the soil than in the air.
Picture a subsistent farmer in sub Saharan Africa thinking of how to utilize extensive crop waste in his farm.
Two possibilities might spring up:
Convert the waste into charcoal for fuel or into biochar for soil application.
(Biochar differs from charcoal only on application).
If the farmer chooses the charcoal way, more carbon would be pumped into the atmosphere.
But on the other hand, if he chooses to apply it to the soil, less carbon would be released into the atmosphere.
This way, conversion of farm waste into biochar could mitigate against climate change.
But agricultural driven climate change could also be tackled in another way.
REDUCTION OF NITROUS EMISSIONS FROM FERTILIZERS & MANURES
Among the major crop nutrients, nitrates are perhaps the most slippery because they can easily be lost to the atmosphere.
Just leave a mound of manure in the open and notice the gradual reduction of volatile gases (stinky smell) over time as a result of nitrous emissions.
The same truth holds for nitrates in mineral fertilizers, crop remains and in compost.
But when such nitrate-rich matter is mixed with biochar, the extensive porous network attracts and ‘holds onto’ the nutrients over time.
This is advantageous in two ways:
First, the nutrients are not lost through leaching (percolating through the soil) or through the air.
They are made available to the crops.
But secondly, the vaporization of nitrous gases is suppressed.
This is very significant because nitrous oxide is one of the more potent greenhouse gas which leads to elevation of surface temperatures.
Biochar carries with it unexploited opportunities which need to be unearthed.
But as we do so, we must seek sustainability because without it our effort will be in vain.