Neven
That sucks, if true. I was hoping on experimenting with this stuff in 2-3 years.
Don't give up yet. Found this great no hype overview via Google Scholar.
the scientists who work in this field seem to agree on two things. First, biochar does indeed have potential to store carbon, boost soil fertility, generate energy, and mitigate pollution. But, second, there are a hundred caveats and unanswered questions. Biochar technology, it turns out, is both incredibly simple and, as yet, somewhat enigmatic.
Biochar has great 'potential' that needs to be researched and the limitations and uses determined. There is a LOT of hype out there that is not backed up by research but at the same time it does look like many aspects of it will work out. Many of its potential valuable uses have nothing to do with agriculture.
With the right feedstock and optimal pyrolysis, biochar retains half or more of the carbon in the original biomass. And, in the soil, that carbon is remarkably stable....
...In addition to long-term carbon sequestration—and associated reduction of carbon dioxide emissions—Spokas says biochar has demonstrated “marvelous suppression” of other greenhouse gas emissions from soil, especially nitrous oxide.
So the first thing many of its promoters need to do is stop making it themselves and trying to get others to do it as well. One is likely to produce way to many pollutants otherwise (no sense making things worse) and they are wasting a huge amount of energy produced in the process that needs to be captured and used. If this ends up being suitable for sequestering large amounts of carbon it will need to be done on a large industrial scale and under stringent controls in order not to worsen pollution, etc. It is not suitable for home manufacturing.
Moreover, Lehmann calculates that the initial pyrolysis used to create biochar produces at least two to four times more energy than is used to make it, including the energy costs associated with biomass production, transport to the manufacturing site, the pyrolysis itself, and subsequent biochar soil application.
It has many potential benefits to farmers (but we do not know if it is suitable for use everywhere - chances are that it is not). Two very good things...
Biochar can have an unusually high cation exchange capacity, but also appears able to adsorb phosphate, an anion (no one knows why).
One thing that bites both ways depending on where the farmer is and his soil moisture requirements.
biochar also increases the soil’s water-holding capacity, sometimes dramatically so.
Retaining too much water might make biochar use impossible in some locations as saturated soil kills many plants and if the ground is too wet it cannot be worked either. That being said if you live in a drought prone area...
Ippolito says biochar technology potentially could be a tremendous asset for farmers facing drought conditions; they could increase soil water-holding capacity for, say, a 10-year period and also reap extra plant benefits.
The below should be a very good feature but there will likely be limitations about this aspect that provide an optimal use pattern.
Some of the big unknowns are:
We do not know if the Terra Preta was man made or a naturally occurring substance (forest fires, etc.) though it was most likely made by man.
Biochar made from different materials (wood, manure, crop waste) has different properties and some may not be suitable for agriculture use. Research needed.
Similar pyrolysis methods yield different propertied biochar. Process control is critical. Some materials require very different pyrolysis methods.
A BIG reason we need to study this a bit before jumping off into it is the following statement..
Spokas and colleagues reviewed more than four dozen biochar and black carbon studies dating from 1850 to 2011 to assess “agronomic impact beyond carbon sequestration.” Findings were inconclusive. Half of the studies reported positive effects on yield, 20% no effect, and 30% negative effects. The overall impact on yield ranged anywhere from +200% to –87%.
Large-scale biochar application would also require a compelling economic incentive for farmers. Currently, there is none.
“All the way back to the 1700s, there is literature saying that biochar would not produce the yield benefits to pay for itself,” says Spokas. “That’s a big problem.”
Regarding the above I would say that it might pay to use it on soils which are very depleted. But if we really want to use biochar to sequester carbon then that is what you do and then you give it to the farmers for free to marginally increase yields and grow a little more food. Everyone wins.
This practical, entrepreneurial approach coincides with the view from academia. Lehmann says biochar should be considered “a tool in the farm toolbox,” alongside composts, fertilizers, crop residues, and mulches. “Biochar has gained, for better or worse, some silver bullet attribute,” he says. “There is no silver bullet. There is a portfolio of options.”
The biggest users of biochar are
At the moment, most of Levine’s Biochar Solutions customers are interested in land reclamation: oil and gas producers, hard rock mining companies, and landfill owners. His second largest buying sector is the landscape services industry, and the third is split between water filtration and other industrial uses.
https://dl.sciencesocieties.org/publications/csa/articles/58/9/4
