Wednesday, May 16, 2007

Agrichar: In the news May 15th

Two short articles well worth the read for terra preta enthusiasts:

Carbon project raises hopes: Waikato Times, NZ:

...Structural biologist Alfred Harris, process engineer Wolfgang Weinzetll and two Tauranga entrepreneurs are involved in Ecotechnology Ltd, which is working to reduce fertiliser use without hampering plant growth. The company is investigating producing a charcoal product from forestry and other organic waste which collects unwanted nutrients...

Recent work by Australian researchers showed wheat gained an additional $A96 per hectare in value when charcoal was banded in the soil with mineral fertilisers.

Is banded C the killerapp for agrichar? I don't know what the charcoal application rate was, but last I knew, banding equipment had limited material application capacity, charcoal is low density, and there was mineral fertilizer in the hopper also. A charcoal application rate in the neighborhood of about 100 lbs per acre seems reasonable to expect. At $100/ton for charcoal, material cost would be $5/acre ($A15/hectare). Is the value in comparison to a no-C comparison? I would surely like to see the research.

Seeder image source: Flickr by IRRI Images

Another May 15 article

Special Report: Inspired by Ancient Amazonians, a Plan to Convert Trash into Environmental Treasure (by Scientific American) has a great soil point-counterpoint under the heading: But is it viable? :

As with all new technologies, many questions about the ultimate utility of agrichar have yet to be answered. "As of now agrichar is not a uniform product," explains John Kimble, a retired USDA soil scientist. "And there's no easy way for farmers to apply it with existing equipment. They also need to know there is a large enough source of the material. Farmers are driven by profit, as is everyone, and they need to be shown that it will improve their bottom line."

Complicating debates about the costs of agrichar is the paucity of data on the subject. "No one is sure what types of biomass should be used as raw material," Kimble notes, "or exactly what production methods work best, so calculating the costs is really an exercise in speculation."

In addition, scientists are finding it hard to replicate the original terra preta soils. "The secret of the terra preta is not only applying charcoal and chicken manure—there must be something else," says Bruno Glaser, a soil scientist at Bayreuth University in Germany. Field trials in Amazonia using charcoal with compost or chicken manure find that crop yields decline after the third or fourth harvest. "If you use terra preta you have sustaining yields more or less constantly year after year," he says.

"I'm skeptical about adding just a pure carbon source," says Stanley Buol, a professor emeritus from the Department of Soil Science at North Carolina State University's College of Agriculture and Life Sciences who spent 35 years studying Amazonian soils. "It will be black and look good," but will it contain enough inorganic ions, such as phosphorus and nitrogen, essential to plant growth?"

Many of the interactions between the char, the soil and the microorganisms that develop with time and lend the soil its richness and stability are still poorly understood. Glaser believes that the key to making agrichar behave like terra preta lies in the biological behavior of the original Amazonian dark earths—a difference he attributes to their age. "You would need 50 or 100 years to get a similar combination between the stable charcoal and the ingredients," he cautions.

"I think [research into the biological behavior of terra preta] is where the new frontier will be," Lehmann counters. If he is right, and scientists can perfect a modern-day recipe for agrichar, then its fans will not need Richard Branson's $25 million to jump-start their initiative—the annual demand for fertilizers exceeds 150 million tons worldwide.
There are strong indications that soils amended with high (multiple tons/acre) rates of biochar need considerable time to reach their optimum. For setting where return on investment cycles need to be short, lower rates sustained for long periods of time may make more sense as a strategy for building soil C.

Monday, May 14, 2007

Soil conference on non-CO2 gas emissions

Researchers at the University of Melbourne are holding a conference to discuss the importance of greenhouse gas emissions from soils.

A major concern is nitrous oxide from fertilizer, manure and biomass applications.

"300 times more potent than CO2, so even small emissions of this non-CO2 gas can make a considerable contribution to global warming” says Dr Stefan Arndt.

“When nitrogen is added to a wheat field as fertilizer or added to a pasture through animal faeces or clover swards, a part of the nitrogen can be lost as nitrous oxide, and when the weather conditions are right this can lead to large emissions of nitrous oxide” says Dr Eckard.

...not widely known [is] that soils can actually [take] methane out of the atmosphere. “Forest soils are especially efficient at taking up methane” says Dr Livesley.

At the present time there is not much knowledge about the magnitude of these non-CO2 emissions...

(revised May 18, 2007:)It is interesting that non-CO2 GHGs, like nitrous dioxide (NO2), aren't more in the news, considering their potential impact and (for NO2) a fascinating pattern of anthropogenicity.

Image source: Greenhouse gases, by

edit: revised intro to N02 map - yet again as my level of understanding evolves

Sunday, May 13, 2007

Agrichar future

In a post earlier today: Mental Rut, Back40 takes Johannes Lehmann, soil scientist, and terra preta front man, to serious task for cheer leading the politically attractive aspects of TP:

Agrichar should not be crufted up with political baggage or tainted by association with the various climate hysteria inspired carbon wheezes. That it sequesters carbon in a more durable form than forests or other organic forms is a plus, but not its primary value. It is just one of the multiple benefits of agrichar. That fact should not be lost in a blaze of hype. It's the wrong message.
Back40's comments make good sense. Consider that terra preta has serious political problems in the offing. Charcoal production as a tool to combat global warming can be understandably counterintuitive. Char's mode of action in the soil is only partly understood, the degree of benefit to the soil is not well documented. Claimed char additions may be difficult to monitor.

Various blog and forum posts ask: Does the fuel value of charcoal provide a dangerous incentive to divert agrichar to fuel use? To overharvest biomass? Can the reality of terra preta nova be separated from marketing pitches by commercial pyrolysis interests?

In this environment, poor marketing choices will hurt the prospects of terra preta. We terra preta advocates need to distinguish our advocacy for improved soil from our advocacy of commercial pyrolysis and of char carbon sequestration. The value of char as a soil amendment can, and must, stand on its own merits. Only successful implementation of terra preta nova in stand alone and market driven settings can validate the fundamental benefits of biochar.

The agricultural value of charcoal is competing well with its fuel value at a market price of about $100/ton. Agrichar doesn't appear to need carbon sequestration subsidies, and at $4 a metric ton CO2, maybe it isn't even worth the paperwork.

Charcoal is fairly simple, and generally profitable to produce. The pyrolysis process used to produce char is adaptable and scalable. It can be used to co-generate heat, nitrogen fertilizer, hydrogen fuel and/or electrical power, indicating ample incentives to increase charcoal supply capacity. Rising fuel prices seem certain to increase the supply of charcoal.

The price of charcoal is driven mostly by its value as fuel. Coke, originally derived from coal to replace charcoal, cost about $100/ton in late 2006, which seems to also be about the same price as charcoal at the time. Significant quantities of charcoal are used in Japan for agriculture at these market prices.

Proponents of terra preta hope to speed adoption by subsidizing it with carbon credits. Currently CO2 sequestering goes for about $4 per metric ton on the carbon credit market. Carbon dioxide units at full molecular weight can be converted into carbon units by dividing by 44/12 (see endnotes here). Thus the carbon credit value of amending soil with charcoal is currently $14.67 per metric ton, or $13.31 per ton. This could be a nice kicker but the soil amendment value of charcoal, at $100/ton, is the significant component.

Note: Image from Flickr by carlosjwj (Location: Korogocho, Nairobe)

Saturday, May 12, 2007

Soil is a living system.

Like Snow
Originally uploaded by bones4.
Soil behavior fundamental to soil performance requires a living component. Remove the life from soil and it can be argued that what remains is no longer soil. It remains not-soil until it is reinoculated, repopulated, and restored to a living system. For all but the harshest land surfaces on our planet, soil life "reboots" faily easily.

Other names consistent with not-living "soil" are dirt, regolith, buried soil, and soil fossil. Another term, earthen material, encompasses both soil and not-soil.

An interesting discussion is whether there can be lunar soil or martian soil. While life currently appears absent, the surface of lunar and martian regolith does appear to have been sufficiently transformed by solar energy flux to qualify as a candidate soil. Since life is all about energy flux, perhaps our current concept of soil as a living system will ultimately be replaced with a concept of soil as an energized system.

Reposted from Yahoo Answers.

Simpler Way To Counter Global Warming Explained: Lock Up Carbon In Soil

The techniques of ancient American Indians who used charcoal in their soil to keep them fertile (Terra preta) are being married with modern engineering. More here:

read more | digg story

Added: I came across this story on digg and noticed the blog-it tab...

Wednesday, May 09, 2007

Biofuel demand pencils out to damaged soil

Crop residue is not a waste. It is a precious commodity and essential to preserving soil quality.

Production systems must be developed so that ethanol produced must be at least C neutral if not C negative. Temptations [to mine soil vitality] aside, biofuels produced from crop residues may neither be free nor cheap.
Rattan Lal, SSSA President, has a timely message to his fellow Society members in the May issue of CSA News (regretfully subscription only). It is that we must take this opportunity to break the cycle of soil destruction that characterizes the rise and fall of civilized man. Biofuels adds unprecedented value to biomass production. Rattan Lal sketches out the numbers, comparing potential demand to crop residue available. With demand tracking above supply, the temptation is to mine the soil of its vitality. Rattan Lal observes that soil exploitation is the primary contributing factor to desertification.
Harvesting crop residues for use as fodder for livestock, residential fuel for cooking and heating, construction material, and other competing uses is a reality in sub-Saharan Africa, South Asia, China, and other developing countries. Therefore, it is not surprising that these are also the regions that have been plagued with severe problems of soil degradation.

With a severe decline in physical quality, degraded soils do not respond to fertilizers even if made available at a subsidized price. Adverse effects of none or low rates of applications of fertilizers and other amendments on agronomic production and soil quality have been exacerbated by the perpetual and indiscriminate removal of crop residues coupled with uncontrolled and excessive communal grazing.

The stubborn trends of low crop yields and perpetual hunger and malnutrition in sub-Saharan Africa and in regions of rainfed agriculture in South Asia cannot be reversed without returning crop residues to the soil and also supplementing them with liberal applications of other biosolids.
Rattan Lal has done an admirable job in this appeal to the his fellow SSSA members. He has included constructive comment on tools and processes available to make biofuels production compatible with maintaining soil vitality. But the undercurrent message is that those of us who love soil must involve ourselves in the process, the policy, and the public discussion of our transition to sustainable energy.

Leave comment or email me if you would like to request a copy of Rattan Lal's May address. Or better yet, join SSSA.

Tuesday, May 08, 2007

Carbon Sequestration for Farm, Forest Income

The New York Times has an article about selling carbon credit through the Chicago Climate Exchange (CCX).:

An acre of pine forest captures and holds one to two metric tons of carbon dioxide per year, which it uses for photosynthesis. Untilled cropland holds a third of a ton of carbon per acre, and rangeland holds up to a fifth of a ton. The sequestered carbon dioxide is measured by soil tests before and after the planting.

Carbon dioxide credits now sell for about $4 a metric ton. Mandatory restrictions, experts say, could increase the price to $12 or higher. In Europe, the cost of a credit sold for sequestering carbon dioxide has reached $20, and even $30, a ton.
The market for carbon credits seems to hover between $3 and $4. A review of past CCX newsletters reveals sporadic volume, with common fluctuations of $0.50 to $0.75 per metric ton per month. The New York Times article suggests that biological sequestration will ultimately be replaced with geological sequestration. Expectations of sustaining $20 or $30 a ton seem unrealistic.

$3-$4 is far better than the $0.25 that the Confederated Tribes of the Colville Reservation in Washington received for forested land in the 1990s.

The Tri-Societies' science policy blog has a post about Farming Carbon:
Currently, farmers who wish to profit from the sequestration potential of their soils can sell carbon credits on the (CCX).
Science is needed to better quantify the carbon flux and carbon sinks.
At present, aggregators don't attempt to gauge the carbon impact of individual farms nor do they quantify counterbalancing emissions of traces gases. Hopefully, ASA/CSSA/SSSA members can play a constructive role in the CCX, providing the scientific basis on which aggregators will improve their climate accounting.
I would like to see more discussion on the nuts and bolts of accounting and verification.

Flickr Source: George sampling 3/2/07 ESA Common

Sunday, May 06, 2007

Agri Char Conference Reviews

Agri-char aka bio-char is the key ingredient in soil scientists' holy grail, terra preta nova (my previous mention). Initial reports from participants at the first meeting of the International Agrichar Initiative indicate continued hope that agrichar amended soils could contribute significantly to our planet's health and productivity.

Kelpie Wilson, Truthout's environment editor, writes:

Charcoal's pores also make excellent habitat for a variety of soil microorganisms and fungi. Think of a coral reef that provides structure and habitat for a bewildering variety of marine species. Charcoal is like a reef on a micro-scale.

Over at the Sydney Peak Oil forum, attendee burko writes:

It would be very easy to become enthusiastic about the future of these integrated technologies. However, there is one overriding impression of this field to keep in mind – it is brand, spanking new. So new that even the choice of name Agrichar is being debated. There are no books; there are few years of experience even amongst the researchers; the debates about the benefits to AGW are only just beginning.

In short, being a part of the conference could be compared to hearing an orchestra tuning up. There are skillful cellists and masterful tuba players preparing next to each other. The idea is potential for beautiful music, rather than cacophony. We aren't really sure who the conductor is yet – plenty of skillful people are taking part of that role. There is cooperation and the desire to share experience at all points – but this is a new kind of orchestra.

While the soil biology alone is a staggering subject, we should be as interested in the methods of producing the black carbon. Burko writes on pyrolysis:
The gas produced is referred to as syn gas, called producer gas sometimes.

My formative understanding of the process says something like this – if you want to produce non-activated chars, temperatures need to be constrained below the levels that gasification requires in order to make the reaction sufficiently exothermic to be self sustaining.

Of course, there is more to it than that – I did find that combustion engineers found it difficult to provide a simpler explanation.

I did get one useful figure from Dr Robert Brown, from Iowa State University – if you're burning wood in an open fire, you're probably only getting a third of the heat energy that should be possible from gasification – a pretty compelling reason to try and understand this stuff. It's been said that up to a third of the worlds deforestation happens in the name of inefficient cooking fires.
From the reports, it is clear that the number of players, and their diversity, is growing exponentially. One reason for this diversity is that the process of making terra preta nova appears to be as adaptable to a wide range of soils and climates as it is scalable. You can have regional collection and distribution approaches coexisting with processes adapted to individual enterprises. The plan at Fourth Corner Nurseries (mentioned previously) near Bellingham, WA is a great example of both points. The operation already amends the soil with char. Observed better root growth confirms what we already sense, that black carbon can have a positive effect on a wide range of soils. The nursery plan to use surplus biomass from their willow coppice field to power the nursery and to produce char is easier said than done, but is brimming with promise.

Image: Scanning electron micrograph of a conductive carbon sticky tab. (Flickr - St Stev)