Exceptional results from biochar experiment in Cameroon

Key Farmers Cameroons coordinator at a plot in Ediki, in which the difference between char and non-char maize was exceptionally big. In this case, the plants on the control (left lower corner) were barely in their 8th leaf stage, whereas the plants on the char-plots (right, upper corner), were already tasseling. Photo credit: Laurens Rademakers, Etchi Daniel-Jones. Source: biocharfund.org.

Key Farmers Cameroon's coordinator, Etchi Daniel-Jones, at a plot in Ediki, in which the difference between char and non-char maize was exceptionally big. In this case, the plants on the control (left lower corner) were barely in their 8th leaf stage, whereas the plants on the char-plots (right, upper corner), were already tasseling. Photo credit: Laurens Rademakers, Etchi Daniel-Jones. Source: biocharfund.org.

Biochar Fund has reported extremely encouraging first results from its field trials in South West Cameroon. Working with small groups of subsistence farmers around the town of Kumba, the Fund set up and managed a large-scale experiment to assess whether maize (corn) yields were improved by the addition of biochar to the soil. The biochar was made from local agricultural wastes and tree thinnings. The data from the trials strongly suggests that biochar adds greatly to food production. Some areas showed yield improvements of more than 250% over the control plots. The areas dosed with biochar also showed substantially increased production of crop biomass, including roots, stalks, and leaves.


Many field studies in the tropics carried out by academic researchers have shown that biochar improves soil productivity. (For more details on what biochar is and how it is made, see an earlier article on this site, here.) Biochar Fund’s research did more. It showed that poor farmers typically making less than $300 a year from their crops were able to improve their own yields using simple techniques both for making the char and adding it to the soil. Average production of maize from this area of Cameroon is about 1.7 tonnes per hectare compared to about 7 to 9 tonnes in the EU or US. If the initial results are replicated elsewhere, the impact of biochar could see yields increase by 40% above what would otherwise be obtained.

Biochar Fund research techniques
The experimental methods seem robust. A large number of small groups, comprising 10 to 30 members, were asked to participate. They cultivated 75 test areas across very different soil types, including weathered, degraded land as well as productive volcanic plots. Each area was asked to plant 12 sub-plots, 4 without biochar, 4 with biochar applied at 10 tonnes an acre, and 4 with 20 tonnes an acre. Each type of plot was then divided into areas without any fertiliser, with organic-only fertiliser, with artificial fertiliser, and with both types of fertiliser together. The fertiliser was applied at the rate usually used in the research area. (Because of a shortage of money, many areas would usually not have fertiliser applied.)

The biochar was made in a low-technology kiln using agricultural wastes from the previous harvest and some wood cut back from trees surrounding the cultivated areas.

The farmers sowed seed densely and harvested the corn when it was ready. They weighed the whole plant, including roots, the cobs, and also the grain itself. Some of the groups did not produce usable results because the grain was stolen (‘because it looked so good’ report the affected farmers) or because of pest damage or because of misunderstandings about how to apply the methodology. But 41 of the 75 test plots yielded data on biomass weight and slightly fewer on grain yield.

The results
The principal results from the experiment are as follows:

  • a) Adding biochar at the rate of 10 or 20 tonnes a hectare typically added about 85% to the weight of grain produced compared to the adjacent plot with no fertiliser.
  • b) This is about the same increase as would be gained by adding both organic and artificial fertiliser to the unfertilised soil. So biochar is as effective at increasing yields as heavy application of fertiliser.
  • c) If both biochar and two types of fertiliser are added, the yield rises to an average of about 140% of the level without any additions. Biochar therefore substantially increases the food production of land above what would be achieved either with or without added fertiliser.
  • d) It seems as though the most striking results are found on the poorer soils.

Full data analysis is here and in PDF form on the data page.

These results are preliminary but they show the powerful benefits that biochar might bring to food availability in many tropical soils. Getting heavy doses of char into the soil will be demanding but the great advantage of biochar may be that it only needs to be applied once and its effects persist for decades. The results from the second maize sowing of the year (to be harvested in the next few weeks) will show whether the yields improvements continue.

The implications of the research
The beneficial results from the application of biochar on degraded tropical soils are now too frequently reported to be a statistical artefact. Biochar works. The remaining opponents of biochar focus on the dangers of using native forests as the source for the combustible material. If biochar is so good at improving yields, they say, then forests will be cut down to improve soils. The Cameroon results show that this should not be the case. Here are some numbers from the experiment:

  • Applied at 10 tonnes a hectare, biochar added about 4.5 tonnes a hectare to the total biomass, excluding the food grains, of unfertilised land.
  • One tonne of organic matter will typically produce about one third weight of biochar – say 1.5 tonnes a hectare.
  • So the weight of biochar added to the soil (10 tonnes/ha) will be repaid in increased biomass production (not just food) within about 6-7 years.
  • Therefore, if one seventh of the land has biochar added for seven years the net biomass availability by the end of this period will be higher, prospectively for ever if biochar permanently increases yields.
  • There should therefore be very limited pressure to cut down forests to make biochar – biochar can be made from the incremental biomass produced on the land to which it has been applied.
  • This conclusion would be even stronger if we took into account the fact that some areas, such as parts of Cameroon, can produce two crops a year. Payback would be twice as quick.

The most important result from this remarkable experiment in Cameroon may be that it lays to rest the worry that biochar will exacerbate deforestation. In fact, by increasing biomass production biochar should reduce the need to cut down trees for fuel.


The experiments in Cameroon will continue. Biochar Fund (www.biocharfund.org) is also running several other trials. Here is an excerpt from its recent email:

Given your continued interest in biochar research, we are glad to keep you up to date on our activities in the future. These activities include a large project in the Democratic Republic of Congo, which is aimed at reducing the deforestation rate resulting from slash-and-burn farming; a project that aims to build highly integrated agroforestry farms which protect biodiversity and ecosystem services; and the development of a novel cocoa drying technology which coproduces biochar.

If I may give a personal view, I think these research projects are among the most important in the world today. Please consider giving your support to Biochar Fund and Key Farmers Cameroon in whatever way you can.

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  1. Erich J. Knight’s avatar

    Thank you Chris for featuring the Biochar Fund’s great work

    Another significant aspect of bichar and aerosols are the low cost ($3) Biomass cook stoves that produce char but no respiratory disease. http://terrapretapot.org/ and village level systems http://biocharfund.org/ with the Congo Basin Forest
    Fund (CBFF). The Biochar Fund recently won $300K for these systems citing these priorities;
    (1) Hunger amongst the world’s poorest people, the subsistence farmers of Sub-Saharan Africa,
    (2) Deforestation resulting from a reliance on slash-and-burn farming,
    (3) Energy poverty an a lack of access to clean, renewable energy, and
    (4) Climate change.

    In the US;

    Senator Baucus is co-sponsoring a bill along with Senator Tester (D-MT) called WE CSHAR. Water Efficiency via Carbon Harvesting and Restoration Act! It focuses on promoting biochar technology to address invasive species and forest biomass. It includes grants and loans for biochar market research and development, biochar characterization and environmental analyses. It directs USDI and USDA to provide loan guarantees for biochar technologies and on-the-ground production with an emphasis on biomass from public lands. And the USGS is to do biomas availability assessments.
    WashingtonWatch.com – S. 1713, The Water Efficiency via Carbon Harvesting and Restoration (WECHAR) Act of 2009


    Biochar Soils…..Husbandry of whole new orders & Kingdoms of life

    Biotic Carbon, the carbon transformed by life, should never be combusted, oxidized and destroyed. It deserves more respect, reverence even, and understanding to use it back to the soil where 2/3 of excess atmospheric carbon originally came from.

    We all know we are carbon-centered life, we seldom think about the complex web of recycled bio-carbon which is the true center of life. A cradle to cradle, mutually co-evolved biosphere reaching into every crack and crevice on Earth.

    It’s hard for most to revere microbes and fungus, but from our toes to our gums (onward), their balanced ecology is our health. The greater earth and soils are just as dependent, at much longer time scales. Our farming for over 10,000 years has been responsible for 2/3rds of our excess greenhouse gases. This soil carbon, converted to carbon dioxide, Methane & Nitrous oxide began a slow stable warming that now accelerates with burning of fossil fuel. Agriculture allowed our cultural accent and Agriculture will now prevent our descent.

    Wise Land management; Organic farming and afforestation can build back our soil carbon,

    Biochar allows the soil food web to build much more recalcitrant organic carbon, ( living biomass & Glomalins) in addition to the carbon in the biochar.

    Every 1 ton of Biomass yields 1/3 ton Charcoal for soil Sequestration (= to 1 Ton CO2e) + Bio-Gas & Bio-oil fuels = to 1MWh exported electricity, so is a totally virtuous, carbon negative energy cycle.

    Biochar viewed as soil Infrastructure; The old saw;
    “Feed the Soil Not the Plants” becomes;
    “Feed, Cloth and House the Soil, utilities included !”.
    Free Carbon Condominiums with carboxyl group fats in the pantry and hydroxyl alcohol in the mini bar.
    Build it and the Wee-Beasties will come.
    Microbes like to sit down when they eat.
    By setting this table we expand husbandry to whole new orders & Kingdoms of life.

    This is what I try to get across to Farmers, as to how I feel about the act of returning carbon to the soil. An act of penitence and thankfulness for the civilization we have created. Farmers are the Soil Sink Bankers, once carbon has a price, they will be laughing all the way to it.

    Dr. Scherr’s report includes biochar. http://www.worldwatch.org/node/6124

    I think we will be seeing much greater media attention for land management & biochar as reports like her’s come out linking the roll of agriculture and climate.

    Unlike CCS which only reduces emissions, biochar systems draw down CO2 every energy cycle, closing a circle back to support the soil food web. The photosynthetic “capture” collectors are up and running, the “storage” sink is in operation just under our feet. Pyrolysis conversion plants are the only infrastructure we need to build out.

    There are dozens soil researchers on the subject now at USDA-ARS.
    and many studies at The up coming ASA-CSSA-SSSA joint meeting;

  2. Mike’s avatar

    Excellent article – you are totally right about this kind of biochar field trial being one of the most important projects in the world today. It has the potential to increase crop yields for some of the most poverty stricken peoples in the world.

    I see the main virtue of these projects as educational for the individual farmers and communities involved. They can simply see the improved yields in their crops and on the basis of self preservation alone will continue charring their fields for generations to come.

    Spreading these ‘research’ projects over large geographical areas will help seed the spread of knowledge through these people.

    At the end of the day they aren’t interested in field trial results in academic literature, global warming, carbon cycles or any of the other issues that we see – they simply want to know that next year they will have food to eat.

  3. Laurens’s avatar

    Thank you for this excellent article, Mr Goodall.

    Mike, allow me to respond to you. We have experienced that the farmers are indeed most interested in immediate gains in food output.

    But they do have a very great interest in learning about issues like climate change and biochar – even the most simple peasant shows a strong thirst for knowledge. Our participants were absolutely amazed to hear that something like global warming is actually going on, and to our own surprise, they were quite apt at understanding something as complex as the (agricultural) carbon cycle. They are enthusiastic about the idea that they can play a role in mitigating climate change. It makes them proud, in a sense. And you know what? The words “carbon credit” are the talk of town here. So it’s not just food, the other things matter too, to them.

    Our only real problem is to make sure that some form of carbon compensation actually reaches them. Because that would make biochar a really interesting farming concept to them. If you make $200 a year, a carbon credit of $30 is a big help.

    It is really fantastic to sit down with some farmers in a tiny village, drink some matango (palm wine), and talk with them about EU policies on climate change, REDD initiatives, carbon cycling and so on. They may be formally “uneducated” and poor, but most of them have a surprisingly rational outlook on things and they show a great thirst for knowledge. Our project has given them a glimpse of another world out there, and they are very excited to be part of it.

    We now hope and wish we can develop practical routines to implement grassroots biochar projects on a larger scale, and to channel some carbon money into the farmers’ pockets. That’s our next big challenge.

  4. ingo’s avatar

    Hi all
    I am just undertaking a biochar experiment in my garden in Rkcland St. mary Norfolk UK. My Oak tree has for years sucked the goodness out of my soil leaving half my garden infertile and without light.
    I have now turned the tree into a treehouse on a stump, with a massive pile of leaves left. I have dug a 80 cm deep pit and will fire it today. The fire will be started in the bottom, then a layer of old election posters to cover the embers.
    After that I will have to pile all the leaves fast and compound them into the pit covering with more posters and fianlly a layer of earth.
    Wish me luck, I do not want to waste any of the material of the tree. best top all. Ingo

  5. Mike - make biochar yourself’s avatar

    Ingo – I understand your frustration with large trees in the garden. On my vegetable plot we really struggle with both shading and nutrient leeching because of the mature trees on three sides. On the fourth side we have and invasive patch of something (I believe it is called soomack??) which would gain about 1m per year by sending up new shoots through the lawn and beds. We have running battles with the chain saw to keep things clean and make biochar regularly.

    My advice when actually doing a burn (I appreciate it may be a little late now, but other may be reading this) is to light the material from the TOP rather than the bottom. It tends to burn much more cleanly as the smoke rises through the hottest part of the fire. Lighting at the bottom sends smoke up and away from the heat.

    Smoke itself is a pollutant and, besides making you unpopular with the neighbours.

    I do my own burns in an oil drum – top lit with plenty of ventilation around the bottom and through the middle. Once the flames die down the wood is pretty much charred through and I extinguish it with water before crushing the char and spreading it on the veggie beds.

    All the best


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  7. Chris Lang’s avatar

    Does anyone have an update on the trials in Cameroon? According to research published by Biofuelwatch recently, the trials seem to have stopped. There’s a post on REDD-Monitor by Almuth Ernsting about the research, here: Guest Post: “Slash and burn”, biochar and REDD in DR Congo and Cameroon.

    And the Biochar Fund website seems to have gone. Does anyone have a copy of the trials that this post is based on?


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