A revolutionary method of carbon sequestration, relatively cheap and with huge environmental and agricultural benefits, has been discovered already more then 20 years ago. Wood chips from tree branches as soil amendment and as permanent soil cover.  It can sequester almost 10 tons of CO2 per ha per year (1). And it is applicable to millions of hectares of cropland mostly in the subtropical and moderate climate regions. But nobody seems to bother. Why?

Maybe the name was wrongly chosen.. Ramial Chipped Wood (RCW). In French, Bois Raméal Fragmenté (BRF). Originally it was a Canadian invention, by Gilles Lémieux, a forest scientist, who is at this very moment very sick and might not recover. He spent more than 20 years of research on the formation of humus, and the important role of woody material in this. His credo: the soil is a biosphere, and the best thing for agriculture is to imitate the natural forest conditions. Hopefully he will still see in his life the popularisation of his work (2).

In France, a network of more then 300 enthousiasts, informing eachother regularly on the Yahoo BRF forum (3), mainly use the chips in their gardens, with kind donations of professional gardeners who donot know what to do with their shredded garden waste. There are a few experimental farms (4), who are by no exception very happy with the method. Mostly because of the reduced need of irrigation and the abolishment of ploughing work. But in general it is a BIG psychological step for farmers to give up ploughing and to have the soil permamently covered. There is a very large and growing group of farmers that practice the socalled “Conservation Agriculture” (CA), or No-till agriculture, or in French Semis Direct (Direct seeding, without ploughing). Basically this type of agriculture will leave all the crop residues on the land after harvesting, and will in the next season seed directly into shallow furrows. This method has also prooved to efficiently raise the carbon content of the soil, and can sequester 1 to 2 tons of CO2e per ha per year. In the USA the largest voluntary carbon offset agency “Chicago Climate Exchange” acknowledged this and since then a few million of ha’s of cropland has been certified as carbon sink. It is not big money, but because average landownership is pretty big in the USA, the few hundred bugs per year was sufficient for many farmers to convert themselves to CA! (5)  With Ramial Chipped Wood, this could be a few thousand bugs per year, but until now, no single large cropfarmer in the USA knows about it. The reason for the spectacular humus growth with RCW is the high content of carbon in the form of semi-polymerised lignine in the shredded tree branches of which 30-40% turns into stable humus, contrary to the carbon in crop residues or compost of which only 3-5% is left after a few years (6).

Science and international agricultural institutions like the FAO  (7) acknowledged already firmly the role of soils in climate change. In fact soils are globally the most important stock of CO2. Deep ploughing of cropland, desertification and erosion are the most important factors for declining this stock. But the problem according to them is the accurate measurement of soil carbon. Soil carbon contents can fluctuate quite considerably in time and space, and makes therefor any claim on changes of soil organic matter (SOL) questionable. Moreover measurement techniques differ per country and are quite expensive, making international research and policies difficult (8).  Soil carbon sequestration will therefor for example not be part of implementation of the Kyoto protocol.

Probably this is the reason why RCW is still under the radar of environmentalists, policymakers and farmers. The large scale introduction of RCW depends on carbon offset payments. To install the system, approximately 1000 euro per ha is needed to plant hedgerows and to apply the first amendment of chips to the soil, according to a “carbon farming network” in Bulgaria who wants to start a campaign for farmers to help them in adapting to the climate change (9). Compared to sequestering CO2 in old mines this is still more than two times cheaper (20 euro per ton CO2e, instead of more then 50 euro per ton), not included all environmental benefits. But just because we can not precisely measure it contrary to the amount of CO2 that runs through a pipeline into geological layers, we delay the implementation of this very promising technology.

Unfortunately too often scientific research only concludes with saying that more scientific reearch is needed. In this case, especially given the urgent question of how agriculture could contribute to climate change mitigation AND how it should adapt to climate change, we need more than that. Why not setting up a number of model RCW farms in each climate region and on each soil type, and use their data as reference for a robust offset scheme with a comfortable fault margin? Even if we only declare 50% of the actual amount of CO2 sequestered by the RCW method it would still be sufficient for the farmer to pay for the initial investments needed!

1. www.ctastree.be
2. www.hydrogeochem.qc.ca
3. fr.groups.yahoo.com/group/brf4
4. http://fermedupouzat.free.fr/pages/brf/formation.htm
5. http://www.agragate.com
6. www.sbf.ulaval.ca/brf/regenerating_soils_98.html
7. www.fao.org/AG/AGL/agll/carbonsequestration
8.http://ec.europa.eu/environment/soil/pdf/climsoil_report_dec_2008.pdf
9. www.greenbeltburgas.weebly.com

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