Johannes Lehmann Department of Crop and Soil Sciences, Cornell University John Gaunt GY Associates, UK Marco Rondon TSBF-CIAT, Cali, Colombia Bio-char Sequestration in Soil A New Frontier

Sequestration of Carbon in Soil – often a finite sink! Hoosfield Barley Experiment, Rothamsted, UK (Data courtesy of Rothamsted Research, UK) Slow and finite increases of SOM

Sequestration of Carbon in Soil – often a labile sink! Upon management changes, SOM decreases rapidly again – issue of permanency (Data courtesy of Rothamsted Research, UK) Hoosfield Barley Experiment, Rothamsted, UK

Bio-char Sequestration in Soil More permanent soil carbon sink than any suggested alternatives Chemical recalcitrance not constraint by ability of the soil to provide physical protection Easily accountable Costs covered by improvement of soil fertility = application of incompletely combusted organic material to soil (charcoal, biomass-derived black carbon)

Ubiquity of Bio-char (Biomass-Derived Black Carbon) in Soil Not an alien substance! Naturally occuring maximum concentrations 40% of soil organic matter Australia: Skjemstad et al., 1996, Aust J Soil Res 34, Europe: Schmidt et al., 1999, Eur J Soil Sci, 50, South Africa: Bird et al., 1999, Global Biogeochem Cycles, 13, USA: Skjemstad et al., 2002, Soil Sci Soc Am J, 66, USA: Glaser and Amelung, 2003, Global Biogeochem Cycles, 17, 1064 (Forest soil from Ghana)

Large amounts of stable aromatic carbon structures in Bio-char Even very old particles of bio-char (black carbon) retain their high aromaticity. This is an indication of the recalcitrance of bio-char leading to high permanency in soil Lehmann et al., 2005, Global Biogeochemial Cycles 19: GB1013 Bio-char NEXAFS spot spectra of particle center, black C from anthropogenic soil age 6,700 years (Near-Edge X-ray Absorption Fine Structure) (6,700 years old) (fresh) Chemical Stability of Bio-char - NEXAFS

Chemical Stability of Bio-char vvvvvvvvv Liang, Lehmann et al., unpubl. data LSD 0.05 Soils with low BC (<10%) Soils with high BC (>60%) (pairs with identical texture and mineralogy)

High Cation Exchange Capacity of Bio-char Greater CEC per unit carbon in soil with high amounts of bio-char Sombroek et al., 2003, in Lehmann et al., Kluwer Ac Publ. Anthropogenic Soils with >20% BC of SOC with 1-10% BC

Carbon Forms on Bio-char Particles Highly aromatic in the center Oxidized near the surface 1 mm PCR and cluster analysis Lehmann et al., 2005, Global Biogeochemial Cycles 19: GB1013

(Both Unfertilized) © J. Major, 2003 High Black CLow/no Black C Application of bio-char >500 years BP! Major, DiTommaso, Lehmann, Falcão, 2005, AGEE, in review Soil Fertility of Bio-char-rich Soils Central Amazon, Brazil:

Opportunities for Bio-char Production From agricultural, forest and urban wastes Through energy production systems using bio-fuels From wastes of charcoal production Within shifting cultivation

Basic Benefit of Biomass Conversion to Bio-char Biomass carbon 100% Biomass carbon 100% Soil Bio-char carbon 50% 100 years Biomass carbon <10% Soil Bio-char carbon >30%

Atmosphere 730 Ocean 38,000 Soil 1500 Plants 500 Geological Reservoirs 5,000-10,000 Labile organic matter 300 Intermediate organic matter 1050 Stable organic matter (IPCC, 2001) The Natural Carbon Cycle (in Pg)

Atmosphere 730 Ocean 38,000 Soil 1500 Plants 500 Geological Reservoirs 5,000-10,000 Labile organic matter 300 Intermediate organic matter 1050 Stable organic matter (IPCC, 2001) 60 1 Land uptake Land use change The Anthropogenic Disturbance Fossil fuel

Atmosphere 730 Ocean 38,000 Soil 1500 Plants 500 Geological Reservoirs 5,000-10,000 Labile organic matter 300 Intermediate organic matter 1050 Stable organic matter Slash-and-char Renewable fuel Slash-and-char Renewable fuel -0.2 ? Agricultural waste 0.2 Renewable fuel 0.02 Agricultural waste 0.2 Waste (Lehmann, Gaunt, Rondon, in review) Bio-char Opportunities

Atmosphere 730 Ocean 38,000 Soil 1500 Plants 500 Geological Reservoirs 5,000-10,000 Labile organic matter 300 Intermediate organic matter 1050 Stable organic matter Slash-and-char Renewable fuel Slash-and-char Renewable fuel -0.2 ? Agricultural waste 0.2 Renewable fuel 0.02 Agricultural waste 0.2 Waste (Lehmann, Gaunt, Rondon, in review) Land uptake Land use change 9.5 With projected adoption of bio-fuels by 2100 (Berndes et al., 2003) -0.2

Tradable GHG Emission Reductions System changeNet emissionsReductionFF Subst.*Em. Reductions From: Slash-and-burn 3294 To: Slash-and-char From: Wood to soil 3666 To: Bio-char energy From: Bio-fuel 3294 To: Bio-char energy kg CO 2 per ton woody biomass (Lehmann, Gaunt, Rondon, in review) *for natural gas

Tradable GHG Emission Reductions Not considered: -Emission reductions other than CO 2 (e.g. CH 4, N 2 O) -Increased biomass production (Lehmann, Gaunt, Rondon, in review)

Tradable GHG Emission Reductions Benefits of Bio-char sequestration over any other soil C sequestration: (Lehmann, Gaunt, Rondon, in review) Easy accountability (determined by application) Low risk for C trading (high permanency) Kyoto mechanisms applicable (tradable commodity is avoided emissions rather than sequestered C)

Key Messages More permanent C sequestration than any other C sequestration method in soil More effective for increasing soil fertility than any other C sequestration method in soil More favorable to current C trading mechanisms than any other C sequestration method in soil