Biochar Sequestration in Soil A New Frontier Johannes

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

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

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

Bio-char Sequestration in Soil = application of incompletely combusted organic material to soil (charcoal, biomass-derived black carbon) • 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

Ubiquity of Bio-char (Biomass-Derived Black Carbon) in Soil Not an alien substance! Naturally occuring maximum concentrations 40% of soil organic matter (Forest soil from Ghana) Australia: Skjemstad et al. , 1996, Aust J Soil Res 34, 251 -271 Europe: Schmidt et al. , 1999, Eur J Soil Sci, 50, 351 -365 South Africa: Bird et al. , 1999, Global Biogeochem Cycles, 13, 923 -932 USA: Skjemstad et al. , 2002, Soil Sci Soc Am J, 66, 1249 -1255 USA: Glaser and Amelung, 2003, Global Biogeochem Cycles, 17, 1064

Chemical Stability of Bio-char - NEXAFS Bio-char (fresh) Large amounts of stable aromatic carbon structures in Bio-char (6, 700 years old) 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 NEXAFS spot spectra of particle center, black C from anthropogenic soil age 6, 700 years (Near-Edge X-ray Absorption Fine Structure) Lehmann et al. , 2005, Global Biogeochemial Cycles 19: GB 1013

Chemical Stability of Bio-char LSD 0. 05 Soils with low BC (<10%) vvvvv Soils with high BC (>60%) (pairs with identical texture and mineralogy) Liang, Lehmann et al. , unpubl. data

High Cation Exchange Capacity of Bio-char Anthropogenic Soils with >20% BC of SOC with C %B 0 1 -1 Sombroek et al. , 2003, in Lehmann et al. , Kluwer Ac Publ. Greater CEC per unit carbon in soil with high amounts of biochar

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: GB 1013

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

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% Soil Bio-char carbon 50% Soil 100 years Biomass carbon <10% Soil Bio-char carbon >30% Soil

Atmosphere 730 60 Plants 500 59 60 The Natural Carbon Cycle (in Pg) 1 Ocean 38, 000 (IPCC, 2001) 120 Soil 1500 Labile organic matter 300 Intermediate organic matter 1050 Stable organic matter Geological Reservoirs 5, 000 -10, 000 150

Atmosphere 730 Land use change The Anthropogenic Disturbance 1. 9 Land uptake 1. 9 60 Fossil fuel 120 5. 4 1. 7 Plants 500 59 60 1 Ocean 38, 000 (IPCC, 2001) Soil 1500 Labile organic matter 300 Intermediate organic matter 1050 Stable organic matter Geological Reservoirs 5, 000 -10, 000 150

Atmosphere 730 ? 1. 9 Renewable fuel -0. 2 5. 4 1. 7 -0. 2 59 Slash-and-char -0. 16 Bio-char Opportunities Agricultural Renewable Waste waste Slash-and-char fuel 0. 16 Agricultural waste Soil 1500 Ocean 38, 000 (Lehmann, Gaunt, Rondon, in review) Plants 500 0. 2 Labile organic matter 0. 02 300 Intermediate organic matter 1050 Stable organic matter Geological Reservoirs 5, 000 -10, 000 150

Atmosphere 730 Land use change Land uptake ? 1. 9 Renewable fuel -0. 2 5. 4 1. 7 -0. 2 59 Slash-and-char -0. 16 Agricultural Renewable Waste waste Slash-and-char fuel 0. 16 Agricultural waste With projected adoption of bio-fuels by 2100 (Berndes et al. , 2003) Ocean 38, 000 (Lehmann, Gaunt, Rondon, in review) Plants 500 Soil 1500 0. 2 Labile organic matter 0. 2 0. 02 9. 5 300 Intermediate organic matter 1050 Stable organic matter Geological Reservoirs 5, 000 -10, 000 150

Tradable GHG Emission Reductions kg CO 2 per ton woody biomass System change Net emissions From: Slash-and-burn 3294 To: Slash-and-char 1702 From: Wood to soil 3666 To: Bio-char energy 1903 From: Bio-fuel 3294 To: Bio-char energy 1903 (Lehmann, Gaunt, Rondon, in review) Reduction FF Subst. * Em. Reductions 1592 0 1592 1763 1147 2910 1391 1147 2538 *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: • Easy accountability (determined by application) • Low risk for C trading (high permanency) • Kyoto mechanisms applicable (tradable commodity is avoided emissions rather than sequestered C) (Lehmann, Gaunt, Rondon, in review)

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