Greenhouse gas emissions decrease with charcoal additions to soils

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Greenhouse gas emissions decrease with charcoal
additions to soils

• Marco A. Rondón, Juan A. Ramirez
• TSBF Institute, CIAT
• Johannes Lehmann, Cornell University
• USDA Symposium on C sequestration.
  Baltimore, March 24, 2005

Centro Internacional de Agricultura Tropical
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Charcoal has been part of human history
It can be of natural or anthropogenic origin.
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Charcoal results from incomplete burning of
biomass
Up to 40 of non combusted biomass remain in
the sites 3 -8 ton/ha of charcoal added to soils
after a burning cycle in the Amazon
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Rondon et al, 2002
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Methods for charcoal production were developed
long time ago.
And remain unchanged..
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Simple methods have also been developed to
improve efficiency and reduce health risk
41 Mton charcoal/y produced worldwide 50 in
Africa, 35 in Latinamerica
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Charcoal is commonly used in home gardens, raised
vegetable plots and plant nurseries
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Charcoal additions to soil enhance crop
performance
Lehmann and Rondon, 2004
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Black carbon adsorbs nitrogen and reduces N
availability
Glaser, 1999
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Lack of Information on the effects of charcoal on
fluxes of GHG.

• Objective
• Study the effect of charcoal additions to low
  fertility soils on net fluxes of CH4 and N2O
  from a legume and a tropical grass

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Experimental details Two plant types Legume
(Glycine max, cultivar. ICA 6) Gramminea
(Brachiaria humidicola, CIAT 679) Soil Typic
haplustox (ph 4.5) very low in nutrients (2 kg
pot-1) Four levels of charcoal 0, 7.5, 15 and
30 g bio-char. kg soil-1 Charcoal from
Calliandra callothirsus . Ground at lt1mm and
mixed with soil prior to sowing Three
replicates in a CRBD
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Plants grow for 63days in a glasshouse Pots at
50-60 WFPS Root aerial biomass recovered Soil
analysis
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GHG exchange measured weekly Closed vented
chamber approach
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Simultaneous analysis of CH4, N2O and CO2 by GC.
FID, ECD detectors
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Results
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Charcoal improve soil quality
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Black Carbon Effect on BNF
BNF of common beans (Phaseolus vulgaris L.)
determined by isotope dilution (N4)
Rondon et al., in prep.
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20 year time horizon
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Similar results have been found for corn and
tropical grasses in savanna oxisols
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And in Andisols used for vegetable production in
high fertility trenches on steep hillsides.
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CONCLUSIONS

• Effect of charcoal on plant yields can be higher
  in legumes due to their BNF ability
• Net fluxes of methane and nitrous oxide decrease
  with additions of charcoal to soils
• Even small amounts of charcoal added to soils can
  offset net emissions of CH4 and N2O
• The overall GWP of a cropping system can be
  controlled by varying the amounts of charcoal
  added to soils

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Opportunities to benefit form charcoal in small
scale agriculture in the tropics
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Fast growing trees and shrubs will sustain
production of charcoal
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A bright future for black Carbon
THANK YOU!