Agriculture Reference
In-Depth Information
these condensed vapors are used for agricultural purposes mainly in Asia and Brazil
(GERAIS, 1985; Glass, 2001; Steiner, et al., 2004b).
Japanese researchers attempt to produce charcoal with a specific pore size distribution to
favor desired microorganisms (Okimori pers. communication). Pore structure, surface area,
and adsorption properties are strongly influenced by the peak temperature during charcoal
production (Antal and Grønli, 2003). Increasing porosity is achieved with increasing
temperature but the functional groups are gradually lost. In this context, it is also important to
discern the mechanisms of nutrient retention (mainly N) due to charcoal applications. The
charcoal's low biodegradability (Kuhlbusch and Crutzen, 1995), low nutrient content
(Ogawa, 1994; Antal and Grønli, 2003), and high porosity and specific surface area (Braida,
et al., 2003) makes charcoal a rather exceptional SOM constituent.
Terra Preta
research has
shown that oxidation on the edges of the aromatic backbone and adsorption of other organic
matter to charcoal is responsible for the increased CEC, though the relative importance of
these two processes remains unclear (Liang, et al., 2006).
Energy from crop residues could lower fossil energy consumption and CO
2
-emissions,
and become a completely new income source for farmers and rural regions. The biochar by-
product of this process could serve to recycle nutrients, improve soils and sequester carbon. A
review by Johannes Lehmann (2006) and the article “
Black is the new green
” (Marris, 2006)
emphasize the potential of bio-char on a global scale. A global analysis by Lehmann, et al.
(2006) revealed that up to 12% of the total anthropogenic C emissions by land use change
(0.21 Pg C) can be off-set annually in soil, if slash and burn is replaced by slash and char.
Agricultural and forestry wastes add a conservatively estimated 0.16 Pg C yr
-1
. If the demand
for renewable fuels by the year 2100 was met through pyrolysis, bio-char sequestration could
exceed current emissions from fossil fuels (5.4 Pg C yr
-1
). The described mixture of driving
forces and technologies has the potential to use residual waste carbon-rich residues to reshape
agriculture, balance carbon and address nutrient depletion.
R
EFERENCES
Antal, M. J. and Grønli, M.
Ind. Eng. Chem. Res.
2003, 42, 1619-1640.
Bernoux, M.; Graça, P. M. A.; Cerri, C. C.; Fearnside, P. M.; Feigl, B. J. and Piccolo, M. C.
In
The biogeochemistry of the Amazon Basin
; McClain, M. E.; Victoria, R. L. and
Richey, J. E
.
; Ed.; Oxford University Press: New York, NY, 2001; pp 165-184.
Birk, J. J. 2005,
Lehrstuhl für Bodenkunde und Bodengeographie
, University of Bayreuth,
Diplomarbeit.
Braida, W. J.; Pignatello, J. J.; Lu, Y. F.; Ravikovitch, P. I.; Neimark, A. V. and Xing, B. S.
Environ. Sci. Technol
. 2003, 37, 409-417.
Day, D.;Evans, R. J.;Lee, J. W. and Reicosky, D.
Energy.
2005, 30, 2558-2579.
Fearnside, P. M.
Climatic Change
. 1997, 35, 321-360.
Fearnside, P. M.
Climatic Change.
2000, 46, 115-158.
Fearnside, P. M.; Lima, P. M.; Graça, A. and Rodrigues, F. J. A.
Forest Ecol. Management.
2001, 146, 115-128.
Gehring, C. 2003, University of Bonn,
PhD theses.
GERAIS, F. C. T. D. M. STI/CIT, Brasilia,
Documentos
23, 1985, pp 18.
