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Agroforestry as a strategy for carbon sequestration
P. K. Ramachandran Nair,
B. Mohan Kumar,
Vimala D. Nair,
P. K. Ramachandran Nair
Center for Subtropical Agroforestry, School of Forest Resources and Conservation, University of Florida, Gainesville, Florida 32611-0410, USA
Search for more papers by this authorB. Mohan Kumar
Center for Subtropical Agroforestry, School of Forest Resources and Conservation, University of Florida, Gainesville, Florida 32611-0410, USA
Department of Silviculture and Agroforestry, Kerala Agricultural University, Thrissur 680656, Kerala, India
Search for more papers by this authorVimala D. Nair
Soil and Water Science Department, University of Florida, Gainesville, Florida 32611-0550, USA
Search for more papers by this authorP. K. Ramachandran Nair,
B. Mohan Kumar,
Vimala D. Nair,
P. K. Ramachandran Nair
Center for Subtropical Agroforestry, School of Forest Resources and Conservation, University of Florida, Gainesville, Florida 32611-0410, USA
Search for more papers by this authorB. Mohan Kumar
Center for Subtropical Agroforestry, School of Forest Resources and Conservation, University of Florida, Gainesville, Florida 32611-0410, USA
Department of Silviculture and Agroforestry, Kerala Agricultural University, Thrissur 680656, Kerala, India
Search for more papers by this authorVimala D. Nair
Soil and Water Science Department, University of Florida, Gainesville, Florida 32611-0550, USA
Search for more papers by this authorAbstract
During the past three decades, agroforestry has become recognized the world over as an integrated approach to sustainable land use because of its production and environmental benefits. Its recent recognition as a greenhouse gas–mitigation strategy under the Kyoto Protocol has earned it added attention as a strategy for biological carbon (C) sequestration. The perceived potential is based on the premise that the greater efficiency of integrated systems in resource (nutrients, light, and water) capture and utilization than single-species systems will result in greater net C sequestration. Available estimates of C-sequestration potential of agroforestry systems are derived by combining information on the aboveground, time-averaged C stocks and the soil C values; but they are generally not rigorous. Methodological difficulties in estimating C stock of biomass and the extent of soil C storage under varying conditions are compounded by the lack of reliable estimates of area under agroforestry. We estimate that the area currently under agroforestry worldwide is 1,023 million ha. Additionally, substantial extent of areas of unproductive crop, grass, and forest lands as well as degraded lands could be brought under agroforestry. The extent of C sequestered in any agroforestry system will depend on a number of site-specific biological, climatic, soil, and management factors. Furthermore, the profitability of C-sequestration projects will depend on the price of C in the international market, additional income from the sale of products such as timber, and the cost related to C monitoring. Our knowledge on these issues is unfortunately rudimentary. Until such difficulties are surmounted, the low-cost environmental benefit of agroforestry will continue to be underappreciated and underexploited.
References
- Ågren, G. I., Bosatta, E., Balesdent, J. (1996): Isotope discrimination during decomposition of organic matter: A theoretical analysis. Soil Sci. Soc. Am. J. 60, 1121–1126.
- Akinnifesi, F. K., Rowe, E. C., Livesley, S. J., Kwesiga, F. R., Vanlauwe, B., Alegre, J. C. (2004): Tree root architecture, in van Noordwijk, M., Cadisch, G., Ong, C. K. (eds.): Below-Ground Interactions in Tropical Agroecosystems: Concepts and Models with Multiple Plant Components. CABI Publishing, Wallingford, UK, pp. 61–81.
- Albrecht, A., Kandji, S. T. (2003): Carbon sequestration in tropical agroforestry systems. Agric. Ecosyst. Environ. 99, 15–27.
- Albrecht, G. C., Blanchart, E., Sitompul, S. M., Vanlauwe, B. (2004): Below-ground input: relationships with soil quality, soil C storage, in van Noordwijk, M., Cadisch, G., Ong, C. K.: Below-Ground Interactions in Tropical Agroecosystems: Concepts and Models with Multiple Plant Components. CABI Publishing, Wallingford, UK, pp. 17.
-
Amézquita, M. C.,
Ibrahim, M.,
Llanderal, T.,
Buurman, P.,
Amézquita, E.
(2005):
Carbon sequestration in pastures, silvopastoral systems and forests in four regions of the Latin American tropics.
J. Sust. For.
21,
31–49.
10.1300/J091v21n01_02 Google Scholar
- Antle, J. M., Stoorvogel, J. J., Valdivia, R. O. (2007): Assessing the economic impacts of agricultural carbon sequestration: Terraces and agroforestry in the Peruvian Andes. Agric. Ecosyst. Environ. 122, 435–445.
- Arroja, L., Dias, A. C., Capela, I. (2006): The role of Eucalyptus globulus forest and products in carbon sequestration. Climatic Change 74, 123–140.
- Bachmann, J., Guggenberger, G., Baumgartl, Th., Ellenbrock, R. H., Urbanek, E., Goebel, M.-O., Kaiser, K., Horn, R., Fischer, W. R. (2008): Physical carbon-sequestration mechanisms under special considerations of soil wettability. J. Plant Nutr. Soil Sci. 171, 14–26.
-
Baker, T. R.,
Phillips, O. L.,
Malhi, Y.,
Almeida, S.,
Arroyo, L.,
Di Fiore, A.,
Erwin, T.,
Killeen, T. J.,
Laurance, S. G.,
Laurance, W. F.,
Lewis, S. L.,
Lloyd, J.,
Monteagudo, A.,
Neill, D. A.,
Patino, S.,
Pitman, N. C. A.,
Silva, J. N. M.,
Vasquez Martinez, R.
(2004):
Variation in wood density determines spatial patterns in Amazonian forest biomass.
Global Change Biol.
10,
1–18.
10.1111/j.1365-2486.2004.00751.x Google Scholar
- Ball, J. B., Wormald, T. J., Russo, L. (1995): Experience with mixed and single species plantations. Commonwealth For. Rev. 74, 301–305.
- Balvanera, P., Kremen, C., Martinez-Ramos, M. (2005): Applying community structure analysis to ecosystem function: examples from pollination and carbon storage. Ecol. Appl. 15, 360–375.
- Batjes, N. H. (1996): The total carbon and nitrogen in soils of the world. Eur. J. Soil Sci. 47, 151–163.
- Bauhus, J., van Winden, A. P., Nicotra, A. B. (2004): Above-ground interactions and productivity in mixed-species plantations of Acacia mearnsii and Eucalyptus globulus. Can. J. For. Res. 34, 686–694.
- Beer, J., Bonnemann, A., Chavez, W., Fassbender, H. W., Imbach, A. C., Martel, I. (1990): Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) or poro (Erythrina poeppigiana) in Costa Rica. V. Productivity indices, organic material models and sustainability over ten years. Agroforest. Syst. 12, 229–249.
- Boffa, J. M. (1999): Agroforestry parklands in sub-Saharan Africa. FAO Conservation Guide 34, FAO, Rome, p. 230.
- Brown, S. (2002): Measuring carbon in forests: current status and future challenges. Environ. Pollut. 116, 363–372.
- Brown, L. R. (2004): Outgrowing the earth: The food security challenge in an age of falling water tables and rising temperatures. W.W. Norton, New York, p. 239.
- Bunker, D. E., DeClerk, F., Bradford, J. C., Colwell, R. K., Perfecto, Y., Phillips, O. L., Sankaran, M., Naeem, S. (2005): Species loss and above-ground carbon storage in a tropical forest. Science 310, 1029–1031.
- Cairns, M. A., Brown, S., Helmer, E. H., Baumgardner, G. A. (1997): Root biomass allocation in the world's upland forests. Oecologia 111, 1–11.
- Carter, M. R. (1996): Analysis of soil organic matter in agroecosystems, in Carter, M. R., Stewart, B. A.: Structure and organic matter storage in agricultural soil. CRC Press, Boca Raton, FL, USA, pp. 3–11.
- Clarke, W. C., Thaman, R. R. (eds.) (1993): Agroforestry in the pacific islands. UN University, Tokyo, p. 297.
- Connin, S. L., Virginia, R. A., Chamberlain, C. P. (1997): Carbon isotopes reveal soil organic matter dynamics following arid land shrub expansion. Oecologia 110, 374–386.
- de Jong, B. H. J. (2001): Uncertainties in estimating the potential for carbon mitigation of forest management. For. Ecol. Manage. 154, 85–104.
- Dixon, R. K. (1995): Agroforestry system: sources or sinks of greenhouse gases? Agroforest. Syst. 31, 99–116.
- Dossa, E. L., Fernandes, E. C. M., Reid, W. S., Ezui, K. (2008): Above- and belowground biomass, nutrient and carbon stocks contrasting an open-grown and a shaded coffee plantation. Agroforest. Syst. 72, 103–115.
- Duguma, B., Gockowski, J., Bakala, J. (2001): Smallholder cacao (Theobroma cacao Linn.) cultivation in agroforestry systems of West and Central Africa: challenges and opportunities. Agroforest. Syst. 51, 177–188.
- Elias, M., Potvin, C. (2003): Assessing inter- and intra-specific variation in trunk carbon concentration for 32 neotropical tree species. Can. J. Forest Res. 33, 1039–1045.
- Elliott, E. T., Coleman, D. C. (1988): Let the soil work for us. Ecol. Bull. 39, 23–32.
- FAO (2004): Assessing carbon stocks and modelling win–win scenarios of carbon sequestration through land-use changes. Food and Agriculture Organization of the United Nations, Rome, p. 156.
- FAO (2007): State of the World's Forests 2007. www.fao.org (accessed: Jan. 20, 2008).
- Feller, C., Beare, M. H. (1997): Physical control of soil organic matter dynamics in the tropics. Geoderma 79, 69–116.
- Flessa, H., Amelung, W., Helfrich, M., Wiesenberg, G. L. B., Gleixner, G., Brodowski, S., Rethemeyer, J., Kramer, C., Grootes, P. M. (2008): Storage and stability of organic matter and fossil carbon in a Luvisol and Phaeozem with continuous maize cropping: A synthesis. J. Plant Nutr. Soil Sci. 171, 36–51.
- Forrester, D. I., Bauhus, J., Cowie, A. L. (2006): Carbon allocation in a mixed-species plantation of Eucalyptus globulusand Acacia mearnsii. For. Ecol. Manage. 233, 275–284.
- Garrett, H. E., Rietveld, W. J., Fisher, R. F. (eds.) (2000): North American agroforestry: An integrated science and practice. American Society of Agronomy, Madison, WI, USA, p. 402.
- Gruenewald, H., Brandt, B. K. V., Schneider, B. U., Bens, O., Kendzia, G., Hüttl, R. F. (2007): Agroforestry systems for the production of woody biomass for energy transformation purposes. Ecol. Eng. 29, 319–328.
- Haile, S. G. (2007): Soil carbon sequestration and stabilization in tree-based pasture systems in Florida. PhD thesis, University of Florida, Gainesville, FL, USA, p. 130.
- Haile, S. G., Nair, P. K. R., Nair, V. D. (2008): Carbon storage of different soil-size fractions in Florida silvopastoral systems. J. Environ. Qual. 37, 1789–1797.
- Hassink, J. (1997): The capacity of soils to physically protect organic C and N. Plant Soil 191, 77–87.
-
Hüttl, R. F.,
Bens, O.,
Schneider, U. (eds.)
(2000):
Forests and Energy: 1st Hannover EXPO2000 World Forest Forum.
Ecol. Eng.
16,
135–135.
10.1016/S0925-8574(00)00160-9 Google Scholar
- IPCC (2000): Land use, Land-use Change, and Forestry. A Special Report of the IPCC. Cambridge University Press Cambridge, UK, p. 375.
- IPCC (2007): Climate Change 2007: Mitigation of Climate Change. Working Group III contribution to the Intergovernmental Panel on Climate Change, Fourth Assessment Report. Bangkok, Thailand. http://www.ipcc.ch/ipccreports/index.htm (accessed: Jan. 28, 2008).
- Jackson, N. A., Wallace, J. S., Ong, C. K. (2000): Tree pruning as a means of controlling water use in an agroforestry system in Kenya. For. Ecol. Manage. 126, 133–148.
- Jactel, H., Brockerhoff, E., Duelli, P. (2005): A test of the biodiversity–stability theory: meta-analysis of tree species diversity effects on insect pest infestations, and re-examination of responsible factors, in Scherer-Lorenzen, M., Körner, C., Schulze, E.-D. (eds.): Forest Diversity and Function: Temperate and Boreal Systems. Ecological Studies, 176, Springer, Berlin, pp. 235–262.
- Jenkinson, D. S. (1990): The turnover of organic carbon and nitrogen in soil. Phil. Trans. R. Soc. London 329B, 361–368.
- Jepsen, M. R. (2006): Above-ground carbon stocks in tropical fallows, Sarawak, Malaysia. For. Ecol. Manage. 225, 287–295.
- Jiménez, J. J., Lal, R., Leblanc, H. A., Russo, R. O. (2007): Soil organic carbon pool under native tree plantations in the Caribbean lowlands of Costa Rica. For. Ecol. Manage. 241, 134–144.
- Jobbágy, E. G., Jackson, R. B. (2000): The vertical distribution of soil organic carbon and its relation to climate and vegetation. Ecol. Appl. 10, 423–436.
- Kaur, B., Gupta, S. R., Singh, G. (2002): Carbon storage and nitrogen cycling in silvopastoral systems on a sodic soil in northwestern India. Agroforest. Syst. 54, 21–29.
- Keenan, R., Lamb, D., Sexton, G. (1995): Experience with mixed species rainforest plantations in North Queensland. Commonwealth For. Rev. 74, 315–321.
- Kirby, K. R., Potvin, C. (2007): Variation in carbon storage among tree species: Implications for the management of a small-scale carbon sink project. For. Ecol. Manage. 246, 208–221.
- Kögel-Knabner, I., Ekschmitt, K., Flessa, H., Guggenberger, G., Matzner, E., Marschner, B., von Lützow, M. (2008): An integrative approach of organic matter stabilization in temperate soils: Linking chemistry, physics, and biology. J. Plant Nutr. Soil Sci. 171, 5–13.
- Kumar, B. M. (2006): Carbon sequestration potential of tropical homegardens, in Kumar, B. M., Nair, P. K. R. (eds.): Tropical Homegardens: A Time-Tested Example of Sustainable Agroforestry. Advances in Agroforestry 3, Springer, Dordrecht, the Netherlands, pp. 185–204.
- Kumar, B. M., Long, J. N., Kumar, P. (1995): A density management diagram for teak plantations of Kerala in peninsular India. For. Ecol. Manage. 74, 125–132.
- Kumar, B. M., George, S. J., Jamaludheen, V., Suresh, T. K. (1998a): Comparison of biomass production, tree allometry and nutrient use efficiency of multipurpose trees grown in wood lot and silvopastoral experiments in Kerala, India. For. Ecol. Manage. 112, 145–163.
- Kumar, B. M., Kumar, S. S., Fisher, R. F. (1998b): Intercropping teak with Leucaena increases tree growth and modifies soil characteristics. Agroforest. Syst. 42, 81–89.
- Ladd, J. N., Amato, M., Oades, J. M. (1985): Decomposition of plant material in Australian soils. III. Residual organic and microbial biomass carbon and nitrogen from isotope–labeled legume material and soil organic matter, decomposing under field conditions. Aust. J. Soil Res. 23, 603–611.
- Lal, R. (2001): Potential of desertification control to sequester carbon and mitigate the greenhouse effect. Clim. Change 51, 35–72.
- Lal, R. (2004): Soil carbon sequestration impacts on global climate change and food security. Science 304, 1623–1627.
- Lal, R. (2005): Forest soils and carbon sequestration. For. Ecol. Manage. 220, 242–258.
- Lal, R. (2007): Soil carbon stocks under present and future climate with specific reference to European ecoregions. Nutr. Cycl. Agroecosyst. 81, 113–127 DOI: 10.1007/s10705-007-9147-x
- Makumba, W., Akinnifesi, F. K., Janssen, B., Oenema, O. (2007): Long-term impact of a gliricidia-maize intercropping system on carbon sequestration in southern Malawi. Agric. Ecosyst. Environ. 118, 237–243.
-
Makundi, W. R.,
Sathaye, J. A.
(2004):
GHG mitigation potential and cost in tropical forestry – relative role for agroforestry.
Environ. Dev. Sustain.
6,
235–260.
10.1023/B:ENVI.0000003639.47214.8c Google Scholar
- Malhi, Y., Roberts, J. T., Betts, R. A., Killeen, T. J., Li, W., Nobre, C. A. (2008): Climate change, deforestation, and the fate of the Amazon. Science 319, 169–172.
- Marschner, B., Brodowski, S., Dreves, A., Gleixner, G., Gude, A., Grootes, P. M., Hamer, U., Heim, A., Jandl, G., Ji, R., Kaiser, K., Kalbitz, K., Kramer, C., Leinweber, P., Rethemeyer, J., Schäffer, A., Schmidt, M. W. I., Schwark, L., Wiesenberg, G. L. B. (2008): How relevant is recalcitrance for the stabilization of organic matter in soils? J. Plant Nutr. Soil Sci. 171, 91–110.
- Martens, D. A. (2000): Plant residue biochemistry regulates soil carbon cycling and carbon sequestration. Soil Biol. Biochem. 32, 361–369.
- Montagnini, F., Nair, P. K. R. (2004): Carbon sequestration: An underexploited environmental benefit of agroforestry systems. Agroforest. Syst. 61, 281–295.
-
Montagnini, F.,
Cusack, D.,
Petit, B.,
Kanninen, M.
(2005):
Environmental services of native tree plantations and agroforestry systems in Central America.
J. Sust. For.
21,
51–67.
10.1300/J091v21n01_03 Google Scholar
- Mutuo, P. K., Cadisch, G., Albrecht, A., Palm, C. A., Verchot, L. (2005): Potential of agroforestry for carbon sequestration and mitigation of green house gas emissions from soils in the tropics. Nutr. Cycl. Agroecosyst. 71, 43–54.
- Nair, P. K. R. (ed.) (1989): Agroforestry Systems in the Tropics. Kluwer, Dordrecht, the Netherlands, p. 664.
- Nair, P. K. R. (2007): The coming of age of agroforestry. J. Sci. Food Agri. 87, 1613–1619.
- Nair, P. K. R., Nair, V. D. (2003): Carbon storage in North American agroforestry systems, in Kimble, J., Heath, L.S., Birdsey, R. A., Lal, R. (eds.): The Potential of U.S. Forest Soils to Sequester Carbon and Mitigate the Greenhouse Effect. CRC Press, Boca Raton, FL, USA, pp. 333–346.
- Nair, P. K. R., Buresh, R. J., Mugendi, D. N., Latt, C. R. (1999): Nutrient cycling in tropical agroforestry systems: Myths and science, in Buck, L. E., Lassoie, J. P., Fernandes, E. C. M.: Agroforestry in Sustainable Agricultural Systems. CRC Press, Boca Raton, FL, USA, pp. 1–31.
- Nair, P. K. R., Gordon, A. M., Mosquera-Losada, M.-R. (2008): Agroforestry, in Jorgensen, S. E., Fath, B. D. (eds): Ecological Engineering. Encyclopedia of Ecology, Vol. 1, Elsevier, Oxford, U.K., pp. 101–110.
- Nelson, K. C., de Jong, B. H. J. (2003): Making global initiatives local realities: Carbon mitigation projects in Chiapas, Mexico. Global Env. Change 13, 19–30.
- Oelbermann, M., Voroney, R. P. (2007): Carbon and nitrogen in a temperate agroforestry system: Using stable isotopes as a tool to understand soil dynamics. Ecol. Eng. 29, 342–349.
- Oelbermann, M., Voroney, R. P., Kass, D. C. L., Schlönvoigt, A. M. (2005): Above- and belowground inputs in 19, 10, and 4-year old Costa Rican alley cropping systems. Agric. Ecosyst. Environ. 105, 163–172.
- Oelbermann, M., Voroney, R. P., Gordon, A. M., Kass, D. C. L., Schlönvoigt, A. M., Thevathasan, N. V. (2006): Carbon input, soil carbon pools, turnover and residue stabilization efficiency in tropical and temperate agroforestry systems. Agroforest. Syst. 68, 27–36.
- Ojima, D. S., Kittel, T. G. F., Rosswall, T., Walker, B. H. (1999): Critical issues for understanding global change effects on terrestrial ecosystems. Ecol. Applic. 1, 316–325.
- Oren, R., Ellsworth, D. S., Johnsen, K. H., Phillips, N., Ewers, B., Maler, C., Schaefer, K. V. R., McCarthy, H., Hendrey, H., McNutty, S. G., Katul, G. G. (2001): Soil fertility limits carbon sequestration by forest ecosystems in a CO2-enriched atmosphere. Nature 411, 469–471.
-
Palm, C. A.,
Tomich, T.,
van Noordwijk, M.,
Vosti, S.,
Alegre, J.,
Gockowski, J.,
Verchot, L.
(2004):
Mitigating GHG emissions in the humid tropics: Case studies from the Alternatives to Slash-and-Burn Program (ASB).
Environ. Dev. Sust.
6,
145–162.
10.1023/B:ENVI.0000003634.50442.ca Google Scholar
- Parrotta, J. A. (1999): Productivity, nutrient cycling and succession in single- and mixed-species stands of Casuarina equisetifolia, Eucalyptus robusta and Leucaena leucocephala in Puerto Rico. For. Ecol. Manage. 124, 45–77.
- Parton, W. J., Schimel, D. S., Cole, C. V., Ojima, D. S. (1987): Analysis of factors controlling soil organic matter levels in Great Plains grasslands. Soil Sci. Soc. Am. J. 51, 1173–1179.
- Peichl, M., Thevathasan, N. V., Gordon, A. M., Huss, J., Abohassan, R. A. (2006): Carbon sequestration potentials in temperate tree-based intercropping systems, southern Ontario, Canada. Agroforest. Syst. 66, 243–257.
- Redondo-Brenes, A., Montagnini, F. (2006): Growth, productivity, aboveground biomass, and carbon sequestration of pure and mixed native tree plantations in the Caribbean lowlands of Costa Rica. For. Ecol. Manage. 232, 168–178.
- Reisner, Y., de Filippi, R., Herzog, F., Palma, J. (2007): Target regions for silvoarable agroforestry in Europe. Ecol. Eng. 29, 401–418.
- Rigueiro-Rodríguez, A., McAdam, J. H., Mosquera-Losada, M. R. (eds). (2008): Agroforestry in Europe. Advances in Agroforestry 5. Springer, Dordrecht, the Netherlands (in press).
- Roshetko, M., Delaney, M., Hairiah, K., Purnomosidhi, P. (2002): Carbon stocks in Indonesian homegarden systems: Can smallholder systems be targeted for increased carbon storage? Am. J. Alt. Agr. 17, 125–137.
- Russell, A. E., Cambardella, C. A., Ewel, J. J., Parkin, T. B. (2004): Species, rotation, and life-form diversity effects on soil carbon in experimental tropical ecosystems. Ecol. Appl. 14, 47–60.
- Sanchez, P. A. (2000): Linking climate change research with food security and poverty reduction in the tropics. Agric. Ecosyst. Environ. 82, 371–383.
- Sarkhot, D. V., Comerford, N. B., Jokela, E. J., Reeves III, J. B., Harris, W. G. (2007): Aggregation and aggregate carbon in a forested southeastern coastal plain spodosol. Soil Sci. Soc. Am. J. 71, 1779–1787.
- Schimel, D. S., Braswell, B. H., Holland, E. A., McKeown, R., Ojima, D. S., Painter, T. H., Parton, W. J., Townsend, A. R. (1994): Climatic, edaphic, and biotic controls over storage and turnover of carbon in soils. Global Biogeochem. Cycl. 8, 279.
- Schlamadinger, B., Marland, G. (1996): The role of forest and bioenergy strategies in the global carbon cycle. Biomass Bioenergy 10, 275–300.
- Schlesinger, W. H., Lichter, J. (2001): Limited carbon storage in soil and litter of experimental forest plots under increased atmospheric CO2. Nature 411, 466–468.
- Schlesinger, W. H., Reynolds, J. E., Cunningham, G. L., Huenneke, L. F., Jarrell, W. M., Virginia, R. A., Whitford, W. G. (1990): Biological feedbacks in global desertification. Science 247, 1043–1048.
- Schroth, G., D'Angelo, S. A., Teixeira, W. G., Haag, D., Lieberei, R. (2002): Conversion of secondary forest into agroforestry and monoculture plantations in Amazonia: consequences for biomass, litter and soil carbon stocks after 7 years. For. Ecol. Manage. 163, 131–150.
- Schroth, G., Schaller, M., Jiménez, F. (2007): Below-ground interactions in tree-crop agroforestry: Need for a new approach, in Batish, D. R., Kohli, R. K., Jose, S., Singh, H. P. (eds.): Ecological Basis of Agroforestry. CRC Press, Boca Raton, FL, USA, pp. 159–170.
- Sharrow, S. H., Ismail, S. (2004): Carbon and nitrogen storage in agroforests, tree plantations, and pastures in western Oregon, USA. Agroforest. Syst. 60, 123–130.
- Shepherd, D., Montagnini, F. (2001): Carbon sequestration potential in mixed and pure tree plantations in the humid tropics. J. Trop. For. Sci. 13, 450–459.
- Six, J., Elliott, E. T., Paustian, K. (2000): Soil macroaggregate turnover and microaggregate formation: a mechanism for C sequestration under no–tillage agriculture. Soil Biol. Biochem. 32, 2099–2103.
- Soil Science Society of America (2001): Carbon Sequestration: Position of the Soil Science Society of America (SSSA). SSSA, Madison, WI, available at www.soils.org/pdf/pos_paper_carb_seq.pdf (accessed: Jan. 20, 2008).
- Sorensen, L. H. (1972): Stabilization of newly formed amino acid metabolites in soil by clay minerals. Soil Sci. Soc. Am. J. 114, 5–11.
- Strand, A. E., Pritchard, S. G., McCormack, M. L., Davis, M. A., Oren, R. (2008): Irreconcilable differences: fine-root life spans and soil carbon persistence. Science 319, 456–458.
- Swamy, S. L., Puri, S. (2005): Biomass production and C-sequestration of Gmelina arborea in plantation and agroforestry system in India. Agroforest. Syst. 64, 181–195.
- Takimoto, A., Nair, P. K. R., Alavalapati, J. R. R. (2008a): Socioeconomic potential of carbon sequestration through agroforestry in the West African Sahel. Mit. Adapt. Strat. Global Change. 13, 745–761, DOI: 10.1007/s11027-007-9140-3
- Takimoto, A., Nair, P. K. R., Nair, V. D. (2008b): Carbon stock and sequestration potential of traditional and improved agroforestry systems in the West African Sahel. Agri. Eco. Environ. 125, 159–166.
- Tejwani, K. G. (1994): Agroforestry in India. Oxford and IBH, New Delhi, p. 233.
- Torn, M. S., Vitousek, P. M., Trumbore, S. E. (2005): The influence of nutrient availability on soil organic matter turnover estimated by incubations and radiocarbon modeling. Ecosystems 8, 352–372.
- van Noordwijk, M., Hairiah, K., Woomer, P. L., Murdiyarso, D. (1998): Criteria and indicators of forest soils used for slash–and–burn agriculture and alternative land uses in Indonesia, in Davidson E. (ed.): The Contribution of Soil Science to the Development and Implementation of Criteria and Indicators of Sustainable Forest Management. ASA Special Publication, Am. Soc. Agron., Madison, WI, USA, pp. 137–153.
- van Noordwijk, M., Rahayu, S., Williams, S. E., Hairiah, K., Khasanah, N., Schroth, G. (2004): Crop and tree root-system dynamics, in van Noordwijk, M., Cadisch, G., Ong, C. K. (eds.): Below-Ground Interactions in Tropical Agroecosystems: Concepts and Models with Multiple Plant Components. CABI Publishing, Wallingford, UK, pp. 83–107.
- Vanlauwe, B., Nwoke, O. C., Sanginga, N., Merckx, R. (1996): Impact of the residue quality on the carbon and nitrogen mineralization of leaf and root residues of three agroforestry species. Plant Soil 183, 221–231.
- Viswanath, S., Nair, P. K. R., Kaushik, P. K., Praksasam, U. (2000): Acacia nilotica trees in rice fields: a traditional agroforestry system in central India. Agroforest. Syst. 50, 157–177.
- Volk, T. A., Verwijst, T., Tharakan, P. J., Abrahamson, L. P., White, E. H. (2004): Are short-rotation woody crops sustainable? Proc. 2nd World Conference on Biomass for Energy, Industry and Climate Protection, May 10–14, 2004, FAO, Rome, Italy, pp. 34–39.
- von Lützow, M., Kögel-Knabner, I., Ekschmitt, K., Matzner, E., Guggenberger, G., Marschner, B., Flessa, H. (2006): Stabilization of organic matter in temperate soils: mechanisms and their relevance under different soil conditions – a review. Eur. J. Soil Sci. 57, 426–445.
- von Lützow, M., Kögel-Knabner, I., Ekschmitt, K., Flessa, H., Guggenberger, G., Matzner, E., Marschner, B. (2007): SOM fractionation methods: Relevance to functional pools and to stabilization mechanisms. Soil Biol. Biochem. 39, 2183–2207.
- von Lützow, M., Kögel-Knabner, I., Ludwig, B., Matzner, E., Flessa, H., Ekschmitt, K., Guggenberger, G., Marschner, B., Kalbitz, K. (2008): Stabilization mechanisms of organic matter in four temperate soils: Development and application of a conceptual model. J. Plant Nutr. Soil Sci. 171, 111–124.
- Watson, R. T., Noble, I. R., Bolin, B., Ravindranath, N. H., Verardo, D. J., Dokken, D. J. (eds.) (2000): Intergovernmental Panel on Climate Change (IPCC). Land use, Land-use Change, and Forestry. A Special Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK, p. 377.
- Winjum, J. K., Brown, S., Schlamadinger, B. (1998): Forest harvests and wood products: Sources and sinks of atmospheric carbon dioxide. For. Sci. 44, 272–284.
- Woomer, P. L., Palm, C. A. (1998): An approach to estimating system carbon stocks in tropical forests and associated land uses. Commonwealth For. Rev. 77, 181–190.
- Woomer, P. L., Palm, C. A., Alegre, J., Castilla, C., Cordeiro, D. G., Hairiah, K., Kotto-Same, J., Moukam, A., Ricse, A., Rodrigues, V., van Noordwijk, M. (2000): Slash-and-burn effects on carbon stocks in the humid tropics, in Lal, R., Kimble, J. M., Stewart, B. A.: Global Climate Change and Tropical Ecosystems. Advances in Soil Science, CRC Press, Boca Raton, FL, USA. pp. 99–115.
- World Bank (2004): Carbon finance at the World Bank. http://carbonfinance.org/ (accessed Dec. 20, 2007).
- Zhaohua, Z., Mantang, C., Shiji, W., Youxu, J. (eds.) (1991): Agroforestry systems in China. Chinese Academy of Forestry, Beijing, and Int Dev Res Cent., Singapore, p. 216.
