Plant and Soil

, Volume 288, Issue 1–2, pp 217–232 | Cite as

Effects of forest conversion into grassland on soil aggregate structure and carbon storage in Panama: evidence from soil carbon fractionation and stable isotopes

  • Luitgard Schwendenmann
  • Elise Pendall
Original Paper


Land-use and land-cover strongly influence soil properties such as the amount of soil organic carbon (SOC), aggregate structure and SOC turnover processes. We studied the effects of a vegetation shift from forest to grassland 90 years ago in soils derived from andesite material on Barro Colorado Island (BCI), Panama. We quantified the amount of carbon (C) and nitrogen (N) and determined the turnover of C in bulk soil, water stable aggregates (WSA) of different size classes (<53 μm, 53–250 μm, 250–2000 μm and 2000–8000 μm) and density fractions (free light fraction, intra-aggregate particulate organic matter and mineral associated soil organic C). Total SOC stocks (0–50 cm) under forest (84 Mg C ha−1) and grassland (64 Mg C ha−1) did not differ significantly. Our results revealed that vegetation type did not have an effect on aggregate structure and stability. The investigated soils at BCI did not show higher C and N concentrations in larger aggregates, indicating that organic material is not the major binding agent in these soils to form aggregates. Based on δ13C values and treating bulk soil as a single, homogenous C pool we estimated a mean residence time (MRT) of 69 years for the surface layer (0–5 cm). The MRT varied among the different SOC fractions and among depth. In 0–5 cm, MRT of intra-aggregate particulate organic matter (iPOM) was 29 years; whereas mineral associated soil organic C (mSOC) had a MRT of 124 years. These soils have substantial resilience to C and N losses because the >90% of C and N is associated with mSOC, which has a comparatively long MRT.


Density fractionation Forest conversion Grassland Mean residence time Soil organic carbon and nitrogen Stable carbon isotopes Tropical soil Water stable aggregates Panama 



This project benefited from field and laboratory assistance from Marco Valdez, Brandy Cline, and Ian Abernethy. Thanks to Robert F. Stallard for introducing us to the study sites and George F. Vance for laboratory use. We thank Mark Larson for his help with the stable isotope analysis. Special thanks to Jonathan Anderson for his assistance with the soil fractionation. Ann E. Russell, Abbey Wick, Chris Neill and two anonymous reviewers provided helpful comments on the manuscript. Partial funding for the research was provided by the Smithsonian Tropical Research Institute, Wyoming NASA Space Grant Consortium, NASA Grant #NGT-40102, Wyoming NASA EPSCoR, NASA Grant #NCC5-578, and an International Travel Grant from the University of Wyoming to Elise Pendall.


  1. Balesdent J, Mariotti A (1996) Measurement of soil organic matter turnover using 13C natural abundance. In: Boutton TW, Yamasaki SI (Eds), Mass Spectrometry of Soils. Marcel Dekker, New York, pp 83–112Google Scholar
  2. Bird M, Kracht O, Derrien D, Zhou Y (2003) The effect of soil texture and roots on the stable carbon isotope composition of soil organic carbon. Aust J Soil Res 41:77–94CrossRefGoogle Scholar
  3. Brodowski S, John B, Flessa H, Amelung W (2006) Aggregate-occluded black carbon in soil. Eur J Soil Sci 57:539–546CrossRefGoogle Scholar
  4. Brown S, Lugo AE (1982) The storage and production of organic matter in tropical forests and their role in the global carbon cycle. Biotropica 14:161–187CrossRefGoogle Scholar
  5. Brown S, Lugo AE (1990) Effects of forest clearing and succession on the carbon and nitrogen content of soil in Puerto Rica and US Virgin Islands. Plant Soil 35:53–64CrossRefGoogle Scholar
  6. Cadisch G, Imhof H, Urquiaga S, Boddey RM, Giller KE (1996) Carbon turnover (δ13C) and nitrogen mineralization potential of particulate light soil organic matter after rainforest clearing. Soil Biol Biochem 28:1555–1567CrossRefGoogle Scholar
  7. Cambardella CA, Elliott ET (1992) Particulate soil organic matter changes across a grassland cultivation sequence. Soil Sci Soc Am J 56:777–783CrossRefGoogle Scholar
  8. Choné T, Andreux F, Correa JC, Volkoff B, Cerri CC (1991) Changes in organic matter in an Oxisol from the central Amazonian forest during eight years as pasture, determined by 13C composition. In: Berthelin J (ed) Diversity of Environmental Biogeochemistry. Elsevier, New York, pp 307–405Google Scholar
  9. Conant RT, Six J, Paustian K (2004) Land use effects on soil carbon fractions in the southeastern United States: II Change in soil carbon fractions along a forest pasture chronosequence. Biol Fertil Soils 40:194–200CrossRefGoogle Scholar
  10. Condit R, Robinson WD, Ibanez DR, Aguilar S, Sanjur A, Martinez R, Stallard RF, Garcia T, Angehr GR, Petit L, Wright SJ, Robinson TR, Heckadon-Moreno S (2001) The status of the Panama Canal watershed and its biodiversity at the beginning of the 21st century. BioScience 51:135–144CrossRefGoogle Scholar
  11. Desjardins T, Andreux F, Volkoff B, Cerri CC (1994) Organic carbon and 13C contents in soils and soil size-fractions, and their changes due to deforestation and pasture installation in eastern Amazonia. Geoderma 61:103–118CrossRefGoogle Scholar
  12. Desjardins T, Barros E, Sarrazin M, Girardin C, Mariotti A (2004) Effects of forest conversion to pasture on soil carbon and dynamics in Brazilian Amazonia. Agric Ecosyst Environ 103:365–373CrossRefGoogle Scholar
  13. Elliot ET (1986) Aggregate structure and carbon, nitrogen, and phosphorus in native and cultivated soils. Soil Sci Soc Am J 50:627–633CrossRefGoogle Scholar
  14. Elliott ET, Palm CA, Reuss DE, Monz CA (1991) Organic matter contained in soil aggregates from a tropical chronosequence: correction for sand and light fraction. Agric Ecosys Environ 34:443–451CrossRefGoogle Scholar
  15. FAO (2005) Global Forest Resources Assessment. FAO Forestry Paper 147, Food and Agriculture Organization of the United Nations, RomGoogle Scholar
  16. Feigl BJ, Melillo J, Cerri CC (1995) Changes in the origin and quality of soil organic matter after pasture introduction in Rondonia (Brazil). Plant Soil 175:21–29CrossRefGoogle Scholar
  17. Feller C, Beare MH (1997) Physical control of soil organic matter dynamics in the tropics. Geoderma 79:69–116CrossRefGoogle Scholar
  18. Friedli H, Lötscher H, Oeschger H, Siegenthaler U, Stauffer B (1986) Ice core record of 13C/12C ratio of atmospheric CO2 in the past two centuries. Nature 324:237–238CrossRefGoogle Scholar
  19. García-Oliva F, Gallardo Lancho JF, Montaño NM, Islas P (2006) Soil Carbon and nitrogen dynamics followed by a forest-to-pasture conversion in western Mexico. Agroforest Syst 66:93–100CrossRefGoogle Scholar
  20. Gee GW, Or D (2002) Particle-size Analysis. In: Dane H, Topp GC (eds), Methods of Soil Analysis. Part 4. Physical Methods. Number 5 in the Soil Science Society of America Book Series. Soil Science Society of America, Madison, WI, pp. 255–293Google Scholar
  21. Golchin A, Oades JM, Skjemstad JO, Clarke P (1995) Structural and dynamic properties of soil organic matter as reflected by 13C natural abundance, pyrolysis mass spectrometry and solid-state 13C NMR spectroscopy in density fractions of an Oxisol under forest and pasture. Aust J Soil Res 33:59–76CrossRefGoogle Scholar
  22. Hammond BW (1999) Saccharum spontaneum (Gramineae) in Panama: The physiology and ecology of invasion. In: Ashton MS, O’Hara JL, Hauff RD (eds), Protecting Watershed Areas: Case of the Panama Canal. The Haworth Press, Inc., Binghamton, NY pp 23–38Google Scholar
  23. Houghton RA (2003) Revised estimates of the annual net flux of carbon to the atmosphere from changes in land use and land management 1850–2000. Tellus 55B:378–390Google Scholar
  24. IPCC (2001) Climate change 2001: the scientific basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Houghton JT, Ding Y, Griggs DJ, Noguer M, van der Linden PJ, Dai X, Maskell K, Johnson CA (eds) Cambridge University Press, Cambridge, UKGoogle Scholar
  25. Jastrow JD, Boutton TW, Miller RM (1996) Carbon dynamics of aggregate-associated organic matter estimated by carbon-13 natural abundance. Soil Sci Soc Am J 60:801–807CrossRefGoogle Scholar
  26. Jobbagy EG, Jackson RB (2000) The vertical distribution of soil organic carbon and its relation to climate and vegetation. Ecol Appl 10:423–436Google Scholar
  27. John B, Yamashita T, Ludwig B, Flessa H (2005) Organic carbon storage in aggregate and density fractions of silty soils under different land use. Geoderma 128:63–79CrossRefGoogle Scholar
  28. Krull ES, Skjemstad JO, Graetz D, Grice K, Dunning W, Cook G, Parr JF (2003) 13C-depleted charcoal from C4 grasses and the role of occluded carbon in phytoliths. Org Geochem 34:1337–1352CrossRefGoogle Scholar
  29. Leigh EG Jr, Rand AS, Windsor DM (1996) The ecology of a tropical forest: seasonal rhythms and long-term changes. Second edition. Smithsonian Institution Press, Washington, DCGoogle Scholar
  30. Murty D, Kirschbaum MUF, McMurtrie RE, McGilvray H (2002) Does conversion of forest to agricultural land change soil carbon and nitrogen? A review of the literature. Global Change Biol 8:105–123CrossRefGoogle Scholar
  31. Nadelhoffer KJ, Fry B (1988) Controls on natural nitrogen-15 and carbon-13 abundances in forest soil organic matter. Soil Sci Soc Am J 52:1633–1640CrossRefGoogle Scholar
  32. Neill C, Fry B, Melillo JM, Steudler PA, Moraes JFL, Cerri CC (1996) Forest- and pasture-derived carbn contributions to carbon stocks and microbial respiration of tropical pasture soils. Oecologia 107:113–119CrossRefGoogle Scholar
  33. Oades JM, Waters A (1991) Aggregate hierarchy in soils. Aust J Soil Res 29:815–828CrossRefGoogle Scholar
  34. Phillips DL, Gregg JW (2001) Uncertainty in source partitioning using stable isotopes. Oecologia 127:171–179CrossRefGoogle Scholar
  35. Six J, Jastrow JD (2002) Soil organic matter turnover. In: Lal R (eds) Encyclopedia of Soil Science. Marcel Dekker, Inc., New York, pp 936–942Google Scholar
  36. Six J, Elliott ET, Paustian K, Doran JW (1998) Aggregation and soil organic matter accumulation in cultivated and native grassland soils. Soil Sci Soc Am J 62:1367–1377CrossRefGoogle Scholar
  37. Six J, Schultz PA, Jastrow JD, Merckx R (1999) Recycling of sodium polytungstate used in soil organic matter studies. Soil Biol Biochem 31:1193–1196CrossRefGoogle Scholar
  38. Six J, Paustian K, Elliott ET, Combrink C (2000) Soil structure and organic matter: I. Distribution of aggregate-size classes and aggregate-associated carbon. Soil Sci Soc Am J 64:681–689CrossRefGoogle Scholar
  39. Six J, Conant RT, Paul EA, Paustian K (2002) Stabilization mechanisms of soil organic matter: Implications for C-saturation of soils. Plant Soil 241:155–576CrossRefGoogle Scholar
  40. Skjemstad JO, Le Feuvre RP, Prebble RE (1990) Turnover of soil organic matter under pasture as determined by 13C natural abundance. Aust J Soil Res 28:267–276CrossRefGoogle Scholar
  41. Smith BN, Epstein S (1971) Two categories of 13C/12C ratios for higher plants. Plant Physiol 47:380–384PubMedCrossRefGoogle Scholar
  42. Solomon D, Fritsche F, Lehmann J, Tekalign M, Zech W (2002) Soil organic matter dynamics in the subhumid agroecosystems of the Ethiopian highlands: Evidence from natural 13C abundance and particle size-fractionation. Soil Sci Soc Am J 66:969–978CrossRefGoogle Scholar
  43. STRI (2006) BCI Climate Summary. Terrestrial-Environmental Sciences Program of the Smithsonian Tropical Research Institute summary_bci.htmGoogle Scholar
  44. Tisdall JM, Oades JM (1982) Organic matter and water-stable aggregates. J Soil Sci 33:141–163CrossRefGoogle Scholar
  45. Trumbore SE (1993) Comparison of carbon dynamics in tropical and temperate soils using radiocarbon measurements. Global Biogeochem Cy 7:275–290Google Scholar
  46. Trumbore SE, Davidson EA, Camargo PB, Nepstad DC, Martinelli LA (1995) Belowground cycling of carbon in forests and pastures of Eastern Amazonia. Global Biogeochem Cy 9:515–528CrossRefGoogle Scholar
  47. USDA-NRCS (1999) Soil Taxonomy. US Gov. Print Office, Washington, DCGoogle Scholar
  48. Veldkamp E (1994) Organic carbon turnover in three tropical soils under pasture after deforestation. Soil Sci Soc Am J 58:175–180CrossRefGoogle Scholar
  49. Volkoff B, Cerri CC (1987) Carbon isotopic fractionation in subtropical Brazilian grassland soils. Comparison with tropical forest soils. Plant Soil 27:27–31CrossRefGoogle Scholar
  50. Yavitt JB (2000) Nutrient dynamics of soil derived from different parent material on Barro Colorado Island, Panama. Biotropica 32:198–207Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  1. 1.Department of Tropical SilvicultureInstitute of Silviculture, University of GoettingenGoettingenGermany
  2. 2.Department of BotanyUniversity of WyomingLaramieUSA

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