Water, Air, & Soil Pollution

, Volume 220, Issue 1–4, pp 213–223 | Cite as

Effects of Vegetation Removal and Urea Application on Iron and Nitrogen Redox Chemistry in Riparian Forested Soils

  • Junu Shrestha
  • Jean Christophe Clément
  • Joan G. Ehrenfeld
  • Peter R. JaffeEmail author


Riparian wetlands are subject to nitrogen enrichment from upgradient agricultural and urban land uses and also from flooding by nitrogen-enriched surface waters. The effects of this N enrichment on wetland soil biogeochemistry may be mediated by both the presence of plants and the presence of redox-active compounds, specifically iron oxides in the soil. Despite the extensive research on wetland N cycling, the relative importance of these two factors on nitrogen is poorly known, especially for forested wetlands. This study evaluates the responses of the N and the Fe cycles to N enrichment in a riparian forested wetland, contrasting vegetated field plots with plots where the vegetation was removed to test the role of plants. Furthermore, in vitro anaerobic incubations of the experimental soils were performed to track Fe chemical changes over time under anoxic or flooded conditions. Wetland soils treated with N in form of urea, as expected, had significantly higher amounts inorganic nitrogen. In the soils where vegetation was also removed, in addition to inorganic nitrogen pool, increase in organic nitrogen pool was also observed. The results demonstrate the role of vegetation in limiting the effects excess urea has on different soil nitrogen pools. Results from anaerobic incubation of the experimental soils demonstrated the effects of N enrichment on the wetland Fe cycle. The effects of excess nitrogen and the role of vegetation on the Fe cycle in riparian wetland soil became more evident during anaerobic incubation experiments. At the end of the field experiment, Fe concentrations in the soils under the treatments were not significantly different from the control soils at the 5% confidence level. However, during the anaerobic incubation experiment of soils collected at the end of the experiment from these plots, the N-enriched soils and the unvegetated soils maintained significantly elevated concentrations of reducible Fe(III) for the initial 2-week period of incubation, and the soils collected from the plots with both the treatments had the highest Fe(III) concentrations. After 20 days of incubation, however, the Fe(III) concentrations decreased to the similar concentrations in all the incubated soils. The study clarifies the roles vegetation play in mediating the effects of N enrichment and also demonstrates that N enrichment does affect wetland redox cycle, which has strong implications on ecosystem services such as water quality improvement.


Nitrogen Iron Riparian Wetland Soil Vegetation 


  1. Anderson, R. T., & Lovley, D. R. (2000). Anaerobic bioremediation of benzene under sulfate reducing conditions in a petroleum-contaminated aquifer. Environmental Science and Technology, 11, 2261–2266.CrossRefGoogle Scholar
  2. Armstrong, J., & Armstrong, W. (2001). Rice and Phragmites: Effects of organic acids on growth, root permeability, and radial oxygen loss to the rhizosphere. American Journal of Botany, 88(8), 1359–1370.CrossRefGoogle Scholar
  3. Bechtold, J. S., Edwards, R. T., & Naiman, R. J. (2003). Biotic versus hydrologic control over seasonal nitrate leaching in a floodplain forest. Biogeochemistry, 63, 53–71.CrossRefGoogle Scholar
  4. Benz, M., Brune, A., & Schink, B. (1998). Anaerobic and aerobic oxidation of ferrous iron at neutral pH by chemoheterotrophic nitrate-reducing bacteria. Archives of Microbiology, 169, 159–165.CrossRefGoogle Scholar
  5. Bernhardt, E. S., & Likens, G. E. (2002). Dissolved organic carbon enrichment alters nitrogen dynamics in a forest stream. Ecology, 83(6), 1689–1700.CrossRefGoogle Scholar
  6. Boyer, E. W., Goodale, C. L., Jaworsk, N. A., & Howarth, R. W. (2002). Anthropogenic nitrogen sources and relationships to riverine nitrogen export in the northeastern USA. Biogeochemistry, 57(1), 137–169.CrossRefGoogle Scholar
  7. Clément, J. C., Shrestha, J., Ehrenfeld, & Jaffe, P. R. (2005). Ammonium oxidation coupled to dissimilatory reduction of iron under anaerobic conditions in wetland soils. Soil Biology and Biochemistry, 37, 2323–2328.CrossRefGoogle Scholar
  8. Cruz, C., & Loucao, M. A. M. (2002). Comparison of methodologies for nitrate determination in plants and soils. Journal of Plant Nutrition, 25(6), 1185–1211.CrossRefGoogle Scholar
  9. Dakora, F. D., & Phillips, D. A. (2002). Root exudates as mediators of mineral acquisition in low-nutrient environments. Plant and Soil, 245, 35–47.CrossRefGoogle Scholar
  10. Dunn, R. M., Mikola, J., Bol, R., & Bardgett, R. D. (2006). Influence of microbial activity on plant–microbial competition for organic and inorganic nitrogen. Plant and Soil, 289, 321–334.CrossRefGoogle Scholar
  11. Emmett, B. A., Kjonaas, O. J., Gundersen, P., Koopmans, C., Tietema, A., & Sleep, D. (1998). Natural abundance of N-15 in forests across a nitrogen deposition gradient. Forest Ecology and Management, 101(1–3), 9–18.CrossRefGoogle Scholar
  12. Frank, D. A., & Groffman, P. M. (2009). Plant rhizospheric N processes: What we don’t know and why we should care. Ecology, 90(6), 1512–1519.CrossRefGoogle Scholar
  13. Galloway, J. N., Townsend, A. R., Erisman, J. W., Bekunda, M., Cai, Z., Freney, J. R., et al. (2008). Transformation of the nitrogen cycle: Recent trends, questions and potential solutions. Science, 320, 889–892.CrossRefGoogle Scholar
  14. Greenberg, A. E., Clesceri, L. S., & Eaton, A. D. (1992). Standard methods for the examination of water and wastewater (18th ed., pp. 392–393). Washington: American Public Health Association. 418 A.Google Scholar
  15. Gundersen, P., Emmett, B. A., Kjonaas, O. J., Koopmans, C. J., & Tietema, A. (1998). Impact of nitrogen deposition on nitrogen cycling in forests: A synthesis of NITREX data. Forest Ecology and Management, 101(1–3), 37–55.CrossRefGoogle Scholar
  16. Harrison, K. A., Bol, R., & Bardgett, R. D. (2007). Preferences for different nitrogen forms by coexisting plant species and soil microbes. Ecology, 88, 989–999.CrossRefGoogle Scholar
  17. Hefting, M. M., Clement, J. C., Bienkowski, P., Dowrick, D., Guenat, C., Butturini, A., et al. (2005). The role of vegetation and litter in the nitrogen dynamics of riparian buffer zones in Europe. Ecological Engineering, 24(5), 465–482.CrossRefGoogle Scholar
  18. Herlihy, A. T., Stoddard, J. L., & Johnson, C. B. (1998). The relationship between stream chemistry and watershed land use data in the mid-Atlantic region, U.S. water air and soil. Pollution, 105, 377–386.CrossRefGoogle Scholar
  19. Hernandez, M. E., & Mitsch, W. J. (2007). Denitrification potential and organic matter as affected by vegetation community, wetland age, and plant introduction in created wetlands. Journal of Environmental Quality, 36(1), 333–342.CrossRefGoogle Scholar
  20. Hill, A. R. (1996). Nitrate removal in stream riparian zones. Journal of Environmental Quality, 25(4), 743–755.CrossRefGoogle Scholar
  21. Hogan, D. M., & Walbridge, M. R. (2007). Best management practices for nutrient and sediment retention in urban stormwater runoff. Journal of Environmental Quality, 36, 386–395.CrossRefGoogle Scholar
  22. Howarth, R. W., Billen, G., Swaney, D., Townsend, A., Jaworski, N., Lajtha, K., et al. (1996). Regional nitrogen budgets and riverine N&P fluxes for the drainages to the North Atlantic Ocean: Natural and human influences. Biogeochemistry, 35(1), 75–139.CrossRefGoogle Scholar
  23. Jackel, U., & Schnell, S. (2000). Suppression of methane emission from rice paddies by ferric iron fertilization. Soil Biology & Biochemistry, 32(11–12), 1811–1814.CrossRefGoogle Scholar
  24. Jones, D. L., & Hinsinger, P. (2008). The rhizosphere: Complex by design. Plant and Soil, 312, 1–6.CrossRefGoogle Scholar
  25. Jordan, T. E., Correll, D. L., & Weller, D. E. (1997). Effects of agriculture on discharges of nutrients from coastal plain watersheds of Chesapeake Bay. Journal of Environmental Quality, 26(3), 836–848.CrossRefGoogle Scholar
  26. Keeney, D. R., & Nelson, D. W. (1982). Nitrogen-inorganic forms. In A. L. Page (Ed.), Methods of soil analysis, part 2. Agronomy 9 (2nd ed., pp. 643–698). Madison: ASA, SSSA.Google Scholar
  27. Koroleff, F. (1983). Simultaneous oxidation of nitrogen and phosphorus compounds by persulfate. In K. Grasshoff, M. Eberhardt, & K. Kremling (Eds.), Methods of seawater analysis (pp. 168–169). Weinheimer: Verlag Chemie.Google Scholar
  28. Kostka, J. E., Gribsholt, B., Petrie, E., Dalton, D., Skelton, H., & Kristensen, E. (2002). The rates and pathways of carbon oxidation in bioturbated saltmarsh sediments. Limnology and Oceanography, 47(1), 230–240.CrossRefGoogle Scholar
  29. Kulkarni, M. V., Groffman, P. M., & Yavitt, J. B. (2008). Solving the global nitrogen problem: It’s a gas! Frontiers in Ecology and the Environment, 6, 199–206.CrossRefGoogle Scholar
  30. Lovley, D. R., & Phillips, E. J. P. (1986). Organic-matter mineralization with reduction of ferric iron in anaerobic sediments. Applied and Environmental Microbiology, 51(4), 683–689.Google Scholar
  31. Lovley, D. R., & Phillips, E. J. P. (1987). Rapid assay for microbially reducible ferric iron in aquatic sediments. Applied and Environmental Microbiology, 53, 1536–1540.Google Scholar
  32. Mayer, P. M., Reynolds, S. K., McCutchen, M. D., & Canfield, T. J. (2007). Meta-analysis of nitrogen removal in riparian buffers. Journal of Environmental Quality, 36, 1172–1180.CrossRefGoogle Scholar
  33. McDowell, W. H., Magill, A. H., Aitkenhead-Peterson, J. A., Aber, J. D., Merriam, J. L., & Kaushal, S. S. (2004). Effects of chronic nitrogen amendment on dissolved organic matter and inorganic nitrogen in soil solution. Forest Ecology and Management, 196(1), 29–41.CrossRefGoogle Scholar
  34. McNulty, S. G., Aber, J. D., McLellan, T. M., & Katt, S. M. (1990). Nitrogen cycling in high elevation forests of the Northeastern United-States in relation to nitrogen deposition. Ambio, 19(1), 38–40.Google Scholar
  35. Megonigal, J. P., & Day, F. P. (1992). Effects of flooding on root and shoot production of bald cypress in large experimental enclosures. Ecology, 73(4), 1182–1193.CrossRefGoogle Scholar
  36. Mulholland, P. J., Tank, J. L., Sanzone, D. M., Wollheim, W. M., Peterson, B. J., Webster, J. R., et al. (2000). Nitrogen cycling in a forest stream determined by a N-15 tracer addition. Ecological Monographs, 70(3), 471–493.Google Scholar
  37. Nealson, K. H., Belz, A., & McKee, B. (2002). Breathing metals as a way of life: Geobiology in action. Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology, 81(1–4), 215–222.CrossRefGoogle Scholar
  38. Neubauer, S. C., Emerson, D., & Megonigal, J. P. (2002). Life at the energetic edge: Kinetics of circumneutral iron oxidation by lithotrophic iron-oxidizing bacteria isolated from the wetland-plant rhizosphere. Applied and Environmental Microbiology, 68(8), 3988–3995.CrossRefGoogle Scholar
  39. Peterson, B. J., Bahr, M., & Kling, G. W. (1997). A tracer investigation of nitrogen cycling in a pristine tundra river. Canadian Journal of Fisheries and Aquatic Sciences, 54(10), 2361–2367.Google Scholar
  40. Pezeshki, S. R. (2001). Wetland plant responses to soil flooding. Environmental and Experimental Botany, 46(3), 299–312.CrossRefGoogle Scholar
  41. Pinton, R., Varanini, Z., & Nannipieri, P. (Eds.). (2007). The rhizosphere: Biochemistry and organic substances at the soil–plant interface (2nd ed.). Boca Raton: CRC.Google Scholar
  42. Ponnamperuma, F. N. (1972). The chemistry of submerged soils. Advances in Agronomy, 24, 29–96.CrossRefGoogle Scholar
  43. Raastad, I. A., & Mulder, J. (1999). Dissolved organic matter (DOM) in acid forest soils at Gardsjon (Sweden): Natural variabilities and effects of increased input of nitrogen and of reversal of acidification. Water Air and Soil Pollution, 114(1–2), 199–219.CrossRefGoogle Scholar
  44. Ratering, S., & Schnell, S. (2001). Nitrate-dependent iron (II) oxidation in paddy soil. Environmental Microbiology, 3, 100–109.CrossRefGoogle Scholar
  45. Reddy, K. R., & DeLaune, R. D. (2008). Biogeochemistry of wetlands: Science and applications. Boca Raton: CRC.CrossRefGoogle Scholar
  46. Reddy, K., D’Angelo, E. M., & DeBusk, T. A. (1990). Oxygen transport through aquatic macrophytes: The role in wastewater treatment. Journal of Environmental Quality, 19(2), 261–267.CrossRefGoogle Scholar
  47. Sahrawat, K. L. (2004). Ammonium production in submerged soils and sediments: The role of reducible iron. Communications in Soil Science and Plant Analysis, 35(3–4), 399–411.CrossRefGoogle Scholar
  48. Schimel, J. P., & Bennett, J. (2004). Nitrogen mineralization: Challenges of a changing paradigm. Ecology, 85, 591–602.CrossRefGoogle Scholar
  49. Senn, D. B., & Hemond, H. F. (2002). Nitrate controls on iron and arsenic in an urban lake. Science, 296(5577), 2373–2376.CrossRefGoogle Scholar
  50. Shrestha, J., Rich, J. J., Ehrenfeld, J. G., & Jaffe, P. R. (2009). Oxidation of ammonium to nitrite under iron-reducing conditions in wetland soils: Laboratory, field demonstrations, and push-pull rate determination. Soil Science, 174, 156–164.CrossRefGoogle Scholar
  51. Stanley, E. H., & Maxted, J. T. (2008). Changes in the dissolved nitrogen pool across land cover gradients in Wisconsin streams. Ecological Applications, 18, 1579–1590.CrossRefGoogle Scholar
  52. Straub, K. L., Benz, M., Schink, B., & Widdel, F. (1996). Anaerobic, nitrate-dependent microbial oxidation of ferrous iron. Applied and Environmental Microbiology, 62(4), 1458–1460.Google Scholar
  53. Stuanes, A. O., & Kjonaas, O. J. (1998). Soil solution chemistry during four years of NH4NO3 addition to a forested catchment at Gardsjon, Sweden. Forest Ecology and Management, 101(1–3), 215–226.CrossRefGoogle Scholar
  54. Vepraskas, M. J. (2000). Morphological features of seasonally reduced soils. In J. L. Richardson & M. J. Vepraskas (ed.), Wetland soils: Genesis, hydrology, landscapes, and classification (pp. 163–182). Boca Raton, FL: Lewis Publ.Google Scholar
  55. Vitousek, P. M., Aber, J. D., Howarth, R. W., Likens, G. E., Matson, P. A., Schindler, D. W., et al. (1997). Human alteration of the global nitrogen cycle: Sources and consequences. Ecological Applications, 7, 737–750.Google Scholar
  56. Walker, T. S., Bais, H. P., Grotewold, E., & Vicanco, J. M. (2003). Root exudation and rhizosphere biology. Plant Physiology, 132, 44–51.CrossRefGoogle Scholar
  57. Yu, Z. S., Kraus, T. E. C., Dahlgren, R. A., Horwath, W. R., & Zasoski, R. J. (2003). Mineral and dissolved organic nitrogen dynamics along a soil acidity-fertility gradient. Soil Science Society of America Journal, 67(3), 878–888.Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • Junu Shrestha
    • 1
  • Jean Christophe Clément
    • 2
  • Joan G. Ehrenfeld
    • 3
  • Peter R. Jaffe
    • 1
    Email author
  1. 1.Department of Civil and Environmental EngineeringPrinceton UniversityPrincetonUSA
  2. 2.Laboratoire d’Ecologie Alpine, UMR CNRS 5553Université Joseph FourierGrenoble Cedex 9France
  3. 3.Department of Ecology, Evolution & Natural Resources, Cook CollegeRutgers UniversityNew BrunswickUSA

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