, Volume 128, Issue 1–2, pp 257–266 | Cite as

Denitrification in a subtropical, semi-arid North American savanna: field measurements and intact soil core incubations

  • Fiona M. SoperEmail author
  • Peter M. Groffman
  • Jed P. Sparks


Information on denitrification (particularly N2) losses from dry ecosystems is limited despite their large area. Here, we present the first direct denitrification measurements for a northern hemisphere savanna, a Prosopis-dominated grassland/grove matrix in south Texas. We used the gas-flow intact soil core method to quantify N2, N2O and CO2 losses and compared these with field measurements of N2O, NOy, NH3 and CO2. Under field-realistic soil moisture and O2 conditions (average 17.5–20 % O2, minimum 15 %) incubated soils produced no measurable N2 flux (detection limit 52.2 µg N m−2 h−1). Only in a subset of grove soils were fluxes of 70–75 µg N m−2 h−1 recorded after 102 h of incubation at 5–10 % O2 following wetting of very dry soils. Making the assumption that potential N2 production falls just below the detection limit (likely an overestimate given the conditions needed to generate measurable fluxes), N2 flux rates would fall on the low end of that recorded for a tropical Australian savanna (45–110 µg N m−2 h−1) under comparable abiotic conditions. Assuming maximum possible production rates, N2 could comprise <32–76 % of total soil N gas flux following soil wetting in summer. Lack of flux response to soil wetting in winter suggests that cold-season N2 fluxes are negligible. N2O fluxes for core incubations were significantly higher than for field chambers; thus it is likely that incubations may overestimate N2O flux by reducing soil column consumption. Overall, results indicate that soil N2 fluxes are less dominant in this savanna than in other ecosystems investigated.


Grassland N-FARM di-nitrogen Nitrous oxide Nitric oxide Prosopis 



We thank Shauntle Barley for assistance with sample collection, Kimberlee Sparks, John Pollak, Collin Edwards, David Lewis and Lisa Martel for technical support, and David and Stacy McKown for field logistics. This work was supported a National Science Foundation Doctoral Dissertation Improvement Grant to JPS (Award #1309124), Sigma Xi (Cornell chapter), the Cornell University Betty Miller Francis’47 Fund for Field Research, the Andrew W. Mellon Foundation and the Cornell University Program in Cross-Scale Biogeochemistry and Climate (supported by NSF-IGERT and the Atkinson Center for a Sustainable Future).

Author contributions

FMS, JPS, and PMG formulated the original idea and developed methodology, FMS and JPS conducted field sampling, FMS performed sample analysis and statistical analysis and FMS, PMG and JPS interpreted data and wrote the manuscript.

Supplementary material

10533_2016_205_MOESM1_ESM.docx (58 kb)
Supplementary material 1 (DOCX 57 kb)


  1. Archer S, Boutton T, Hibbard K (2001) Trees in grasslands: biogeochemical consequences of woody plant expansion. In: Schulze E-D, Harrison M, Heimann M et al (eds) Global biogeochemical cycles in the climate system. Academic Press, San Diego, pp 115–138CrossRefGoogle Scholar
  2. Austin A, Yahdjian L, Stark J et al (2004) Water pulses and biogeochemical cycles in arid and semiarid ecosystems. Oecologia 141:221–235. doi: 10.1007/s00442-004-1519-1 CrossRefGoogle Scholar
  3. Boutton TW, Liao JD (2010) Changes in soil nitrogen storage and δ15N with woody plant encroachment in a subtropical savanna parkland landscape. J Geophys Res 115:G03019. doi: 10.1029/2009JG001184 Google Scholar
  4. Burgin AJ, Groffman PM (2012) Soil O2 controls denitrification rates and N2O yield in a riparian wetland. J Geophys Res 117:G01010. doi: 10.1029/2011JG001799 Google Scholar
  5. Burgin AJ, Groffman PM, Lewis DN (2010) Factors regulating denitrification in a riparian wetland. Soil Sci Soc Am J 74:1826–1833. doi: 10.2136/sssaj2009.0463 CrossRefGoogle Scholar
  6. Butterbach-Bahl K, Willibald G, Papen H (2002) Soil core method for direct simultaneous determination of N2 and N2O emissions from forest soils. Plant Soil 240:105–116. doi: 10.1023/A:1015870518723 CrossRefGoogle Scholar
  7. Butterbach-Bahl K, Kock M, Willibald G et al (2004) Temporal variations of fluxes of NO, NO2, N2O, CO2, and CH4 in a tropical rain forest ecosystem. Glob Biogeochem Cycles. doi: 10.1029/2004GB002243 Google Scholar
  8. Clough TJ, Sherlock RR, Rolston DE (2005) A review of the movement and fate of N2O in the subsoil. Nutr Cycl Agroecosys 72:3–11. doi: 10.1007/s10705-004-7349-z CrossRefGoogle Scholar
  9. Dannenmann M, Butterbach-Bahl K, Gasche R et al (2008) Dinitrogen emissions and the N2:N2O emission ratio of a Rendzic Leptosol as influenced by pH and forest thinning. Soil Biol Biogeochem 40:2317–2323. doi: 10.1016/j.soilbio.2008.05.009 CrossRefGoogle Scholar
  10. Dannenmann M, Willibald G, Sippel S, Butterbach-Bahl K (2011) Nitrogen dynamics at undisturbed and burned Mediterranean shrublands of Salento Peninsula, Southern Italy. Plant Soil 343:5–15. doi: 10.1007/s11104-010-0541-9 CrossRefGoogle Scholar
  11. Davidson EA, Vitousek PM, Riley R et al (1991) Soil emissions of nitric oxide in a seasonally dry tropical forest of Mexico. J Geophys Res 96:15439. doi: 10.1029/91JD01476 CrossRefGoogle Scholar
  12. Davidson E, Matson P, Vitousek P et al (1993) Processes regulating soil emissions of NO and N2O in a seasonally dry tropical forest. Ecology 74:130–139. doi: 10.2307/1939508 CrossRefGoogle Scholar
  13. Eickenscheidt T, Heinichen J, Augustin J et al (2014) Nitrogen mineralization and gaseous nitrogen losses from waterlogged and drained organic soils in a black alder (Alnus glutinosa (L.) Gaertn.) forest. Biogeosciences 11:2961–2976. doi: 10.5194/bg-11-2961-2014 CrossRefGoogle Scholar
  14. Firestone MK (1982) Biological Denitrification. In: Stevenson FJ (ed) Nitrogen in agricultural soils. Soil Science Society of America, Madison, pp 289–326Google Scholar
  15. Galbally IE, Kirstine WV, Meyer CPM, Wang YP (2008) Soil-atmosphere trace gas exchange in semiarid and arid zones. J Environ Qual 37:599–607. doi: 10.2134/jeq2006.0445 CrossRefGoogle Scholar
  16. Garcia-Pichel F, Belnap J (1996) Microenvironments and microscale productivity of cyanobacterial desert crusts. J Phycol 32:774–782. doi: 10.1111/j.0022-3646.1996.00774.x CrossRefGoogle Scholar
  17. Groffman P, Brumme R, Butterbach-Bahl K et al (2000) Evaluating annual nitrous oxide fluxes at the ecosystem scale. Glob Biogeochem Cycles 14:1061–1070. doi: 10.1029/1999GB001227 CrossRefGoogle Scholar
  18. Groffman P, Altabet M, Böhlke J et al (2006) Methods for measuring denitrification: diverse approaches to a difficult problem. Ecol App 16:2091–2122. doi: 10.1890/1051-0761 CrossRefGoogle Scholar
  19. Groffman P, Butterbach-Bahl K, Fulweiler R et al (2009) Challenges to incorporating spatially and temporally explicit phenomena (hotspots and hot moments) in denitrification models. Biogeochemistry 93:49–77. doi: 10.1007/s10533-008-9277-5 CrossRefGoogle Scholar
  20. Hartley A, Barger N, Belnap J, Oskin G (2007) Dryland ecosystems. In: Marschner P, Rengel Z (eds) Nutrient cycling in terrestrial ecosystems: soil biology, vol 10. Springer, Berlin, pp 271–307CrossRefGoogle Scholar
  21. Hibbard K, Archer S, Schimel D, Valentine D (2001) Biogeochemical changes accompanying woody plant encroachment in a subtropical savanna. Ecology 82:1999–2011CrossRefGoogle Scholar
  22. Hutley L, Setterfield S (2008) Savanna. In: Jorgensen SE, Fath BD (eds) Encyclopedia of Ecology. Elsevier, Oxford, pp 3143–3154CrossRefGoogle Scholar
  23. Kulkarni MV, Groffman PM, Yavitt JB (2008) Solving the global nitrogen problem: it’s a gas! Front Ecol Environ 6:199–206. doi: 10.1890/060163 CrossRefGoogle Scholar
  24. Kulkarni MV, Burgin AJ, Groffman PM, Yavitt JB (2013) Direct flux and 15N tracer methods for measuring denitrification in forest soils. Biogeochemistry 117:359–373. doi: 10.1007/s10533-013-9876-7 CrossRefGoogle Scholar
  25. Liu F, Wu X, Bai E et al (2010) Spatial scaling of ecosystem C and N in a subtropical savanna landscape. Glob Change Biol 16:2213–2223. doi: 10.1111/j.1365-2486.2009.02099.x CrossRefGoogle Scholar
  26. McCalley CK, Strahm BD, Sparks KL et al (2011) The effect of long-term exposure to elevated CO2 on nitrogen gas emissions from Mojave Desert soils. J Geophys Res 116:G03022. doi: 10.1029/2011JG001667 Google Scholar
  27. Morse JL, Duran J, Beall F, Enanga E, Creed IF, Fernandez IJ, Groffman PM (2015a) Soil denitrification fluxes from three northeastern North American across a range of nitrogen deposition. Oecologia 177:17–27. doi: 10.1007/s00442-014-3117-1 CrossRefGoogle Scholar
  28. Morse JL, Duran J, Groffman PM (2015b) Denitrification and greenhouse gas fluxes in a northern hardwood forest: the importance of snowmelt and implications for ecosystem N budgets. Ecosystems 18:520–532. doi: 10.1007/s10021-015-9844-2 CrossRefGoogle Scholar
  29. Moulin AP, Glenn A, Tenuta M et al (2014) Alternative transformations of nitrous oxide soil flux data to normal distributions. Can J Soil Sci 94:105–108. doi: 10.4141/cjss2013-008 CrossRefGoogle Scholar
  30. Peterjohn W, Schlesinger W (1991) Factors controlling denitrification in a Chihuahuan desert ecosystem. Soil Sci Soc Am J 55:1694–1701. doi: 10.2136/sssaj1991.03615995005500060032x CrossRefGoogle Scholar
  31. Pinder RW, Bettez ND, Bonan GB et al (2012) Impacts of human alteration of the nitrogen cycle in the US on radiative forcing. Biogeochemistry 114:25–40. doi: 10.1007/s10533-012-9787-z CrossRefGoogle Scholar
  32. R Core Team (2013) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria.
  33. Raciti SM, Burgin AJ, Groffman PM et al (2011) Denitrification in Suburban Lawn Soils. J Environ Qual 40:1932–1940. doi: 10.2134/jeq2011.0107 CrossRefGoogle Scholar
  34. Saggar S, Jha N, Deslippe J et al (2013) Denitrification and N2O:N2 production in temperate grasslands: Processes, measurements, modelling and mitigating negative impacts. Sci Total Environ 465:173–195. doi: 10.1016/j.scitotenv.2012.11.050 CrossRefGoogle Scholar
  35. Schimel DS (2010) Drylands in the Earth System. Science 327:418–419. doi: 10.1126/science.1184946 CrossRefGoogle Scholar
  36. Schlesinger WH (2013) An estimate of the global sink for nitrous oxide in soils. Glob Change Biol 19:2929–2931. doi: 10.1111/gcb.12239 CrossRefGoogle Scholar
  37. Scholefield D, Hawkins J, Jackson SM (1997) Development of a helium atmosphere soil incubation technique for direct measurement of nitrous oxide and dinitrogen fluxes during denitrification. Soil Biol Biochem 29:1345–1352. doi: 10.1016/S0038-0717(97)00021-7 CrossRefGoogle Scholar
  38. Schwinning S, Sala O (2004) Hierarchy of responses to resource pulses in arid and semi-arid ecosystems. Oecologia 141:1–10. doi: 10.1007/s00442-004-1520-8 CrossRefGoogle Scholar
  39. Simek M, Jisova L, Hopkins DW (2002) What is the so-called optimum pH for denitrification in soil? Soil Biol Biochem 34:1227–1234. doi: 10.1016/S0038-0717(02)00059-7 CrossRefGoogle Scholar
  40. Soper FM, Boutton TW, Groffman PM, Sparks JP (2016) Nitrogen trace gas fluxes from a semi-arid subtropical savanna under woody legume encroachment. Glob Biogeochem Cycles 30. doi: 10.1002/2015GB005298
  41. Wang R, Willibald G, Feng Q et al (2011) Measurement of N2, N2O, NO, and CO2 emissions from soil with the gas-flow-soil-core technique. Environ Sci Tech 45:6066–6072. doi: 10.1021/es1036578 CrossRefGoogle Scholar
  42. Weier K, Doran J, Power J, Walters D (1993) Denitrification and the dinitrogen/nitrous oxide ratio as affected by soil water, available carbon, and nitrate. Soil Sci Soc Am J 57:66–72. doi: 10.2136/sssaj1993.03615995005700010013x CrossRefGoogle Scholar
  43. Werner C, Reiser K, Dannenmann M et al (2014) N2O, NO, N2, and CO2 emissions from tropical savanna and grassland of Northern Australia: an incubation experiment with intact soil cores. Biogeosci 11:6047–6065. doi: 10.5194/bg-11-6047-2014 CrossRefGoogle Scholar
  44. Wrage N, Velthof GL, van Beusichem ML, Oenema O (2001) Role of nitrifier denitrification in the production of nitrous oxide. Soil Biol Biochem 33:1723–1732. doi: 10.1016/S0038-0717(01)00096-7 CrossRefGoogle Scholar
  45. Yang W, McDowell AC, Brooks PD, Silver WL (2014) New high precision approach for measuring 15N–N2 gas fluxes from terrestrial ecosystems. Soil Biol Biochem 69:234–241. doi: 10.1016/j.soilbio.2013.11.009 CrossRefGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.Department of Ecology and Evolutionary BiologyCornell UniversityIthacaUSA
  2. 2.Cary Institute of Ecosystem StudiesMillbrookUSA

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