HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (14) Citing Articles via Google Scholar Google Scholar Articles by McLain, J. E.T. Articles by Martens, D. A. Search for Related Content PubMed Articles by McLain, J. E.T. Articles by Martens, D. A. GeoRef GeoRef Citation Agricola Articles by McLain, J. E.T. Articles by Martens, D. A. Related Collections Biogeochemical Processes Global Change Microbial Processes

Soil Biology & Biochemistry

Moisture Controls on Trace Gas Fluxes in Semiarid Riparian Soils

^a USDA-ARS, U.S. Water Conservation Lab., 4331 East Broadway Rd., Phoenix, AZ 85040
^b Dean A. Martens (deceased), USDA-ARS, Southwest Watershed Research Center, 2000 East Allen Rd., Tucson, AZ 85719

^* Corresponding author (jmclain{at}uswcl.ars.ag.gov)

Variability in seasonal soil moisture (SM) and temperature (T) can alter ecosystem/atmosphere exchange of the trace gases carbon dioxide (CO₂), nitrous oxide (N₂O), and methane (CH₄). This study reports the impact of year-round SM status on trace gas fluxes in three semiarid vegetation zones, mesquite (30 g organic C kg^–1 soil), open/forb (6 g organic C kg^–1 soil), and sacaton (18 g organic C kg^–1 soil) from July 2002–September 2003 in southeastern Arizona. Carbon dioxide and N₂O emissions were highly dependent on available SM and T. During the heavy rains of the 2002 monsoon (238 mm total rainfall), large differences in soil C content did not correlate with variations in CO₂ production, as efflux averaged 235.6 ± 39.5 mg CO₂ m^–2 h^–1 over all sites. In 2003, limited monsoon rain (95 mm total rainfall) reduced CO₂ emissions by 19% (mesquite), 40% (open), and 30% (sacaton), compared with 2002. Nitrous oxide emissions averaged 21.1 ± 13.4 (mesquite), 2.1 ± 4.4 (open), and 3.9 ± 5.2 µg N₂O m^–2 h^–1 (sacaton) during the 2002 monsoon. Limited monsoon 2003 rainfall reduced N₂O emissions by 47% in the mesquite, but N₂O production increased in the open (55%) and sacaton (5%) sites. Following a dry winter and spring 2002 (15 mm total rainfall), premonsoon CH₄ consumption at all sites was close to zero, but following monsoon moisture input, the CH₄ sink averaged 26.1 ± 6.3 µg CH₄ m^–2 h^–1 through April 2003. Laboratory incubations showed potentials for CH₄ oxidation from 0 to 45 cm, suggesting that as the soil surface dried, CH₄ oxidation activity shifted downward in the sandy soils. Predicted climate change shifts in annual precipitation from one dominated by summer monsoon rainfall to one with higher winter precipitation may reduce soil CO₂ and N₂O emissions while promoting CH₄ oxidation rates in semiarid riparian soils of the Southwest, potentially acting as a negative feedback for future global warming.

Abbreviations: GHG, green house gas • IPCC, Intergovernmental Panel on Climate Change

This article has been cited by other articles:

				R. K. Shrestha, R. Lal, and C. Penrose Greenhouse Gas Emissions and Global Warming Potential of Reclaimed Forest and Grassland Soils J. Environ. Qual., February 6, 2009; 38(2): 426 - 436. [Abstract] [Full Text] [PDF]

				R. T. Venterea and J. M. Baker Effects of Soil Physical Nonuniformity on Chamber-Based Gas Flux Estimates Soil Sci. Soc. Am. J., August 20, 2008; 72(5): 1410 - 1417. [Abstract] [Full Text] [PDF]

				S. Haile-Mariam, H. P. Collins, and S. S. Higgins Greenhouse Gas Fluxes from an Irrigated Sweet Corn (Zea mays L.)-Potato (Solanum tuberosum L.) Rotation J. Environ. Qual., May 1, 2008; 37(3): 759 - 771. [Abstract] [Full Text] [PDF]