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Methane oxidation in successional and agricultural ecosystems: Effects of nitrogen, soil disturbance, and precipitation.
SUWANWAREE, PONGTHEP*,1, ROBERTSON, G2, 1 Michigan State University, Hickory Corners, MI2 Michigan State University, Hickory Corners, MI
ABSTRACT- We measured methane (CH4) oxidation in no-till agriculture, successional communites, and mature forests in southwest Michigan to test hypotheses about ecological controls on methane flux in well-aerated soils. To small plots in replicated communities we added inorganic nitrogen, physically disturbed the soil, or added water to simulate additional rainfall. We then measured in situ methane oxidation rates using static flux chambers for several weeks. Oxidation rates were highest in mid-successional sites (ca. 15 ug CH4-C m-2 h-1) and lowest in the agricultural sites (4-10 ug CH4-C m-2 h-1). Added nitrogen or water had no discernible effect on oxidation rates for several weeks following experimental additions; soil disturbance, on the other hand, significantly stimulated oxidation for a number of weeks but only in the mature forest site. Results from these and laboratory experiments suggest specific ecological controls on methane oxidation rates in these ecosystems.
KEY WORDS: methane, oxidation, arable soils, greebhouse gases