Effects of nitrogen fertilization on the fluxes of N₂O, CH₄, and CO₂ from soils in a Florida slash pine plantation

Abstract

We measured fluxes of N2O, CH4 and CO2 from control and urea-nitrogen fertilized soils of a mature slash pine (Pinuselliottii var. elliottii Englem.) plantation in Alachua County, Florida. The fertilization did not affect CO2 emissions, but significantly increased the emissions of N2O and lowered the uptake of atmospheric CH4. Daily average N2O emissions from the fertilized soils were 8–600 times higher (12–74 μg N2O-N•m−2•h−1) than daily average N2O emissions from control soils (0.02–4.0 μg N2O-N•m−2•h−1). Daily average CH4 uptake by the fertilized soils were 5–20 times lower (0.001–0.007 mg CH4-C•m−2•h−1) than daily average CH4 uptake by control soils (0.015–0.035 mg CH4-C•m−2•h−1). We also measured the relative activities of the bacteria populations that were responsible for CH4 oxidation in the control and fertilized soils. Results from these measurements suggest that fertilization shifted the relative activities of the CH4 oxidizing bacteria from those dominated by methanotrophs in the control soils to those dominated by nitrifying bacteria in the surface (0–2 cm) of the fertilized soils. The shift in relative activities of these bacteria may have been responsible for the lower CH4 uptake by the fertilized soils.

The effects of management on soil and plant carbon sequestration in slash pine plantations

“…Similar results were reported for soils under ponderosa pine seedlings (Vose et al . 1995) and soils under mature slash pine plantations (Castro et al . 1994).…”

“…These two opposite effects caused simultaneously by fertilization can result in little or no overall change in below-ground CO 2 evolution rates. This might also be the underlying reason for the contrasting results of soil respiration responses to fertilization (Van Cleve & Moore 1978;Brumme & Beese 1992;Castro et al . 1994;Vose et al .…”

Nitrogen deposition and carbon sequestration in alpine meadows

“…Long-term N additions can reduce decomposition rates, along with increased lignin accumulation (Magill and Aber 1998). Meanwhile, other studies indicate that N deposition can increase (Ma˚nsson and Falkengren-grerup 2003;Gallardo and Schlesinger 1994), reduce (Arnebrant et al 1996;Aerts and de Caluwe 1999;Berg and Matner 1997;Fog 1988;Persson and Wiren 1989;Persson et al 2000) or have no significant influences on soil CO 2 emissions (Castro et al 1994).…”

Soil-Atmosphere CO Exchanges and Microbial Biogeochemistry of CO Transformations in a Brazilian Agricultural Ecosystem

“…Agriculture in particular impacts carbon, nitrogen, and phosphorous cycles, altering patterns of microbial activity and elemental distribution relative to what occurs in natural systems (see, e.g., references 16, 42, and 43). In addition, agriculture disturbs fluxes of methane, nitrous oxide, and nitric oxide (5,26,32,38,40,42,44). Each of these gases plays important roles in atmospheric radiative forcing and contributes significantly to greenhouse warming through various direct and indirect effects (15,37,45).…”