کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10846254 | 1070046 | 2005 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
CH4 oxidation and N2O emissions at varied soil water-filled pore spaces and headspace CH4 concentrations
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
دانش خاک شناسی
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
Emission of N2O and CH4 oxidation rates were measured from soils of contrasting (30-75%) water-filled pore space (WFPS). Oxidation rates of 13C-CH4 were determined after application of 10 μl 13C-CH4 lâ1 (10 at. % excess 13C) to soil headspace and comparisons made with estimates from changes in net CH4 emission in these treatments and under ambient CH4 where no 13C-CH4 had been applied. We found a significant effect of soil WFPS on 13C-CH4 oxidation rates and evidence for oxidation of 2.2 μg 13C-CH4 dâ1 occurring in the 75% WFPS soil, which may have been either aerobic oxidation occurring in aerobic microsites in this soil or anaerobic CH4 oxidation. The lowest 13C-CH4 oxidation rate was measured in the 30% WFPS soil and was attributed to inhibition of methanotroph activity in this dry soil. However, oxidation was lowest in the wetter soils when estimated from changes in concentration of 12+13C-CH4. Thus, both methanogenesis and CH4 oxidation may have been occurring simultaneously in these wet soils, indicating the advantage of using a stable isotope approach to determine oxidation rates. Application of 13C-CH4 at 10 μl 13C-CH4 lâ1 resulted in more rapid oxidation than under ambient CH4 conditions, suggesting CH4 oxidation in this soil was substrate limited, particularly in the wetter soils. Application of N14H415NO3 and N15H415NO3 (80 mg N kg soilâ1; 9.9 at.% excess 15N) to different replicates enabled determination of the respective contributions of nitrification and denitrification to N2O emissions. The highest N2O emission (119 μg 14+15N-N2O kg soilâ1 over 72 h) was measured from the 75% WFPS soil and was mostly produced during denitrification (18.1 μg 15N-N2O kg soilâ1; 90% of 15N-N2O from this treatment). Strong negative correlations between 14+15N-N2O emissions, denitrified 15N-N2O emissions and 13C-CH4 concentrations (r=â0.93 to â0.95, N2O; r=â0.87 to â0.95, denitrified 15N-N2O; P<0.05) suggest a close relationship between CH4 oxidation and denitrification in our soil, the nature of which requires further investigation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Soil Biology and Biochemistry - Volume 37, Issue 10, October 2005, Pages 1785-1794
Journal: Soil Biology and Biochemistry - Volume 37, Issue 10, October 2005, Pages 1785-1794
نویسندگان
M.I. Khalil, E.M. Baggs,