Fluxes of nitrous oxide, methane and carbon dioxide during freezing-thawing cycles in an Inner Mongolian steppe
Fluxes of nitrous oxide, methane and carbon dioxide during freezing-thawing cycles in an Inner Mongolian steppe
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DOI：
10.1007/s11104-008-9610-8
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发表时间：
2008-07-01
期刊：
影响因子：
4.9
通讯作者：
Butterbach-Bahl, K.
中科院分区：
文献类型：
--
作者：
Holst, J.;Liu, C.;Butterbach-Bahl, K.
2006年冬春过渡期间，对内蒙古冬季放牧(WG)和未放牧草原(UG99)的一氧化二氮(N2O)、甲烷(CH4)和二氧化碳(CO2)的排放通量进行了跟踪研究。3月12日至5月11日期间，N2O的平均通量分别为8.2+/-0.5(Ug99)和1.5+/-0.2微克N2O-Nm(-2)h(-1)(Wg)。二氧化碳为7.2+/-0.2和3.0+/-0.1毫克CO2-Cm(-2)h(-1)(Wg)，CH4为-42.5+/-0.9(Ug99)和-14.1+/-0.3微克CH4-Cm(-2)h(-1)(Wg)。我们的数据表明，半干旱草原的N2O排放受到冻融的强烈影响。UG99站的N2O排放量高达75mgN2O-Nm(-2)h(-1)，但WG站的N2O排放量要低得多。观察到的未放牧和放牧地之间N2O、CH4和CO2通量的差异归因于放牧地植物生物量的减少，以及最重要的--由于冬季积雪减少而导致土壤水分的减少。因此，冬季放牧显著减少了N2O的排放，但另一方面也减少了大气CH4的吸收。为了最终评估这两种影响中哪一种对非二氧化碳温室气体平衡最重要，需要测量一整年的温室气体平衡。
Fluxes of nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) were followed at winter-grazed (WG) and ungrazed steppe (UG99) in Inner Mongolia during the winter-spring transition of 2006. Mean fluxes during the period March 12-May 11 were 8.2+/-0.5 (UG99) and 1.5+/-0.2 mu g N2O-N m(-2) h(-1) (WG) for N2O, 7.2+/-0.2 (UG99) and 3.0+/-0.1 mg CO2-C m(-2) h(-1) (WG) for CO2 and -42.5+/-0.9 (UG99) and -14.1+/-0.3 mu g CH4-C m(-2) h(-1) (WG) for CH4. Our data show that N2O emissions from semi-arid steppe are strongly affected by freeze-thawing. N2O emissions reached values of up to 75 mu g N2O-N m(-2) h(-1) at the UG99 site, but were considerably lower at the WG site. The observed differences in N2O, CH4 and CO2 fluxes between the ungrazed and grazed sites were ascribed to the reduced plant biomass at the grazed site, and-most important-to a reduction in soil moisture, due to reduced snow capturing during winter. Thus, winter-grazing significantly reduced N2O emission but on the other hand also reduced the uptake of atmospheric CH4. To finally evaluate which of the both effects is most important for the non-CO2 greenhouse gas balance measurements covering an entire year are needed.