Nitrous oxide production by denitrification and nitrification in temperate forest, grassland and agricultural soils
Nitrous oxide production by denitrification and nitrification in temperate forest, grassland and agricultural soils
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DOI：
10.1046/j.1365-2389.1998.4930495.x
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发表时间：
1998-09-01
影响因子：
4.2
通讯作者：
Ambus, P
中科院分区：
文献类型：
--
作者：
Ambus, P
氧化亚氮是在土壤中通过生物反硝化和硝化作用产生的。为了加深对土壤N2O通量产生过程的基本认识，对云杉林、山毛榉林、河滨草地、滨海草地和农田的反硝化和硝化作用产生N2O的过程进行了研究。在春季和秋季，分别在沿地形坡度的高处和低处采集样品，预计N2O通量最大。低地貌部位N2O产生量河岸草地为32~121 ng N cm(-3)h~(-1)，滨海草地为9~26 ng N cm(-3)h~(-1)，农田为135~195 ng N cm(-3)h~(-1)，是高地的10~100倍。分别为0.3和0.4ngN cm(-3)h(-1)和7和10ngN cm(-3)h(-1)。这些差异几乎肯定是因为地势低的土壤更潮湿，含有更多的有机质。两种林分的N2O产生量均小于1ngN cm(-3)h(-1)，受O2的强烈抑制，不受景观位置的影响。硝化作用贡献了河岸草原N2O总量的60%以上。在农业中，硝化作用产生的N2O在低位占总N2O的13-74%，在高位占10-88%。反硝化作用是滨海草地N2O的主要来源，秋季低位时，硝化作用产生的N2O占总N2O的60%。在土壤硝化潜力较小的两个森林中，反硝化作用是N2O的唯一来源。在其他地点，硝化和反硝化潜势都很大，且大小相同。结果强调，在模拟土壤N2O排放时，需要在工艺水平上区分硝化和反硝化作用，并在田间尺度上识别地形。
Nitrous oxide is produced in soils by biological denitrification and nitrification. To improve the fundamental understanding of the processes leading to N2O fluxes from soils, the production of N2O from denitrification and nitrification in spruce forest, beech forest, riparian grassland, coastal grassland and an agricultural field were studied. Samples were taken at a high and a low position along a topographic gradient in each site in the spring and autumn when the largest N2O fluxes were expected. They were incubated after being amended with N, and C2H2 was used as biological inhibitor to distinguish nitrification and denitrification.The N2O production in the low landscape position varied between 32 and 121 ng N cm(-3) h(-1) in the riparian grassland, 9 and 26 ng N cm(-3) h(-1) in the coastal grassland, and 135 and 195 ng N cm(-3) h(-1) in the agricultural field which was 10-100 times more than in the high positions where rates ranged between 3 and 5 ng N cm(-3) h(-1), 0.3 and 0.4 ng N cm(-3) h(-1), and 7 and 10 ng N cm(-3) h(-1), respectively. These differences almost certainly arose because the soil in the low positions was wetter and contained more organic matter. In the two forests N2O production was less than 1 ng N cm(-3) h(-1), strongly inhibited by O-2, and not influenced by landscape position. Nitrification contributed to more than 60% of total N2O production in the riparian grassland. In the agricultural held nitrification produced 13-74% of the total N2O in the low position, and 10-88% in the high position. Denitrification was the dominant source of N2O in the coastal grassland except at the low position in the autumn where nitrification produced 60% of the total N2O. In the two forests where the soil had small nitrification potentials denitrification was the only source of N2O. In the other sites nitrification and denitrification potentials were large and of identical magnitude. The results emphasize the need to separate nitrification and denitrification at the process level and to recognize topography at the field scale when modelling N2O effluxes from soil.