Denitrification potential of organic, forest and grassland soils in the Ribble-Wyre and Conwy River catchments, UK.
Denitrification potential of organic, forest and grassland soils in the Ribble-Wyre and Conwy River catchments, UK.
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DOI：
10.1039/c3em00693j
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发表时间：
2014-06
期刊：
影响因子：
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通讯作者：
F. Sgouridis;S. Ullah
中科院分区：
文献类型：
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作者：
F. Sgouridis;S. Ullah
由于流域内不同的土地利用管理措施对反硝化作用的生物地球化学调节器的影响，土壤反硝化活动可能具有很大的变异性。为了在混合利用的农村集水区中验证这一假设，假设除其他外，反硝化活动的相对大小可能受到有机(泥炭沼泽、石南地和酸性草地)、森林(针叶和落叶)和草地(改良和半改良)农村土地利用类型之间的土壤硝酸盐梯度(从低到高)的调节。在实验室测定了英国两个集水区有机土壤、森林土壤和草地土壤的反硝化潜力。土地利用类型(p<；0.05)对DP有显著影响，其变化范围为0.02~63.3mgNm(-2)h(-1)。有机和森林土壤的DP平均值(1.08 mg Nm(-2)h(-1))分别比半改良(4.06 mg Nm(-2)h(-1))和改良(12.09 mg Nm(-2)h(-1))草地土壤的DP低3倍和10倍，其中硝态氮与DP呈正相关(p<；0.05)。结果表明，有机土壤和草地土壤硝酸盐浓度的差异部分调节了DP的程度。在没有氮肥的情况下，除大气氮沉降外，有机土壤和森林土壤的相对较低的净硝化势(作为反硝化菌的硝酸盐来源)似乎导致了与草原土壤相比反硝化菌的活性较低。此外，土壤有机碳、pH、容重、充满水的孔隙和质地之间的相互作用，因为这些都受到土地管理的相对程度的影响，对DP施加了额外的控制。结果表明，土地管理对反硝化有显著影响，因此在模拟和/或预测反硝化对土地利用变化的响应时，需要考虑土地管理的影响。
Soil denitrification activity can be highly variable due to the effects of varied land use management practices within catchments on the biogeochemical regulators of denitrification. To test this assumption in the context of mixed-use rural catchments, it was hypothesised that the relative magnitude of denitrification activity may be regulated, among others, by a gradient of soil nitrate (low to high) between organic (peat bog, heathland, and acid grassland), forest (coniferous and deciduous), and grassland (improved and semi-improved) rural land use types. The denitrification potential (DP) of organic, forest and grassland soils, in two UK catchments was measured in the laboratory. Land use type significantly (p < 0.05) influenced the DP, which ranged between 0.02 and 63.3 mg N m(-2) h(-1). The averaged DP of organic and forest soils (1.08 mg N m(-2) h(-1)) was 3 and 10 times less than the DP of semi-improved (4.06 mg N m(-2) h(-1)) and improved (12.09 mg N m(-2) h(-1)) grassland soils, respectively; and among others, nitrate correlated positively (p < 0.05) with the DP. The results indicated that the difference in soil nitrate concentration between organic (naturally low in nitrate availability) and grassland soils (nitrate enriched due to land management) partially regulated the extent of DP. In the absence of N fertilisation, except for the atmospheric N deposition, the relatively low net nitrification potential (as a source of nitrate for denitrifiers) of organic and forest soils alone seem to have resulted in lower denitrifier's activity compared to grassland soils. Moreover, the interactions between soil organic carbon, pH, bulk density, water filled pore space, and texture, as these are influenced by the relative degree of land management, exerted additional controls on the DP. The results suggest that land management can have significant effects on denitrification, and thus needs to be considered when modelling and/or predicting the response of denitrification to land use change.