Biology Centre of the ASCR, v.v.i. - Institute of Soil Biology, and University of South Bohemia - Faculty of Science, Na Sádkách 7, 370 05, České Budějovice, Czech Republic.
Folia Microbiol (Praha). 2011 May;56(3):230-5. doi: 10.1007/s12223-011-0045-x. Epub 2011 Jun 28.
The effects of pH on denitrifying enzyme activity (DEA) and on the ratio of the denitrification products, N(2)O and N(2), were determined in three pasture soils differing in cattle impact. The linkage between intrinsic differences in the denitrifying communities and pH effects on relative N(2)O production was also assessed. Soil pH values were adjusted just before DEA determination to obtain soil slurries with a range of pH values. The intrinsic differences in the denitrifier communities were assessed by measuring the kinetic constants of NO(3)(-) and N(2)O reductions. DEA for all three soils was highest at pH 8.4, regardless of native soil pH. Because DEA has typically been measured at native soil pH, our results suggest that DEA might have been underestimated in many previous studies. Further, relative N(2)O production at different pH values did not differ among the soils, even though the denitrifier communities differed in their intrinsic capability to reduce NO(3)(-) all the way to N(2), suggesting that the ratio of denitrification products (N(2)O and N(2)) is pH-specific rather than soil-specific. This suggests that manipulations of soil pH will alter N(2)O fluxes from agricultural soils.
本研究旨在探讨 pH 值对反硝化酶活性（DEA）和反硝化产物 N2O 和 N2 比例的影响，并评估反硝化群落的内在差异与 pH 值对相对 N2O 生成的影响之间的联系。在进行 DEA 测定之前，将土壤 pH 值调整至一定范围，以获得具有不同 pH 值的土壤悬浮液。通过测量 NO3-和 N2O 还原的动力学常数来评估反硝化菌群落的内在差异。所有三种土壤的 DEA 在 pH 值为 8.4 时最高，而与原生土壤 pH 值无关。由于 DEA 通常在原生土壤 pH 值下进行测量，因此我们的结果表明，在许多先前的研究中，DEA 可能被低估了。此外，尽管反硝化菌群落内在的将 NO3-还原为 N2 的能力存在差异，但不同 pH 值下的相对 N2O 生成没有差异，这表明反硝化产物（N2O 和 N2）的比例是 pH 特异性的，而不是土壤特异性的。这表明土壤 pH 值的调控将改变农业土壤中的 N2O 通量。
