Journal article

Publication year: 2022

Journal: European Journal of Soil Science

Volume number: 73

Issue number: 6

ISSN: 1351-0754

eISSN: 1365-2389

DOI Link: https://doi.org/10.1111/ejss.13327

Publisher: Wiley

Abstract: 

Two methodological approaches are commonly used to investigate heterotrophic nitrification (Nit_h) in soil: process inhibitions and ¹⁵N tracing. Although many studies have reported Nit_h based on ¹⁵N tracing approaches, estimates via specific inhibitor are less common. Therefore, we conducted a meta-analysis to illustrate the similarities and differences of the results of soil Nit_h between the two approaches. We observed that the average result of gross Nit_h rate was significantly lower with the ¹⁵N tracing approach (1.32 mg N kg⁻¹ day⁻¹) than with the inhibitor approach (3.54 mg N kg⁻¹ day⁻¹) (p < 0.01). Possible explanations include incomplete inhibition of autotrophic nitrification (Nit_a) due to the adsorption of inhibitors on soil aggregates and the fact that the estimation of Nit_h via ¹⁵N tracing quantifies only the Nit_h fraction related to organic N oxidation. The results of linear-mixed models indicated that soil C:N ratio had a significantly positive effect on the difference of Nit_h estimated via ¹⁵N tracing and inhibitor approach, which was also supported by the paired data between natural and C- and N- manipulated soil. The average contribution of Nit_h to total nitrification, estimated by the ratio of Nit_h:(Nit_h + Nit_a) or the capacity of NO₂⁻/NO₃⁻ production when Nit_a was inhibited, in the two approaches were not significantly different (34% vs. 33%). While, soil C:N ratio also caused a significantly positive effect on the contribution of Nit_h to soil total nitrification (p < 0.05). In conclusion, the result of the relative contribution of Nit_h is less affected by approach than the result of gross Nit_h rate. In addition, soil C and N substrate availability is likely to be a critical factor affecting the estimation of soil Nit_h by the two approaches.

Harvard Citation style: Zhang, Y., Cai, Z., Zhang, J. and Müller, C. (2022) Quantification of soil heterotrophic nitrification in 15N tracing and specific inhibitor approaches, European Journal of Soil Science, 73(6), Article e13327. https://doi.org/10.1111/ejss.13327

APA Citation style: Zhang, Y., Cai, Z., Zhang, J., & Müller, C. (2022). Quantification of soil heterotrophic nitrification in 15N tracing and specific inhibitor approaches. European Journal of Soil Science. 73(6), Article e13327. https://doi.org/10.1111/ejss.13327