EGU2020-3890
https://doi.org/10.5194/egusphere-egu2020-3890
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Interactions between liming and availability of C and P regulate nitrogen transformations and denitrifying potential in an acidic arable soil

Zhi Liang, Diego Abalos, and Lars Elsgaard
Zhi Liang et al.
  • Aarhus University, Department of Agroecology, Denmark (zhi.liang@agro.au.dk)

Liming to increase pH of acidic soils is a common agricultural practice to optimize crop yields, which also modulates greenhouse gas emissions from soils. In particular, soil pH has been identified as a primary regulator of denitrification pathways with enhanced ratio of nitrous oxide (N2O) to dinitrogen (N2) emissions (i.e., enhanced N2O/N2 ratio) at lower soil pH. Therefore liming could represent a potential management option to mitigate soil N2O emissions. However, changes in soil pH have pervasive effects on general microbial activity and on soil properties, including transformations of carbon (C) and bioavailability of phosphorus (P), with a feedback on microbial processes. Thus, the eventual net effects of liming on microbially derived N2O emissions may be complex. The aim of this study was to discern the interaction between liming (soil pH), and availability of C and P in regulating N2O emissions from acidic fertilized agroecosystems. Using coarse sandy soils from a long-term liming field experiment, N2O/N2 ratios from denitrifying enzyme activity was shown to be strongly affected by liming, i.e., with gradually decreasing ratios at increasing soil pH. Although liming acidic soil (pH, 3.6) to almost neutral (pH, 6.4) favored the reduction of N2O to N2, it also enhanced the overall denitrification rate, which eventually resulted in the highest N2O emission from moderately limed treatments (pH, 4.7). Interactions between P availability and denitrification (and N2O emission) occurred, where P addition generally increased cumulative N2O emissions with strongest effect at the moderately limed soil. Mechanistic hypotheses for this effect are discussed. Overall, our results suggest that a critical liming rate should be pursued which may lead to substantial mitigation of N2O emissions from acidic arable soil.

How to cite: Liang, Z., Abalos, D., and Elsgaard, L.: Interactions between liming and availability of C and P regulate nitrogen transformations and denitrifying potential in an acidic arable soil, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3890, https://doi.org/10.5194/egusphere-egu2020-3890, 2020