The legacy effect of biochar application on soil nitrous oxide emissions. Issue 4 (22nd December 2022)

• Record Type: Journal Article
• Authors: Guo, Shumin; Wu, Jie; Han, Zhaoqiang; Li, Zhutao; Xu, Pinshang; Liu, Shuwei; Wang, Jinyang; Zou, Jianwen
• Is Part Of: Global change biology. Volume 15:Issue 4(2023)
• Page Start: 478
• Page End: 493
• Publication Date: 2022-12-22
• Subjects: acidic soil -- biochar -- climate change -- fertilizer -- functional gene -- mitigation option; Biomass energy -- Periodicals; Biomass energy -- Environmental aspects -- Periodicals; Energy crops -- Periodicals; 662.88
• DOI: 10.1111/gcbb.13022
• Languages: English
• ISSNs: 1757-1693

Abstract

Abstract: Existing studies suggest that biochar application can reduce soil nitrous oxide (N2 O) emissions, mainly based on short‐term results. However, it remains unclear what the effects (i.e., legacy effects) and underlying mechanisms are on N2 O emissions after many years of a single application of biochar. Here, we collected intact soil columns from plots without and with biochar application in a subtropical tea plantation 7 years ago for an incubation experiment. We used the N2 O isotopocule analysis combined with ammonia oxidizer‐specific inhibitors and molecular biology approaches to investigate how the legacy effect of biochar affected soil N2 O emissions. Results showed that the soil in the presence of biochar had lower N2 O emissions than the control albeit statistically insignificant. The legacy effect of biochar in decreasing N2 O emissions may be attributed to the reduced effectiveness of the soil substrate, nitrification and denitrification activities, and the promotion of the further reduction of N2 O. The legacy effect of biochar reduced the relative contribution of nitrifier denitrification/bacterial denitrification, nitrification‐related N2 O production, and the relative abundance of several microorganisms involved in the nitrogen cycle. Our global meta‐analysis also showed that the reduction of N2 O by biochar increased with increasing application rate but diminished and possibly even reversed with increasing experimental time. In conclusion, our findings suggest that the abatement capacity of biochar on soil N2 O emissions may weaken over time after biochar application, but this remains under further investigation. Abstract : Although biochar has received great attention in mitigating non‐carbon dioxide greenhouse gases, we remain unknown what the legacy effects of biochar application are. We revealed lower nitrous oxide emissions in acidic tea plantation soils after 7 years of biochar application than in control, which may be mainly related to changes in substrate effectiveness and the abundance, activity, and composition of functional microorganisms associated with the nitrogen cycle. However, our meta‐analysis showed that the mitigation effect of a single biochar application on nitrous oxide emissions diminished with time. Thus, our work also underlines that more long‐term experimental studies from diverse climatic and soil conditions are urgently needed to determine the legacy effects of biochar.