Journal Article

Comparison of Biochar- and Lime-Adjusted pH Changes in Nsub.2O Emissions and Associated Microbial Communities in a Tropical Tea Plantation Soil

Liu, Shuoran, Ruan, Yunze, Wang, Ziwei, Zhang, Zhijun, Wang, Qing

2023

Overview

The use of biochar and lime (CaO) is a common approach to mitigating soil acidification. However, little is known about how biochar and lime amendments impact N[sub.2]O emissions and potential microbial mechanisms. We conducted a 45-day microcosm incubation experiment to examine N[sub.2]O emission and associated functional guilds to biochar and lime amendment in an acidic tea plantation soil. Results show that lime and biochar treatments significantly reduced cumulative N[sub.2]O emissions by 49.69% and 63.01%, respectively, while significantly increasing cumulative CO[sub.2] emissions by 27.51% and 19.35%, respectively. Additionally, lime and biochar treatments significantly decreased the abundances of bacterial nirK, nirS, nosZ and fungal nirK genes, while increasing that of the ammonia-oxidizing bacteria (AOB) and the complete ammonia-oxidizing bacteria (comammox) amoA genes. The stimulated or inhibitory effects of biochar on functional genes abundances were higher than lime. The N[sub.2]O emission rate was positively linked with the abundance of the fungal nirK gene but was negatively correlated with AOB and comammox amoA genes abundances. The random forest and linear regression analysis revealed that fungal denitrifiers were the most important predictors of N[sub.2]O emissions. Lime and biochar amendments reduced the alpha diversity and altered the community composition of nirK-harboring fungal denitrifiers. Ascomycota was the dominant fungal denitrifiers belonging to the families Nectriaceae, Aspergillaceae, and Chaetomiaceae, and the relative abundances of genera Chaetomium, Penicillium and Fusarium were positively correlated with N[sub.2]O emissions. Overall, our findings suggest that biochar is more effective than lime in reducing N[sub.2]O emissions, and this is likely due to the powerful effects it has on community traits of nirK-harboring fungal denitrifiers.

• Publisher: MDPI AG
• Subject: Plantations / Tea industry