Effect of different types of biochar on soil properties and functional microbial communities in rhizosphere and bulk soils and their relationship with CH4 and N2O emissions

Jian-Qing Qi; Hai-Yan Yuan; Qi-Lu Zhuang; Eric-Fru Zama; Xiao-Fei Tian; Bao-Xian Tao; Bao-Hua Zhang

doi:10.3389/fmicb.2023.1292959

Effect of different types of biochar on soil properties and functional microbial communities in rhizosphere and bulk soils and their relationship with CH₄ and N₂O emissions

Front Microbiol. 2023 Nov 2:14:1292959. doi: 10.3389/fmicb.2023.1292959. eCollection 2023.

Authors

Jian-Qing Qi¹, Hai-Yan Yuan¹, Qi-Lu Zhuang¹, Eric-Fru Zama², Xiao-Fei Tian¹, Bao-Xian Tao¹, Bao-Hua Zhang¹

Affiliations

¹ School of Geography and Environment, Liaocheng University, Liaocheng, China.
² Department of Agricultural and Environmental Engineering, College of Technology, University of Bamenda, Bambili, Cameroon.

Abstract

Biochar as an agricultural soil amendment plays vital roles in mediating methane (CH₄) and nitrous oxide (N₂O) emissions in soils. The link between different types of biochar, bulk soil, and rhizosphere microbial communities in relation to CH₄ and N₂O emissions is being investigated in this study. The rice pot experiment was conducted using biochar at two temperatures (300°C and 500°C) in combination with three biochar levels (0, 2, 10% w/w). Soil properties and the abundance of genes associated with CH₄ and N₂O emissions from both rhizosphere and bulk soils were investigated. The study also aimed to examine the structure of microbial communities (pmoA, nosZ) in rhizosphere and bulk soils whereas CH₄ and N₂O emissions were monitored while growing rice. Results showed that biochar at 300°C and 10% incorporation significantly increased the CH₄ emissions by up to 59% rise compared to the control group. Random Forest analysis revealed that the ratio of mcrA/pmoA along with the abundance of mcrA from both rhizosphere and bulk soils, the abundance of AOA, TN, DOC, and the community composition of pmoA-harboring microorganisms from both bulk and rhizosphere soils were important predictors of CH₄ emissions. Therefore, the ratio of mcrA/pmoA in rhizosphere soil and the abundance of AOA in bulk soil were the main factors influencing CH₄ emissions. Variation Partitioning Analysis (VPA) results indicated that the effects of these factors on bulk soil were 9% of CH₄ emissions variations in different treatments, which contributed more than rhizosphere soils' factors. Moreover, random forest analysis results indicated that the abundance of AOB in bulk soil was the most important predictor influencing N₂O emissions. The VPA result revealed that the factors in rhizosphere soil could explain more than 28% of the variations in N₂O emissions. Our study highlights that rhizosphere soil has a more significant effect than bulk soil on N₂O production. Our findings further the understanding of the link between bulk and rhizosphere attributes, and their impact on CH₄ and N₂O emissions in paddy soils. In summary, we recommend the application of biochar at 500°C and 2% incorporation rate for agricultural production in the area.

Keywords: CH4; N2O; biochar; bulk; nosZ; pmoA; rhizosphere.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was funded by the National Natural Science Foundation of China (42007219), Natural Science Foundation of Shandong Province, China (ZR2020MD004), Students’ innovation and entrepreneurship training program of Liaocheng University (S202210447046), and Doctoral Scientific Research Foundation of Liaocheng University (318052034).