Field-applied biochar-based MgO and sepiolite composites possess CO2 capture potential and alter organic C mineralization and C-cycling bacterial structure in fertilized soils

Muhammed Mustapha Ibrahim; Liming Guo; Fengying Wu; Dongming Liu; Hongxue Zhang; Shuangquan Zou; Shihe Xing; Yanling Mao

doi:10.1016/j.scitotenv.2021.152495

Field-applied biochar-based MgO and sepiolite composites possess CO₂ capture potential and alter organic C mineralization and C-cycling bacterial structure in fertilized soils

Sci Total Environ. 2022 Mar 20:813:152495. doi: 10.1016/j.scitotenv.2021.152495. Epub 2021 Dec 27.

Authors

Muhammed Mustapha Ibrahim¹, Liming Guo², Fengying Wu², Dongming Liu², Hongxue Zhang², Shuangquan Zou², Shihe Xing², Yanling Mao³

Affiliations

¹ College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian Province, China; Key Research Laboratory of Soil Ecosystem Health and Regulation in Fujian Provincial University, Fuzhou 350002, Fujian Province, China; Department of Soil Science, Joseph Sarwuan Tarka University, P.M.B, 2373 Makurdi, Nigeria.
² College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian Province, China; Key Research Laboratory of Soil Ecosystem Health and Regulation in Fujian Provincial University, Fuzhou 350002, Fujian Province, China.
³ College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian Province, China; Key Research Laboratory of Soil Ecosystem Health and Regulation in Fujian Provincial University, Fuzhou 350002, Fujian Province, China; Fujian Colleges and Universities Engineering Research Institute of Conservation and Utilization of Natural Bioresources, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian Province, China. Electronic address: fafum@126.com.

PMID: 34968614
DOI: 10.1016/j.scitotenv.2021.152495

Abstract

Agricultural soils contribute a significant amount of anthropogenic CO₂ emission, a greenhouse gas of global environmental concern. Hence, discovering sustainable materials that can capture CO₂ in cultivated soils is paramount. Since the effect of biochar on C mineralization/retention in fertilized soils is unclear, we produced biochar-based MgO and sepiolite-nanocomposites with CO₂ capture potential. The field-scale impacts of the modified-biochars were evaluated on net C exchange rate (NCER) periodically for 3 months in fertilized plots. The effects of the modified-biochar on organic-C mineralization, the activities, and dynamics of C-cycling-related 16S rRNA which are unknown, were investigated. Results revealed an initial rapid and higher cumulative CO₂ emission from the sole fertilizer treatment (F). Unlike the biochar treatment (BF), the successful incorporation of MgO/Mg(OH)₂ nanoparticles into the matrix and surface of biochar, and the potential formation of MgCO₃ with soil CO₂, mitigated CO₂ emission, especially in the MgO-modified biochar (MgOBF), compared to the sepiolite-biochar treatment (SBF). Compared to F and BF, the higher C retention as MgCO₃ in the modified biochar treatments led to an increase in cellulase activity, stimulation of key C-cycling-related bacteria, and the expression of genes associated with starch, sucrose, amino sugar, nucleotide sugar, ascorbate, aldarate, cellulose, and chitin degradation, thus, increasing organic C mineralization. Among the modified-biochar treatments, higher C mineralization was recorded in SBF, resulting in increased cumulative CO₂ emission, despite its initial capture for up to 42 days. However, MgOBF was effective in capturing soil-derived CO₂, despite the increased C mineralization compared to biochar. The changes in soil moisture and temperature significantly regulated NCER. Also, the modified biochars positively influenced the distribution of C-cycling-related bacteria by improving soil pH and available nutrients. Among the modified biochars, the observed higher mitigation effect of MgOBF on NCER indicated that it could be preferably applied in agricultural soils.

Keywords: Biochar nanocomposites; C-cycling bacteria; Enzyme activity; MgO; Sepiolite; Soil respiration.

MeSH terms

Bacterial Structures
Carbon Dioxide*
Charcoal
Magnesium Oxide
Magnesium Silicates
RNA, Ribosomal, 16S
Soil*

Substances

Magnesium Silicates
RNA, Ribosomal, 16S
Soil
biochar
Carbon Dioxide
Charcoal
Magnesium Oxide
magnesium trisilicate