Biochar as a carbon‐rich coproduct of pyrolyzing biomass, its amendment has been advocated as a potential strategy to soil carbon (C) sequestration. Updated data derived from 50 papers with 395 paired observations were reviewed using meta‐analysis procedures to examine responses of soil carbon dioxide (CO₂) fluxes, soil organic C (SOC), and soil microbial biomass C (MBC) contents to biochar amendment. When averaged across all studies, biochar amendment had no significant effect on soil CO₂ fluxes, but it significantly enhanced SOC content by 40% and MBC content by 18%. A positive response of soil CO₂ fluxes to biochar amendment was found in rice paddies, laboratory incubation studies, soils without vegetation, and unfertilized soils. Biochar amendment significantly increased soil MBC content in field studies, N‐fertilized soils, and soils with vegetation. Enhancement of SOC content following biochar amendment was the greatest in rice paddies among different land‐use types. Responses of soil CO₂ fluxes and MBC to biochar amendment varied with soil texture and pH. The use of biochar in combination with synthetic N fertilizer and waste compost fertilizer led to the greatest increases in soil CO₂ fluxes and MBC content, respectively. Both soil CO₂ fluxes and MBC responses to biochar amendment decreased with biochar application rate, pyrolysis temperature, or C/N ratio of biochar, while each increased SOC content enhancement. Among different biochar feedstock sources, positive responses of soil CO₂ fluxes and MBC were the highest for manure and crop residue feedstock sources, respectively. Soil CO₂ flux responses to biochar amendment decreased with pH of biochar, while biochars with pH of 8.1–9.0 had the greatest enhancement of SOC and MBC contents. Therefore, soil properties, land‐use type, agricultural practice, and biochar characteristics should be taken into account to assess the practical potential of biochar for mitigating climate change.

Misuse and overuse of antibiotics have contributed to the rise of antimicrobial resistance as one of the top public health threats. Antibiotics and antibiotic resistance genes (ARGs) are prevalent in agricultural soils due to the widespread application of livestock and organic wastes. However, information about the occurrence, distribution, and risk of antibiotics and ARGs in agricultural soils is lacking for many scenarios. In this study, based on 2225 observations from 135 independent studies, we summarized the concentration or abundance of antibiotics or ARGs under different fertilizer sources and land-use patterns, analyzed the contributions of key environmental factors to the occurrence of antibiotics and ARGs in agricultural soils, and highlighted the potential ecological risk of typical antibiotics and the relationship between ARGs and mobile genetic elements (MGEs). Our results showed that cattle manure, chicken manure, swine manure, and sewage sludge were the primary pollution sources of antibiotics and ARGs in agricultural soils, and sulfonamides, tetracyclines, fluoroquinolones, and their corresponding ARGs were the main pollution types. Land-use type, soil, and climatic factors affected antibiotics concentration and ARG abundances. MGEs play a vital role in promoting the dissemination of ARGs, especially the sul1 gene is closely related to intI1. In conclusion, our findings and future research exploring these topics will contribute to better management of antibiotic and ARG contamination in agricultural soils and their risk to human health. Graphical Abstract