Question Besides fuel combustion, coal processing, etc., agricultural soils are also a major source of greenhouse gas CO2. How to reduce agricultural greenhouse gas (GHG) emissions through anthropogenic regulatory factors has received widespread attention. A high-quality soil amendment to improve soil habitat, biochar, has emerged.Materials and methods In this study, a novel and efficient functional biochar was prepared by potassium hydroxide (KOH) modification. Virgin biochar (450BC) and modified biochar (450KBC) were grown in two ratios (w/w) for 61 days for soil improvement, and a total of five treatments were set up: CK (0%), 2%450BC (20 g 450BCkg(-1) soil(-1)), 2%450KBC (20 g 450KBCkg(-1) soil(-1)), 4%450BC (40 g 450BCkg(-1) soil(-1)), 4%450KBC (40 g 450KBCkg(-1) soil(-1)).Results and discussion The biochar caused an increase in soil pH, CEC, SOM content, and the concentration of soil NH4+-N and a decrease of the concentration of NO3–N. Bivariate correlation analysis revealed that CO2 emissions are negatively correlated with SOC, pH, and MBN and positively with CEC and MBC. The biochar inhibited the beta-glucosidase activity and kept the SOM degradation under control. The activity of beta-glucosidase was not significantly related to the amount of biochar applied, but the effect of the modified biochar was significantly multiplied compared with the virgin biochar, and the most significant reduction in beta-glucosidase activity was observed with 4%450 KBC (30%). The order of total CO2 emissions for 61 days of indoor incubation was 4%450KBC < 2%450KBC < 4%450BC < 2%450BC < CK.Conclusions The application of 450KBC is an appropriate agricultural management strategy that improves the soil biochemical environment while helping to suppress soil CO2 emissions.
