Agricultural soils are a major source of greenhouse gases. Biochar is a soil improver and, when applied to the soil, sequesters carbon. However, a different combination of soil and climatic conditions and biochar leads to different research results. In this research, the effects of 1 kg/m2 and 3 kg/m2 biochar application to clay soils on the CO2 flow in field experiments along two cropping seasons in the Russian Far East were investigated. Data showed that biochar significantly reduces the cumulative flow of soil CO2, compared with untreated field plots. In 2018, the greatest reduction in soil CO2 emissions (28.2%) with 3 kg/m2 of biochar was obtained, while in 2019, the greatest decrease in the cumulative CO2 flow at the application dose of 1 kg/m2 (57.7%) was recorded. A correlation between a decrease in the value of the cumulative CO2 flux and an increase in the biomass grown in the studied areas of agricultural crops during the season of 2018 was found.

The study investigates the effect of biochar on nitrous oxide emission in Endoargic Anthrosols in the southern territory of the Russian Far East. Biochar (bio-charcoal) was applied in the amounts of 1 kg/m2 and 3 kg/m2 in combination with organic and mineral fertilizers to drained and drain-free fields during the vegetation season, and the five-gas analyzer G2508 (Picarro) was used. Cumulative flows of N2O were estimated. The analysis revealed that biochar reduces the emissions and the cumulative flow of nitrous oxide. The higher the dose of biochar, the lower the emission and cumulative flows of nitrous oxide, regardless of a drainage system. Biochar (1 kg/m2) reduced the cumulative N2O flow from the soil by 52.2% throughout the experiment conducted, while a dose of 3 kg/m2 allowed for 97.8% reduction. The study found that organic and mineral fertilizers can be effectively used in combination with biochar, as N2O emission from the soil with mineral fertilizers is significantly higher than from the soil with organic fertilizers. Biochar (1 kg/m2) combined with organic fertilizers reduces N2O emission by 53.7%, while a dose of 3 kg/m2 can reduce emissions by 88.9%. Biochar (1 kg/m2) combined with mineral fertilizers reduced the flow of N2O by 17.5%, while a 3 kg/m2 dose of biochar used with mineral fertilizers reduced the emission by 85.3%.

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