For feasibility of carbon sequestration as well as in the mitigation of greenhouse gases for application of biochar pellet, this experiment was conducted, focusing on the adsorption characteristics of NH₄-N on biochar pellet mixed with different ratios of pig manure compost. For NH₄-N adsorption on biochar pellets, the loading amount of biochar pellet was 211.5 mg in 50 mL of aqueous solution, and the adsorption fitted very well with Langmuir isotherm. The maximum adsorption and removal rates were 2.94 mg g⁻¹ and 92.2%, respectively, in the pellet that contained 90% of biochar. It was also observed, by kinetic models, that NH₄-N was adsorbed fast on biochar pellet with a combination ratio of 9:1 of biochar pellet/pig manure. It was further observed that the higher the amount of biochar contained in the biochar pellet, the greater the adsorption of NH₄-N. For the plant response observed for lettuce, it was shown that the leaf biomass in plots treated with a 9:1 biochar/pig manure compost increased by approximately 13% compared with the leaf biomass in plots treated with the compost alone. The leaf biomass of the other treatments was higher than that of the control. This implies that the application of biochar pellets, regardless of the biochar contents, might be useful for soil carbon sequestration and greenhouse gas mitigation for agricultural practices.

For the recycling of biomass conversion materials, this experiment was conducted to investigate plant nutrient releasing characteristics, and to determine an optimum blended ratio of biochar for producing a biochar pellet based on a column leaching study. The treatments consisted of only pig manure compost (PMC) as a control, pig manure compost pellets (PMCP), and biochar pellets (BCP) blended with biochar and pig manure compost with the following ratios: 9:1, 8:2, 4:6, and 2:8. Results showed that the accumulated amount of ammonium nitrogen (NH₄-N) was in order of PMC > PMCP > BCP (2:8) > BCP (4:6) > BCP (8:2) > BCP (9:1) ratios. The highest accumulated amounts of phosphate phosphorus (PO₄-P) and potassium (K) were 1953 and 1917 mg L⁻¹ in the PMC and PMCP, but the lowest in the BCP (9:1) were 223 and 1078 mg L⁻¹, respectively. It was shown that the highest accumulated amount of silicon dioxide (SiO₂) was 2329 mg L⁻¹ in the BCP (8:2), but the lowest in the PMC was 985 mg L⁻¹. The estimations for accumulated NH₄-N, PO₄-P, K, and SiO₂ releasing amounts in all the treatments were significantly fitted with a modified Hyperbola model. The optimum mixing rate was estimated to be BCP (2:8). Therefore, biochar pellets might be useful in obtaining basic information on slow-release fertilizer for sustainable agriculture.

Only a few have evaluated the mitigation of greenhouse emissions and profit analysis along with soil carbon sequestration for corn cultivation. This experiment was conducted to evaluate the carbon sequestration and mitigation of greenhouse gas emissions as well as their profit analysis with different composts mixed with biochar during corn cultivation. This experimental data provided the second year of corn cultivation. The soil type used was clay loam. The application amounts of synthetic fertilizer and biochar were 220–30–155 kg ha⁻¹ (N–P–K) as the recommended amount after soil analysis and 2600 kg ha⁻¹ based on 1.3% of soil bulk density. For the biannual experimental results, it appeared that carbon sequestration in cow manure cooperated with biochar was highest at 2.3 tons ha⁻¹ and recovered from 67.3 to 78.5% with biochar application. Furthermore, mitigation of CO₂-eq. emission as greenhouse gases was estimated to be at 7.3–8.4 MT ha⁻¹, and its profit was evaluated from $7.2 to 8.4 as lowest, from $57.2 to 66.6 as medium and from $139.7 to 162.7 as highest per hectare regardless of organic compost types used. For agricultural practice in Korea, it is evaluated that the market price of CO₂ in corn field cooperated with 2600 kg ha⁻¹ of biochar application ranged from $57.2 to 162.7 per hectare in Korean Climate Exchange. For corn biomass, the treatment with biochar application did not significantly decrease compared with the only organic compost application. Based on these experimental results, it might be applied for carbon trading with clean development mechanism for agricultural practices.