A significant study by Xinru Li and colleagues explores how integrating biochar with different tillage practices can solve the dual challenges of soil degradation and rising greenhouse gas (GHG) emissions. Conducted in the western Songnen Plain of Northeast China—a critical “black soil” region—the research evaluated three tillage methods: rotary tillage with stubble breaking (RS), rotary tillage alone (RT), and stubble breaking alone (ST). By applying varying biochar rates, the study aimed to restore soil fertility while supporting China’s “dual carbon” goals for environmental sustainability.

The study found that biochar acts as a stabilizing force for soil physical properties. Under all tillage methods, biochar application significantly increased moisture content; for instance, stubble breaking (ST) combined with biochar maintained higher moisture than other methods because it causes less soil disturbance and reduces evaporation. Additionally, the black color of biochar enhances heat absorption, raising soil temperatures by up to 17.7% and reducing thermal variability, which is vital for maintaining stable growing conditions in temperate climates.

Nutrient preservation is another major benefit of this integrated approach. The researchers observed that biochar’s porous structure effectively adsorbs nitrogen, facilitating nitrification while reducing leachingLeaching is the process where nutrients are dissolved and carried away from the soil by water. This can lead to nutrient depletion and environmental pollution. Biochar can help reduce leaching by improving nutrient retention in the soil.   More losses. The highest nitrogen contents—including total nitrogen, nitrate nitrogen, and ammonium nitrogen—were recorded at the maximum biochar application rate of 3 t/hm². Stubble retention methods (ST) were particularly effective here, as they reduced soil erosion and mineralization compared to more aggressive rotary tillage.

The environmental impact of these practices is perhaps the most critical finding. While biochar can slightly increase CO_2​ emissions due to enhanced microbial respiration, it serves as a robust inhibitor for more potent greenhouse gases. Specifically, the application of 3 t/hm² of biochar reduced nitrous oxide emissions significantly—by as much as 36.42% in ST plots—and promoted the soil’s ability to absorb methane. These results indicate that biochar interferes with the denitrification process, effectively converting harmful byproducts into harmless nitrogen gas.

To determine the best overall strategy, the study employed a “TOPSIS” comprehensive evaluation method, which weighed soil health indicators against emission rates. The analysis concluded that the RS3 scheme—combining 3 t/hm² biochar with rotary tillage and stubble removal—achieved the highest score for optimizing both soil resilience and greenhouse gas mitigation. This research provides a practical framework for farmers to transition toward more sustainable, high-yield agriculture while actively fighting global climate change.

Source: Li, X., Xiao, Z., Meng, F., Li, G., Li, T., Zheng, E., Li, M., Wang, J., & Fan, Y. (2025). Effects of tillage practices and biochar application rates on soil properties and greenhouse gas emissions in farmland. SSRN.