Meta-Analysis Study on the Role of Biochar on Soil Nitrogen Cycling

Abstract

Soil nitrogen cycling is intricately related to soil physicochemical properties, enzymatic activity, and microbial vitality. Biochar, containing various elements such as carbon, nitrogen, and phosphorus, possesses a porous structure with strong adsorption capabilities. This characteristic renders it useful for ameliorating acidic soils, influencing soil nitrogen cycling, and mitigating greenhouse gas emissions. To quantitatively analyze the diverse impacts of different biochar on soil nitrogen cycling and to highlight its implications for sustainable agriculture, this study collected 155 relevant articles and conducted a comprehensive meta-analysis. The results indicate that biochar can elevate the pH by 4.60% for acidic soils and significantly increase soil organic carbon content by 64.60%. Different feedstocks, such as Wooden Biochar (WB), Crop Husk (CH) Biochar, Crop Straw Biochar (CS), and Organic Waste Biochar (OW), exhibit distinct effects, with WB and OW showing the most significant increases in SOC. Pyrolysis temperature is also a critical factor, and biochar produced at medium and high temperatures enhances pH more effectively than low-temperature biochar. Additionally, biochar enhances the abundance of the nitrogen functional gene amoA-AOB by 25.58%, promoting ammonia oxidation, reducing ammonia (NH₃) emissions by 16.39%. Experimental setups also influence outcomes that biochar application in woods and incubation studies significantly reduced nitrous oxide (N₂O) emissions compared to pot and field experiments. The findings suggest that adding biochar to soil accelerates nitrogen cycling, thereby reducing greenhouse gas emissions. The results advocate biochar’s use in sustainable soil management practices.

Graphical Abstract