Slow-release property and soil remediation mechanism of biochar-based fertilizers

Biochar-based fertilizers refer to biochar-containing organic, inorganic fertilizer, or both. Biochar-based fertilizers have prospects in agricultural production and environmental protection fields because of their nutrient slow-release and environmental-friendly properties. The slow-release property of biochar-based fertilizers is attributed to its combination modes with N, P, and K nutrients, including electrostatic attraction, complexity, mineralization and so on. The raw materials, production process, and ratio of biochar to fertilizer strongly influence the slow-release property of biochar-based fertilizers. Biochar-based fertilizers could improve soil physical and chemical properties, regulate soil microbial activities, improve efficiency of plant nutrients utilization, and reduce loss of nutrients in soil. The researches needed to promote the efficient use of biochar-based fertilizers include: assessment of the long-term effect and aging of biochar after its incorporation into soil; risk assessment of biochar to microbial structure and diversity; monitoring the sustainability and cumulative effect of biochar-based fertilizer in soil remediation; and setting standards for the application of biochar-based fertilizer.