A review of agronomic and environmental properties of inorganic compounds in biochars

The inorganic fractions of biochar are influenced by feedstock and pyrolysis conditions. They act as plant nu-trients but can also be harmful to the environment. Pyrolysis alters the content and availability of nutrients, including nitrogen, phosphorus, and potassium. Biochars contain trace elements, such as calcium, magnesium, sulfur, and silicon as well as heavy metals. We consider the sources of heavy metals in biochar and their bioavailability, focusing on ensuring agricultural application safety. Biochar-derived nanoparticles can transport inorganic compounds, posing environmental threats. Balancing positive contributions while minimizing the negative impacts of inorganic fractions is essential for optimizing agronomic benefits with biochar.