Biochar, a carbon-rich material produced from the pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More of biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More, has become increasingly significant in enhancing soil properties and sequestering carbon. Accurate quantification of biochar in soils is crucial for evaluating its long-term carbon storage potential. This review, published in CATENA, discusses various methods for biochar quantification, their limitations, and future prospects.

Biochar enhances soil fertility and carbon sequestration due to its high stability and porosityPorosity of biochar is a key factor in its effectiveness as a soil amendment and its ability to retain water and nutrients. Biochar’s porosity is influenced by feedstock type and pyrolysis temperature, and it plays a crucial role in microbial activity and overall soil health. Biochar More. Its stability stems from its resistance to microbial degradation and its complex aromatic structures. However, quantifying biochar in soil is challenging due to the limitations of existing methods, most of which are adapted from black carbon (BC) analysis techniques.

The review categorizes biochar quantification methods into four main types:

1. Thermal Oxidation Methods: These rely on the thermal stability of biochar to differentiate it from other soil organic matter. However, these methods can result in the loss of biochar during high-temperature treatments.
2. Chemical Oxidation Methods: These methods use chemicals to oxidize non-biochar organic matter, leaving biochar intact. While effective, they can be labor-intensive and time-consuming.
3. Benzene Poly-Carboxylic Acids (BPCAs) Molecular Marker Methods: This approach identifies biochar by detecting specific aromatic compounds. It is accurate but requires sophisticated equipment and expertise.
4. Optical Methods: These techniques use spectroscopy to identify biochar based on its unique spectral characteristics. While promising, they need further refinement to improve accuracy and reliability.

The review highlights several challenges in biochar quantification, including interference from soil minerals and organic matter, and the varying stability of biochar components. Future research should focus on developing standardized, accurate, and efficient methods tailored specifically for biochar.

Accurate biochar quantification is essential for understanding its role in carbon sequestration and soil health. This review provides a comprehensive overview of current methods, their advantages, and limitations, offering a valuable resource for researchers in the field.