Biochar Application: A Sustainable Approach for Managing Stem Rot Disease in Peanut Caused by Sclerotium rolfsii Sacc.

Soilborne pathogens are often difficult to manage due to a wide host-range and long-term survival of pathogens. Inorganic and organic soil amendments are considered as one of the key management strategies. Biochar, produced through biomass pyrolysis under oxygen-limited conditions, has gained attention for enhancing soil structure, sequestering carbon, improving water retention, and boosting fertility. Beyond its role in soil enhancement, biochar shows potential in managing soilborne diseases. This study explores the multifaceted impact of biochar in managing stem rot disease in peanut, as well as its influence on soil properties and microbial communities. The effects of different biochar concentrations such as 0% (no biochar + S. rolfsii), 1%, 3% and 5% on Sclerotium rolfsii-induced stem rot were thoroughly assessed. Under laboratory conditions, biochar did not exhibit inhibitory effects on S. rolfsii at any concentration; however, it significantly reduced sclerotia formation, indicating a concentrationdependent suppression of pathogen resting structures. Moreover, biochar treatments effectively delayed disease onset and slowed disease progression in peanut plants, with notable variation observed among genotypes and biochar concentrations. Interactions involving genotypes ICGV 171002 and ICGV 181035 with BC2 + Sr (3% biochar + S. rolfsii) and BC3 + Sr (5% biochar + S. rolfsii) demonstrated superior disease suppression under controlled conditions. Field evaluations further validated these findings, revealing genotype-specific responses to biochar applications. However, no significant difference was observed between BC2 + Sr (3%) and BC3 + Sr (5%) in their ability to manage stem rot disease compared to controls. In addition to disease management, biochar improved soil fertility by increasing nitrogen, phosphorus, and potassium levels while enhancing soil organic matter, electrical conductivity and pH. These findings highlight biochar’s potential as a sustainable soil amendment, contributing to disease suppression and soil health improvement. Further research is needed to optimize biochar application strategies across diverse agricultural settings.