Jayadi, Muhammad, Kadar Wahid, Risma Neswati, and Andri Andriansyah. 2022. “Improvement of Post-Nickel Mining Soil Fertility With Biochar and Calcite”. Journal of Degraded and Mining Lands Management 10 (1). Malang, Indonesia:3803-8. https://doi.org/10.15243/jdmlm.2022.101.3803.