Biochar Based Soil Amendment Formulation for Improvement Upland Acidic Soil in East Lampung: Soil Properties and Maize (Zea Mays) Yield. j Trop. Soils [Internet]. 2019 Jan. 2 [cited 2025 Nov. 3];24(1):33-41. Available from: https://journal.unila.ac.id/index.php/tropicalsoil/article/view/339