Afriyani, A., Martinus, A. and Fratiwi, I. 2025. Utilization of coal burning waste fly ash as a soil improving material in red yellow podsolic soil. Jurnal Lahan Suboptimal : Journal of Suboptimal Lands. 14, 2 (Oct. 2025), 210–215. DOI:https://doi.org/10.36706/jlso.14.2.2025.727.