Barus, J. “Utilization of Crops Residues As Compost and Biochar for Improving Soil Physical Properties and Upland Rice Productivity”. Journal of Degraded and Mining Lands Management 3, no. 4 (July 1, 2016): 631–637. Accessed April 28, 2025. https://jdmlm.ub.ac.id/index.php/jdmlm/article/view/198.