Indawan, Edyson, Sri Umi Lestari, and Nurita Thiasari. 2018. “Sweet Potato Response to Biochar Application on Sub-Optimal Dry Land”. Journal of Degraded and Mining Lands Management 5 (2). Malang, Indonesia:1133-39. https://doi.org/10.15243/jdmlm.2018.052.1133.