Iskandar, Iskandar, and Indah Irwanti. “Use of Volcanic Sand As a Natural Fertilizer: Increasing Release of NutrientsUse of Volcanic Sand As a Natural Fertilizer: Increasing Release of Nutrients”. Jurnal Ilmu Tanah dan Lingkungan 5, no. 1 (April 1, 2003): 23-28. Accessed November 22, 2024. https://journal.ipb.ac.id/index.php/jtanah/article/view/2332.