Amirrullah, Johanes, Yanter Hutapea, NPS Ratmini, and Agung Prabowo. “Farmer Mentoring in Determining Fertilization Dosage of Corn Plants (Zea Mays L.) Using Soil Test Equipment”. Jurnal Lahan Suboptimal : Journal of Suboptimal Lands 9, no. 1 (April 1, 2020): 102–108. Accessed April 26, 2024. https://jlsuboptimal.unsri.ac.id/index.php/jlso/article/view/437.