Amirrullah, J., Hutapea, Y., Ratmini, N. and Prabowo, A. 2020. Farmer Mentoring in Determining Fertilization Dosage of Corn Plants (Zea Mays L.) Using Soil Test Equipment. Jurnal Lahan Suboptimal : Journal of Suboptimal Lands. 9, 1 (Apr. 2020), 102–108. DOI:https://doi.org/10.33230/JLSO.9.1.2020.437.