Kasno, A, Abdul Rachim, Iskandar Iskandar, and AdiningsihJ. Sri. “Relationship Between K/Ca Ratios in the Soil Solution With the Dynamic of K in Ultisol and Vertisol of Upland Area”. Jurnal Ilmu Tanah dan Lingkungan 6, no. 1 (April 1, 2004): 7-13. Accessed May 2, 2024. https://journal.ipb.ac.id/index.php/jtanah/article/view/2336.