“Soil Test Kit: An Extension Tool of Central Bicol State University of Agriculture (CBSUA), Pili, Camarines Sur, Philippines”, JMDS, vol. 3, pp. 50–61, Dec. 2014, Accessed: Sep. 10, 2026. [Online]. Available: https://jmds.upou.edu.ph/index.php/journal/article/view/6