DA-Soils Laboratory, San Felipe, Ilagan City, Isabela, Philippines, Josephine, D., Margaret, C. A., Ernesto, D. G., Fevie, R. A. Fertility assessment and mapping of rice areas under the Magat River Integrated Irrigation System in Isabela, Philippines. Int. J. Agric. Tech. [internet]. 2015 Feb. 20 [cited 2025 Aug. 7];11(2):581-94. available from: https://li04.tci-thaijo.org/index.php/IJAT/article/view/6321