“Effect of Coated Urea With Humic-Calcium on Transformation of Nitrogen in Coastal Sandy Soil: A Soil Column Method”. JOURNAL OF TROPICAL SOILS 15, no. 1 (April 9, 2018): 11–18. Accessed January 3, 2026. https://journal.unila.ac.id/index.php/tropicalsoil/article/view/22.