“Quality of Soil and Yield of Food Crops in Ultisols Due to Application of Manure and Source of Phosphate Fertilizer”. JOURNAL OF TROPICAL SOILS 17, no. 1 (May 28, 2019): 45–52. Accessed January 7, 2026. https://journal.unila.ac.id/index.php/tropicalsoil/article/view/318.