Soelaeman, Yoyo, and Umi Haryati. 2019. “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 (1):45-52. https://doi.org/10.5400/jts.2012.v17i1.45-52.