LUMBANTOBING, R. .; HIDAYAT, B.; LUBIS, A. . The Effect of Cow Manure and Cow Dung Biochar Application on P Available and Growth of Corn Plants in Ultisol. Jurnal Online Pertanian Tropik, [S. l.], v. 7, n. 3, p. 335–344, 2020. DOI: 10.32734/jopt.v7i3.6328. Disponível em: https://idjpcr.usu.ac.id/jpt/article/view/6328. Acesso em: 4 aug. 2025.