SARI, K.; SUPRIADI; SIREGAR, A. Z. .; SIBARANI, M. J. . Survey and Mapping of P Nutrient Status on Paddy Land in Aek Simare Irrigation Area, Laguboti District, Toba Samosir Regency, Northern of Sumatera, Indonesia. Jurnal Online PERTANIAN TROPIK, v. 7, n. 1, p. 25-31, 4 Apr. 2020.