This study aims to determine the interaction and effect of the main treatment of various liquid organic fertilizers and NPK 16:16:16 on the growth of oil palm seedlings in the main nursery. This research was carried out at the Integrated Agricultural Unit of the Islamic University of Riau (UPT-UIR), Jalan Sekolah, RT 02/RW 03, Desa Kuabng Jaya, Kec. Siak Hulu, Kab. Kampar. This research lasted …