The research was conducted in sandy soil in Selangkun Estate, South Arut Subdistrict, Kotawaringin Barat District, Central Kalimantan Province. The objectives of this research are to know the decomposition of empty fruit bunch (EFB) in covered silt pit in sandy soil and the thickness effects of sandy soil cover on silt pit to the Oryctes rhinoceros population. The research used Completely Randomized Design (CRD) with 5 treatments such as EFB application to soil surface (control), EFB application to silt pit (1.0 m x 0.5 m x 0.5 m) with 0 cm sandy soil (opened silt pit), 10 cm, 20 cm and 30 cm. The observations were done to the decomposition (C/N), nutrient content and O. rhinoceros population. The decomposition of EFB in covered silt pit in sandy soil at various levels of covered sandy thickness was better than control with marked C/N EFB (34.73-36,13), it was significantly lower than control (55,18). The nutrient content of EFB such as Nitrogen (N), Phosphor (P) and Magnesium (Mg) in covered silt pit increased significantly than control. The O. rhinoceros population in silt pit was negatively correlated with the covering sandy thickness. Covered silt pit increased the decomposition of EFB and nutrient content (N, P and Mg), as well as the thickness of the covered silt pit that could affect the O. rhinoceros population.
