Pengaruh Penambahan Bahan Organik Pada Tanah Ultisol Terhadap Pertumbuhan Acacia Mangium Willd Di Polybag

Mangium is a legume species that grow in the tropics on various soil types, including poor nutrient soils such as ultisols. Ultisols have a highly leached surface layer with a relatively coarse texture, low in organic matter content, low base saturation and low pH. This study aims to determine the growth of Acacia (Acacia mangium Willd) seedlings on various compositions of planting media in polybags.This research was carried out for three months, from December 2020 to February 2021 at the Permanent Nursery of BPDASHL Palu Poso, Tadulako University Campus, Central Sulawesi. The experiment method is Complete Randomized Design with four treatments: M1 = Ultisol soil + goat manure (2 : 1), M2 = Ultisol soil + Cocopeat (2 : 1), M3 = Ultisol soil + husk charcoal (2 : 1), M4 = Husk charcoal + Cocopeat (2 : 1), with 10 replications, so that the seedlings tested were 40 units. The parameters observed in this study were height, diameter, number of leaves, and the seedling sturdiness. Analysis of variance or F test was used to determine the significant effect of treatment on the growth of acacia seedlings. The Tukey Test (BNJ 5%) is used to determine the significant differencies between treatments on the observed growth parameters, namely seedling height, stem diameter, number of leaves and the value of stem sturdiness.The result of study showed the treatment composition of the growing media had a significant effect on the observed seedling growth parameters. Treatment of ultisol soil + husk charcoal 2:1 (M3) have better growth in height (11.34 cm) and stem diameter (1.39 mm) than treatment of ultisol soil + goat manure 2:1 (M2), ultisol soil + cocopeat 2:1 (M1) and treatment of husk charcoal+cocopeat 2:1 (M4).