EVALUASI PERBANDINGAN PENGENDALIAN GULMA SECARA MANUAL DAN BERBASIS HERBISIDA PADA TANAMAN KELAPA SAWIT BELUM MENGHASILKAN

The presence of weeds during the immature oil palm phase (Immature Oil Palm/IOP) poses a significant challenge because it prolongs the non-productive period through competition for nutrients, light, and water. This study aimed to evaluate the effectiveness of several weed control methods against the dominant weed species, Paspalum conjugatum and Asystasia gangetica, within the weeding circle of immature oil palm plantations. The research was conducted at Johan Sentosa Estate, PT Agrinas Palma Nusantara. A quantitative approach was employed using a non-parametric experimental design based on independent observational units with three treatments: manual weeding (weeding circle scraping), glyphosate + metsulfuron-methyl application (450 mL ha⁻¹ + 22.7 g ha⁻¹), and paraquat + metsulfuron-methyl application (450 mL ha⁻¹ + 22.7 g ha⁻¹), each replicated ten times. The observed parameters included weed mortality, weed regrowth, phytotoxicity, and operational costs. Data were analyzed using the Kruskal–Wallis and Mann–Whitney tests at a 5% significance level. The results showed significant differences among treatments (p < 0.05). Manual weeding produced the highest initial weed mortality (mean rank = 15.50) but incurred the highest operational cost, amounting to IDR 589,621.45 ha⁻¹ year⁻¹. The application of glyphosate + metsulfuron-methyl provided the most effective suppression of weed regrowth up to the eighth week after treatment (mean rank = 15.50) at a cost of IDR 355,056.61 ha⁻¹ year⁻¹, while paraquat + metsulfuron-methyl demonstrated nearly comparable effectiveness at a lower cost of IDR 339,397.25 ha⁻¹ year⁻¹. None of the treatments caused phytotoxic symptoms (score = 0) on the oil palm plants. The combination of glyphosate and metsulfuron-methyl was identified as the most effective and cost-efficient weed control method for the weeding circle of immature oil palm plantations.
Keywords : oil palm; immature stage; weed control; glyphosate; paraquat.