Pengaruh Pemberian Pembenah Tanah (Abu Boiler) dan Pupuk Npk Terhadap Pertumbuhan Bibit Kelapa Sawit (Elaeis guineensis Jacq) Pada Tanah Ultisol di Polybag

Abstract

Applying boiler ash as a soil alongside NPK fertilizer to Ultisol soil is a strategy to reduce an inorganic fertilizers usage without redusing on crop productivity. This study had conducted both at the Experimental field of Agriculture Faculty and Basic Laboratory of Batanghari University, Jambi, from October 2025 to January 2026. The objective was to determine the effect of boiler ash and NPK fertilizer applications on the growth of oil palm (Elaeis guineensis Jacq.) seedling in Ultisol soil within polybags. A Completely Randomized Design (CRD) was applied, featuring a single factor with six treatment levels and three replications: (k0) control (no boiler ash and NPK fertilizer); (k1) 100% boiler ash (75 g); (k2) 100% NPK (10 g); (k3) 75% boiler ash (56.25 g) + 25% NPK (2.5 g); (k4) 50% boiler ash (37.5 g) + 50% NPK (5 g); and (k5) 25% boiler ash (18.75 g) + 75% NPK (7.5 g). Observed parameters included plant height, stem diameter, total leaf area, shoot dry weight, root dry weight, growing medium moisture content, seedling quality index, and leaf color. Data were analyzed by Analysis of Variance (ANOVA) followed by DNMRT post-hoc testing at the 5% significance level. The application of boiler ash soil Improvement and NPK fertilizer in treatment k5 (25% boiler ash [18.75 g] + 75% NPK [7.5 g]) which resulted 45.26 cm of plant height (30% increase), stem diameter of 27.00 mm (108% increase), total leaf area of 834.99 cm² (209% increase), shoot dry weight of 23.51 g (202% increase), root dry weight of 5.87 g (215% increase), and seedling quality index of 5.28 (277% increase), all compared to the untreated one (control). Treatment k5, involving the application of 25% boiler ash, allowed for a 25% reduction in NPK fertilizer usage.