EVALUATING SOIL QUALITY ACROSS MULTIPLE SOIL TYPES FOR SUSTAINABLE OIL PALM PLANTATIONS IN CENTRAL KALIMANTAN, INDONESIA

Assessing soil quality is essential to ensuring the long-term sustainability of oil palm plantations by aligning agricultural productivity with environmental and social dimensions.This study examines the influence of soil type on soil quality in Kotawaringin Timur District, Central Kalimantan, Indonesia.Specifically, it evaluates four representative soil types (Histosols, Inceptisols, Ultisols and Entisols) using the soil quality index (SQI) framework, identifies key indicators through a minimum data set (MDS), and proposes soil-specific management strategies.The methodology includes field surveys, biological and physicochemical soil analyses, SQI computation and statistical evaluation, with six replications per soil type.Results demonstrate significant variation in SQI values: Low for Histosols (0.245) and very low for Ultisols (0.178), Inceptisols (0.180) and Entisols (0.182).Soil organic carbon (SOC), exchangeable magnesium (Ex-Mg) and available phosphorus (Av-P) were identified as critical indicators influencing soil function.To improve soil quality, the application of organic amendments such as compost, biochar and biofertilisers derived from oil palm residues is recommended.Integrating weed biomass may further enhance nutrient availability and soil resilience, supporting sustainable plantation management tailored to site-specific conditions.