Factors Influencing the Physical Characteristics of Peats in West Kalimantan's Forests and Oil Palm Plantations

Peatlands in West Kalimantan play a vital role in regulating water and supporting land productivity, yet they are highly sensitive to changes in hydrological conditions and land use. Peatland areas widely practice drainage and cultivation, which can alter the physical properties of peat and have long-term implications for ecosystem stability and land management. However, how land use and groundwater conditions influence peat physical characteristics across different hydrological settings remains insufficiently understood. This study examined peat physical properties across contrasting hydrological units representing cultivated peatlands and peat swamp forests. Bulk density, water content, and porosity were evaluated in relation to groundwater level, peat thickness, sampling depth, soil suborder, and land use. The results indicate that groundwater conditions and land use are the primary controls of peat physical properties. Peat soils under shallow groundwater conditions consistently exhibited higher water content and porosity, with values exceeding 80%, whereas cultivated peatlands showed lower water retention and porosity compared to forested peatlands. Peat thickness, soil suborder, and sampling depth further influenced the vertical and spatial variability of peat characteristics. Differences were observed both between hydrological units and across soil layers, reflecting pronounced spatial heterogeneity associated with site-specific management. Overall, these findings demonstrate that peat physical properties vary systematically across hydrological units and soil layers, highlighting the importance of hydrology-based and site-specific management strategies to maintain peatland stability and support sustainable land management.