Analisis Laju Infiltrasi pada Hutan Pinus (Pinus merkusii) dan Hutan Primer di Kabupaten Mamasa

Abstract

Changes in vegetation cover due to human activities and forest management practices can significantly affect hydrological processes, particularly soil infiltration. Infiltration plays a vital role in maintaining groundwater availability, controlling surface runoff, and preventing erosion. A decline in infiltration capacity may reduce groundwater recharge and increase flood risk in upstream areas. This study aims to analyze and compare the infiltration rates between Pine Forests (Pinus merkusii) and Primary Forests in Mamasa Regency, West Sulawesi, which serves as an important water catchment area in the mountainous region. This research employed a comparative descriptive approach using field observation methods. Infiltration was measured using a Double Ring Infiltrometer at three observation points in each forest type. Measurements were recorded every five minutes for one hour to determine the initial (f₀) and constant infiltration rates (fc) using the Horton (1940) equation. The average infiltration rates between the two forest types were then compared statistically. The results showed that the average infiltration rate in the Primary Forest was 95.7 mm/hour, whereas in the Pine Forest it was only 46.8 mm/hour, indicating a significant difference (p < 0.05). The higher infiltration rate in the primary forest is attributed to its looser soil structure, higher organic matter content, and greater soil biota activity, in contrast to the pine forest which has a thick layer of slowly decomposing litter that limits water percolation. It can be concluded that vegetation cover significantly influences soil infiltration capacity. The primary forest demonstrates a better water absorption capacity compared to the pine forest, thus playing a crucial role in maintaining hydrological balance and groundwater conservation in the mountainous areas of Mamasa Regency.