The characteristics of soils impacted by the Merapi eruption in Plawangan Hill of Mount Merapi National Park, Yogyakarta, Indonesia

Abstract

Mount Merapi National Park (TNGM) is one of the active volcanos in Indonesia. It has past volcano eruption history since 1911 up to date. Specifically, Plawangan Hill, a part of the TNGM, has periodically experienced volcanic eruptions. This study aimed to examine the quantities of nutrients in the soil and the vegetation growth in affected areas and to estimate when it would be feasible to start planting on Plawangan Hill shortly after a volcanic eruption. A field survey and a soil laboratory examination were conducted to obtain the data. Plawangan Hill’s Digital Elevation Model (DEM) was classified from very low to very high classes, while the Digital Surface Model (DSM) was categorized from flat to very steep slopes. The results demonstrated that the pH of the soil was typically somewhat acidic (5.93-6.54), while the soil’s nitrogen content was found to be low to medium, and both phosphorus and potassium levels were typically very low. The carbon-to-nitrogen ratio was generally categorized into the medium, while the organic C ranged from low to medium (1.44% to 3.22%). The soil’s total N, total K, organic matter, carbon, and C:N ratio increased by the erupted material age. The vegetation growth was excellent in indirect (IA) and directly affected (DA) conditions, as indicated by their diameter at breast height (Dbh) and height (H). The correlation between soil characteristics and vegetation growth differed in IA and DA areas. This study found that Plawangan Hill’s land cover in 2023 varied from low to high regarding vegetation classifications. As a result, volcanic materials significantly contributed to Plawangan Hill’s soil characteristics and vegetation growth. The soil needed at least four years to recover and support vegetation growth following a volcanic eruption.