Karst rocky desertification delineation and estimation of potential soil loss in tropical karst cockpits

Tropical cockpit karst, characterized by hilly topography, steep slopes, and thin soil layers, is highly susceptible to land degradation in the form of karst rocky desertification (KRD). KRD occurs due to acute soil erosion in karst environments, leading to the exposure of bedrock. This study aims to provide a comprehensive analysis of KRD, accurately assess soil erosion rates in cockpit karst landscapes, and identify the contributing factors. The research was conducted within the Seropan underground river catchment area in the Gunungsewu Karst region. KRD was identified using an image transformation approach employing the Karst Rocky Desertification Index (KRDI). Soil loss estimation was performed using the updated Revised Universal Soil Loss Equation (RUSLE) method, incorporating the KRD factor to enhance its applicability in karst environments. The results demonstrate that KRDI is highly effective in identifying KRD. Approximately 40 % of the study area exhibits moderate to severe KRD levels, predominantly found on the slopes of conical hills, where the primary driving factors are deforestation, land clearing for dryland agriculture, and abandonment of agricultural land. The estimated total soil loss in the study area is 4975.01 tons per year, with the highest contribution occurring at the intense soil loss level. The intense to extremely intense-severe soil loss levels are correlated with the steep slopes of conical hills, highlighting the significant role of topography in soil degradation within tropical karst environments.