Analysis of Soil Quality for Hydrological Disaster Mitigation in Sub-Watershed of Krueng Jreue, Aceh Besar Regency-Indonesia

Land conversion of forest to non-forest has led to a reduction in soil fertility, exhibited by a lower soil quality index value (SQI) in the Sub-Watershed of Krueng Jreue. This research aimed to determine soil quality associated with various land uses using the SQI value approach. SQI calculated based on the criteria proposed by Mausbach & Seybold (1998), which is suitable for field conditions using analysis of Minimum Data Set (MDS). The parameters analyzed include rooting depth, soil texture, bulk density, total porosity, pH of the soil, C-organic, N-total, P-available, K-exchangeable and soil respiration. The result showed that the quality criteria of the soil consist of three classes: low, medium and high, which have soil quality index values of 0.27, 0.52, and 0.64 respectively. The area of research was mapped accordingly by class: (1) high, covering an area of 14016.98 ha (60.38%); (2) medium, covering an area of 8542,90 ha (36.79%); and (3) low, covering an area of 658,18 ha (2.83%). Types of land use categorized as having high quality are primary forest, secondary forest and residential area with respective values of 0.66; 0.64, and 0.63. Open land, grassland, moor, rice field and shrubs were of medium quality, with respective values of 0.47; 0.48; 0.52; 0.51 and 0.55.