PENDUGAAN EROSI MENGGUNAKAN METODE UNIVERSAL SOIL LOSS EQUATION (USLE) DI DAS RANU PANI KAWASAN TAMAN NASIONAL BROMO TENGGER SEMERU

Abstract

The land problem that commonly occurs in Ranu Pani Watershed is erosion. Ranu Pani Watershed is an area located in the mountains with very high soil erosion. Therefore, it is necessary to conduct good management in the upstream and downstream areas. The first step before carrying out the management is to analyze the occurrence of erosion in the Ranu Pani Watershed. The purpose of this research was to predict the potential erosion and the distribution of spatial data.. The results of the research showed that the erosivity value in the Ranu Pani Watershed was 961.44 and heavy to very heavy class (0.50-0.77) of erodibility, soil texture was dominated by silt, fine granular soil structure, and moderate dominant permeability. 56.80% of the area (158.27 ha) has a slop class III (15-30%) with the land cover are natural forest with lots of litter, grasslands, shrubs, and fields of onions and potatoes. Land management is managed cultivation follows the contour line but without conservation. The result of the calculation showed that almost all areas have potential erosion value exceed the permissible erosion determination, with the potential erosion value are 1.92-4246.28 tha^-1 yr^-1, the range of permissible erosion value are 0.029- 1.2 tha^-1 yr^-1, and the erosion hazard index value is 1.57-143442.49. The results of the spatial analysis showed that 64.39% of the area (179.41 ha) has a very heavy erosion hazard class and 69.50% of the area (193.66 ha) has a very high erosion hazard index.