Erosion hazard index [EHI] on different land use in sub-watershed Kaos, Jambi

Abstract

Soil degradation that occurs in watershed Batanghari is generally caused by accelerated erosion due to land conversion. Sub-watershed Kaos is one of the sub-watershed from watershed Batanghari that has forest conversion to oil palm plantations is 7,846 Ha from the period 1995-2018. This research aims to assess the Erosion Hazard Index [EHI] on forest land use, land clearing, and oil palm plantation in Sub-Watershed Kaos-Jambi. The data analysis method used the survey method and erosion prediction using the Universal Soil Loss Equation [USLE] model. The EHI was counted by the amount of soil eroded [ton/ha/year] divided by soil erosion that can be tolerated [ton/ha/year]. The result of this research showed that the forest's erosion value is 9.80 ton/ha/year, land clearing is 249.17 ton/ha/year and oil palm plantation is 89.12-122.94 ton/ha/year. The soil erosion can be tolerated on the forest is 36.54 ton/ha/year, land clearing is 57.71 ton/ha/year and oil palm plantation is 54.42-57.49 ton/ha/year. Furthermore, the lowest value of EHI is 0.27 [low grade] and the highest value of EHI is 4.32 [high grade], whereas the EHI value on oil palm plantation is between 1.64 to 2.14 [medium grade]. The EHI in Sub-Watershed Kaos is in low, medium, and high categories. The medium grade and high grade of The EHI will cause soil degradation, such as decreasing soil quality and also loss of organic matter and soil nutrients because of erosion and runoff. Therefore, it must apply soil conservation and agrotechnology application in land clearing and oil palm plantation.