Kajian Tingkat Bahaya Erosi (TBE) pada Pengunaan Lahan Tanaman Agroforestry di Sub DAS Lau Biang (Kawasan Hulu DAS Wampu)

Abstract

HARRY PRANATA BARUS, “The Study of Erosion Hazard Level (TBE) at Agroforestry Land at Sub DAS Lau Biang (Headwaters of DAS Wampu)”, supervised by EDI SUSANTO and SAIPUL BAHRI DAULAY. The transferring of function of forest land of agriculture cultivation at the headwaters of DAS Wampu, especially at Sub DAS Lau Biang has resulted increase of erosion rate at this DAS. Therefore, research was carried out at the agroforestry land from April-July 2009 by using the USLE and the Small square methods by taking 10 subdistricts for sampling. The observed parameters were the kind of soil, the effective depth of soil, soil permeability, soil C-organic content, soil texture, soil structure, slope and rainfall. The results showed that the transferring of function of forest land into agroforestry affected the amount of erosion occurred. The average erosion occurred according to the predictive method was 184,474 ton/ha.year, and according to small squares method was 20,418 ton/ha.year that was smaller than the USLE method.