FORMULATION OF SOIL EROSION MITIGATION BASED ON SOIL EROSION DYNAMICS AND COMMUNITY PERCEPTION IN MERAWU SUB WATERSHED, BANJARNEGARA DISTRICT, INDONESIA

Sekar Jatiningtyas, Prof. Dr. Junun Sartohadi,

2012 | Tesis | S2 Geografi

Bahaya erosi tanah dan persepsi masyarakat merupakan alat untuk memformulasikan mitigasi erosi tanah. Metode penentuan tingkat erosi tanah yang digunakan adalah RMMF dan pengumpulan data persepsi masyarakat Tujuan dari penelitian ini adalah untuk memetakan dan menganalisa dinamika erosi tanah di Sub DAS Merawu, untuk mengidentifikasi persepsi masyarakat mengenai erosi tanah, untuk mempelajari keterkaitan antara dinamika erosi tanah dengan persepsi masyarakat terhadap erosi tanah di Sub DAS Merawu, dan untuk memformulasikan mitigasi erosi tanah supaya erosi tanah di Sub DAS Merawu terminimalisir. melalui wawancara. Metode RMMF memerlukan beberapa nilai parameter dari faktor curah hujan, bentuk lahan, tanah, dan penggunaan lahan; yang diperoleh dari survey lapangan, pengumpulan data sekunder, dan analisis laboratorium. Selanjutnya persepsi masyarakat dianalisis secara deskriptif. Tingkat erosi tanah tertinggi berada di bagian tengah Sub DAS Merawu karena penggunaan lahan dominan di daerah tersebut berupa tegalan yang memiliki penutup kanopi jarang. Rendahnya persepsi masyarakat terhadap erosi tanah berdampak pada pengelolaan lahan tanpa memperhatikan mitigasi erosi tanah. Sebaliknya, erosi tanah di bagian hulu rendah karena adanya hutan lindung yang dikelola oleh pemerintah. Meskipun sebagian kecil informan memiliki persepsi baik terhadap erosi tanah, tingkat erosi di bagian hilir rendah. Hal tersebut karena adanya penggunaan lahan berupa kebun campur yang tutupan kanopinya baik untuk melindungi permukaan tanah dari tetesan hujan dan limpasan permukaan. Erosi tanah adalah proses yang dinamik. Nilai tingkat erosi tanah di tahun 2001 sebesar 224,91 ton/ha/th; di tahun 2006 sebesar 96,54 ton/ha/th; dan 148,89 ton/ha/th di tahun 2010. Variasi persepsi masyarakat mempengaruhi variasi pengolahan lahan oleh masyarakat, sehingga menyebabkan variasi tingkat erosi tanah. Mitigasi erosi tanah merupakan hal yang penting untuk diformulasikan untuk meminimalisir resiko erosi tanah. Strategi mitigasi yang direkomendasikan adalah kombinasi antara hard mitigation (metode mekanik dan metode vegetativ) dan soft mitigation (memperkuat kerjasama antar stakeholders, menentukan perencanaan penggunaan lahan dengan mempertimbangkan aspek erosi tanah, dan meningkatkan pengetahuan masyarakat melalui pendidikan).

The objectives of this research were 1) to map and to analyze soil erosion dynamic in Merawu sub-Watershed, 2) to identify community perception on soil erosion, 3) to study the relation between soil erosion dynamics and community perception on soil erosion in Merawu sub-Watershed, and 4) to formulate the soil erosion mitigation to reduce soil erosion in Merawu sub-Watershed. The assessment of soil erosion hazard and community perception are the tool to formulate soil erosion mitigation. RMMF was employed to assess erosion rate and interview was employed to assess community perception. RMMF method requires the parameters value of rainfall, landform, soil, and land use; that was acquired by field surveying, secondary data collecting, and laboratory analysis. Moreover, community perception was analyzed descriptively. highest soil e The rosion rate was in middle stream of research area because this area dominantly by dry field land use that has rare canopy. Some community in this area had low perception on soil erosion and managed the land by unconsider on soil erosion mitigation. On the contrary, soil erosion hazard in upstream was low because this area was established as the protective forest that is managed by the government. Although only few of the informants had good perception on soil erosion, soil erosion hazard in downstream was low. It was because the dominant land use was mixed garden that has layered canopy to protect soil surface from the attack of raindrop and runoff. Soil erosion was dynamic process. The value of soil erosion rate were 224.91 ton/ha/year in 2001, 96.54 ton/ha/year in 2006, and 148.89 ton/ha/year in 2010. There were a variation of community perception that influenced the variation of land management by community and it caused the variety of soil erosion hazard. Proper soil erosion mitigation was crucial to be formulated to reduce soil erosion risk. The recommended mitigation strategy is the combination between hard mitigation (mechanical method and vegetative method) and soft mitigation (strengthen partnership, established land use planning considering soil erosion matter, and improve community knowledge by education).

Kata Kunci : soil erosion, RMMF, community perception, mitigation