Kekuatan Geser Tanah pada Empat Kelas Lereng Lahan Tegalan Masyarakat Baduy

Abstract

RIDWAN NUR HIDAYAT. Kekuatan Geser Tanah pada Empat Kelas Lereng Lahan Tegalan Masyarakat Baduy. Dibimbing oleh SRI MALAHAYATI YUSUF dan WAHYU PURWAKUSUMA. Kekuatan geser tanah merupakan faktor penting dalam penentuan stabilitas lereng, terutama di daerah pertanian berlereng. Penelitian bertujuan mengidentifikasi kekuatan geser tanah dan sifat fisik tanah pada empat kelas lereng di Desa Cibungur, Kecamatan Leuwidamar, Kabupaten Lebak, Provinsi Banten. Penelitian dilakukan secara deskriptif eksploratif. Pengukuran dan pengambilan sampel dilakukan pada kedalaman tanah 0–30 cm dan 30–60 cm berdasarkan metode Cluster Random Sampling. Parameter yang diamati adalah kekuatan geser tanah, tekstur tanah, bobot isi, indeks plastisitas, porositas tanah, stabilitas agregat, sensitivitas tanah, dan kandungan C-organik. Hasil penelitian menunjukkan bahwa kekuatan geser tanah pada lapisan 0–30 cm cenderung menurun, sedangkan pada lapisan 30–60 cm kekuatan geser meningkat dengan curamnya lereng. Tekstur tanah, indeks plastisitas tanah, bobot diameter agregat tanah tahan air berdasarkan diameter, bobot isi tanah, dan C-organik tanah memengaruhi kekuatan geser tanah. Seluruh lokasi penelitian memiliki tingkat sensitivitas tanah yang tergolong rendah-sedang, hal ini menunjukkan bahwa risiko keruntuhan tanah akibat gangguan eksternal relatif tidak tinggi, pada lahan berlereng yang dikelola dengan sistem pertanian berbasis kearifan lokal masyarakat Baduy. Hasil penelitian ini menegaskan pentingnya pengelolaan lahan berbasis kearifan lokal seperti masyarakat Baduy, untuk menjaga keberlanjutan lahan dan stabilitas lereng.

RIDWAN NUR HIDAYAT. Shear Strength Characteristics of Soils in Four Slope Classes of Dryland Fields in the Baduy Indigenous Area. Supervised by SRI MALAHAYATI YUSUF and WAHYU PURWAKUSUMA. Shear strength of soil is a key factor in determining slope stability, particularly in sloping agricultural areas. This study investigates the shear strength and physical properties of soil across four slope classes in Cibungur Village, Leuwidamar Subdistrict, Lebak Regency, Banten Province, using a descriptive exploratory approach. Measurements and soil sampling were carried out at two depths of 0–30 cm and 30–60 cm employing the Cluster Random Sampling method. Parameters observed included soil shear strength, soil texture, bulk density, plasticity index, soil porosity, aggregate stability, soil sensitivity, and organic carbon content. The results indicate a trend of decreasing soil shear strength in the upper layer (0–30 cm), while in the deeper layer (30–60 cm), shear strength tends to increase with slope steepness. Factors such as soil texture, plasticity index, diameter-based weight of water-stable aggregates, bulk density, and soil organic carbon significantly influence soil shear strength. All study sites exhibited low to moderate soil sensitivity levels, suggesting a relatively low risk of soil failure due to external disturbances. This resilience is attributed to the local wisdom-based agricultural practices by the Baduy ethnic group, which play a vital role in maintaining land sustainability and slope stability.