Electronic Theses and Dissertation

Erosi tanah merupakan salah satu pemicu utama degradasi lahan, khususnya pada topografi berlereng dengan curah hujan tinggi yang berdampak langsung pada hilangnya unsur hara dan penurunan produktivitas agrikultur. Penelitian ini bertujuan untuk mengkaji dinamika laju erosi berdasarkan variasi jenis tanaman penutup tanah, intensitas curah hujan, dan tingkat kemiringan lereng. Pendekatan eksperimental kuantitatif dilakukan menggunakan rainfall simulator di laboratorium terhadap sampel tanah yang diisolasi dari Desa Pango Deah, Banda Aceh. Desain perlakuan mengintegrasikan tiga tutupan lahan (tanah terbuka, rumput bermuda/Cynodon dactylon, dan rumput gajah mini/Axonopus compressus), tiga tingkat intensitas hujan (92,5; 406,2; dan 481,0 mm jam⁻¹), serta dua tingkat kemiringan lereng (15% dan 45%). Hasil penelitian memvalidasi bahwa peningkatan intensitas hujan dan sudut kemiringan lereng berbanding lurus dengan eskalasi laju erosi. Lahan tanpa tutupan vegetasi mencatat laju erosi tertinggi (12,8–30,2 t ha⁻¹) yang berada pada kategori sangat tinggi. Sebaliknya, kehadiran vegetasi penutup terbukti mereduksi kehilangan tanah secara signifikan. Rumput bermuda menunjukkan efisiensi konservasi terbaik dengan menekan erosi hingga 3,0–4,5 t ha⁻¹ (kategori sedang–tinggi) atau mengalami penurunan rata-rata sebesar 81,0% dibandingkan tanah terbuka, mengungguli rumput gajah mini yang mencatat erosi 4,5–8,6 t ha⁻¹ (kategori tinggi). Kesimpulannya, integrasi tanaman penutup tanah—khususnya rumput bermuda—merupakan langkah konservasi vegetatif yang krusial untuk mendisipasi energi kinetik tetesan hujan, memperlambat kecepatan aliran permukaan (runoff), dan menjaga kelestarian tanah pada lahan miring.
Kata Kunci: Degradasi lahan, erosi tanah, konservasi vegetatif, rainfall simulator, tutupan lahan.

Degradasi lahan, erosi tanah, konservasi vegetatif, rainfall simulator, tutupan lahan. Abstract (English)Abstract. Soil erosion remains a primary driver of land degradation, particularly in high-rainfall regions with sloping topography, leading to severe nutrient loss and declining agricultural productivity. This study aimed to examine the dynamics of erosion rates under varying ground cover types, rainfall intensities, and slope gradients. A quantitative experimental approach was conducted using a rainfall simulator in a controlled laboratory setting on soil samples collected from Pango Deah Village, Banda Aceh. The experimental design encompassed three land cover conditions (bare soil, bermudagrass/Cynodon dactylon, and dwarf carpet grass/Axonopus compressus), three rainfall intensities (92.5, 406.2, and 481.0 mm h⁻¹), and two slope gradients (15% and 45%). The results validated that increments in rainfall intensity and slope steepness are directly proportional to the escalation of erosion rates. Bare soil recorded the highest erosion rate (12.8–30.2 t ha⁻¹), falling entirely into the very high severity category. Conversely, the introduction of vegetative cover significantly mitigated soil loss. Bermudagrass demonstrated the highest conservation efficiency, suppressing erosion to 3.0–4.5 t ha⁻¹ (moderate to high category)—achieving an average reduction of 81.0% compared to bare soil—outperforming dwarf carpet grass which yielded 4.5–8.6 t ha⁻¹ (high category). In conclusion, integrating ground cover crops, specifically bermudagrass, serves as a crucial vegetative conservation strategy to dissipate the kinetic energy of raindrops, decelerate surface runoff, and sustain soil integrity on sloping terrains. Keywords: Land degradation, rainfall simulator, soil erosion, surface cover, vegetative conservation.