Electronic Theses and Dissertation

Kualitas tanah merupakan faktor penting yang menentukan produktivitas lahan
pertanian karena memengaruhi ketersediaan air, unsur hara, dan media tumbuh bagi
tanaman. Evaluasi tanah secara konvensional melalui pengambilan sampel
permukaan belum mampu menggambarkan kondisi bawah permukaan secara
menyeluruh. Permasalahan dalam penelitian ini adalah bagaimana interpretasi
model resistivitas listrik 2D dapat digunakan untuk mengkarakterisasi kondisi tanah
serta bagaimana hubungan antara nilai resistivitas dan pH tanah pada lahan
pertanian. Penelitian ini bertujuan untuk mengkarakterisasi kondisi tanah
berdasarkan model resistivitas 2D dan mengkaji hubungan antara nilai resistivitas
dengan nilai pH tanah. Penelitian dilakukan di lahan pertanian Desa Tungkop dan
Desa Cot Iri, Kabupaten Aceh Besar, menggunakan metode resistivitas listrik
konfigurasi Wenner-Schlumberger pada lima lintasan pengukuran dan pengukuran
pH tanah pada beberapa titik sampel. Hasil penelitian menunjukkan bahwa bawah
permukaan tersusun atas zona resistivitas rendah (1 - 15 2m) yang diinterpretasikan
sebagai lempung jenuh air, zona resistivitas sedang (16 - 68 2m) sebagai lempung
pasiran, dan zona resistivitas tinggi (69 - 310 2m) sebagai pasir. Secara umum,
bawah permukaan didominasi oleh lempung jenuh air dan lempung pasiran yang
menunjukkan kualitas tanah baik untuk mendukung kegiatan pertanian. Nilai pH
tanah berkisar antara 6,25 - 7,49 atau termasuk kategori agak asam hingga netral.
Hasil penelitian menunjukkan bahwa semakin rendah nilai resistivitas, kandungan
air dan fraksi lempung cenderung semakin tinggi sehingga kondisi tanah relatif
lebih asam, sedangkan resistivitas yang lebih tinggi berasosiasi dengan pH yang
mendekati netral.

Kata kunci: Karakterisasi tanah, Lahan pertanian, Metode geolistrik, pH tanah,
Res2Dinv.

Soil quality is an important factor that determines agricultural land productivity because it affects the availability of water, nutrients, and a suitable growing medium for plants. Conventional soil evaluation through surface sampling has not been able to comprehensively describe subsurface conditions. The problem addressed in this study is how the interpretation of a 2D electrical resistivity model can be used to characterize soil conditions and determine the relationship between resistivity values and soil pH in agricultural land. This study aims to characterize soil conditions based on a 2D resistivity model and examine the relationship between resistivity values and soil pH. The study was conducted on agricultural land in Tungkop Village and Cot Iri Village, Aceh Besar Regency, using the electrical resistivity method with the Wenner-Schlumberger configuration along five survey lines and soil pH measurements at several sampling points. The results showed that the subsurface consists of a low-resistivity zone (1-15 2m) interpreted as water-saturated clay, a moderate-resistivity zone (16-68 2m) interpreted as sandy clay, and a high-resistivity zone (69-310 2m) interpreted as sand. In general, the subsurface is dominated by water-saturated clay and sandy clay, indicating good soil quality for supporting agricultural activities. Soil pH values range from 6.25 to 7.49, which fall within the slightly acidic to neutral category. The results indicate that lower resistivity values tend to be associated with higher water content and clay fractions, resulting in relatively more acidic soil conditions, whereas higher resistivity values are associated with soil pH conditions that are closer to neutral. Keywords: Soil characterization, Agricultural land, Geoelectrical method, Soil pH, Res2DInv.