Geophysical Technology Innovation to Enhance Soil Fertility and Support Agricultural Productivity in Sumedang, West Java

Abstract Sumedang, located in a hilly region, is a crucial agricultural area in Indonesia. To improve agricultural practices and optimize groundwater accessibility, we employ innovative geophysical technologies, specifically Electrical Resistivity Tomography (ERT) and Electromagnetic Induction (EMI). These methods enable the analysis of Earth’s electrical resistivity at various depths. This study aims to provide a comprehensive overview of the surveyed area by integrating ERT cross-section and EMI-ERT cross-section data into a single map. EMI data acquisition utilized vertical dipole and horizontal modes to investigate deeper (approximately 1.5 m) and shallower (approximately 0.33 m) depths, respectively. Meanwhile, ERT employed the Wenner configuration to obtain dense resistivity values at 0.5 m electrode intervals. Our analysis identified the presence of clay, alluvium, and sandy soil in the region. The EMI acquisition map shows a low resistivity range of 32.89 – 50 Ωm at a depth of 1.5 m and a high resistivity range of 114 – 817 Ωm at depths of approximately 0.33 to 0.75 m. Conversely, the ERT-acquired resistivity map indicates low resistivity values (8.20 – 44.7 Ωm) at depths of 0.637 – 3.94 m for lines 1, 2, and 4, and 0.383 – 2.36 m for lines 3, 5, and 6, with scattered points of high resistivity (58.9 – 817 Ωm) at 0.637 m depth. The presence of water-rich soil at depths greater than 0.75 m suggests the potential for improved soil fertility and expanded irrigation coverage in areas of high resistivity.