Design and Development of a Soil Quality Evaluation Device and Software for Sweet Potato (Ipomoea batatas) Cultivation

Background: Sweet potato (Ipomoea batatas) is a vital root crop in the Philippines that contributes significantly to food security and rural livelihoods. However, many farmers still rely on traditional soil assessment methods, which may not accurately determine soil suitability for cultivation. Existing soil analysis systems are often costly, complex, and dependent on laboratory testing or multiple sensing parameters, limiting their accessibility to small-scale farmers. Objectives: This study aimed to develop SoilQA (Sweet Potato Soil Quality Analyzer), an Arduino-based device capable of measuring soil humidity and pH levels, and a desktop application that evaluates soil suitability for sweet potato cultivation based on established agronomic thresholds. Method: A developmental research design was employed involving hardware and software development. The system integrated soil humidity and pH sensors with an Arduino microcontroller for real-time data acquisition. Twenty (20) soil samples collected from agricultural areas in Maydolong, Eastern Samar, were analyzed using repeated sensor measurements and calibration procedures to ensure reliability. System usability was evaluated using the System Usability Scale (SUS) with 25 farmers and 15 agricultural personnel. Findings: The developed system successfully collected and processed soil data and generated automated suitability recommendations. Of the 20 soil samples analyzed, 9 (45%) were classified as suitable and 11 (55%) as unsuitable for sweet potato cultivation due to low soil moisture or pH imbalance. The device recorded 120 readings per parameter within a two-hour testing period. Usability evaluation yielded a SUS score of 77.5, corresponding to a “Good” rating. Novelty: SoilQA introduces a simplified, crop-specific soil evaluation approach focused on soil humidity and pH, the two critical parameters for sweet potato cultivation. Unlike existing multi-parameter and IoT-dependent systems, it combines portable sensing with an offline decision-support application, providing a low-cost, accessible, and farmer-friendly solution for localized agricultural use. Keywords: Soil analysis, Arduino, soil humidity, pH level, sweet potato, precision agriculture, decision support system