Electrical Properties of Soil in Bohol:  Basis for Automated Irrigation System

Ryan Carlo  Lapuag,

Electrical Properties of Soil in Bohol: Basis for Automated Irrigation System

Abstract:

Irrigation is vital for Philippine agriculture, particularly in regions like Bohol, where water resources are under pressure due to competing demands and seasonal droughts. Despite introducing automated irrigation technologies designed to enhance efficiency, many areas still need to rely on updated manual methods, leading to water wastage and reduced productivity. This study explores the potential of automated irrigation systems to improve water use efficiency by evaluating soil's physical and electrical properties in Bohol's greenhouses. Specifically, it investigates soil texture, bulk density, pH, moisture content, and the performance of resistive and capacitive soil moisture sensors under varying conditions. Using a randomized complete block design, the research analyzed soil samples from greenhouses in six municipalities: Antequera, Bilar, Calape, Carmen, Jagna, and Loay. Laboratory experiments assessed soil properties, and a custom Arduino-based soil moisture meter was developed for sensor calibration. The study found significant variability in soil properties across locations, with sandy clay loam soils exhibiting the highest electrical resistivity and lower water retention than silty clay and clay soils. The findings highlight that soil pH varied from slightly basic to strongly acidic, and sensor voltage output inversely correlated with soil moisture content, reflecting changes in electrical conductivity. The results underscore the importance of selecting appropriate sensors and calibration methods for accurate soil moisture measurement. Recommendations include further testing for sensor variability, preference for capacitance over resistive sensors, and rigorous calibration procedures. Enhancing these practices will improve the effectiveness of automated irrigation systems and support sustainable agricultural development in Bohol.

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