CONSTRUÇÃO E USO DE SONDAS DE UMIDADE DE BAIXO CUSTO PARA MONITORAMENTO DA ÁGUA NO SOLO

Abstract

The adoption of accessible technologies, such as Arduino and moisture sensors, enables efficient irrigation management, reducing water and energy waste, increasing productivity, and promoting sustainability in agriculture. This study aimed to build and test a resistive soil moisture sensor, coupled with an Arduino system, as a low-cost alternative for continuous soil water monitoring in Dystrophic Litholic Neosols. Initially, calibration tests were performed in the laboratory using pots with different soil densities and simulated electrical conductivities. The HD-38 sensors were connected to the Arduino microcontroller, and moisture data were compared with the pots' mass loss. The data were fitted using linear regression, resulting in a model with a coefficient of determination (r²) of 0.96. After calibration, the probes were installed in the field, in an area cultivated with watermelon, and tested under four treatments: control, Australian Leonardite, Bacillus aryabhattai, and a combination of both bioinputs. Readings were collected automatically hourly from October to December 2024. Statistical analysis of the data revealed significant differences between treatments, particularly the performance of Bacillus aryabhattai in dry periods and Leonardita in irrigation. The probes performed well in detecting moisture variations even under diverse environmental conditions, demonstrating their effectiveness when properly calibrated. The developed system proved to be technically and economically viable, as well as promising for use by smallholder farmers and in experimental research.