Rancang Bangun Sistem Pengamatan Suhu Tanah Digital Berbasis Internet of Things di Stasiun Klimatologi Sumatera Utara

Abstract

Soil temperature, as one of important parameters in monitoring and understanding climate and soil ecosystems, has a crutial role in various aspects of the environment, including agriculture, ecology, and geoscience. Monitoring soil temperature is required for planning and managing agriculture and natural resources. Currently, temporally, ground temperature observations by BMKG (Meteorologyl, Climatology, and Geophysics Agency) are still limited, namely only carried out at 07:55, 13:55, and 18:55 local time. This makes it difficult to carry out soil temperature analysis. This research is carried out to design a digital soil temperature observation tool that can be accessed via the internet network. A set of seven DS18B20 sensors, at depths of 0 cm, 2 cm, 5 cm, 10 cm, 20 cm, 50 cm, and 100 cm respectively are combined with the ESP8266 module using the Arduino system. The implementation of the design produces a real-time soil temperature observation system every 10 seconds. Observation data is displayed on a 20x4 LCD and sent to the cloud so that it accessed on the web page http://monitoringsuhutanah.my.id. The calibration results state that the DS18B20 sensors used in this research produces accurate and consistent temperature measurements with an average correction ranging from (-0.20) to 0.24, making it suitable for operation. Field tests results show that digital data is accurate and in agreement (linearly correlated) with conventional data. This is based on the correlation value which reaches 0.7, while the RMSE value ranges from 0.5 to 2.18, and bias ranges from (-0.69) to 0.08. Temporal analysis shows the diurnal pattern of soil temperature, namely peaks in the afternoon and valleys in the evening and early morning. It can be seen that the soil temperature in the surface layer (0 cm, 2 cm, and 5 cm) has the highest variability, while the soil temperature in deep layers (50 cm and 100 cm) appears more unvarying. In addition, effect of solar radiation and rain on soil temperature variability analysis is also carried out. The result is that an increase in solar radiation causes an increase in soil temperature, while the occurrence of rain in the morning and afternoon causes a low soil temperature.