Design and Calibration of a Low-Cost SDI-12 Soil Moisture Sensor

Area of Science:

• Agricultural Engineering
• Soil Science
• Sensor Technology

Background:

• Water scarcity is a primary constraint in agriculture, necessitating efficient irrigation management.
• Accurate soil moisture measurement is crucial for optimizing water use in farming.
• High costs of commercial soil moisture sensors limit adoption by many farmers.

Purpose of the Study:

• To design, develop, and calibrate a cost-effective capacitive soil moisture sensor.
• To integrate SDI-12 communication for versatile soil calibration.
• To evaluate the sensor's accuracy, variability, and performance in field conditions.

Main Methods:

• Development of a novel capacitive soil moisture sensor with SDI-12 interface.
• Calibration of the sensor across three distinct soil types.
• Comparative accuracy assessment against commercial soil moisture sensors.
• Field testing to evaluate temperature effects and event detection capabilities.

Main Results:

• The developed sensor demonstrated lower accuracy compared to commercial units but offered significant cost savings.
• Sensor calibration equations were successfully adapted for different soil types.
• Field tests confirmed the sensor's ability to reliably detect irrigation and rainfall events.
• Temperature variations were observed to influence sensor readings.

Conclusions:

• The low-cost soil moisture sensor provides a viable, budget-friendly alternative for farmers.
• SDI-12 integration enhances the sensor's adaptability to various soil conditions.
• The sensor effectively supports efficient irrigation management by detecting water availability and events.
• Further research may refine accuracy and mitigate temperature-related influences.