Accuracy Analysis and Evaluation of Four Common Soil Moisture Sensors

In view of inefficiency of agricultural production caused by much different measured results of different sensors on the market，four soil moisture sensors （numbered A，B，C，and D） commonly available on the market were selected to perform indoor and field tests to test accuracy of sensor.Test results showed that measured result of sensor B was the closest to true water content of soil （comprehensive error was 5.14%），and difference between measured values of other three sensors and true water content was too large （comprehensive deviation was greater than 9%）.In addition，test results also showed that sensor′s measurement results for soil with the same water content would change when test environment changed，and sensor measurement error value would corresponding change.Error value changed under certain conditions was quite obvious.Test also showed that sensor manufacturer has a limitation on initial calibration of sensor.If user need more accurate results，it is essential to correct sensor again.