Detection Model for Effect of Soil Salinity and Temperature on FDR Moisture Content Sensors
Bei Liu, Wengting Han, Paul R. Weckler, Yi Wang, Ke Xin Song · Applied Engineering in Agriculture · 2014
Abstract. Soil salinity and temperature are major factors that influence the dielectric properties of soil. To evaluate the effect of these factors on a soil moisture sensor based on dielectric properties, a loess soil sample from Shenmu County, Shaanxi Province, and a sandy soil sample from Dangshan County, Anhui Province, were tested. Two frequency domain reflectometry (FDR) sensors were employed to measure the output for different moisture contents (4.4%-22%), temperatures (5°C-50°C) and salinity levels (0%-1%). The results showed that the indicated moisture output increased with temperature and soil salinity (0%~0.4%), and was relatively stable with salinity (0.4%-1%). A mathematical model relating sensor output, moisture content, salinity, and temperature was established. This model can be used to develop FDR soil moisture sensor calibration equations with temperature and salinity compensation functions.