Calibration on Measurement of Soil Water Content Using Time Domain Reflectometry(TDR) in Yangzhou Area

The relationship between drying method and TDR method on different soils was studied in Yangzhou area by Sepctrum TDR 100.The experiment proves that measured value is close to true value while the soil bulk density is about 1.3 g/cm3;when the soil bulk density is lager or smaller,deviation would be larger.TDR measured value is closed to oven drying method when clay content is 0~200 g/kg and sand content is 300~500 g/kg.TDR can be directly used in the soil water content measurement on the sand and the loam,but it must carry on the coefficient conversion above the clay loam and the clay,the clay loam determination result must divide 1.18 and the clay 1.44.