| A simple and exact method for laboratory calibration of TDR(Time domain reflectometry) is introduced.It has many advantages,such as less work intensity,hardly any spatial heterogeneity of soil moisture and more suitable for calibration on clay loam soil,compared with traditional calibration methods.Through the calibration for clay loam soil from Kunshan region,the results show that the measured values of TDR are obviously lower than that of the oven drying method(ODM),with a range of absolute deviation from 1.9%～8.8%(average 5.0%),and its relative deviation increases with the decrease of soil moisture.But,there is a high correlation between the measured value of soil moisture using TDR and ODM (R2=0.9837,P<0.001),which can be described by a simple linear function.The prediction equation can be used in Kunshan region as reference. |