Abstract: 〖WT5HZ〗Abstract：〖WT5BZ〗The soil water content in different soil depth of the sandy soil and clay soil respectively in Ulan Buh desert were measured with the EC-5 sensors,simultaneously the soil moisture content were also measured with the weighting method after dried which were taken as the standard value of soil water contentThen many linear or curves regression process were conducted to 〖JP2〗establish the calibration function models.The results showed that the calibration function for the sandy soil was the linear model,which was also relative to the soil depth.The calibration model for the sandy soil was QS=0.71393S+0.01543D+1.71354,in where D is soil depth(cm),S is the sensor output value (%),〖JP〗Adjusted R2 equal to 0920,P<0.05.The calibration function for clay soil was the nonlinear model.The calibration model for the clay soil was lnQN=1.112S0.316,in where Adjusted R2 equal to 0.949,P<0.05.After the simulation of back substitution,the high correlation between the simulated value and the standard value were revealedIn the period of the application and verification of the calibration function models,the annual change characteristics of the soil water content in sandy soil and clay soil were presented,and the very significant correlation between the calibrated value and the sensor output value exists（P<0.01）,which indicated that the calibration function models of EC-5 sensor are stable and reliable,and good application effects are presented.

Key words: EC-5 soil moisture sensor, Calibration, Arid desertificated area, Soil type