干旱荒漠区EC-5土壤水分传感器的校准和应用

应用EC-5土壤水分传感器在沿黄干旱荒漠绿洲地区的风沙土和粘土两种土壤类型中对不同土层深度的土壤含水率进行测定,同时以烘干称重法测定数据为标准值,采用回归分析方法建立EC-5在两种土壤中测定含水率的校准模型。结果表明,风沙土的校准模型为线性函数,且与埋设土壤深度有关,QS=0.71393S+0.01543D+1.71354(R2=0.920,P<0.05),D为土层深度(cm),S为传感器输出值(%);粘土的校准模型则为非线性的,lnQN=1.112S0.316(R2=0.949,P<0.05)。通过模拟回代结果显示,模拟值与标准值间均具有显著的相关性。在EC-5的应用验证阶段,校准值能够反映该地区风沙土和粘土土壤含水率的年变化特征,校准值与传感器输出值之间呈极显著相关关系(P<0.01),说明EC-5土壤水分传感器的校准模型稳定可靠,应用效果良好。

Calibration of EC-5 Soil Moisture Sensors and Its Application in Arid Desertificated Area

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 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（%）,Adjusted R2 equal to 0.920,P0.05.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,P0.05.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（P0.01）,which indicated that the calibration function models of EC-5 sensor are stable and reliable,and good application effects are presented.