一种土壤电导率实时分析仪的试验研究

开发了一种适合我国较小地块应用的便携式土壤电导率实时分析仪,室内性能试验表明,探针在Wenner组态和Schlumberger组态条件下,仪器输出电压与土壤电导率具有一致的变化趋势,特别是在Schlumberger组态某结构下,传感器获得了最高的测量精度.对实验结果进行了非线性回归建模,采用的3个模型分别是幂函数模型、多项式模型和指数模型,模型分析结果显示,幂函数模型具有最优的预测结果,模型测定系数达到0.994.幂函数模型的常数项与传感器结构有关,乘幂项则不随传感器结构参数变化,而受土壤质地、土壤密度等因素的影响.模型还需要通过田间试验进一步验证.

Testing and modeling of soil EC sensor

A kind of portable soil EC sensor was developed. The performance test of the sensor showed satisfactory result. Voltage drop of the sensor had the same trend as soil EC when four electrodes were set in Wenner structure and Schlumberger structure. The highest precision was obtained under the condition of Schlumberger structure (a=15, b=30). Non-linear modeling was also carried out. The 3 models used were power function, polynomial and index function. The best estimation was obtained in power function model. The determination coefficient reached 0.994. The constant of the model coefficients was depended on the sensor structure while the power of the model coefficients did not show that characteristic. It was shown that soil texture and soil density could have an effect on the power of the model coefficients. A field test is needed to verify the model.