TDR法测定土壤含水量的标定研究

CALIBRATION ON MEASUREMENT OF SOIL WATER CONTENT USING TIME DOMAIN REFLECTROMETRY(TDR)

用波兰ET FOM/mts型TDR水份测定仪对封丘地区两种质地土壤在不同的温度和容量条件下进行测定 ,结果表明 ,其介电常数的平方根 (ε)与土壤容积含水量 (θ)有良好的线性关系 (r≥ 0 .997)。标定曲线的误差 (Sθ/ε)范围为 0 .0 0 2～ 0 .0 2 7cm3cm- 3,其中砂质土壤在温度较低 (1 6℃ )条件下的误差最小 ,壤质粘土在温度较高 (2 6℃ )条件下误差最大。

Summary TDR soil moisture instrument (model ET FOM/mts, made in Poland) was calibrated for two types of soil of different texture in Fengqiu region under different treatments of temperature and bulk density. The result show that the relationship between the square root value of dielectrical constant of soil and soil water content in volumatric basis can be well described by linear equations of which the correlation coefficient are equal to or greater than 0.997. Regression errors of the calibration curves range from 0.002 to 0.027 cm 3 cm -3 , and sandy loam soil shows the smallest error at low temperature(16℃), while the biggest error occurs when loamy clay soil is measured at high temperature(26℃).