基于探地雷达快速测定土壤含水量试验研究

试验点选择在古尔班通古特沙漠南缘中国科学院阜康荒漠生态系统研究站,以探地雷达为主要数据采集工具。结合探地雷达两种测量方式特点,提出了探地雷达最佳天线间距判定方法,达到快速测定中尺度土壤水分含量的目的。研究结果表明:固定天线间距测量下,得到最佳天线间距为1.9 m,提取了该天线间距下的地面波,进行了土壤含水量计算,测线上30.5 m点测定的土壤含水量与标后的时域反射仪法结果对比,在该试验点探地雷达地面波法测定上层土壤含水量的有效深度为20 cm,其偏差仅为0.015 m³/m³,精度能够满足实际需求,测线0~36.5 m间沙地上层土壤含水量表现出空间异质性,该方法能快速精确测定中尺度土壤含水量,为农业生产和作物灌溉提供科学依据。

A Study of Fast Estimating Soil Water Content by Ground Penetrating Radar

This experiment was conducted at Fukang Station of Desert Ecology of Chinese Academy of Science located in the southern part of Gurbantunggut Desert, and ground penetrating radar (GPR) is used as the main data acquisition tool. Combined the character of the two measurement methods of ground penetrating radar, a determination method of optimal fixed offset is presented and the goal of fast estimating soil water content can be achieved. The result showed that: 1.9 m was determined as the optimal fixed offset by fixed offset measurement, the ground wave of this fixed offset was picked and soil water content was calculated, and the estimating water content at 30.5 m on survey line is compared with the result of Time Domain Reflectometry, 20 cm is the effective detecting depth for GPR ground wave to estimate the soil water content in the experimental site, and deviation is only 0.015 m³/m³, the accuracy can meet the actual demand, the average water content of the upper sandy showed spatial heterogeneity from 0 to 36.5 m on survey line. This method can estimate mesoscale soil water content fast and accurately, which can provide a scientific basis for agricultural production and crop irrigation.