基于高密度电阻率成像法的陇中半干旱区土壤含水量监测研究  

A soil water content monitoring in Longzhong semi-arid region by high-density electrical resistivity tomography

作　　者：岳宁[1] 董军[1] 李玲[1] 阚飞[1] 王刚[2] 黄少文[2] 魏国孝[1] YUE Ning DONG Jun LI Ling KAN Fei WANG Gang HUANG Shaowen WEI Guoxiao(Key Laboratory of Western China Environmental Systems, Ministry of Education / College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China College of Water Conservancy ＆ Civil Engineering, Shandong Agricultural University, Tai＇an 271000, China)

机构地区：[1]兰州大学资源环境学院/西部环境教育部重点试验室,兰州730000 [2]山东农业大学水利土木工程学院,泰安271000

出　　处：《中国生态农业学报》2016年第10期1417-1427,共11页Chinese Journal of Eco-Agriculture

基　　金：国家自然科学基金项目(41471023;41202174)资助~~

摘　　要：土壤含水量是影响半干旱区农作物生长的重要因素。为了准确测定土壤含水量的变化动态以指导农业高效用水,近年来,利用地球物理测量方法研究高分辨率的水流入渗,已经越来越受到欢迎和重视。本文以陇中半干旱区玉米田为例,通过在土壤表面布置电极,利用高密度电阻率成像法（ERT）对降雨前后土壤二维剖面进行电阻率数据测量,实现对土壤二维剖面电阻率值和含水量监测,解释不同条件下土壤含水量变化的原因,建立陇中半干旱区农田土壤电阻率和含水量之间的相关关系。结果表明：降水入渗使得二维剖面土壤电阻率整体呈明显降低趋势,反演得到的电阻率图像局部电阻值“高-低-高”的变化过程,与一次降水过程前后“干-湿-干”的循环过程一致。土壤含水量实测值与估计值之间有较为显著的线性关系（R^2=0.651 8,n=96）。在0~2.0 m深度范围内,总体估计偏差较小,为0.74%;土壤含水率的估计精度较高,为2.64%。0~0.5 m土层（H1）含水量监测探头分布密集,数据采集较为准确,故H1层估计精度略高于0.5~2.0 m层（H2）。相比之前利用实测工具进行野外测量,ERT测量方法精度较高。本文提供了一个高分辨率的土壤结构二维分布与水分运移过程的图像,同时为实现精确和高效的农业用水管理提供一种新途径。Soil water content （SWC） is a key factor influencing crop growth in semi-arid regions. Monitoring the variations in SWC is critical for agriculture. In recent years, geophysical survey has been used in the study of high-resolution detection of water infiltration and it is hugely popular because of its zero-damage to soil micro-structure and easy measurement. With a maize field in Longzhong semi-arid region as the case study, we used high-density electrical resistivity tomography （ERT） to measure （before and after the precipitation） two-dimensional electrical resistivity of the column of soil below an electrode placed on the soil surface. Then SWC and electrical resistivity were monitored in two-dimensional soil profile in order to explain the variations in SWC under different conditions and to determine the correlation between electrical resistivity of each soil horizon and its water content in Longzhong semi-arid region. Soil temperature was also discussed in the ERT data interpretation. The results revealed the potential of ERT to improve soil and agronomic studies. Vertical distributions of two-dimensional electrical resistivity image inverted from measured data were different. On the whole, natural rainfall infiltration reduced the trend in two-dimensional electrical resistivity. The trend of local electrical resistivity of the inverted ERT images was one of ＂high-low-high＂, quite consistent with the ＂dry-wet-dry＂ cycle of the precipitation process. Two- dimensional sections of SWC calculated using ERT showed a reliable linear correlation （R^2= 0.651 8, n = 96） between the estimated and measured SWC in the root-zone horizon, with a slope approximately equal to 1. Within the depth range of 0-2.0 m, the precision of the calculated specific SWC quantified by the root mean square error （RMSE） was 2.64%, with a bias corresponding to an overestimation of 0.74%. The densely distributed SWC detectors installed in the H1 horizon （0-0.5 m） enhanced precise data collection, resulting in b

关 键 词：电阻率成像 土壤含水量 降水入渗 非饱和土壤 时域反射 陇中半干旱区 

分 类 号：S125[农业科学—农业基础科学]