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介电管式传感器与中子水分仪同腔共射原位测定农田冰/水含量

发表时间:2016-02-15  浏览量:2338  下载量:823
全部作者: 程强,孙宇瑞,秦玉龙,薛绪掌,蔡祥,盛文溢,赵燕东
作者单位: 中国农业大学农业部农业信息获取技术重点实验室;国家农业信息化工程技术研究中心;北京林业大学工学院
摘 要: 土壤液态含水量(liquid soil water content,LSWC)、土壤总含水量(total soil water content,TSWC)及土壤含冰量(soil ice content,SIC)是寒冷地区土壤水动态的主要研究对象。而土壤含冰量的测量与其他2个量相比更具挑战性,目前没有可行的测量方法。基于此,本研究提出将中子水分仪(neutron moisture meter,NMM)与介电管式传感器(dielectric tube sensor,DTS)同腔共射的方法原位测定农田冰/水含量,NMM测量TSWC,DTS测量LSWC,两者的绝对差为SIC. 利用该方法在2011年至2012年冬天进行了测试。农田环境下同腔共射法在未冻土壤中的交叉检验结果表明:两种仪器具有良好的互换性(R2=0.950 3,RMSE=0.019 7 cm3·cm-3)。在冻土中的试验结果表明:该方法能够原位测定未冻水含量和总含水量,通过简单计算进而得到冻土含冰量。由于土壤冻融过程伴随着水分迁移,同腔共射法原位测定冻土冰/水含量显著提高了测量的准确性。获取的冻融信息不仅可为农田越冬期管理(尤其对确定冬灌和春耕时间)提供技术支持,且适用于农田尺度土壤剖面水分的常年监测。
关 键 词: 农业工程;土壤含冰量;土壤未冻水含量;土壤总含水量;PVC管;田间测定
Title: In situ measuring soil ice content with a combined use of dielectric tube sensor and neutron moisture meter in a common access tube
Author: CHENG Qiang, SUN Yurui, QIN Yulong, XUE Xuzhang, CAI Xiang, SHENG Wenyi, ZHAO Yandong
Organization: Key Laboratory of Agri-informatics Acquisition Technology, Ministry of Agriculture, China Agricultural University; National Engineering Research Center for Information Technology in Agriculture; School of Technology, Beijing Forestry University
Abstract: For monitoring soil water dynamics in cold regions, the major concerns are not only liquid soil water content (LSWC) and total soil water content (TSWC), but soil ice content (SIC) as well. The field determination of SIC is more challenging than that of LSWC or TSWC and no practical method has been found. This study presents a method that combined a neutron moisture meter (NMM) with a dielectric tube sensor (DTS) lowered in a common access PVC-tube, in which NMM was for determining TSWC and DTS was for LSWC. Consequently, the absolute difference was of SIC. The proposed method was tested in an agricultural field over the winter of 2011-2012. Field calibration and a cross-check showed that DTS and NMM measurements in the common access PVC-tube were very similar (R2=0.950 3, RMSE= 0.019 7 cm3穋m-3) to the volumetric soil water contents (VSWCs) ranging from 0.05 to 0.40 cm3穋m-3. More importantly, the results of overall experimental period confirmed that both sensors had the same responses in the unfrozen layers but different responses in the frozen layers. Based on this, we transformed the measurements of both sensors into SIC. Furthermore, for characterizing the SIC dynamics during the overall experimental period, we presented the curve-based results and the map-based results, respectively. These results verified that the proposed method is feasible to determine the SIC profiles in situ with a major advantage that allows both probes lowering multiple access PVC-tubes at the field scale.
Key words: agricultural engineering; soil ice content; liquid soil water content; total soil water content; PVC-tube; field determination
发表期数: 2016年2月第3期
引用格式: 程强,孙宇瑞,秦玉龙,等. 介电管式传感器与中子水分仪同腔共射原位测定农田冰/水含量[J]. 中国科技论文在线精品论文,2016,9(3):275-283.
 
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