Vidana Gamage Duminda N, Biswas Asim, Strachan Ian B, Adamchuk Viacheslav I
Department of Natural Resource Sciences, McGill University, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada.
School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada.
Sensors (Basel). 2018 Apr 6;18(4):1116. doi: 10.3390/s18041116.
Several studies have demonstrated the potential of actively heated fiber optics (AHFO) to measure soil water content (SWC) at high spatial and temporal resolutions. This study tested the feasibility of the AHFO technique to measure soil water in the surface soil of a crop grown field over a growing season using an in-situ calibration approach. Heat pulses of five minutes duration were applied at a rate of 7.28 W m along eighteen fiber optic cable transects installed at three depths (0.05, 0.10 and 0.20 m) at six-hour intervals. Cumulative temperature increase during heat pulses was calculated at locations along the cable. While predicting commercial sensor measurements, the AHFO showed root mean square errors (RMSE) of 2.8, 3.7 and 3.7% for 0.05, 0.10 and 0.20 m depths, respectively. Further, the coefficients of determination (R²) for depth specific relationships were 0.87 (0.05 m depth), 0.46 (0.10 m depth), 0.86 (0.20 m depth) and 0.66 (all depths combined). This study showed a great potential of the AHFO technique to measure soil water at high spatial resolutions (<1 m) and to monitor soil water dynamics of surface soil in a crop grown field over a cropping season with a reasonable compromise between accuracy and practicality.
多项研究已证明主动加热光纤（AHFO）在高空间和时间分辨率下测量土壤含水量（SWC）的潜力。本研究采用原位校准方法，测试了AHFO技术在作物生长季节测量作物种植田表层土壤水分的可行性。沿着安装在三个深度（0.05、0.10和0.20米）的18条光纤电缆样带，以7.28 W/m的功率每隔6小时施加持续5分钟的热脉冲。计算电缆沿线各位置热脉冲期间的累积温度升高。在预测商业传感器测量值时，AHFO在0.05、0.10和0.20米深度处的均方根误差（RMSE）分别为2.8%、3.7%和3.7%。此外，特定深度关系的决定系数（R²）分别为0.87（0.05米深度）、0.46（0.10米深度）、0.86（0.20米深度）和0.66（所有深度综合）。本研究表明，AHFO技术在高空间分辨率（<1米）下测量土壤水分以及在作物生长季节监测作物种植田表层土壤水分动态方面具有巨大潜力，在准确性和实用性之间取得了合理的平衡。
