IN SITU MEASUREMENT OF NITRATE CONCENTRATION USING TIME DOMAIN REFLECTOMETRY

2006 ◽  
Author(s):  
M Krishnapillai ◽  
R Sri Ranjan
Keyword(s):  
Time Domain ◽  
Nitrate Concentration ◽  
Time Domain Reflectometry ◽  
In Situ Measurement

Measuring transient solute transport through the vadoze zone using time domain reflectometry

Soil Research ◽  
2001 ◽  
Vol 39 (6) ◽  
pp. 1359 ◽  
Author(s):  
I. Vogeler ◽  
S. Green ◽  
A. Nadler ◽  
C. Duwig
Keyword(s):  
Electrical Conductivity ◽  
Solute Transport ◽  
Time Domain ◽  
Deterministic Model ◽  
Soil Surface ◽  
Time Domain Reflectometry ◽  
Richards Equation ◽  
Electrical Conductivities ◽  
Destructive Measurement

Time domain reflectometry (TDR) was used to monitor the transport of conservative tracers in the field under transient water flow in a controlled experiment under a kiwifruit vine. A mixed pulse of chloride and bromide was applied to the soil surface of a 16 m2 plot that had been isolated from the surrounding orchard soil. The movement of this solute pulse was monitored by TDR. A total of 63 TDR probes were installed into the plot for daily measurements of both the volumetric water content (θ) and the bulk soil electrical conductivity (σa). These TDR-measured σa were converted into pore water electrical conductivities (σw) and solute concentrations using various θ–σa–σw relationships that were established in the laboratory on repacked soil. The depth-wise field TDR measurements were compared with destructive measurement of the solute concentrations at the end of the experiment. These results were also compared with predictions using a deterministic model of water and solute transport based on Richards’ equation, and the convection–dispersion equation. TDR was found to give a good indication of the shape of the solute profile with depth, but the concentration of solute was under- or over-estimated by up to 50%, depending on the θ–σa–σw relationships used. Thus TDR can be used to monitor in situ transport of contaminants. However, only rough estimates of the electrical conductivity of the soil solution can so far be obtained by TDR.

An Innovative Use of TDR Probes: First Numerical Validations with a Coaxial Cable

2018 ◽  
Vol 23 (4) ◽  
pp. 437-442
Author(s):  
Raffaele Persico ◽  
Iman Farhat ◽  
Lourdes Farrugia ◽  
Sebastiano D'Amico ◽  
Charles Sammut
Keyword(s):  
Magnetic Properties ◽  
Transmission Line ◽  
Time Domain ◽  
Numerical Data ◽  
Time Domain Reflectometry ◽  
Coaxial Cable ◽  
Transmission Line Model ◽  
Properties Of Materials

In this paper we propose a study regarding some possibilities that can be offered by a time domain reflectometry (TDR) probe in retrieving both dielectric and magnetic properties of materials. This technique can be of interest for several applications, among which the characterization of soil in some situations. In particular, here we propose an extension of the paper “Retrieving electric and magnetic propetries of the soil in situ: New possibilities”, presented at the IWAGPR, held in Edinburgh in 2017, and as a new contribution we will validate a transmission line model with numerical data simulated by the CST code.

Thermo–time domain reflectometry method: Advances in monitoring in situ soil bulk density

2020 ◽  
Vol 84 (5) ◽  
pp. 1354-1360
Author(s):  
Yili Lu ◽  
Xiaona Liu ◽  
Meng Zhang ◽  
Joshua Heitman ◽  
Robert Horton ◽  
...  
Keyword(s):  
Bulk Density ◽  
Time Domain ◽  
Soil Bulk Density ◽  
Time Domain Reflectometry

In situ measurement of snowmelt infiltration under various topsoil cap thicknesses on a reclaimed site

2013 ◽  
Vol 93 (4) ◽  
pp. 497-510 ◽  
Author(s):  
Andre F. Christensen ◽  
Hailong He ◽  
Miles F. Dyck ◽  
E. Lenore Turner ◽  
David S. Chanasyk ◽  
...  
Keyword(s):  
Effective Permittivity ◽  
Water Flux ◽  
Climatic Conditions ◽  
Time Domain Reflectometry ◽  
In Situ Measurement ◽  
Water Dynamics ◽  
Soil Freezing ◽  
Weather Data ◽  
Freezing And Thawing

Christensen, A. F., He, H., Dyck, M. F., Turner, L., Chanasyk, D. S., Naeth, M. A. and Nichol, C. 2013. In situ measurement of snowmelt infiltration under various topsoil cap thicknesses on a reclaimed site. Can. J. Soil Sci. 93: 497–510. Understanding the soil and climatic conditions affecting the partitioning of snowmelt to runoff and infiltration during spring snow ablation is a requisite for water resources management and environmental risk assessment in cold semi-arid regions. Soil freezing and thawing processes, snowmelt runoff or infiltration into seasonally frozen soils have been documented for natural, agricultural or forested systems but rarely studied in severely disturbed systems such as reclaimed lands. The objective of this study was to quantify the snowmelt infiltration/runoff on phosphogypsum (PG) tailings piles capped with varying thicknesses of topsoil (0.15, 0.3, and 0.46 m) at a phosphate fertilizer production facility in Alberta. There are currently no environmental regulations specifying topsoil capping thickness or characteristics for these types of tailings piles. Generally, the function of the topsoil cap is to facilitate plant growth and minimize the amount of drainage into the underlying PG. Experimental plots were established in 2006 to better understand the vegetation and water dynamics in this reconstructed soil. In 2011, time domain reflectometry (TDR) probes and temperature sensors were installed at various depths for continuous, simultaneous, and automated measurement of composite dielectric permittivity (ɛeff) and soil temperature, respectively. An on-site meteorological station was used to record routine weather data. Liquid water and ice content were calculated with TDR-measured effective permittivity (ɛeff) and a composite dielectric mixing model. Spatial and temporal change of total water content (ice and liquid) revealed that snowmelt infiltration into the topsoil cap increased with increasing topsoil depth and net soil water flux from the topsoil cap into the PG material was positive during the snowmelt period in the spring of 2011. Given the objective of the capping soil is to reduce drainage of water into the PG material it is recognized that a capping soil with a higher water-holding capacity could reduce the amount of meteoric water entering the tailings.

Thermo–Time Domain Reflectometry Method: Advances in Monitoring In Situ Soil Bulk Density

2017 ◽  
Vol 2 (1) ◽  
pp. 0 ◽  
Author(s):  
Yili Lu ◽  
Xiaona Liu ◽  
Meng Zhang ◽  
Joshua Heitman ◽  
Robert Horton ◽  
...  
Keyword(s):  
Bulk Density ◽  
Time Domain ◽  
Soil Bulk Density ◽  
Time Domain Reflectometry
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