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פותח על ידי קלירמאש פתרונות בע"מ -
Horizontal and Vertical TDR Measurements of Soil Water Content and Electrical Conductivity
Year:
2002
Authors :
נדלר, אריה
;
.
Volume :
66
Co-Authors:

S. R. Green, I. Vogeler and B. E. Clothier - Environmental group, HortResearch, Private bag 11-030 Palmerston North, New Zealand 

Zealand

Facilitators :
From page:
735
To page:
743
(
Total pages:
9
)
Abstract:

When time domain reflectometry (TDR) is used to measure soil water content (θ) and salinity, the probes can be installed either horizontally or vertically. We tested the common convention that θ values averaged from horizontal probes will be equal to a vertical direct measurement. In a laboratory experiment, a sandy loam soil, packed uniformly (0.02‐m layers to 0.18‐m depth) into a box, was gradually wetted to saturation by CaCl2 solutions of 0, 0.5, 1.1, 2.1, 3.1, 4.5, 5.9, and 8.4 dS m−1 Horizontal and vertical TDR probes for measuring θ and electrical conductivity of the bulk soil (σa) were installed during soil packing. A comparison between θ values averaged from three horizontal probes and from two vertical ones showed deviations of 0.02 (L L−1). A simple water redistribution model was used to attribute this deviation to the process of averaging the horizontal results. The best practical attainable reproducibility, under our experimental conditions, were close to the theoretical limit 0.005 (L L−1) but the average experimental reproducibility of θ was 0.01 to 0.02 (L L−1). Width of the soil layer affecting the moisture measurement was reconfirmed to be close to 30 mm. The resistors‐in‐series model was found to be a good approximation to describe the soil profile σa from separately measured horizontal σa Final values of the electrical conductivity of the soil solution (σw) after sufficient leaching were in good agreement with σw values calculated by an empirical protocol that uses σa, θ, and a soil texture property.

Note:
Related Files :
Electrical conductivity
measurement
soil
Soil water content
TDR, Time domain reflectometry
water
עוד תגיות
תוכן קשור
More details
DOI :
https://doi.org/10.2136/sssaj2002.7350
Article number:
0
Affiliations:
Database:
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
50621
Last updated date:
02/03/2022 17:27
Creation date:
30/09/2020 15:48
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Scientific Publication
Horizontal and Vertical TDR Measurements of Soil Water Content and Electrical Conductivity
66

S. R. Green, I. Vogeler and B. E. Clothier - Environmental group, HortResearch, Private bag 11-030 Palmerston North, New Zealand 

Zealand

Horizontal and Vertical TDR Measurements of Soil Water Content and Electrical Conductivity

When time domain reflectometry (TDR) is used to measure soil water content (θ) and salinity, the probes can be installed either horizontally or vertically. We tested the common convention that θ values averaged from horizontal probes will be equal to a vertical direct measurement. In a laboratory experiment, a sandy loam soil, packed uniformly (0.02‐m layers to 0.18‐m depth) into a box, was gradually wetted to saturation by CaCl2 solutions of 0, 0.5, 1.1, 2.1, 3.1, 4.5, 5.9, and 8.4 dS m−1 Horizontal and vertical TDR probes for measuring θ and electrical conductivity of the bulk soil (σa) were installed during soil packing. A comparison between θ values averaged from three horizontal probes and from two vertical ones showed deviations of 0.02 (L L−1). A simple water redistribution model was used to attribute this deviation to the process of averaging the horizontal results. The best practical attainable reproducibility, under our experimental conditions, were close to the theoretical limit 0.005 (L L−1) but the average experimental reproducibility of θ was 0.01 to 0.02 (L L−1). Width of the soil layer affecting the moisture measurement was reconfirmed to be close to 30 mm. The resistors‐in‐series model was found to be a good approximation to describe the soil profile σa from separately measured horizontal σa Final values of the electrical conductivity of the soil solution (σw) after sufficient leaching were in good agreement with σw values calculated by an empirical protocol that uses σa, θ, and a soil texture property.

Scientific Publication
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