Averaging water content and electrical conductivity of a layered soil using time domain reflectmetry...
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Transcript of Averaging water content and electrical conductivity of a layered soil using time domain reflectmetry...
Averaging water content and electrical conductivity of a layered soil using time domain reflectmetry
Hiroyuki Ochiai, and Kosuke Noborio
School of Agriculture, Meiji University, Japan
People use TDR probes vertically and horizontally People use TDR probes vertically and horizontally installed.installed. However there is a little of research on However there is a little of research on vertical TDR probes taking an average of vertical TDR probes taking an average of water content () and and electrical conductivity (EC) with layers. In EC) with layers. In this study, averaging EC is shown.this study, averaging EC is shown.
Objective
・ Topp et al. (1980, 1982) developed the Time Domain Reflectmetry (TDR) method for measuring soil water content ().
・ Topp and Davis (1984) studied measuring q at the field by TDR.
・ Kachanoski et al. (1990) were using TDR probes by vertically insert.
・ Nadler et al. (1991) studied measuring electrical conductivity by TDR method.
Background
Material
TDR probe for vertical(80mm)
80mm80mm
Column with TDR probeColumn with TDR probe
i.d.=76.5mm h=20mm
Research
Type1. Same water content and different concentration in each columns
Type2. Different water content and same concentration in each columns
Type3. Different water content and different concentration in each columns
Steady Water Content and Different Concentration
0 20 40 60 80
1
2
3
4
5
EC(S/ m)
vertical averagehorizontal averate
Results and Discussion
Type1
1. Similar concentration in 3yayers1. Similar concentration in 3yayers
vertical = horizontalvertical = horizontal
2. Highest concentration in the highest column2. Highest concentration in the highest column
vertical > horizontalvertical > horizontal
3. Highest concentration in the lowest column3. Highest concentration in the lowest column
vertical > horizontalvertical > horizontal
4. Lowest concentration in the middle column4. Lowest concentration in the middle column
vertical > horizontalvertical > horizontal
5. Highest concentration in the middle column 5. Highest concentration in the middle column
vertical < horizontalvertical < horizontal
Type2
Dfferent Water Content and Steady Concentration
0 20 40 60 80
6
7
8
9
10
EC(S/m) vertical averagehorizontal average
6. Similar 6. Similar in 3yayers in 3yayers
vertical = horizontalvertical = horizontal
7. Highest 7. Highest in the middle column in the middle column
vertical < horizontalvertical < horizontal
8. Highest 8. Highest in the highest column and middle is the lowest in the highest column and middle is the lowest
vertical < horizontalvertical < horizontal
9. Highest 9. Highest in the lowest column and middle is the lowest in the lowest column and middle is the lowest
vertical < horizontalvertical < horizontal
10. higher 10. higher in the higher column in the higher column
vertical > horizontalvertical > horizontal
Type1
Type2
Type3
Type311. Highest concentration in the highest column and the highest 11. Highest concentration in the highest column and the highest
in the middle columnin the middle column
vertical > horizontalvertical > horizontal
12. Highest concentration in the highest column and the highest 12. Highest concentration in the highest column and the highest in the lowest columnin the lowest column
vertical < horizontalvertical < horizontal
13. Highest concentration in the lowest column and the highest 13. Highest concentration in the lowest column and the highest in the highest columnin the highest column
vertical > horizontalvertical > horizontal
14. Highest concentration in the lowest column and the lowest 14. Highest concentration in the lowest column and the lowest in in the highest columnthe highest column
vertical > horizontalvertical > horizontal
15. Highest concentration in the lowest column and the lowest 15. Highest concentration in the lowest column and the lowest in in the middle columnthe middle column
vertical > horizontalvertical > horizontal
16. Highest concentration in the middle column and the lowest 16. Highest concentration in the middle column and the lowest in the lowest columnin the lowest column
vertical < horizontalvertical < horizontal
17. Highest concentration in the middle column and the lowest 17. Highest concentration in the middle column and the lowest in the middle columnin the middle column
vertical < horizontalvertical < horizontal
Conclusions
Average data of Average data of vertical probesvertical probes
Average data of Average data of horizontal probeshorizontal probes
==
・・ When mass of KCl in the top or bottom column is the highesWhen mass of KCl in the top or bottom column is the highest,t,Average data of Average data of
vertical probesvertical probesAverage data of Average data of
horizontal probeshorizontal probes>>
Average data of Average data of vertical probesvertical probes
Average data of Average data of horizontal probeshorizontal probes
>>
・・ When mass of KCl in the middle column is the lowest,When mass of KCl in the middle column is the lowest,
・・ When mass of KCl in the middle column is the highest,When mass of KCl in the middle column is the highest,
・・ When mass of KCl in 3 columns is the same,When mass of KCl in 3 columns is the same,
Average data of Average data of vertical probesvertical probes
Average data of Average data of horizontal probeshorizontal probes
<<
Note
Win TDR sometimes did not work because the form between t1 and t2 is wavy. Therefore, it did not proceed to obtain an EC value.
- 0.20
- 0.10
0.00
0.10
0.20
0.30
0.40
0.50
t1t1 t2t2
Different Water Content and Different Concentration
0 20 40 60 80
11
12
13
14
15
16
17
EC(S/ m)
vertical averagehorizontal average
・・ Ratio differences of mass KCl in each columns effect on incrRatio differences of mass KCl in each columns effect on increasing differences of average data between vertically and easing differences of average data between vertically and horizontally.horizontally.
acknowledgement
This study is carried out as a part of “Ground – based Research Announcement for Space Utilization” promoted by Japan Space Forum