Soil moisture by tensiometer. for more infomation and getting in ppt formate visite nikunjchauhan.com

1. Nikunj Chauhan
Roll No : 19
Exam No : 05-0254-2014
College of Agricultural Engineering
and Technology

2. Really all Crops Need Water ?
Soil Moisture
No, They Don't
but

3. Some instruments
◦Tensiometer
◦Digital soil moisture meter
◦TDR Moisture meter
◦FDR moisture meter
◦Neutron probe moisture meter
Seminar on Soil moisture by
Tensiometer

4. Content
Introduction
Working
Unit of measurement
Data
Uses
Advantages and Disadvantages

5. Tensiometer directly measure
A Tensiometer is measuring
instrument used to determine the soil
moisture in the Crop Root zone.
Tensiometer
Vacuum Gauge
Porous Ceramic cup
Water Tube
Cap
Soil moisture ∝ 1
Soil metric potential
Soil metric potential

6. Working
◦Fully fill the Tensiometer
with water.
◦Placed the Tensiometer in
field such that ceramic cup
in contact with the soil.

7. Working
◦Unsaturated Condition in
soil
◦Saturated Condition
Water moves from
Tensiometer to soil
Soil
Ceramic
tip

8. Working
◦Water level Reduces
◦Amount of Water Removed
generate vacuum.

9. Working
◦Vacuum causes a
reading on the vacuum
gauge
0 indicates that the
soil is saturated
50+ indicates that the
soil is dry
◦Movement of water will
stop at equilibrium
condition

10. Working
Soil
Soil moisture

11. Unit of Measurement
Readings
• kilopascals
•Bars or Centibars
``

12. Tensiometer reading
Readings
(kPa)
Soil moisture ( %) (dry basis)
Clay soil Sandy soil
0 58 32
20 30 10
40 23 8
60 20 7
80 18 6
Source: General guideline notes by SKYE
INSTRUMENTS LIMITED

13. Tensiometer reading
clay soil
sandy soil
Tensiometer reading ( kPa)
Soilmoisture(%)

14. Source of Error
◦Air enters in tube.
◦Faulty Vacuum gauge
◦Bad contact with soil
◦Readings more then 80kPa
◦Leakage of water from tube

15. Uses
Irrigation
Scheduling
Research
Purpose
Intelligent
irrigation
system

16. Advantages of Tensiometer
◦It gives fast Result
◦Essay to operate and Carry
◦High Accuracy
◦Low Cost
◦Large Sensing Area
◦Not affected by salinity of soil

17. Disadvantages of Tensiometer
◦Required Periodic service
◦Limited range
◦Not useful in dry soil

18. Website
Nikunjchauhan.com
Thank you
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Feedback & Questions
Reference ( Research paper )
Tensiometers for Soil Moisture
Measurement and Irrigation Scheduling By
Allen G. Smajstrla and Dalton S. Harrison