Hanna Instruments HI 83900-30 - Manual (Page 6)

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TROUBLESHOOTING
If the lysimeter is unable to extract soil solution, first check that:
• The soil is tightly in contact with the porous ceramic cap.
>>> Compress the surrounding soil if necessary.
• The suction capillary reaches the ceramic tip.
>>> Otherwise push it downwards through the rubber cap.
Moreover, the following conditions can cause inability to extract soil solution:
• The water has not reached the ceramic tip. This can occurs when the lysimeter is
positioned at a depth of 40-50 cm.
>>> Delay time of operation.
• Water reaches the depth of the ceramic tip very slowly, also measured in days for
very heavy or compact soils. In this case, the lysimeter should not be installed in
low depths such as 50-60 cm.
>>> Use the lysimeter in depths of only 15-30 cm.
>>> Install the lysimeter in a different location, where the soil is not
too compact.
• Fully developed plants can compete with the lysimeter for water, and may be not
possible to extract the solution. It can also happen that the solution not collected in
time will be extracted back from the lysimeter by the plant.
>>> Operate earlier.
• The water distribution is not uniform.
>>> Check the irrigation water flow.
• The soil is dry, due to an irrigation with insufficient amount of water.
>>> Irrigate again increasing the amount of water.
MAINTENANCE AND STORAGE
The lysimeter should remain installed for all the crop season, and the ceramic cap
must be sterilized against fungi and algae at least every two months, without remov-
ing it from the ground.
• Fill the syringe with the supplied cleaning solution (approximately 10 mL).
• With the finger clamp open, inject the solution into the lysimeter tube for about 10
seconds. Draw up the rest of the solution and dispose of it.
Do not perform soil solution tests immediately after sterilization.
In seasonal cropping and during winter, remove the lysimeter from its installation
before the first frost.
• Immediately after removing the lysimeter, immerse the tip in the cleaning solution
over night.
• Let the solution drain through the porous ceramic cap, gravity flow.
• Air dry the lysimeter and store it.
Warning!
• Do not let the ceramic cap dry while dirty.
• Do not store at temperatures below freezing because some water may
remain trapped inside the porous ceramic.