Hanna Instruments HI 83900-30 - Manual (Page 5)

8 9
S AMPLE E XTRACTION
Warning! Never operate the lysimeter in the following conditions:
• immediately after irrigation, otherwise the extracted solution will be the
irrigation water and not the soil solution.
• before the irrigation water reaches the depth of the ceramic tip, because
necessary tension can never be obtained if the sensitive tip is dry.
• Sample extraction needs a vacuum of approxi-
mately -60 cb (centibar) to be created inside
the sampler tube. Connect the syringe to the
rubber capillary, open the finger clamp and
draw the syringe piston all the way back (30
mL). Pinch the finger clamp and disconnect
the syringe.
To obtain a vacuum of about -60 cb (cen-
tibar), perform these operations once with the
HI 83900-30 model, twice with HI 83900-
60 and 3 times with HI 83900-90.
• Before drawing out the soil solution, allow a
time interval which depends on the soil type.
Tuff or sandy soil: 30 minutes
Light soil:
1 hour
Medium soil: 2 to 4 hours
Heavy soil: 3 to 12 hours
• To collect the soil solution, connect the syringe to the rubber capillary, open the finger
clamp and the rubber cap, then draw the syringe piston all the way back (30 mL).
• Hold the piston until all the solution is sucked into the syringe, then disconnect the
syringe from the capillary and leave the finger clamp open.
• Transfer the soil solution into the sampling vessel and immediately perform tests.
• Never draw the syringe piston more than specified times, otherwise the
soil moisture tension will be broken. In addition, when a very high vacuum
is created at the soil solution, the test results will be unreliable, due to a
non-aerobic process.
• After drawing out the solution, the lysimeter should not remain at vacuum
conditions until the next time of operation.
SUGGESTIONS FOR SAMPLE ANALYSIS
HANNA instruments ® offers a wide variety of instrumentation, chemical test kits and
reagents (ask your dealer for details) to analyze soil solution samples.
Use the HI 83215 (or HI 83225) Grow Master bench photometer for testing the
presence and strength of ammonia, nitrate, phosphorus and potassium on
the spot (low, medium and high ranges). This advanced instrument is very
simple to operate even for non-technical users, and provides lab results.
1. Add the proper reagent (see photometer instruction manual) to the sample solu-
tion and shake gently.
2. Fill two measuring cuvets, one with the solution without reagent (blank) and the
other with the reacted sample. Screw the cap onto the cuvets and shake.
3. Wipe the cuvets with a soft tissue to remove any dirt or fingerprint.
4. Select the desired program and insert
the “blank” cuvet into the photometer
cell. Press “ZERO”.
5. Now insert the cuvet with the solution
to be analyzed and press “READ”.
For pH/EC/TDS measurements, you can use these portable meters, housed in a
water-resistant casing ideal for field applications:
HI 9811-5 0 to 14 pH, 6000 μS/cm, 3000 ppm, 0 to 70°C
HI 9813-6 0 to 14 pH, 4.00 mS/cm, 1999 ppm, 0 to 60°C, with HANNA F.S.T. system
HI 991300 0 to 14 pH, 3999 μS/cm, 2000 ppm, 0 to 60°C, with advanced features
Chemical Test Kits for Agriculture:
HI 38078 kit for SAR (Sodium Absorption Ratio) test
HI 3896 professional kit for testing traces, low, medium and high ranges of
nitrogen, phosphorus and potassium, and pH from 4 to 9.