Measurement of Potassium in Rice

Potassium is one of the essential plant nutrients supplied via fertilizer in most irrigated rice fields. Extracting sap from the lower stem of plant rice and analysing it with LAQUAtwin potassium meter provide indication of the current potassium status and help farmers adjust the fertilizer application.


Potassium is a necessary nutrient for soil in which rice grain is grown, as it is critical in maximising yield.

In order to profitably produce rice, reliable information regarding the potassium content of the soil must be available to farmers. Thus, we can analyse the potassium content of the plant tissue in the roots of the rice grain.

To determine the potassium content, the Horiba LAQUAtwin K-11 potassium ion (K+) meter can be used. This is an easy and quick method used to determine the potassium content of soil for the growth of rice crops.


  1. The above ground portion of the crop is separated from the root using shears.
  2. The lower stem is washed of soil.
  3. The stem is cut into 1 cm pieces.
  4. The pieces of stem are frozen overnight.
  5. A frozen piece of stem is placed in a sap press to obtain the sap.
  6. A small sample of the sap is placed on the sensor of the LAQUAtwin K-11 meter and the potassium content is measured after one minute.
  7. To repeat sampling, wash the sensor with tap  water and pat dry with a paper tissue.

Results and Benefits

The use of the Horiba LAQUAtwin K-11 meter to measure the potassium content of soil around rice crops will improve farmers’ knowledge of the potassium accumulation. Accordingly, farmers can fertilise their crops with optimal amounts of potassium.

The LAQUAtwin K-11 meter is small and compact, and convenient to carry for easy on-site testing. Its easy-to-use interface is simple for anyone to use.

David Dunn, Gene Stevens “Plant Mapping Potassium in Rice Tissue: What Part to Sample When?: Second Year (2004) Progress report” University of Missouri-Delta Center

LAQUAtwin: the only meters with flat sensor technology.

HORIBA’s highly-sensitive, flat sensor technology opens up new possibilities for sampling and sample types. Only a small amount of sample is required, so you can easily sample in situ without the need for beakers or other labware. Sensors are easily replaced as required.

Calibrate and measure at the touch of a button — the smiley face will tell you when the result can be read.

Hassle-free automatic calibration with a few drops of standard solution reassures you of your measurement accuracy. Two-point calibration is also possible.*
*Except for B-711

LAQUAtwin is fully waterproof and dustproof.

The meter and sensor are fully waterproof* and dustproof, so you can take it anywhere.
* IP67 rated. Will withstand immersion for 30 minutes at 1 m. Not suitable for underwater use.

Carry case comes as standard for handy portability.

The compact carry case contains everything you need for your measurements, including the standard solution and sampling sheets.

Matching products

Horiba LAQUAtwin Potassium Ion (K+) Tester with 2 calibration points and temperature measurement (K-11)
Product number: 895658
Measuring range: 4 to 9900 ppm (mg/L) - (0.1 to 250 mmol/L) | 2 to 5000 kg/10a (soil/water ratio 1:5) | 0 to 50.0 ºC | Measurement parameters: Potassium Ion | Temperature
Manufacturer Part No. 3200689160 LAQUAtwin KA-11 : The world's first pocket-sized potassium ion analyser. Your mobile laboratory - for use on site: Ideal for water quality testing in agriculture, food and many other applications. HORIBA's unique compact meter integrates electrode, display and sample container to enable simple, effective on-site testing by direct measurement with a single drop.         Minimum sample volume: 0.3 ml (0.05 ml with sampling sheet B)        Up to 2 calibration points        Automatic standard detection: 150 & 2000 ppm potassium (standard)        Adjustable high and low calibration values        Multiplication compensation: 0.01 to 9.90        Temperature and mV display        Temperature calibration: 5 to 40.0 ºC        Auto Hold / Auto Stable measurement        Automatic switch-off: 30 min.        Low battery indicator        IP67 protection class, dust and waterproof        Replaceable sensor        400 hours battery life: continuous operation without backlight        Material: ABS epoxy resin        Display: user-defined (monochrome) digital LCD with backlight        Operating conditions: 5 to 40 ºC, 85% or less relative humidity        Warranty: 2 years - meter, 6 months - sensor        Packed in practical carrying case Supplied with 150 and 2000 ppm potassium standards, 5 x sampling sheets B, 2 x CR2032 batteries, pipette, user manual and quick reference guides

Horiba 4M LAQUAtwin Kit with Sodium, Potassium, Nitrate and Calcium Ion Tester
Product number: 895690
Measuring range: see technical data | Measurement parameters: Sodium ions | Potassium ions | Nitrate ions | Calcium ions | Temperature
With the HORIBA 4M LAQUAtwin Kit you get a high-quality mobile laboratory for your analyses.The high-quality case contains the well-known ion selectives "Made in Japan" LAQUAtwin Pocket Tester for sodium, potassium, nitrate and calcium determination and offers you a price advantage, as you receive the case including accessories free of charge compared to a single purchase. The lid of the case itself contains a storage box for the colour-sorted calibration solutions included in the scope of delivery, as well as a wash / spray bottle for easy cleaning of the sensors.The case itself can hold up to seven HORIBA LAQUAtwin Pocket Testers, so simply add the additional testers you want to the shopping basket and we will take care of everything else.As usual, the manufacturer provides a two-year warranty and the devices offer the advantage that the sensors can be stored dry and you do not need any storage solutions.Do you have any questions? Please feel free to call us!Manufacturer Part No. 1300083234