Tensiometer

Here at Smart Farming Technologies, we have a high-quality tensiometer for sale. Contact us to find out all benefits of using our tensiometer and how it can help you tremendously with your farming business.

Tensiometer Diagram and Pictures


What Is A Tensiometer?

A tensiometer is an instrument used for measuring the moisture content of soil. It indicates the physical forces of gravity and molecular bonding that must be overcome in order to pull water out of the soil. The water held in the soil is known as the matrix water potential. A tensiometer is used to measure how easily water can be extracted out of the soil and to gauge how hard a plant is going to have to work to absorb water from its surrounding soil.

Tensiometers are very helpful to farmers in predicting how much water their crops are going to need. Knowing their irrigation requirements, farmers are able to set up irrigation schedules. They are able to assess more accurately how much water is needed by their crops and at what intervals they would need watering. This knowledge is particularly useful during the dry seasons. Tensiometers are also easily managed and can be automated to control irrigation.

A tensiometer usually is comprised of a long, sealed tube made of clear glass or plastic which is partially filled with water. A porous ceramic covering that allows water through is located on one end of the tube. The other end has a vacuum gauge that measures the pressure within the tube. Tensiometers range from 6 inches (15.24 cm) in length to around 4 feet (about 1.22 meters), although there are mini-tensiometers that measure matrix water potential at a depth of .5 inches (1.27 cm).

The ceramic tip of a tensiometer is inserted to the depth of the soil that is being monitored. The tube that is partially filled with water has a vacuum and if there has been rainfall or the soil is otherwise moist, the ceramic tip absorbs moisture from the soil and the vacuum in the tube becomes weaker. Conversely, if the soil is dry, water is drawn out of the tube into the soil, and the vacuum in the tube increases. The gauge measures the vacuum and registers its reading and in this manner, a tensiometer continually records changes in soil water.

Tensiometers typically have a restricted area of dependability. Their readings portray only the soil moisture in the small volume of soil surrounding the area in which it is planted, thus it cannot be counted on to give readings of an entire site. In addition, tensiometers generally do not perform as well in very dry or desert conditions as some amount of water needs to be present in the soil for the instrument to operate effectively.

Tensiometers for Sale

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Benefits of Using the Tensiometer

1) Increase in Crop:
Using the tensiometer enables optimal irrigation according to the plant’s needs and results in healthier plants and a significant increase in its yields and their quality.

2) Water Saving:
Accurate and precise irrigation using the tensiometer will reduce excess of surface water and their leakage into the groundwater.

3) Fertilizer Saving:
Water saving also leads to significant fertilizer saving when the fertilization is done through the irrigation system, thus reduces fertilizer leakage into the groundwater and helps to protect the environment.

4) Energy Saving:
When irrigating from water wells or rivers using electric pumps, irrigation according to the plant’s needs will reduce the irrigation time and respectively the duration of use of the pumps and subsequently result in significant energy saving.

5) Reducing Workforce Resources and Pesticide Use:
Accurate and precise irrigation will reduce excess of surface water and herbarium growth. Reduction in herbarium saves workforce, reduces the need of spraying pesticides as well as helps to protect the environment.

6) Identifying Emergency Situations in Real Time:
A real time information regarding significant shortage in water due to extreme weather prevents significant damage to the crop. This situation will be reflected in an abnormal high increase in the graph of tensiometer readings.

7) Identifying Irrigation System Malfunction in Real Time:
A controller malfunction due to lack of irrigation, partial irrigation or failure in the irrigation line due to pipe explosion, will be reflected in an abnormal high in the graph of tensiometer readings.

8) Preventing Soil Salinity Problems:
A high salt content in the soil solution reduces the plant’s ability to extract water from the soil, which will be reflected in a moderate to slow increase in the graph of tensiometer readings.

9) Preventing Soil Disease in the Plant:
Precise irrigation creates optimal ventilation in the root system and prevents the development of anaerobic bacteria. Soil disease or nematodes will be reflected in a constant decrease in the graph of tensiometer readings until it becomes nearly horizontal.

10) Preventing Plant Toxicity:
Excess irrigation causes a lack of ventilation and results in an increase of nitrites in the soil which are poisonous to the plant. Identifying nitrites is done by using a soil solution extractor with an adequate test kit. If an excess of nitrites was detected, it is highly recommended to adjust the irrigation interval, which will result in an additional water saving. Excess of nitrites will be reflected in a constant decrease in the graph of tensiometer readings until it becomes nearly horizontal.

Efficient irrigation scheduling can lead to a saving in water, fertilizers and improved yield and crop quality.

Technical Details About Tensiometers

Analog Electronic Tensiometers are made of durable plastic tubes filled with distilled water and contains high-quality porous ceramic caps, which enable superior sensitivity and quick response to water tension variation.

The electronic water tension sensor, which is connected to the tensiometer, is fully temperature-compensated and made of high-quality materials. The output of the sensor is 4-20mA.

The standard lengths are 20 & 40cm depths, but 60cm depth is also available on special request.

  • The GSM Logger Alarm System consists of:
  • 6 analog inputs, 4-20mA, adapted to the tensiometers.
  • 2 special inputs for soil and air temperature sensors.
  • A low-power data logger, which is remote-controlled and programmed through cellular phone by SMS.
  • A cellular modem supporting GSM technology that transmits the collected data to the internet server by SMS messages at desired intervals.
  • A sim card holder.
  • Power supply is 1.5V – 8 AA alkaline batteries. In normal operating conditions, one set of good quality batteries should last for at least a whole season.
  • The shield case and all the connectors meet the waterproofing standard of IP-67.

The web-based monitoring center includes a central server that collects and stores all the data from field stations and presents it to an authorized user. All users purchase an initial one-year service package and thereafter have to renew the service once a year. The SIM card is also purchased once-off from a local cellular phone dealer.


Get your tensiometer today. Contact us to buy your tensiometer or for more information.