Tensiometer

Tensiometer

A tensiometer is a device used to determine matric water potential Psi_m (soil moisture tension) in the vadose zone. The tensiometer consists of a glass or plastic tube with a porous ceramic cup, and is filled with water. The top of the tube has either a built-in vacuum gauge or a rubber cap used with a portable "puncture tensiometer" instrument, which uses a hypodermic needle to measure the pressure inside the tensiometer. The tensiometer is buried in the soil, and a hand pump is used to pull a partial vacuum. As water is pulled out of the soil by plants and evaporation, the vacuum inside the tube increases. As water is added to the soil, the vacuum inside the tube pulls moisture from the soil and decreases. The actual gauge reading will vary according to the type of soil, the moisture content, and due to hysteresis, according to the saturation history of the soil.

Tensiometers are used in irrigation scheduling to help farmers and other irrigation managers to determine when to water. In conjunction with a water retention curve, tensiometers can be used to determine how much to water. With practice, a tensiometer can be a useful tool for these purposes. Tensiometers can also be used in the scientific study of soils and plants.

References

* Rawls, W.J., Ahuja, L.R., Brakensiek, D.L., and Shirmohammadi, A. 1993. "Infiltration and soil water movement", in Maidment, D.R., Ed., Handbook of hydrology, New York, NY, USA, McGraw-Hill, p. 5.1–5.51.

ee also

*Capillary action
*Piezometer
*Surface tension

External links

* [http://www.experimental-hydrology.net/wiki/index.php?title=Soil_matric_potential_-_tensiometer_%28T4%29 The Experimental Hydrology Wiki Soil matric potential - tensiometer (T4)]
* [http://www.experimental-hydrology.net/wiki/index.php?title=Soil_matric_potential_-_tensiometer_%28T5%29 The Experimental Hydrology Wiki Soil matric potential - tensiometer (T5)]


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Look at other dictionaries:

  • Tensiometer — (vom lateinischen tensus spannen, straff anziehen) sind Messgeräte für Tensiometer (Oberflächenspannung), die Oberflächenspannung von Flüssigkeiten Tensiometer (Bodenfeuchte), die Feuchtigkeit im Boden die Bandzugkraft in Walzwerken …   Deutsch Wikipedia

  • tensiometer —  Tensiometer  Тензиометр   Прибор для измерения поверхностного или межфазного натяжения. Термин относится к приборам любой конструкции …   Толковый англо-русский словарь по нанотехнологии. - М.

  • tensiometer — [ten΄sē äm′ət ər] n. [< TENSION + METER] any instrument for measuring tautness or tension, as of a stretched wire or fabric or of the surface of a fluid …   English World dictionary

  • tensiometer — noun Etymology: tension Date: 1912 1. a device for measuring tension (as of structural material) 2. an instrument for determining the moisture content of soil 3. an instrument for measuring the surface tension of liquids • tensiometric adjective… …   New Collegiate Dictionary

  • tensiometer — /ten see om i teuhr/, n. 1. an instrument for measuring longitudinal stress in wires, structural beams, etc. 2. an instrument for measuring the surface tension of a liquid. [1910 15; TENSIO(N) + METER] * * * …   Universalium

  • tensiometer — noun a) An instrument used to measure the moisture content of soil b) An instrument used to measure the tension in a wire, or its tensile strength See Also: tensiometric, tensiometry …   Wiktionary

  • tensiometer — A device for measuring tension. [L. tensio, tension, + G. metron, measure] * * * ten·si·om·e·ter .ten(t) sē äm ət ər n 1) a device for measuring tension 2) an instrument for measuring the surface tension of liquids * * * ten·si·om·e·ter… …   Medical dictionary

  • Tensiometer — Тензиметр; Прибор для измерения (поверхностного) натяжения …   Краткий толковый словарь по полиграфии

  • Tensiometer — Ten|sio|me|ter 〈n. 13〉 Gerät zur Bestimmung der Oberflächenspannung …   Universal-Lexikon

  • tensiometer —    A device used to measure the moisture tension in the unsaturated zone [22] …   Lexicon of Cave and Karst Terminology

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