Irrometer, P-2001, Model "P" Portable Soil Water Tension Detector with 12" Extension Tip & Handle for Easy Removal
The IRROMETER Model “P” (Portable) was developed to assist the user in determining soil moisture status in temporary monitoring situations. The Instrument measures in centibars (cb) or kilopascals (kPa) of soil water tension. This value represents the energy a plant’s root system uses to draw water from the soil. Understanding soil moisture activity helps the user make informed irrigation scheduling decisions. Unlike other model IRROMETERs which are intended for permanent installation, the Model “P” is designed to be installed in a temporary situation so that the user can make a “spot check” of soil water tension and then relocate the instrument to other locations. Each site reading may take from minutes to hours, depending on soil conditions.
Includes:
- Reservoir
- Air-free gauge chamber
- Hermetically sealed Irrometer vacuum gauge with dual scale of centibars (cb) and kilopascals (kPa) [ 0-100 cb (kPa) range]
- Insertion handle
- 12 in. (30 cm) extension tip
Features:
- 0-100 cb (kPa) range gauge
- Air free gauge gives accurate readings
- Large reservoir makes maintenance easy
- Hermetically sealed gauge designed for harsh environments
- Chrome plated handle makes frequent installation and removal easy
Operating Principle
The IRROMETER operates on the tensiometer principle, which measures soil water tension. Soil water tension is the energy (vacuum) applied to soil by the plant as it draws in water for nutrition. This force is measuin centibars (cb) or kilopascals (kPa) of tension with a high reading indicating the dry end of the scale and a low reading indicating the wet end of the scale. The IRROMETER instrument consists of a sealed, fluid filled tube that is equipped with a porous ceramic tip and a special vacuum gauge. They are installed in the ground with the tips placed at desiroot zone depths. As the soil dries (increasing tension), fluid is drawn out of the instrument. This reduces the fluid volume in the IRROMETER, thus creating a partial vacuum which is registeon the gauge. The drier the soil, the higher the gauge reading. An irrigation application or rainfall event reverses this action. As water flows back into the soil (and the IRROMETER), tension is relieved in the soil and the instrument, resulting in a lower gauge reading (lower tension). In effect, the instrument is indicating how hard the roots are working. Due to IRROMETER's unique principle of operation, no calibrations are necessary under normal operating conditions for different soil types. A gauge reading of 50 cb (kPa) indicates that the roots are extracting the same amount of moisture whether the crop is planted in sandy soil or clay soil.
Applications
Consultants and other irrigation professionals find the Model “P” particularly useful because of its ability to gather soil moisture data from multiple non-permanent test site locations. The rugged T-handle clamped onto the instrument allows operators to easily insert and remove the instrument in most soils. For best results, the Model “P” should be used at a maximum depth of 18 in. (45 cm) in open porous soil. This nstrument is particularly useful in shallow rooted vegetables, nursery and greenhouse crops and containerized plants. Permanent installations of conventional model IRROMETERS (R, S, SR, LT, MLT) are always advisable, and provide for better long term management of irrigation.
Specification Information
The irrigation system shall incorporate soil moisture indicators to aid in making irrigation scheduling decisions. The soil moisture indicator shall operate on the tensiometer principle and indicate soil water tension, displaying in units of centibars (cb) or kilopascals (kPa). It shall have a hermetically sealed gauge that remains full of fluid even if the instrument tube is completely drained. Tube shall be constructed of durable plastic, that is impervious to attack by soil chemicals, with a ceramic sensing tip. It shall include a fluid reservoir with a submerged valve, whereby fluid can be drained into the tube by turning the cap. It shall be portable to facilitate measurements at different locations. All ceramic to plastic connections shall be guaranteed leak proof. The soil moisture indicator shall be an IRROMETER Model P as manufactuby the IRROMETER Company, Inc. of Riverside, California.
| Hermetically Sealed Gauge - Accuracy and long life are ensuby a hermetically sealed cover with a molded-in diaphragm which keeps dirt and moisture out and compensates for variations in temperature and barometric pressure. |  |
| Air-Free Gauge - The water seal prevents air from entering gauge, so gauge and chamber remain full regardless of water level in instrument. |
| The Irrometer Body - is constructed of tough durable plastic impervious to attack by soil chemicals or electrolysis. |
| Rugged Handle - makes installation and removal easy. |
| Closure - Large cap for easy operation and better control. Cap removes for filling reservoir. Submerged valve gives a positive leak proof seal. Servicing is instantaneous with a twist of the wrist. |
| Reservoir - holds a reserve supply of fluid sufficient for several irrigation cycles under average operating conditions. Unscrewing cap part way releases air and fills tube to replace fluid lost by the action of drying soil. |
| Ceramic to Plastic - connections are permanently leak proof. |
