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    • Lysimetry Basics: Peering in to the Black Box Virtual Seminar Questions
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      • HYPROP
      • HYPROP-FIT Software
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Water Potential Instruments

  • Measurements:
    • Soil Suction,
    • Water Potential
  • Overview
  • Comparisons
  • Support
  • Education

Water potential describes the force that drives water movement. It is the most fundamental and essential measurement in soil physics.

Unfortunately, it's also a tricky thing to measure. The chart on the right (click on it to view the full image) shows range and accuracy for available instruments and sensors. You can find more information about each instrument's advantages and limitations on the individual product pages. For more information on water potential theory, see the resources list on the right.

wp4c2 Guide2WPunits.jpg

Comparisons

Support

Material Safety Data Sheet

  • MSDS 0.5m KCl
  • MSDS 6.0m NaCl
  • MSDS Activated Charcoal
  • MSDS Decagon Cleaning Solution
  • MSDS Distilled Water
  • MSDS Indicating Drierite
  • MSDS 8.57m LiCl
  • MSDS 13.41m LiCl
  • Material Safety Data Sheets

Application Notes

  • Classification of Expansive Soils using the WP4C Dewpoint Water PotentaMeter
  • Determining the -15 Bar (Permanent Wilt) Water Content of Soils with the WP4
  • Effects of Sample Disturbance on Soil Water Potential Measurements
  • Field Portability for the WP4C PotentiaMeter
  • Generating a Soil Moistures Characteristic Using the WP4C
  • Isotherm Analysis: New (and Old) Ways to Look at Soil
  • Measurement of Leaf Water Potential using the WP4C
  • Modeling Available Soil Moisture
  • Application Note: Seed Longevity in Storage is Enhanced by Controlling Water Activity

How-To Articles

  • Generating a Soil Moistures Characteristic Using the WP4C
  • Measurement of Leaf Water Potential using the WP4C

Manuals

  • Manual WP4
  • Manual-AquaSorp Isotherm Generator

Information Sheet

  • AquaSorp Information Sheet
  • Hyprop Information Sheet
  • WP4 Information Sheet

Request Support

Email: support@decagon.com
Phone: 800-755-2751 or
509-332-2756
Fax: 509-332-5158

Education

Newsletters

  • Water Potential Theory
  • Geoenvironmental Engineering Newsletter-2007
  • Soils News-1999
  • Soils News-2004
  • Soils News-2005
  • Soils News-2006
  • Soils News-2008
  • Soil & Plant Water Potential Newsletter 2011-2012

Virtual Seminar

  • January 25, 2011: Virtual Seminar: Measurements and Models for Macropore Infiltration in Soil
  • December 10, 2010: Virtual Seminar: Accurate and Reliable Soil Moisture Characteristic Curves (Moisture Release Curves) using Vapor Pressure Methods
  • September 28, 2010: Virtual Seminar: Quick Methods for Determining Plant Available Water
  • Virtual Seminar: Water Potential 201 - Choosing the Right Instrument

Newsletter Articles

  • January 11, 2007: Measuring Specific Surface of Soil with the WP4C
  • Newsletter-Field Capacity Is Not Saturation
  • Newsletter-Measuring Soil Water Potential - One Hundred Years of Progress
  • June 14, 2012: Newsletter-The Wilting Coefficient and Its Relation to Soil Water Content and Potential

List of Cited Publications

  • Cited Publications-WP4
  • Cited Publications - WP4 2008
  • Cited Publications - WP4 2007
  • Cited Publications - WP4 2006
  • Cited Publications - WP4 2005
  • Cited Publications - WP4 2004
  • Cited Publications - WP4 2002 - 2003

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Related Products or Services

  • HYPROP
  • MPS-1 Dielectric water potential sensor
  • Water Potential Sensors
  • Tensiometers
HYPROP.jpg

HYPROP

Generate detailed moisture release curves on undisturbed soil samples in a standard 250 mL sample ring, typically within a few days. Range: 0 to -85 kPa. HYPROP also determines unsaturated hydraulic conductivity values for the soil sample. » Learn more

d3

HYPROP-FIT Software

Curve fits for all water potential data. New HYPROP-FIT Software for generating soil moisture release curves. » Learn more

VSA-Ag1.png

Vapor Sorption Analyzer

The Vapor Sorption Analyzer (VSA) brings click and read efficiency to soil water characteristic curves. In 24 to 48 hours, the VSA generates up to 200 data points (water potential vs. water content) for both adsorption and desorption. The VSA works in the dry (-10 to -475 MPa) range. You can create automated soil-water characteristic curves and generate all the correlations with clay activity, surface area, and swelling potential. With the new static feature, you can hold humidity constant and look at the way soil takes up water into its crystal structure (2:1 clays) and monitor water content change over time. » Learn more

WP4C-cutout.jpg

WP4C Dewpoint Potentiameter

Fast, Accurate Water Potential Measurements Use the WP4C to measure water potential in 5 to 10 minutes.  Range: -0.1 to -300 MPa* </p> Versatile The WP4C can be used to measure the water potential of any porous material.  It's… » Learn more

AquaLink4CD

AquaLink Software

New AquaLink Software Traditionally, WP4C data storage and download have been a hassle. The WP4C saves data internally, but you had to keep track of the order in which you read the samples to make sure that the right sample was associated with the right reading.  Most people found it easier to… » Learn more

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