Quick and easy determination of the -15 bar (permanent wilt) water content of soils with the WP4C

The WP4C and other similar vapor pressure instruments provide the only reliable means for obtaining the -1.5 MPa water content of a sample.

Why painting and calibrating your leaf wetness sensor won’t work

At all times when the relative humidity of the sensor surface (RHs) is above 90%, a false positive is registered by painted leaf wetness sensors.

Plant available water: How do I determine field capacity and permanent wilting point?

To maximize crop yield, it is important to maintain soil water content somewhere between field capacity and permanent wilting point.

Why soil moisture sensors can’t tell you everything you need to know

Accurate, inexpensive soil moisture sensors make soil VWC a justifiably popular measurement, but is it the right measurement for your application?

Soil moisture sensors—how many do you need?

The number of soil moisture sensors can make the difference between proving a hypothesis or missing it entirely. How many sensors will complete a soil moisture picture?

Why we should reexamine the -1.5 MPa standard for permanent wilting point

What has been the response of the soils community to the revelation that the thousands of 15 bar measurements on soil are wrong?

Why measure Photosynthetically Active Radiation (PAR)?

Researchers can use information about different plants’ abilities to intercept and use PAR to engineer canopy structure modifications that significantly improve crop yield.

A comparison of water potential instrument ranges

Making good water potential measurements is largely a function of choosing the right instrument and using it skillfully. Read a comparison of water potential instruments and the ranges they measure.

Avoid costly engineering mistakes–Classify expansive soils using the WP4C

Geotechnical engineers need a reliable and quick method to determine how expansive a soil is. The WP4C measures soil suction and is therefore well-suited to classifying expansive soils.

When to water: Dual measurements solve the mystery

Though water potential is a better indicator of plant available water than water content, in most situations, it’s useful to combine the data from both sensors.

How to measure specific surface of soil with the WP4C

Recent research indicates that the WP4C may be a useful instrument for determining specific surface of soils.

How to assess maximum potential biomass production

The ACCUPAR LP-80 can be used to measure f, the fraction of incident radiation intercepted by the canopy, which can be used in a simple
model for understanding and analyzing parts of an ecosystem.

Soil moisture sensors—Which installation method is best?

Installing soil moisture sensors will always involve some digging. How do you accurately sample the profile while disturbing the soil as little as possible?  Consider the pros and cons of five different profile sampling strategies.

Wire splicing and sealing technique for soil moisture sensors

Employing a durable wire-splicing technique is very important when considering the harsh environments a connection must withstand.

How to model plant available water

This paper presents the information needed for simple models of soil water processes.

Predicting the amount of water on the surface of the PHYTOS 31 dielectric leaf wetness sensor

Due to the unique dielectric measurement technique used to sense wetness on the surface of the sensor, the PHYTOS 31 can also be used to quantify the amount of water on its surface, which can be a good approximation of the amount of water on the …

LAI—theory and practice

In the past, measuring LAI was difficult and time consuming. However, theory and technology developed in recent years have made measuring LAI much simpler and more feasible for a wide range of canopies.

How to create a full moisture release curve using the WP4C and HYPROP

With good measurement techniques, it is finally possible to get a complete, high-resolution soil moisture release curve.

Why beam fraction calculation in the LP-80 simplifies LAI measurements

Radiation sources must be treated separately in the computation of leaf area index from canopy transmission measurements.

Electrical conductivity of soil as a predictor of plant response

Measuring electrical conductivity can prevent saline soil, which ceases to support agricultural production.

Effects of sample disturbance on soil water potential measurements with the WP4C

Assess the magnitude of sample disturbance effects and relate them to the range of water potential of a soil sample.

Lightning surge and grounding practices

Protect your soil moisture sensors from lightning surge.

Will sample disturbance lead to lower accuracy?

For soil water potential measurement, the question of sample disturbance is important to ensure an accurate result.

Why you shouldn’t use the filter paper method to measure soil suction

In this video, Dr. Doug Cobos explains why the filter paper method can produce large errors in the suction measurement.

Is it time to recalibrate your ACCUPAR LP-80 external quantum sensor?

Recalibrate every three years for the highest accuracy.

The LP-80—Pain-free leaf area index

Leaf area index is a single number–a statistical snapshot of a canopy taken at one particular time. But that one number can lead to significant insight.

Setting SDI­-12 addresses on METER digital sensors using Campbell Scientific data loggers and LoggerNet

How to set 
SDI­-12 
addresses 
in 
METER digital sensors using 
Campbell
 Scientific
 data loggers 
and
 LoggerNet.

Simplified models for carbon assimilation by plants

The processes in photosynthesis are complicated and hard to model. But, it’s possible to simplify the model by focusing on one or more of the limitations.

Correcting temperature sensitivity of ECH2O soil moisture sensors

In many natural and engineered soils, the output of ECH2O soil moisture sensors are sensitive to variations in the soil temperature. The temperature sensitivity is not caused by the ECH2O sensors themselves, but rather the electrical …

Why measure water potential?

A comprehensive look at the science behind water potential measurement.

How to measure water potential

Learn current methods for measuring water potential and the pros and cons of each method.

Defining water potential

Understand the different components of water potential.

Water potential—a little history

Discover the history of water potential measurement.

The ACCUPAR LP-80—How accurate is it?

The LP-80 gives instant PAR measurements when you turn it on, and it also provides a measurement of Leaf Area Index–LAI. But where does this LAI measurement come from, and how accurate is it?

Soil electrical conductivity: a beginner’s guide to measurements

Irrigated land accounts for 40% of our food supply, and salts impact yields on about one-fifth of those acres.

How to generate a soil moisture characteristic using the WP4C

A soil moisture characteristic describes water storage in soil and water availability to plants, and predicts water and contaminant transport in soil.

Troubleshooting METER soil moisture sensors

In this video, application and support specialist, Chris Chambers, demonstrates his troubleshooting workflow and fixes for common problems.

Seed longevity in storage is enhanced by controlling water potential

Water activity (water potential) has distinct advantages for specifying conditions related to seed longevity.

Water potential: The key to successful seed priming

Water is known to be the most important physiological factor for seed germination. But how much water, and under which physical constraints?

Using the PHYTOS 31 Leaf Wetness Sensor as a rain detector

The PHYTOS 31 records low-level rain that does not register on a tipping bucket rain gauge.

Use of the LP-80 to quantify effects of riparian vegetation removal on stream energy balance

Riparian strips shade streams when timber is harvested or prescribed burns are undertaken. Determine how much shade and what size of strips are needed.

Easy, accurate measurement of leaf water potential using the WP4C

Leaf water potential measurements are easily and accurately obtained using the chilled-mirror dew-point technique of the WP4C.

How to measure water content of compost successfully

The basis for compost moisture reporting is not the same as for soil water content.

A quick guide to calibrating the SC-1 porometer

Learn when and how to calibrate the SC-1 Leaf Porometer.

Using SCWin (Short Cut) to read EC-5, EC-10, EC-20, MPS-1, and 10HS sensors with Campbell Scientific data loggers

How to use SCWin (Short Cut) to read ECH2O, MPS- 1, and 10HS sensors with Campbell Scientific data loggers.

How to use PAR for more efficient irrigation

Good irrigation management requires the answer to two questions: when do I turn the water on, and when do I turn it off?

Using soil water sensors for efficient irrigation in greenhouses

Irrigating with soil sensors increases plant quality, prevents stress, and reduces water use and leaching without expensive recycling irrigation systems or large ponds.

ATMOS 41—Correction of air temperature measurements from a radiation-exposed sensor

Despite its seeming simplicity, air temperature is one of the most difficult environmental parameters to measure accurately. The current best practice involves housing the air temperature sensor in a radiation shield that is either passively …

Why TDR vs. CAPACITANCE may be missing the point

When considering which soil water content sensor will work best for any application, it’s easy to overlook the obvious question: what is being measured? Time domain reflectometry (TDR) vs. capacitance is the right question for a researcher who …

Estimating relative humidity in soil—How to stop doing it wrong

Many people assume the soil is dry when it feels dry to the touch. This false assumption can lead to poor decisions such as storing steel drums of toxic waste in a desert soil. The following calculations illustrate why steel drums would corrode …

Measuring METER tensiometers with non-METER control and data acquisition systems

Find out the capabilities of METER tensiometers with respect to their ability to interface with non-METER data loggers.

Measurement volume of METER volumetric water content sensors

The results of tests conducted to quantify the measurement volume of METER’s VWC sensors.

Updating METER digital sensors

In many natural and engineered soils, the output of ECH2O soil moisture sensors are sensitive to variations in the soil temperature. The temperature sensitivity is not caused by the ECH2O sensors themselves, but rather the electrical …

Thermal properties: What you should know before measuring your soil, masonry, fluid, or other material

Using METER’s thermal properties analyzer is simple, but there are things to know before making your measurements.

All new HYPROP-VIEW software

The new HYPROP-VIEW data logging software simplifies sample-based measurements with one or several HYPROP balances.

SC-1 Leaf Porometer repair and maintenance

This video explains typical repair and maintenance for the METER SC-1 Leaf Porometer.

Video: How to install soil moisture sensors

This video explains how to install ECH2O soil moisture sensors.

SDI-12: Everything you need to know to be successful

SDI-12 is a communications protocol that comes with a myriad of possibilities for research. Understand the basics of setting up a system, SDI-12 pros and cons, and how to fix common problems.

Soil-specific calibrations for METER soil moisture sensors

Accuracy increases to ± 1-2% for all soils and soilless substrates with soil-specific calibration. Here’s a step by step guide to performing your own calibrations.