Virtual Seminar Index

• Products:
  • AccuPAR LP-80,
  • SC-1 Leaf Porometer for Stomatal Conductance Measurements,
  • Soil Moisture Sensors,
  • EC-5 Soil Moisture Sensor,
  • Drain Gauge G3,
  • Environmental Instruments,
  • 10HS Soil Moisture Sensor,
  • Drain Gauge - Passive Capillary Lysimeter,
  • Drain Gauge G2,
  • Sensors,
  • 5TM Soil Moisture Sensor,
  • 5TE Soil Moisture Sensor,
  • Lysimeters and Infiltrometers

This index provides a list of Decagon's archived Virtual Seminars with a brief description of each seminar.  Follow the links on this page to watch any of our archived seminars.

Canopy

Basics of Leaf Porometry

Presented: February 24, 2011

Click on the title above to watch as Chris Chambers provides some useful tips and information on measuring stomatal conductance through the use of leaf porometry instrumentation. He also had the opportunity to answer several questions from attendees. The webinar touched on the following areas:

• Basics of the biology behind porometry
• Operation of Decagon’s SC-1 Leaf Porometer and why the instrument is unique
• How the SC-1 compares and differs with other porometers
• Common applications where stomatal conductance measurements are useful.

Using the Leaf Porometer in Vineyard Water Management

Presented:  May 19, 2010

Click the title to watch Dr. Mark Greenspan, one of the world's leading experts on wine grape irrigation, will discuss why he measures stomatal conductance in vineyards and how the measurement of stomatal conductance differs from the more traditional pressure chamber measurements. He will discuss basic theory of operation of the Decagon Leaf Porometer in addition to best practices for measurement in the field.

Standardized Methods for Measuring Intercepted PAR in Canopies using Ceptometers

Presented:  January 28, 2010

Click the title to watch a seminar about:  The fraction of photosynthetically active radiation that a canopy intercepts (fiPAR) drives photosynthesis. Authors rarely adequately describe how they deploy linear PAR sensors to quantify fiPAR. This virtual seminar with guest speaker Dr. Mari-Vaughn Johnson explores the need to adopt a universally accepted, repeatable sensor deployment method to produce consistent results. Dr. Johnson will show variability of fiPAR measurements by three sensor deployment methods, including two single plant methods and a transect method. She will also highlight potential implications of using the different deployment methods via an exercise in the application of the simple Lambert-Beers Law. If you are interested in canopy measurements of intercepted PAR, join us for this free virtual seminar.

Model Carbon Assimilation by Plants

Presented:  May 24, 2011

Click the title to watch the seminar:
Description: The production of total and harvestable biomass by crops depends on their ability to capture resources from their environment. Water and nutrients are obtained from the soil. CO₂ and energy (light) are obtained from the above-ground environment. Some relatively simple measurements and models can be used to quantify the efficiency with which a given cultivar can capture these resources and convert them to biomass. Dr. Campbell addresses two of these models during the virtual seminar. In the first, the factors relating light capture to biomass yield is addressed. In the second, the relationship between water capture and dry matter production is considered. Simple models are presented, along with methods for making measurements and ranges of variability among species. These models can be used for parental and cultivar selection to maximize light and water use efficiency

Basic Principles of Radiation Measurement

Presented:  July 19, 2011

Click the title to watch the seminar:
Description: Dr. Bruce Bugbee presents on the measurement of net radiation which is a critical component of the prediction of evapotranspiration and the temperature of our planet. Net radiation includes 4 components:

• Incoming shortwave radiation
• Reflected shortwave radiation
• Incoming longwave radiation
• Outgoing longwave radiation

Several new instruments have become available over the past few years to measure net radiation, but it is not always necessary to measure each radiation component separately. For many applications, a measurement of incoming shortwave radiation can be coupled with a model to predict net radiation.

This presentation discusses these methods, as well as the following:

• The sensors used for measuring photosynthetic photon flux, a measurement which can determine photosynthesis, plant growth, and yield.
• Tools and techniques to improve the accuracy of estimating plant growth and yield based on absorbed radiation.

Canopy and Soil Moisture

Quantification of Resource Capture Efficiency for Cultivar Improvement

Presented:  February 17, 2010

Click the title to watch a seminar about:  Production of total and harvestable biomass by crops depends on their ability to capture resources from their environment. Water and nutrients are obtained from the soil. CO₂ and energy (light) are obtained from the above-ground environment. Some relatively simple measurements and models can be used to quantify the efficiency with which a given cultivar can capture these resources and convert them to biomass. Dr. Campbell will address two of these models during the virtual seminar. In the first, the factors relating light capture to biomass yield will be addressed. In the second the relationship between water capture and dry matter production will be considered. Simple models will be presented, along with methods for making measurements and ranges of variability among species. These models can then be used for parental and cultivar selection to minimize light and water use efficiency.

Soil Moisture

Best Practices of Soil Moisture Field Measurements

Presented:  April 27, 2011

Click on the title above to watch Soil Moisture Product Manager Lauren Bissey present this seminar on best practices for measuring soil moisture. She covers: 

• Pre-installation sensor testing
• Site selection of soil moisture measurements
• Proper installation techniques
• What you need to document and label
• Maintenance and data collection planning

TDR in Soil - Where Can TDR Go?

Presented:  March 31, 2011

Click on the title above to watch as Dr. Topp discusses the development and success of time domain reflectometry as a means to measure volumetric water content in soils. His remarks cover: 

• The history of TDR in soil science.
• The adoption of TDR into soils research.
• Preliminary research with TDR to measure other soils parameters, such as shear strength.
• The future of TDR.

Strawberries: The Effects of Modifying Irrigation Methods for Transplant Establishment

Presented:  November 9, 2010

Click the title to watch a seminar about:  As drought management becomes an essential component of many irrigation strategies around the world, growers continue to find new ways to conserve water without compromising crop quality or yield.  This seminar investigates irrigation strategy changes by focusing on strawberry crops in California. Dr. Styles’ project addresses drought management in terms of:

• Drip irrigation vs. sprinkler irrigation
• Quantifying salinity effects on crops
• Modified irrigation timing to conserve water

Solute Signatures: Monitoring and Interpreting Salt and Nitrate Levels in the Rooz-Zone

Presented:  July 8, 2010

Click the title to watch a seminar about:  Monitoring electrical conductivity at different depths in soil can sometimes give more information about an irrigation strategy than monitoring soil moisture at the same depths in soils.  Because soluble salts (e.g. nitrate) move with the water, nitrate dynamics can provide a prompt signal of over-irrigation; something that is often missed in the interpretation of water content data.  Conversely, the accumulation of unwanted salts in the root-zone points to under-watering. In that instance salt leaves behind a signature for us to decipher. When we decode the salt signature we will find that water and solute monitoring interpret each other.  But how can a grower or scientist measure the EC levels in different soils?

In this seminar, Dr. Richard Stirzaker, a researcher at CSIRO in Australia, will address measuring electrical conductivity in different soils.  Dr. Stirzaker will compare data sets where only soil moisture is used, where both soil moisture and electrical conductivity are used.  He will also discuss how the EC measurements are made, the current limitations of the measurement techniques, and the hopes for future measurement technologies

Why Does my Soil Moisture Sensor Read Negative? How Accuracy of Dielectric Soil Moisture Sensors can Change your Data Set

Presented:  April 22, 2010

Click the title to watch a seminar about:  Dielectric soil moisture sensors are used all over the world to measure soil water content for water balances, irrigation scheduling strategies, and other plant-soil-atmosphere continuum studies. However, understanding how the instruments actually measure soil moisture will greatly enhance your ability to interpret your data. This virtual seminar will explore:

• How dielectric soil moisture sensors work
• The variables that affect the accuracy of dielectric sensors
• How to increase the accuracy of dielectric soil moisture sensors

Soil Moisture Measurement Methods and Field Applications

Presented:  March 25, 2010

Click the title to watch a seminar about:  Measuring in situ soil water content is an important part of many field research projects. Like many technology areas, instruments that measure soil water content are evolving quickly with new techniques coming into the market regularly. To make an informed decision on what technology is best for in any given situation, it is important to understand the options available on the market. The objective of this seminar is to give an overview of the different methods to measure soil water content, discuss the theory behind the measurement, and provide some examples of field research and what technology might apply in each situation. The main measurement techniques that will be discussed are gravimetric sampling, dielectric methods including TDR and FDR/capacitance, neutron probe, and dual needle heat pulse. Participants in the seminar should gain an understanding of the fundamentals behind each of the methods and in what situation each may apply.

Soil Moisture Sensors for Irrigation Control and Drought Stress Research of Greenhouse and Nursery Crops

Presented:  October 14, 2009

Click the title to watch a seminar about:   Manual irrigation is labor-intensive and repetitive, so it is one of the first greenhouse tasks that should be automated. Although automating irrigation is easy, automated systems are not necessarily water efficient. Combining soil moisture sensors with irrigation controllers can result in automated irrigation systems that can water crops based on the actual water use of the crop with minimal to no water leaching. Measurement and Control of Plant Drought Stress Levels Soil moisture sensors also have important applications in drought stress research because of the need to quantify the severity of the imposed stress. Not only can these sensors be used to measure the severity of drought stress, they also can be used to control the drought stress level. Join guest speaker Marc van Iersel from the University of Georgia for a presentation addressing two key areas in irrigation management where soil moisture sensors have been used beyond measuring the water content of soils or soilless substrates.

Using Decagon Moisture Sensors for the Precision Irrigation of Soilless Substrates

Presented:  September 11, 2009

Click the title to watch John Lea-Cox and Félix Arguedas-Rodriguez from the University of Maryland as they present results from their research. The goal of their research is to precisely measure real-time volumetric water content and soil matric potential in a range of soilless substrates, which are commonly used in the nursery and greenhouse industry.

The research team at the University of Maryland has set up Decagon sensor networks in soil nursery production systems, as well as a pot-in-pot (large container) production nursery. They will share tips for establishing networks in the field, and examine some real-time data from those systems, including environmental data. If you are interested in using Decagon soil moisture sensors in soilless substrate, or simply interested in alternative applications for soil moisture sensors, we welcome your participation in this virtual seminar.

Soil Drainage

Methods of Sampling and Analyzing Soil Pore Solution

Presented:  June 28, 2011

Click on the title above to watch as Leo Rivera and Chris Chambers present on various methods and tools available for  extracting soil pore water solution, continuous or discontinuous extraction, tensiometer controlled suction, proper sample storage, and proper pore water sampler material selection depending on chemical suitability. The presentation also covers different methods of analyzing the solute, their advantages and disadvantages, and what to look for.

Measurements and Models for Macropore Infiltration in Soil

Presented:  January 25, 2011

Click on the title above to watch as Dr. John Norman shows how to use a single-ring, dual-head, ponded infiltration technique with the analysis of Reynolds and Elrick to get key parameters for use in a macropore infiltration model. These same measurements can also be used to obtain values of the saturated hydraulic conductivity which is useful for traditional infiltration models such as the Green and Ampt formulation. Macropore models that include characterization of the geometry of the macropores tend to be complicated and require more parameters than can be determined from a reasonable set of independent measurements. The M&M model is a relatively simple macropore model that requires only nine parameters. Three or four of these can be determined from a standard description of soil structure. One comes from the Coefficient of Linear Extensibility and four or five are obtained from ponded-infiltration and hydraulic properties measurements. This seminar will focus on the ponded infiltration measurements. The parameters from hydraulic properties will be the subject of another seminar.

Lysimetry Basics

Presented:  October 19, 2010

Click the title to watch a seminar about:  All studies of soil water and mass balances need to begin with an understanding of water flow. A question you might need to answer when conducting your research is “how does water move through the soil and what does it take with it?” Quantification of water and solute (e.g. nutrients, pesticides, pathogens) fluxes through the soil traditionally have been difficult to accurately measure, until recently.

This virtual seminar will discuss several techniques for measuring soil water drainage including: water balance residual, zero tension pan lysimeters, static tension wick lysimeters, small scale controlled tension lysimeters and large scale lysimetry. We will focus on the merits, drawbacks, and relative cost of each drainage measurement technique.

New Vadose Zone Monitoring Technology

Presented:  July 27, 2010

Click on the title above to view the slides from the seminar about how minimization of subsurface pollution and optimization of remediation efficiency depend on reliable and effective subsurface-monitoring tools that provide real-time information on the chemical and hydrological state of the percolating water. Unfortunately, today, most monitoring programs are based on information obtained from observation wells penetrating groundwater. As such, identification of pollution in well water is clear evidence that the groundwater has already been contaminated, and only little can be done to fully remediate the contaminated aquifers. Accordingly, effective monitoring program that aims at protecting groundwater from potential pollution must include vadose-zone monitoring technology that provides real-time information on the hydrological and chemical properties of the percolating water, long before contaminants reach the water table. Hence, monitoring and analyzing the vadose-zone provides "early warning" for potential contamination that may risk groundwater.

Soil Water Drainage Measurement and Soil Water Sampling

Presented:  November 19, 2009

Click the title to watch a seminar about:  Accurate quantification of solute (e.g. nutrient, pesticide, pathogen) fluxes through the soil has traditionally been difficult, requiring the accurate measurement of both the soil water flux (drainage) and the concentration of the solute in the soil water. This virtual seminar will discuss several techniques for measuring soil water drainage including water balance residual, zero tension pan lysimeters, static tension wick lysimeters, small scale controlled tension lysimeters, and large scale lysimetry. We will focus on the merits, drawbacks, and relative cost of each drainage measurement technique. The presentation will also cover methods of collecting soil water for solute concentration analysis including porous suction cups and plates. Consideration will be given to the sorption effects due to the chemical composition of the porous cup/plate, and limitations in effective sampling range due to the air entry potential of the porous material.

Soil Water Potential

Accurate and Reliable Soil Moisture Characteristic curves (Moisture Release Curves) Using Vapor Pressure Methods

Presented:  December 10, 2010

Click on the title to watch Dr. Doug Cobos demonstrated how to make a soil moisture characteristic curve (SMCC). Soil moisture characteristic curves plot the relationship between water content and water potential for soil (or any porous medium).  Knowing a soil’s unique characteristic allows you to:

• estimate water potential from a measured water content

• estimate the amount of plant available water in soil

• evaluate the expansiveness of a soil. 

Quick Methods for Determining Plant Available Water

Presented:  October 28, 2010

Click the title to watch Dr. Gaylon Campbell's seminar about: For the first few days after a heavy rain or irrigation the water drains from the soil profile untilits water content approaches a relatively stable value called the drained upper limit or field capacity.  When plants have extracted all of the water available to them, the root zone water content approaches a lower limit of available water, or permanent wilting water content.  The water held by the soil between these two limits is called plant available water.  These two limits are often associated with water content values at specific soil water potentials.  Field capacity is often taken as the water content of a soil at -33 kPa water potential.  Permanent wilt is taken as the water content at -1500 kPa.  Methods typically used for determining plant available water are slow and inaccurate.  Join us as we present a method to measure field capacity using a tensiometer and an extrapolation technique, and a method to measure permanent wilting water content with a dew point potentiameter and an extrapolation method which are both much faster and more accurate then traditional methods.

Water Potential: Which Method Should I Use?

Presented:  November 30, 2011

Making good water potential measurements is largely a function of choosing the right instrument and using it skillfully. It is a difficult measurement to make, and no single method for measuring water potential is able to cover the entire working range. Join Dr. Gaylon Campbell in a free virtual seminar as he guides users through:

• Advantages and disadvantages of instruments measuring water potential.
• The range and accuracy of various sensors and instruments.
• Practical advice on choosing the best sensor for a particular application.

Software

Introducing DataTrac 3

Presented:  April 6, 2011

Click the title above to watch how new DataTrac 3 transforms endless columns and rows of soil moisture and environmental data into meaningful metrics, such as plant available water, vapor pressure deficit, and growing degree days. In this virtual seminar, we’ll walk you through the basics of the new software and take your questions on putting DataTrac 3 to work for you.  During the seminar, you’ll learn how to:

1. Automatically collect data from Decagon data loggers
2. Create growing tools, such as plant available water and vapor pressure deficit
3. Create irrigation reports with annotated graphs, target zones, and recommendations

Thermal Properties

Tips for Accurately Measuring Termal Conductivity and Resistivity of Porous Materials

Presented:  February 1, 2011

Click on the title above to watch as Dr. Todd Vanek presents tips on how to accurately measure thermal conductivity and resistivity in porous materials like soil, back-fill material, and concrete.  Specifically, Todd discussed: 

• Proper measurement techniques for using a thermal needle probe
• The role of thermal dryout curves for understanding thermal resistivity of soils
• The advantages and disadvantages of the three methods used to obtain thermal dryout curves (modeling, single sample, multiple sample)
• Ideas on a new method to obtain a thermal dryout curve