TM
METER Large Weighing Lysimeters

METER Large Weighing Lysimeters

  • Introduction

    Modern day METER lysimeters—now in their third generation—monitor the hydraulic and thermal conditions of the surrounding field. Their sophisticated measuring, sampling, controlling, and regulating instrumentation monitors the real field situation.

  • History

    From a simple measuring tool to a highly developed monitoring system

    Soil water is the decisive parameter for mass balance determination. For studies on groundwater recharge or mass transport, or for metabolism research, it is extremely important to have a field-identical water regime inside the Lysimeter.

    For climate research or analysis of microbial activities METER Lysimeters offer thermodynamic comparability between field and lysimeter.

    Both aspects are important for many tasks, as well as considerations in research regarding:

    • conventional cultivation
    • snow coverage during winter operation
    • high substance conversion after snow melt

    Whether your field is soil science, climate research, water management, agricultural research, or remediation of contaminated sites, modern METER Lysimeters contribute essential monitoring results.

    Today high-precision sensors are available that reveal even the smallest amount of precipitation, such as dew or frost.

    High-resolution data loggers store short-interval readings over extended periods of time to visualize details of ongoing processes, mass conversion or solute transport.

    Loggers store readings internally or on USB sticks. As an option, the logger can transmit the data into a network by Ethernet or server/web server via GSM or GPRS. Thus, you can bring together data from numerous METER Lysimeter sites,
    which then are available as a common and substantial data base for a research network.

    Weighing Lysimeters
    Philippe de La Hire (1640-1718), mathematician who constructed lysimeter, well-known for his nivellements in Versailles.
    Weighing Lysimeters
    Figure 1. Coshocton-Lysimeter in 1937: Already at that time, lysimeter innovations enabled precise determination of the water balance and leachate of substances into the groundwater.
  • Basics

    Precise water and substance balances

    METER lysimeters offer precise and detailed data from the “black box” of soil. Lysimeters with high-precision weighing systems are the modern tool for studies where soil water and mass transport must be determined precisely under field-identical conditions.

    Highly accurate weighing techniques offer new applications

    Knowledge about water flow is the basis for all studies about soil water and mass balances. METER lysimeters equipped with precision weighing systems measure water flows in the soil by weighing and calculating water input and output over the time.

    METER technology has the capability to weigh lysimeter columns with a mass of up to 6000 kilograms. It measures those soil columns with an accuracy of 100 grams which corresponds to a precipitation or water column of 0.1 mm. The resolution is even10 grams or 0.01 mm precipitation. Thus, METER Lysimeters are exceptionally suitable for the measurement of all types of precipitation like rain, dew, rime and snow. And best of all, the precipitation is measured just as it actually occurs in the surrounding field—right on the soil surface.

    And, since not only the lysimeter weight, but also the leachate output is measured in the gram range, METER lysimeters can be used for calibration of groundwater recharge models.

    Finally, METER Lysimeters can confirm predictions regarding climatic change by supplying substantial data. An example of this is the TERENO-SoilCan project, for which soil columns were cut at several locations and then brought to a location with different climatic conditions for surveying.

    The mesocosmos of soil, vegetation, and micro-organisms inside the lysimeter is exposed to a natural, yet different climate. Thus, future effects due to climate change on soil, plants, water balance, CO2 and O2 dynamics can  be measured today.

    weighing lysimeters
    Figure 1. Soil water as well as input and output parameters of water and substance balance
  • Unique Cutting Technique

    Our expertise in selecting, cutting and extraction of soil columns

    To get significant data for a field, catchment area, or region, it is necessary to select a representative location. If the soil profile shows barrier layers, lenses of clay, or extreme coarse horizons, a new spot for the soil column extraction should be chosen. Otherwise, these specific characteristics must be considered in the conception as well as in the data interpretation.

    Quality assurance with the UMS cutting method

    As each soil is unique, it is essential to have experience in the cutting of lysimeter soil columns. For the past 20 years, METER has extracted hundreds of soil columns all over the world (nearby or as far as China) and in many types of soil: typical farmland, permafrost, forests, rubble plains, or alpine habitats.

    The following are some examples how the METER cutting method ensures the quality of your future measurment data:

    • We do inspection borings by hand or machine to find out if rocks, roots, cavities, or other disturbances might require preventive measures
    • We assure quality by continuous observation of the cutting process
    • We use tools to cut exactly perpendicular (a method by METER which is under protection by the utility model)
    • We use newly developed cutting edges made of a special steel which has minimized friction. This prevents soil compaction inside the lysimeter column.
    • We hand-remove stones or roots beneath the cutting edge so they cannot produce cavities or grooves on the soil column.

    Precise and gentle shear-off procedure

    The bottom of the soil column is sheared off with a polished cutting plate. The plate’s specially shaped cutting edge, together with a hydraulic drive, allows careful and accurate shearing.

    Soil conserving lifting and rotation method

    After the soil column is cut and sheared off, it is lifted and turned upside down.
    The METER method has four particular advantages:

    1. The lifting force is applied evenly and close to the balance point to prevent column deformation. The soil body is kept safe and free of deformation.
    2. The lysimeter cylinder is not deformed when lifted because the induced load torque is reduced to a minimum. The load is extensively distributed from the short bolts over the large welded-on base plate.
    3. The round bolts allow an easy, smooth, and safe rotation of the whole cylinder. This saves costs by reducing installation effort and maintenance when the lysimeter needs to be lifted.
    4. The integrity of the soil body is assured by the safe and easy handling.
    5. The filled lysimeters are transported on trucks with special air suspension to ensure that the soil column remains undisturbed. The height of the soil column is checked for quality assurance.

    The METER lifting and rotating method prevents a deformation of the soil body and eliminates the development of gaps inside the cylinder—an essential quality criterion for receiving substantial data.

    Weighing Lysimeters
    Cutting the worlds biggest single lysimeter in Chile
    Precise and gentle shear-off lysimeter procedure
    Weighing Lysimeters
    The unique METER soil conserving lifting and rotation method
  • Outstanding Lysimeter Technique

    The inventors of the field-identical water regime lysimeters

    One main point of criticism against lysimeters has always been the difference between the “water regime” in the field and inside the lysimeter.  In conventional gravity lysimeters, the leachate is just drained out of the bottom of the lysimeter. In reality, variable matric potentials, which are the driving force for water flow, occur in the field.

    In rainy seasons or wet periods, the field’s soil water is pulled toward the lower groundwater.  This does not happen inside the lysimeter, as the potential on the very bottom is zero. As a result, the lysimeter has more moisture than the field.

    In dry periods, depending on the soil type, capillary suction causes the water in the field to rise.  This is not the case in the conventional lysimeter; the soil in the lysimeter remains drier than the soil in the field.

    In METER lysimeters, this problem is solved by measuring and comparing the matric potential in both the bottom of the lyismeter and in the field at the same depth. If the lysimeter has more moisture, water is sucked out of the lysimeter through the suction cups rake. If the lysimeter is drier, water is injected. This technique has been used in all METER Lysimeters since 2004 with great success.

    High-precision weighing for reliable mass balances

    Measuring small changes of a large load under field-identical conditions—this innovative technology is what makes METER lysimeters so unique and valuable.

    For METER lysimeters this means:

    • Measurement of the soil column mass with an accuracy of 100 grams which corresponds to a precipitation or water column of 0.1 mm. The resolution is even 10 grams or 0.01 mm precipitation.
    • Leachate is measured with an accuracy of 10 grams and a resolution of 1 gram.

    The precision weighing system in METER lysimeters enables highly accurate measurement of mass increase and decrease in the lysimeter. Thus, water balance parameters of rain, dew, frost, snow and evapotranspiration are determined with the highest resolution.

    METER lysimeters are placed on three weighing cells. This minimizes measurement errors due to a shift of the load caused by wind, and it reduces statistical error. The weighing cells offer the highest accuracy, they are hermetically sealed and made of durable stainless steel. Measuring the leachate discharge is even more precise, as leachate is collected and weighed in a separate tank.

    The special design of the weighing system excludes transverse forces (patent pending). Another advantage is the fast and easy replacement and calibration of the weighing cells.

    Field-identical temperature dynamics

    All chemical and microbial processes are temperature dependent, as well as hydraulic processes. When designing a lysimeter, it is of great importance that the temperature dynamics of the field are transferred to the lysimeter as
    efficiently as possible.

    METER lysimeter well rings are made of porous concrete. Thus, the evaporation enthalpy creates a thermal equilibrium between lysimeter soil and the surrounding field (from the soil surface down to the bottom).

    The bottom side is equipped with a high thermal conductivity heat exchanger which re-establishes the thermal conduction usually interrupted in conventional lysimeters.

    Sealing the rim gap

    The gap between the lysimeter cylinder and collar is properly sealed to prevent the intrusion of rain, melting water, or stones. This reliably eliminates a former cause of error. In addition, the circulation of air caused by thermal effects is reduced. This sealed rim gap was first implemented 15 years ago, and further improvements ensure that it now in no way influences  weighing precision.

    Snow—an interfering factor?

    Snow and snow melt are important, and not only in alpine regions. With METER lysimeters you can directly measure the water equivalent of snow and the increase in snow cover by weighing. This is achieved by a special rotating blade which cuts a small gap into the snow cover straight over the lysimeter rim. With this gap, the lysimeter is weighable again, and snow fall or melting processes cause little disturbance (utility patented).

    Simple maintenance and easy replacement of sensors

    Sensors can be replaced without lifting the lysimeter through a service hatch in the collar. The weighing cells are not fixed to the bottom side of the cylinder but are hooked sideways. Thus, they can be replaced easily (patent pending).

    Careful selection of material and material processing

    METER lysimeter vessels are made of a special stainless steel and are manufactured only by skilled specialists with advanced welding experience. The narrow tolerances and the passivated welding seams must pass strict quality
    control testing. Dimensions and stability are verified and tested to guarantee long-term operation of the system.

    METER lysimeters are placed inside concrete well rings which have a thermal transmission comparable to the soil. They are designed to withstand geodynamic pressures and assure stability for years—a proven design for long-term precise weighing!

    Weighing Lysimeters
    Suction cups rake for field-identical water regimes
    Weighing Lysimeters
    High-precision weighing
    When completely surrounded by the field’s soil the lysimeter obtains a field-identical temperature profile
    Weighing Lysimeter
    Lysimeter sealing lip on a Hydro-Lysimeter
    Weighing Lysimeters
    Lysimeter service well installation for easy entry

     

Science-Lysimeter

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  • Picture
    weighing lysimeters
    Science-Lysimeter installation
    Science-Lysimeter
  • Description

    The Science Lysimeter is our modular precision measurement system for scientific studies and research in soils.

    Soil conservation is a primary aim. The knowledge about the soil’s function and usefulness as a “buffering zone” and interface to the atmosphere is fundamental and essential for future-oriented food production.

    Research work becomes a complex scientific challenge because of the variety of variables and parameters. The Science-Lysimeter is designed as a modular and configurable system for investigation of soil-specific properties, soil utility, and conservation. The Science-Lysimeter can be configured to match the task and research aim.

    These lysimeters combine the advantages of laboratory and field investigations, as they offer laboratory precision even under rough field conditions.

  • Advantages

    Advantages of the METER system solution

    1. The lysimeter can be equipped with tensiometersTDR-/FD-probes or pore water samplers in different depths to receive depth-specific information about water dynamics
    2. Identical probes are installed in the field as a reference
    3. Thus, mass balances and other results can be extrapolated from a defined lysimeter volume and surface to a wider or increased area
    4. The instrumentation can be customized and specifically selected according to your research task

    Other advantages

    • Field-identical water regime
    • Field-identical temperature regime in the lysimeter
    • Connection to Ethernet, remote control by GSM or GPRS
    • An optional device cuts snow automatically to enable weighing also during snow coverage
    • Standard lysimeter height is two meters
    • The evapotranspiration determination is done by weight measurement, not by evapotranspiration models
    • T8 Tensiometers for precise matric potential measurement
    • Silicon carbide suction cups for low sorption soil water sampling
    • Depth-graded, detailed information
    • Easy to maintain by functional lifting bolts and pluggable and addressed cabling and pluggable tubing

     

  • Scope of delivery

    Scope of delivery

    • METER lysimeter cylinder with silicon carbide porous cups rake
    • Precision weighing system
    • 2 pcs. T8 Tensiometers for regulation and supervision
    • Weighable 60 l leachate tank with controlled partial emptying to 40 l
    • 8 pcs. FD-soil moisture probes
    • 6 pcs. MPS-6 matric potential sensors
    • 8 pcs. SIC20 soil water samplers
    • 8 pcs. SF 1000 sampling bottle
    • 1 pc. VS-pro vacuum controller
    • Enclosure MBR-1 with data logger DT80, reverse flow peristaltic pump and power supply unit
    • Lysimeter concrete well shaft
    • Service well shaft (Ø 2.35 m; height 2.3 m)
    • Float switch pump with drainage system

     

  • Specifications

    Technical details

    Surface1 m²
    Soil column depth2 m
    Outer diameter1.65 m
    Total height2.35 m
    Water flux resolution0.01 mm/10 g
    Porous cups rake5100 cm²
  • Customization

    Increased monitoring capacity for comparison of various cultivation treatments

    Stations with several lysimeters increase your measuring capacity. Or compare the effects of various treatments of fertilization or irrigation under identical climatic conditions.

    Two or more METER lysimeters for comparative studies

    To determine various treatments at one site, two or more lysimeters are connected to one logger and one service well. Depending on your requests and local conditions, lysimeters can be installed in sets of two.

    They can compare diverse cultivation methods and crop rotations, as well as conventional and organic farming. For comparison studies on the same soil but with different treatments (fertilization, irrigation or CO2 treatment) up to six lysimeters can be connected to one logger and service well.

    Advantages of a tetragon layout

    The service well is installed in the corner of four fields. The length of the connection pipes is flexible, so the lysimeters can be placed far inside the field to minimize any influences from beyond the boundary ridge. If the lysimeters should be cultivated with machines, use Agro-Lysimeters with removable rings (see Agro-Lysimeter).

    Advantages of a linear layout

    To compare various crop rotations or variations from A to F in a linear alignment a parcelling of the lysimeter surrounding is recommended as this is easier to cultivate. Linearly aligned lysimeters are also recommended if autonomous robots or automatic systems for irrigation and tracer application or gas treatment hoods are used.

    Advantages of a hexagon layout

    For projects aiming at a comparison of soils under changed climatic conditions the lysimeters can be arranged as a ring. Then, the soils are brought in from different locations and are exposed and surveyed under changed climatic conditions. Because of the the geometric similarity of the hexagon layout the lysimeters are exposed to equal conditions—especially advantageous for comparative studies. Then, lysimeters A to F are filled with different mesocosmos from various locations, to represent the variability of one ecosystem.

    weighing lystimeters
    Lysimeter 90 degree layout
    Weighing lysimeters
    Lysimeter duplex field layout (Wagna)
    weighing lysimeter
    Lysimeter tetragon layout
    Weighing lysimeters
    Lysimeter hexagon circular layout (TERENO)

     

Hydro-Lysimeter

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  • Picture
    weighing lysimeters
    Hydro-lysimeter
    Diagram: Hydro-Lysimeter
  • Description

    The Hydro-Lysimeter supplies you with the most important water balance parameters with precision and reliability. Is your task to calibrate and evaluate water balance models with real data? Then you need precise data about precipitation, precipitation intensity, evapotranspiration, and leachate.

    Substantial data for professional water management, long-term monitoring, and assured projections

    The Hydro-Lysimeter offers continuously measured data. If you are a water supplier, a state or federal institution involved in water management, or a hydrographic service you receive substantial information for decision-making, monitoring or projections.

    weighing lysimeters
    “Wedding” of a Hydro-Lysimeter
    weighing lysimeters
    Frost and morning dew can be measured with the Hydro-Lysimeter
    Weighing lysimeters
    Hydro-Lysimeter with easy-to-use service well
    weighing lysimeters
    Morning scene shortly before lysimeter extraction
  • Advantages

    Advantages of the METER system solution

    1. You receive high-resolution, precise data about precipitation and evapotranspiration on the site, measured directly on the soil surface. Mass change is measured with an accuracy of 100 grams (0.1 mm precipitation) and a resolution of 10 grams (0.01 mm). Leachate is measured with an accuracy of 10 grams and a resolution of 1 gram
    2. Measure fractions of precipitation from dew and rime. Depending on the location these can accumulate to up to 100 mm in one year’s water balance
    3. Calibrate water balance models against true mesoclimatic conditions. Measure field-identical evapotranspiration, the real time evapotranspiration on the surface under true climate and water conditions.
    4. The amount and composition of leachate is gained under field-identical conditions for determination of the groundwater recharge rate in real time with high resolution
    5. Precipitation is measured directly on the soil surface considering real wind conditions, soil moisture, and vegetation. Due to the relatively large surface of one square meter you get the best possible precipitation data
    6. METER lysimeters supply information about the true water conversion processes taking place on the surface down to a selectable soil depth

    Other advantages

    • Field-identical water regime
    • Field-identical temperature regime in the lysimeter
    • Connection to Ethernet, remote control by GSM or GPRS
    • An optional tool for snow measurement automatically offers additional information about the water equivalent of snow
    • Standard lysimeter height is 1.5 meters. If required, a height of up to 2 meters is available
    • The evapotranspiration determination is done by weight measurement, not by evapotranspiration models
  • Scope of delivery
    • METER lysimeter cylinder with silicon carbide porous cups rake
    • Precision weighing system
    • 2 pcs. T8 Tensiometers for regulation and supervision
    • Weighable 60 l leachate tank with controlled partial emptying to 40 l
    • Enclosure MBR-1 with data logger DT80, reverse flow peristaltic pump and power supply unit
    • Lysimeter concrete well shaft
    • Service well shaft (Ø 2.35 m; height 2.3 m)
    • Float switch pump with drainage system
  • Specifications
    Surface1 m²
    Soil column depth
    1.5 m
    Outer diameter
    1.65 m
    Total height
    1.85 m
    Water flux resolution
    0.01 mm/10 g
    Porous cups rake
    5100 cm²

Agro-Lysimeter

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  • Picture
    Agro-Lysimeter installation
    Diagram: Agro-Lysimeter
  • Description

    Field-identical measurements for sustainable agriculture and long-term groundwater protection

    The Agro-Lysimeter visualizes the availability of water and fertilizer and measures precipitation, evapotranspiration, and leachate.

    Do you need to know where and when water and fertilizer are available for plant use? Or when fertilizers leach into the groundwater? These are just two fundamental questions required for sustainable agriculture—questions that can be answered by the Agro-Lysimeter.

    weighing lysimeters
    Agro-Lysimeter with removeable ring
    Weighing Lysimeter
    Agro-Lysimeter installation in China
    Weighing Lysimeters
    Farming above secured Agro-Lysimeter
    Weighing Lysimeters
    Agro-Lysimeter after ground preparation for seeding
  • Advantages

    Advantages of the METER system solution

    1. Water balance and matric potential, offering information about water availability and water stress, are measured within a defined volume in the depths of the main root zone
    2. Water content and matric potential are also measured beneath the main root distribution zone—to give early warning of over-fertilization and over-irrigation
    3. The amount and composition of leachate is gained under field-identical conditions and stored in the cool service well
    4. You receive highly accurate and precise data of precipitation and evapotranspiration measured directly on the soil surface. Mass change measured with an accuracy of 100 grams (0.1 mm precipitation) and a resolution of 10 grams (0.01 mm). Leachate measured with an accuracy of 10 grams and a resolution of 1 gram
    5. Option: Pore water samplers in both zones collect soil water leachate samples. Analysis of the leachate information is used to determine the availability of fertilizers and the potential threat of groundwater contamination.

    Other advantages

    • Field-identical water regime
    • Field-identical temperature regime in the lysimeter
    • Connection to Ethernet, remote control by GSM or GPRS
    • An optional device cuts snow automatically to enable weighing also during snow coverage
    • Standard lysimeter height is 1.5 meters. If required a height
      of up to 2 meters is available.
    • The evapotranspiration determination is done by weight measurement, not by evapotranspiration models
    • The upper ring section of the lysimeter cylinder can be lifted off for tillage. In addition, the load cells are hung out and the lysimeter is affixed. Then, conventional tillage operations with agricultural machinery is possible on the lysimeter soil as well.

     

  • Scope of delivery
    • UMS lysimeter cylinder with silicon carbide porous cups rake
    • Precision weighing system
    • 2 pcs. T8 Tensiometers for regulation and supervision
    • Weighable 60 l leachate tank with controlled partial emptying to 40 l
    • 2 pcs. FD/TDR soil moisture probes
    • 2 pcs. MPS-6 matrix sensors
    • Enclosure MBR-1 with data logger DT80, reverse flow peristaltic pump and power supply unit
    • Lysimeter concrete well shaft
    • Service well shaft (Ø 2.35 m; height 2.3 m)
    • Float switch pump with drainage system
  • Specifications
    Surface1 m²
    Soil column
    1.5 m
    Outer diameter
    1.65 m
    Total height
    1.85 m
    Water flux resolution
    0.01 mm/10 g
    Porous cups rake5100 cm²

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