Lysimeters – a perfect tool for :

- Climate change research (including trace gases)- Water balance- Migration processes- Isotopic transport- Ecosystem modeling- Leaching

The actual evapotranspiration can easily be derived using the following equation:

Eta = P - D ± S (1)

ETa actual evapotranspiration (mm)P precipitation (mm)D amount of seepage water (mm)S change in the amount of water stored (mm, based on measuring the weight change of the soil column over time; 1 kg ≈ 1 l/m² = 1 mm)

If the water balance is calculated correctly, the solute balance can be determined with sufficient accuracy using the following equation:

L = Cs D (2)

L solute load of (mg/m²)Cs solute concentration in the seepage water (mg/L)D amount of seepage water (l/m² = mm).

Lysimeter constructions

Surface area: 0,1 m² … 0,5 m²1,0 m² … 5,0 m²

Length: 1,0 m … 3,0 m

Material: stainless steel

PE-HD; PP; PVC Lysimeter bottom: sectional,

sloped (diagonal) Sensor installation: pressure resistant

inlets

Weight of a monolith: 3.000 … 12.500 kg

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Max. Evapotranspiration 0.59 mm/h

Max. Dew Formation 0.04 mm/h

Average Evapotranspiration 0.17 mm/hAverage Evapotranspiration 0.17 mm/h

No Precipitation 5.5 mm Precipitation (= 5.5 kg)

Date

Example of the diurnal change of the weight of a gravitation lysimeter planted with grass.

LysimeterLysimeters are an important tool for water-balancestudies in agriculture, forestry and other environmentalsettings. In particular, they make it possible toquantify actual evaporation from a bare soil or actualevapotranspiration from a soil covered by vegetation.Moreover, seepage from lysimeters can be collected,which allows an assessment of the water loss from asoil profile and thus groundwater recharge. The seepagewater can be analyzed in the laboratory for itsvarious constituents. Hence, lysimeters can be used tomonitor the fate of solutes in a soil.Weighable lysimeters can monitor the mass continuouslyand thus provide detailed information aboutwater-storage changes in the soil for any time period.In conjunction with rainfall and seepage measurements,water losses can then be specified as seepageor evapotranspiration.So lysimeters simulate the natural relation betweensoil, atmosphere and plants and represent the link betweenstudies in the laboratory and in the field scale.

Our flexible lysimeter design, the facilities andadditional electronic measuring devices allow theinvestigation of various environmental questions.

Functional principle:Gravitation lysimeters are used to measure parametersfor the calculation of water and solute balances in soils. Due to the high resolution weighing system theinput water fractions are measured with a resolution of 0,01 mm, including dew, rime, the water equivalent of snowfall and small rates of evapotranspiration. In connection with the additional recording of theamounts of percolating water and precipitation it also permits the quantification of the water balance of thesoil column. The actual evapotranspiration can easily be derived using following equation:

LYSIMETER EXCAVATION TECHNOLOGYFOR MINERALIC SOILS(Patent-No.: 10 048 089.6; 10 2005 062 896;EP 07 712 322.2)

A tripod frame, which can be dismantled for transport, is used to bring the lysimeter vessel into a vertical position and hold it exactly vertical during the cutting process. The vessel is made of stainless steel and can be coated on the inside with an inert protective surface. At the top of the frame, there is a hydraulic cylinder, which in conjunction with guard and adjustable slip rails guides the lysimeter vessel during the cutting process. At the bottom of the vessel, there is a rotary cutting tool. It is driven by a small hydraulic motor, also located at the bottom of the vessel using a chain and sprocket arrangement. The cutting tool can be fitted with various types of chisels to adjust it to soil and site conditions.Advantages of new excavation technologies• Prevention of rim effects between the soil monolith and the lysimeter vessel using special soil adapted instruments (chisel and shearing lamellas)• No disturbance of the monolithically soil structure, like compression (no deformation) or changes of the microstructure of the soil through the applicationof the excavator shovel• Axial guidance of the leveled lysimeter vessel down to the extraction depth, prevention of soil fractions• Operation with extreme light and movable excavation tools, for the use in rough terrain, rise of the productivity and cost savings• Detection of hindrance, e.g. stones, inclusions or other under the use of online observation (with recording) and manual interaction in the chink• Easy movable excavation tool, e.g. eases to react on detection of hindrance, which will detract the quality of the monolith (stones, inclusions etc.)• Well visible soil profile, as the excavation pit is not damaged• Possibility of soil mapping after lifting the monolith out of the pit (it is visible which soil horizons or soil layers are in the vessel)• Minimal damage of the surrounding area by using the excavation tools and no need to dig out the area around the vessel

Drylab

Mobile roofingFor field experiments with controlled water entry, which is particularly important for irrigation experiments in the area of climate research, UGT GmbH has developed roof constructions adjusted to the relevant task. The commonality of the roof constructions is in their mobility. In order to keep the influence of the roofing on all other factors as low as possible, the roof segments are put up over the stock automatically, just for the duration of a precipitation event. This technology was used for lysimeter systems for the first time in 2009 in DryLab in Eberswalde. The effect of drought stress on types of trees from various origins was investigated on tree plantations, using eight weighable, high tech lysimeters. The plants in the lysimeters are irrigated and automatically covered with 2.5 m roof segments over a total length of 13 m in the case of precipitation events. The data collected here helps to adjust forest stocks to climate changes. For drought stress experiments on a large scale, UGT GmbH developed a roof construction for forest stocks with adult trees. These are "under roofed". The framework construction made of aluminium is individually adjusted to the trial area.Only 10 to max. 20% are permanently roofed; the remaining area is automatically covered with tarpaulins in the case of precipitation, which are rolled up in when it is dry. Therefore disturbance to the micro climate is kept to a minimum.

China, ShixiaIn 2010 UGT GmbH set up a 2-fold lysimeter station in China located in the Miyun catchment area, around 60 km North East of Peking, in the course of a joint German-Chinese project. The project is funded by the Federal Ministry of Education and Research and should help to minimise diffuse substance input, particularly NO3-, from areas used for agriculture.The weighable lysimeters with a surface of 1m² and a length of 1.7m were installed in a trial site used for agriculture in the middle of the Miyun catchment area. Fitted with suction probe systems, soil moisture meters and tensiometers at various soil depths, these two lysimeters provide the necessary information about the water and matter balance of this agricultural area, and therefore provides the basis for new management strategies. In order to guarantee absolutely natural field conditions, the monoliths were taken in a corn field with plants that were already fully grown. In order to resist the new climatic conditions, a new construction was developed for the lysimeter collar in the scope of this project.

View at the newly installed lysimeter station at the Miyun reservoir

France, HomécourtIn France UGT GmbH supports the soil remediation measures at the former steel and coal industry location Homécourt.In order to collect data for the development of remediation strategies, a large lysimeter station was set up, with 24 weighable lysimeters with an area of 1 m² and a length of 2 m. In order to observe the movement of hazardous substances in the soil, ground water samples are taken from various depths for laboratory analysis, using suction probe technology from UGT GmbH. Additionally, experiments are being carried out on the effect of the vegetation on the reduction of hazardous substances in the soil, in 24 variously planted plate lysimeters.

View over the lysimeter station Homécourt

Switzerland, Zurich-ReckenholzUGT GmbH set up Europe's largest lysimeter station on the campus of Agroscope Reckenholz-Tänikon in Zurich. A total of 72 lysimeters are installed in the large capacity station. The soil monoliths used for this were acquired from 3 different cantons in Switzerland and have a cross section of 1 m² and a length of 1.5 m.12 of the lysimeters are weighable and have high tech equipment such as tensiometers, temperature sensors, suction probes and TDR probes each at four depths. The focus of the remaining lysimeters is seepage water identification according to quantity and quality. Apart from its size which to this day is unique in Europe, this station particularly stands out due to the innovative installation and the high resolution weighing technology of the lysimeters. For maintenance works, the lysimeters can be lowered from their normal measurement position to a maintenance position. In this way all sensors are freely accessible, even those that are concealed between the soil surface and the cellar ceiling during measurements. For such a large project the control and logger technology had to be adjusted accordingly. The 14 data loggers are connected to each other via a network. This enables flexible, highly effective data compilation and storing, as well as the automatic transfer of the data to the PCs of authorised users and/or a database. The station was completed in February 2008 and has been in operation for agronomical research experiments since then.

View over the lysimeter station

Germany, UNESCO – biosphere reserve SpreewaldThe Innovationsnetzwerk Klimaanpassung Brandenburg Berlin (INKA BB) [Innovation network for climate adjustment Brandenburg Berlin] wants to secure the sustainability of land and water usage in the region, even under changed climate conditions.Amongst other things, it will be investigated in the Oberspreewald region how the various strategies for water level control in lowland areas affect the water retention in the lowland area, the water abstraction in lowland areas or the evaporation of lowland areas. Due to a more flexible water management, better adjusted to changing conditions, the consequences of extreme weather conditions, such as heavy precipitation or drought periods are to be reduced.UGT GmbH installed a lysimeter plant in the Stauabsenkung Nord (reservoir lowering area) of the Oberspreewald region for this experiment.

Extraction of four soil monoliths in the restrained area