Lysimeter

A lysimeter (from Greek lysis = solution, resolution, and metron = measure ) is a device for the determination of soil water balance ( infiltration rate, evaporation) and for the sampling of soil leachate, to determine its quantity and quality. In the environment, research and agriculture lysimeters are used to detect interactions or material transport between the atmosphere, the plants, the soil, the wildlife and groundwater.

Operation

Lysimeters are open-topped cylinders, which are filled with a soil core and set into the ground so that they are flush with their environment. At the lower end of the cylinder is closed. The leachate is collected at the bottom of the cylinder and passed to a measuring device. The soil contained in the lysimeters is usually an undisturbed soil core from the vicinity, but can also be a disturbed, artificially layered soil for specific problems. The surface of the soil in the lysimeter core is mostly overgrown with vegetation of the immediate area.

Facility

When setting up a lysimeter is important to note that the installation measures a significant disturbance of the natural fabric and water balance pose ( joint between the cylinder and soil core, vegetation, and others) and that it usually takes a long time (up to one or two years ) until equilibrium is reached again and the lysimeter has adapted to its environment. Only useful measurements can be achieved.

Lysimetertypen

It is case- small lysimeters. Large-scale lysimeters are expensive physical structures of metal ( Lysimeterzylinder ) or concrete ( eg pool with natural forest vegetation). The Lysimeterzylinder have a diameter of up to 3.2 m and a height of up to 3 m. The lysimeters are partly due to scales ( weighable lysimeter) and for monitoring and sampling underground walkable ( lysimeter cellar ).

Small lysimeters have diameters of about 10-30 cm (eg metallic or ceramic) and the soil core heights are depending on the question about 10-30 cm. They can be taken together with the receptacle for the leachate from the top of the soil and weighed or sampled.

Schneelysimeter usually have a diameter of 1.60 meters and is used for determining the current Schneeabtaurate.

The Academy of Agricultural Sciences of the GDR operation north of Weimar ( Ramsla / Buttelstedt ) a lysimeter of approximately 100 m × 100 m. This could be observed in the long term water balance of cereal or potato blows. The installed at the stamping station is part of the Thuringian State Institute of Agriculture in neighboring Jena.

Measured variables

With a lysimeter measurements for water budget and mass balance of the soil and of plants ( Plants coefficient) can be obtained. The leachate quantity (infiltration) can be measured directly by trapping or determined from the weight of the lysimeter. The difference between rainfall and leachate quantity is the evaporation ( evaporation or evapotranspiration ). The chemical analysis of the leachate provides statements on the matter balance (nutrients, pollutants, and others).

Areas of application

Meteorologists use weighable lysimeters to determine the evaporation. Small lysimeters are used in environmental research to track the migration of contaminants from the soil surface into the soil ( eg, via the deposition pollutants transported ). Großlysimeteranlagen there are few in Germany. In the environment, research and agriculture provide a large-scale lysimeters soil cut again, can be studied in detail under natural conditions in the interactions and mass transport between the atmosphere, the plant, the soil, the wildlife and groundwater. Among other lysimeters are to questions that are related to global warming, are used. Furthermore lysimeters used in the chemical industry in the development of plant protection products, because data on the behavior of plant protection products must be (migration, degradation, metabolites, and others) submitted in the authorization.