In Europe, about 2,500 lysimeters are installed. They were originally built for investigations of the hydrological cycle, pesticide degradation, and nutrient fluxes (e.g., Winton and Weber, 1996). Present research areas of lysimeter studies include biological processes, such as root development of plants and enzyme activities (e.g., Dizer et al., 2002; Schloter et al., 2005), which are often closely related to soil structure.
At present, data on soil structure can be estimated by transferring the information of the surrounding soil to the lysimeter at the beginning of an experiment. After long-term experimentation, there was a lack of knowledge on the transformations and evolution of the lysimeter soil. Former methods (e.g., Keese and Knappe, 1996; Godlinski et al., 2004), which removed the soil manually from the lysimeter vessel or which forced the soil out of the casing by applying large pressure, were dissatisfying because the soil structure was largely disturbed.
A new technique, the Lysimeter Soil Retriever tool (LSR) (Reth et al., 2006), was developed to retrieve the soil out of lysimeter vessels with minimal disturbance of soil structure. This technique also makes the sampling of lysimeter soil more time-efficient and reproducible. The method can be applied to a range of lysimeter sizes from 0.5 to 2m2 and up to 2m deep.
The soil-filled lysimeter vessel is placed vertically in the LSR on a platform with a roll-riding system and fixed with a collar (Fig. 1).
The monolith is cut free at the rim in order to avoid compressing of the soil, when axial pressure is applied to overcome the fraction force between monolith and the vessel wall (see Fig. 2 A). For this purpose, a wire-saw is threaded through a borehole drilled along the edge of the monolith from top to the base. Both ends of the saw are connected with a wire-lock and stretched over a rolling guide. Under high cutting speed (>28 m s–1), generated by a hydraulic drive, a vertical cut is performed while the lysimeter vessel rotated 360°.
After cutting, the soil monolith rests freely on a telescopic hydraulic ram so that it can be lifted stepwise out of the lysimeter casing. The top portion is cut-off horizontally with a second wire saw, which is fixed in a ring holding system (Fig. 2 B). A plate following immediately behind the saw holds the undisturbed soil slice. The complete monolith segment is supported by a plate and ring which is then lowered down for detailed analysis (Fig. 3).
The new LSR technique allows first time lysimeter soils to be analysed with minimal disturbance after a long-term experiment. Depending on the requirements of the experiment, the thickness of the slices can be varied from a few centimetres up to 1 m. The retrieving of intact soil slices allows a much broader range of applications of lysimeters as changes in the soil system can be analysed almost in situ.
Dizer, H., Fischer, B., Sepulveda, I., Loffredo, E., Senesi, N., Santana, F., Hansen, P.-D. (2002): Estrogenic effect of leachates and soil extracts from lysimeters spiked with sewage sludge. Environ. Toxicol. 17, 105–112.
Godlinski, F., Leinweber, P., Meissner, R., Seeger, J. (2004): Phosphorus status of soil and leaching losses: results from operating and dismantled lysimeters after 15 experimental years. Nutr. Cyc. Agroecosys. 68, 47–57.
Keese, U., Knappe, S. (1996): Problemstellung und allgemeine Angaben zu vergleichenden Untersuchungen zwischen Lysimetern und ihren Herkunftsflächen am Beispiel von 3 typischen Böden Mitteldeutschlands unter landwirtschaftlicher Nutzung. Arch. Acker Pflanzen. Boden 6, 409–429.
Reth, S., Seyfarth, M., Gefke, O., Friedrich, H. (2006): Deutsche Patentanmeldung, Patentnr. 102006010158.8–52. Vorrichtung und Verfahren zur Entnahme eines Bodenmonolithen aus einem Lysimetergefäß.
Schloter, M., Winkler, J. B., Aneja, M., Koch, N., Fleischmann, F., Pritsch, K., Heller, W., Stich, S., Grams, T. E. E., Göttlein, A., Matyssek, R., Munch, J. C. (2005): Short term effects of ozone on the plant-rhizosphere-bulk soil system of young beech trees. Plant Biol. 7, 728–736.
Winton, K., Weber, J. B. (1996): A review of field lysimeter studies to describe the environmental fate of pesticides. Weed Technol. 10, 202–209.