Third-Generation Lysimeters: Scientific Engineered Monitoring Systems

Third-generation lysimeters meet the needs of 21st century environmental research and monitoring. High-resolution sensors, field-replicating hydraulic and thermal conditions and an excavation method showing the soil inside the lysimeter cylinder are important features in their quality process chain. Older lysimeter systems are unable to provide such detailed information about the soil water budget and all linked processes. Due to an increasing awareness of climate change, water management, agronomy and soil science issues, it was essential to upgrade lysimeter systems in order to gather more detailed information about processes and fluxes. Different lysimeter station layouts were developed for specific requirements and to increase their fields of application for particular tasks such as fertilisation treatments or irrigation and reproducing identical climatic conditions. Additionally, highly engineered third-generation bespoke lysimeter types are available to support particular projects. As an example, the meteorological lysimeter precisely measures precipitation, evapotranspiration and leachate. For this, the lysimeter weighs to the nearest gramme range a surface of 1 m² and supplies results to an accuracy of 0.01 mm for water input such as rain, dew, frost or snow and water output by evapotranspiration and leachate as well as reporting the change of soil water content. Combined with additionally measured meteorological data, this enables water balance models to be developed and potential evapotranspiration can be determined.