University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Doctoral Thesis:
Reinhard Nolz
(2013):
Performance assessment of selected devices for monitoring soil water balance components with respects to agricultural water management.
Doctoral Thesis - Institut für Hydraulik und landeskulturelle Wasserwirtschaft (IHLW),
BOKU-Universität für Bodenkultur,
pp 99.
UB BOKU
obvsg
FullText
- Abstract:
- Knowledge about the water cycle and its components is crucial for various environmental topics, in particular agricultural water management. Lysimeters and soil water status sensors are valuable instruments for water balance studies. Measurement systems should be state-of-the-art regarding configuration and data management. The main objectives of this thesis are the performance assessment of a weighing lysimeter facility and selected soil water sensors integrated into a remote monitoring network. The weighing lysimeter facility in Groß-Enzersdorf, Austria operates with a lever-arm-counterbalance-weighing system. Experiments have shown that the weighing system itself is subject to mechanical oscillations and that disturbances such as wind gusts significantly decrease measuring accuracy. An approach to improve accuracy was verified by modifying the averaging process that is applied on raw data before logging. Alternatively, smoothing functions were tested and evaluated on data severely affected by wind. Two types of matric potential sensors (Watermark and MPS-1), and two multi-sensor capacitance probes for measuring soil water content (EnviroSCAN and Aquacheck) were evaluated. A general calibration function was determined for the Watermark sensors using pressure plate apparatus. For the MPS-1, sensor-specific calibrations became essential due to very high inter-sensor-variability. The MPS-1 were also calibrated in a pressure plate apparatus, and four different calibration functions were set up and evaluated. During a drying experiment in a thin soil layer, reaction time and measuring range of both sensor types were verified. A pairwise comparison of AquaCheck and EnviroSCAN readings in the respective depth showed considerable variations between single sensors of the AquaCheck probe despite factory normalization.
- Betreuer: Loiskandl Willibald
- 1. Berater: Cepuder Peter
- 2. Berater: Kammerer Gerhard