Soil monitoring at VPDrought in Pfynwald

Soil water availability is a crucial counterpart to atmospheric demand in the VPDrought project. While vapour pressure deficit (VPD) captures the dryness of the atmosphere, the ability of trees to access water depends on soil conditions. To better understand this interaction, we’ve installed a detailed soil monitoring setup across the VPDrought experiment.

Since 2023, sensors have been recording key soil parameters at eight experimental plots, each subjected to one of the following treatments: control, irrigation, irrigation + VPD, drought, and drought + VPD. Soil conditions are measured at three depths: 10, 80, and 120 cm, with three replicates per depth and treatment, capturing both shallow and deep soil dynamics. 

See raw measurements »

The following parameters are continuously monitored:

• Soil water content (m³/m³)
• Soil electrical conductivity (dS/m)
• Soil matric potential (kPa)
• Soil temperature (°C)

We use Teros 12 sensors to measure water content and conductivity, and Teros 21 sensors for matric potential and temperature (METER Group AG, Germany). Sensors are installed adjacent to the scaffolds to align with canopy-level VPD treatments.

Together, these measurements provide a high-resolution picture of belowground water dynamics, a crucial piece of the puzzle in understanding how forest ecosystems respond to increasingly frequent and hot drought conditions.