Irrigation management consists of two fundamental factors; irrigation timing and amount. Pan evaporation is a classical technique used to measure evaporation rate of an open water surface and provides a strong relationship with plant water use. However, pan evaporation methods do not quantify plant water status between irrigation events it simply estimates the potential amount of plant water loss. To adequately assess water stress, measurements of water potential are required. In the past the pressure bomb provided destructive water potential measurements but at low temporal resolutions. With an automated stem psychrometer higher data resolution is attained with non-destructive methods.
1. Measure cumulative plant water status and concurrent environmental demand (i.e. VPD) under conventional irrigation management using automated stem psychrometers
2. Measure plant water status under modified (reduced) irrigation management
3. Analyze and correlate cumulative water potential and vapour pressure deficit (VPD) with the goal to predict plant water status from environmental demand (i.e. VPD)