In May 2007, a partnership project commenced between the Royal Botanic Gardens, Melbourne, the University of Melbourne and Sentek Sensor Technologies Pty Ltd to study the water consumption of plants in highly diverse urban landscapes. To date, research in this area has been minimal. The project is still currently running- however, there have already been several findings from this study.
Central to the study, Sentek supplied the RBG with multi-sensor capacitance type soil moisture monitoring probes (EnviroSCAN®) to monitor four garden beds. These probes have 5 sensors at varying depths to monitor soil moisture and plant root uptake. Much was learnt about the moisture extraction patterns of deep rooted plants such as trees. The moisture conditions can be monitored in real time via the Internet and therefore the scheduling of irrigation is more closely matched to the needs of the plants.
Scheduling of irrigation in garden beds, comprising mixed plantings, requires knowledge of not only the water requirements of the plantings, but also the soil water behaviour. The root systems of different species are spread over varying depths and soil properties can change down the profile. Additionally ground treatments such as mulch, significantly influence the way in which water, rainfall and irrigation enter the soil.
A major breakthrough in this trial was the development of a novel stress indicator called the Evapotranspiration Stress Index (ETSI) based on measurements of volumetric soil moisture and ETo data. Evapotransiration rates are quantified by analysing data from an automatic weather station, soil moisture sensing technology and assessments of plant performance.
Further outcomes of this research are expected to further improve the irrigation scheduling methods in urban landscapes and public open spaces. We will keep you updated over the next 12 months with information on how the project is progressing.
The full report will be available for download here shortly.
