Fruit growth is the most important and most critical parameter for growers when deciding whether to irrigate or not. The planned project is based on the development of an easy to use and practical optical sensor system allowing to monitor fruit growth in the orchard automatically. The sensors will be integrated into a wireless system connecting a range of other already existing sensors (such as soil moisture sensors and flow meters) and actors (such as valves). Using fruit growth, the system determines automatically the minimum point when to irrigate again. Soil moisture sensors for instance allow then to determine when to switch irrigation off again. The system will be build up as an autonomous system with the possibility of the user adjusting values at all times

Growers will thus be enabled to run the irrigation on the lowest possible level while maintaining and securing fruit growth. Since the system automatically records every measurement and the amounts of water applied, full documentation will be created to confer with EU-guidelines such as the water framework directive on using and securing water resources.

A combination of laboratory and field experiments will be used to develop and test a sensor for fruit growth measurements based on an optical system. Additionally, field experiments will be used to determine thresholds and tolerances in fruit growth in relation to the available soil water.