As part of an innovation project funded by the Federal Office for Agriculture and Food (BLE), the Geisenheim Institute of Vegetable Crops, the German Weather Service (DWD) and the Helm-Software, the Geisenheim Irrigation Scheduling for field vegetables is getting closer to practice via GS-Mobil.
The principles of the Geisenheim Irrigation Scheduling are based on the balance between evaporation, precipitation and irrigation quantities. The evapotranspiration is calculated on the basis of reference evapotranspiration and kc values. These kc values depend on the plant species and development. Since the changes in kc value are described by the temperature sum based model, the users no longer need to record the plant development in order to select the appropriate kc value (Fig. 1).
The results from the project showed that the dynamic adaptation of kc values can be achieved with the temperature sum model, which facilitates the application of the Geisenheim Irrigation Scheduling. The Helm-Software and DWD were able to create the basis of user friendly GPS- and server-supported irrigation consulting system GS-Mobil, which is available for lettuce and onion.
The modelling of kc values based on temperature sums. The course of the curve derived from the parameters resulted from the relationship between fresh mass and temperature sum (Fig. 4 and 5).