Example settings for the Hoogendoorn iSii process computer pertaining to the Grodan 6 phase reference table.
Start time / Stop time
The Grodan water content meter is connected to a level tray module.
- Start based on radiation, time or Grodan water content meter in the period: from sunrise until 2 hours before sunset:
- The irrigation strategy is set with an interval time and a delay time. The interval time is the minimum time between two cycles and the interval time + delay time is the maximum time between two cycles. Eg set the interval time at 15 minutes and the delay time at 45 minutes. In a very sunny day you will get a cycle every 15 minutes (= IT). At a very dark day every hour (=IT+DT).
- Start on radiation if the actual radiation is higher than 150 W/m² and the radiation sum is higher than 100 J/cm²
WC level during the day
Water content decrease to 60% during the day.
WC decrease at night | Time of 1st drain
Regulate the decrease in the water content for the night to 8-10% on a sunny day, and to 10-12% on a darker day. Regulate at the time of first drain in 4 cycles to reach 400 J/cm² or 600 W/m².
In this example a chart is included because there is no setting for a rate reduction with a water content meter.
In case of using a Hoogendoorn AquaBalance (to control the saturation weight of the slab) it is possible to set a rate reduction.
The EC supply is 2.8 mS/cm on a darker day, and 2.5 mS/cm on a sunny day.
Drain % over 24 hours
Regulate the drain % over 24 hours to 15-25% on a sunny day and to 10-15% on a darker day.
Frequency can be increased at such a low drain% through an influence of drain% on radiation sum start. So the lower the drain%, the lower the radiation sum (and vice versa).
The cycle size is 400 cc/m² (=ml/m²) on a darker day. On a sunny day, the first 3-4 cycles are 400 cc/m², then 300 cc/m².