Irrigation Scheduling

In this example the date when the soil water content will reach the lower limit is being calculated.

The lower limit is set to REFILL-10mm, and the amount is the volume required to bring soil moisture back to the full point.

Scheduling screen

Irrigations can be scheduled by calculating either...

  1. The date when the soil moisture will reach a given lower limit (usually the refill point) [Mode=Lower]
  2. The amount that will be needed at a given date, to bring the soil moisture back to the full point. [Mode=Date]
  3. The amount that will be needed to balance the daily water use of the crop (Mode=Drip)

Three separate irrigations are predicted, based on three different values of daily water use...

  1. Probe DWU - what is actually happening (9.9 in the example)
  2. Estimate DWU - what the user thinks will happen (3.6)
  3. Historical DWU - what has happened in the past, or from a model (6.0, and in fact coming from a file called GRAPES.DWU)

The amounts can be displayed in...

The LOWER limit can be either constant, or it can vary during the season...

Limit Formula Result
Refill constant at refill throughout the season
Refill+20 20 mm above refill
Refill+(Full-Refill)*0.2 20% * deficit
and for flexible RDI control... 
Refill+(Full-Refill)*GRAPES.RDI where GRAPES.RDI is a curve with the required deficit at different stages in the growing season.
The RDI curves can be created and edited with edit season file

The irrigation schedule can be printed as a diagram, or as numbers.