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This will bring up a dialog. The dialog has several parts.
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Green (far left)
A list of water users that a crop table can be attached to. Clicking on a water user will bring up the crop table for that water user.
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At the bottom is an “Autogenerate” button. This will run a simulation of the crops with zero rainfall and the evaporation from the time series specified. Optionally it can save the time series from the simulation to a file as csv - once clicked the user will be asked to specify whether to save, and if so, where. See the Autgenerate section for details.
Blue (3rd from top)
This is the data on the crop mix. It should not be entered directly. Instead as the crop data is entered this will be updated.
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Go to the Planting Decision.
We want to set the area.
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- Click on the planting decision for that crop
- Create a modelled variable
- Click on “+”
- Select Modelled Variable
- Node > Water User > (name of your water user) > Demand Model > Crops > (name of your primary crop) > Area
- It is recommended you give the variable a meaningful name like wateruser3_rice_area
- Create a function
- Click on “+”
- Select Function
- Multiply the modelled variable by the relative proportion compared to the primary crop. (Divide by the primary proportion to get crop mix area, multiply by the proportion of the current crop)
- A simple example might be $wateruser3_rice_area*(60/40)
- It is recommended you give the function a meaningful name
- Select function
- Right click on the function created and select “Select and Lock Usage”
Autogeneration of parameters
It is possible to Autogenerate the seasonal information from the Crop Table Plugin Dialog.
This runs a simulation of the crop over the evaporation period, with an assumed rainfall of zero, and perfect watering for a single 'unit' area. It then stores this required usage.
To do this you must have
- Correct crops, including planting dates (the table provides a summary of what has been entered in Source).
- Correct seasonal dates (Chosen by the user)
- An evaporation time series that is from a Data Source (this will be auto-detected and present in the dialog)
Once these are correct, click on "Autogenerate".
You will be asked to choose a fallow soil depletion. This is required because over a long period with evaporation but no rainfall the 'Fallow' area of the irrigator will become completely depleted of water. At planting time the crop will be assumed to have the fallow soil depletion. This option overrides this normal behaviour.
You will then be given the option to save the results of the crop simulation to file.
After this you will either get an error, or notification the autogeneration was successful.
Autogeneration Output File
Columns are Date, then (for each crop, starting with Fallow) Season, Area, Factor, Stress, Evap, Water Supplied, Soil Depletion, Fallow Soil Depletion, Returned, Usage.
Rows are daily for the period of evaporation.
NOTE: this will be a large file.
Troubleshooting
If your primary crop dies before your secondary crops are planted, then the planting function will be incorrect. It is possible to set a function to look “backwards” at what the area was on a given date.
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