Actual harvest date different from the simulated harvest date

AquaCrop-OSPy (Python)
#1

Hello

I set the actual crop harvest date together with the sowing date in the crop parameter. Also the simulation start and end date are made the same as the sowing and harvest date. However, when I run the simulation, in the output cell I get a different harvest date two weeks earlier than the actual harvest date. The good news is I get the same yield output from AquaCrop as in the actual field output, only decimals less. But, I have an assumption if AquaCrop didn’t conclude the simulation two weeks earlier and if it allowed the crop to stay in the field for those extra days, there might be a yield gain, I guess. The opposite could also happen, due to further drying and moisture loss. Anyway, is there a possibility to force AquaCrop-OSPy run the simulation until the actual harvest date and avoid the difference. Please refer the attached file.

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#2

Hi Ade,

Two things to note here -

  1. In Aquacrop, the simulation end date is not the same as the harvest date. The simulation end date indicates the latest possible harvest date, meaning, the simulated harvest date can not go beyond this but can be before the stipulated simulation end date.

  2. Yes, it is possible to match (nearly match) the simulated harvest date with the actual harvest date by adjusting some of the crop parameters. I see that you have used a built-in crop (wheat) and have used the default crop parameters ( you have commented out the crop parameters so I am assuming you have used the default crop parameters). I would suggest you start adjusting the non-conservative crop parameters and check if the simulated harvest date is pushed a little further; start with 1-2 non-conservative parameters (cultivar specific params). If adjusting the non-conservative parameters does not seem to help, only then, start tweaking the conservative parameters by a small margin. So, for instance, in this case, because I notice early harvest, I would want to slow down the canopy growth rate and or the canopy decline rate so as to slightly push the maturity/harvest date a little further. Therefore, I decide to reduce the value of CGC and/or CDC by a small margin from the reported default value and then run the simulation and check if there is any change in the simulated harvest date. I will continue this exercise until the simulated harvest date matches (nearly matches) the actual harvest date. I am just giving an example of changing CGC/CDC here. These parameters are conservative parameters. I would suggest you start by adjusting the non-conservative parameters and if that does not help, you can move to adjusting the conservative parameters.

Hope this helps. Let us know if you have any further questions.

-Amoolya

#3

An additional point to note is that All of the current default crops (except potato) are in growing degree mode. If you instead specify the crop calendar in calendars days, you will be able to harvest on the exact same day each year. The latest pull request includes every AquaCrop default crop and will make this process a lot easier