NB2

[maobw12]

Hello, I have made localisation changes to the HI of crops and a series of cycles in NB2, but I have some problems: when I modify only HI and the crop cycle is set to the parameters of the GAEZ official website (mean180 min90 max250), the simulated crop yields are normal; however, when I set the cycle, I selected cycle255, mincycle165, maxcycle277, the simulated yields are all 0. In response to this phenomenon, I checked the NB2 code, and found that the cycle of rainfed and irrigated is related to the LGP, LGPt5, so I also checked my LGP, which is in line with the logic of the code, but a lot of my yields come out to be 0, and so I am very puzzled about this situation. This is very puzzling and I don't know which step is wrong. Here is the sample image, looking forward to your reply! Figure 1 is NB2 determining the cycle code section; Figure 2 is the cycle parameters I set; Figure 3 is my LGP with LGPt5; Figure 4 is the result of my NB2 simulation, irr and rain are almost 0

[maobw12]

When I modify the minimum cycle to 90, more than half of the raster elements are still 0

[NokuzaSezo97]

Hi @maobw12,

The code screenshot you provided is the conditional logic whether a particular pixel location meets minimum cycle length requirements with the number of growing days. Depending on rainfed or irrigated conditions, the minimum cycle length is compared with LGP (R) or LGPt5 or LGP1to (I) depending on minimum temperature requirement. If the LGP/LGPt is less than your crop's minimum cycle length requirements, that means the location is not suitable for crop growth as the minimum cycle length demand does not meet.

In this particular example, I can't say for certain that the code screenshot causes a large area of zero yield because the northern part have LGP/LGPt greater than your revised minimum cycle length. Because having zero yield can be from different conditional sources, I would suggest to do a checklist of the following to have a comprehensive understanding:

1. Permafrost conditon
2. Thermal Screening criteria condition (fc1)
3. Moisture Deficit (fc2)

You also mentioned that the harvest index has changed but the value is not mentioned. Note that AEZ methodology considers the maximum HI value to obtain maximum yield. If HI becomes closer to zero, obviously you encounter lesser amount of yield, no matter how much gross biomass the crop sustains.

Regards,

Swun Wunna Htet

[maobw12]

Here's the deal. I set up four sets of parameters, modifying HI with cycle (mean min max). In the first group, I set the harvest index to 0.53 and the crop cycle to 180 90 250; in the second group, 0.5 180 90 250; in the third group, 0.53 255 165 277; and in the fourth group, 0.5 255 165 277. The results are as follows: the first two groups without modifying the crop cycle have normal crop yields, and the last two groups have zero, for which I have modified the I have modified the mincycle to 80 20, etc., but the results did not improve. I would like to ask that the crop cycle is only related to LGP LGPt5, right, so the problem is with the crop cycle. So for your question about permafrost conditions, thermal screening standard conditions (fc1), and moisture deficit (fc2) is it no longer relevant?

[maobw12]

Can I ask if the crop cycle can only be selected according to the schedule?Can I ask if the crop cycle can only be selected according to the schedule? For example, winter wheat has the following cycles, can they only be selected here?