Closed JJguri closed 3 years ago
Each of those stick functions has a x_ABC and y_ABC parameter. The x_ABC parameters are the x coordinates of the stick function, y_ABC similarly for y coords Sometimes ABC relates supply:demand ratio to some stress process (eg leaf expansion here). You may not see N stress if there's no water flow to transport N?
Thanks @peter-devoil . Could you please let me know where they are defined? Particularly swdef_expan
and n_stress_expan
. I can see in one the stress is close to 1 and in the other close to 0, so I want to understand the ratio and the numerator and denominator of the ratios.
It's implemented here. Parameters read here. Wheat parameters here.
If you want to explore it; do a 100 year (dryland) run with daily outputs of water supply (esw) & demand (Eo). Plot their ratio against swdef_expan, and verify it's the same slope as the parameters describe.
You'll find N calcs in the same file; but remember that N uptake only happens when water is being sucked out - ie by mass flow. If there's no water flow the calculation is irrelevant.
thanks @peter-devoil, is there a variable/parameter which specified if there is enough mass flow or not for N uptake?. Otherwise, I need to classify seasons when the crop was under (or not) water stress and assume that when it was, the N uptake was not happening. I will explore the calculations of the N factors, so it they are 0 probably it is because there was not flow that day.
@peter-devoil do you think the calculation of the NNI could be useful to assess the level of N stress during the growing season? I output this daily and as an average of the growing season. It was calculated as follows (Cte is only for comparison purposes):
if (biomass_wt > 0) then
Na = biomass_n/biomass_wt*100
NNI = Na/n_conc_crit
Cte = 1
endif
I'd leave that Q to somebody more qualified. There has been much discussion on the merits of using a target n concentration vs SLN. If I understand correctly, n_conc targets vary through the plant's lifecycle, where SLN doesn't. @uqghamme and @hut104 may have more detail, and certainly more reading material.
This issue has been automatically marked as stale because it has not had any activity in the last 30 days. It will be closed in one week if no further activity occurs. Thank you for your contributions.
This issue is being closed because there has been no recent activity. Feel free to re-open or open a new issue if needed.
Could some one explain which is the difference between x_stress_expand and xdef_expand? I am using swdef_expand to test water stress on wheat simulations. However when I want to use the same parameter for N it does not exist. Therefore, I am using n_stress_expand. Although, they have the same value range 0-1, I can deduce that stress is higher close to 1 in n_stress_expand, which is the contrary for swdef_expand. While I can see values of n_stress_expand during a wet year, it is 0 during dry years. Is it because there was not a N stress on the crop under the dry year?