soil water content and convergence issue

[rannu.bari@gmail.com]

Hi Jirka,
I am simulating several years data with different crops in HYDRUS_1D separately. I found for some crop seasons, the simulation didn't converge. Every time it stopped when it reaches at moisture content: 0.36 and 0.4476 for 2 soil layers. I can see those values are the saturated moisture content that came up in each respective soil (see the screenshot attached). That means soil gets saturated over time and stopped to converge. I noticed that if I change (increase) those values then the convergence issue is gone. Do you think I can increase the saturated moisture content? If yes, do you have any reference for the range of saturated moisture content that I can use? Or is there another way to avoid this issue?

In the first year with the first crop (very beginning of simulation), I considered initial water content ranges 0.08-1 (top one should be greater than residual water content) at the top and bottom layers and after that each crop season water content considered for the next cropping season. Am I correct about the beginning water content (0.08-1, HYDRUS-1D shows the range is 0-1)?

Thank you for your support.


Kind Regards,
Rahena

[Jirka]

When you specify the initial conditions in terms of the water content, then the values should be between the residual and saturated water content, i.e., in your case and the first material, between 0.07 and 0.36. The values cannot be larger than the saturated water content, as that is physically impossible. You should also check that the problem is physically feasible, i.e., you do not force water into an already saturated system. J.

[rannu.bari@gmail.com]

Hi Jirka,
Thank you.
If it is paddy field (soil already puddled with water for transplanting) then the initial condition for water content also should be between 0.07-0.36 or will change and i need to change it manually? I know these moisture content come up automatically with changing soil type. Does the initial condition vary for different crops and crop condition? If yes, then how will be the changing condition?


Kind Regards,
Rahena

[Jirka]

I do not have more comments on this topic. This is something you need to figure out yourself. J.

[rannu.bari@gmail.com]

Ok. Thank you.

Is there any option/file in HYDRUS-1D to check the water balance of my simulation?


Kind Regards,
Rahena

[Jirka]

This is really trivial question. I think you should study the software a little before you start posting questions and wasting my time. J.