Dear sir,
I'm studying the water uptake amount of a deep root crop at different depths.I want to know how to determine the actual amount of water uptake by roots within a certain depth range with hydrus1d. I tried to sum and integrate sink terms of different depths, and I found that their results were the same. All of them (12.9cm) were significantly lower than the total root water absorption (56cm).I used the trapz() function in the caTools package of R software for integration (Trapezoid Rule Numerical Integration).
I need your help.
I look forward to your reply.
Thank your!
Minguo Liu
How to calculate the root water uptake of a certain soil depth range
Re: How to calculate the root water uptake of a certain soil depth range
The root water uptake from different depths, Sink [1/T] (e.g., 1/day), is reported in the Nod_inf.out file. If you integrate this value over a root zone (multiply by lengths associated with each node of the root zone), you will get the actual transpiration rate [L/T] (e.g., cm/d; T_a=integral(Sink*dx)). This value should be equal to the value vRoot [L/T] reported in T_Level.out. If it is not, you do it wrong. If you integrate this only over a certain soil layer, you get root water uptake from this layer.
If you integrate T_a over time, you get cumulative actual transpiration rate [L] (e.g., cm). J.
If you integrate T_a over time, you get cumulative actual transpiration rate [L] (e.g., cm). J.
Re: How to calculate the root water uptake of a certain soil depth range
Dear Jirka,
Thank you for your reply!
I used the the Sink , is reported in the Nod_inf.out file, to calculate Ta with T_a=integral(Sink*dx) at different time points, and the result was consistent with vRoot item (corresponding time point) in T_Level.out file. However, i still have a problem. Although the root water uptake is similar at the corresponding time point bewteen vRoot and Ta, why the vRoot drawing fromT_Level.out file and sink drawing with integral have completely different results.I submit the two figures as attachments.Can`t I directly integrate Ta over Time to calculate the cumulative root water uptake?
Thank you!
Minguo Liu
Thank you for your reply!
I used the the Sink , is reported in the Nod_inf.out file, to calculate Ta with T_a=integral(Sink*dx) at different time points, and the result was consistent with vRoot item (corresponding time point) in T_Level.out file. However, i still have a problem. Although the root water uptake is similar at the corresponding time point bewteen vRoot and Ta, why the vRoot drawing fromT_Level.out file and sink drawing with integral have completely different results.I submit the two figures as attachments.Can`t I directly integrate Ta over Time to calculate the cumulative root water uptake?
Thank you!
Minguo Liu
 Attachments

 vRoot.png (7.47 KiB) Viewed 627 times

 Ta.png (7.92 KiB) Viewed 627 times
Re: How to calculate the root water uptake of a certain soil depth range
You will need to figure this out yourself. It is all pretty simple. I know that it is simpler to ask for help than to try to resolve it yourself, but you should at least try. J.
Re: How to calculate the root water uptake of a certain soil depth range
Thank you for your help and advice. I have tried hundreds of times this week, and I enjoy it. I will continue to try. I think it may be that I don't understand how each index of the model is calculated. Tomorrow is China's traditional festival. With very best wishes for your happiness in the New Year.