## Search found 14 matches

Fri Jul 05, 2019 2:18 pm
Forum: Hydrus 1D
Topic: Nitrogen simulation
Replies: 1
Views: 558

### Nitrogen simulation

We know Hydrus is not a crop-based model, however, it has interesting possibilities for solute transport modelling for my work. So to simulate 150kg N/ha applied in the sowing day is it true to assume all that in the first 5 top cm of the soil profile as the initial condition. Assuming the depth of ...
Sat Mar 23, 2019 2:40 pm
Forum: RETC
Topic: Why Thetas>1
Replies: 1
Views: 1122

### Why Thetas>1

Hello,
Could you please let me know where am I wrong? I got Ts>1 and big alpha value
Thanks
but the fitting with these numbers work well

60 0.507
100 0.44
300 0.408
500 0.324
1000 0.313
2000 0.286
15000 0.269
Sun Oct 07, 2018 5:02 pm
Forum: Hydrus 1D
Topic: Matlab run problem
Replies: 5
Views: 1503

### Re: Matlab run problem

Thanks for reply, could you please post the contact of relevant person about matlab and hydrus in PC progress.
Ali
Fri Oct 05, 2018 7:32 am
Forum: Hydrus 1D
Topic: Matlab run problem
Replies: 5
Views: 1503

### Matlab run problem

Hi
I just rewrite the example of hydrus run by matlab (https://www.pc-progress.com/Downloads/T ... Hydrus.pdf),
but there is something wrong that the run is not done and Matlab stays busy for ever.
Please find the attached file and see if you can find where I made mistake.
Thanks
Wed Aug 01, 2018 12:07 pm
Forum: Hydrus 1D
Topic: Inverse modeling convergence problem
Replies: 1
Views: 797

### Inverse modeling convergence problem

Hi,
In the attached file why the problem is not converged by normal VG but converged by Modified VG, how possible to converge by VG. In general, How we can understand inverse modeling with VG model is impossible and DPMs are alternatives and if so how to initially guess the extra parameters of DPMs?
Thu Jul 26, 2018 8:49 am
Forum: Hydrus 1D
Topic: Inverse modeling of drip infiltrometer
Replies: 1
Views: 814

### Inverse modeling of drip infiltrometer

Hi,
The data from Infiltrometer experiment are used in Hydrus to obtain inversely the VG paramter and Ks but the simulation is not converged see the attached file please. I would be please if any one could help me out.
Tue Mar 27, 2018 9:10 am
Forum: Hydrus 1D
Topic: Inconvergence in Inverse Modeling
Replies: 1
Views: 936

### Inconvergence in Inverse Modeling

Hi, In the below problem the inverse solution is not converged! why? 20cm Column, top boundary condition variable flux (Kodtop -3), bottom boundary -30cm pressure head. and 6 Observation node for h and k(h). Data for model is attached. I also considered the right properties of pressure plate (like o...
Mon Mar 26, 2018 9:56 am
Forum: Hydrus 1D
Topic: ThetaS larger than 1
Replies: 1
Views: 861

### ThetaS larger than 1

How to tackle with some unreasonable solutions from inverse modeling such as Thetas>1? The coulum is under variable flux condition o to (a pump with different rates) and variable pressure head at bottom(starting form -100cm to -30cm ) within 21 hrs.
Wed Mar 07, 2018 4:16 pm
Forum: HP1 (HYDRUS-1D - PHREEQC)
Topic: Basic statement for transpiration rate
Replies: 1
Views: 1908

### Basic statement for transpiration rate

Hi,
What is the BASIC statement for Transpiration rate needed for Kinetic rate of passive uptake? I used { rate = water_sink(cell_no)*tot("Species") ---> moles = -rate*time} but there was Bad Script error because of "water_sink". What is the proper statement?
Wed Jan 03, 2018 9:28 am
Forum: HP1 (HYDRUS-1D - PHREEQC)
Topic: Solute Time Variable Boundary Condition
Replies: 1
Views: 1997

### Solute Time Variable Boundary Condition

Hi, I am wondering how its possible to apply time variable boundary condition which includes X mol/kgw of an insoluble mineral in water. For more clarification lets consider I have a mineral based fertilizer which is roughly insoluble (Log_k=-50) and at sowing day of planting it is applied. Firs I n...
Thu Nov 30, 2017 10:08 am
Forum: Hydrus 1D
Topic: Nitrogen fertilizer HYDRUS1D
Replies: 3
Views: 2178

### Re: Nitrogen fertilizer HYDRUS1D

Dr. Jirka, In the Portugal Example, Kd is assumed to be 3.5cm3/g while mmol was chosen as Mass Unit shall it be altered by 0.063cm3/mmol! I was wrong sorry its related to g of soil as kd=C/S. I dont delete it maybe later its another person's question. Then I am modeling Urea and NPK fertilization (n...
Sat Nov 25, 2017 6:57 pm
Forum: Hydrus 1D
Topic: Nitrogen fertilizer HYDRUS1D
Replies: 3
Views: 2178

### Nitrogen fertilizer HYDRUS1D

Dear Readers, Lets assume 100kg(N)/ha of NPK (10-10-20) results in 7.1 mmol/cm2 to convert it to concentration or mmol/cm3 (cTop) I need to run a water flow simulation and get the water content at first 5cm, i.e. fertilization dressing height on field (theta*Z with dimension of L or cm) at time of f...
Tue Oct 24, 2017 3:41 pm
Forum: Hydrus 1D
Topic: Numerical Solution in NoT converged
Replies: 3
Views: 2101

### Re: Numerical Solution in NoT converged

For course-textured soils, you usually need to use lower values of hCritA and the wilting point to achieve convergence (due to the steep retention curve for the pressure heads below about – 5 m). See the discussion in the help. J. Dear Dr. Simunek, Thanks a lot for very helpful hint. I used h(theta...
Mon Oct 23, 2017 6:56 pm
Forum: Hydrus 1D
Topic: Numerical Solution in NoT converged
Replies: 3
Views: 2101

### Numerical Solution in NoT converged

Hello, I am simulating water flow by 40year PET, LAI and other required data for different soils. As I got helpful point from forum I established correct input data such as rsoil and etc (top BC:atmospheric, BotBC: Free drainage), (Delta min,init and max ) but the simulation for the coarse texture l...