SWAT+ Nutrient Balance: Nitrification and Denitrification Remain Zero

[safa ben ali]

  Hello everyone,

I have successfully built and run my SWAT+ model, and I am now working on the nutrient balance.

However, I noticed that in the nutrient balance results, both nitrification and denitrification remain equal to 0.00, while the other nitrogen processes are simulated (plant uptake, organic N losses, etc.).

I would like to understand:

1. What are the most common reasons why nitrification and denitrification remain zero in SWAT+?
2. Which parameters should I check or calibrate to activate or increase these processes?
3. How can I calibrate the nitrogen cycle (especially nitrate dynamics) without affecting the calibrated hydrological balance?
4. Are there any recommended parameters or workflows for nutrient calibration after the hydrology has already been calibrated?

Any advice, documentation, or examples from your experience would be greatly appreciated.

Thank you very much