no3_out was underestimated at its peaks

[Tetsuro Kikuchi]

Hello,

I'm running SWAT+ (rev. 61.0.1) with Editor (3.0.2) to simulate nitrate nitrogen outflow (no3_out) from a small watershed.

As shown in the attached figure, the simulated no3_out ("Sim (Lsim)"; unit: kg/day) basically underestimated the value estimated from the observation ("Est (Lest)") at its peaks. For example, the simulation could not reproduce the largest peak in the beginning of November 2022 at all.

Manual calibration of the relevant parameters was performed using RSWAT, which, however, could not substantially improved the model performance.

In the simulation, crop management schedule, including the timing and dose of fertilizer application, was set according to the actual condition as far as possible.

I'd greatly appreciate it if you could provide possible causes of this issue and solutions for them.

The corresponding TxtInOut file is also attached.

Tetsuro Kikuchi