Implementation of PESTICIDES

[Etienne Delaloye]

Hello to all of you,

I am currently working on a challenging project aiming at creating a methodology to simulate pesticides in a watershed, from Golf courses. I've used QSWAT+2.4.7 in QGIS 3.28.7, and SWAT+Editor v. 2.0

1) I have already quite satistyingly simulated discharge at the outlet (Qsim vs Qobs) over the period 2013-2020 (2 burnin years 2011-2012);

2) The idea now would be to implement pesticide application rates in the form of decision tables in SWAT+Editor.

Indeed I would like to test whether it's possible to simulate the relative contribution of pesticides that would be departing from a given LANDUSE (landuse = 'rgne' given as SWAT_CODE), down at the outlet? across time (so with concentrations varying according to discharge)?

Inputs:

- I have 6 pesticides with known quantities over a typical year (kg/ha)

- I had already (see screenshot) filled up the 'constituents' in SWAT+Editor - Edit Inputs but it's not precise and the results are not good; but i don't know if that's necessary, should i delete it if I create decision tables?

- I'd like to implement a decision table exactly similarly to that of the screenshot but with my own data, HOW can I proceed so that SWAT+Editor understands I want that those pesticides are applied over a certain landuse? ('RNGE')?.

In the screenshot 'landuse', my 'RNGE' was associated with 'meadow_intensive', corresponding to the grey polygon.

THANKS a lot if you can help me!!

Etienne

[Natalja C.]

Hello,

To answer your question: " HOW can I proceed so that SWAT+Editor understands I want that those pesticides are applied over a certain landuse? ('RNGE')?." --> you are thinking the other way around.

You do not need to tell the DT to apply it on RNGE, but you have to tell the RNGE to use this DT. :)

It is done via the management setup --> choose your RNGE landuse --> auto operations.  From there, choose your DT for pesticide application.

Hope this helps,

Natalja