Question About Biomass Outputs for Multiple Crops in a Single HRU SWAT+

[Ilef Abid]

1. Primary Issue Location

Component: SWAT+ Executable / Model Functionality

Area of Impact: Model output – Plant growth and biomass reporting in plant communities

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2. Software Versions

GIS Interface: QSWAT+ (QSWAT+ 3.2.2)

SWAT+ Editor: (3.2.3)

SWAT+ Revision: (please specify revision number)

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3. Project Characteristics

Watershed Details:

• Small watershed located in Tunisia.
• One main HRU at the watershed outlet.
• Agroforestry system represented using a plant community.
• Community consists of olive trees (olive) and oats (oats) growing simultaneously within the same HRU.

Modeling Aim:

• Crop growth simulation.
• Biomass production assessment.
• Evaluation of agroforestry representation in SWAT+.

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4. Description of IssueThe Problem

I am simulating an agroforestry system using a plant community composed of olive trees and oats growing simultaneously in the same HRU.

The simulation runs successfully, but I am unable to identify which output file reports the biomass of each individual plant species within the plant community.

I would like to know:

• Which output file contains biomass values for each species separately (olive and oats)?
• Whether SWAT+ reports plant biomass individually when multiple species coexist in a single HRU.
• If not, how biomass is aggregated and reported in the outputs.

Steps to Reproduce

1. Create a plant community containing olive and oats.
2. Assign the community to an HRU.
3. Run the SWAT+ simulation.
4. Inspect the output files (plant_gro, hru_pw, hru-ls, etc.).
5. Unable to determine where the biomass of each species is stored separately.

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