🌾 SwaNET · Quick Tutorial 12 of 19

Crop Management

Set up planting schedules, irrigation, fertilization, tillage, grazing, and crop rotations — 16 management operations configurable by date or heat units.

SwaNET Tutorial 12Prereq: Loaded SwaNET Project8 min read

Key Concepts

File type.mgt — Management files
16 operationsPlanting, irrigation, fertilizer, tillage, grazing, and more
SchedulingBy calendar date or accumulated heat units
RotationsMulti-year crop rotations with year add/delete

○Overview

M4W SwaNET allows users to incorporate various crop management activities and crop rotations. A total of 16 types of management operations can be simulated, all configured through .mgt files.

Access the Interface

  1. Click Edit SWAT Databases, then Management (.mgt).
  2. Select a subbasin, landuse, soil, and slope to identify the target HRU. Click Continue.
  3. Click the Operations tab at the top. The existing crop management operations for the selected HRU are displayed.

1Core Workflow

Add an Operation

  1. Select the row after which the new operation should appear — click its Op. ID button.
  2. Click Add operation. A dialog lists all available operation types. Select one and click OK.
  3. If scheduling by date, enter the month and day. If by heat units, enter the heat-unit threshold. The operation number (OP_NUM) auto-populates.
  4. Click Save. The operation appears in the table.

Edit or Delete Operations

Edit: Select the row via its Op. ID button, click Edit operation, modify parameters, and click OK.

Delete an operation: Select the row, then click Delete operation.

Delete an entire year: Select any row within the target year, click Delete year, and confirm. All operations for that year are removed and remaining years are renumbered.

Add a rotation year: Click Add year. A new year with a default "Plant begin growing season" operation is appended.

2Operation Scheduling

SwaNET supports two scheduling modes:

  1. Schedule by date — Select this option. All operations reset to January 1st; update individual dates via the Edit function afterward.
  2. Schedule by heat units — Select this option. All operations reset to heat unit 0; update individual thresholds afterward.
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Switching modes resets all triggers. When you toggle between date and heat-unit scheduling, all existing start points are cleared. Re-edit each operation's timing after switching.

3Save & Load Schedules

  1. Save: Click Save schedule to download the current schedule as HSAmgtOp.sch (a JSON file).
  2. Load: Click Load schedule, browse to a previously saved file, and open it.
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Format note: SwaNET schedule files are JSON-based and are not compatible with schedules created by ArcSWAT or QSWAT.

4Apply the Changes

Choose what to extend and where to apply:

  1. Check Extend ALL MGT general parameters to copy all management settings, or Extend management operations to copy only the operations table.
  2. Current HRU only — "Extend edits to current HRU."
  3. All HRUs — "Extend edits to ALL HRUs."
  4. Selected HRUs — "Extend edits to selected HRUs," then pick subbasins, landuses, soils, and slopes.
  5. Click Save Edits and close the interface.
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Don't forget: Click Save Edits again on the main Edit SWAT Data interface.

5All 16 Crop Management Operations

Each card shows the operation description and tunable parameters. For full details, refer to the SWAT input/output documentation (.MGT).

Planting / Begin Growing Season

Initializes a specific land cover or plant type in the HRU.

PLANT_ID Plant type selection
Heat units Total heat units to maturity 0 – 6000
CURYR_MAT Current age of trees (years)
LAI_INIT Initial leaf area index 0 – 8
BIO_INIT Initial biomass (kg/ha) 0 – 200
HI_TARG Harvest index target 0 – 1
BIO_TARG Biomass target (t/ha) 0 – 200
CNOP SCS CN II 0 – 95

Irrigation

Applies a specified depth of irrigation water on a given day.

IRR_AMT Depth applied (mm) 0 – 100
IRR_SALT Salt concentration (mg/kg)
IRR_EFM Efficiency 0 – 1
IRR_SQ Surface runoff ratio 0 – 1
IRR_SC Irrigation code
IRR_NO Source location ID

Fertilizer Application

Applies fertilizer on a specific day.

FERT_ID Fertilizer type
FRT_KG Amount (kg/ha) 0 – 500
FRT_SURFACE Fraction to top 10mm 0 – 1

Pesticide Application

Applies pesticide on a specific day.

PEST_ID Pesticide type
PST_KG Amount (kg/ha) 0 – 200
PST_DEP Incorporation depth (mm) 0 – 1
View remaining 12 operations

Harvest and Kill

Harvests yield and incorporates remaining biomass as residue.

CNOP SCS CN II 0 – 95

Tillage

Mixes upper soil layer and redistributes nutrients and chemicals.

TILL_ID Tillage type
CNOP SCS CN II 0 – 95

Harvest Only

Harvests part of biomass; remaining biomass continues growing.

HARVEFF Harvest efficiency 0 – 1
HI_OVR Harvest index override
IHV_GBM Grain(1) or biomass(0) harvest

Grazing

Removes biomass and simultaneously deposits manure.

MANURE_ID Manure type
GRZ_DAYS Grazing days 0 – 366
BIO_EAT Biomass consumed/day (kg/ha) 0 – 500
BIO_TRMP Biomass trampled/day (kg/ha) 0 – 500
MANURE_KG Manure deposited/day (kg/ha) 0 – 500

Auto Irrigation Initialization

Triggers irrigation automatically when plants experience water stress.

WSTRS_ID Water stress identifier
AUTO_WSTRS Stress threshold 0 – 1
IRR_EFF Efficiency 0 – 1
IRR_MX Max application (mm) 0 – 100
IRR_ASQ Surface runoff ratio 0 – 1
IRR_SCA Source code
IRR_NOA Source location ID

Auto Fertilization

Triggers fertilizer when nitrogen stress reaches a threshold.

AFERT_ID Fertilizer type
AUTO_NSTRS N stress trigger 0 – 3000
AUTO_NAPP Max N per application (kg/ha) 0 – 100
AUTO_NYR Max N per year (kg/ha) 0 – 100
AUTO_EFF Application efficiency 0 – 2
AFRT_SURFACE Fraction to top 10mm 0 – 1

Street Sweeping

Removes sediment and nutrient build-up on impervious areas.

SWEEPEFF Removal efficiency 0 – 1
FR_CURB Fraction of curb available 0 – 1

Release / Impound

Releases or impounds water in HRUs.

IMP_TRIG Release/impound action flag

Continuous Fertilization

Applies fertilizer/manure on a continuous, recurring basis.

CERT_ID Fertilizer type
FERT_DAYS Duration (days) 0 – 365
IFRT_FREQ Frequency (days) 0 – 60
CFRT_KG Amount per application (kg/ha) 0 – 200

Continuous Pesticide

Applies pesticides on a continuous, recurring basis.

CPST_ID Pesticide type
PEST_DAYS Duration (days) 0 – 365
IPEST_FREQ Frequency (days) 0 – 60
CPST_KG Amount per day (kg/ha) 0 – 200

Burn Operation

Burns a specified fraction of biomass and residue.

BURN_FRLB Fraction burned 0 – 1

Skip to Beginning of Year

Marks the end of operations for the current rotation year. No parameters.