The Agricultural Production Systems simulator (APSIM) is internationally recognized as a highly advanced simulator of agricultural systems. It contains a suite of modules which enable the simulation of systems that cover a range of plant, animal, soil, climate and management interactions. APSIM is undergoing continual development, with new capability added to regular releases of official versions. Its development and maintenance is underpinned by rigorous science and software engineering standards. The APSIM Initiative has been established to promote the development and use of the science modules and infrastructure software of APSIM.

APSIM 7.10 Application examples at

https://github.com/APSIMInitiative/APSIM710/tree/master/Examples

Documentation

https://github.com/APSIMInitiative/APSIM710/tree/master/Documentation

Common Tasks in APSIM

https://github.com/APSIMInitiative/APSIM710/tree/master/Documentation/TrainingManualsandResources/CommonTasksinAPSIM

Mind that APSIM is a complex model, but a very well elaborated one in Agricultural applications.

It must be possible to apply it on a raster based level, otherwise the diagnostics will be inferior to other raster based models.

Check it out. There is a lot of info on this model and its applications!

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Running the APSIM (Agricultural Production Systems sIMulator) crop model at a grid scale involves several steps, including setting up the model, preparing input data, running simulations, and analyzing the results. Here’s a comprehensive and detailed guide to help you through the process:

Step 1: Understanding APSIM

APSIM is a highly advanced simulation tool used for modeling and researching agricultural systems. It can simulate the growth of crops, pasture, and trees, and the changes in soil properties. Running APSIM at a grid scale means performing simulations over a spatial grid, which can provide insights into spatial variability and large-scale agricultural trends.

Step 2: Installation and Setup

• Download and Install APSIM: Ensure you have the latest version of APSIM installed on your computer. You can download it from the APSIM website.
• System Requirements: Ensure your computer meets the system requirements for running APSIM, including sufficient RAM and processing power, as grid-scale simulations can be computationally intensive.
• APSIM Next Generation: Consider using APSIM Next Generation, which has improved features and supports better handling of grid-based simulations.

Step 3: Preparing Input Data

Running APSIM at a grid scale requires spatially explicit input data. This includes climate data, soil data, and management practices.

Step 4: Setting Up the Grid

• Define Grid Resolution: Choose an appropriate grid resolution (e.g., 1 km x 1 km). The resolution should balance the detail of spatial variability with computational feasibility.
• Grid Coordinates: Create a grid with coordinates that cover your study area. Each grid cell will represent a separate simulation.

Step 5: Configuring APSIM for Grid-Based Simulations

Step 6: Running Simulations

• Parallel Processing: To handle the computational load, run simulations in parallel. Tools like High-Performance Computing (HPC) clusters or cloud-based services (e.g., AWS, Google Cloud) can significantly speed up the process.
• APSIM Batch Mode: Use APSIM’s batch mode capabilities to execute multiple simulations simultaneously. Refer to APSIM’s documentation for specific command-line instructions.

Step 7: Post-Processing and Analysis

Step 8: Validation and Calibration

• Validation: Compare the simulation results with observed data to validate the model’s accuracy. Use statistical metrics like RMSE (Root Mean Square Error) and R² (Coefficient of Determination) for validation.
• Calibration: Adjust model parameters as necessary to improve the fit between simulated and observed data. This iterative process ensures the model reliably represents the real-world system.

Step 9: Documentation and Reporting

• Document the Process: Keep detailed records of all steps, including data sources, assumptions, parameter values, and scripts used.
• Reporting: Prepare comprehensive reports and visualizations to communicate your findings. Include maps, graphs, and tables that illustrate the spatial variability and key insights from your simulations.

Additional Resources

• APSIM Support: Utilize APSIM’s extensive documentation and support forums for guidance and troubleshooting.
• Community Collaboration: Engage with the APSIM user community to share experiences and solutions to common challenges.

By following these steps, you can effectively run the APSIM crop model at a grid scale and leverage its capabilities to gain valuable insights into agricultural systems.