APSIM

APSIM stands for Agricultural Production Systems sIMulator. It is a modular, open-source software framework designed to simulate agricultural production systems. By linking climate data, soil properties, crop growth models, and management actions, APSIM can compute outputs such as grain yield, soil water use, nutrient dynamics, and environmental impacts.

The software uses a component-based architecture, with modules for crops (for example wheat, maize, sorghum), soils, weather inputs, and management decisions (planting dates, fertilizer application, irrigation). Users assemble simulations by connecting modules and providing input data. APSIM supports scenario testing, model calibration and validation, and sensitivity analysis.

APSIM originated in Australia during the 1990s through collaboration among CSIRO, universities, and agricultural research groups. It has since been developed and maintained by the APSIM Initiative with contributions from an international community of researchers. It is used by researchers, extension services, and industry globally.

Applications include evaluating management strategies, optimizing water and nitrogen use, assessing environmental outcomes such as leaching and emissions, and exploring climate-change scenarios. The framework supports various crops and soils and can model rotations, soil organic matter dynamics, and irrigation schedules.

APSIM is distributed as open-source software with graphical and script-based interfaces. The project maintains a modern version known as APSIM Next Generation (APSIM-X), which emphasizes modularity, performance, and interoperability with other tools and data standards. The user community and documentation provide tutorials and examples to support reproducible research.