The Crop Growth Model (CGM) is one of the seven eco-hydrological modelling tools included in the CLASS catchment-modelling framework. CGM can be used at a daily time step either as a stand-alone tool at a paddock scale or as part of the CLASS catchment model wherein CGM simulates crop growth for all grid cells under cropping in a catchment and provides growth information to the catchment hydrology model. CGM can be used to simulate most C3 crops such as wheat, barley, canola and sunflower and also C4 crops such as sorghum and maize. The model simulates green and dead dry matter, grain production, root biomass, LAI and ground cover for a range of climate, soil and management conditions. CLASS CGM provides a Windows based user-friendly graphical user interface (GUI)which guides the user through each step.

The model is designed for use by environmental science professionals including scientists, researchers, State and Federal NRM organisations, Catchment Management Authorities, consultants and students.

CLASS CGM is designed for use by professionals with varying levels of expertise in crop growth and recharge modelling. It can be used by expert scientists, modellers and agronomists to simulate crop growth. Advanced users with measured field data and a sound understanding of crop growth and soils can update parameter files and apply CGM to their own applications. In the absence of field data and parameters, default parameters inbuild in CGM database can be used.

CLASS CGM has been implemented on data from the Delegate Catchment (Snowy River basin, New South Wales) under the project ?Landscape Strategy for the Snowy Monaro Region?. CGM has also been implemented on crop growth data representative of the Riverine Region around Wagga Wagga and the results were compared with the observed crop yields.

The main features of this product are:

1. CLASS CGM provides a Windows based user-friendly graphical user interface (GUI).
2. Capability to simulate most generic C3 and C4 crops
3. Seamless integration with the Richards? equation based hydrology, an established and proven technology for accurate water balance simulations
4. Provides the ability to simulate interactions between crop growth and water balance using robust plant physiology and unsaturated zone hydrology concepts
5. The model uses adaptable sub-daily simulation time steps by sensing transient nature of the atmospheric conditions and attempts to overcome the divergence problems usually associated with solution of the Richards? equation.