APSIM

APSIM stands for Agricultural Production Systems sIMulator.

The APSIM modelling framework has many advantages. One of the main benefits, and also one of the most important design specifications, is the ability to integrate models derived in fragmented research efforts. This enables research from one discipline or domain to be transported to the benefit of some other discipline or domain. It also facilitates comparison of models or sub-models on a common platform.

This functionality has been achieved via the implementation of a "plug-in-pull-out" approach to APSIM design. APSIM has been developed in a way that allows the user to configure a model by choosing a set of sub-models from a suite of crop, soil and utility modules. Any logical combination of modules can be simply specified by the user "plugging-in" required modules and "pulling out" any modules no longer required.

As with any system, there are logical boundaries in that a system being simulated will require the necessary elements (in this case, modules) of that system to be valid, but the possible valid permutations of sub-models are many and varied. For example, APSIM could easily allow the user to simulate a cropping system using 2 different water balances, 2 different soil Nitrogen balances and 3 separate wheat models. The user would be able to try all 12 permutations of cropping system sub-models. However, it would be nonsense to try a simulation without a water balance (or surrogate). The simulation would fail due to lack of information for other modules. It is possible to create this invalid system in APSIM but it is destined to fail due to specification inadequacies.

In short, APSIM will allow the coupling of models from separate research efforts but it is up to the designers and users of the sub-model to ensure that it will operate correctly as a component of the system described in conjunction with other APSIM modules.

For further information about APSIM, check out our APSIM-Support help page.

APSIM Access & Pricing Policy

The Agricultural Production Systems Research Unit (APSRU) has released its new APSIM (Agricultural Production Systems sIMulator) Access and Pricing Policy, effective from 01 July 2003.

The Policy details APSRU’s principles of access to APSIM and the associated licence categories.  In addition the document provides information on the annual licence fees, training in APSIM and the availability of APSRU expertise and knowledge.

The use of APSIM will be subject to an agreement between APSRU and the user.

Some important changes for those wanting access to APSIM include:

·        APSIM will be now universally accessible for educational and non commercial research purposes

·        APSIM users must contribute to the ongoing costs of APSIM development including client support and upgrades through an annual  licence fee.

For more details please refer to the APSIM Access and Pricing Policy document. A copy of the APSIM Licence Application and a Sample Licence Agreement are also included for those wishing to apply for access to APSIM.