A modular soil and root process simulator

The ability to build models for various crop management scenarios can be enhanced by using modules corresponding to soil, root atmosphere and management processes. In this paper we describe the design of a generic modular soil and root process simulator (2DSOIL) for use in crop modelling. Coded in Fortran 77, it uses a three-level hierarchy to organize soil processes and their parameters into a modularized structure. Decoupling of processes and re-arrangement of boundary condition formulations are used to facilitate independence of modules and the encapsulation of information is consistently implemented. Variable time steps are selected using restrictions imposed by non-linearity of models. The use of this modular design allows modellers to reuse well-tested codes, and results in a decrease of effort in input data preparation and in expandability to encompass various management practices. The modular design of 2DSOIL allows it to be readily modified and easily incorporated into crop models.