The CENTURY version 5 agroecosystem model is the latest version of the soil organic model developed by Parton et al. (1987). This model simulates C, N, P, and S dynamics through an annual cycle over time scales of centuries and millennia. The producer submodel may be a grassland/crop, forest or savanna system, with the flexibility of specifying potential primary production curves representing the site-specific plant community. CENTURY was especially developed to deal with a wide range of cropping system rotations and tillage practices for system analysis of the effects of management and global change on productivity and sustainability of agroecosystems.

Version 4 of the model integrated the effects of climate and soil driving variables and agricultural management to simulate carbon, nitrogen, and water dynamics in the soil-plant system. Simulation of complex agricultural management systems including crop rotations, tillage practices, fertilization, irrigation, grazing, and harvest methods is now possible.

Version 5 includes a layered soil physical structure, and new erosion and deposition submodels. The model code has been rewritten in C++, reorganized, and modified to use platform-independent configuration and output files. Added to this version is graphical-user interface providing ease of configuration and running CENTURY simulations, the Century Model Interface.

The CENTURY model embodies our best understanding to date of the biogeochemistry of carbon, nitrogen, phosphorus, and sulphur. The primary purposes of the model are to provide a tool for ecosystem analysis, to test the consistency of data and to evaluate the effect of changes in management and climate on ecosystems. Evolution of the model will continue as our understanding of biogeochemical processes improves. The identification of problem areas where processes are not adequately quantified is key to further developments. Ideally, model application will lead to the identification of needed research and new experimentation to improve understanding.

We value the responses and experiences of our collaborators in using CENTURY and encourage their feedback on problems in the current model formulation, as well as insight and suggestions for future model refinement and enhancement. It would be particularly helpful if users would communicate such feedback informally and where possible share with us documented model applications including manuscripts, papers, procedures, or individual model development.

Where to Go Next

Introduction to Century
Soil Organic Matter Submodel
Water and Temperature Submodels
Nitrogen Submodel
Phosphorus Submodel
Sulfur Submodel
Plant Production Submodels
Labeled Carbon (14C and 13C)
Enriched CO2 Effects
Soil Incubation (Microcosms)
Weather Data
Parameterization of the Model