Welcome to ORYZA2000, Version 2.12 - November, 2004

Crop modeling and systems analysis have become important tools in modern agricultural research. A crop model synthesizes our insights into the physiological and ecological processes that govern crop growth into mathematical equations. Our understanding of crop performance is tested by comparing simulation results with experimental observations, thus making the gaps in our knowledge explicit. Experiments can then be designed to fill these gaps. Once a model is validated, it can be used to help analyze and interpret field experiments. It can also be used in application-oriented research such as the design of crop ideotypes, the analysis of yield gaps, the optimisation of crop management, the ex-ante analysis of the effects of climate change on crop growth, and agroecological zonation.

This package contains the model ORYZA2000 (Version 2.12, 2004), to simulate the growth, development and water balance of rice under conditions of potential production, water limitations, and nitrogen limitations. Version 1 of ORYZA2000 was published in 2001 and the integral text of the book (complete scientific description and user guide) is included here. The section Release notes describes the changes and additions made in subsequent versions: May 2003 (v2.0), January 2004 (v2.1), June 2004 (v2.11), November 2004 (v2.12).

The major changes are the:

• implementation of a user-friendly shell called FSEWin

• the inclusion of two new water balance models (SAWAH and SAHEL)

• first attempt to model upland and aerobic rice.

ORYZA2000 tutorial has been developed that guide users of ORYZA2000 through the FSEWin Shell, the parameterisation and running of the model (input and output data control), and the interpretation of model results. All software (FSEWin, ORYZA2000), data sets and exercises can be freely downloaded. Through this, readers are encouraged to experiment with the model and apply it in their own research. All ORYZA2000 materials are a joint product of the International Rice Research Institute and the C.T. De Wit Graduate School of Production Ecology and Resource Conservation of Wageningen University and Research Centre.