There was a download of ORYZA2000 3.0 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. We recommend checking the downloaded files with any free antivirus. The program belongs to Education Tools. Commonly, this program's installer has the following filename: ORYZA_V3.exe. The most popular versions among the program users are 3.0 and 1.0. This free software was originally created by International Rice Research Institute.
From the developer:
ORYZA is an ecophysiological model which simulates growth and development of rice including water, C, and N balance in lowland, upland, and aerobic rice ecosystems. It works in potential, water-limited, nitrogen-limited, and NxW-limited conditions. And it was calibrated and validated for 18 popular rice varieties in 15 locations throughout Asia.
You may want to check out more software, such as StatPlus 2007, Avantage BPM Foundation or Adding Machine, which might be similar to ORYZA2000.