An object-oriented and web-based simulator for plant growth

An object-oriented plant growth simulator was developed for research and educational purposes. Its source code consisted of MODEL and IO packages, as well as Java applet Simulator and classes for designing user graphical interface. The MODEL package included Java object classes coded for fundamental plant growth processes, state-variables, environmental factors and cultural practices based upon agronomic theory, experimental data, and published models. The IO package contained Java classes which deal with input and output problems. The source code is portable and reusable for further development and other crop modeling work. Plant, Weather and Soil databases were developed to input data and run the Java program. The plant database contains 14 sets of plant species data, while the weather database has 8 years of local weather data, and the soil database gives examples of soil characteristics for three representative soil-types upon which the plants might be grown. These three databases, managed by Microsoft Access, have been connected to the Java program using Java Database Connectivity as bridges. The program was developed as a Java applet with a user-friendly graphical interface running on the Web. With a Java (JDK1.1)-embedded web browser such as Netscape Communicator 4.5, Microsoft Internet Explorer 4.5, etc., users can link the run-time model and run plant growth simulations on their client machine with code from our website. They can choose a target plant species and select different weather and soil conditions from the menu choices built-into the interface, and then input agronomic data using a popup window or the relevant text fields. The output is then displayed in both graphical and text forms chosen from a popup menu for such state-variables or processes as plant height, LAI, biomass, etc. The program describes the growth of a typical plant that is free of pests and diseases. It is currently able to simulate plant growth for more than a dozen crops and weeds under Illinois weather conditions using properties of three typical soils.