Development of a Simple Model to Simulate Growth of Tomato in a Green House.

Tomato is usually grown in a greenhouse where microclimate conditions are usually controlled. Simulation of tomato growth using a crop model would be useful to optimize climate conditions within a greenhouse. The objective of this study was to develop a simple model for simulation of tomato growth in a greenhouse based on the energy balance principle. The simple model consists of modules for calculation of radiation transfer, energy balance within a greenhouse as well as photosynthesis and phenology of the crop. In simulation of energy balance in the greenhouse, optical characteristics of building materials, e.g., glass, were considered. For simulation of photosynthesis, leaf temperature obtained from energy balance equation was used. Using air temperature within the greenhouse, growing periods and flowing timing were also determined. The model was designed to provide the simulation outputs through memory in order to interface with a controller of greenhouse for optimum conditions, e.g., ventilation, shading or warming. The concepts of energy balance as well as crop growth were implemented in a simple form, which would faciliate integration of the model into the programmable controller. As a prototype, the model was writen in python, which would make it easy to translate this model into another high level of computer programming languages, e.g., C or java, that would be compatible with a greenhouse controller.