Evapotranspiration Model Analysis of Crop Water Use in Plant Factory System

Abstract

An estimation based on a mathematical model to predict hourly evapotranspiration (ET) rates that occur inside a plant factory system was made using the Stanghellini model. The Stanghellini model is considered more appropriate for estimating the rate of ET inside the soilless culture of greenhouse tomatoes. The model requires some climatic data (e.g., solar radiation, air temperature, relative humidity, and wind speed) and plant growth parameters (leaf area index) as inputs. In this study, the observed data were obtained from an experimental greenhouse located at the Ehime University, Japan. The ET rate of tomato (Lycopersicon esculentum Mill.) crop was measured using a weighing method. Accurate determination of ET is essential to precisely compute crop water use and to assist growers for applying good irrigation management. The results showed that solar radiation and vapor pressure deficit are important factors driving the ET rate. The model's output showed good results for determining the ET rate and depicted crop water requirements on an hourly basis.