Profit Models Based on the Growth Dynamics of Lettuce Populations in a Plant Factory

Abstract

A profit model provides a guideline for facility construction and management of plant factories. Practically, the model depends on plant growth conditions and shipping type in each plant factory and these parameters should be optimized. However, the profit model has not been studied well. In this study, we focused on plant growth dynamics and three shipping types. A mathematical model of growth dynamics describes the time change of average and distribution of fresh weight from nursing to harvesting. The parameters of the profit model were investigated based on experimental data in a commercial plant factory. In the experimental results, the yield was strongly dependent on the growth dynamics of the lettuce population. From the sensitivity analysis of each parameter, it was clarified that the quality of seedling and the cultivation days are mostly effective for profit as high priority parameters. Our results suggest that it is important to regulate the growth dynamics at early stages (young seedling stage) and cultivation days in order to maximize profit in plant factories.