ISHS Acta Horticulturae 148: III International Symposium on Energy in Protected Cultivation
SYSTEM IDENTIFICATION OF PLANT RESPONSES IN ENERGY CONSERVATIVE GREENHOUSES |
| Authors: | Y. Hashimoto, B.R. Strain, T. Morimoto, T. Fukuyama |
| Abstract:
Appropriate control of environment in greenhouses consists in precise evaluation of plant responses to environmental changes and of energy conservation. In this connection, we propose an approach of system identification as a way of this control. A system was set up in which environmental factors in greenhouses were employed as input data and plant responses as output data, where plant responses could be called "speaking plant", and system identification was examined by non-parametric spectral analysis. It was revealed that responses of plant (tomato)-in leaf temperature and photosynthetic rate-to diurnal changes in solar radiation can be expressed by linear filtering through impulse responses determined by spectral analysis. Furthermore, adaptability to diurnal changes in solar radiation seems to be one of the major characteristics of plants growing in greenhouses. It was also revealed that plant responses to temperature changes, which were caused by on-off of hot water circulating in the heating pipes for night heating, can be evaluated by a similar method. This method enables the preestimation of plant responses to various environmental changes, thus providing a prospect of effective control of environment in greenhouses by appropriate evaluation of plant responses and of energy conservation. | |
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