Abstract

With its sophisticated technical systems the modern greenhouse of today implies major investments for the greenhouse nursery. Maximum utilization of the production equipment and high efficiency is therefore necessary. Computers offer a more efficient way of controlling and monitoring the production processes than was previously possible. So for; it has been the greenhouse climate that has been in focus for computerized control. However; by developing mathematical models describing various aspects of biological growth and development the potential is created for computerized control of plant growth, development, spacing, and other production processes. This report shows that computerized control of the development of a pot plant is possible. A control algorithm was developed based on an existing model describing the floral development of Cineraria (Senecio x hybridus (Hyl.) 'Molls stam'. In simulations and experiments the floral development was controlled by changing the greenhouse climate. The extent of the climate changes was based on comparisons between desired and actual development. The experiments showed that crop development could be controlled with a high precision. Furthermore, computer simulations indicated that it is possible to use adaptive regulators in future strategy for controlling crop development. The potential of digital image analysis for identifying stages of crop development and growth was also studied. In theory this should make automatic monitoring and control of the growth processes possible. For identifying Cineraria’s floral development the relation between percentage of flower colour and registered stage of floral development was investigated. However the experiments showed that this approach could only be used during the end of the cultivation period. For precise identification of earlier stages of development more advanced technique and equipment is needed than those adapted. Further investigations of image analysis showed that the studied equipment could be used to monitor the growth of the plant canopy in terms of horizontal expansion. A model was constructed defining the relation between plant density, plant diameter and bench area covered by the crop canopy. By measuring the plant diameter with the image system and by determining a desired area covered by the crop canopy, it is possible at any time to calculate a desired plant density. A further model was now developed making it possible to predict the time of spacing of the pot plant crop in relation to canopy growth. Experiments showed that this model made acceptable predictions. Combined, the two models make it possible to use image analysis as a means of monitoring the process in an automatic spacing system.

Keywords

reglering; blomutveckling; växthus; bildanalys; glesning; matematisk modell

Published in

Rapport - Sveriges lantbruksuniversitet, Institutionen för lantbruksteknik
1992,
Publisher: Institutionen för lantbruksteknik, Sveriges lantbruksuniversitet

Permanent link to this page (URI)

https://res.slu.se/id/publ/125605