ISHS Acta Horticulturae 221: Symposium on Horticultural Substrates and their Analysis
WATER POTENTIAL IN THE SUBSTRATE-SOLUTION SYSTEM IN HORTICULTURE |
| Author: | S. CHARPENTIER |
| Abstract:
The a priori determination of the water consumption of cultures on substrates with fertilizing irrigation must take into consideration not only the climatic parameters of the leaves' environment but also the physico chemical parameters of the roots' environment. Many plants have a production of fresh matter which reacts in adding up matric and osmotic components of the water potential, the distinction between these two components enabled us to bring to former very different variations of their size between peat based substrates and completely mineral substrates like rockwool. The proposed model formulates a process where the frequency and the dose of irrigation, the rate of draining off and the nutrient solution concentration could be varied. Results were in accordance with techniques observed in practice of growing plants on substrates. They confirm the possibility of avoiding salinity problems on peat based substrates with an appropriate draining off rate and the necessity of some leaching on rockwool where the control of water consumption is done with the osmotic component of its potential. The use of other relations like that between partial oxygen pressure in solution and temperature or between the withdrawal of nutrients by the plant and partial oxygen pressure could refine a model of water consumption by plants growing on substrates. | |
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