ISHS Acta Horticulturae 396: Hydroponics and Transplant Production
EFECTS OF CLOSED SYSTEMS IN SUBSTRATE CULTURE FOR VEGETABLE PRODUCTION IN GREENHOUSES |
| Author: | M. Böhme |
| Keywords: | Closed systems, Cucumber, Drainwater, Greenhouse, Hydroponic, Nutrient solution |
| Abstract:
For reasons of ecology, transition to closed systems will be common practice also in hydroponic substrate culture. Recycling of surplus nutrient solution raises questions regarding the disinfection of the drainwater and the changes occurring in its composition. In substrate culture with drip irrigation, unlike in systems with recirculating solution (e.g. NFT), surplus spent solution does not come up in constant quantities. The effects of different amounts of surplus solution (between 1 and 45 per cent) should be taken into account when designing the scheme of plant nutrition. Hence, a different approach has to be followed for compounding the nutrient solution in the course of crop cultivation. An experiment with greenhouse cucumber and different kinds of substrate is used to show the amounts of nutrient solution applied at various stages of plant growth, and the losses that occurred. From the analysis of the nutrients lost, conclusions can be drawn for compounding the recycled solution. The chances and problems associated with the introduction of completely closed systems in substrate culture should be discussed in the light of plant health and ecological compatibility. | |
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