Articles
MANAGEMENT OF MICROBIAL FACTORS IN THE RHIZOSPHERE AND NUTRIENT SOLUTION OF HYDROPONICALLY GROWN TOMATO
In these systems, however, organic compounds and microorganisms may accumulate.
There is also an enhanced risk for spread of plant diseases.
Several methods for spot desinfection of the nutrient solution have been developed for the use in closed hydroponics.
The hydroponic system in front of and behind the desinfection device, however, is insterile.
As the main part of the microflora is attached to surfaces such as the gutter, root surface and substrate, our approach is directed towards the stabilization of the microflora in the nutrient solution and on the root by microbial means.
Management of microbial factors may be performed on different levels; on the root surface and inside the root by plant growth-promoting organisms, in the nutrient solution by microorganisms degrading plant growth-inhibitory organic compounds and in a microbiologically active slow sand filter, affecting nutrient solution-inhabiting microorganisms by various means.
Generally, both fungi and bacteria might be used.
Here, bacteria were chosen due to their colonization ability of the root and their compatibility to environmental conditions in the nutrient solution.
For the management of microbial factors, increased knowledge about the microbial background is of great interest.
Studies performed in commercial market gardens showed that there were seasonal changes both with respect to quality and quantity of bacteria on the root and in the nutrient solution. Pseudomonas was the predominant species.
The microbial dynamics in closed hydroponic systems is presently studied by metabolic and by phospholipid fatty acid profiles.