Growth Promoting and Stabilizing of Cucumber Plants Cultivated in Soilless Cultivation Systems Using Biostimulators

Abstract

Cultivation of cucumber in greenhouses is predominantly carried out in soilless cultivation systems mainly in substrate culture. The use of organic and completely compostable substrates is of rising interest in such systems, unclean sheep wool was formed as substrate slabs, peat slabs and coconut fiber slabs were compared with mineral substrates rockwool and perlite. In general can be stated, intensively in greenhouses cultivated crops such as cucumbers, suffer often from inadequate abiotic or biotic growth conditions in particular in the rhizosphere. Many studies were done to find growth promoters or biostimulators to stabilize the growing condition in the rhizosphere, in case of stress situation as fluctuating salt concentration EC and pH value, but also in case of temperature stress. K-Humate, Lactate and Bacillus subtilis were investigated as biostimulators in such situations. Different concentration and combination of these biostimulators were investigated but also the methods of application on leaves and roots respectively. Very successful was used for the stabilization of the EC value for cucumber plants growing in substrate the application of K-Humate and B. subtilis (FZB24®) as single component and combined. Following the results, it can be assumed, the application of the combined biostimulators with all substances if applied over the roots was a stimulating effect visible, whereas if applied over the leaves an inhibiting effect for cucumber plant growth. Application of the biostimulators solution with all three components BS-FZB24® (0.2%), K-Humate (0.01%), and LACTOFOL “O” (0.1%) were tested regarding their effects in case of strong but short time pH and temperature stress the growth of cucumber plants. There are a strong correlation between green biomass of treated cucumber plants and their root mass. It can be assumed that one of the effects of stress prevention through the biostimulators is primarily based on increasing root growth.