THE INFLUENCE OF THE O2-CONCENTRATION IN THE NUTRIENT SOLUTION ON THE DEVELOPMENT OF CUCUMBER-PLANTS IN A SPECIAL HYDROPONIC-SYSTEM.

O. Fölster
The soilless cultivation of crops in glasshouses has become more important during recent years. The reasons are difficulties in keeping the soil healthy and the trend to mechanize and automatize plant culture. Further more the recent industrial production of fully water-soluble compound fertilizers makes the mixing of the nutrient solution simpler and the use of the hydroponic for the farmer easier. The success of the hydroponic depends on an optimal nutrient supply and nutrient relationship as well as on the adherence to the necessary pH value and O2-concentration of the solution. About the minimum or optimum O2-concentration in the solution for successful cropping there is little information. Hence we tested the influence of the O2-concentration in the nutrient solution on the development and yield of cucumber plants by using an almost fully automatic hydroponic-system.

Figure 1 shows the scheme of the hydroponic-system we used. Normal plastic tubes of 15 cm diameter, in which holes for the plants were drilled, were put together like a harp. In these tubes the nutrient solution was circulated twice an hour by a pump to avoid gradients of the nutrients or CO2, and to enrich the nutrient solution again with O2. The O2-enrichment was carried out by spraying the nutrient solution in short vertical tubes. As the O2-enrichment was not high enough the solution was additionally aerated by pressed air. The value of the nutrients in the solution was checked by an outlet of used and inlet of fresh nutrient solution. The outlet was controlled by conductivity measurements and a magnet-ventil, the inlet by a niveau controller and a small pump. The nutrient solution was obtained by two water jet pumps mixing two concentrated solutions with water in a relationship of 100 : 1.

As far as possible the nutrient solution was dispensed by industrially produced fully water-soluble compound fertilizers.

Fölster, O. (1974). THE INFLUENCE OF THE O2-CONCENTRATION IN THE NUTRIENT SOLUTION ON THE DEVELOPMENT OF CUCUMBER-PLANTS IN A SPECIAL HYDROPONIC-SYSTEM.. Acta Hortic. 37, 2046-2050
DOI: 10.17660/ActaHortic.1974.37.18
https://doi.org/10.17660/ActaHortic.1974.37.18

Acta Horticulturae