THE EFFECTIVENESS OF DIFFERENT CULTURE MEDIA FOR THE PRODUCTION OF GREENHOUSE TOMATOES
Many research workers (Penningsfeld, Puustjärvi, Pudelski, Starck, Hoffman, Oszkinis and Haber, Wood) are interested in the less decomposed peat and to a smaller degree in the pure muck as a greenhouse growing medium. In Poland 90% of the organic soil are muck. Muck is sold at a low price.
An experiment for growing glasshouse tomatoes on peat and muck substrates was conducted in 1968. With the spring crop steamed and not steamed greenhouse soil was compared with peat and muck treated in the same way. Both these organic media were used in two ways - in ground beds of a 35 cm thick peat layer and in form of "ring cultures" containers. The method of preparing ring cultures was based on the publication of Sheldrake and Dallyn, with one modification, viz.: the wooden laths, separating the peat beds from spaces between beds, substituted by 15 cm deep excavations in the ground (fig. 1). These 15 cm deep excavations in the ground of the greenhouse were laid out with 0.1 mm thick plastic sheets on which the peat serving as basis for the "rings" was piled. Spaces between beds were lined with plastics as well, to protect the plants from infestation with soil pathogenes. These so called rings are cuttings of plastic sleeves, being filled with peat; their diameter is 20 cm (fig. 2).
All experiments were conducted with the F1 hybrid Eurocross BB.
The reaction of all media was brought to the pH level 5.8–6.0. The fertilization of all media consisted of the addition of the MIS II mixture, containing N, P, K, Mg at the ratio of 1 : 2 : 2 : 0.3 in the amount of 3 kg/m3 and the microelements Fe, Mn, Cu, B, Mo and Zn in the amount of 130 g/m3.
Fertilization based on results of soil analysis after the Spurway method. The content of N-350, of P-400 and of K-600 mg/liter was considered as optimal. Nutrients were added as solutions.
Each experimental lot was repeated three times, each 10 plants per plot and each 12 in ring cultures.
The tomatoes in the experiment for spring harvest were sown on December 3, pricked out in flats on December 17, transplanted in plastic pots on January 5 and set on January 30. Until plant setting additional illumination with electric light of 4000 Lux was used.
Setting of the plants into the ground beds and as ring cultures was done in 2-row bands of plants per 1 m2 at the distance of 90/50/35.
The temperature of the glasshouse was regulated automatically at