Studies were conducted with tomato of Admiro F₁ cultivar grown in greenhouse in the years 2008 and 2009. Four substrates were applied: 1) rape straw, 2) rape straw + high peat (3 : 1 v:v), 3) rape straw + pine bark (3 : 1 v:v), 4) rockwool (100 × 20 × 7.5 = 15 dm³). Straw, cut into pieces, (2–3 cm), were placed in plastic boxes (height of the box ca. twice large as width) of the capacity of 15 dm³. In each box/slab there grew two plants. The experiment was conducted using the complete randomization method in seven repetitions. Dripping fertigation was applied in a closed system without nutrient solution recirculation. Daily nutrient solution consumption was once up to 4.2 dm³ in 10–12 doses with about 20% overflow. In the conducted studies it was demonstrated that the cut rape straw is a very good substratum for greenhouse grown tomato. Higher fruit yields were obtained from growing in rape straw + pine bark substratum compared to rockwool, and the differences were not significant. The dry matter content in fruit grown in organic substrata was significantly higher compared to rockwool. The content of N-total in fruit grown in rockwool was significantly lower compared to organic substrata. During tomato vegetation about 60% rape straw was mineralized.

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