The fact that the greenhouse has got fertigation equipment allows for taking apply of various organic materials as substrate. Organic substrata applied in greenhouse cultivations, as compared with rockwool, are biodegradable and as a post-cultivation waste not destroy the natural environment. This research was conducted in glasshouse in the years 2008–2009. The tomato of Admiro F₁ cultivar in the period from February to October for 22 clusters at the density of 2.4 plants for 1 m². The treatment consisted of four substrata: 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 cm = 15 dm³). Straw was cut into pieces (2–3 cm) and placed in boxes 14 cm high, width: 8 cm and capacity 15 dm³. During the growing period after 33 weeks about 60% straw has been decomposed. Drop fertigation was applied in a closed system, without nutrient solution recirculation. In the period cultivar of tomato only in the first weeks in organic substrata a decrease in mineral nitrogen content was reported (albumization), but in cannot affect the plant growth because every day nutrient solution was supplied to plants 9–11 times. The content of N-NH₄ , N-NO₃, K, Ca, Mg and EC in organic substrates did not significantly differ, compared to rockwool. in both study years. This experiment suggests that the nutrient solution for tomato cultivar in organic substrates was may be similar like that in rockwool.

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