Several studies conducted at present concern the application of biostimulants in intensive plant growing. Titanium is an element exhibiting characteristics of a biostimulant. The aim of the conducted analyses was to evaluate the effect of the application of titanium on plant nutrition, their yielding as well as contents of macronutrients and biological value of fruits in tomato grown on rockwool. The following levels of titanium were analysed: the control (no titanium applied), Ti-I (corresponding to an annual dose of 80 g Ti·ha^-1), Ti-II (240 g Ti·ha^-1), Ti-III (480 g Ti·ha^-1) and Ti-IV (960 g Ti·ha^-1). The source of titanium was “Tytanit” fertilizer (Intermag Olkusz). In the conducted study a significant effect of titanium application was found at the Ti-IV level on the produced total and marketable yields, at the simultaneous increase in the yield of fruits with the greatest diameters (classes I, II and III) in comparison to the other tested combinations. A significant effect of Ti was found on an increase in contents in the index parts of plants in case of nitrogen, phosphorus, calcium and magnesium (the greatest contents of N, P, Ca and Mg recorded at Ti-IV) as well as potassium (the highest content at Ti-I). A general trend was observed (except for Ti-II) for an increase in nitrogen content in fruits under the influence of titanium application, at a simultaneous lack of effect on contents of phosphorus and potassium. In case of calcium and magnesium the recorded changes were multifaceted. No significant effect of titanium was observed on contents of dry matter and sugars in fruits, as well as their active acidity. At the same time a significant variation of vitamin C contents in fruits was recorded, depending on the level of titanium nutrition of plants.

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