Hydroponic systems are very often used for tomato production in the greenhouse. An important role in the diagnosis of a plant nutritional status is played by leaf analysis. Boron toxicity is crop specific, manifesting itself as damage to the tissues where it accumulates, and generally leading to chlorosis and necrosis, first at the edges of mature leaves. The aim of the study was to assess the effect of varying boron levels in the nutrient solution used for fertigation of two tomato cultivars (Alboney F1  and Emotion F1), supplied in the form of boric acid and borax. A plant-growing experiment was conducted in 2009 – 2012 (Experiment I) and 2013 – 2014 (Experiment II). A standard nutrient solution for tomato cultivation was used with the following nutrient content (in mg·dm-3): N-NH4 – 2.0, N-NO3 – 230, P – 50, K – 420, Ca – 140, Mg – 60, Cl – 30, S-SO4 – 120, Fe –1.80, Mn – 0.3, Zn – 0.50, Cu – 0.07. The following combinations were tested (mg·dm-3): Control (0.011), 0.4, 0.8, 1.6 in the form of: Na2B4O7·10H2O (Experiment I) and boric acid H3BO3 (Experiment II); (combinations denoted by the symbols B-I, B-II, B-III, and B-IV, respectively). Analyses were conducted on the effect of boron fertigation on the macro- and micronutrient content in leaves of tomato grown on rockwool. Supplied boric acid, the variety significantly differentiated the content of phosphorus (B-III and B-IV), potassium (B-III), magnesium (B-I to B-IV), iron (B-I and B-II), zinc (B-I and B-III), copper (B-IV). When standard borax was used, the variety modified the content of potassium (B-IV), calcium (B-I and B-IV), magnesium (B-I and B-II), iron (B-III), manganese (B-I to B-IV), copper (B-IV).  

24.2.2019