The Reaction of Winter Oilseed Rape to Different Foliar Fertilization with Macro- and Micronutrients

Foliar fertilization provides cultivated plants with the necessary nutrients during the growing season. The conducted field experiment was aimed at comparing the effectiveness of different variants of foliar fertilization applied in the cultivation of winter oilseed rape (<i>Brassica napus L.</i>), cultivar ‘ES Cesario’. The experimental factors were: A (control), B (YaraVita Brassitrel Pro), C (YaraVita Brassitrel Pro and YaraVita Thiotrac), D (YaraVita Brassitrel Pro and YaraVita Bortrac), E (YaraVita Brassitrel Pro and YaraVita Bortrac and YaraVita Thiotrac) and F (YaraVita Thiotrac). Weather conditions were variable over the years of the study and had a modifying effect on most of the tested parameters. Intensive foliar fertilization (variants D and E) resulted in a significant increase in the number of pods per plant, seed and fat yields, and SPAD (soil plant analysis development) and LAI (leaf area index) indices compared to the control. The protein yield was the highest after fertilizer applications in variants C and E. The use of YaraVita Thiotrac alone (variant F) did not provide the expected results. Foliar fertilizers applied in variant D increased Gs (leaf stomatal conductance) measurements and fat content in seeds but decreased TSW and seed protein content. It was shown that intensive foliar fertilization (variants D and E) increased seed boron content compared to YaraVita Thiotrac fertilization and the control. Fat and protein yields were strongly positively correlated with seed yield (r = 0.93 and r = 0.71, respectively). The best economic effect was obtained after applying foliar fertilization in variants D and E; therefore, they can be recommended for agricultural practice.