In Poland, the Welsh onion is still grown on a small scale only, while it is widespread and broadly used in the Far East. Owing to their mild, sweet flavour and delicate consistency, whole Welsh onion plants are used as ingredients in various dishes. Recent years have witnessed the growing popularity of Welsh onions in the Polish cuisine, particularly as a spring seasonal item. A two-factorial field experiment in a randomized block design with replications was performed in 2010 – 2012 in the Experimental Garden of the University of Warmia and Mazury in Olsztyn (NE Poland). Seeds of three Welsh onion cultivars, Long White Ishikura, Parade and Performer, were used. The aim of the study was to determine the effect of Polimag S fertilizer applied at different doses on the yield and the nutritional value of the edible parts of Welsh onion plants. The experimental factors were: (1) Welsh onion cultivars Long White Ishikura, Parade and Performer grown from seedlings, and (2) the application of a mixed fertilizer, Polimag S, at two doses of 0.72 t ha -1 and 1.44 t ha -1. The Welsh onion cultivars analyzed did not differ significantly with respect to yield. The total yield of Welsh onions did not increase significantly as the dose of Polimag S was increased from 0.72 t ha-1 to 1.44 t ha-1, which indicates that increased fertilizer use was economically unjustified. In all the years of the study, the lowest Welsh onion yield was obtained in the control treatments. Welsh onions cv. Performer had the highest dry matter content. Welsh onion cultivars and Polimag S had varied effects on the nitrate accumulation in the plants, but the maximum permissible nitrate levels were not exceeded. According to the current Regulation of the Minister of Health of 22 December 2004 the content of heavy metals in Welsh onion was lower than the normal range.

21.3.2016