Mizuna (Brassica rapa L. var. japonica) was grown in a greenhouse experiment conducted in the Experimental Garden at the Faculty of Agriculture and Forestry, University of Warmia and Mazury in Olsztyn, in 2017-2018. The experiment had a completely randomized block design. The experimental variables were as follows: (i) two mizuna cultivars: red and green, and (ii) two types of organic substrate: coco coir based substrate and peat. Mizuna plants were grown in 0.5 dm3 pots placed on movable flood tables; 20 seeds were sown per pot. Edible plant parts were harvested at maturity. The concentrations of the following macronutrients and micronutrients were determined in mizuna leaves: total nitrogen (Ntotal), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), sulfur (S), copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn). The following ratios were also calculated: Ca:P, Ca:Mg, K:Mg, K:(Ca+Mg), K:Ca, N:S, Fe:Mn, Fe:Cu, Zn:Cu, Mn:Zn and Mn:Fe. The yield of fresh mizuna leaves grown in the peat substrate was about 80% higher than that in the coconut substrate. Red cultivar plants had a significantly higher leaf greenness value expressed by the SPAD index. More Ntotal, K and Mg was contained the leaves of mizuna grown in the peat substrate. The edible parts of mizuna grown in coconut substrate were more abundant in P, Ca and S. It was found that the red mizuna leaves in this experiment had a higher content of Ntotal, P, K and S, while the green mizuna leaves had a higher content of Mg and Ca. The proportions of K: (Ca + Mg) and N: S in the mizuna leaves were optimal, Ca: Mg, K: Mg and Ca: P were too wide, and the K: Ca ratio too narrow. The micronutrient concentrations were higher in the red mizuna leaves than in the green mizuna ones. The leaves of the plants grown in the peat substrate had a higher content of Cu, Fe, Zn and Mn compared to the plants grown in the coconut substrate.

26.4.2021