Chemical composition of cherry fruit from the cultivars Kelleris 16 and Lutowka depending on different water conditions and fertilization

The research was conducted in 2011-2012, at the Experimental Station in Lipnik near Stargard Szczeciński, on soil classified as Haplic Cambisol, with low useful water retention. The experiment was designed with a split-plot method and repeated seven times. Grass cover was maintained in the row middles while the area underneath the trees was kept as herbicide fallow. The trees were planted in 4x2 m spacing. The assessment concerned the influence of irrigation and NK fertilisation on the dry matter and chemical composition of cherry fruit from the cultivars Kelleris 16 and Łutówka. Micro-irrigation was used at water potential in soil lower than 0.01 MPa. According to agronomic recommendations, nitrogen fertilizers were applied in early spring and potassium fertilizers in autumn in the following doses: 0 NK (control, no fertilization), 1 NK – 80 kg.ha-1 (40+40), 2 NK - 160 kg.ha-1(80+80), according to agronomic recommendations. Ammonium nitrate containing 34% of nitrogen and potash salt containing 60% of potassium were used for fertilization. Observations of the irrigated trees showed an increase in the dry mass in their fruit, as well as a decrease in nitrogen, potassium and magnesium concentrations, but an increase in the amount of calcium. Chemical analyses of the fruit harvested from the trees fertilized with nitrogen and potassium demonstrated an increase in the analysed traits (macro- and micronutrients), at both 1NK and 2NK fertilization levels.