Journal of Applied Horticulture. 2003: 5(1): 3-6

Interactive effect of irrigation and fertilization on the quality of apples

L' ubomir, H

Slovak Water Management Enterprise, S.P., Irrigation and Drainage Branch Office, Vrakunska 29, 82563, Bratislava 211, Slovakia.

Experiments were conducted during 1999 and 2000 in Bratislava, Slovak Republic to evaluate the effects of different irrigation and fertilizer treatments on the quality of apple cultivars Gala, Jonagold and Idared. The treatments were: (A) liquid fertilizer (80 kg N, 80 kg P2O5 and 125 kg K2O/ha) combined with irrigation (fertigation); (B) liquid fertilizer (120 kg N, 80 kg P2O5 and 125 kg K2O/ha) combined with irrigation (fertigation); (C) solid fertilizer (80 kg N, 80 kg P2O5 and 125 kg K2O/ha) with irrigation; and (K) control, solid fertilizer (80 kg N, 80 kg P2O5 and 125 kg K2O/ha) without irrigation (atmospheric precipitation only). An increased rate of N (120 kg/ha) resulted in bigger shares of Selective and Class I grade fruits. A similar effect was produced by drip irrigation and typical response of individual cultivars was confirmed. In 1999, the share of Selective grade fruits by Gala was 93.3% in the non-irrigated treatment, which declined to 39.59% in the following year. An increased rate of N and complementary irrigation favourably influenced the initiation of flower buds and the variation of yields was reduced. Drip irrigation combined with an increased rate of N considerable influenced the yield and the varietal effect of the cultivar was observed on the responses. From the viewpoint of fruit quality, Jonagold showed the best response to regular irrigation and fertigation with N at 80 kg/ha. In the first year, the quality of fruits of Idared was homogeneous in all treatments, but better results were observed in the next year due to fertigation. The results achieved in the sensory, chemical and physical analyses of stored fruits of the tested cultivars showed the negative impact of increasing N rate. Averaged in all treatments, Gala produced 36.2 t/ha in 2000 and 10.5 t/ha in 1999; Jonagold produced 18.3 t/ha in 2000 and 30.5 t/ha in 1999; and Idared produced 35.3 t/ha in 2000 and 8.9 t/ha in 1999.