| Opis: | Four apple (Malus domestica Borkh) cultivars grafted on M9 rootstock were grown at high density ('Elstar' and 'Jonagold' 2500 trees/ha, 'Idared' and 'Golden Delicious' 3000 trees/ha). There five treatments for each cultuvar (fertirigation with 45 kg N/ha, 60 kg N/ha, 120 kg N/ha, irrigation without fertilisers, and control - without irrigation and without fertilisers), and two timing variants (treatments during vegetation period from 1 May - 20 June - variant A, and treatments from 1 May to 1 August - variant B). The treatments were imposed beginning in the third year after planting and lasted three years (1993-1995). It was found that the intensity of effects of fertirigation upon vegetative growth and cropping of individual cultivars varied. To a certain extent 'Elstar' and 'Jonagold' responded similary to treatments. It was proved that most positive effects of fertirigation were achieved at the dosage of 45 and 60 N/ha during vegetation period, and at 120 kg/ha in treatments up to the start of flower buds differentiation. Cultivar Idared was not responded to fertigation and irrigation up to June 20, but during the vegetation period the bestresults were obtained at 45 kg N/ha. The response of 'Golden Delicious' to fertirigation durin vegetation was similar as 'Idared', but most positive effects of fertirigation for this cultivar wer, similary as for 'Elstar' and 'Jonagold' achieved at 120 kg N/ha when fertirigation was applied to June 20. Cultivar 'Idared' showed the best yield performance and the highest yield/ha, whereas 'Elstar' gave the most unfavourable results. |
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