The study was conducted on the basis of a multiannual static field experiment established in 1979. It was conducted in the 3-year simplified rotation system: potato – winter rye – winter rye. The study refers to an early, edible variety of Bila potato growing in the first year of 10^th rotation (2006). Experimental factors were the following: organic fertilisation (without manure and with manure 30 t·ha^-1), and nitrate fertilisation – four doses (0, 60, 120, 180 kg∙ha^-1). The aim of this study was to define the influence of organic and mineral fertilisation on selected qualitative properties of potato tubers. The results obtained from the study show a positive effect of manure and nitrate fertilisation on dry matter and starch content and a negative effect on sugar content. Increasing nitrogen doses lowered a content of vitamin C in potato tubers. However, potatoes growing on manure had a higher content of this ingredient.

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