The experiment was conducted in 2014-2016, on a farm located in western Poland. The aim was to evaluate the effect of foliar application of potassium sulphate (SOP) and micronutrients (Zn, Cu, Mn and B) on the content and accumulation of macroelements (N, K, Mg and S) in tubers at the stage of technological maturity. Two potato varieties tested in the experiment, Zorba and Hermes,  are used to produce French fries and crisps, respectively. Analyses involved data from four trials, including the control where solely NPK fertilisation was applied. The other trials included: (I) double foliar treatment with SOP in the combined dose of 8.6 kg K ha-1; (II) double foliar treatment with micronutrients: 12 g Zn ha-1, 12 g Cu ha-1, 300g Mn ha-1,and 500 g B ha-1, and (III) combined application of SOP and micronutrients on two scheduled terms. The experiment was arranged in a randomised block design with four replicates for each potato variety. The experimental factor differentiated the content and uptake of macroelements, being largely controlled by changing weather conditions. Averaged across the three study years, values of nutrient accumulation in tubers showed that foliar fertilisation with potassium and micronutrients enhanced tuber K accumulation. The increase in tuber nutrient accumulation owing to foliar fertilisation was higher in the crisps variety compared to the French fries one. The regression analysis showed that the tuber yield was in 65-87% controlled by the accumulation of macroelements (N, K, Mg and S). Moreover, the protein content in both varieties was largely determined by the accumulation of macroelements in tubers, while significant relationships for the starch content were noted only in the case of the Zorba variety.

25.3.2020