The effect of potassium fertilization on the content of macroelements in potato tubers

Abstract

Potassium fertilization contributed to the reduction of total nitrogen and magnesium content in the tubers, while the increase in the K: Mg and K: (Ca + Mg) ratio did not affect the accumulation of nitrate, phosphorus, sodium and calcium. The results of the research were based on field experience, conducted in 2012-2014 in Parczew, on fawn soil with a slightly acidic reaction. The research facility was an average early, edible variety of Irga. The experiment was based on randomized three-repetition blocks. The potassium fertilization in the amount of 0, 35, 70, 105, 140, 175 and 175 kg K ha-1 was used as a potassium sulphate with a content of 42% K. They were applied on the basis of constant nitrogen-phosphate fertilization (80 kg N, 36 kg P ha-1). Phosphorus fertilizers and half the nitrogen dose were used before potato planting. The second nitrogen dose was applied at the beginning of flowering of the plant. Potatoes were grown on manure at a dose of 25 Mg ha-1, which was brought in the fall. Priced spring barley. Plot area for harvesting was 15 m2. After harvest, tuber samples were taken to evaluate their chemical composition. To determine the macronutrient content, tubers were crushed and then dried and the dry matter content was determined. This was then mineralized in concentrated sulfuric acid and potassium, calcium and sodium were determined by flame emission spectrophotometry (ESA); magnesium was determined by atomic absorption spectroscopy (ASA); phosphorus was colorimetrically determined by the vanadium-molybdenum method; nitrogen was determined by the Kjeldahl method. Ingredient content was calculated on absolutely dry basis, which was determined after drying. Relationships between mineral components contained in tubers were expressed as equivalents (K, Ca and Mg) and molar (Ca, P). The equivalence ratios were calculated based on the content of components expressed in g kg-1 DM and their equivalents (+). The results of the study were analyzed for variance (ANOVA).