Nutritional Value of Parsley Roots Depending on Nitrogen and Magnesium Fertilization

Parsley is an herb/vegetable rich in nutritional compounds such as carbohydrates, vitamins, protein, crude fiber, minerals (especially potassium), phosphorus, magnesium, calcium, iron, and essential oils. Limited information is available in the literature on the quality of parsley roots depending on the cultivation technology used in the form of macronutrients and micronutrients, preparations to stimulate plant growth and development, as well as plant-protection products. A three-year study was undertaken to determine the effect of applying mineral fertilization with nitrogen, including magnesium on the nutritional value of parsley roots in terms of the content of ascorbic acid, total and reducing sugars, and minerals: (total N, K, Mg, Ca). The research material was the root of Petroselinum crispum ssp. tuberosum from an experiment where nitrogen was applied in soil at (0, 40, 80, 120 kg N ha −1 ) and magnesium at (0, 30 kg MgO ha −1 ). Nitrogen fertilization increased the nutritional value in terms of total and reducing sugars, as well as total N and Ca content. Applied magnesium fertilization caused a significant increase in the content of all tested nutrients. The most total sugars (127.7 g kg −1 f. m.), reducing sugars (16.8 g kg −1 f. m.), and total N (12.13 g kg −1 d. m.) were accumulated by roots from the object where nitrogen was applied at a maximum rate of 120 kg N ha −1 , including magnesium. On the other hand, for the content of K (19.09 g kg −1 d. m.) in the roots, a dose of 80 N ha −1 was sufficient. For ascorbic acid (263.2 g kg −1 f. m.) and Ca (0.461 g kg −1 d. m.), a dose of 40 kg N ha −1 with a constant fertilization of 30 kg MgO ha −1 was sufficient. When applying high doses of nitrogen, lower doses of magnesium are recommended. This is sufficient due to the high nutritional value of parsley roots. Due to the worsening magnesium deficiency in soils in recent years, the use of this nutrient in the cultivation of root vegetables is as justified and timely as possible. Quality-assessment studies of root vegetables should be continued with higher amounts of magnesium fertilization. Different ways of applying magnesium in parsley cultivation should also be tested.