The effect of nitrogen fertilization on yield and macronutrient concentrations in root chicory (Cichorium intybus L. var. Sativus Bisch) and the health status of plants

The effect of N fertilization on the health status of chicory plants, yield and the content of dry matter and macronutrients in chicory roots was determined in the study. Three root chicory cultivars, Polanowicka, Orchies and Chrysolite, were grown in a plot experiment. Three levels of topsoil N fertilization were applied before sowing: 0, 80 and 120 kg ha–1. The severity of leaf diseases was estimated during the growing season. Root yield, agronomic and marginal N-use efficiency, DM content and macronutrient concentrations in roots were calculated after harvest (10–20 October). The symptoms of powdery mildew, gray mold and leaf spot on chicory leaves were significantly least severe in the unfertilized treatment. The highest yield (83 Mg ha–1) was obtained in 2017, in cv. Chrysolite without N fertilization. Root yield decreased in response to the application of N fertilizer at both rates. A minor increase in yield was observed only in cv. Polanowicka in N-fertilized treatments in 2017, and in cv. Chrysolite fertilized with 80 kg N ha–1 in 2018. Root yield was negatively correlated with disease severity during the growing season. The DM content of chicory roots (mean values for years of the study, cultivars and N rates) was similar in all treatments. N fertilization induced changes in the content of N, K, Mg and S in chicory roots of the analyzed cultivars. The application of N fertilizer had a beneficial influence on the N content of roots in all cultivars.