Effect of Nitrogen Fertilization on Yield and Quality of Endive

The aim of the experiments carried out in 2007-2008 was to assess the effect of various nitrogen doses on the growth, yield and nutritional value of two endive cultivars Cigal and Excel. The effects of two types of fertilizers were compared: that of ammonium nitrate with that of the product Entec-26. On the basis of the results obtained, it was shown that endive cv. Excel produced a marketable yield that was on average by 35.5% higher than that of the cultivar Cigal. A significantly higher marketable yield of endive was obtained by fertilizing with a single dose of the fertilizer Entec-26, particularly at the rates of 90 and 135 kg N·ha^-1, and also 180 kg N·ha^-1. The experiments also revealed a significant effect of the fertilization method and nitrogen application rate on the biological value of the endive cultivars under evaluation. The cultivar Excel was characterized by a higher degree of nitrate accumulation, whereas the cultivar Cigal had a higher vitamin C content, dry weight, and chlorophyll content.