The effect of nitrogen fertilizers on yield and biological value of Chinese cabbage grown in spring season

摘要

The experiment was conducted between 1999-2000. The purpose of the research was to evaluate the effect of nitrogen fertilization on the yield and biological value of Chinese cabbage, Optico variety, grown in the spring season. There were compared objects with prevegetative fertilization in the amount of 50, 100, 150, 200 kg N~.ha~(-1) and divided fertilization in the amount of 100+50 and 100+50+50 kg N~.ha~(-1). Top-dressing was applied after 2 and 4 weeks from planting. It was found out that the application of the biggest dose 200 kg N~.ha~(-1) wholly before the vegetation gives the highest total yield (62.45 t~. ha~(-1)) and marketable yield (46.34 t~. ha~(-1)), however it spoils their health. It allows to achieve heads of the biggest unit weight(959 g). The greatest amount of nitrates and vitamin C were found in cabbage heads fertilized with 100 kg N~.ha~(_1) before the vegetation and 100 kg N~.ha~(-1) (50 + 50) as top-dressing.