Effects of Row Covers Using Non-woven Fleece on the Yields, Rate of Bolting, and Quality of Heading Chinese Cabbage in Early Spring Cultivation

The aim of the research was to determine the impact of row covers on the growth, yield, and selected nutritional compounds contents in Chinese cabbage (Brassica rapa L. Pekinensis Group), cultivated in a field with or without non-woven fleece (17 g·m -2 ). Application of row covers accelerated the growth and development of the plants due to more favorable microclimatic conditions than in an open field. All tested biometrical parameters of the rosettes, determined after removing covers, were considerably higher than in the uncovered control. Therefore, direct covers could be successfully used for promote the growth of Chinese cabbage rosettes after transplanting. Total and marketable yields of covered plants were higher by 36% and 91%, respectively, than in the control. No external flower stalks were observed in either treatment, but about 50% of control heads had internal bolters. Row covering could be an effective prevention method against Chinese cabbage bolting in spring production in Central Europe. Laboratory analysis performed directly after removing covers showed higher contents of L-ascorbic acid, chlorophylls, and carotenoids in the plants in an open field. However, in the subsequent few weeks, such differences between treatments decreased and at harvest time, the level of these compounds was similar. Mature heads of control Chinese cabbage contained significantly more soluble sugars, crude fiber and thiocyanates than covered plants. The models were proposed to predict changes in fresh and dry weight as a function of time.