The effect of biodegradable nonwoven direct covers on yield and quality of winter leek

During this two-year experiment (2008-2010), the ‘Kenton’ leek cultivar was grown in the field from July to March/April of the following year. During the winter months the plants were kept under biodegradable nonwoven covers (Bionolle - polybutylene succinate, 59 and 100 g m^-2). The control treatments were left uncovered. Some cracks and tears in the biodegradable nonwoven covers were observed. The covers resulted in better leek yields. In the first season the bleached parts of the leek contained more ascorbic acid when kept under the Bionolle 100 g m^-2 cover. The lighter nonwoven (59 g m^-2) cover caused a grater accumulation of soluble sugars. Biodegradable films, used in the winter cultivation of leek, increased the soil temperature by 1°C on average.