Effect of Lupin Extract and Nitrogen Fertilization on Yield Quality of Celeriac

The results of a study on possibilities of utilization of lupin extract are presented. The extract was a waste material from the de-bittering process of bitter lupin seeds and might affect yield and chemical composition of celeriac. Type of nitrogen fertilizer (pure ammonium nitrate or its form supplemented with molybdenum and magnesium) was another factor tested. The study, based on field experiments, was conducted in the years 1999-2001. It was found that fertilization with ammonium nitrate, and especially with its form enriched in magnesium and molybdenum, was a factor significantly affecting yield of celeriac. After use of lupin seed extract slight increase in yield and total nitrogen content as well as evident reduction in nitrates content in celeriac were observed. Average decrease in content of this nitrogen form in roots and leaves was 14.8% and 29.6%, respectively, as compared to control. Tested factors did not influence significantly potassium and sodium contents in leaves and roots of celeriac.