The aims of the study were to determine the impact of various forms of nitrogen on the content and uptake of cooper, iron, manganese and zinc by sweet sorghum and to check what remains in the bagasse after extracting the plant juice. In 201-2011, field experiments were conducted on sweet sorghum (cv. Sucrosorgo 304) fertilized with different forms of nitrogen (nitrate, ammonium and urea). The fertilizer containing ammonia nitrogen markedly increased the amount of Mn in both years of the study and raised the amount of Zn in 2010. On average, significantly more Fe was found after fertilizing with nitrates (calcium nitrate), and more Zn was found after fertilizing with the form of ammonium (ammonium chloride). In 2010, there were significantly higher increments in the content of all the microelements. A lower content of microelements was found in the bagasse than in the whole plants. On average, throughout the whole study, a significant impact of the fertilization variants on the Zn content appeared. The highest uptake of Cu was found in plants which had been fertilized with nitrate and ammonium forms of nitrogen (ammonium nitrate), whereas Mn and Zn increased when fertilization included ammonium in the form of ammonium sulphate. After fertilizing with ammonium chloride, the uptake was slightly lower. On average for 2010-2011, the highest level of Cu, Mn and Zn occurred in the bagasse from plants that had been fertilized with ammonium chloride.

19.2.2014