LAUSR

A pot trial was aimed to investigate the effect of different forms of nitrogen fertilizer on the aboveground phytomass yield, vitamin C content and uptake of some macroelements by Brassica pekinensis. The trial was conducted in 2000 and 2001 in pots containing 10 kg of loamy brown soil. Optimized NPK nutrition with the rate of 90.9 kg/ha N increased phytomass yields of Chinese cabbage in all treatments compared to the unfertilized control. The most marked increase (by 55.6%) of yield was obtai- ned when N was applied in the form of (NH4)2 SO4. The yields in the other treatments declined as follows: NH4NO3 > Mg (NO3)2 > KNO3 > DAM-390. Positive effects of full NPK nutrition on vitamin C content were determined. Depending on the forms of N fertilizer, the content of vitamin C in fresh mass of cabbage decreased in the following order: DAM-390 (629.0 mg/kg of fresh mass) >Mg(NO3)2 > KNO3 > NH4NO3 > (NH4)2SO4. Optimization of NPK rates contributed to the increase in N, P, K, Ca, Mg and S uptake by the yield of final product in comparison with unfertilized control. The highest uptake of nutrients was determined in the treatment with N applied in the form of (NH4)2SO4.