EFFECT OF NITROGEN FERTILIZATION IN TRITICALE (X TRITICOSECALE WITTM.), CULTIVATED AFTER DIFFERENT PREDECESSORS. NITROGEN UPTAKE AND EFFICIENCY

The study is conducted at the experimental base of Department of Plant productionat Trakia University, Stara Zagora. Triticale is grown after five predecessors anddifferent nitrogen fertilization rates. The predecessors are wintering peas, springpeas, sunflower, common wheat and triticale. Nitrogen fertilization rates are 0 (N0),40 (N40), 80 (N80), 120 (N120) kg ha-1 after legumes and 0 (N0), 60 (N60), 120 (N120),180 (N180) kg ha-1 after the other predecessors. The influence of the predecessorsand nitrogen fertilization on the nitrogen uptake, assimilated nitrogen fromfertilization, nitrogen utilization and nitrogen required for 100 kg produce oftriticale is established. Nitrogen assimilation from fertilization increases with theincrease of the nitrogen fertilizer rates. With the obtained yield from triticale anaverage of 96.53 kg ha-1 N is extracted from the soil with the grain, 18.97 kg ha-1 Nwith the straw or a total of 115.50 kg ha-1 N. When growing triticale afterleguminous predecessors the utilization of nitrogen is 35.39% and afterpredecessors sunflower, wheat and triticale - 28.76%. Nitrogen required for 100 kgyield of grain of triticale is 1.9 kg of nitrogen when growing after legumepredecessors and 2.8 kg of nitrogen after the other predecessors