engleski

Nitrogen use efficiency in winter wheat

Nitrogen use efficiency of winter wheat grain, as valuable indicator for rational N fertilization supply, was investigated in a field experiment in middle continental Croatia under four mineral N fertilization treatments (0, 100, 200 and 300 kg N ha-1) during two growing periods (2002/03, 2005/06). Total N content in grain, yield, N uptake by grain, and soil N (N-NH4, N-NO3) status were examined as well to indicate relations between N trial treatments and growing years. Over total investigated period, above mentioned factors significantly differ per nitrogen levels and years. The highest total N content in winter wheat grain was recorded in N300PK treatment during 2002/03, but the highest yield was reached in growing period 2005/06 in treatment with 300 kg N ha-1. Growing period 2002/03 was signed as extremely hot and dry, which is the reason for lower yields, N content and NUE per fertilization treatment, compared to 2005/06. NUE values varied from 9.21 kg kg-1 in treatment with 300 kg N ha-1 (2002/03) up to 24.13 kg kg-1 in treatment with 100 kg N ha-1 (2005/06). During investigated growing years NUE was decreased with increasing nitrogen fertilization levels. The best use efficiency of applied nitrogen fertilization was at level of 100 kg N ha-1, which is consider as rational application regarding nitrogen emissions into environment.

nitrogen use efficiency; mineral N fertilizer rates; winter wheat; N content; soil available N status

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