NELI VALEVA; YONKO STAMENOV
University of Forestry, Faculty of Agronomy, BG-1756 Sofi a, Bulgaria
Valeva, N. and Y. Stamenov, 2017. Nitrogen removal assessment in omitted plot trials with wheat and barley. Bulg. J. Agric. Sci., 23 (3): 449–452
Nutrients removal by crops is one of the key indicators to determine the optimal nutrient status. During the period 2009– 2012 in the region of Pomorie and village Sadievo (municipality Nova Zagora), a Eutric Vertisol and Chromic Luvisols, it was assessed the infl uence of the nutrition conditions on the nitrogen removal by winter wheat (variety „Aglika”) and winter barley (variety „Aheloy“). Eight nutrition treatments were studied during the field experiment, including addition and omission of nutrients – untreated control; N; P; K; NP; NK; PK and NPК. Yield parameters and chemical composition of the main and secondary production were reported every season to determine the effi ciency indicators and nitrogen removal per harvested area and per yield unit (grain). Analysis of the data for both sites of the research, shows that alone phosphorus addition and potassium addition, as well as nitrogen omission (PK) led to lower nitrogen removal per ton of wheat production compared to conditions with balanced nutrition (NPK).The highest nitrogen removal per ton of barley production was reported under conditions of single addition of nitrogen for the region of Pomorie, and the village Sadievo. Nitrogen removal for one tone production of wheat and barley was variable depending on the specifi c conditions of the experimental regions and nutrition conditions. The differences were relatively small and in average nitrogen removal for one tone production wheat was higher in the region of Pomorie – 24.4 kg t-1 compare to 22.5 kg t-1 in the region of Sadievo. For barley, nitrogen removal was higher in Sadievo – 22.2 kg t-1 compare to 21.6 kg t-1 for the region of Pomorie. For both crops at the two regions of the study, the highest nitrogen removal for one tone production was reported under conditions of single addition of the nitrogen. The similar results for nitrogen removal for one tone of wheat and barley grain obtained under optimal nutrient conditions NPK showed the possibility of using universal data for the nitrogen removal in different regions.