Effect of topdressing with nitrogen on the yield and quality of winter wheat grain

Small-plot field experiments were established in the first decade of October at the Plant Breeding Station of Sládkovičovo-Nový dvor with winter wheat (Triticum aestivum L.), variety Astella. There was investigated an effect of topdressing with nitrogen on the yield of winter wheat grain and its quality characteristics in the experiment. Nitrogenous fertilizers were applied at the growth phase of the 6th leaf (Zadoks = 29). Soil of the experimental stand was analysed for inorganic nitrogen content (Nan) down to the depth of 0.6 m of soil profile. Productive nitrogen fertilizing rate was computed to ensure Nan content in soil on the level of 120 and140 kg N/ha, respectively. Three various forms of fertilizers were examined, urea solution, ammonium nitrate with dolomite, and DAM-390. Different weather conditions statistically highly, significantly influenced grain yield in respective experimental years. Topdressing with nitrogen caused a statistically highly significant increase of grain yield in all fertilized variants ranging from +0.35 to +0.82 t/ha according to respective treatments. Average grain yield in unfertilised control variant represented 7.23 t/ha. Nitrogen nutrition showed a positive effect on the main macroelements offtake (N, P, K, Ca, Mg, S) by winter wheat grain in all fertilized variants. Nitrogen fertilizing to the level of 140 kg/ha N in soil positively influenced formation of wet gluten and crude protein with highest increment in variant 5 (solution of urea) representing +12.8 and +10.7%, respectively in comparison to control unfertilised variant as well as to variant 2 (solution of urea and fertilizing on the level of120 kg N/ha) where increments represented +8.8 and 9.7%, respectively. Thousand-kernel weight, volume weight and portion of the first class grain were not markedly influenced by nitrogen fertilizing.