Application of nitrogen fertilizers to spring wheat on meadowchernozem soil in the Omsk Irtysh region

The effectiveness of fractional application of nitrogen fertilizers in cultivation of spring common wheat was studied in the conditions of the Omsk Irtysh region on meadow-chernozem medium-sized medium-humus heavy loamy soil. The research object was spring common wheat (Triticum aestivum L.) cv. ‘Melodiya’. The purpose of the research was to establish the effectiveness of fractional application of nitrogen fertilizers depending on the level of labile phosphorus in meadow-chernozem soil on yield and grain quality of spring common wheat in the conditions of the Omsk Irtysh region. The field experiment had three factors (2×4×2): Factor A — phosphorus background: 1. No fertilizers; 2. Application of P₃₀ a. i./ha; factor B — main application of ammonium nitrate in increasing doses: 0, N₃₀, N₄₅, N₆₀; factor C — foliar feeding with ammonium nitrate and carbamide at a dose of N₃₀: 1. Once in heading stage; 2. Twice in heading stage and milky ripeness. It was found that the most effective was main application of nitrogen-p hosphorus fertilizers in doses of N_30–45P₃₀; crop productivity in these variants increases by 40…48 % in comparison with the nonfertilized variants due to the gain in 1000-seed weight (r = 0.40…0.42), productive stooling (r = 0.83). The agronomic profitableness of one kg of a. i./ha applied fertilizers in these variants was 21.5 and 19.9 kg of grain with 7.5 and 6.1 kg increase in protein content, respectively. Late foliar sprayings, regardless of their number, did not increase crop productivity and quality of wheat grain. Thus, fractional application of nitrogen fertilizers in years with insufficient moisture levels (hydrothermal index 0.6–0.7) is not effective.