Stable growth of high-quality grain production is one of the main tasks facing the agro-industrial complex of Ukraine. The leading grain crop is winter wheat. Diseases, especially root rots, which are dominant in the harmfulness of wheat diseases, are a limiting factor in the growth of grain production. Crop failure due to this disease can range from 5 to 50% or more.
Goal. Evaluation of root rot damage of winter wheat crops after application of different doses of fertilizers.
Methods. Laboratory, mathematical, statistical.
Research results. As a result of the conducted research, it was established that the highest intensity of damage to plants by root rot is observed in the phase of milk ripeness, which is 11–11.5 % against 1.2–1.4 % in the phases of tillering and earing. However, the spread of the disease is high from the beginning of the tillering phase and is 100 %. Application of nitrogen fertilizers does not affect the intensity of development and resistance of winter wheat against root rot. The development of root rot does not affect the number of productive stems. Yes, their number is 540–579 pcs/m2 depending on the dose of fertilizers. However, the development of root rot greatly reduces the productivity of the ear. Thus, the mass of grains of one ear decreases to 0.67–0.68 g against 1.48–1.75 g, and the mass of 1000 grains down to 20–21 g against 37–45 g.
The Tronka winter wheat variety is characterized by low resistance to lodging, which in 2011 decreased from 7 points to 1 point in the variant with the highest dose of nitrogen fertilizers (150 kg/ha per year), which caused a decrease in the weight of one ear of grain to 1. 48 vs. 1.75 g in the version without fertilizers, weight of 1000 grains up to 37 g vs. 45 g. The highest grain yield of winter wheat was obtained in the variant with a one-time application of nitrogen fertilizers in the spring at a dose of 50 kg/ha d.r. against 6.80 t/ha in the N150P100K100 variant. The yield of grain in foci of root rot development ranges from 2.51 to 2.58 t/ha. The development of root rots also reduces grain quality indicators. For example, the protein content decreases to 8.1–8.5 % against 12.5–14.3 % against the background of less development of the disease, and the gluten content accordingly decreases to 15–15.6% against 25.2–34.4 %.
Conclusions. In the conditions of the Right Bank Forest-Steppe of Ukraine, on podzolized chernozem, in order to obtain a sustainable winter wheat crop, nitrogen fertilizers must be applied in a dose of N50 in top dressing on a background of P50K50: it ensures the least loss of grain from root rot.