The formation of the productivity of winter wheat depending on the level of the contamination of crops under the conditions of the application of resource-saving technology in the conditions of Southern Ukraine

Abstract

The aim of the study was to determine the effect of different levels of weed infestation on the morphological and physiological characteristics and structural elements of the yield of the winter wheat Duma Odeska variety in the conditions of the Southern Steppe of Ukraine. Results and Conclusions. A data analysis showed that the winter wheat Duma Odeska variety formed seedlings even with a lack of soil moisture (moisture at a depth of 10 cm – 13.5 %) and demonstrated intensive development of leaf mass up to 33 ÷ 35 g/m² in the shoot phase. In the tillering phase, the average number of productive stems was 3 ÷ 5 pcs./plant, and the tillering coefficient was 3.2, which contributed to early row closure and partial weed suppression. At a medium level of contamination (150 ÷ 200 plants/m²), the main productivity indicators decreased moderately: the number of productive stems was 518 pcs./m², the number of grains per year was 32.2, the mass of 1,000 grains was 41.1 g, and yield was 4.75 t/ha. With high contamination (more than 250 plants/m²), the number of productive stems decreased to 446 pcs./m², the number of grains per ear to 29.4, the mass of 1,000 grains to 38.7 g, and yield to 3.92 t/ha. The following types of weeds caused the greatest damage: common millet, wild oats, creeping mustard, common poppy, nettle and fescue. These species dominated the three waves of weed germination during the growing season. The variety showed relative drought and heat tolerance, including the preservation of the assimilation surface under temperature stress up to +35 ÷ +36 °C in the earing phase and root penetration to 120 ÷ 140 cm. However, the positive characteristics of the variety did not fully compensate for weed pressure above 200 plants/m², especially under the conditions of a moisture deficit. The practical importance of the study lies in identifying weed-density thresholds that can guide control measures in the Southern Steppe of Ukraine.