Productivity of the facultative barley variety ‘Marusya’ depending on the use of mineral fertilizers and the growth retardant ‘Moddus’ in the southern part of the Rostov region

The current study was carried out in the southern part of the Rostov region at the FSBSI “Agricultural Research Center “Donskoy” in 2018–2020. The purpose of the study was to investigate the combined effect of mineral fertilizers and treatments with the growth retardant ‘Moddus’ on productivity of the barley variety ‘Marusya’. In the course of the study, there was identified high responsiveness of the facultative barley variety ‘Marusya’ to the use of mineral fertilizers. Without fertilization, the productivity was 3.46–3.59 t/ha, and 0.87–1.57 t/ha when using the fertilizers. The maximum productivity and protein percentage were established in the variants with the introduction of N79P82K57 according to the active ingredient, with 5.81 t/ha and 0.55 t/ha, respectively. The treatment of plants with the growth retardant ‘Moddus’ contributed to productivity increase on 0.13–0.22 t/ha on average over the years of study. Under the effect of the growth retardant ‘Moddus’, the number of productive heads increased on 5–19 pieces/m2 , there was also a tendency to an increase in the number of grains per head and grain weight per head. The growth retardant ‘Moddus’ contributed to a decrease in plant height on 3.6–5.6 cm, at the same time there was a tendency to increase length of head on 0.2–0.5 cm in comparison with the control variant. Mineral fertilizers effectively increased nature weight of the facultative barley variety ‘Marusya’. Without fertilization, nature weight of grain was 579 g/l and 584 g/l, and when using fertilizers, it increased on 16–27 g/l or 2.7–4.6%. Productivity increase in the variant when treating with the growth retardant ‘Moddus’ resulted in an increase of the indicator of conditional net income over the control variant on 745–1884 rubles/ha.