Effect of ultrafine manganese, zinc, and copper particles on the germination energy, germination capacity, and field viability of spring barley and common millet seeds

The study aimed to evaluate the effect of pre-sowing seed treatment with ultrafine particles (UFPs) of manganese, zinc, and copper on germination energy, laboratory and field germination rates, and plant survival at harvest. The subjects of the study were spring barley (cv. Lekar 2) and common millet (cv. Orenburgskoye 27). The UFP pre-sowing treatment variants were Zn 10-3 %, Mn 10-4 %, and Cu 10-6 %, with an untreated group serving as the control. The work was conducted from 2023 to 2025 in the Orenburg region. The use of Cu UFPs resulted in the greatest increase in germination energy observed in the experiment: 6.2 % for spring barley and 10.3 % for millet compared to the control. Laboratory germination rates for spring barley peaked with Mn and Cu UFP treatments (98.3 % and 98.0 %, respectively), while for millet, the highest rate was observed with the Cu UFP treatment (98.7 %). Field germination showed a marked dependence on hydrothermal conditions. In the drought year of 2023, field germination increased by 5.0 % for spring barley (Cu UFP variant) and 12.0 % for millet (Zn UFP variant) compared to the control. In the excessively wet year of 2024 and the favourable year of 2025, Cu UFP seed treatment increased field germination for spring barley by 4.0 % and 9.0 %, respectively, and for millet by 5.0 % and 2.0 %, relative to the control. The use of Cu-containing organo-mineral fertilizer increased barley plant survival at harvest by 11.0 % compared to the control under the favourable conditions of 2025. However, under the conditions of excessive moisture in 2024, a decrease in plant survival of 8.0 % for millet and 2.0 % for barley relative to the control was observed for this treatment.