Growing techniques of new forage crops under permafrost conditions (case study of the Republic of Sakha (Yakutia)

Abstract

In the permafrost floodplain soils of the Khangalasskiy District of the Republic of Sakha (Yakutia), the studies were conducted in from 2023 through 2025 to determine the effect of different sowing dates and humic products on the growth and development of non-conventional crops, millet and sweet sorghum in comparison with oats when grown for forage. The research goal was to reveal the specific features of forage productivity formation in millet and sweet sorghum depending on the growing techniques in the permafrost floodplain soils of the Khangalasskiy District of Yakutia. The research targets were common millet (Barnaulskoye 98 variety) and sweet sorghum (Galiya variety) in comparison with the Rovesnik oat variety. There were three sowing terms: the first ten-days of June (June 02, June 04, and June 06), the second ten-days of June (June 12, June 14, and June 16), and the third ten-days of June (June 22, June 24, and June 26). The crops were treated at the booting stage with the Lignogumat company products: Agrolan, Ligno Gumate, and Normat L. The accounting area of the experimental plots was 25 m² with four replications. The plot layout was randomized. The sowing technique was row sowing with 30 cm row spacing. It was found that the highest field germination was observed for forage crops sown in the third ten-days of June (91.4–94.9% of the laboratory germination rate). Under cryolithozone conditions, sweet sorghum Galiya developed slowly regardless the sowing terms with plants remaining at the booting stage in autumn; common millet Barnaulskoye 98 reached the flowering stage. The lowest weed infestation before harvesting the crops studied for forage was observed in the variants sown in the third ten-days of June, where the weed count decreased by 6-9 plants per m². The maximum leaf area was observed in the Barnaulskoye 98 common millet (138.0 cm² per plant with an index of 3.4) and the Galiya sweet sorghum (128.4 cm² per plant with an index of 3.2) when sown in the third ten-days of June with the application of the Ligno Gumat AM product.