The features of autumn terms of meadow grass mowing in the conditions of the middle taiga subzone of Yakutia

The study was the first to present the data on reserve substances in the roots of haymaking grass mixtures for double-crop use under conditions of the first group agroecological lands of the Near-Lena agricultural landscape. The object of the study was seeded grass stands of recognized in the Republic varieties of perennial grasses: Elymus mutabilis Lensky and Elymus sibiricus Kamalinsky-7. It was proved by the studies that the content of water-soluble carbohydrates in the roots of seeded grasses in the autumn period increased by 2.8-3.1 times in average as compared to spring. The stands of Elymus mutabilis of Lensky variety mowed within average dates (September, 1-5) at average soil temperature 11.5-12.5 °C at the depth of 0-20 cm, showed the increase of soluble carbohydrates content from 3.6 % in spring to 11.2 % in autumn. Mowing Elymus mutabilis stands on August, 20-25 at average soil temperature from 13.2 to 17 °C provides feed content of 0.65-0.66 and 0.65-0, 67 at a late date (September, 10-15). Besides, the content of digestible protein in 1 feed unit varied from 85 to 92 g. The grass mixture consisting of both Elymus mutabilis and Elymus sibiricus maintained good productivity within the average mowing dates of September, 1-5 at average soil temperature 11.5 to 12.5° C with forage content units to 0.64 and digestible protein in 1 feed units up to 93 g of raw protein. The obtained data testify of possible mowing of the grass mixture before September, 1-5 without any harm to feed quality, taking into account the accumulation of reserve substances in the autumn period.