ALFALFA VARIETIES PRODUCTIVITY IN SAKHALIN ISLAND CONDITIONS

The objective of the study is to evaluate the productivity and nutritional value of various alfalfa varieties in their second to fifth years of growth under the conditions of Sakhalin Island. Research was conducted at the Sakhalin Research Institute of Agriculture, a branch of the All-Russian Institute of Plant Protection, in a field trial conducted on meadow-sod-gley soil from 2021 to 2025. Ten varieties were presented, with the Demetra alfalfa variety, included in the State Register of the Russian Federation for the Far East, selected as a control. The most pronounced differences in height between the alfalfa varieties became apparent in their third year of growth. The Taisiya, Agnia VIK, and Nakhodka alfalfa varieties had the highest average cutting height, exceeding the standard by 3.4–6.1 %, while the Nakhodka, Uralochka, Pavlovskaya 7, and Demetra varieties had the greatest foliage. The average plant height from the first to the second cutting decreased by 16.1 %, while foliage increased by 31.7 %. In the conditions of southern Sakhalin Island, alfalfa is capable of sufficiently exploiting its genetic potential and, with two cuttings, forming highly productive stands with a dry matter yield of 14–24 t/ha. The maximum biomass was accumulated by second-year alfalfa varieties. Over four years of using alfalfa stands, it was noted that, on average, 64 % of the total dry matter yield was achieved in the first cutting (13.2 t/ha in the first cutting versus 7.5 t/ha in the second). The differences between the standard variety and the alfalfa varieties in their second to fifth years of life that exceeded it in dry matter yield ranged from 6 to 21 %. The top three varieties were Sarga, Taisiya, and Nakhodka, surpassing Demetra by 15 to 21 %. The variation in feed unit yield per hectare ranged from 11.3 to 19.9 %, with Sarga, Taisiya, and Nakhodka leading the way in this indicator, exceeding the standard by 6 to 24 %. These same three varieties also provided the highest feed unit yield per hectare (11 to 33 % higher than the standard).