THE TYUMEN REGION WEATHER CONDITIONS IMPACT ON THE DRY MATTER CONTENT IN THE RED CLOVER GREEN MASS

The purpose of research is to study the influence of weather conditions in the Tyumen Region on the percentage of dry matter in the green mass of late-ripening varieties of red clover during the harvesting period. Observations were carried out on the experimental field of the Research Institute of Agriculture of the Northern Trans-Urals – a branch of the Tyumen Scientific Center of the Siberian Branch of the Russian Academy of Sciences in 2015–2022 on plants of 12 late-ripening (single-cut) samples of red clover of the 1st year of use. Weather conditions in most years were warm with sufficient precipitation, dry conditions were observed only in 2021; the hydrothermal coefficient (HTC) of Selyaninov was 0.47–2.55. The date of resumption of vegetation was noted in the second decade of April, the cutting of green mass was carried out in the second decade of July. In 2015–2022 harvesting of green mass from varieties of red clover ranged from 17.9 to 62.5 t/ha, with a dry matter content in it from 20.4 to 37.1 % and a difference between the values by years from 0.8 to 13.3 %. There was a relationship between the value of the HTC and the ratio of fodder products in freshly harvested (green mass) and dry form (hay). With HTC values >2, the collection of green mass was 4.2–4.6 times higher than the yield of hay with HTC < 2, 3.0–3.4 times. The dry matter content of green mass under conditions of excessive moisture (HTC = 2.4–2.55) decreesed – 21.9–23.5 %, with a lack of moisture (HTC = 0.47–1.25) increased – 31.2–34.7 %, which was confirmed by a significant negative correlation (r = -0.753–0.965) between the dry matter content and the HTC for the season (April – July) for all varieties. The sum of active temperatures in April-May (r = 0.746–0.846 for 5 varieties) could also contribute to the increase in the dry matter content in the green mass, which indicated the importance of warmth during the spring regrowth.