The effect of the mowing time of alfalfa on its feed productivity

The research was conducted at the SibNII Kormov hospital of the Siberian Branch of the Russian Academy of Sciences, located in the northern forest-steppe of the Ob region of the Novosibirsk region. The soil of the experimental site is zonal – leached chernozem, medium-sized, medium-humus, medium-loamy. The purpose of the research is to determine the timing of the second alfalfa mowing and to determine the periods during which the otava could be used in the raw material conveyor. The mowing ripeness of the first mowing of alfalfa during the years of use occurred 45–57 days after the start of regrowth (V = 11 %). Late mowing dates from alfalfa trees extended its growing season from 56 to 95 days. A strong relationship was found between the length of the interaxial period and the average daily air temperature (r = -0.97. 0.90), as well as the sum of temperatures and precipitation (r = 0.73–0.99). It was noted that in alfalfa, the sugar content in the roots decreases from early to late harvesting by 15% from 13.6 to 11.6 (V = 21 %), which increases the risk of its death in winter. Late mowing of alfalfa reduced the yield of dry weight by 13–21 % in total for two mowing. The decrease in the yield of the first mowing for the next year was 0.35–0.76 t/ha (7–15 %), the second – by 0.42–1.12 t/ha (14–36 %). When mowing otava in the early stages, the content of feed units was 0.74–0.77, OE 10.2–10.2 MJ, and digestible protein 161– 171 g/k units. At late harvest times, the content of feed units per 1 kg of feed decreases by 5 % in the first and 10 % in the second mowing, the yield of metabolic energy by 4 and 7 %, respectively, and the provision of digestible protein to the feed unit by 6 and 16 %.