The influence of the phase of the growing season on the mineral composition of the narrow-leaved fireweed

In the experiments the mineral composition of narrow-leaved fireweed was studied in different phases of its growing season in the conditions of the North- Western region of Russia in the Vologda region. It was experimentally established that narrow-leaved fireweed is a promising forage plant in the North-Western zone of Russia. It can meet the needs of lactating cows in macro-and microelements, except sodium, zinc, copper and cobalt. Taking into account the fact that there is a lack of phosphorus in the plant feeds of the Vologda region, using narrow-leaved fireweed for feed will to some extent compensate for its lack in the dairy cattle diet. The dynamics of the mineral content in the plants of narrow-leaved fireweed in dry matter is: the growth of the stem – macroelements; calcium – 7.53 g/kg, phosphorus – 7.36, magnesium –3.42, sodium – 0.17, potassium – 20.8 g/kg. Microelements: zinc – 47.5 mg/kg, copper – 5.39, cobalt – 0.25, iron – 129 mg/kg of dry matter of the plant. It is established that the chemical composition of fireweed changes in the process of development and growth. Therefore, when feeding the green mass to cattle, as well as when harvesting raw materials from it for the production of various feeds (hay, haylage, silage, grass meal), it is necessary to take into account the optimal content of macro- and microelements in its plants, which will allow to better balance the rations of cattle in mineral nutrition and get higher productivity from animals.