Abstract
The article presents the results of a study on the effects of component composition and growth stimulants on the yield and nutritive value of perennial grasses and grass mixtures under the conditions of Northern Kazakhstan. The research was conducted in 2023–2025 using pure stands of alfalfa and smooth brome, mixtures of alfalfa and smooth brome, and three-component mixtures of alfalfa, smooth brome, and sainfoin. Black Jak, Miller Start, AminoMax, and Lider-S were applied. Green mass yield, dry matter yield, and the content of crude and digestible protein, fiber, metabolizable energy, and feed units were determined. Among the grass mixtures, the highest yield was obtained from the mixture containing 40% alfalfa and 60% smooth brome treated with Miller Start: green mass yield reached 17.88 t/ha, while dry matter yield was 5.39 t/ha. The most balanced nutritive value was observed in the mixture containing 50% alfalfa, 30% smooth brome, and 20% sainfoin. When Miller Start was applied, the crude protein content in this treatment was 12.97% in 2024 and 13.09% in 2025. Correlation analysis confirmed the relationships among yield, dry matter yield, and the main indicators of forage nutritive value. The research results support the combined selection of component composition and growth stimulant according to the required productivity and nutritive value of the sward.