Analysis of the productivity of sown legume-grass stands depending on alfalfa content, biostimulant application and weather conditions

Intensive arable farming based on monoculture cropping leads to soil erosion, loss of biodiversity, and chemical contamination. One approach to mitigating these negative effects involves diversifying agroecosystems through the use of mixed cropping, particularly legumegrass mixtures. Such systems contribute to improved soil fertility, increased yields, and enhanced crop resilience to biotic and abiotic stresses. However, limited awareness of the composition and effectiveness of these mixtures hinders their widespread adoption in agricultural practice. This study aimed to investigate the development of alfalfa-grass mixtures depending on alfalfa content and to identify the most productive variants suitable for the Right-Bank Forest-Steppe zone of Ukraine, capable of delivering high and stable yields over extended periods. The research was conducted in the Forest-Steppe of Ukraine during 2021-2023 within permanent crop rotations at the experimental field of the Agronomic Research Station of the National University of Life and Environmental Sciences of Ukraine, located in Pshenychnе Village, Bila Tserkva District, Kyiv Region. Several variants of alfalfa-grass mixtures were tested, with alfalfa content ranging from 35% to 75% and with the application of biostimulants (biochar, humic extract). The experiment was conducted according to a multifactorial field trial design with four replications. The primary indicator for evaluation was the yield of the grass mixtures over a three-year period. The findings revealed that the most productive mixtures were those containing 65-75% alfalfa, achieving the highest yields in the range of 35-37.6%. The use of biostimulants contributed to increased productivity; however, excessive application of these substances could reduce yields. The highest yield was recorded in the second year of the experiment, which was attributed to increased plant viability and favourable weather conditions. The results confirmed that an optimal alfalfa-to-grass ratio within the mixture is a critical factor in achieving stable yields. The effectiveness of biostimulants was influenced by the composition of the mixture and the growing conditions. Cultivating alfalfa-grass mixtures with 65-75% alfalfa proved to be an effective strategy for enhancing forage yield and production stability. The application of biostimulants can further improve productivity, although their efficiency depends on specific environmental conditions. The findings can be used to optimise crop area structure and support the adoption of environmentally sustainable agricultural practices