Productivity and Vegetation Structure Evolution of Complex Mixtures of Perennial Forage Grasses and Leguminous Species, in the Conditions of the Center of Moldova, Romania

Research in our country on the number of species needed to set up temporary grasslands has highlighted the productive and structural superiority of complex mixtures of more than two species. Although for the composition of mixtures is intended to use species and varieties as well as possible adapted to the environment, annual climatic variations sometimes influence the behaviour of the species and therefore productivity. The need to reduce doses of chemical fertilizers in the exploitation of temporary grasslands requires finding solutions to saturate the multiple ecological niches of temporary grassland ecosystems. These can be achieved by using a mix of a larger number of species adapted to the pedo-climatic conditions specific to the cultivation area, as well as by using an appropriate ratio between these species. The purpose of the study was to follow the productivity and evolution of the vegetation structure in some crop mixtures, in different conditions of fertilization. The research was conducted under the conditions of the Center of Moldova from Romania at ARDS Secuieni - Neamt, during the 2018-2021 period,. The production of dry matter according to the type of mixture and the doses of fertilizers used the percentage of participation of perennial grasses and leguminous species in the vegetation structure, as well as its quality was analysed. From the analysis of the obtained data, the highest feed production (24.82 Mg.ha(-1) DM) was obtained in the variant fertilized with N80P40 and sown with the mixture consisting of 70% grasses (Festuca arundinacea 30% + Dactylis glomerata 20% + Festuca pratensis 20%) and 30% leguminous (Medicago sativa 20% + Trifolium pratense 10%). At the first cut, in the mixture of 70% grasses (Festuca arundinacea 30% + Dactylis glomerata 20% + Festuca pratensis 20%) and 30% leguminous (Medicago sativa 20% + Trifolium pratense 10%), the participation percentage of grasses in the vegetation structure varied from 57% in the non-fertilized variant, to 61% in the variant fertilized with N80+40P40. The quality of the feed obtained was good for all variants studied.