Oana Mîrzan

This paper aimed to study combinations of some monoecious hemp varieties created at A.R.D.S. Secuieni and evaluate the combined influence of the variety of hemp used, the distance between rows of hemp, and the application of the Secuieni method on seed production. The Secuieni method is a cultivation method for hemp seed that is suitable for mechanical harvesting with grain combined directly from fields. This method consists of reducing the height of plants below 2 m, increasing the field uniformity, increasing seed production (sometimes by over 50%), and reducing the seeding rate from 10–15 kg/ha to 4–5 kg/ha. An experiment was carried out within the Agricultural Research—Development Station Secuieni in an experimental field in the monoecious hemp breeding laboratory. The results obtained during 2019–2023 showed that the influence of the variety led to production increases of 276 Mg·ha⁻¹, which were obtained by the Secuieni Jubileu variety compared to the control variety, Succesiv, which had a yield of 1808 Mg·ha⁻¹. The distance between the rows generated seed yields with values between 1908 Mg·ha⁻¹ and 1967 Mg·ha⁻¹, with statistically insignificant differences. The use of the Secuieni method led to production increases with different degrees of significance compared to the control variant. When analyzing the influence of the interaction between the genotype and the distance between the rows, it was observed that the productions obtained varied between 1767 Mg·ha⁻¹ (Succesiv × 50 cm) and 2121 Mg·ha⁻¹ (Secuieni Jubileu × 70 cm). In the analyzed period, the yields oscillated between 1460 Mg·ha⁻¹ (Zenit × uncut) and 2437 Mg·ha⁻¹ (Secuieni × two cuttings). In the case of the interaction between the distances used and the cuttings applied, the obtained production values varied between 1458 Mg·ha⁻¹ (50 cm × UC) and 2402 Mg·ha⁻¹ (70 cm × c₂). At the same time, in the case of the combined influence of the three experimental factors, the application of two cuttings, regardless of the variety and distance used, led to statistically assured production increases compared to the control variant (Succesiv × 50 CM × UC).

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 - Neamţ, 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.