The impact of seeding rate on weediness and yield of grass stands with Galega orientalis in the first years of use in the Leningrad region

The paper presents the results of research devoted to the problem of creating forage grass stands with the legume species - galega orientails on sod-carbonate soils in the Leningrad Region. Compared to other legumes, galega orientails has a long productivity, but in the first years of life it develops very slowly, due to which it is overgrown with weeds and does not provide quality raw materials for the production of grass fodder. Therefore, the main objective of the work is to study the possibility of creating a highly productive grass stand from the first years of use due to the optimal seeding rate and sowing method on the territory of the Leningrad Region. In studies conducted from 2021 to 2023, we compared two zoned varieties of the studied species - Krivich and Yalginsky. Taking into account the high ability of galega orientails tovegetative reproduction, not only 100% seeding rate - 26 kg/ha, but also underestimated rates were tested: 75%, or 19.5 kg/ha, and 50%, or 13 kg/ha. Seeds were sown both pure and in a mixture with timothy- grass (Leningradskaya 204). We found that galega orientails, being a long-lived species, grew extremely slowly in the first year after sowing, regardless of weather conditions, and this biological feature persisted even in the second year of life, which was particularly clearly manifested in the species composition of the created grass stands. The analysis of the botanical composition of the studied grass stands of the first year of use or the second year of life indicates their high weediness, especially of single species (76-93%). Mixed sowing of galega of Krivich or Yalginsky varieties with timothy-grass directly influenced the weediness in the studied grass stands, where the content of non-sown species was significantly lower. Only in the third year of life or the second year of use high quality grass stands with a high content of legume component are formed. Yield data also indicate a weak production process in the first year of use or in the second year of life - from 0.405 to 4.870 t/ha dry weight in both experiments. It is worth noting that a full yield of economic value can be obtained only in the third year of life or the second year of use, when, depending on the variant of the experiment, the productivity of the studied herbage varies from 2.2 to 8.9 tons of dry mass per hectare.