Effect of different densities and mixed community structures on seed yield and quality of Vicia sativa in Vicia sativa-Avena sativa mixtures

This study investigated the effects of population density and community structure on seed production of Vicia sativa in a cool climate region. We analysed and compared the seed yield, seed quality, seed yield components, and other biological characteristics of different sowing rates, sowing ratios, and patterns (mixed cropping and intercropping with Avena sativa). Results show that seed yield increased with increasing sowing rates. The seed yields of mixed cropping and intercropping were less than that of monoculture, but seed quality (germination potential) was better. Seed yield and quality increased with increasing V. sativa sowing ratios. The mixed patterns affected seed yield and quality. Population density and community structure influenced shoots per plant (Sh/P), pods per plant (Po/P), and, in some cases, pod length, seeds per pod, and germination rate. In the mixed cropping and intercropping systems, A. sativa was a stronger competitor than V. sativa. To increase V. sativa seed yield and seed quality, the competition ratio of V. sativa in mixed communities needs to be improved by increasing the mixed ratios of V. sativa and using an intercropping pattern. In conclusion, V. sativa seed fields need higher sowing quantities (equal or more than 120 kg·ha^–1), 75% V. sativa seeding rate + intercropping pattern, and higher mixed ratios in cool climate pastoral areas.