Effects of sowing rate and row spacing on the seed yield and yield component traits of Onobrychis viciaefolia ‘Gansu’

The effects of different seeding rates (7.5, 15, 22.5, and 30 kg·ha⁻¹) and row spacing (30, 60, 90, and 120 cm) on the seed yield and yield of component factors of Onobrychis viciaefolia ‘Gansu’ were studied from 2020 to 2021 to provide technical guidance for the industrialization development of O. viciaefolia ‘Gansu’ in Tongwei County, Gansu Province. The results showed that row spacing was the main factor affecting seed yield. The seed yield was significantly higher at 60 cm and 90 cm than at 30 cm and 120 cm (P < 0.05); however, the sowing amount had no significant effect on the seed yield. Due to the interaction, the seed yield varied between 528.27 kg·ha⁻¹ and 1 423.81 kg·ha⁻¹. Among them, the seed yield was the highest at 60 cm and 22.5 kg·ha⁻¹, reaching 1 423.81 kg·ha⁻¹. Simultaneously, row spacing significantly affected the shoot numbers, effective shoot numbers, pod weight per inflorescence, and 1 000 seed weight (P < 0.05). Seeding rates also significantly affected the shoot numbers, effective shoot numbers, pod weight per inflorescence, pod weight per plant, and 1 000 seed weight (P < 0.05). The multiple analysis results of seed yield and its factors showed that pod numbers per inflorescence, full pod numbers per inflorescence, vintage rate, empty pod numbers per inflorescence, pod weight per plant, shoot numbers, and 1 000 seed weight were the main factors of seed yield. In summary, in the production of O. viciaefolia ‘Gansu’, the best combination is a 60 cm row spacing + a sowing amount of 22.5 kg·ha⁻¹. The O. viciaefolia ‘Gansu’ seed yield can be improved by reducing the empty pod numbers per inflorescence, decreasing the vintage rate, and increasing the pod number per inflorescence, shoot numbers, pod weight per plant, and 1 000 seed weight; however, attention should be paid to coordinating the relationship between various factors.