Effect of seeding rate on growth and nutrient accumulation of Chinese milk vetch

A field trial was conducted to study the effect of seeding rate on the growth, fresh yield and nutrient accumulation of Chinese milk vetch (Astragalus sinicus L.). The trial included 7 seeding rate treatments ranging from 7.5 to 52.5 kg·hm^-2. The results showed that the number of emerged seedling increased with increasing seeding rate. However, number of branch and compound leaf, weight for per plant decreased with increasing seeding rate. Fresh yield also increased with increasing seeding rate. Significant differences were noted in fresh yield under seeding rate of 7.5~30.0 kg·hm^-2. Once seeding rate above 30.0 kg·hm^-2, however, no significant difference existed among the treatments. Seed yield initially increased with increasing seeding rate up to 15.0 kg·hm^-2, and then decreased with increasing seeding rate. Seeding rate had no significant influence on nutrient content, but greatly influenced nutrient accumulation. The accumulation of C, N, P, K, Ca, Mg, Fe, Mn, Cu and Zn significantly increased with increasing seeding rate. It was therefore concluded that the most suitable seeding rate was 30.0 kg·hm^-2 for green manure turnover, and 15.0 kg·hm^-2 for seed production.