Effects of N application rate on yield and plant N uptake and utilization of Orychophragmus violaceus

Plot experiments were carried out to study the effects of nitrogen(N) application rate on fresh yield,nutrient contents and accumulations,seed yield and N use efficiency of Orychophragmus violaceus.Results showed that compared to no N application,the fresh yield,nutrient accumulations and seed yield were increased significantly after N application.With 135kg/hm2 N application rate,fresh yield,N,P,K accumulations and seed yield were optimal,reaching 21 350,67.17,11.62,87.05 and 993kg/hm2 respectively.With increased N application rate,N agronomic use efficiency(AUE),partial factor productivity(PFP) and apparent recovery efficiency(ARE) of O.violaceus decreased significantly.Excessive N had negative effects on growth of O.violaceus.