Study on Nitrogen Deficiency and Compensatory Effect of Early Maturing Rapeseed at Different Growth and Development Stages
In order to investigate the effects of nitrogen deficiency and compensation in early maturing rapeseed at different growth stages,yield and its components,dry matter accumulation,and nitrogen absorption and utilization efficiency were investigated with Ganyou 105 as material under the treatment of nitrogen deficiency at the stages of seedling stage,overwintering stage,bolting stage,initial flowering stage and final flowering stage then equal and double quantity nitrogen recovery application at the later growth stage by means of pot experiments.The results showed that nitrogen deficiency from overwintering stage to bolting stage had a significant effect on dry matter mass,and the total dry matter mass increased by 7.71%with double quantity nitrogen recovery application compared with equal quantity nitrogen application.Nitrogen deficiency before overwintering stage and after first flowering stage had little effect on yield per plant of rapeseed.Plant height and effective branch number of rapeseed were significantly reduced under nitrogen deficiency at overwintering stage,and nitrogen deficiency at bolting stage had the greatest effect on effective pod number per plant.There were some compensation effects on seed weight per plant,effective pod number per plant,seed number per pod,effective branch number and dry matter mass,but there were some differences in compensation effect and validity compensation period of each index.Nitrogen application sufficiently from overwintering stage to bolting stage would optimize nitrogen absorption and utilization efficiency.In general,the nitrogen demand and nitrogen deficiency sensitive critical period in early maturing rapeseed were from overwintering stage to bolting stage,and the effective nitrogen compensation critical period in early maturing rapeseed was initial flowering stage.
Early maturing rapeseedNitrogen deficiencyYieldNitrogen fertilizer utilizationCompensatory effect