关键词: 栎空腔瘿蜂, 栎空腔瘿蜂, 种群生命表, 重要因子分析

Abstract: In view of the serious postharvest loss of leaf vegetables, the key nodes’loss rate of different supply chains of four kinds of leaf vegetables (lettuce, celery, rape, spinach) in Beijing was studied. Through a field survey of 23 large enterprises and cooperatives and vegetable production bases in 8 districts and counties of Beijing, the authors identified four major supply chain models in Beijing at present, including agriculture super-docking model, processing mode, individual-free market model, supermarket own-brand model, and studied the key nodes’loss rate. The results showed that: the average loss rate of the agriculture superdocking model was the highest, which could be up to 36.05%. The second was the supermarket own-brand model, its average loss rate was 32.64%. The average loss rate of the individual-free market model was the lowest, which was only 24.70%. Lettuce had the highest average loss rate in four major supply chain models, which could be up to 45.81%. The second was spinach, the rate could be up to 39.95%. Rape had the lowest average loss rate, which was only 16.58%. In addition, the acceptance standard of leaf vegetable was set, and the loss rate calculation formula was established. The differences of loss rate among the four main supply chain models and four kinds of leaf vegetables were compared. The study has certain significance on reducing postharvest loss rate of leaf vegetables and meeting the consumers’requirement for fresh vegetable.