Impact of soil fertility maintaining practice on earthworm population in high production agro-ecosystem in North China
不同土壤培肥措施对华北高产农田生态系统蚯蚓种群的影响

The study was conducted in high production agro-ecosystem in Huantai County Shandong Province of China North plain to study the impact of organic input and chemical fertilizer application on earthworm population. The result shows that there were seven species in Huantai high production agro-ecosystem, Among the seven earthworm species, Aporrectae trapezoids is the dominant species. The average earthworm population is 83.83 indiv./m~2. The highest population density was found in August 1998 among the five surveys of the study, the seasonal variation of the earthworm population is: summer>spring>autumn and winter. The impact of chemical fertilizer on the earthworm population depends on the organic input and the earthworm population density increases accordingly. The earthworm density of the treatments has the following ascending trend: Chemical fertilizer