Abstract:The study was conducted in Huantai County Shandong Province in North China to study the secondary succession of earthworm population under low and high soil fertility in agro-ecosystem. The result shows that seven species were found both in two agro-ecosystems, but the earthworm population density and composition are different, the average earthworm population in the high fertility soil is relatively abundance, the population density is 83.83 in./m~2. Among the seven earthworm species, Aporrectae trapezoids...