Soil environment has been greatly improved through transforming saline alkali land in Quzhou county, Hebei Province. Earthworms in this area are relatively abundant and there are 3 families, 6 genera and 6 species. Allolobophora trapezoides, Eisenia foetida of Lumbricidae and Drawida japonica of Moniligastridae are the dominant species. The average population density of earthworms is 16.53 /m 2, and the biomass is 4.81 g/m 2. This has reached normal level of farming ecosystem. It showed by the ag...