An Ecological study on earthworm in farmland of salinity transforming area in north China plain
华北盐渍化改造区农田蚯蚓生态学研究——以河北省曲周县为例

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 age structure that the population structure of local earthworms is in a stable situation. The number of earthworms during the year is in the order of summer>early spring>autum.