Population Density and Biomass of the Terrestrial Earthworm in the Grasslands of three Different Soil Types Near Sapporo

Abstract

Observations of the earthworm population in the grasslands of alluvial, volcanic ash, and peat soils representing each feature were made in Sapporo, from the beginning of May to the beginning of November in 1966. Seven species in all were found in these grasslands: Allolobophora japonica, A. caliginosa, Dendrobaena octaedra, Pheretima hupeiensis, P. hilgendorfi, P. agrestis and P. sp. In the alluvial soil, six species were found, A. japonica being dominant and P. sp. subdominant. In the volcanic ash soil, five species appeared, A. japonica being dominant and D. octaedra subdominant. In the peat soil, D. octaedra was the only species obtained. A. japonica was common in the alluvial and volcanic ash soil, and D. octaedra was common in the volcanic ash and peat soil. The maximum population of earthworms was observed late October in the alluvial soil, early November in the peat soil, and late October in the volcanic ash soil. Their maximum biomass (wet weight) was observed in early October in the alluvial soil, early November in the volcanic ash soil, and late October in the peat soil. The population density was in the following order: peat>alluvial>volcanic ash, and the biomass was in the order: alluvial>peat>volcanic ash. © 1967, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.