Mise en relation de la diversité des vers de terre et des caractéristiques du sol de Thua Thien Hue (Centre Vietnam)

The large proportion of sandy soils of Thua Thien Hue, in Central Vietnam, present a particular habitat for soil-inhabiting organisms among which earthworms represent close to 70% of total biomass. This study identified relationships between the characteristics of soil and earthworms. Our inventories yielded the presence of seven species of earthworms belonging to the families Glossoscolecidae, Megascolecidae and Microchaetidae. These were: Pontoscolex corethrurus, Glyphidrilus papillatus, Pheretima rodericensis, Pheretima danangana, Pheretima sp., Perionyx excavatus, and Lampito mauritii. Those of the Microchaetidae were present in acid soils with a high rate of silt and clay. Species in the other families were associated with poor but less acid sandy soils. This study also showed that the number of P. corethrurus was significantly higher in orchards while L. mauritii was significantly more common in soils with cultures other than rice. The species G. papillatus was significantly more abundant in fallow and was the only species found in this habitat. Highest earthworm diversity (Shannon-Wiener index(H=0.97)) was found in crops like manioc and sweat potatoes rather than in rice.