Earthworm casts and their surrounding topsoil were taken in collaboration with the Soils and Fertilizers Research Institute (SFRI) under different vegetation cover at the long term observatory catchment of Dong Cao in Northern Vietnam in 2017. This dataset holds general chemical parameters of soil samples. Dry combustion analysis (CHN) was used to assess organic Carbon (TOC) and Nitrogen (N) concentrations. Potassium dichromate oxidation titration was as well used to quantify organic Carbon (TOC). Natural isotopes Carbon-13 (13C) and Nitrogen (15N) were analyzed by mass spectrometry. Soil analyses have been carried out at the "Pôle d’expérimentation et d’analyse des sols et sédiments tropicaux" (ALYSÉS) and at the soil chemical laboratory of the Soils and Fertilizers Research Institute (SFRI). The collection of the data was supported by CNRS/INSU (VINAWORM) research program under the framework of the EC2CO program.