The influence of several physical indices of soil (bulk density, total porosity and compaction degree) on earthworm numerical abundance and biomass in a Chernozem (FAO System) was investigated in a six years crop rotation: Zea mays L., mixture of Medicago sativa L. and Dactylis glomerata L. (ratio 1:1), Triticum aestivum L., mash of Avena sativa L. and Pisum sativum L. (ratio 1:1), Zea mays L., mixture of Medicago sativa L. and Dactylis glomerata L. (ratio 1:1). The experimental field belongs to the Didactic and Experimental Station of the University of Agricultural Sciences and Veterinary Medicine of Banat, Timisoara, Romania. The experimental treatments consisted of control plots and plots organically fertilized with cattle manure in dose of 40 t ha -1. This fertilizer has been applied once every three years, as follows: in Zea mays culture in the first year and mixture of Avena sativa and Pisum sativum in the fourth year. Earthworms were extracted in mixed culture of Medicago sativa and Dactylis glomerata, in control and in experimental treatments, using 2% formaldehyde solution, according to specific methodology enounced by the standard ISO 23611-1/2006. The pedological descriptors of the soil profile were described according to the FAO System. Soil bulk density, total porosity and compaction degree were determined at two soil depths, 7-12 cm and 26-31 cm, respectively, reflecting the levels preponderantly populated by earthworms. Organic fertilization played a positive role not only in improving the physical properties of soil, but also in increasing the earthworm number. Thus, earthworm number increased with the decrease of the bulk density and compaction degree and became lower when the total porosity of soil decreased. Statistical relationships between all researched factors were investigated using the Pearson's method of correlation and the SPSS software. Both soil depths showed significant correlations ( p
