Relation between chemical indices of soil and earthworm abundance under chemical fertilization.

The study intended to establish how the dynamics of earthworms(Oligochaeta: Lumbricidae) changes in soil (abundance, biomass), under conditions of mineral fertilization with nitrogen and phosphorousin four different doses, in a 33-year experimental placement in the west of Romania, in wheat-soybean-maize-barley rotation. The soil indices taken into study were: pH, humus, total nitrogen, phosphorousand potassium. Statistical connections between the studied factors were realized using the dispersion analysis ANOVA and the SPSS Software (Statistical Package for the Social Sciences). The study showed an increase of earthwormabundance and biomass under condi tions of chemical fertilization with nitrogen and phosphorous. The highest number of earthwormswas recorded in the treatment with the largest dose of nitrogen fertilizer (by 85.85% higher compared to the control treatment). The greatest positive influence on earthwormabundance and biomass was manifested in humusand total nitrogen. The greatest negative influence on earthwormabundance was found in pH factor, while phosphorouscontent of soil ex erted the greatest negative influence on earthwormbiomass.