Introduction The intensive farming system of the last decades had an unfavourable effect on the soil biological activity so on the quantity and quality of yield. Several specialists direct their attention to the biological farming system studying its effect on the yield and soil life. Experimental results from the long-term trial, comparing organic and conventional farming systems, showed that the activity of soil micro-organisms was higher in organic system, which helped to recycle nutrients faster and improve soil structure (Fliessbach et al., 2000). Stevlikova et al. (2002) found more intensive nitrification and higher microbial biomass-C content in an ecological farming system than in an intensive one. In the experiment of Lutzow et al. (1994) the microbial biomass-C content showed higher values in the ecological than in the traditional farming system. The aim of our paper was to study the effect of culture and liming within the ecological farming system, as well as the culture and fertilizer within the traditional farming system on some soil enzyme activities and microbial biomass-C content. These are considered the indicators of soil biological activity. We compare the biological activity of two farming systems too.