The aim of this work was to examine the effects of long-term maize monoculture and crop rotation on biological activities of soil, especially soil enzymatic activities and microbial communities. We investigated the reaction of maize cultivated in perennial monoculture with direct sowing and compared it to full tillage monoculture and crop rotation full tillage cultivation in the following phases: six leaves, 12 leaves, flowering phase, before harvest, and after harvest. The results of the experiment conducted from 2004 to 2012 in the Experimental Station in Grabów (Mazowieckie Voivodship) on podzolic soil (very good rye soil), were the basis for this elaboration. Three objects were included in this research: maize cropped continuously (monoculture) with zero tillage, maize monoculture cropped continuously with full tillage, and crop rotation (spring barley, winter wheat, maize) with full tillage. The evaluation of the biological activity of the soil was based on the determination of the number of basic groups of soil microorganisms and enzyme activities. The maize was sown with the use of a seed drill. The statistically significant increase in soil enzymatic activity and total number of bacteria and actinomycetes in soil were observed where direct sowing in monoculture was implemented.