The influence of different land use management on the modification of the biological properties of leached chernozem located in the central zone of the Republic of Moldova has been investigated. Database of invertebrates, microorganisms and enzymatic activities has been formed. The current status of biota of the old-arable leached chernozem is characterized by the reduction in comparison with the level of the 1960s and with soil’s standards that are in conditions of natural ecosystems. The values of most soil biological indices decrease in the sequence: old fallow land → arable land under organic system with farming manure and incorporation of crop residues → arable unfertilized land → arable land with mineral fertilization of N90-300. The highest values of biota’s abundance were registered in fallow soils in the woodland belt and on plots with manure application with plant residues additives. Biological indices in soil profiles decreased with the depth and depended of the form of farming system. The negative effects on biota and humus status have been observed as a result of the long-term land management practices without organic fertilizers. Annual losses due to mineralization processes constitute 0.019%. The growth of humus-mineralizing microorganisms has been noticed. Trends and regression equations describing the growth of humus-mineralizing microorganisms and the fall of humus content in old-arable leached chernozems have been calculated.