The biota’s state of the ordinary chernozem located in the southern zone of the Republic of Moldova has been investigated. Arable chernozems with different degrees of erosion (slightly, moderately and severely eroded) have been compared to the chernozem with the normal profile and eroded soil which was under 58 year’s old fallow. The biological degradation of soils occurred as a result of water erosion processes. The parameters of the biota very depending on the erosion degree and decrease in the following sequence: chernozem with the normal profile → slightly eroded chernozem → moderately eroded chernozem → severely eroded chernozem. Losses of microbial carbon amount to 107-248, 305-433 and 513-535 kg C ha-1 according to the erosion degree. The loss of species and families of invertebrates in moderately and severely eroded chernozems is of 63 - 100%. Diversity of the Bacillus family decreased from 14 species to 7 - 10 species. The decline of enzymes activities in moderately and severely eroded chernozems reaches 29.2-55.6% for dehydrogenase and 85.7-94.3% for urease. A scale of biological parameters has been proposed to assess the stability of biota of the ordinary chernozem and to develop the national soil quality standards. The recovery rate of the biota and fertility of eroded arable chernozems that moved to the category of fallow soils has been determined. In this context, the management of fallow land areas has been recommended aiming to regenerate the edaphic fauna and microorganisms and to restore the natural quality of eroded chernozems.