Indicators for evaluating soil quality

Interactions between the diversity of primary producers (plants) and of decomposers (microbes and mesofaunal communities), the two key functional groups that form the basis of all ecosystems have major consequences on the functioning of agricultural ecosystems. Soil microorganisms control the transformation and mineralization of natural compounds and xenobiotics. The soil microbiota, existing in extremely high density and diversity, rapidly modify the energetic performance and activity rates to changing environmental conditions. Thus, the microbial consortium possesses the ability to accommodate environmental constraints by adjusting (i) activity rates, (ii) biomass, and (iii) community structure. These parameters are particularly important to take into consideration when evaluating soil quality. The present paper gives an overview about the possibilities to use bacterial and fungal populations as an indicator for soil quality. Furthermore also the applicability of nematodes for the determination of soil health will be discussed. (C) 2003 Elsevier Science B.V. All rights reserved.