Interactions Between Mycorrhizal Fungi and Bacteria to Improve Plant Nutrient Cycling and Soil Structure

Abstract

The stability and productivity ofeither agro-ecosystems or natural ecosys- tems largelydependonsoil quality, therefore, themanagement ofsoil–plant systems must consider the maintenance of the quality and sustainability of soil resources (Altieri 1994). An important issue is that soil quality is fun- damental not only to produce healthy crops or to ensure self-sustainability of the ecosystems, but also to prevent erosion and to minimize environ- mental impacts (Parr et al. 1992). Soil quality is determined by diverse chemical, physical and biological factors and their interactions. Thus, for the appropriate management of soil–plant systems, the understanding of how the physicochemical and biological (microbial) components function and interact, and how perturbations affect these interactions is critical (Kennedy and Smith 1995). Actually, perturbations of either agro- or nat- ural ecosystems are known to disturb interactive processes which affect essential determinants of soil quality, such as soil structure, plant nutrient availability, organic matter content and/or microbial diversity and activ- ity (Kennedy and Smith 1995). Therefore, the success of any restoration approach largely depends on the integration ofmanagement strategies ad- dressed to optimize the interactions among the soil components improving its quality (Requena et al. 2001).