In the context of increasing international concern for food and environmental quality, use of Plant Growth-Promoting Rhizobacteria (PGPR) for reducing chemical inputs in agriculture is a potentially important issue. PGPR are root-colonizing bacteria that exert beneficial effects on plant growth and development, but they can be also employed in the control of plant pathogens, for enhancing the efficiency of fertilizers, and for degrading xenobiotic compounds. This book provides an update by renowned international experts on the most recent advances in the ecology of these important bacteria, the application of innovative methodologies for their study, their interaction with the host plant, and their potential application in agriculture.

Soils are environments where a myriad of different organisms evolve, determining a series of functions which translate into ecosystem services that are essential for humanity. Improving our understanding of these organisms, their biodiversity and their interactions with each other, as well as with the environment, represents a major challenge. Soil ecology has its roots in natural history. The ecological approach focused on soils is notable for integrating, at least partially, the contributions of soil sciences (physics, chemistry, biochemistry). By renewing methods of observation and analysis (especially molecular ones) and through the development of experimental approaches and modeling, an ecology connected with other soil-based disciplines emerges and begins to influence aboveground ecology. Soils as a Key Component of the Critical Zone 6 presents an updated vision of knowledge and research in soil ecology as a complex system from the best French specialists.