ABSTRACT
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Changing conditions of local and global markets are pressing farmers to achieve
ever-increasing crop productivity together with improved quality of their agricultural
products. To reach these objectives, adequate plant acquisition of nutrients is necessary.
However, even when nutrients are provided externally, their utilization by plants is
highly dependent upon the physical, chemical, and especially biological conditions in
the soil that is located in the immediate vicinity of plants’ roots, known as the rhizosphere.
This layer of soil, just a few millimeters thick, is intimately and continuously affected
by roots’ metabolic processes, creating a zone of intense activity quite different from
the surrounding bulk soil. The rhizosphere’s contribution to soil systems’ fertility and
sustainability and, thus to optimal plant growth, is all out of proportion to its physical
volume.
