Living soils : Foundation of better agricultural practices

Soil is often viewed as a physical substrate that performs a wide range of functions that also go beyond agriculture. It regulates water, sustains plant and animal life, recycles organic wastes, cycles nutrients, filters out pollutants, and serves as a physical support for structures. Yet, soil is also a living entity in itself, containing an enormous number of organisms, and vast biodiversity. One gram of good soil contains millions of organisms, including several thousand different species. They range in size from the tiniest one-celled bacteria, algae, fungi and protozoa, to the more complex nematodes and arthropods, and to the visible earthworms, termites, insects, small vertebrates and plants. This community of organisms makes up a "soil food web' densely packed in the upper layers of the soil. (Editorial)