Understanding soil processes: one of the last frontiers in biological and ecological research

Soils are one of the great unknown realms on earth, despite decades of extensive research. We still see soils "through a ped darkly". This opacity in milieu and understanding rewards innovative study, however, as soils are indeed "complex adaptive systems", and show very sophisticated levels of self-organization. Viewed historically, soil ecological studies have progressed from what major groups of biota are present, what is their biomass, and what major processes occur. More recent studies have delineated multi-trophic interactions, extending both above- and below-ground, as well as specifically-targeted studies of substrates and organisms that are involved in the development and function of suppressive soils. One of the great unknowns in soil ecology is a fuller understanding of the complete array of predatory biota. Soils are teeming with organisms in all three Domains, but are also rife with many viruses infecting Archaea, Bacteria and Eukarya, meaning that they need more study in soil processes. Pursuing a more holistic approach including viral biology and ecology may enable us to more capably manage our soils that have supported the biosphere so much over the millennia. Looking into the future, the opportunity to exploit soil biodiversity in the context of ecosystem development should pay considerable dividends. Using chronosequence analysis, the relationships between soil biodiversity and ecosystem function are beginning to be understood. The interplays of aboveground and belowground herbivores on plant function and feedbacks on the attraction of the herbivores' natural enemies. Finally, management of the plant-soil-microbial-faunal system via varied organic amendments shows possibilities in the study and management of suppressive soils.