ABSTRACT
Nutrient dynamics in agricultural soil is driven by the same mecha nisms as those subtending nutrient dynamics in undisturbed soil ecosys tems. In all ecosystems, soil is similarly made of solids and of pores that are occupied by air and by the soil solution. The solid component of soils comprises a mineral fraction intimately bound with humified or ganic matter (OM), fresh OM and living organisms. Energy flowing within such organized matrix sustains life in natural and agricultural systems too. Most importantly for plants, which need mineral nutrients to build themselves, this energy flow permits transformation of matter. Soil organisms, which act as catalysts of this transformation, helps re plenish the soil solution with ions several of which are required by plant. Soils can be seen as the dark interface where the mutual influence
of the biotic and abiotic components of Earth results in the dissolution of the very substance of the planet into ions, which cycle intensively be fore being lost from the soil systems through leaching, volatilization or crop removal. This is largely how plants are fed and how soils evolve.
