ABSTRACT
From the viewpoint of a soil chemist, the soil solution may be dened as “the aqueous liquid phase in soil with a composition that is in¥uenced by exchanges of matter and energy with soil air, soil solid phases, the biota, and the gravitational eld of the
12.8 Current Status and Future Research Directions .............................................................12-21 References .........................................................................................................................................12-21
earth” (Sposito, 2008). By dening it as a phase, Sposito implicitly requires that the soil solution has uniform bulk properties (such as composition and temperature) and can be isolated from the soil. ¤e requirement of uniformity can be met only on small scales of time and space because of the dynamic and spatially variable nature of soils.
