Promises of hydropedology

Integrative studies are needed as the response to mounting environmental challenges. The new discipline - hydropedology - has been defined as an intertwined branch of soil science and hydrology that encompasses the multiscale basis and applied research of interactive and hydrologic processes and their properties in the unsaturated zone. This review focuses on the relationship between soil structure and soil hydraulic functions at different scales, which is the distinct focus of hydropedology that makes it a desirable development for its parent disciplines. Status and perspectives are reviewed for revealing relationships between hydrologic functions of soils and soil structure at the aggregate/ped scale, the horizon/pedon scale, the field/hillslope scale and the watershed/basin scale. Transcending scales can be achieved by acknowledging that relationships between soil structure and hydrologic functioning at a particular scale are controlled by such relationships at a finer scale and greatly influenced by those at a coarser scale. Addressing soil hydrologic functioning at societally important scales can be achieved by applying data fusion, pedotransfer relationships, and concurrent use of models. Hydropedology emerges as the logical consequence of the progress in science and as the timely response to society's needs.