Soil Physicochemical and Biological Interfacial Interactions in the Rhizosphere: Impacts on Food Security and Ecosystem Integrity

Abstract

The soil root interface (the rhizosphere) plays a vital role in sustaining life in the terrestrial ecosystem in the Earth’s Critical Zone (CZ). The CZ is defined as the volume extending from the upper limit of vegetation down to the lower limit of groundwater (Anderson et al., 2004). The CZ is the system of coupled chemical, biological, physical, and geological processes operating together to support life at the Earth’s surface (Brantley et al., 2007). While our understanding of this zone has increased over the last hundred years, further advance requires scientists to cross disciplines and scales to integrate understanding of processes in the CZ, ranging in scale from the mineral-organic matter-organism-water-air interfaces at a molecular level to the globe. Soil is the central organizer in the CZ. The rhizosphere is a hot spot of activity within soils. The rhizosphere is the ‘bottle neck” of the supply of vital elements to sustain ecosystem productivity and integrity and food security. The rhizosphere is also the “bottle neck’ of the contamination of the terrestrial food chain by inorganic and organic pollutants to endanger human and animal health.