The Role of Critical Zone Science in Promoting Environmental and Agricultural Sustainability.

The  Critical Zone is that region of Planet Earth that extends from the top of trees to the groundwater.  It  sustains life.  The critical zone  encompasses a range of spatial and temporal scales, and includes coupled physical, chemical, and biological processes.  Critical zone science is thus extremely multidisciplinary involving not only soil scientists but also geomorphologists, hydrologists, ecologists, molecular biologists, geochemists, mineralogists, material scientists and engineers, and social scientists. Critical zone science addresses some of our most pressing global challenges including population expansion and food production/security, water quantity and quality, air quality, soil contamination, global climate change, energy sustainability, and biodiversity.   There is a growing network of critical zone observatories where exciting  science to address these challenges  is being conducted. This affords USA and Chinese soil scientists the opportunity to collaborate. Some examples of  existing and potential collaborations will be discussed.