Emerging issues and research opportunities in vadose zone processes
Ryan D. Stewart, Markus Flury, Hoori Ajami, Ray G. Anderson, Timothy R. Green, Yan Jin, Andres Patrignani, Rose Shillito, Wei Zhang, Majdi Abou Najm, Ebrahim Babaeian, Markus Berli, E. N. Jack Brookshire, Aaron Lee M. Daigh, Shane Franklin, Jeremy Giovando, Robert Heinse, Joshua L. Heitman, Jingyi Huang, T. J. Kelleners, Mahyar Naseri, Tyson E. Ochsner, Jesse Radolinski, Morteza Sadeghi, Salini Sasidharan, Manoj K. Shukla, Markus Tuller, Ole Wendroth, Joan Q. Wu, Briana M. Wyatt, Yang Yang, Yingxue Yu, Z. Fred Zhang
Abstract
Abstract The vadose zone—the variably saturated, near‐surface environment that is critical for ecosystem services such as food and water provisioning, climate regulation, and infrastructure support—faces increasing pressures from both anthropogenic and natural factors, including changing climatic conditions. A more comprehensive understanding of vadose zone processes and interactions is imperative to effectively address these challenges and safeguard water and soil resources. This review outlines selected key issues, knowledge gaps, and research opportunities across six thematic sections. Each section presents a problem statement, a summary of recent innovations, and a compilation of emerging challenges and study opportunities. The selected topics include scaling and modeling of vadose zone properties and processes, soil moisture monitoring initiatives, surface energy balance, interplay between preferential water flow paths and biogeochemical processes, interactions between fires and vadose zone dynamics, and emerging contaminants and their fate in the vadose zone. This overview is intended to serve as a compendium of vadose zone science that encompasses both insights gained from prior research and anticipated needs for the coming years.