Current Understanding of the Use of Alkaline Extractions of Soils to Investigate Soil Organic Matter and Environmental Processes

Abstract

A better understanding of soil organic matter (SOM) biogeochemistry is critical to meeting the environmental challenges that we face currently with the changing climate. Humic substances obtained from alkaline extractions of soils have played a predominant role in developing our knowledge of SOM chemistry and behavior during the 20th century. Recently, there have been new important developments that, according to some researchers, may be used to argue against the existence of the humic substances in soils as they are presently defined. A debate on the definition and continued use of the term “humic substances” has been taking place at conferences and in the scientific literature. However, because a consensus has not been reached on this important topic, the use of the term “humic substances” in this special issue conforms to the current existing definition of this term. This special issue of the Journal of Environmental Quality includes 10 papers on the subject of “Alkaline Extraction of Soils and Natural Waters to Understand Environmental Processes” and contributes to the ongoing assessment of the role of humic substances in current and future soil, environmental, and ecological studies. The contributed papers are grouped into three broad subject headings: (i) chemistry of humic substances, (ii) humic substances in environmental processes, and (iii) case studies and reviews of humic substances. Continued progress in understanding SOM and C biogeochemistry is essential to achieve long‐term ecological, environmental, and agricultural sustainability through the development of management strategies that conserve soil C and reduce the reliance on chemical inputs for meeting crop nutrient needs.Core Ideas This section aims to provide a wide‐ranging view of current humic substances research. Are humic substances appropriate proxies for soil organic matter? Better understanding of soil organic matter will enable future environmental sustainability.