Frontiers in Soil Science Research: Report of a Workshop (2009)

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1 Introduction S oil is a biogeochemically dynamic natural resource that supports all critical components that comprise terrestrial ecosystems. It has been called Earth’s living skin. On its June 11, 2004, cover, Science declared soils to be “the final frontier.” The growing awareness that soil provides a variety of ecosystem services beyond food production has attracted interest in soil from nonsoil scientists. Collectively, soil is known as the pedosphere, and the processes occurring within soil are inextricably linked to ecosystem services such as water quantity and quality, are important in the exchange of atmospheric gases, and are central to the biogeochemical cycles of the nutrients and carbon that sustain life (see Figure 1-1). Soil supports the richest biodiversity on Earth and functions as a filter for, and a buffer of, inorganic and organic contaminants as well as pathogenic microorganisms and viruses. Despite the link between the quality of the soil resource and the rise and fall of world civilizations that has been repeated throughout history, soil remains an undervalued and underappreciated resource. There has been renewed interest in soil and soil science in recent years as the recognition that biogeochemical processes that occur at the Earth’s surface influence global climate change, land degradation and remedia- tion, the fate and transport of nutrients and contaminants, soil and water conservation, soil and water quality, food sufficiency and safety, global carrying capacity, wetlands function, and many other issues pertinent to the stewardship and conservation of land and water resources (special issue of Science, 2004). Population��������������������������������������������� pressure and associated changes in land use  

 FRONTIERS IN SOIL SCIENCE RESEARCH tion Atmosphere pre c ip ira ita sp t io re sis eva n e nth po sy ra emissions exchange gaseous to tio energy o ph n elemental soil cycling water Biosphere Pedosphere Hydrosphere soil flora evaporation & fauna formation leaching soil ro we ag ck e el a the e ep em rin &s ar ge en g off ch tal r un up r re tak ate e Lithosphere gr oun dw FIGURE 1-1 Interactive processes linking pedosphere with atmosphere, biosphere, hydrosphere, and lithosphere. SOURCE: Lal, Kimble, and Follett, 1997, 4. Reproduced with permission of Taylor & Francis Group LLC. Figure 1 completely redrawn based on Lal Rattan’s original broadside (landscape) place an increasingly high burden on editable vector, the global soil resource. In some areas of the Earth we have approached irreversible soil conditions that threaten the existence of future generations. Understanding the long-term implica- tions of decreased soil quality and addressing the aforementioned challenges will require new information based on advances and breakthroughs in soil science research that need to be effectively communicated to stakeholders, policy makers, and the general public. Soil science is an intrinsically interdisciplinary science that inte- grates knowledge of physical, chemical, and biological processes that �������������������������������������������������� interact across a large range of spatial and temporal scales. Soil scientists employ a multiscale approach—from the molecular to the landscape levels—to address issues related to biogeochemical reactions and pro- cesses in the environment, land use and degradation, regional and global climate change, food security, and water quality. There have been several National Research Council studies that identify areas in which opportu- nities for basic research in soil science are especially compelling. A report on the bioavailability of contaminants in soils and sediments noted the need for further research on how physical, chemical, and biological 

INTRODUCTION  processes in soil influence the bioavailability of chemicals (National Re- search Council, 2003). The report also noted the uncertainty related to variations in soil at various spatial scales, something that was discussed at this workshop. A Board on Agriculture report described the inherent link between soil and water quality, noting that soil productivity is not the only reason to protect soil resources (National Research Council, 1993). This report stated the need for research leading to the develop- ment of new technologies that protect soil and water quality. A report on metagenomics noted that this new science will draw on expertise from several disciplines, including soil science (National Research Council, 2007). Another report discussed the integrative studies of the “Critical Zone,” which encompasses the soil, rock, air, water, and ice at the Earth’s surface (National Research Council, 2001). The soil, or pedosphere, is the interface among the other components of the Critical Zone—the bio- sphere, hydrosphere, atmosphere, cryosphere, and lithosphere. As such, it is a major determinant of the global water, carbon, and geochemical cycles. Since soil represents a natural body covering essentially the entire nonaqueous surface of planet Earth, it is intimately involved in absorp- tion, storage, transfer, and release of heat, water, gases, and chemical constituents; serves as a reservoir for biological and microbial diversity; and, as such, has a profound influence on all living organisms. A report emanating from a National Science Foundation-sponsored workshop on the Critical Zone (Brantley et al., 2006) reiterated the im- portance of applying fundamental knowledge of soils to understanding the complex coupled hydrobiogeochemical processes occurring in the Critical Zone. Because of the central role of the pedosphere, it is clear that progress in understanding key processes in the Critical Zone is predicated on breakthroughs in soil science research. An understanding of critical soil processes and the ability to measure them is also central to other emerging research initiatives, such as the National Ecological Observatory Network. Soil science is at a critical threshold in identify- ing new areas for research. Emerging topics—such as climate change, carbon sequestration, water quality, vadose zone transport of nutrients and contaminants, biofuels, and food security—need strategic research on soil processes. New and emerging technologies and sensors are pro- viding unprecedented opportunities for revolutionary advances and breakthroughs in fundamental soil science research. These opportunities enhance problem-solving abilities and integrate knowledge from associ- 

 FRONTIERS IN SOIL SCIENCE RESEARCH ated disciplines (i.e., microbiology, hydrology, ecology, environmental science, geochemistry, geology, atmospheric sciences) to further unravel the mystery of soils and soil processes. As was noted in Science, “Inter- est in soil is booming, spurred in part by technical advances of the past decade” (Sugden, Stone, and Ash, 2004, 1613). On December 12-14, 2005, the National Academies convened the Frontiers in Soil Science Research Workshop to identify emerging areas for research in soil science by addressing the interaction of soil science subdisciplines, collaborative research with other disciplines, and the use of new technologies in research. The organizing committee for the workshop identified seven key questions that addressed research frontiers for the in- dividual soil science disciplines, but also addressed the need for integration across soil science and with other disciplines. The seven questions addressed by the speakers and discussants were as follows: 1. How well do we understand the physical, chemical, and bio- logical processes in soils that impact the atmosphere, vegetation, and the hydrogeosphere? 2. What are the chemical interactions at the molecular level that define the fate of ions, chemicals, and microbes as they are transported through soil systems? 3. What controls biodiversity belowground? How does this biodiver- sity affect the function of the soil system? 4. What is the effect of in situ soil architecture on soil physical, chemical, and biological processes? How does it vary from one soil system to another? What are the controlling factors? 5. How does landscape architecture (topography, vegetation, land use) affect the upscaling of soil processes to a regional level? 6. What are the new tools for making in situ and laboratory measure- ments of soil biological and physicochemical properties and processes? 7. From a systems analysis standpoint, what are the key indicators for detecting the resilience and stability of the soil system? What are the critical factors that control its resilience and stability? The committee then proceeded to identify potential speakers and dis- cussants for each of these seven questions, which addressed chemical, bio- logical, and physical processes, and their interactions. In choosing speakers and discussants, the committee looked for individuals who would be able 

INTRODUCTION  to address the questions from both a disciplinary and an interdisciplinary viewpoint. A particular strength of the workshop, as described by many attendees, was that the presentations cut across and integrated traditional subdisciplinary areas of soil science. The organizing committee purposely selected speakers for their abilities to cut across these lines and examine coupled hydrobiogeochemical processes. The workshop was not designed to identify specific issues within a subdiscipline. As part of the overall goal of the workshop to identify frontiers in soil science research, speakers, discussants, and attendees (the workshop was open to all interested individuals) were asked to consider overarching issues: • Main challenges and priorities within basic soil science research • Opportunities for inter- and cross-disciplinary research • Technological and computational opportunities to advance soil science research • Student and early career training issues At first glance, it may appear that the workshop did not explore par- ticularly “new frontiers” in soil science research. However, several attendees at the workshop commented that they were learning new ways to approach their own research. In many cases, the “frontier” may not be a specific tech- nology or technique new to the field, but expanded use of existing technolo- gies (i.e., tracers, spectroscopy, “omics”) within the soil science community. Many readers may find a new approach or technique with which they are not familiar or which they have yet to explore themselves. Although the original intent had been to also address the role of federal funding for research in soil science, the committee decided to not specifi- cally address funding issues to avoid discussion that would devolve into a plea for more funding from sponsors present at the workshop. However, there were discussions during the workshop that identified a lack of an ef- fective primary sponsor or steward of the soil science discipline and how this is problematic for maintaining strength in the discipline that could be leveraged in the interdisciplinary activities and opportunities in other funding agencies. To many people, including many in the federal funding agencies, soil science is still identified as a part of agricultural science only. Soil science is much more than this, integrating and drawing on many basic sciences as well as addressing societal issues beyond agriculture. Much of the discussion on the value of soil science research described in Chapter 2 arose 

 FRONTIERS IN SOIL SCIENCE RESEARCH because of the perceived lack of funding that many attendees believed was caused by a misunderstanding of how soil science research can contribute to other research areas, for example, environmental science, ecosystem services, and climate change science. The workshop consisted of an opening session with a keynote speaker, seven sessions focusing on the above questions with a presenter and discus- sants followed by general discussion, five breakout group discussions, and a final plenary discussion. Another key element of the workshop was the involvement of five graduate students who served as breakout rapporteurs and also presented posters on their own research. More than 120 people from various disciplines and from around the world attended the workshop. The president of the National Academy of Sciences, Ralph Cicerone, wel- comed the participants, noting the complexity of soils and the challenges facing soil science research. He noted that soil science was important to atmospheric scientists and other Earth scientists. This volume is a summary of the presentations and discussions at the workshop. The second chapter of this report addresses the need to place an economic value on soil science research. Although this was not one of the specific questions asked by the steering committee, it became clear dur- ing the workshop that this was a critical element to obtaining funding for soil science research, as noted above. The third chapter is a synopsis of the presentations, in the order they were made at the workshop. The fourth chapter details the research frontiers discussed at the workshop in the fol- lowing categories: (1) Overarching Challenges, (2) Research Needs and Opportunities (divided into six subcategories), (3) Tools, Techniques, and Current Opportunities, (4) Interdisciplinary Collaborations and Emerging Research Opportunities, and (5) Student and Training Issues. The report concludes with a brief epilogue, followed by three appendixes: the work- shop agenda, brief biographies of the speakers, and brief biographies of the steering committee. REFERENCES Brantley, S. L., T. S. White, A. F. White, D. Sparks, K. Pregitzer, L. Derry, J. Chorover, O. Chadwick, R. April, S. Anderson, R. Amundson. 2006. Frontiers in Exploration of the Critical Zone: Report of a workshop sponsored by the National Science Foundation (NSF), October 24-26, 2005, Newark, DE, 30 pp. Lal, R., J. M. Kimble, and R. F. Follett. 1997. Pedospheric processes and the carbon cycle. Pp. 1-8 in Soil Processes and the Carbon Cycle, R. Lal, J. M. Kimble, R. F. Follett, and B. A. Stewart, eds. Boca Raton, FL: CRC Press. 

INTRODUCTION  National Research Council. 1993. Soil and Water Quality: An Agenda for Agriculture. Wash- ington, DC: National Academy Press. National Research Council. 2001. Basic Research Opportunities in Earth Science. Washington, DC: National Academy Press. National Research Council. 2003. Bioavailability of Contaminants in Soils and Sediments: Processes, Tools, and Applications. Washington, DC: The National Academies Press. National Research Council. 2007. The New Science of Metagenomics: Revealing the Secrets of Our Microbial Planet. Washington, DC: The National Academies Press. Soils—The Final Frontier, special issue of Science, vol. 304, June 11, 2004. Sugden, A., R. Stone, and C. Ash. 2004. Ecology in the underworld. Science 304: 1613.