4
The Frontiers in Soil Science Research

All of the speakers and participants in the workshop were asked to consider the following:

  • 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

The main ideas that came out of the presentations, the discussions, and the breakout groups are summarized below in five sections: (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.

OVERARCHING CHALLENGES

Throughout the workshop, two main challenges were frequently mentioned. One was the need to place a value on the soil resource and give the soil science discipline societal relevance by relating it to global issues such as food and energy security, human health, and environmental sustainability. This topic was addressed in Chapter 2 of this report.



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4 The Frontiers in Soil Science Research A ll of the speakers and participants in the workshop were asked to con- sider the following: • 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 The main ideas that came out of the presentations, the discussions, and the breakout groups are summarized below in five sections: (1) Over- arching 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. OVERARCHINg CHALLENgES Throughout the workshop, two main challenges were frequently men- tioned. One was the need to place a value on the soil resource and give the soil science discipline societal relevance by relating it to global issues such as food and energy security, human health, and environmental sustainability. This topic was addressed in Chapter 2 of this report. 

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 FRONTIERS IN SOIL SCIENCE RESEARCH The second main challenge, which is also a research frontier, was that of scale. Several of the speakers addressed the topic, introducing the need to consider both spatial scale (from the molecular level to landscape and beyond) and temporal scale (across time and also across processes that oper- ate at different speeds). For example, Session 2 included discussion on using microscopic and spectroscopic techniques to elucidate physical, chemical, and biological processes at the microscopic level to understand impacts at the “field scale.” Session 5, “Upscaling to a Regional Level,” considered the roles of landscape structure and remote sensing in translating soil processes from the laboratory to the field and regional scales. Both sessions addressed the issue of temporal scale. At one end of the scale, Don Sparks noted in Session 2 that there are processes that happen within nanoseconds and cannot be measured. At the other end of the spectrum, César Izaurralde and others noted that some landscape processes occur over geologic scales beyond human perception. Scaling up of processes, rather than simply scaling up of properties, by soil scientists is particularly understudied, and soil scientists are often uncomfortable in doing so, as noted by one of the breakout groups. Soil scientists must focus on research at multiple scales ranging from nanometers to watersheds. While small-scale research is often interesting and more likely fundable, large-scale research is needed to translate small-scale research to appropriate societal and global issues. The ability to “scale down” is also needed and tractable by soil scientists. For example, the effects of global climate change on specific regions or landscapes can be translated at a scale that society and managers can understand and act on. The notion of a coordinated “grand experiment” was discussed to facilitate soil scientists in addressing the issue of scaling. Overarching challenges: • Placing a value on the soil resource • Integrating research from different spatial and temporal scales

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 THE FRONTIERS IN SOIL SCIENCE RESEARCH RESEARCH NEEDS AND OPPORTUNITIES Ecosystem Functioning As was described extensively in Chapter 2, there is a need to develop methodologies for valuing, both financially and culturally, ecosystem services provided by soil. However, to do this, identification and quanti- fication of the key ecosystem services performed by soil is needed, as was noted by Kate Scow in the last presentation. Several speakers—including Fendorf, Pierzynski, Sparks, and Tiedje—discussed the need to develop measurements that extrapolate to the ecosystem scale both spatially and temporally. A future growth need stressed by workshop participants was the development of appropriate indicators of soil function to allow for the anticipation of degradation. Opportunities were mentioned for the application of soil science research to urban ecosystems. Long- term monitoring is needed to quantify global dynamics rather than static soil properties so that the resulting measurements can be more meaningful. Ecosystem functioning research needs: • Identify and quantify key ecosystem services provided by soil • Measure the value of ecosystem services performed by soil • Develop measurements to extrapolate to the ecosystem scale • Develop appropriate indicators of soil function • Long-term monitoring to quantify global dynamics • Incorporate soils into studies of urban ecosystems Role of Soils in Human Health There is a general need to characterize the relationship between soil quality and human health, including processes at the landscape scale. For example, the relationship between the transport of biologicals and their fate in soil and human health issues needs to be explored. There is a need to understand the effect of land management on the fate and transport of com- pounds and organisms that affect human health. The topic of desertification

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 FRONTIERS IN SOIL SCIENCE RESEARCH and resulting effects of soil particulates on human health was identified as a research need. There are also less direct links that need further explora- tion, such as the role of soil on water quality, and indirect links, such as soil and environmental quality. Human health research needs: • Characterize the relationship between soil quality and hu- man health • Relate virus transport and fate in soil to human health • Characterize the effect of soil particulates from desertifica- tion on human health • Characterize the role of soil quality in water quality and its effect on human health Transport Processes To better interface within the soil science community and with other sciences, it is important to understand transport processes in soil and to scale up to global processes. For example: (1) the characterization of gas fluxes to the atmosphere in relation to climate change; (2) the effect of water flow through the soil column on the hydrosphere; (3) how this flow is scaled up to a complex landscape; and (4) the impact of the transport of viruses and other microorganisms in soils on human health. There is a need for studying the interaction of physical transport through soil with microbial or chemical processes. There needs to be better characterization of transport and reactions by exploring, for example, the use of in situ tomographic and spectroscopic techniques. Research at interfaces between soil and the atmosphere, hydrosphere, lithosphere, and biosphere is a need noted by many speakers (Trumbore, Izaurralde, Fendorf, Young, and Tiedje). Greater use of tracer techniques provides an opportunity to characterize the interactions between the “spheres” as discussed by Trumbore. The role of colloids as facilitators of transport of natural material and contaminants and as accelerators in soil formation was identified as a research opportunity during the breakout session. In addition, small-scale experiments should be better related to the natural environment (landscape scales). It was noted that there are opportu-

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 THE FRONTIERS IN SOIL SCIENCE RESEARCH nities to combine geomorphological landscape analysis and remote sensing techniques to facilitate scaling. Transport processes research needs: • Research transport processes at interfaces between soil and atmosphere • Characterize gas fluxes to the atmosphere in relation to climate change • Characterize the impact of water flow through the soil column on the hydrosphere • Identify the impact of the transport of viruses and other microorganisms in soils on human health • Employ in situ tomographic and spectroscopic techniques to characterize transport and reactions • Characterize reactions at the interface of the various “spheres” • Research the role of colloids as facilitators of transport Plant-Soil-Microbial Interface Basic research at the plant-soil-microbial interface is needed, includ- ing a particular emphasis on applying modern genomics techniques as noted by several speakers. The role of plant-soil-microbial interfaces on nutrient cycling needs to be characterized. The need to better under- stand the effect of biofilms was noted in Sessions 2 and 3 as well as in several breakout groups. The biofilm-microbe surface interaction and biotic interaction at surfaces relates to geochemical cycling processes, not just to nutrient cycling. It was noted that the plant-soil interface relates to soil formation, that is, the role of interfaces in controlling rates of weathering. Similarly, Young emphasized how soil architecture and the properties of soil surfaces, such as hydrophobicity, are greatly influenced by microbial activities occurring at plant-soil-microbial interfaces. Fen- dorf expressed the need to understand the role of plant-soil-microbial interfaces in contaminant fate.

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 FRONTIERS IN SOIL SCIENCE RESEARCH Interfacial research needs: • C onduct basic research at the plant-soil-microbial interface • Apply genomics techniques • Characterize the role of interfaces on nutrient cycling, in contaminant fate, and in weathering processes • Research the role of biofilms in geochemical cycling processes Characterization of Coupled Reaction Processes in Soil A general need raised throughout the workshop was that of a better understanding of feedback mechanisms between physical, chemical, and biological processes. Young noted that in situ techniques could help provide that understanding. Other speakers, notably Fendorf, Sparks, and Tiedje, discussed how the integration of in situ physical, chemical, biological (omics), and imaging techniques could be used to elucidate the coupling of soil processes. The tools exist, but integration is needed. As was noted in one of the breakout groups, it is important to empha- size and understand that reactive phases are dynamic. Research opportuni- ties that were brought forth were feedback mechanisms among linked soil processes and improved characterization of the dynamics and coupling between physical, chemical, and biological soil processes. Young noted the need to understand the feedback mechanisms between biotic activity and soil architecture. There is also a need to characterize the reaction of soil to external perturbations from climate, as well as the long-term stability and resilience of soil experiencing degradation from human activity. Coupled reaction processes research needs: • Employ in situ imaging techniques • Understand dynamic reactive phases • Improve characterization of the dynamics and coupling between physical, chemical, and biological processes • Improve the understanding of feedback mechanisms be- tween physical, chemical, and biological processes

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 THE FRONTIERS IN SOIL SCIENCE RESEARCH • Characterize the reaction of soil to external perturbations from climate or change • Characterize long-term resilience of soil experiencing degradation from human activity Data Acquisition and Synthesis Throughout the workshop, discussion included how data are acquired, assimilated, and integrated. For example, it was suggested that existing pools of data be organized and standardized to permit improved interchange among scientists across disciplines. Data from long-term studies could be synthesized and analyzed to improve and update future monitoring practices. As mentioned above, the integration of in situ physical, chemical, bio- logical (omics), and imaging techniques is needed to elucidate soil processes. James Tiedje suggested expanding omics studies on important soil bacteria to discern and investigate genes relevant to soil ecology. He also noted that metagenomics (the community genome) could be used to reduce the com- plexity of information for a given microbial community for use by other soil science disciplines. There is a need to interface the interpretive expertise of soil scientists with the expanding efforts and new initiatives in metagenom- ics to better identify the questions and strategies that will help minimize complexity issues in the soil and to enhance interpretive capabilities. Upscaling of soil processes requires improved data acquisition and improved modeling. In his paper, César Izaurralde stated, “Data acquisition and avail- ability has been a key impediment for applying models across spatial scales.” Remote sensing and geographic information systems (GIS) at various scales combined with interactive computer models were noted as needs. Susan Moran noted that “the biggest breakthrough in upscaling of soil models he to a regional level will be made when satellite-derived model parameters are available for free to everyone.” Henry Lin noted in his discussion paper that pattern recognition or “spatial-temporal organization” may improve the understanding of soil variability. New measurement technologies will aid in upscaling processes. For example, the potential for using laser-in- duced breakdown spectroscopy, mid- and near-infrared spectroscopy, and inelastic neutron scattering to monitor soil carbon levels is currently being explored.

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 FRONTIERS IN SOIL SCIENCE RESEARCH Data research needs: • Standardize and synthesize existing databases and improve access • Integrate in situ physical, chemical, biological, and imaging techniques • Improve modeling across spatial and temporal scales • Develop new measurement techniques TOOLS, TECHNIQUES, AND CURRENT OPPORTUNITIES One of the goals of this workshop was to identify tools and tech- niques—some already in use by other disciplines, some new—that could be applied to soil science research. Although many soil scientists already use some of these tools (for example, many soil scientists are already using synchrotrons), more soil scientists need to be made aware of them and how to use them. Several attendees at the workshop expressed their desire to learn more about the tools and techniques they were hearing about, some for the first time. The integration of new techniques and tools such as third-generation light sources with multiple scientific disciplines provides new and exciting opportunities for addressing a variety of highly relevant soil science issues, as presented by Kenneth Kemner. The integration of the strengths of both X-ray and electron microscopies to investigate geomicrobiological systems is especially promising. Hard X-ray micro(spectro)scopy offers many excit- ing possibilities for future environmental and biogeochemical soil science investigations. The use of geospatial technology to better understand soil was demonstrated in Session 4. In his presentation, Iain Young used a three- dimensional display that got all workshop participants interested in—and excited about—how to use such a tool in their own research. The de- velopment and use of nondestructive imaging methods to characterize and three-dimensional soil structures of nondisturbed soil horizons, and the development of dynamic flow theory that transforms three-dimensional soil architecture into function is a frontier research area. Such spatial informatics can be applied at multiple scales.

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 THE FRONTIERS IN SOIL SCIENCE RESEARCH In her presentation, Susan Trumbore discussed the use of isotopic tracers as a soil science research tool and emphasized that some powerful opportunities exist today but will not be available in the future, for example, isotopes of carbon and cesium as a result of aboveground weapons testing. In addition, several needs or research gaps were identified during the pre- sentation and the following discussion. How can tracers be effectively used to address a series of questions that quantify state factors in soil? How can interactions among the physical, biological, and chemical processes within soil be quantified across a range of ecosystems? What new insights into soil processes can be gained through application of isotopic tracers to soils? Microscopic and spectroscopic techniques need to be applied for improved understanding of coupled processes in soil, as noted by Scott Fendorf in his presentation. He also noted that we are on the leading edge of efforts to develop conceptual and mathematical models based on molecular-level data that will facilitate the generalization of processes from individual studies. Throughout the workshop, the need for the development of more tools for use in soil science research was identified. Further advances in soil science could be accomplished with tools that allow for in situ studies of the chemistry, structure, and biology of soil. There is a need for improved modeling techniques that allow for extrapolating experiments across scales and techniques to capture the variability and heterogeneity related to the function and processes of soil. Related to this is the need for a greater use of mathematical and computational capabilities. And, as noted above, a greater use of geospatial technology, along with GIS and remote sensing, can lead to breakthroughs in soil science research. The development of computational methodologies could help address complexity problems such as heterogeneity, variability, and scaling, as noted in Session 3. Furthermore, new techniques characterizing mineral surfaces could contribute to understanding microbial interactions with charged surfaces and help create bridges between soil chemistry and soil biology. In addition to using already existing tools, new tools do need to be de- veloped. The challenge is to make more soil scientists aware of these existing and emerging tools and techniques and how to use them for their research. One way to do this is to encourage collaboration of soil scientists with the scientists in other disciplines who are either developing these tools or are using them for their own research.

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0 FRONTIERS IN SOIL SCIENCE RESEARCH Research opportunities using new tools and techniques: • Encourage greater employment of micro(spectro)scopy by soil scientists • Employ isotopic tracers in soil science research • Develop new tools for in situ studies of the chemistry, struc- ture, and biology of soil • Improve modeling techniques for extrapolating across scales • Employ more mathematical and computational capabilities in modeling • Employ modeling to transform architecture into function INTERDISCIPLINARY COLLABORATIONS AND EMERgINg RESEARCH OPPORTUNITIES Soil science is intrinsically an interdisciplinary science that integrates physics, chemistry, biology, geology, and computational sciences. Soil scientists have long been at the forefront of applying state-of-the-science technologies and methodologies to complex environmental systems. Per- haps “soil system science” would be a more effective term to describe the transformations that this discipline has already undergone and will continue to undergo. As was seen in several of the workshop presentations (Fendorf, Young, and Kemner, in particular), the advances in separation, spectroscopic, and imaging technologies in recent years have resulted in major breakthroughs in understanding complex physical and chemical properties of soil that con- trol the fate and transport of fluids, nutrients, carbon, and contaminants. Furthermore, the revolution in molecular biology and the fusion and inte- gration of rapidly advancing analytical and molecular biological methods are enabling key biogeochemical processes to be probed at very high reso- lution at submicron to millimeter scales. The integration of this physical, chemical, and biological information collected in situ with these advanced techniques will provide an unprecedented opportunity to understand how physicochemical and biological processes are coupled and to elucidate vari- ous feedbacks that are operating in complex environmental systems. There has never been a period where revolutionary breakthroughs in

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 THE FRONTIERS IN SOIL SCIENCE RESEARCH understanding soil and the hydrobiogeochemical processes occurring within soil are so likely. As was noted by several participants in the workshop, these breakthroughs will only be possible if soil scientists greatly expand their collaborative efforts with colleagues in other scientific disciplines to bring the most advanced techniques and approaches to bear on unraveling the mechanisms underlying key physical, chemical, and biological processes; understanding how these processes are coupled; as well as the feedback sys- tems operating across temporal and spatial scales. Brent Clothier noted in his presentation that the complete scientific study of soil requires researchers from a wide range of disciplines. Breakthroughs in soil science will require mathematicians, physicists, chemists, and biologists to work together, and for them to link with economists and sociologists. Breakthroughs and in- novations will come from the synergy of collaboration and from research at the interfaces between disciplines. . In addition to areas of research, it is helpful also to consider the ways in which the conduct of research may be most effective in the future. Iain Young assembled a diverse group of 23 young scientists at the Scottish In- In- formatics, Mathematics, Biology, and Statistics (SIMBIOS) Centre (based SIMBIOS) at the University of Abertay, Scotland). The group has expertise in a wide . variety of fields: experimental soil mechanics, mycology, cell biology, com- putational fluid mechanics, statistical mechanics, theoretical biology, plant physiology, computer gaming, and information technology. This forms a flexible, interdisciplinary research team that can tackle soil problems in an innovative manner, not being bound by traditional approaches. They work together in an open environment without doors, creating synergy and op- portunities for serendipity. This work-model is not new in general, but it is for the soil science community and presents an intriguing approach to solving problems in the future. New areas of collaboration need to be more aggressively pursued. For example, the role of soils in human health had been traditionally thought to be tied to food supply, nutrition, and water quantity and quality. However, many additional aspects are involved, including the role of soil in exposure pathways to contaminants and pathogens and the involvement of soil in emerging diseases. Informatics is another area where stronger collabora- tions between soil scientists and colleagues from other disciplines will be required. Integrating advances in bioinformatics, spatial informatics, and ecoinformatics, as well as molecular modeling will be critical to advancing soil science research and will demand new collaborations. Another emerging area identified by workshop participants was the area of urban soils. While

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 FRONTIERS IN SOIL SCIENCE RESEARCH soil science research has traditionally focused on wildland and managed for- est ecosystems and agricultural soils, many problems and issues surrounding the urban soil resource require attention and provide opportunities for soil scientists to work with engineers and others to address these issues. It was clear from the workshop that, while many soil scientists are at the leading edge of utilizing the most advanced techniques and approaches through col- laborative efforts, there needs to be much greater effort in making the tools and approaches more widely available and collaborations with colleagues in other disciplines more mainstream. Workshop attendees, many of whom were unfamiliar with the advanced tools, techniques, and approaches avail- able, expressed enthusiasm to collaborate with other colleagues. Other emerging interdisciplinary research opportunities for soil scientists involve Earth-observing systems. Workshop participants men- tioned several major new research initiatives funded by the National Sci- ence Foundation, such as the National Ecological Observatory Network (NEON), the Collaborative Large-scale Engineering Analysis Network for Environmental Research (CLEANER), and the Consortium of Universities for the Advancement of Hydrologic Sciences, Inc. (CUAHSI), that involve measurement of soil properties and processes over large spatial and temporal scales. The NEON will be the first national ecological measurement and ob- servation system designed both to answer regional- to continental-scale sci- entific questions and to have the interdisciplinary participation necessary to achieve credible ecological forecasting and prediction. The CLEANER and CUAHSI programs are planning a dual-purpose network called the Water and Environmental Research Systems (WATERS) Network. The WATERS Network is proposed as a networked infrastructure of environmental field facilities working to promote interdisciplinary research and education on complex, large-scale environmental systems. While many in the soil sci- ence community have been involved in the planning and execution of these major interdisciplinary research initiatives, more soil scientists have to become involved to ensure that the role of soil is properly appreciated up front and that appropriate measurements of soil properties and processes are integrated into the observatory and experimental platforms. Several presenters and participants noted that there are major chal- lenges in scaling up from understanding mechanisms involved in coupled hydrobiogeochemical processes in soil that control the fate and transport of water, nutrients, carbon, contaminants, and pathogens to addressing issues manifested at larger scales. The link between key soil processes and critical ecosystem services needs to be more firmly established, as does the value of

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 THE FRONTIERS IN SOIL SCIENCE RESEARCH these services, as was discussed in Chapter 2. Additionally, the importance of the soil resource as the foundation of terrestrial ecosystem health, water resources, global carbon budgets, and global biogeochemical cycles needs to be better articulated to policy makers and members of the general public. To address these larger-scale issues and to properly integrate advances and breakthroughs in soil science research into policy will require collaborations with colleagues in the social sciences, humanities, and economics. Jayne Belnap, in discussing the final presentation, stressed how soil sci- entists must collaborate with others to make them aware of the importance of soils. Soil scientists need to be active collaborators and not expect those from other disciplines to come to them if they are not reaching out to other scientists. Attending meetings of other related disciplines is important to raise awareness of the relevance of soil science to those other disciplines. Equally important is understanding how to make soil science relevant to the audience being addressed, whether it is that of another scientific discipline or stakeholders, end users, or policy makers. Opportunities for soil science in interdisciplinary collaborations: • Research at the interface of disciplines could lead to breakthroughs • Consider new models for interdisciplinary collaboration • Participate in Earth-observation systems and other new multidisciplinary research initiatives • Collaborate with colleagues in social sciences, humanities, and economics to integrate advances and breakthroughs in soil science research into policy making STUDENT AND TRAININg ISSUES Throughout the workshop, participants were asked to consider whether there were any issues related to education and training that needed to be addressed for soil science to reach new frontiers in research. Several gener- alities were made in the discussion periods and breakout groups; many of these echo the challenges raised under other subheadings: teach students to work across the discipline and with other disciplines; provide internships to work with new tools and techniques; train students to understand the

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 FRONTIERS IN SOIL SCIENCE RESEARCH societal relevance of their research; teach the capacity to communicate with nonscientists. During one breakout session, it was noted that there has been a para- digm shift in the approach to soil science research that affects how soils should be taught, but the soil science curriculum has not undergone the same change. Many soil science departments have become part of larger programs with labels such as environmental science. This may attract more students, but some scientists question whether it dilutes the fundamentals of the discipline. Collaboration with other departments is necessary, how- ever, to allow students to be involved in interdisciplinary opportunities and have access to high-tech instruments not found in most soil science depart- ments. Ways to introduce undergraduates in other disciplines to soil science were discussed in several breakout groups, such as research experiences and summer field courses. The issue of certification and licensing was also discussed during the breakout sessions. Engineers and geologists, who are licensed and certified, work in environmental consulting. Soil scientists are not being extensively involved in much of this work, and the work may be suffering by not hav- ing greater involvement by soil scientists. There is voluntary certification for soil scientists, and some states have licensing of soil scientists, but this is not widespread. Issues in student training: • Teach students to – collaborate across disciplines – think at larger scales – relate to the general public • Provide interdisciplinary opportunities • Collaborate with other departments to give students access to high-tech instruments