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Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2024. Exploring Linkages Between Soil Health and Human Health. Washington, DC: The National Academies Press. https://doi.org/10.17226/27459.

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COMMITTEE ON EXPLORING LINKAGES BETWEEN SOIL HEALTH AND HUMAN HEALTH

DIANA H. WALL (Chair),¹ Colorado State University, Fort Collins

KATRINA ABUABARA, University of California, San Francisco; University of California, Berkeley

JOSEPH AWIKA, Texas A&M University, College Station

SAMIRAN BANERJEE, North Dakota State University, Fargo

NICHOLAS T. BASTA, Ohio State University, Columbus

SARAH COLLIER, University of Washington, Seattle

MARIA CARLOTA DAO, University of New Hampshire, Durham

MICHAEL A. GRUSAK, U.S. Department of Agriculture–Agricultural Research Service, Fargo

KALMIA E. KNIEL, University of Delaware, Newark

YLVA LEKBERG, MPG Ranch; University of Montana, Missoula

REBECCA NELSON, Cornell University, Ithaca

KATE M. SCOW,^1,2 University of California, Davis (emerita)

ANN SKULAS-RAY, University of Arizona, Tucson

LINDSEY SLAUGHTER, Texas Tech University, Lubbock

KELLY WRIGHTON, Colorado State University, Fort Collins

Study Staff

KARA N. LANEY, Study Director

ROBERTA A. SCHOEN, Board Director, Board on Agriculture and Natural Resources

ANN L. YAKTINE, Board Director, Food and Nutrition Board

KATHERINE R. KANE, Senior Program Assistant (until March 2024)

SAMANTHA SISANACHANDENG, Senior Program Assistant (as of April 2024)

BOARD ON AGRICULTURE AND NATURAL RESOURCES

JILL J. MCCLUSKEY (Chair), Washington State University, Pullman

AMY W. ANDO, University of Illinois, Urbana-Champaign

ARISTOS ARISTIDOU,¹ Biomason, Inc., Durham

BRUNO BASSO, Michigan State University, East Lansing

BERNADETTE M. DUNHAM, George Washington University, Washington, DC

JESSICA E. HALOFSKY, U.S. Department of Agriculture–Pacific Northwest Research Station, Portland

ERMIAS KEBREAB, University of California, Davis

MARTY D. MATLOCK, University of Arkansas, Fayetteville

JOHN P. MCNAMARA, Washington State University, Pullman

NAIMA MOUSTAID-MOUSSA, Texas Tech University, Lubbock

V. ALARIC SAMPLE, George Mason University, Fairfax

ROGER E. WYSE, Spruce Capital Partners, San Francisco

Staff

ROBERTA SCHOEN, Director

CAMILLA YANDOC ABLES, Senior Program Officer

MALIA BROWN, Program Assistant

CYNTHIA GETNER, Senior Finance Business Partner

KARA N. LANEY, Senior Program Officer

ALBARAA SARSOUR, Program Officer

SAMANTHA SISANACHANDENG, Senior Program Assistant

FOOD AND NUTRITION BOARD

SHIRIKI K. KUMANYIKA (Chair),¹ Drexel University School of Public Health, Philadelphia

JAMY D. ARD,¹ Wake Forest Baptist Medical Center, Winston-Salem

RODOLPHE BARRANGOU,^2,3 North Carolina State University, Raleigh

BRUCE Y. LEE, City University of New York Graduate School of Public Health and Health Policy, New York

MICHAEL C. LU, University of California, Berkeley

MARIAN L. NEUHOUSER, Fred Hutchinson Cancer Research Center, Seattle

ANGELA M. ODOMS-YOUNG, University of Illinois at Chicago

NICOLAAS P. PRONK, Health Partners, Inc., Waldorf

KATHLEEN M. RASMUSSEN, Cornell University, Ithaca

SYLVIA B. ROWE, SR Strategy, LLC, Washington DC

BARBARA O. SCHNEEMAN, University of California, Davis

ANNA MARIA SIEGA-RIZ, University of Massachusetts at Amherst

R. PAUL SINGH,³ University of California, Davis

Staff

ANN YAKTINE, Director

ELIZABETTE ANDRADE, Senior Program Officer

MELANIE ARTHUR, Research Assistant

HEATHER COOK, Senior Program Officer

KATHERINE DELANEY, Program Officer

CYPRESS LYNX, Associate Program Officer

JENNIFER MOUSER, Senior Program Assistant

AMANDA NGUYEN, Program Officer

MEREDITH PARR, Research Assistant

ANDI REISER, Senior Program Assistant

JENNIFER STEPHENSON, Research Associate

ALICE VOROSMARTI, Associate Program Officer

Reviewers

This Consensus Study Report was reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise. The purpose of this independent review is to provide candid and critical comments that will assist the National Academies of Sciences, Engineering, and Medicine in making each published report as sound as possible and to ensure that it meets the institutional standards for quality, objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process.

We thank the following individuals for their review of this report:

Although the reviewers listed above provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations of this report nor did they see the final draft before its release. The review of this report was overseen by JEFFERY L. DANGL (NAS), University of North Carolina, and RICHARD M. AMASINO (NAS), University of Wisconsin–Madison. They were responsible for making certain that an independent examination of this report was carried out in accordance with the standards of the National Academies and that all review comments were carefully considered. Responsibility for the final content rests entirely with the authoring committee and the National Academies.

Acknowledgments

This report would not have been possible without the contributions of many people. First, we thank the sponsor of this study—the U.S. Department of Agriculture’s National Institute of Food and Agriculture. Second, this consensus study report was greatly enhanced by discussions with speakers who generously gave of their time to make presentations to the committee. (The full participant list can be found in Appendix B.) We are thankful to them for providing timely and thought-provoking information during our public meetings.

The committee and staff are grateful for the support of the National Academies of Sciences, Engineering, and Medicine’s staff who contributed to producing this report. The committee and staff thank Lauren Everett, Radiah Rose-Crawford, and Eric Edkin in the Executive Office of the Division on Earth and Life Studies; Cynthia Getner in the Office of the Chief Financial Officer; Anne Marie Houppert and Rebecca Morgan in the National Academies Research Center; Nancy Huddleston, Reece Meyhoefer, and Sydney O’Shaughnessy in the Office of the Chief Communications Officer; Hannah Fuller in the Office of News and Public Information; and Tucker Nelson in the Office of Congressional and Government Affairs. We would also like to thank Samantha Sisanachandeng and Katherine Dhurandhar for getting the report over the finish line.

IN MEMORY OF DIANA H. WALL

The committee dedicates this report to Dr. Diana H. Wall, the chair of the report committee, who passed away on March 25, 2024. Diana was a tenacious scientist who shaped the modern field of soil biodiversity. Her research and publications on soil organisms, particularly on nematodes in Antarctica, clarified critical links between climate change and soil biodiversity. In addition to her groundbreaking science, Diana contributed her energy and expertise to National Academies committees for more than 35 years. She was a leader in the field of soil science and a delightful colleague. This report and each member of the committee benefited from her insights and curiosity.

Contents

SUMMARY

1 INTRODUCTION

The Committee and Its Charge

The Committee’s Process

Scope and Organization of the Report

References

2 THE CONNECTIVITY OF HEALTH

Soil and One Health

Soil Health

Human Health and Wellness

Microbiomes and One Health

References

3 THE IMPORTANCE OF SOIL HEALTH TO NATURE’S CONTRIBUTIONS TO PEOPLE

Which of Nature’s Contributions to People Are Derived from Soil?

Material Nature’s Contributions to People

Regulating Nature’s Contributions to People

Nonmaterial Nature’s Contributions to People

Trade-Offs Among Nature’s Contributions to People

Conclusions

References

4 IMPACTS OF AGRICULTURAL MANAGEMENT PRACTICES ON SOIL HEALTH

Indicators of Soil Health

Agricultural Management Practices

Conclusions

References

5 LINKAGES BETWEEN AGRICULTURAL MANAGEMENT PRACTICES AND FOOD COMPOSITION AND SAFETY

Linking Agricultural Management Practices to Nutrient Density

Effects of Food Processing on Nutrient Density

Linking Agricultural Management Practices to Food Safety

Consumer Food Choices

Conclusions

References

6 INTERACTIONS OF SOIL CHEMICAL CONTAMINANTS, SOIL HEALTH, AND HUMAN HEALTH

Human Exposure to Contaminants in Soil

Contaminant Case Studies

Conclusions

References

7 MICROBIOMES AND THE SOIL–HUMAN HEALTH CONTINUUM

Microbiome Features as Indicators of Health Status

Soils, Microbes, and Human Health

Conclusions

References

8 GOING FORWARD

Monitoring and Managing Data

From Wastes to Resources

Complexity and Collaboration

APPENDIX A

APPENDIX B

Boxes, Figures, and Tables

BOXES

S-1 Statement of Task

1-1 Statement of Task

2-1 Land Use Trends

2-2 Climate Change and Soil Health

2-3 Food as a Prerequisite for Health

2-4 Influence of the Environment on Human Health

3-1 Soil Bioprospecting within the Framework of the Nagoya Protocol

3-2 Resilience and Soil-Derived Nature’s Contributions to People

3-3 Soil Organic Matter

4-1 Terminology Characterizing Farming Systems

4-2 Urban Agriculture

4-3 Breeding for Soil Health

4-4 Livestock and Soil Health

5-1 Effects of Management Practices on Forage Quality

5-2 Agricultural Management Practices and Plant Bioactives

5-3 Impact of Food Processing on Nonpathogenic Microorganisms That May Be Transferred to the Human Microbiome

5-4 Food-Processing Waste as a Tool to Improve Soil Health

5-5 Soil-Borne Human Pathogens

5-6 Pathogen Reduction in Biosolids

5-7 Burden of Mycotoxins

5-8 The Expanding Role of the Food Industry in Connecting Soil and Human Health

6-1 Biochar as Decontamination Possibility

7-1 Human Microbiome Project

7-2 Machine Learning and Artificial Intelligence for the Microbiome

7-3 Viruses

FIGURES

1-1 Soil health, its connection to ecosystem services and human management and use, and its interaction with earth systems, food systems, and the microbiome

2-1 Major U.S. land uses, by percent of acres, 1949 to 2012

2-2 Optimal physical, chemical, and biological properties that promote healthy soils for cropping systems

2-3 Soil viruses, microorganisms, and meso- and macrofauna grouped by size

2-4 The various microbial processes affecting soil chemical and physical properties

2-5 A biopsychosocial model of health and illness

2-6 U.S. households with children by food security status of adults and children, 2022

2-7 Social determinants of health

2-8 Microbiome transfer between environments and modes of transfer

2-9 Soil as a microbial reservoir for plant, animal, and human microbiomes

2-10 General structure of the bacterial and fungal communities from various plant-associated niches

3-1 The multiple functions of soil

3-2 The nitrogen cycle

3-3 The carbon cycle

3-4 The water cycle

4-1 Frequency of soil health indicators from a review of 62 publications where biological indicators are in green, chemical indicators are in red, and physical indicators are in blue

4-2 Four broad approaches that are often highlighted to promote soil health as well as common management practices that can align with those goals

4-3 Percent of mulch till and no-till planted acreage for four crops

4-4 Percentage of acreage, by survey crop and for all crops combined, using a tillage practice for four consecutive years

4-5 The spatial distribution of U.S. irrigated farmland in acres, 2017

4-6 The change in spatial distribution of U.S. irrigated farmland in acres, 1997 to 2017

4-7 Irrigated acres as a share of total acres harvested by crop in 2017

4-8 U.S. consumption of plant nutrients, 1960–2015

4-9 Potential functions microbial inoculants could enhance or provide in soils if the soil function is currently lacking or is limited by low abundance or activity of the inoculated organisms

4-10 Decision tree to assess whether microbial inoculations are likely to solicit crop response

5-1 Influence of soil health on aflatoxin accumulation in crops

6-1 Impacts of soil contaminants on key soil functions

6-2 The route of entrance and fate of contaminants in soils, and nine major soil processes determining the fate of soil contaminants

6-3 Transformation processes affecting the fate of pesticides and their degradation products in the environment

6-4 An example of contaminant source, fate, transport, and exposure setting

6-5 The source, movement, and fate of microplastics in the environment

6-6 A schematic diagram of microplastic interaction with plant–soil systems

6-7 A flow diagram illustrating the potential human health effects of microplastics

6-8 A diagram illustrating the sources of PFAS and pathways for their release into the water cycle and the environment

6-9 Elements of a remediation strategy for PFAS

7-1 Discussions of specific microorganisms or microbial processes that relate to human health in other chapters of the report

7-2 Organization of Chapter 7

7-3 A schematic illustrating the information gained from each -omic technology and how their integration is essential to fully understanding the phenome

7-4 Essential microbial exposures and nonessential or detrimental exposures

7-5 A schematic of known and proposed interactions between diet and cardiometabolic risk illustrates the known risk-reducing properties of vegetarian and Mediterranean diets on cardiometabolic diseases and the proposed interactions between the vegetarian and Mediterranean diets with the gut microbiome and gut-derived metabolites that can reduce cardiovascular disease risk

TABLES

S-1 Recommendations to Advance Understanding of Linkages Between Soil Microorganisms and Human Health

S-2 Recommendations to Advance Understanding of Agricultural Management Practices That Enhance Benefits to and Reduce Adverse Effects on Human Health

S-3 Recommendations to Advance Understanding of the Linkages Between Agricultural Management Practices and the Nutritive Value of Food

S-4 Recommendations to Improve Soil Health

2-1 Examples of Measurable Characteristics of Healthy Soils and Healthy Humans

3-1 Three Main Categories of Soil-Derived Nature’s Contributions to People (NCPs)

3-2 Examples of Marketed Compounds Originating from Soil Microbial-Derived Natural Products

6-1 Bioavailability and Strength of Adsorption of Select Contaminants to Soil Adsorbent Phases

6-2 Commonly Used Soil Amendments for Bioavailability-Based Remediation of Lead-Contaminated Soil

7-1 Microbiota-Based Content and the Use of This Information for Establishing Health in Human, Soil, and Plant Systems

Preface

Quotes capturing the importance of soil to our existence are not difficult to find. In fact, the U.S. Department of Agriculture has compiled a list on its website, with contributions ranging from Homer to the Indigo Girls. Perhaps not surprisingly, you will find a few of those quotes in this report. What most on the list have in common is the connectivity of the well-being of humanity to the health of soil.

Yet, soil, compared to other earth systems, is understudied. This neglect is partly because what is out of sight is out of mind, and the complexity of soil processes is definitely out of sight. That connects to another problem with soils: what is out of sight is often difficult to study.

However, with technological advances, seeing and sensing what goes on below the surface is becoming more feasible and, with each passing day, a little less expensive. These capabilities could not come soon enough to address challenges humanity faces in the 21st century: global warming, food security and malnutrition, and antibiotic resistance. In all these threats, soil has a role to play.

Furthermore, we can use our increasing knowledge of soil processes not just to address these challenges but to restore function and preserve biodiversity in the soils we have largely taken for granted as we have worked to feed the world’s growing population over the last century. We can also explore the complexity and connectivity of the microorganisms that live in soil, on plants, and in us and possibly unlock new opportunities to improve health in all three domains.

These are not small topics to tackle, and I want to thank my fellow committee members for their dedication to our task to explore linkages between soil health and human health. Writing this report required more than a year of service. Through numerous in-person meetings and Zoom calls and countless revisions, they stayed focused on their commitment, bringing their diverse expertise and working constructively in groups and as an entire team to address a broad statement of task. I learned a great deal from

Acronyms and Abbreviations