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An authoritative exploration of soil health management and land-use strategies in the Iberian Peninsula
In Soil Health and Sustainability in Spain and Portugal, a team of distinguished researchers delivers an authoritative overview and soil health assessment of the Iberian Peninsula focusing on agrosystems and forests. The book explores the potential effects of different management and land-use strategies.
The Iberian Peninsula, a famously diverse area of land — in terms of climate, landscape, and soil — faces unique and varied limitations on agricultural production and soil conservation. This book addresses these limitations and provides a vision of how newly developed and traditional soil management techniques can induce changes in soil health.
Readers will also find:
- Thorough comparisons of different approaches to soil health assessment in the Iberian Peninsula
- Comprehensive explorations of soil health evaluation in arid conditions and irrigated soils
- Practical discussions of the resilience of agrosystems developed to address climate change
- Treatments for forest and croplands soil health in Spain and Portugal
Perfect for soil and agricultural scientists, Soil Health and Sustainability in Spain and Portugal will also benefit anyone with an interest in sustainability issues in the Iberian Peninsula.
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Veröffentlichungsjahr: 2025
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Table of Contents
Cover
Table of Contents
Series Page
Title Page
Copyright Page
Soil Health Insights from Spain and Portugal
Preface
1 Soil Health in the Iberian Peninsula
Chapter Overview
Introduction
General Geophysical Characteristics and Land Uses
Historical Assessment
Case Studies in This Book
Agricultural Soils
Acknowledgments
References
2 Soil Health Evaluation for Permanent Crops Under Semiarid Mediterranean Conditions: Principles, Processes, Practices, and Policy Options
Chapter Overview
Soil Relevance and Global Threats
Soil Health, Sustainable Soil Management, and Ecological Intensification to Combat Global Threats: Desertification, Climate Change, and Biodiversity Loss
Soil Health and Sustainable Soil Management: Concept Evolution and Research Progress
Lessons Learned from a Case Study
Scientific Knowledge Gaps, Research Needs, and Policy Recommendations
Acknowledgments
References
3 Soil Health and Agricultural Production of Diversified Crops in Southeastern Spain
Chapter Overview
Introduction
Material and Methods
Results
Discussion
Acknowledgments
References
4 Urban Soil Health: A Case Study from Northwestern Spain
Chapter Overview
Introduction
Study Area
Results and Discussion
Conclusion
References
5 Management Practices and Land Use to Enhance Soil Health of Highly Weathered Degraded Acid Soils in the Iberian Peninsula
Chapter Overview
Introduction
Soil Problems in the Rañas of the Southwestern Iberian Peninsula
Characteristics of the Study Area
Experimental Trials and Measurements
Effects of Land Use and Management on Chemical Properties
Effects of Land Use and Management on Soil Organic Carbon
Effects of Land Use and Management on Physical Properties
Effect of Management on Crop and Water‐Soil Relations
Management Effects on Crop Productivity
Effects of Management on Microbiological Properties
Impact on GHG Emissions
Conclusion
Acknowledgments
References
6 Can Irrigation Enhance Soil Health? Multi‐Scale Analysis of Its Effects on Agricultural Soils in Navarre, Spain
Chapter Overview
Introduction
Characterization of the Region of Navarre
Assessment of the Effect of Irrigation at the Experimental Field Scale
Regional Assessment of the Effect of Irrigation on Soil Health in the Region of Navarre
Conclusion
Acknowledgments
References
7 Applicability of Visual Assessment for Evaluating Soil Health in Managed Planted Forests in Northern Spain
Chapter Overview
Introduction
Materials and Methods
Results
Discussion
Conclusion
Acknowledgments
References
8 Soil Health After >25 Years of Sewage Sludge Application in Arable Crops in Northern Spain
Chapter Overview
Introduction
Materials and Methods
Statistical Analysis
Results
Discussion
Conclusions
Acknowledgments
References
9 Soil Health in Forest and Agroforestry Systems in Portugal
Chapter Overview
Introduction
Study Sites and Experiments
Concepts and Indicators
Soil Quality in Forestry and Agroforestry Systems
General Considerations and Perspectives
Acknowledgment
References
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Soil Health References.
Chapter 2
Table 2.1 Main Findings on Beneficial and Detrimental Agro‐environmental an...
Chapter 3
Table 3.1 Key Aspects of the Different Treatments in Each Case Study.
Table 3.2 Primers Used in This Study.
Table 3.3 PCR Cycling Conditions
Table 3.4 Absolute Values of the Studied Soil Physicochemical Properties in...
Table 3.5 Absolute Values of the Studied Soil Physicochemical Properties in...
Table 3.6 Absolute Values of the Studied Soil Physicochemical Properties in...
Table 3.7 Absolute Values of the Studied Soil Microbiological Properties in...
Table 3.8 Variation Rates (%) of the Studied Soil Physicochemical Propertie...
Table 3.9 Variation Rates (%) of the Studied Soil Physicochemical Propertie...
Table 3.10 Variation Rates (%) of the Studied Soil Physicochemical Properti...
Table 3.11 Variation Rates (%) of the Studied Soil Microbiological Properti...
Table 3.12 Variation Rates (%) and Data of Crop Production (kg/ha) in Almon...
Table 3.13 Matrix of PCA Obtained with Variation Rates (%) of Soil Physicoc...
Chapter 4
Table 4.1 Summary of Soil Properties Measured and Methods Used.
Table 4.2 Summary of Soil Properties (0–20 cm).
Chapter 5
Table 5.1 Soil Properties of a Representative Profile in the Study Area.
Table 5.2 Soil Measurements and Laboratory Methods.
Table 5.3 Content of Exchangeable Basic Cations and Aluminum in the Surface...
Table 5.4 Cumulative Emissions of N
2
O and CH
4
Fluxes Over the Periods of Ba...
Chapter 6
Table 6.1 Soil Determinations and Methods.
Table 6.2 Characteristics of the Groups Included.
Table 6.3 RUSLE
K
Factor (Soil Erosion Indicator), Biomass Production, Annu...
Chapter 7
Table 7.1 Site Characteristics of 10 Radiata Pine Stands and 2 Beech Stands...
Table 7.2 Soil Disturbance Categories Used in the Visual Assessment of Soil...
Table 7.3 Transect Length, Distance Between Monitoring Points and the Optim...
Table 7.4 Resistance to Penetration (RP), Soil Moisture (SM), Saturated Hyd...
Table 7.5 Resistance to Penetration (RP), Soil Moisture (SM), Saturated Hyd...
Table 7.6 Resistance to Penetration (RP), Soil Moisture (SM), Saturated Hyd...
Chapter 8
Table 8.1 Experimental Design for Fertilization With and Without SS at the ...
Table 8.2 Crop Rotation over the Years in the Arazuri LTE.
Table 8.3 Physicochemical Properties of the SS Used in This Study in 2018....
Table 8.4 Nitrogen Fertilizer Units (NFUs) Provided by the Study Doses Acco...
Table 8.5 Soil Physical and Chemical Properties (0–30 cm).
Table 8.6 Results for Bulk Density (BD), Soil Water Retention (SWR) at Diff...
Table 8.7 Results for Penetration Resistance (PR), Pore Diameter (Ø), Water...
Table 8.8 Results for Total Nitrogen (TN), Available Phosphorus (Olsen P), ...
Table 8.9 Results for Total Carbonates and Available Trace Metals (Mn, Zn, ...
Table 8.10 Results for Total Organic Carbon (TOC), Organic Carbon in Partic...
Chapter 9
Table 9.1 Location, Climate Characteristics, Landscape, and Soil of the Dif...
Table 9.2 Indicators Used Among Experiments and Study Areas for the Assessm...
Table 9.3 Bulk density (BD), Aeration Porosity (AP), Water Infiltration Rat...
Table 9.4 Bulk Density (BD), Aggregation Coefficient (AC), Mean Weight Diam...
Table 9.5 Bulk Density (BD), Aggregation Coefficient (AC), Mean Weight Diam...
Table 9.6 Indexes of Diversity of Shannon (DIV), Equitability of Pielou (EQ...
Table 9.7 Carbon in Particulate Organic Matter (C
POM
) and Extractable by Ho...
Table 9.8 Extractable Phosphorus (Ext P), Total Nitrogen (TN), Microbial Ni...
Table 9.9 Bulk Density (BD), pH Values, and Concentrations of Organic Carbo...
Table 9.10 Initial Content of Microbial Carbon and Nitrogen (C
mic
, N
mic
), M...
Table 9.11 Concentrations of Soil Organic Carbon (OC) and Total Nitrogen (T...
Table 9.12 Bulk Density (BD), Aeration Porosity (AP), Resistance to Penetra...
Table 9.13 Concentration of Soil Organic Carbon (Org C) and the Particulate...
Table 9.14 Concentrations of Organic Carbon (Org C), Total Nitrogen (TN), C...
Table 9.15 Amount of Nitrogen, Cumulative Mineral Nitrogen (NH
4
+
‐N + NO
3
‐N)...
Table 9.16 Production of Nuts, Forage, Total Sporocarps (TS), and Commercia...
Table 9.17 Nutrient Foliar Concentration in
Quercus suber
(QS) and
Quercus
...
List of Illustrations
Chapter 1
Figure 1.1 Major systems and river basins (left) and main geologic domains (...
Figure 1.2 Lithologic domains in the Iberian Peninsula. Own elaboration from...
Figure 1.3 Distribution of average annual rainfall (top), and temperature (c...
Figure 1.4 Distribution of soil groups of the World Reference Base in the Ib...
Figure 1.5 Distribution of Cambisols, Leptosols, Regosols, Luvisols, and Pod...
Figure 1.6 Land use in the Iberian Peninsula (top), and distribution of land...
Figure 1.7 Evolution of scientific production on soil quality (red line, pri...
Figure 1.8 Topic categories considered within soil quality publications.
Figure 1.9 Wordcloud with the 50 most frequent terms within soil quality pub...
Figure 1.10 Wordcloud with the 50 most frequent terms within soil health pub...
Chapter 2
Figure 2.1 Creating Positive Soil Carbon, Nutrient, and Water Balances.The a...
Figure 2.2 Synergies and Trade‐offs Resulting from the Adoption of Sustainab...
Figure 2.3 Impact of Agricultural Intensification on Soil Functional Biodive...
Figure 2.4 Climate and Agro‐environmental Policy Framework to Cope with Emer...
Figure 2.5 Soil Health Objectives According to the EU Mission “A Soil Deal f...
Figure 2.6 Aspect of different soil management practices and vegetation cove...
Chapter 3
Figure 3.1 Almond monocrop (left) and almond diversified with thyme (right) ...
Figure 3.2 Mandarin monocrop (left) and mandarin diversified with fava bean ...
Figure 3.3 Melon monocrop (left) and melon‐cowpea mixed intercropping (right...
Figure 3.4 PCA factor scores of variations in soil physicochemical and micro...
Chapter 4
Figure 4.1 Location of Study Area, Sampling Points, and Lithology (Profile O...
Chapter 5
Figure 5.1 Location in the Iberian Peninsula and satellite image of the stud...
Figure 5.2 Cork oak and olive groves are the most contrasting land uses in t...
Figure 5.3 Vertical profiles of pH, calcium, and aluminum to a depth of 50 c...
Figure 5.4 Concentration of soil organic carbon (g/kg) in the first 10 cm of...
Figure 5.5 Evolution of soil organic carbon (SOC) and particulate organic ca...
Figure 5.6 Soil organic carbon (SOC) and particulate organic carbon (POC) in...
Figure 5.7 Gravimetric soil moisture and degree of water saturation as affec...
Figure 5.8 Forage biomass production in relation to precipitation: (a) annua...
Figure 5.9 Structural equation model of the hypothesized relationships betwe...
Chapter 6
Figure 6.1 Agricultural land use in the region of Navarre (left) and Köppen ...
Figure 6.2 Bulk soil organic carbon (SOC) stocks (Mg ha
−1
) per crop‐ir...
Figure 6.3 Particulate organic carbon (POC) stocks (Mg ha
−1
) per crop‐...
Figure 6.4 Flow chart of the two‐parallel pools model.
IF
represents the pro...
Figure 6.5 Values of MRT
1
(a), MRT
2
(b), the proportion from crop residues i...
Figure 6.6 Homogeneous zones and network of groups of commercial agricultura...
Figure 6.7 Response ratio (RR) of soil organic carbon (SOC) stocks (0–20 cm)...
Figure 6.8 Response ratio (RR) of soil organic carbon (SOC) stocks (0–20 cm)...
Figure 6.9 Response ratio (RR) of bulk density for irrigation transformation...
Figure 6.10 Response ratio (RR) of bulk density for irrigation intensity eva...
Figure 6.11 Response ratio (RR) of available water holding capacity for irri...
Figure 6.12 Response ratio (RR) of available water holding capacity for irri...
Figure 6.13 Annual GHG emissions associated to each system considered in the...
Figure 6.14 Microbial biomass carbon (MBC) measured in 0–15 cm and 15–30 cm ...
Figure 6.15 Number of substrates used by the soil microbial community (NSU) ...
Chapter 7
Figure 7.1 Illustration of a random transect with a randomly located a start...
Figure 7.2 Percentage of stand occupied by each soil disturbance in manually...
Chapter 8
Figure 8.1 Arazuri Wastewater Treatment Plant and Arazuri long‐term experime...
Figure 8.2 Sampling in Arazuri experimental field for disturbed samples (top...
Figure 8.3 Thin section (SS‐fertilized treatment): (a) under plain polarized...
Figure 8.4 Proportion of pores of different equivalent diameter, as calculat...
Figure 8.5 Earthworms abundance (bars, left axis, capital letters) and avera...
Figure 8.6 Wheat yield for the treatments with sewage sludge (SS) at differe...
Chapter 9
Figure 9.1 Distribution of eucalypt plantations (a), evergreen oak woodlands...
Figure 9.2 Bulk density (BD) and organic carbon (Org C) concentration with s...
Figure 9.3 Soil resistance to penetration as affected by soil ripping and ha...
Figure 9.4 Variation of soil parameters with the distance to the tree trunk ...
Figure 9.5 Bulk density (BD), and organic C (Org C) concentrations in improv...
Figure 9.6 Cork oak stand with natural shrub understory (NU) and with a 5‐ye...
Figure 9.7 Bulk density (BD), and volume of air‐filled porosity (AFP) and wa...
Figure 9.8 Proportion of classes of soil saturated hydraulic conductivity, m...
Figure 9.9 Chestnut groves subjected to conventional tillage (left) and no t...
Figure 9.10 Concentration of organic carbon, according to soil depth (cm), i...
Figure 9.11 Effects of harvesting residue management (and ripping) on timber...
Guide
Cover Page
Table of Contents
Series Page
Title Page
Copyright Page
Soil Health Insights from Spain and Portugal
Preface
Begin Reading
WILEY END USER LICENSE AGREEMENT
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SERIES EDITORDouglas L. Karlen
EDITORSIñigo Virto and Rodrigo Antón
CONTRIBUTORSMaria AlmagroInstitute of Agricultural Research and Training, Fishing, Food and Organic Farming of Andalusia (IFAPA), Camino de Purchil s/n, Granada, SpainRodrigo AntónÁrea Edafología y Química Agrícola, Departamento de Ciencias, IS‐ FOOD, Universidad Pública de Navarra (UPNA), 31006, Pamplona, SpainAnder Arias‐GonzálezNEIKER ‐ Basque Institute for Agricultural Research and Development, Department of Forest Sciences, 48160, Derio, SpainCarolina Boix‐FayosSoil and Water Conservation Research Group, Centro de Edafología y Biología Aplicada del Segura, CEBAS‐CSIC, Campus Universitario de Espinardo Murcia, SpainJessica CuarteroSwiss Federal Research Institute Wsl, Birmensdorf, SwitzerlandIsabel S. de SotoÁrea Edafología y Química Agrícola, Departamento de Ciencias, IS‐ FOOD, Universidad Pública de Navarra (UPNA), 31006, Pamplona, SpainDelphine DerrienUMR Sol, Agro et hydrosystème, Spatialisation (SAS), INRAE‐ Rennes, 35042, Rennes, FranceElvira Díaz‐PereiraSoil and Water Conservation Department, CEBAS‐CSIC (Spanish Research Council), Campus de Espinardo, Murcia, SpainAlberto EnriqueÁrea Edafología y Química Agrícola, Departamento de Ciencias, IS‐ FOOD, Universidad Pública de Navarra (UPNA), 31006, Pamplona, SpainRafael EspejoDepartment of Agrarian Production, Universidad Politécnica de Madrid. Avda. Puerta de Hierro 2, 28040, Madrid, SpainAntónio FabiãoForestry Research Centre, Instituto Superior de Agronomia, Lisboa, PortugalJuan A. FernándezDepartment of Agricultural Engineering, Universidad Politécnica de Cartagena, Cartagena, SpainInstituto de Biotecnología Vegetal (IBV), Campus Muralla del Mar, Edificio I+D+I, Universidad Politécnica de Cartagena, Cartagena, SpainNahia Gartzia‐BengoetxeaNEIKER ‐ Basque Institute for Agricultural Research and Development, Department of Forest Sciences, 48160, Derio, SpainNoelia Garcia‐FrancoChair of Soil Science, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, GermanyChiquinquirá HontoriaDepartment of Agrarian Production, Universidad Politécnica de Madrid. Avda. Puerta de Hierro 2, 28040, Madrid, SpainCentro de Estudios e Investigación para la Gestión de Riesgos Agrarios y Medioambientales, CEIGRAM, Universidad Politécnica de Madrid, Senda del Rey, 13, 28040, Madrid, SpainMiguel ItarteÁrea Edafología y Química Agrícola, Departamento de Ciencias, IS‐ FOOD, Universidad Pública de Navarra (UPNA), 31006, Pamplona, SpainManuel MadeiraForestry Research Centre, Instituto Superior de Agronomia, Lisboa, PortugalIgnacio Mariscal‐SanchoDepartment of Agrarian Production, Universidad Politécnica de Madrid. Avda. Puerta de Hierro 2, 28040, Madrid, SpainCentro de Estudios e Investigación para la Gestión de Riesgos Agrarios y Medioambientales, CEIGRAM, Universidad Politécnica de Madrid, Senda del Rey, 13, 28040, Madrid, SpainInazio Martínez de AranoEuropean Forest Institute, Bioeconomy Program, Bioregions Facility, Joensuu, North‐Karelia, FinlandMaría Martínez‐MenaSoil and Water Conservation Department, CEBAS‐CSIC (Spanish Research Council), Campus de Espinardo, Murcia, SpainAfonso MartinsUniversidade de Trás‐ os‐ Montes e Alto Douro (UTAD), Apartado 1013, Vila Real, PortugalLuis OrcarayInstituto Navarro de Infraestructura y Tecnologías Agroalimentarias (INTIA), Villava, SpainOnurcan ÖzbolatDepartment of Agricultural Engineering, Universidad Politécnica de Cartagena, Cartagena, SpainInstituto de Biotecnología Vegetal (IBV), Campus Muralla del Mar, Edificio I+D+I, Universidad Politécnica de Cartagena, Cartagena, SpainJosé Antonio PascualSoil and Water Conservation Department, CEBAS‐CSIC (Spanish Research Council), Campus de Espinardo, Murcia, SpainRemigio Paradelo NúñezCRETUS, Departamento de Edafoloxía e Química Agrícola, Universidade de Santiago de Compostela, Facultade de Farmacia, Santiago de Compostela, SpainFernando PeregrinaDepartment of Agrarian Production, Universidad Politécnica de Madrid. Avda. Puerta de Hierro 2, 28040, Madrid, SpainCentro de Estudios e Investigación para la Gestión de Riesgos Agrarios y Medioambientales, CEIGRAM, Universidad Politécnica de Madrid, Senda del Rey, 13, 28040, Madrid, SpainFernando RaimundoUniversidade de Trás‐ os‐ Montes e Alto Douro (UTAD), Apartado 1013, Vila Real, PortugalAna Raquel Rodriguesinigo.virtoAdega Cooperativa de Dois Portos, D.R.L., Dois Portos‐ Torres Vedras, PortugalMargarita RosSoil and Water Conservation Department, CEBAS‐CSIC (Spanish Research Council), Campus de Espinardo, Murcia, SpainVirginia Sánchez‐NavarroDepartment of Agricultural Engineering, Universidad Politécnica de Cartagena, Cartagena, SpainAna Simoes‐MotaÁrea Edafología y Química Agrícola, Departamento de Ciencias, IS‐ FOOD, Universidad Pública de Navarra (UPNA), 31006, Pamplona, SpainPaula SoaresForestry Research Centre, Instituto Superior de Agronomia, Lisboa, PortugalHenar UrmenetaDepartamento Estadística, Informática y Matemáticas, Universidad Pública de Navarra, 31006, Pamplona, Navarra, SpainIñigo VirtoÁrea Edafología y Química Agrícola, Departamento de Ciencias, IS‐ FOOD, Universidad Pública de Navarra (UPNA), 31006, Pamplona, SpainArmelle ZaragüetaÁrea Edafología y Química Agrícola, Departamento de Ciencias, IS‐ FOOD, Universidad Pública de Navarra (UPNA), 31006, Pamplona, SpainRaúl ZornozaDepartment of Agricultural Engineering, Universidad Politécnica de Cartagena, Cartagena, SpainInstituto de Biotecnología Vegetal (IBV), Campus Muralla del Mar, Edificio I+D+I, Universidad Politécnica de Cartagena, Cartagena, Spain
EDITORIAL CORRESPONDENCESoil Science Society of America5585 Guilford Road, Madison, WI 53711‐58011, USA
SOCIETY PRESIDENTSPeter M. Kyveryga (ASA)Mark E. Sorrells (CSSA)Samira Daroub (SSSA)
SOCIETY EDITORS IN CHIEFDavid E. Clay (ASA)Bingru Huang (CSSA)Markus Flury (SSSA)
BOOK AND MULTIMEDIA PUBLISH COMMITTEEGirisha K. Ganjegunte (Chair)Sangamesh V. AngadiFugen DouShuyu LiuSara Eve Vero
BOOKS STAFFMatt Wascavage (Director of PublicationsRichard J. Easby (Program Manager, ContentStrategy)Julia Barrett (Copyeditor)
Soil Health Series: Volume 5 Soil Health and Sustainability in Spain and Portugal
Edited by
Iñigo Virto and Rodrigo Antón
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Cover Design: WileyCover Image: Courtesy of Iñigo Virto, Courtesy of Ignacio Mariscal‐Sancho, Courtesy of Fernando Raimundo
Soil Health Insights from Spain and Portugal
Douglas L. Karlen, Soil Health Series Editor
Soil Health and Sustainability in Spain and Portugal is the fifth volume in the Soil Health Series being published by Wiley and the Soil Science Society of America (SSSA). Volumes one and two provide background and general methods for assessing soil biological, chemical, and physical properties and processes affecting soil health, while volumes three and four explore those factors, indicators, and management practices affecting soil health in Brazil and India, respectively. This volume, edited by Professor Iñigo Virto and Professor Rodrigo Antón draws upon their research experience in Spain, France and the U.S. on soil health, the soil C cycle, and its response to management to further our global evaluations of the concept. Collaborating with scientists from Spain, Portugal, and other countries, this volume focuses on soil health and sustainability throughout the Iberian Peninsula.
For those not familiar with this geographic area, the Iberian Peninsula, encompasses 583,254 km2 and is the second‐largest European peninsula by area after the Scandinavian Peninsula. It is the westernmost of the three major southern European peninsulas and of the larger Eurasian landmass and has a population of roughly 53 million. There are three dominant climate types (Mediterranean, oceanic, and highland alpine) with a topography that is very contrasting and has uneven relief.1
Chapter 1 identifies the most relevant soil health issues and provides a general overview of the natural conditions of the Iberian Peninsula. The diversity and distribution of major soil types, climates, and land uses are examined to evaluate inter‐relationships between agricultural management and soil health. Chapter 2 examines different sustainable agricultural management practices for soil carbon sequestration and stabilization, as an indicator of soil health for permanent crops under semiarid conditions. Green manuring or retaining pruning residues are shown to be effective for coping with climate change, but there are no a tailored‐made solutions for these semiarid regions. Chapter 3 examines crop diversity in Southeastern Spain with three cash crops (rainfed almonds, irrigated mandarins, and vegetables) by quantifying the variation in different soil physical, chemical and biological indicators of soil health. The results show that crop diversity enhances soil health through the incorporation of plant biomass which creates wider diversity in soil microorganisms with multiple functions.
Chapters 4 and 8 examine soil health in an urban environment and after 25 years of sewage sludge application in Northern Spain. The urban study was done in Santiago de Compostela (Spain) and shows that maintaining and enhancing soil health in those environments can be quite challenging because many soils have been disturbed by anthropic activities and contamination. A study established in 1992 close to Pamplona (Spain) was used to evaluate the impact of sewage sludge recycling, one of the circular economy and European Green Deal goals. The study quantifies several soil physical, chemical and biological indicators, as well as their relation to crop yield and quality in a four‐year rotation.
Chapter 5 and 6 examine soil health of highly weathered degraded acid soil and the potential to use irrigation to enhance soil health, respectively. Acid soils are primarily located in the western third of the Iberian Peninsula, on the siliceous domain of the Hesperian massif. They are poor soils that can function to support arboreal plants or arbustive vegetation, which consists of woody plants that are smaller than trees but larger than herbaceous plants but are very vulnerable when cultivated. Chapter 5 examines the long‐term effects of integrated farming treatments on a selection of chemical, physical and biological soil properties, measured at different depths, and their relationships with crop development and greenhouse emissions. Chapter 6 is important, since due to climate uncertainty in many areas, including the Mediterranean basin, up to 80% of agricultural production comes from irrigated land. However, the use of irrigation can also increase the environmental footprint of agriculture, which opens questions on the sustainability of irrigation in some areas. This chapter examines soil health during a transition from dryland agriculture to long‐term irrigation for different soil and climate conditions within the Iberian Peninsula.
Finally, Chapters 7 and 9 focus on planted and managed forests in Northern Spain and forest and agroforestry systems in Portugal, respectively. In N Spain and Portugal, Pinus radiata and Pinus pinaster plantations occupy more than 290,000 ha and 2 million ha, respectively, with rotation lengths between 35 and 40 years. Conventional site preparation consists of the partial removal of logging residues followed by down‐slope ripping or blading which pushes logging residues and the humus layer away from the site. This depletes nutrients, increases soil loss, and degrades soil physical properties. Visual assessment is used to evaluate those problems from a soil health perspective.
Overall, Iñigo, Anton and their colleagues have compiled an excellent volume that addresses soil health and sustainability throughout the Iberian Peninsula. Thank you for your excellent contribution to our Soil Health Series.
Note
1
The Iberian Peninsula.
https://en.wikipedia.org/wiki/Iberian_Peninsula
Preface
This volume in the Soil Health series was written at the invitation of Dr. Douglas L. Karlen and the Soil Science Society of America, and is the fifth in the series, after the first two edited by Dr. Karlen and his collaborators on general perspectives and methodologies.
The objective of this series is to provide a comprehensive overview of experience‐based knowledge on soil health assessment under different soil, climate and management conditions globally. Under the umbrella of the first two volumes, the aim is to provide an approach focused on studies developed in different areas of the world, where systematized soil health studies have been conducted. In this case, a selection of case studies in the Iberian Peninsula is offered, which try to be representative of the diversity of natural conditions of our territory, and of the majority uses of the soil that occur in it. Thus, the book includes works of soil health assessment in agricultural (rainfed and irrigated) land, forest and urban soils, in a gradient of climates that corresponds to the most representative conditions of the Peninsula.
Corresponding to this heterogeneity, the approaches to the study of soil health in the different chapters are also diverse. Thus, there are chapters focused on the study of a few selected indicators, and others that use wider ranges, and even a chapter focused on the visual assessment of soil condition in forest management.
This diversity of approaches corresponds to that described in the first book of the series regarding the evolution of soil quality assessment, and even of the concept itself. As described in the first chapter, the definition of Soil Health, and of the methods for its assessment, has changed in recent decades from an approach focused mainly on the productivity of agricultural and forest soils, to an approach that considers soil functions within the (agro)ecosystem, as well as its role in the provision of ecosystem services that contribute to the maintenance of the environment and human well‐being. An idea that actually develops in contemporary times, and attempts to systematize, the concern for soil quality that has accompanied humankind since its origin, and in particular since the establishment of sedentary communities whose survival depends on the conservation of natural resources.
This book has also been written in a context of growing awareness on the part of society as a whole, and of the Administration, of the importance of the soil resource for our well‐being. In particular, the European Union has developed several initiatives in recent years with the aim of increasing knowledge and regulating the health of Europe's soils (with initiatives such as the European Soil Protection Strategy, the EJP‐Soil Joint European Program, the Soil Mission, the C Agriculture Regulation, and above all, the proposed Soil Monitoring and Resilience Directive). In addition, both environmental and agricultural policies include in the Union different mechanisms that try to protect more or less indirectly the health of Europe's soils.
Undoubtedly, all these initiatives have been and are the subject of debate among policymakers, stakeholders, and even within the scientific community itself, so we can speak of a moment of special intensity in our continent in the debate on strategies and tools for soil health assessment, not only among professionals, but even in the regulations themselves. This book is thus more a “state of the art” than a closed work, which attempts to provide quantitative and science‐based information on the particular case of some soils of continental Spain and Portugal. For this reason, priority has been given to the search for long‐term studies and/or comprehensive assessments of the agricultural or forestry systems considered.
The long trajectory of many agricultural and forestry research and consultancy institutions in our territory would undoubtedly allow the development of several more volumes on this subject. Following the example of the first volume, in this book we have decided to start somewhere, and open to the public some representative cases, instead of embarking on the impossible task of trying to cover all possible situations and approaches.
Iñigo Virto & Rodrigo Antón
1Soil Health in the Iberian Peninsula
Iñigo Virto, Rodrigo Antón, Miguel Itarte, and Alberto Enrique
Chapter Overview
This chapter summarizes the most relevant geographical and physical characteristics of the Iberian Peninsula including its soils and land uses. It also introduces the general context in which the case studies described in the following chapters have been developed, and their relevance to soil health.
The chapter also includes an overview of soil health studies in the Peninsula in recent years, and the changes occurred in the topics of interest within these studies.
Finally, the chapter offers an overview of the information explained in the book chapters, grouped in relation to the land use they describe (agriculture, forest and urban soils).
Introduction
Soil health has become a unifying concept, tool, and goal for all kinds of soil‐related users, stakeholders, and decision‐makers in the past several decades (Karlen et al., 2021a, 2021b). In this book, we aimed to explore and present long‐term experiences dealing with different angles of soil health assessment and monitoring in the Iberian Peninsula, home to mainland Spain and Portugal. In this chapter, we introduce first the geophysical and land use context in this corner of Europe, revise the evolution of scientific production related to the topic, and summarize the contributions developed in the book's other eight chapters.
This work has been carried out in a fast‐changing context, both in terms of changes affecting soils, and in terms of the increase in general awareness and regulatory proposals about the protection of soils in the European Union. Indeed, soil health assessment is becoming paramount for understanding the response of soils to the so‐called contemporary “global change” due to biophysical planetary‐scale changes (e.g., atmospheric circulation and climate, biogeochemical cycles, the hydrological cycle, biodiversity) and changes in the human population, economy, use of resources, land use and cover, urbanization, and other human‐related activities. Owing to the key role of soils in terrestrial ecosystems and as the basis of agriculture, and thus the changes in use associated with primary production, soils appear at the center of global change, both in relation to its causes and its effects. This position implies that these changes directly affect the functioning of soils, and require new evaluation systems to assess soils as a resource, determine their responses to changes, and identify possible mitigation and adaptation strategies.
The increase in soil heath studies responds to this need and to the evidence that the role of soils in the face of global change must be approached from a global and holistic perspective. So far, the most widespread trend has been to evaluate the effect of specific soil management measures in isolation. This reductionist approach is common in scientific research and useful in local studies, but it sometimes has limited practical relevance to the wider farming and soil‐using community. For instance, the limitation of these approaches becomes clear in the case of agrarian systems, which are based on an interrelated and interdependent complex of options and measures that can only be slightly modified or not modified at all without affecting each other (Faber et al., 2022).
In fact, the basis for the development of concepts linked to soil quality or soil health is that the relationship between soil functioning and the services that soils provide is not univocal (different functions can provide the same service), and vice versa (the same service can depend on several functions), so establishing simple relationships is not easy or, in many cases, adequate. Thus, the definition of the concept of “soil quality” has varied from its first formal conceptions in the 1990s, based specifically on the condition of agricultural soils for production, towards a broader conception, which emphasizes sustainable management of the land and provides a holistic approach (Karlen et al., 2003). Indeed, throughout the history of soil science, concepts such as “soil productivity” (already cited in 1910), “soil conservation,” “soil security,” or “soil resilience” have been developed and have contributed to increase our awareness of the need to understand and protect the complexity of soil functioning beyond the study of a few or several isolated properties. These new concepts have emerged within the soil science community through multiple actions, such as reflection on the social, cultural, and/or political needs that exist outside this community, or by being progressive and relevant to new emerging interests such as global health or security (Mizuta et al., 2021).
In a recent attempt to compile the different approaches defined in the last years, the Intergovernmental Technical Panel on Soils (ITPS) of the Global Soil Alliance, led by the Food and Agriculture Organization of the United Nations, released a summary definition of soil health: “the capacity of the soil to sustain the productivity, diversity and environmental services of terrestrial ecosystems” (ITPS, 2021). This definition fits the core concept defined by Janzen et al. (2021), who concluded that the multiple definitions of this concept have at least three things in common. First, soil health has at its core the notion of functionality, that is, the ability of a soil to perform its vital functions normally. Second, the soil is considered as a living and dynamic system, with a torrent of connected and intertwined processes. Third, an essential element of the definition of soil health is sustainability or resilience, which acknowledges that a healthy soil maintains the functioning of the ecosystem over time.
However, the term soil health continues to appear to some as a theoretical and complex idea, essentially a “popular metaphor” (Janzen et al., 2021). A translation from metaphors into concrete facts and data, possibly applicable to quantitative assessment of soil health relevant for policy‐making and to regulations to rule this assessment, is needed to move from the emotional sphere to a political one (Panagos et al., 2022). In this context, the European Union is taking steps towards a concrete formulation for the protection of European soils. The European Commission has thus been preparing a Soil Health Law since 2020. This legal framework will contribute to (a) achieving the objectives of the European Soil Strategy 2030, with the aim of granting soils the same level of protection as water and air, and (b) radically improving the condition of soils to better provide the services that we depend on.
In compliance with this strategy, the European Union Soil Mission proposes that by 2030 at least 75% of the soils of each EU member state will be healthy or will show significant improvement towards compliance of the accepted thresholds of the indicators selected to support ecosystem services. This objective corresponds to an increase in healthy soils with respect to a reference baseline established by each member state. The determination of this reference must be made based on specific indicators. The indicators proposed by the EU Mission for Soil Health (A Soil Deal for Europe, European Commission, 2023) cover measurable physical, chemical, and biological soil properties and landscape parameters. At the same time, measurements will have to follow agreed protocols and thresholds that consider the variability of soil types, land use, and climate, with reference points defined by the member states themselves.
In this framework, consensus exists that the assessment of soil health needs to be done in the context of specific geographic, biophysical, and management conditions (Costantini et al., 2020). The Iberian Peninsula, because of its geographical location, physical characteristics, and long history of land use and land use changes, is home to a great diversity of landscapes, including many based on different uses of soils. A recent compilation of land of soil degradation pathways in Europe (Prăvălie et al., 2024) has shown that the peninsula is also one of the most threatened territories in Europe in this respect, with many areas included as those affected by three or more soil degradation problems. In particular, soil loss by water and wind erosion, soil compaction, nutrient imbalances, or acidification can be identified in different areas. Groundwater decay and aridity at critical levels in most of the southern half of the peninsula are additional relevant threats to soil functioning.
This book therefore presents some of the most representative situations in the peninsula in this respect and highlights the approaches used to assess soil health in each.
General Geophysical Characteristics and Land Uses
The Iberian Peninsula, considered in this chapter as the joint surface of continental Spain and Portugal, is located at the southwestern limit of the European continent, and extends over 582,400 km2. The peninsula displays extensive landscape and biological diversity owing to its geographical position and its geological, geomorphological, and bioclimatic characteristics. These characteristics also result in a great soil diversity.
From the geological and geomorphological point of view, as described by Maestro et al. (2013), the complex geological history of Iberia reflects its location between the African and European plates and is recorded by rocks ranging in age from Precambrian to Quaternary within a complex and diverse geological setting (Figure 1.1). The peninsula hosts several mountain ranges exceeding 2,000–2,500 m (Cantabrian Mountains, northwestern ranges, Central Range, and Iberian Range) and two ranges with peaks greater than 3,000 m (Pyrenees and Sierra Nevada in the Betic Range).
Despite this complexity, the peninsula can be divided into three main geologic domains based on lithological and hydrologic characteristics (Martín‐Serrano et al., 2005; Figure 1.1). These domains include (a) the so‐called Iberian or Hesperian Massif (western sector, including most of Portugal), (b) the mountain ranges of the Alpine orogeny (including the Pyrenees and other major chains of the same age) and other Mesozoic formations, and (c) the Cenozoic basins (including the sedimentation basins of the four major rivers: Tajo/Tejo, Duero/Douro, Ebro, and Guadalquivir). In some small areas, relatively recent volcanic complexes are also present, although they represent a minimal surface in the central, northeast, and northwest areas of continental Spain.
Figure 1.1 Major systems and river basins (left) and main geologic domains (right) in the Iberian Peninsula. Own elaboration from Martín‐Serrano et al. (2005) and IGME (2015).
The lithology of these domains can be also summarized in major lithological units (Gallardo, 2016; Figure 1.2). As such, siliceous metamorphic rocks (mainly slates, schists, and quartzites) and intrusive rocks (granites and similar) are the predominant materials in the Iberian Massif (Calvo de Anta et al., 2020). The Cenozoic basins are formed mostly of calcareous materials (limestones, dolostones, marls), and sedimentary rocks, which in most cases also include calcareous materials from their source areas. Major mountain chains display diverse lithologies related to their tectonic and orogeny processes (Vera et al., 2004). In the north, in the Pyrenees and Cantabrian Mountains (Figure 1.1), limestone and other calcareous materials alternate with older, metamorphized materials, especially in the axial zones of the Pyrenees, and pre‐Cenozoic materials. Other major ranges in the central and eastern areas (Iberian Mountains, Catalan Coastal Range, Figure 1.1) also contain significant calcareous massifs, and at some points, older metamorphic outcrops. In the south, the Betic Mountains are part of the Alpine ranges surrounding the Mediterranean (Mediterranean Alpine Orogen), with Triasic sedimentary materials in the North, and some metamorphic materials outcropping in the south.
The location and geography of the Iberian Peninsula also results in a multiplicity of climates. Because most wet fronts arrive from the Atlantic Ocean and flow from west to east, all northern and northwestern areas are, in general, rainier than the south and, especially than the east and southeast (Gallardo, 2016). Mountain chains in the north and in northern Portugal (Figure 1.1) also contribute to hinder the entry of these fronts to the inner part of the peninsula. As a result, there is a gradient in average annual rainfall from the northwest to the southeast (Figure 1.3). In terms of temperature, latitude, continentality, and altitude all play a role, resulting in a generally warmer southern half (with the highest temperatures recorded in the southeast and the Guadalquivir Basin; Figure 1.1), and milder temperatures in the northern half and mountain areas (Figure 1.3). In addition, the proximity to the ocean or sea makes coastal temperatures less variable throughout the year, whereas a larger contrast between the cold and warm seasons exists in the central area. Altitude also results in colder temperatures corresponding with the major ranges (Figures 1.1 and 1.3). This results in clearly different areas with contrasting annual water balance (moist or dry) and average temperatures (Figure 1.3).
Figure 1.2 Lithologic domains in the Iberian Peninsula. Own elaboration from IGME (2015).
These areas correspond to a large extent to those defined by the global Köppen climate classification (Figure 1.3). Most of the peninsula displays temperate (C‐type) climates, with differences in the amounts and distribution of precipitation. While most of the north is under moist C climates (Cf), the central and southern parts and a large area around the east coast display some type of summer drought (Cs). The temperature in the summer is lower in the northern half (Csb) than in the south and southeast (Csa). Csa climate corresponds to the classical Mediterranean climate (mild winters and dry, warm summers, and most rain falling in late winter or in spring or fall). In contrast, relevant areas in the eastern half (mostly corresponding to the Ebro depression and areas in the southeast) are arid enough to be defined as dry climates by Köppen (B‐type), in particular steppe‐like (Bs), differing owing to whether the annual temperature is milder (Bsk, <18 °C) or warmer (Bsh, >18 °C).
These differences in climate have consequences in land uses, types of natural vegetation, and especially in agriculture. While moist and fresh areas in the north and northwest have been traditionally devoted to forest and grasslands, plains and gentle‐slope areas in the central and eastern parts comprise most of the agricultural land. In many cases, irrigation is used on this land as a tool to increase yields and enable the productivity of crops.
In addition, the combination of these diverse soil forming factors results in a high diversity of soil types in Iberia. As depicted in Figure 1.4, major soil types comprise Cambisols of different types and Regosols and Leptosols, also with different qualifiers. Luvisols and Podzols are also present, mostly in the western half of the peninsula (Figure 1.5). Cambisols are relatively young soils, with little or no profile differentiation (either because of limited age, slow pedogenesis, or rejuvenation of the soil material), with at least an incipient subsurface soil formation and evidence of horizon differentiation based on changes in structure, color, clay, or carbonate content (IUSS Working Group WRB, 2022). These soils occur in a wide variety of environments around Europe and under many kinds of vegetation (Soil Atlas of Europe, 2005). The USDA Soil Taxonomy classifies most Cambisols as Inceptisols. Depending on their parent material, climate, and landscape positions, Cambisols can be differentiated in soils that have contrasting characteristics and behavior in terms of their response to management or potential use. In the Iberian Peninsula, two types are dominant according to the European Soil Data Center (ESDAC, ESDB v2.0, 2004, Figure 1.4). In the eastern part, corresponding to the areas with calcareous and sedimentary dominating lithologies, Calcaric Cambisols dominate (Figure 1.5). These are Cambisols having calcaric material between 20 and 50 cm from the surface, or between 20 cm and the bedrock, or a cemented layer (IUSS Working Group WRB, 2015). Other soils with calcaric or calcium‐rich features (such as Calcaric Leptosols and Regosols, and of course Calcisols) are also widespread in this part of the peninsula (Figure 1.5). In fact, in the Soil Atlas of Europe, these areas appear as occupied mostly by Calcisols (with substantial secondary accumulation of carbonates). These areas correspond to soils with a Mediterranean type of climate, including Calcixerepts and Haploxerepts according to the USDA Soil Taxonomy, which together cover more than 140,000 km2 in Spain (Gómez‐Miguel and Badía‐Vilas, 2016). These findings imply that the presence of carbonates in different forms in the soil profile is a common trait of soils in this area of the peninsula, as many are developed on calcareous and limestone‐derived parent materials, with climates that hinder complete leaching of carbonates.
Figure 1.3 Distribution of average annual rainfall (top), and temperature (center), and Köppen climate areas (bottom) in the Iberian Peninsula. Own elaboration from E‐OBS (Cornes et al., 2018), CRU‐TS 4.06 (Fick & Hijmans, 2017), and World Map of Köppen‐Geiger Climate Classification (https://koeppen‐geiger.vu‐wien.ac.at/).
Figure 1.4 Distribution of soil groups of the World Reference Base in the Iberian Peninsula (IUSS Working Group, 2015). Own elaboration from ESDAC, ESDB v2.0, 2004.
Figure 1.5 Distribution of Cambisols, Leptosols, Regosols, Luvisols, and Podzols in the Iberian Peninsula (IUSS Working Group, 2015). Own elaboration from ESDAC, ESDB v2.0, 2004.
In contrast, Cambisols in the northwest and areas with certain altitude appear as Dystric and/or Humic containing organic‐matter rich upper horizons (Figure 1.5), in many cases displaying a well‐structured, dark‐colored surface horizon with varying base saturation. The Soil Atlas of Europe (2005) depicts this area as mostly covered by Umbrisols with a dark, acid surface horizon rich in organic matter, which corresponds to climate in these regions, where precipitation considerably exceeds evapotranspiration, especially in the northern areas.
In a wide portion of the west and the southwest, Dystric and Eutric Regosols are also abundant (Figure 1.5). These are very weakly developed mineral soils occurring on unconsolidated materials in many cases and with limited development explained by climate limitations such as prolonged dryness, the parent material characteristics, or erosion. Regosols are extensive in eroding lands, in particular, in arid and semi‐arid areas and in mountainous regions (Soil Atlas of Europe, 2005). They correspond to Entisols in the USDA Soil Taxonomy and appear as Xerorthents in the description on the soils of Spain by Gómez‐Miguel and Badía‐Vilas (2016).
Finally, soils with leaching processes leading to the accumulation of clay (Luvisols) and/or organic matter (Podzols) appear mostly in the western half of the peninsula (Figure 1.5), the latter being especially abundant in central/western Portugal. Luvisols present a marked textural difference in the profile, with a subsurface horizon of high activity clay accumulation and high base saturation, corresponding to Alfisols in the USDA Soil Taxonomy. A wide range of parent materials and environmental conditions lead to great diversity in this soil group (Soil Atlas of Europe, 2005), which includes several subgroups (from Calcic and Chromic to Ferric and Gleyic) in the Iberian Peninsula. Podzols are bleached acid soils with a B horizon that accumulates aluminum, iron, and/or organic compounds. They mostly develop in humid, well‐drained areas and are common in Europe under vegetation with acidic litter (Soil Atlas of Europe, 2005). Other soil types can be dominant locally, such as Vertisols in the Guadalquivir area (Figure 1.4).
Finally, with respect to land cover and land uses, forests and shrublands (including some agroforestal areas such as the so‐called dehesas or montados) represent the most widespread land cover (252,550 km2, 42% of the geographic area), followed by farmlands used for different purposes (189,400 km2, 32%) and grasslands and badlands (102,506 km2, 32%). Less than 8% of the surface is associated with other types of uses (urban land, infrastructure, or water bodies; Figure 1.6). Agricultural and forest uses of soil are therefore the most widespread, and the ones with the greatest interactions with soil and soil health in this territory.
Figure 1.6 Land use in the Iberian Peninsula (top), and distribution of land use typologies in continental Spain (bottom left) and Portugal (bottom right) in 2021 and 2018, respectively.
Sources: Ministerio de Agricultura, Pesca y Alimentación (Spain) and Instituto Nacional de Estatística (Portugal) https://www.mapa.gob.es/es/estadistica/temas/estadisticas‐agrarias/agricultura/distribucion‐general‐suelo/https://www.ine.pt/xportal/xmain?xpid=INE&xpgid=ine_destaques&DESTAQUESdest_boui=435668469&DESTAQUESmodo=2&xlang=pt.
In relation to agriculture, available statistics differ between Spain and Portugal. In Spain, data from the Ministry of Agriculture (Ministerio de Agricultura, Alimentación y Medio Ambiente, 2022) indicate that herbaceous crops represent 53% of the total agricultural land, and woody permanent crops, 30.5%. The other 16.7% includes fallow or abandoned agricultural land. Almost one‐fourth (23.2%) of this land is irrigated. Grasslands and grazelands (included grazed badlands) account for 10.6% and 8.4%, respectively, of this land use, with less than 1.5% being irrigated (Figure 1.6). Forest and shrublands represent 39.5% of the continental land cover of Spain (~200,000 km2).
In Portugal, 132,562 ha of land was irrigated in 2013 (Governo do Portugal, 2014), which represents 5.7% of the total agricultural land, while forests and shrublands (including montados) represent 59.5% of the total surface. Farmland as a whole account for 26.2%.
All these data support the idea that major threats to soil health in the Iberian Peninsula arise from the agricultural and forestry use of the soils.
Historical Assessment
To describe the evolution of scientific publications developed in the Iberian Peninsula concerning the concepts related to soil health, a bibliometric analysis was conducted. We collected data on the evolution of publications that refer not only to soil health but also to those related to soil quality, in order to observe the evolution of these concepts. Specific publications on both topics indexed in the Scopus database (Elsevier, Germany) until May 2024 were searched, avoiding publications in which only the concept of soil quality or soil health was mentioned without deeper exploration. The first search criterion was TITLE (“soil health” OR “soil quality”). A second search criterion TITLE‐ABS‐KEY (Spain OR Portugal OR iberi* OR mediterr*) was applied to focus on studies conducted in the Iberian Peninsula. Preliminary filtering was necessary to discard publications outside the desired geographic scale, especially among those collected with the “mediterr*” criterion. The results were filtered by type of document, focusing on articles, reviews, and book chapters. In addition to categorizing the studies by topic, the R package bibliometrix (Aria & Cuccurullo, 2017) was used to create a simple scientific map that provided information concerning the evolution of annual scientific production and the most frequently employed keywords and terms.
Although many references in the so‐called gray literature were likely missing, and even some works referred in Scopus may have also escaped filtering, the database generated is representative of the trends observed in Portugal and Spain in the past few decades. The database contained 115 papers published from 1999 to 2024, with 107 related to soil quality and eight to soil health. Two of the papers proposed a mixed evaluation of both concepts and were included in the soil health analysis. The documents comprised 113 scientific articles and two book chapters. Seven conference papers were discarded. The number of publications showed a positive and growing trend in research related to soil quality since the late 1990s, with a later emergence of publications related to soil health starting in the 2010s and becoming more prominent from 2017 onwards (Figure 1.7).
Among the publications on soil quality, 78 (73%) focused on agricultural soils, eight (7%) on forest soils, and seven (7%) on mountain soils (Figure 1.8). Of the mountain soil publications, five specifically examined mid‐mountain agricultural systems. Six publications (6%) addressed soil quality in degraded soils, including studies in industrial and mining areas. Finally, 10 publications investigated mixed land uses, evaluating soils under various uses or targeting different ecosystems and topics. Examples include studies on soil quality in fluvial systems (Rodrigo‐Comino et al., 2023), seagrass sediments as a palaeoecological land use and soil quality proxy (López‐Merino et al., 2015), and the relationship between soil quality and plant invasion (Novoa et al., 2014).
Figure 1.7 Evolution of scientific production on soil quality (red line, primary axis), soil health (green line, secondary axis), and total publications (gray shade, primary axis).
Figure 1.8 Topic categories considered within soil quality publications.
The most frequently mentioned terms within the soil quality publications (each mentioned more than 15 times, excluding the terms soils, soil quality, and Spain) were the following: organic carbon, soil organic matter, enzyme activity, agriculture, Mediterranean environment, soil pollution, soil properties, soil management, Mediterranean region, and soil degradation (Figure 1.9).
Figure 1.9 Wordcloud with the 50 most frequent terms within soil quality publications.
With respect to publications specifically addressing soil health, four focused on soil health assessment in agricultural soils, and two focused on polluted soils, including one on soil in mining area and another one on industrial soils. Finally, two publications focused on soil health assessment in different land uses and land covers (Table 1.1).
Asensio et al. (2013) defined soil ecosystem health as the “ability of a soil to carry out its functions in an appropriate way for the ecosystem operation,” and proposed an integrated soil health assessment strategy based on biomarkers (earthworms) for contaminated industrial soils. In the other publication on polluted soil restoration, Cárdenas‐Aguiar et al. (2022) proposed a soil remediation strategy for mining areas using rabbit manure‐derived applications combined with plant cover to enhance soil enzyme activities and soil microbial biomass.
Regarding agricultural soils publications, Sánchez‐Moreno et al. (2018) studied the effect of organic management in olive groves and vineyards on soil health, based on nematode diversity and other soil properties. The authors highlighted the importance of preserving and improving the health of agroecosystems as a priority for landscape management, especially in southern Europe. Other publications on agricultural soils followed a similar line, evaluating various agricultural strategies to improve soil health. For example, Zuazo et al. (2020) concluded that alternative modifications to conventional production systems for rainfed olive orchards, based on organic, integrated, and conservation agriculture, could improve important soil health features.
Table 1.1 Soil Health References.
Reference
Study areas
Land/soil use
Topic
Type
1
Visconti et al.,
2024
Valencia (Spain)
Agricultural soils
Straw mulching strategies to increase soil health
Article
2
Rutigliano et al.,
2023
Alentejo (Portugal), Extremadura (Spain), and Sicily (Italy)
Mixed use
Soil health indicators for different land cover types
Article
3
Zegada‐Lizarazu et al.,
2022
Cadriano (Italy), Extremadura (Spain), and Aliartos (Greece)
Agricultural soils
Effects of integrated food and bioenergy cropping systems on crop yields, soil health, and biomass quality
Article
4
Cárdenas‐Aguiar et al.,
2022
Murcia (Spain)
Mining soils
Effects of on soil health and quality in mine soils
Article
5
Zuazo et al.,
2020
Granada (Spain)
Agricultural soils
Organic olive rainfed systems to control soil erosion and improve soil health
Article
6
Higueras et al.,
2019
Castilla‐La Mancha (Spain)
Mixed use
Biogeochemical indicators to assess soil quality and health
Book chapter
7
Sánchez‐Moreno et al.,
2018
Castilla‐La Mancha (Spain)
Agricultural soils
Organic management to improve soil health: microfaunal soil food webs
Article
8
Asensio et al.,
2013
Basque Country (Spain)
Industrial soils
Integrative soil health assessment strategy
Article
Higueras et al. (2019) briefly reviewed the evolution of the concepts of soil quality and soil health, updating the definition of soil health as “the continued capacity of the soil to function as a vital living ecosystem that sustains plants, animals, and humans”, emphasizing that soil health assessment involves identifying and quantifying the temporal evolution of soil quality. They argued that soil health assessment should focus on the integration and optimization of soil chemical, physical, and biological characteristics, which are fundamental for sustained productivity and environmental quality. This publication, in the form of a book chapter, briefly presents three case studies in Castilla la Mancha (Spain), one on agricultural soils and two on soils in mining areas.
Finally, Rutigliano et al. (2023) integrated the most current definition of soil health proposed by Bünemann et al. (2018) as “the ability of a soil to function within ecosystems and land use boundaries to sustain biological productivity, maintain or improve environmental quality, and promote plant and animal health,” complementing it with the definition suggested by the European Commission (2020): “the continued capacity of soils to support ecosystem services.” The authors emphasized in this work that a comprehensive understanding of soil properties and functions is a prerequisite for implementing effective strategies to prevent the risk of desertification. They proposed a set of microbial, physical, and chemical indicators to assess soil health.
Figure 1.10 Wordcloud with the 50 most frequent terms within soil health publications.
The most frequently mentioned terms within the soil health publications (each mentioned more than three times, excluding the terms soils, soil quality, and Spain) were the following: Eisenia fetida
