The authors, Rogelio Pérez Moreira and María Teresa Barral Silva, frame their argument around a simple observation: soil is usually shown only at its surface, and rarely in profile, the three-dimensional cross-section that soil scientists study. A soil profile only becomes visible in a painting when the ground is cut open, along a road cutting, a slope or an escarpment. Yet even then, the internal differentiation of horizons would rarely be observable without deliberate excavation, something inconceivable in eras long before scientific soil study. The striking exception, they find, is that certain paintings show textures, colors and chromatic sequences that correspond to real soil features identifiable today, including dark surface horizons and even the bleached eluvial and reddish illuvial layers of podzols.

The precursors are revealing. Medieval and Renaissance artists showed soil mainly as surface, as in the plowed fields of the Très Riches Heures du Duc de Berry from 1413 to 1416 or Pieter Brueghel the Elder’s The Fall of Icarus from around 1558 to 1560. Where the ground was opened, as in works by Rogier van der Weyden, Hans Memling, Hieronymus Bosch or Giorgione, the exposed earth often carried symbolic weight, serving as an allegory of resurrection or an excuse to display roots with their own emblematic meaning. Occasionally a real profile emerges, as in Giovanni Agostino da Lodi’s Pan and Syrinx of around 1510, where a darkened A horizon shows above a talus, or in the deep reddish-brown cuttings of 17th-century Flemish painter Lodewijk de Vadder. But these remain exceptions against a convention in which soil was scenery, not subject.

The first true flowering came with the birth of landscape painting itself. Art historians generally agree that landscape became an autonomous genre at the start of the 17th century in the Nordic countries, and definitively in Holland. The context was revolutionary: the Seven United Provinces had declared independence from Spain in 1579, Protestantism replaced Catholicism, and a powerful commercial bourgeoisie transformed the art market. With courtly and ecclesiastical patronage gone, and the Reformed Church proscribing religious imagery, the new merchant class collected small-format paintings of the world around them. By mid-century, landscapes made up nearly 40 percent of Dutch artistic production, bought by all classes of society, driven by civic pride in a free country, nostalgia for a rural past among an increasingly urban population, and a special relationship with land reclaimed from wetlands around Haarlem and Amsterdam.

Dutch painters rarely finished canvases outdoors, but they went into the field to sketch from nature, and those excursions let them perceive details and subtleties that studio-bound traditions had never registered. The result was a naturalism built on thorough observation of specifics, even if the final works were believable reconstructions rather than literal transcriptions. Crucially for soil scientists, much of the Netherlands sits on drifting sand deposits, whose buried paleosols commonly show podzolic characteristics, with a pale leached E horizon above a dark spodic B horizon. A whole school of painters specialized in dune landscapes: Esaias van de Velde, Jan van Goyen, Pieter de Molijn and Salomon van Ruysdael established a tonal phase of warm grays and earth tones, later monumentalized by Jacob van Ruisdael, Meindert Hobbema and Philips Wouwerman.

The profiles in these paintings grow steadily more eloquent. Aelbert Cuyp’s river scenes and wooded landscapes show the dark surface horizon clearly. Salomon van Ruysdael’s Landscape with Sandy Road of 1628 presents an upper horizon thick with roots. But the standout is Jan Wijnants of Haarlem, who devoted his entire career to dune paintings. After moving permanently to Amsterdam in December 1660, his canvases began showing soil details that the authors describe as exceptional for their time and undoubtedly the result of prior observation. In works such as The Dunes near Haarlem of 1667, the dark A horizon sits above the dune substrate, and in several paintings the pale eluvial E horizon and the underlying illuvial spodic B horizon of a podzol can be distinguished, a sequence any soil scientist would recognize today.

The second flowering came two centuries later, in the 19th century, when industrial prosperity empowered a new bourgeoisie and artists, freed from painting the grandeur of monarchs, developed their individuality and absorbed the excitement of the natural sciences. The Dutch masters themselves became the models: Thomas Gainsborough and John Constable studied Ruisdael, Hobbema and Wijnants with devoted admiration, and the Dutch contribution to European landscape was ultimately its naturalism. Plein air painting, rare and technically difficult before the invention of paint tubes and portable easels at mid-century, became a genuine practice. Romanticism had elevated landscape to academic respectability; Realism then demanded that nature be reproduced truthfully, as John Ruskin urged in Modern Painters, without rejecting, choosing or despising anything. Natural elements were no longer decorative props but singular entities reproduced according to their own reality.

Three schools carried this new naturalism, and all three left soil records. In England, Constable, painting outdoors from 1810 onward, showed the soil profile clearly in works such as Dedham Vale of 1802 and Dell at Helmingham Park from the mid-1820s, where the surface horizon and other features are distinguishable. In France, the creation of the Grand Prix de Rome for historical landscape in 1817 sent candidates into the Forest of Fontainebleau for the dreaded tree test, seeding the Barbizon School. Early figures Georges Michel and Làzare Bruandet showed profiles in Fontainebleau scenes, and Jacques-Raymond Brascassat, who studied in Italy after winning second prize in 1825, made the soil profile evident in Rochers en forêt of 1828, while Jean-Baptiste-Camille Corot’s Carrière de Chaise-Marie à Fontainebleau of 1831 offers a deliberately unpicturesque fragment of nature that appears drawn directly from life, soil included. In the Netherlands, the Hague School’s Willem Roelofs, who visited Fontainebleau three times, rendered soil with meticulous realism, whether as the surface of an old riverbed or in his detailed Forest of Fontainebleau.

The authors’ conclusion is that the most faithful pictorial representations of soil in Western art coincide precisely with the two periods when naturalistic landscape painting flourished, the 17th and 19th centuries, because exceptional social and cultural circumstances favored open-air observation. When those circumstances vanished, so did the soil. The 18th century’s academic criteria and the late 19th century’s turn toward Impressionism, Symbolism and eventually abstraction replaced faithful description with conceptual and subjective codes, and the recognizable soil profile disappeared from painting. Under modern aesthetics, external reality gave way to visions born from the artist’s spirit, and soil returned to being scenery, or in contemporary Land Art and Eco Art, a physical medium rather than an image.

Why does this matter beyond art history? The researchers argue that paintings can serve as a documentary source and cultural indicator, testifying to how soil was perceived in periods long before pedology, a science only about 150 years old with the Russian scientist Vasily Dokuchaev as its founding reference. Artistic images of soil, they suggest, can also help soil scientists communicate with a broader public, attracting attention beyond the restricted audience of specialists and opening an interdisciplinary dialogue between science and the humanities. In an era when soil degradation and security are urgent global concerns, the idea that a 17th-century dune painting can double as a pedological document, and that Dutch Golden Age canvases once helped a young republic celebrate its land, gives one of humanity’s most overlooked resources an unexpectedly vivid cultural afterlife.

Subject of Research: The representation of soil and soil profiles in naturalistic landscape painting of the 17th and 19th centuries

Article Title: Soil in Art. Its Representation in Naturalistic Painting of the 17th and 19th Centuries

Article References: Pérez Moreira, R., & Barral Silva, M. T. (2025). Soil in Art. Its Representation in Naturalistic Painting of the 17th and 19th Centuries. Spanish Journal of Soil Science, 15, Article 14834. https://doi.org/10.3389/sjss.2025.14834

Image Credits: AI Generated

DOI: 10.3389/sjss.2025.14834

Keywords: soil science, pedology, art history, landscape painting, Dutch Golden Age, Barbizon School, Hague School, John Constable, Jan Wijnants, soil horizons, podzol, plein air painting

The authors ground their argument in a principle that has been on the books for more than half a century. The European Soil Charter of 1972 stated that soil conservation principles must be fully included in teaching programs at all levels as an element of environmental education, at primary, secondary, and university levels alike. Despite that long-standing recommendation, the editorial notes that soil is virtually absent from school curricula in many regions, and that future schoolteachers frequently receive no training in the subject at all. The result is a generational gap in understanding: students who never learn about soil degradation processes or conservation measures grow into adults, and sometimes into policymakers and educators, who lack the conceptual tools to address one of the planet’s most consequential natural resources.

Part of the problem, the editorial argues, lies in the training of teachers themselves. Not all teachers at primary and secondary levels possess in-depth knowledge of soil, and without knowledge, confidence, and motivation, even the most dedicated educator will struggle to convey the fascination and importance of the soil resource. The editorial highlights an approach developed by a researcher at the University of Lorraine, described in a contribution to the Special Issue, that uses project-based learning to close this gap. Future primary school teachers, enrolled in a multidisciplinary bachelor’s degree in education, design and implement an educational activity on soil in an elementary school classroom. By building and delivering a lesson themselves, these students explore soil science hands-on while simultaneously learning how to teach it, a dual outcome that conventional lecture-based training rarely achieves.

The emotional dimension of soil teaching emerges in the editorial’s references to the widely cited article The Joy of Teaching Soil Science, in which soil scientist Megan Balks describes the joy, and serious responsibility, of watching some students awaken to the fascination, intrinsic beauty, and importance of the soil resource. That awakening, the editorial suggests, is precisely what good soil education should aim for. The teacher’s role is to provide a solid foundation, spark curiosity, and equip students with conceptual and methodological tools that allow them to delve deeper on their own: asking questions, analyzing data, and applying soil science to real agricultural and environmental problems. In other words, the goal is not rote memorization of soil taxonomy but the cultivation of a generation capable of independent scientific reasoning about the ground beneath their feet.

At the university level, the editorial identifies a different but equally pressing challenge: aligning soil science with sustainability. A contribution from researchers including scientists at Sultan Qaboos University in Oman argues that soil science curricula should be redesigned from a sustainability perspective, transforming soil from a mere technical physical medium into a form of natural capital and a dynamic agent of sustainable transformation. The authors draw on case studies from the Bachelor of Science in Soil Sciences at Sultan Qaboos University and from Moscow State University, and they propose a forward-looking curriculum built on systems thinking and real-world engagement. Their framework incorporates integrative approaches such as One Health, Soil Security, and the Pedometrics Challenges, and it highlights pedagogical innovations including inquiry-based learning, structured debates, and community projects designed to foster interdisciplinary thinking among students.

The stakes of this curricular reform are quantifiable. Soils contribute directly to at least 14 of the 17 United Nations Sustainable Development Goals, spanning food security, water purification, climate regulation, and biodiversity. Despite this extraordinary breadth of influence, the editorial emphasizes that soil’s importance is not explicitly recognized in the SDG framework itself, which reinforces the need for transformative education worldwide. Luisa Reyes-Sánchez, writing from the perspective of the International Union of Soil Sciences, argues that the deterioration of soil resources generates environmental, social, and economic problems that cascade into poverty, inequality, and resource conflicts. In her view, national soil science societies and the IUSS carry a moral obligation to promote soil protection through education and public awareness, precisely because these are the key tools for achieving the SDGs.

Reyes-Sánchez’s contribution goes beyond rhetoric to propose a concrete methodological shift. It is not enough, she argues, to transmit technical knowledge; educators must cultivate values, attitudes, and environmental awareness about soil from an early age, using a systemic approach in which soil serves as the integrating element across different disciplines. The IUSS has adopted two main priorities: halting soil degradation and focusing educational efforts on children and young people, who will become the future stewards of this resource. To pursue those goals, the union advocates training students, scientists, and teachers to communicate science in accessible ways, professionalizing the teaching of soil science, integrating digital technologies, and promoting the participation of governments, educational institutions, and civil society.

The most visible expression of that agenda is The IUSS Goes to School, a project launched in 2019 with the objective of bringing soil science directly to children and young people through educational materials, activities, and digital resources. Its avenues of dissemination have included children’s stories, cultivation fact sheets developed by scientists, educational books published in several languages, organized competitions, and collaboration with international organizations such as the Food and Agriculture Organization of the United Nations. The project exemplifies the editorial’s central claim that soil science must move out of the laboratory and into everyday culture if society is to develop the practical understanding needed for responsible soil management. Reyes-Sánchez’s conclusion is a direct call to action: scientists and educators must move from words to action and actively engage in the education of new generations.

There are signs that momentum is building. The editorial credits the International Decade of Soils, proclaimed by the IUSS for 2015 through 2024, with producing a significant rise in awareness of soil health, and notes that a wave of educational and outreach projects aimed at improving soil literacy received funding during that period. Among them are LOESS and CURIOSOIL, alongside initiatives such as PREPSOIL, which works to encourage teachers to incorporate soil-related topics into their teaching by identifying and promoting innovative examples of soil education. The editorial also points to a growing literature on soil science education across multiple countries, and to a book, Soil Sciences Education: Global Concepts and Teaching, that outlines the concepts, philosophy, and key principles for designing soil curricula from preschool through adult learning.

The editorial closes with a forward-looking assessment: although a considerable body of literature on soil science education now exists, much remains to be done to raise awareness across all sectors of society. Promoting sustainable lifestyles among young people, the authors argue, entails responsible and sustainable soil management, and it will help ensure that future generations understand why soil must be cared for. Soil science education, they note, is evolving alongside new teaching methodologies, recent advances in the discipline, and the integration of artificial intelligence in schools and universities, a convergence that demands rigorous educational research. What emerges from the Special Issue as a whole is a coherent vision: soil science should no longer be treated as a technical sub-discipline tucked into agricultural faculties, but as a strategic catalyst for a sustainable planet, taught early, taught well, and taught everywhere.

Subject of Research: Soil science education and curriculum reform across primary, secondary, and university levels

Article Title: Editorial: Teaching and researching in soil science

Article References: Lull, C., Moreno, H., & Roca, L. (2026). Editorial: Teaching and researching in soil science. Spanish Journal of Soil Science, 16, Article 16650. https://doi.org/10.3389/sjss.2026.16650

Image Credits: AI Generated

DOI: 10.3389/sjss.2026.16650

Keywords: soil science, soil education, curriculum reform, sustainability, SDGs, teacher training, International Union of Soil Sciences, soil literacy, project-based learning, natural capital, soil health, education

The editorial, published in Volume 16 of the journal, was written by Alberto Enrique, Íñigo Virto, Avelino Núñez Delgado, Jorge Mataix-Solera, and Irene Ortiz-Bernad, researchers affiliated with Spanish universities including the Universidad Pública de Navarra, the Universidade de Santiago de Compostela, the Universidad Miguel Hernández de Elche, and the Universidad de Granada. They describe a scientist whose legacy was simultaneously scientific, educational, and institutional. Porta was a co-founder and Secretary of the Editorial Board of the Spanish Journal of Soil Science and served as President of the Spanish Society of Soil Science, an organization known by its Spanish acronym SECS. Perhaps most notably, he worked tirelessly to strengthen the connections between the Spanish and Latin American Soil Science Societies, building bridges across the Atlantic at a time when such collaboration was far from routine.

The special issue opens with a contribution by Alcañiz and colleagues that gathers personal and professional reflections from disciples, colleagues, and friends of Porta, offering an intimate portrait of a career that shaped generations of soil scientists. The tribute article reviews his pioneering work on salt-affected soils and gypsum-rich soils, two notoriously difficult materials that demand specialized analytical approaches, along with his contributions to soil mapping and the standardization of laboratory methods. Special emphasis is placed on his textbooks, which became foundational references for Spanish-speaking students, and on his international training initiatives that carried rigorous soil education far beyond Spain’s borders. His role in strengthening scientific institutions, journals, and the public dissemination of soil knowledge emerges as a defining thread of the tribute.

From this personal opening, the issue pivots to the kind of applied research Porta championed. Abbas and colleagues assessed the effects of biochar applied at three percent, combined with compost and animal manure at concentrations between 0.5 and 1 percent, on soil carbon fractions, soil properties, and maize growth in low-fertility soil. The results were striking: biochar combined with one percent compost significantly improved plant growth, soil organic matter, microbial biomass, and the carbon pool index, a metric that tracks how effectively soil stores and protects carbon. In an era when agriculture is under pressure to rebuild degraded soils while feeding a growing population, the findings position organic amendments as a sustainable strategy that simultaneously enhances crop productivity and supports a circular economy under changing climate conditions.

Water and salt management, topics close to Porta’s own research on salt-affected soils, feature prominently in the issue. Altés and colleagues analyzed salt dynamics and drainage loads in a newly established irrigation district in the Ebro basin in northeastern Spain between 2021 and 2023, a period that included the severe drought of 2023. By monitoring two sub-basins, the researchers found that a 31 percent reduction in irrigation delivery produced a 73 percent decrease in drainage and a 70 percent reduction in salt exports. The numbers carry a double message. On one hand, irrigation restrictions can dramatically improve water and salt management, preventing the salinization that has ruined farmland since antiquity. On the other hand, the restrictions came with associated yield losses, a reminder that every water management decision involves trade-offs between conservation and production.

Fire and vegetation management were also on the agenda. Quintana-Esteras and colleagues evaluated the effects of prescribed burning and selective shrub clearing on subalpine soils and vegetation in the Central Pyrenees, two techniques widely used to control shrub encroachment in mountain pastures. Both treatments similarly increased soil pH and reduced several physical and chemical properties, while microbial functional diversity remained stable, suggesting a degree of resilience in the soil microbial community. However, mechanical clearing enhanced soil microbial activity compared to burning, and two years after the interventions, shrub cover remained low in both treatments, although prescribed burning resulted in more bare soil and reduced plant diversity than selective clearing. For land managers weighing these options, the study offers a nuanced picture in which the gentler mechanical approach appears to preserve more of the ecosystem’s biological fabric.

Precision agriculture takes center stage in the work of Aguirre-Arcos and colleagues, who assessed sap analysis as a rapid diagnostic tool for the nutritional status of olive trees under integrated production in southern Spain. Across trials on five farms, the researchers documented clear seasonal nutrient fluxes in the sap, shaped by climate and the trees’ phenological stages. Comparisons among sap, leaf, and soil analyses highlighted the dominance of potassium in sap and revealed climate-driven variability in micronutrients. The technique does not replace traditional methods, but it complements them, supporting more precise and balanced fertilization strategies in olive orchards, an economically vital crop in the Mediterranean where over-fertilization wastes resources and under-fertilization erodes yields.

Two contributions underscore the cultural and institutional dimensions of soil science, areas where Porta’s influence was profound. Usón Murillo and colleagues analyzed initiatives to harmonize soil analytical methods in Spain through interlaboratory proficiency tests promoted by the Spanish Society of Soil Science and partner institutions. Results from tests conducted in 2019 and 2021 revealed significant methodological differences among laboratories, with only partial improvements in performance and persistent weaknesses, particularly in organic matter and texture analyses. The study makes a compelling case for regular proficiency testing, arguing that reliable soil data underpin sustainable soil management and effective policy implementation. Without comparable measurements, soil data cannot be aggregated, compared, or trusted at regional or national scales.

In an unexpected turn, Pérez Moreira and Barral Silva explored the rare but significant representation of soil in Western landscape painting, identifying periods of naturalistic art, particularly seventeenth-century Dutch painting and the nineteenth-century European landscape schools, when artists depicted soils with unusual detail. Some of these works reveal recognizable soil horizons and features that can be interpreted using modern soil science, effectively turning canvases into historical soil archives. The study contextualizes these artistic representations historically and culturally, illuminating the intersections between art, the observation of nature, and soil knowledge, and demonstrating that the scientific and humanistic study of land are not separate endeavors but parallel ways of reading the same surface.

The issue closes with two studies that tie the threads together. Barreiro and colleagues examined the influence of tree species on soil properties and microbial activity across 54 forest plantations in Galicia, northwestern Spain, finding generally acidic soils with high organic matter and low phosphorus contents. Moisture varied by vegetation, with the driest soils under eucalyptus and birch and the wettest under shrublands, while microbial respiration was highest in walnut soils and lowest under eucalyptus. The results carry direct implications for climate-adaptive forestry planning, since tree species selection shapes soil microbial function and carbon stabilization. Finally, Tierra and colleagues investigated soil salinity in the rainfed landscapes of the Saladas of Sástago-Bujaraloz in the Central Ebro Basin, analyzing 319 soil samples alongside electromagnetic sensor readings. They found highly variable and often extreme salinity, with 73 percent of samples classified as very strongly saline, and the strongest sensor correlations at depths of 0 to 100 centimeters. Their proposal to incorporate soil salinity as an agronomic criterion within the EU Common Agricultural Policy, recommending the exclusion of plots with electrical conductivity above 10 dS per meter, a threshold exceeded across more than half of their study area, shows how the science Porta devoted his life to can flow directly into European policy. Together, these contributions form a fitting memorial: a portrait of soil science as a living, interdisciplinary enterprise, from laboratory benches and olive groves to mountain forests, museum walls, and the halls of Brussels.

Subject of Research: A memorial special issue of Spanish soil science research honoring soil scientist Jaume Porta Casanellas

Article Title: Editorial: Jaume Porta Casanellas – RENS Soil Science

Article References: Enrique, A., Virto, Í., Delgado, A. N., Mataix-Solera, J., & Ortiz-Bernad, I. (2026). Editorial: Jaume Porta Casanellas – RENS Soil Science. Spanish Journal of Soil Science, 16, Article 16319. https://doi.org/10.3389/sjss.2026.16319

Image Credits: AI Generated

DOI: 10.3389/sjss.2026.16319

Keywords: soil science, Jaume Porta Casanellas, Spanish Journal of Soil Science, soil salinity, biochar, soil organic matter, prescribed burning, olive trees, interlaboratory proficiency testing, forest soils, soil education, Ebro basin

The formal recognition will take place on November 3 during CANVAS 2026, an international meeting that brings together multiple scientific communities involved in crop, agronomic, environmental and soil science research. The meeting is expected to attract more than 4,000 scientists and innovators with a shared interest in global agricultural success, making it one of the largest gatherings of its kind. For Zhuang, the ceremony will cap a career that has spanned fundamental research into how water, contaminants and microorganisms move through soil, as well as applied work aimed at helping small farms operate more sustainably.

Fellowship in the Soil Science Society of America is not awarded for a single discovery. According to the society, recipients are recognized for significant contributions to research, education, industry, Extension and leadership, as well as their lasting impact on soil science and the broader scientific community. That breadth matters because soil science itself is an unusually integrative field. It sits at the intersection of physics, chemistry, biology and engineering, and its findings shape everything from crop productivity and water quality to carbon sequestration and disease transmission. A Fellow is expected to have moved the field forward on more than one of those fronts.

Zhuang’s research portfolio illustrates that integrative character. His published work ranges across the food-energy-water nexus, a framework that treats food production, energy generation and water resources as a tightly coupled system rather than as separate problems. The nexus approach has become increasingly influential in sustainability science because interventions in one domain often produce unintended consequences in the others. Irrigation, for example, links crop yields directly to energy use and aquifer depletion, and biofuel production can compete with food crops for both land and water. Studying these linkages requires the kind of cross-disciplinary modeling and experimentation that Zhuang’s group has pursued.

Another major thread of his research concerns the fate and transport of contaminants in soil and water systems. This line of inquiry addresses a remarkably wide array of agents, including viruses, bacteria, organic pollutants, heavy metals, engineered nanoparticles and nutrients. Each of these moves through porous media according to different physical and chemical rules. Viruses and bacteria, for instance, are transported by water flow but their retention in soil depends on factors such as pore size distribution, surface chemistry and electrostatic interactions. Heavy metals bind to soil particles through adsorption and precipitation reactions that are highly sensitive to pH and redox conditions. Engineered nanoparticles, an increasingly common class of environmental contaminants, present transport behavior that can differ sharply from that of dissolved chemicals, which is why their movement through soils has become a growing focus of environmental research.

Zhuang’s work also extends into soil hydrology modeling and pore-scale carbon-water interactions, areas that address some of the most fundamental questions in the discipline. Soil hydrology models predict how water enters, moves through and leaves the soil profile, and those predictions underpin flood forecasting, irrigation scheduling, groundwater recharge estimates and climate models. Pore-scale studies, by contrast, examine processes at the level of individual soil aggregates and the thin water films that coat mineral and organic surfaces. At that scale, the physical arrangement of pores determines where carbon compounds and water coexist, which in turn controls microbial access to organic matter and therefore the rate at which soil carbon is stabilized or released. Understanding these microscale interactions is considered essential for improving predictions of soil carbon dynamics under changing climate and land management conditions.

His research interests further include root water uptake and the physical foundations of phage-host interactions. Root water uptake is a central process in vadose zone hydrology, linking soil water availability to plant transpiration and crop productivity, and its modeling remains a challenge because roots alter the hydraulic properties of the soil around them as they grow. The study of phage-host interactions connects soil physics with microbiology. Bacteriophages, the viruses that infect bacteria, are now widely studied as modulators of microbial communities in soils and other environments, and the physical conditions governing how phages encounter and attach to their hosts are relevant both to understanding natural microbial ecology and to developing phage-based approaches for managing pathogens.

Zhuang’s most recent endeavors include studies of the food-energy-water nexus on small farms within the framework of the circular bioeconomy. The circular bioeconomy concept promotes the reuse and recycling of biological resources so that waste streams from one process become inputs for another, reducing reliance on finite resources and closing nutrient and energy loops. On small farms, this can involve practices such as converting agricultural residues and manure into energy or soil amendments, and it raises practical questions about economics, logistics and policy. Zhuang is among the editors of the recently published open access Handbook of Circular Bioeconomy, a guide intended for students and professionals that addresses future farming activities which could reshape urban-rural relationships. The handbook covers policy and engineering practices in global communities aimed at facilitating natural resource-based industries that address biosecurity, conservation and other global concerns.

Beyond his research, Zhuang has held a series of leadership and service roles at the University of Tennessee. He is currently a member of the UTIA Advisory Council. He served as faculty director of environmental and soil science graduate studies for his department from 2022 to 2026, and he has been the faculty lead of the UT Cluster Hiring Initiative for Resilient Agriculture and Forest Systems as well as the RAFS Community of Scholars in recent years. He has also received numerous faculty awards over the course of his career. In addition to his new SSSA honor, he is already a Fellow of the American Association for the Advancement of Science, one of the most widely recognized distinctions in the scientific community, and he is affiliated with the Institute for a Secure and Sustainable Environment at the University of Tennessee.

Zhuang received his B.S., M.S. and Ph.D. degrees in soil science from Shenyang Agricultural University in China, an academic path that took him through the full range of the discipline he now helps lead. His election as a 2026 Fellow of the Soil Science Society of America places him in a small group honored by the society in a given year and underscores the growing recognition that soil science, long a comparatively quiet corner of the agricultural sciences, is central to some of the most pressing questions of the era, from water security and contaminant control to carbon management and the design of resilient farming systems. The formal presentation at CANVAS 2026 will bring that recognition before an audience of thousands of researchers working on precisely those problems.

Subject of Research: Election of a University of Tennessee soil scientist as a 2026 Fellow of the Soil Science Society of America

Article Title: 2026 SSSA Fellows includes University of Tennessee soil scientist

Article References: 2026 SSSA Fellows includes University of Tennessee soil scientist. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Soil Science Society of America, Jie Zhuang, SSSA Fellows, University of Tennessee, soil science, food-energy-water nexus, contaminant transport, soil hydrology, circular bioeconomy, CANVAS 2026, agricultural research, scientific honors

The significance of the advance lies in what it replaces. Until now, researchers attempting to gauge melanin in soils had to rely on DNA-based approaches, which estimate only the genetic potential for melanin production within the microbial community. Such methods can reveal which organisms carry the genes for melanin biosynthesis, but they say nothing about whether the pigment is actually produced, deposited, and preserved in the soil matrix. Because gene presence and pigment abundance can diverge dramatically under different environmental conditions, DNA-based evidence remains indirect. For a field trying to build quantitative models of carbon stabilization, that gap has been a fundamental constraint.

Melanin itself is a chemically formidable class of pigments. In fungi, these dark, high-molecular-weight polymers are built from phenolic and indolic precursors and form the structural backbone of cell walls in many species, particularly the melanized (dematiaceous) fungi that dominate leaf litter and soil surfaces. The same chemical recalcitrance that makes melanin resistant to degradation by enzymes and oxidants in living fungi persists after cell death, meaning fungal necromass rich in melanin should, in principle, resist microbial attack and persist in soil far longer than more labile organic matter. This is the mechanistic logic behind the hypothesis that melanized fungal residues contribute disproportionately to the stable fraction of soil organic carbon.

Testing that logic requires numbers, and generating those numbers required the Finnish team to first rule out the obvious measurement routes. The researchers evaluated spectroscopic and spectrophotometric assays, techniques that measure how molecules absorb or interact with light and are often the fastest, cheapest options for pigment quantification. Both approaches proved insufficiently specific for soil work. The problem is interference: soils contain a dense cocktail of chemically related compounds — humic substances, tannins, lignin fragments, and other aromatic polymers — whose optical signatures overlap with those of melanin. In a matrix as complex as soil, a spectrophotometric signal attributed to melanin could just as easily reflect any of these look-alike molecules, rendering the measurement unreliable.

The solution the authors introduce is chromatographic separation. Liquid chromatography physically resolves the components of a soil extract before detection, allowing melanin-derived compounds to be distinguished from the chemically related interferents that defeated the spectroscopic methods. With separation achieved, the method enables quantification of the major fungal melanin types present in soil samples, converting what was previously a qualitative suspicion into a measurable concentration. The framework, the authors write, allows longstanding hypotheses regarding melanized fungal necromass and soil carbon stabilization to be tested mechanistically rather than inferred from gene surveys or circumstantial evidence.

Applying the method to real soils produced a striking result: soil melanin concentrations were strongly correlated with total soil carbon. That correlation supports a central role for fungal melanin in long-term soil carbon stabilization, the authors report. In other words, soils that accumulate more of this fungal pigment also tend to hold more carbon overall, consistent with the idea that melanin-rich necromass is not merely a passive ingredient of soil organic matter but a structurally important one. While a correlation across soils does not by itself prove causation, it provides exactly the kind of quantitative, direct evidence that the field has lacked and that mechanistic models of carbon cycling require.

The broader context makes this finding timely. Global carbon models increasingly recognize that the persistence of soil organic carbon depends less on the intrinsic recalcitrance of plant litter alone and more on the microbial products that get incorporated into soil — a pool in which dead microbial cells, or necromass, feature prominently. Fungi, with their chitinous and often melanized cell walls, are major contributors to this necromass pool. If a substantial fraction of stable soil carbon is built from melanized fungal residues, then factors that shift fungal community composition — land-use change, nitrogen deposition, warming, altered precipitation — could have cascading effects on carbon residence times that current models do not capture. A direct measurement tool for melanin makes it possible to begin quantifying those effects.

The methodological rigor behind the study reflects a careful, multi-stage validation process. The authors document that they systematically tested the simpler optical approaches before committing to chromatography, and the paper’s transparent peer review file and reporting summary, published alongside the article, lay out the analytical details for scrutiny. The work was supported by the Research Council of Finland under several grants, and the team acknowledges collaborators who provided soil samples from sites including an agricultural location in Spain, alongside colleagues at Luke and the University of Helsinki who collected samples and assisted with laboratory work. The article is open access under a Creative Commons Attribution 4.0 license, making the method immediately available to research groups worldwide.

What comes next is the scientific payoff of having a working measurement. With a validated assay in hand, researchers can now ask how melanin concentrations vary across climate zones, vegetation types, and land-management regimes; whether melanin abundance predicts carbon persistence under warming experiments; and how quickly melanized necromass accumulates or decomposes under different disturbance histories. The method could also help resolve debates about the relative importance of plant-derived versus microbial-derived stable carbon, a question with direct implications for whether soils will continue to function as carbon sinks as the climate changes. Because the authors show that melanin tracks total soil carbon, melanin measurements may eventually serve as a diagnostic indicator of a soil’s capacity for long-term carbon storage.

For a measurement that began as a methodological frustration — two standard assay families failing against the chemical noise of real soil — the outcome is unusually consequential. Soil carbon science has spent decades refining its understanding of plant inputs, mineral associations, and aggregate protection, but the fungal contribution has remained partly hidden behind indirect proxies. By making fungal melanin directly countable in soil, Adamczyk and Adamczyk have converted a long-standing hypothesis into an empirically tractable research program, and their strong correlation between melanin and total soil carbon offers the first direct quantitative support for the idea that the dark pigments of dead fungi are among the quiet architects of Earth’s largest terrestrial carbon reservoir.

Subject of Research: A liquid chromatography method for quantifying fungal melanin in soil and its relationship to soil carbon stabilization

Article Title: A method quantifying soil melanin to understand fungal impacts on soil carbon stability

Article References: Adamczyk, S., & Adamczyk, B. (2026). A method quantifying soil melanin to understand fungal impacts on soil carbon stability. Nature Communications. https://doi.org/10.1038/s41467-026-78616-4

Image Credits: AI Generated

DOI: 10.1038/s41467-026-78616-4

Keywords: soil carbon, fungal melanin, soil organic matter, fungal necromass, liquid chromatography, carbon stabilization, soil microbiology, carbon cycle, analytical chemistry, Nature Communications, soil science, melanized fungi

The study addresses a persistent puzzle in carbon cycle science. Soil organic carbon is a major component of terrestrial carbon stocks, yet how climate, soil properties, and biotic communities jointly regulate it along elevational gradients has remained unclear. Mountains are natural laboratories for this question because they compress enormous environmental variation into short distances: temperature, moisture, soil chemistry, and vegetation all shift as one climbs a slope. By sampling along nearly 3,000 vertical meters, the researchers could observe how each of these variables rises, falls, and interacts without needing to compare sites scattered across continents.

One of the study’s most striking results is that soil organic carbon did not simply increase or decrease with elevation. Instead, it varied nonlinearly, peaking at around 2,017 meters. Plant diversity mirrored this pattern almost exactly, tracking the same mid-elevation peak. Bacterial and fungal diversity, by contrast, peaked at intermediate elevations in a pattern that did not align as tightly with the carbon maximum. This mismatch matters, because it hints from the outset that the belowground communities so often assumed to govern soil carbon may not be the primary drivers of where carbon accumulates on a mountainside.

When the team examined community composition, all three groups of organisms, plants, bacteria, and fungi, differed significantly along the gradient. But the mechanisms assembling those communities turned out to be strikingly different. Plant communities were primarily shaped by environmental filtering, meaning that only species suited to the local climate and soil conditions survive at each elevation. Bacterial communities were structured mainly by geographic distance, consistent with dispersal limitation shaping which microbes are present where. Fungal communities were governed by soil moisture, nutrients, and pH. These divergent assembly rules underscore that plants and microbes respond to fundamentally different filters, which helps explain why their diversity patterns decouple from one another along the slope.

The statistical core of the study lies in its path analysis, a technique that allows researchers to disentangle direct and indirect effects among interacting variables. The analysis revealed that climate was negatively associated with both soil properties and plant diversity, while plant diversity was positively associated with aboveground net primary productivity, or ANPP. ANPP, in turn, showed the strongest positive direct association with soil organic carbon of any pathway in the model. In other words, the chain runs from climate through plant diversity through productivity to soil carbon, with plant diversity emerging as the dominant biotic factor associated with carbon accumulation.

Perhaps the most provocative conclusion is what the analysis did not find. Microbial diversity showed no significant direct effect on soil organic carbon, and neither did its interaction with plant diversity. This challenges a prevailing view in soil science that microbial diversity dominates the regulation of soil carbon. That view has gained traction in recent years, driven in part by growing recognition that microbial necromass, the residual cell material of dead microbes, contributes substantially to stable soil organic matter, and that microbial carbon use efficiency strongly influences how much carbon is retained in soils globally. The Tianshan results do not deny that microbes process carbon, but they suggest that, at least along this elevational gradient, the amount of carbon entering the soil through plant productivity matters more than the diversity of the organisms doing the processing.

The productivity pathway makes mechanistic sense. Diverse plant communities tend to produce more biomass because different species exploit different resources, occupy different niches, and complement one another in capturing light, water, and nutrients. More biomass means more litter, more roots, and more root exudates, all of which are the raw inputs from which soil organic carbon is built. Previous work has shown that plant diversity increases soil microbial activity and soil carbon storage, and that the positive effect of plant diversity on soil carbon depends on climate. The new study extends this logic to a mountain gradient, showing that the diversity-productivity-carbon chain holds across a wide range of climatic conditions within a single landscape.

The implications for grassland management and climate policy could be significant. Grassland soil carbon sequestration is widely regarded as a nature-based climate solution, and estimates of its potential often hinge on assumptions about which factors can be manipulated to increase carbon inputs. If plant diversity is the dominant biotic lever, then restoring diverse plant communities, whether through reseeding, grazing management, or protection from degradation, may be a more reliable route to carbon gains than interventions targeting microbial communities directly. The study also highlights the special importance of mid-elevation zones, where both plant diversity and soil carbon peak, suggesting these elevational belts deserve particular attention in conservation and restoration planning.

There are, of course, caveats. The study examined relationships across an elevational gradient at a single point in time, so it identifies associations rather than experimentally proven causal chains. The authors note that their findings support an indirect, productivity-mediated pathway linking plant diversity to soil carbon accumulation, and the path analysis framework is designed to evaluate such pathways rigorously, but long-term manipulative experiments would be needed to confirm that increasing plant diversity directly causes soil carbon gains under all the climatic conditions represented along the slope. It also remains to be seen whether the pattern holds in other mountain systems, in forests, or in agricultural landscapes, where management histories and plant communities differ profoundly from natural grasslands.

Even with those caveats, the study adds an important piece to one of the biggest puzzles in Earth system science: predicting how soils will store or release carbon as the climate changes. Climate models increasingly recognize that soil carbon responses depend on the interplay between plant inputs, microbial processing, and environmental conditions, yet the relative weights of these factors remain contested. By showing that plant diversity can dominate over microbial diversity as a biotic correlate of soil carbon along a nearly 3,000-meter gradient, the Tianshan study argues for keeping plants at the center of the soil carbon conversation. For a field that has spent much of the past decade looking downward, into the lives of bacteria and fungi, the message from the mountains is to look up as well, at the diversity of the vegetation that feeds the entire belowground economy.

Subject of Research: Plant diversity effects on soil organic carbon sequestration along an elevational gradient in Tianshan Mountain grasslands

Article Title: Plant diversity promotes soil carbon sequestration via productivity pathways along elevational gradients

Article References: Zhang, Y., Zhou, X., Yan, K., Liu, J., Xin, H., Gong, L., & Li, C. (2026). Plant diversity promotes soil carbon sequestration via productivity pathways along elevational gradients. Plant and Soil. https://doi.org/10.1007/s11104-026-09093-3

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09093-3

Keywords: soil organic carbon, plant diversity, elevational gradient, grassland, microbial communities, primary productivity, carbon sequestration, Tianshan Mountains, soil science, biogeography, path analysis, climate

The stakes could hardly be higher. Northern circumpolar permafrost holds roughly 1,000 petagrams of carbon in its first three meters, about half of all the soil carbon stored in every other terrestrial ecosystem on Earth combined. Models estimate that carbon dioxide and methane released from Arctic soils could add between 55 and 230 petagrams of carbon in CO2-equivalent terms to the atmosphere by 2100, a quantity comparable to the emissions of industrialized nations. Yet most of these projections rest on gradual thawing, the slow deepening of the seasonally thawed active layer. What happens during abrupt thaw, when the ground itself collapses, remains far less constrained, even though existing simulations suggest thermokarst terrain could deliver a climate feedback similar in magnitude to gradual thaw emissions.

At Cape Bounty, the team examined two contrasting types of hillslope thermokarst. The first is an active layer detachment, a one-time landslide in which the thawed surface layer slides downslope over tens of meters, exposing a shallow headwall. The second is a retrogressive thaw slump, a feature that keeps growing year after year as frozen deposits thaw and ground ice melts at its headwall, which can retreat by tens of meters each summer. The slump sampled in the study was still actively retreating at up to one meter per year when the team visited in August 2018, exposing fresh, previously perennially frozen sediment with every passing season.

The researchers’ central question was deceptively simple: how much of the organic carbon in these exposed sediments is actually locked away by interactions with minerals, and how much is sitting free, ready to be devoured by microbes once thaw releases it? In soils, organic matter can be stabilized in several ways. Plant fragments unattached to minerals decay quickly. Carbon trapped inside soil aggregates gains physical protection lasting decades to a century. Carbon can also form cation bridges with negatively charged clay surfaces, or bind into organo-metallic complexes with metals such as iron, aluminum, manganese and calcium, or adsorb onto poorly crystalline iron oxides, some of the most effective mineral sorbents for dissolved organic carbon. These chemical associations can preserve carbon for hundreds to thousands of years under stable conditions.

To disentangle these mechanisms, the team combined an unusually broad analytical toolkit. X-ray diffraction characterized the crystalline mineralogy of the sediments, which proved remarkably similar across all profiles, dominated by quartz, feldspars, micas and secondary clays such as kaolinite, illite, vermiculite and chlorite. Portable X-ray fluorescence, calibrated against inductively coupled plasma optical emission spectrometry, quantified total iron, aluminum, manganese, calcium and potassium. Sodium pyrophosphate extraction targeted organo-metallic complexes, ammonium oxalate extraction targeted poorly crystalline oxides, and a two-stage aggregate and density fractionation protocol, using wet sieving and heavy liquid separation with sodium polytungstate, separated free particulate organic matter from mineral-associated carbon.

The results paint a nuanced picture. Chemically stabilized carbon, in the form of small biopolymer fragments bound by chemical bonds, accounts for 13 plus or minus 5 percent of total organic carbon as organo-metallic complexes, and up to 6 plus or minus 2 percent associated with poorly crystalline iron oxides, giving roughly 20 plus or minus 4 percent of total organic carbon chemically bound to minerals or metallic cations. When physical protection of particulate matter in aggregates and larger chemically stabilized molecules is added, the total mineral-protected share rises to 64 plus or minus 10 percent. Aluminum emerged as the dominant metal in complexes and the best predictor of complexed carbon, explaining 89 percent of its variance in the team’s mixed-effect models, ahead of iron and far ahead of manganese.

The most striking finding, however, concerns depth. In the sediments exposed by the actively retreating thaw slump, the proportion of organo-metallic complexes plummets from about 18 percent of total organic carbon in surface samples at 2 to 22 centimeters to a mere 1 percent in the deepest samples at 50 to 70 centimeters. The deep layers are also richer in water-soluble calcium and potassium, with higher electrical conductivity and pH, signatures of sediments that were previously perennially frozen and never underwent meaningful soil development. Because all four profiles share the same mineralogy, the team attributes the pattern not to bedrock differences but to the slump’s retrogressive nature, which guarantees a fresh supply of poorly weathered, weakly protected deep sediment every summer until the feature stabilizes.

This vulnerability matters because thaw slumps are projected to intensify across the Arctic, with terrain susceptible to hillslope thermokarst expanding by roughly 250,000 square kilometers by the end of the century. A first-order mass balance suggests the Cape Bounty slump exposes about 13.5 kilograms of organic carbon per square meter of headwall, versus about 9.8 kilograms for the active layer detachment, and that the slump’s exposed carbon is less mineral-stabilized, at roughly 17.2 percent versus 18.4 percent. In the deepest slump horizon, more than half of the total organic carbon takes the form of free particulate organic carbon, the pool most readily accessible to microbial degradation. Comparable studies at the Peel Plateau in Canada and the Batagay mega-slump in Siberia found the same shallow-to-deep decline in chemically protected carbon, reinforcing the conclusion that historical permafrost thaw dynamics are a first-order control on carbon stability.

Context also shapes how much protection minerals can offer in the first place. The roughly 20 percent chemical stabilization measured at Cape Bounty sits at the low end of Arctic values, about half the 43 plus or minus 20 percent reported for comparable thermokarst and Yedoma sediments in Siberia and Canada. The authors point to Cape Bounty’s extreme setting: at nearly 75 degrees north, some 800 to 900 kilometers farther north than the comparison sites, with a polar desert climate averaging minus 14.8 degrees Celsius and under 150 millimeters of precipitation per year. Such cold, dry conditions allow only limited pedological development and few opportunities for mineral-organic bonds to form. Peatland environments, by contrast, show similarly low mineral-bound proportions but for the opposite reason, their abundant carbon simply saturating the available mineral surfaces.

The team is careful to note the limits of the work, which rests on four distinct profiles, and to flag open questions, including the fate of carbon carried downstream in slump debris tongues and the possibility that calcium-mediated stabilization, which their extraction methods could not isolate, adds uncounted protection. They also caution that shifts in pH or redox conditions, for instance from water saturation, could release mineral-bound carbon, although the well-drained, near-neutral terrain of hillslope thermokarst makes such changes less likely at Cape Bounty. Still, the message for climate models is clear. As abrupt thaw carves ever deeper into frozen ground, it is not just the quantity of carbon being exposed that matters, but its armor, and the deepest layers may be arriving in the modern carbon cycle with the least of it.

Subject of Research: Mineral-bound organic carbon stability in permafrost soils exposed by hillslope thermokarst in the Canadian High Arctic

Article Title: Mineral-bound organic carbon exposed by hillslope thermokarst terrain: case study in Cape Bounty, Canadian High Arctic

Article References: Thomas, M., Fouché, J., Titeux, H., Morelle, C., Bemelmans, N., Lafrenière, M. J., Heslop, J. K., & Opfergelt, S. (2026). Mineral-bound organic carbon exposed by hillslope thermokarst terrain: case study in Cape Bounty, Canadian High Arctic. SOIL, 12(1), 633-664. https://doi.org/10.5194/soil-12-633-2026

Image Credits: AI Generated

DOI: 10.5194/soil-12-633-2026

Keywords: permafrost, thermokarst, organic carbon, soil science, Arctic, retrogressive thaw slump, active layer detachment, organo-mineral interactions, iron oxides, climate feedback, Cape Bounty, greenhouse gases

The story begins with a landmark paper by researchers at the Brazilian Agricultural Research Corporation, EMBRAPA, who used computed tomographic scanning to conduct static and dynamic three-dimensional studies of water in soil. That 1985 study, which has since accumulated 100 citations, marked the first application of the technique in Brazil and established a temporal benchmark against which all subsequent work can be measured. In those early decades, most Brazilian studies relied on non-commercial scanners built in-house, because acquiring radioactive sources for gamma-ray tomography was considerably cheaper than purchasing X-ray systems. First-generation equipment meant long acquisition times and millimeter-scale resolution, and between 1987 and 1993 only a single article using the technique appeared in journals indexed in the Web of Science. Much of the early output circulated in Portuguese-language bulletins, conference proceedings, and regional journals that remained largely invisible to the international community.

The turning point came in the early 2000s, when the number of indexed publications began a steady climb. The review identified a strong linear correlation between time and publication volume, with a correlation coefficient of 0.81, and several recent years produced ten or more articles apiece. The year 2025 set the record with thirteen publications, a signal that the field is currently undergoing rapid expansion. Over the full forty-year period, the 134 articles selected for detailed analysis accumulated 2,596 citations, averaging roughly nineteen citations per article. Citation peaks in 2005, 2011, 2017, and 2019 trace the growing influence of Brazilian work, with the late-2010s surge reflecting an accelerated rate of knowledge adoption and a larger, more active research network than in any previous era.

To build this picture, the authors searched the Web of Science Core Collection using keywords combining tomography, soil, and Brazil, retrieving 265 raw records. After removing one record with a date discrepancy and applying a rigorous two-stage screening process, they retained 134 studies for comprehensive analysis. The screening excluded work relying on other imaging techniques such as electrical resistivity tomography or nuclear magnetic resonance, studies focused on rocks, sediments, or construction materials, and papers lacking sufficient technical detail on tomography workflows. The methodological care extended to open-access classification: automated metadata were manually verified against publisher websites to confirm license structures, guarding against temporal shifts in journal policies. The result is one of the most transparent accounts of a national research field’s development available in the soil science literature.

The quality indicators that emerged from the analysis are remarkable for a field built largely on public funding from a middle-income country. Of the fifty unique journals represented, sixty percent fall into the first or second quartile of the Journal Citation Reports, and the same proportion holds when measured by total article volume. Elsevier published the majority of the articles, fifty-seven of the 134, and Elsevier journals also captured sixty-three percent of all citations. Soil and Tillage Research led all venues with nineteen percent of publications, followed by Applied Radiation and Isotopes, Revista Brasileira de Ciência do Solo, Geoderma, Agriculture-Basel, and the International Journal of Geomechanics. Access models were nearly evenly split: among the 107 articles with verified access metadata, fifty-one percent appeared under open-access licenses of various colors, while forty-nine percent remained subscription-based, a balance the authors interpret as a transitional phase in scientific publishing.

Behind these numbers lies a distinctive institutional and financial structure. Public universities and agricultural research organizations produced the vast majority of the work, and two federal agencies anchored the funding landscape: the National Council for Scientific and Technological Development, CNPQ, provided thirty percent of reported funding, while CAPES, which supports graduate scholarships and negotiates national journal-access agreements, contributed twenty percent. State foundations such as FAPESP, the research company EMBRAPA, and international partners including the United Kingdom’s BBSRC filled out a multi-level funding architecture. Notably, ninety-six percent of the articles were published in English, underscoring a deliberate orientation toward international visibility, though the authors caution that the scarcity of Portuguese-language publications may limit accessibility for local stakeholders such as farmers and regional policymakers.

International collaboration emerged as a defining feature of the field’s most influential work. While seventy-six percent of articles were authored solely by Brazilian researchers, co-authorship with scientists in Canada, the United States, the United Kingdom, China, Italy, and Germany appeared disproportionately among the most-cited papers. A co-authorship network analysis built with VOSviewer revealed a highly interconnected structure organized into distinct clusters: a historical pioneering cluster anchored by early developers such as Crestana, Cruvinel, and Cesareo, and central consolidation hubs involving researchers like Pires, Cássaro, Cooper, and Reichardt, alongside international collaborators including Mooney, Ghanbarian, and Heck. The network reflects decades of academic mentorship, researcher exchange, and multi-institutional partnership, and it documents the emergence of a new generation of Brazilian soil scientists carrying the technique forward.

Perhaps the most consequential applications of the technology concern Brazil’s vast Oxisols, the highly weathered tropical soils that cover roughly forty percent of the country’s agricultural land. Landmark studies quantified how long-term no-tillage systems preserve functional macropore continuity compared with intensive tillage. One influential analysis showed that no-tillage maintains a tri-modal pore size distribution across surface and subsurface layers, driven by complex pore shapes and enhanced connectivity, whereas intensively tilled soil was dominated by isolated, round-shaped pores. A complementary long-term trial found that no-tillage yielded macroporosity of 19.7 percent with superior pore-network connectivity and lower tortuosity, against 14.3 percent under intensive tillage, with a single continuous complex pore network accounting for ninety-seven percent of total macroporosity. These three-dimensional metrics carry direct implications for water infiltration, root growth, and the resilience of tropical agriculture under increasingly extreme moisture events.

The review also mapped the field’s alignment with the United Nations Sustainable Development Goals, using Clarivate’s automated classification scheme. Across 278 SDG occurrences in the corpus, climate action dominated with thirty-two percent, followed by zero hunger at twenty-three percent, life below water at twenty-two percent, and life on land at twenty-one percent. The strong showing of aquatic ecosystem goals reflects how soil processes such as nutrient leaching and sediment transport propagate downstream. The disciplinary spread is equally telling: agriculture leads with seventy-four articles, but physics, engineering, computer science, and chemistry all contribute substantially, and recent work increasingly integrates machine learning and deep learning for pore segmentation, neural-network-based contour identification, and synchrotron-based imaging of phosphorus transport and soil structural change.

Challenges remain, and the authors are candid about them. Access to high-resolution CT equipment and synchrotron facilities is still restricted to a limited number of research centers, and equipment cost, maintenance demands, and the need for specialized image-processing expertise continue to bottleneck broader adoption. The dedicated CT beamline at Brazil’s Sirius synchrotron light source, focused on agronomic studies, represents a major step toward democratizing access. Looking ahead, the review calls for standardized image acquisition and segmentation protocols, open databases of raw CT images and metadata to enable benchmarking and artificial intelligence applications, and deeper integration of tomography with process-based modeling. If those recommendations take hold, the next chapter of Brazilian soil tomography may prove even more transformative than the first four decades, positioning the country’s researchers at the forefront of global efforts to understand, protect, and sustainably manage the ground beneath our feet.

Subject of Research: Bibliometric review of four decades of gamma-ray and X-ray computed tomography research in Brazilian soil science

Article Title: Methodological evolution and global scientific impact of Brazilian soil computed tomography research

Article References: Gaspareto, J. V., & Pires, L. F. (2026). Methodological evolution and global scientific impact of Brazilian soil computed tomography research. Discover Soil, 3(1), Article 183. https://doi.org/10.1007/s44378-026-00340-8

Image Credits: AI Generated

DOI: 10.1007/s44378-026-00340-8

Keywords: computed tomography, soil science, X-ray microtomography, Brazil, soil pore architecture, synchrotron radiation, bibliometrics, no-tillage, Oxisols, sustainable agriculture, soil physics, sustainable development goals

The research team, led by Mengyuan Chang and Zongxing Wang of Zhejiang A&F University, took advantage of an extraordinary natural experiment: a chronosequence of Torreya grandis stands ranging from 100 to 1,600 years old. Because the trees in each age group grow under broadly similar climate and management traditions, differences among the groups can be attributed largely to age itself. The researchers sampled the full leaf-litter-soil continuum, measuring concentrations of carbon, nitrogen, phosphorus, and potassium in green leaves, fallen litter, and soil at two depths, and then calculated how efficiently the trees resorbed each nutrient before leaf drop.

The soil results told a story of slow but relentless change. Organic carbon and total nitrogen in the soil actually increased as stands aged, a pattern consistent with centuries of litter accumulation and organic matter buildup. Total phosphorus remained relatively stable across all age groups in both the 0-10 and 10-20 centimeter layers. But potassium broke the pattern dramatically: soil total potassium declined consistently with tree age, signaling what the authors describe as progressive potassium depletion. In other words, the very nutrient that plants need in large quantities for enzyme activation, stomatal regulation, and stress tolerance was steadily draining away from the system over the centuries.

The trees themselves reflected this depletion. Leaf concentrations of carbon, nitrogen, and potassium all decreased with tree age, while leaf phosphorus held comparatively steady. This divergence matters because leaf chemistry is a sensitive indicator of what a tree can actually extract from its environment. A falling leaf potassium concentration in the oldest stands suggests that the trees were no longer able to take up enough of the element to maintain the internal concentrations seen in their younger counterparts, even as they continued to photosynthesize and grow on the accumulated organic capital of their soils.

Perhaps the most striking result concerned nutrient resorption efficiency, the process by which trees withdraw valuable nutrients from senescing leaves before they fall, effectively recycling their own biochemical investments. Resorption efficiencies of nitrogen, phosphorus, and potassium all declined substantially as tree age increased, but potassium resorption showed by far the largest drop, plummeting from about 75 percent in the youngest stands to just 32 percent in the oldest. For a tree, losing the ability to salvage three-quarters of the potassium in its leaves before abscission represents a fundamental shift in nutrient economy, forcing greater dependence on an increasingly depleted soil pool.

The drivers behind these shifts were traced through statistical modeling of soil chemistry. Nitrogen resorption efficiency responded primarily to soil nitrogen availability, specifically the concentrations of nitrate and ammonium, the two inorganic forms plants can absorb directly. Phosphorus and potassium resorption, by contrast, were more sensitive to soil potassium levels and pH. This dissociation suggests that different nutrients are governed by different environmental levers, and that a one-size-fits-all fertilization strategy would fail to address the specific bottlenecks emerging in ancient stands.

To integrate these relationships, the team employed structural equation modeling, a technique that allows researchers to test networks of hypothesized cause-and-effect pathways simultaneously. The analysis revealed that tree age influences nutrient resorption efficiency primarily indirectly, through its effects on soil nutrient stoichiometry and on the stoichiometry of leaves and litter. Crucially, potassium-related imbalances exerted the most negative influence on resorption efficiency of any factor examined. The implication is that potassium is not merely one nutrient among several running low; it acts as a keystone element whose scarcity destabilizes the balance of nitrogen and phosphorus cycling throughout the ecosystem.

This finding resonates with a growing body of global evidence. A 2023 meta-analysis cited in the study highlighted that potassium limitation is far more widespread in terrestrial ecosystems than classical nutrient-paradigm thinking, which has long focused on nitrogen and phosphorus, would suggest. Potassium is unusual among macronutrients because it does not form part of any organic structural compound; it exists in plant tissue as a free ion, which means it is easily leached from litter and soils and cannot be locked into stable organic pools the way nitrogen and phosphorus can. Over sixteen centuries of continuous cultivation and harvest, that mobility appears to have worked against the ancient Torreya stands.

The study also touches on the concept of stoichiometric homeostasis, the ability of organisms to maintain stable internal elemental ratios despite variation in what their environment supplies. As the ancient trees aged, their capacity to buffer against shifting soil chemistry appears to have weakened, leaving them increasingly exposed to the elemental imbalances developing around their roots. Combined with the region’s history of high atmospheric nitrogen deposition, which earlier work on Torreya plantations suggested can blunt the benefits of conventional fertilization, the picture that emerges is one of multiple nutrient stresses compounding one another in the oldest stands.

For conservationists, the practical implications are concrete. The authors argue that soil test-based nutrient management, including targeted potassium fertilization and measures to prevent soil acidification, could help sustain the ancient Torreya grandis forests, which are both culturally treasured and economically important for their edible nuts. More broadly, the study underscores that ancient trees are not simply younger trees scaled up in time; they occupy a distinct biogeochemical state shaped by centuries of nutrient cycling, and protecting them may require understanding and correcting elemental deficits that only become visible across millennial timescales. As the world’s oldest living trees face mounting pressures from climate change and land-use intensification, this research suggests that what lies beneath them, in the slow chemistry of their soils, may matter as much as what threatens them above ground.

Subject of Research: Long-term soil potassium depletion and nutrient resorption dynamics in millennial-aged Torreya grandis forests

Article Title: Potassium depletion and reduced nitrogen resorption intensifies the nutrient constraints in millennial-aged Torreya grandis forests

Article References: Chang, M., Wang, Z., Fan, Y., Jin, S., & Xie, H. (2026). Potassium depletion and reduced nitrogen resorption intensifies the nutrient constraints in millennial-aged Torreya grandis forests. Plant and Soil. https://doi.org/10.1007/s11104-026-09116-z

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09116-z

Keywords: Torreya grandis, potassium depletion, nutrient resorption, ecological stoichiometry, ancient trees, chronosequence, soil science, forest ecology, stoichiometric homeostasis, leaf-litter-soil continuum, nitrogen cycling, soil acidification

The research team, led by Arshdeep Singh Atwal and Aarush Lal of CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur, focused on cauliflower, a nutrient-hungry cool-season crop that dominates the vegetable economy of the Shivalik foothill zone. Indora block, spanning roughly 298 square kilometres between elevations of 261 and 765 metres, receives about 1000 millimetres of rain annually and enjoys a semi-humid subtropical climate that has made it an important vegetable belt. Yet the region’s agriculture is constrained by tiny landholdings, erratic water availability, and fertiliser use that is often both low and imbalanced. Continuous cropping, excessive tillage, residue removal and skewed fertiliser regimes have accelerated nutrient mining and organic matter depletion, making systematic soil characterisation an urgent priority rather than an academic luxury.

Between August 2022 and 2023, the researchers sampled the top 20 centimetres of soil from ninety-nine farming households growing the Megha cauliflower variety on plots of at least 500 square metres, covering twenty-two village councils and thirty-seven villages. The samples, air-dried and sieved, were subjected to a full battery of standard analyses: bulk density by core sampler, texture by hydrometer, water holding capacity by the Keen and Raczkowski box method, pH by glass electrode, organic carbon by dichromate wet oxidation, available nitrogen by alkaline potassium permanganate, phosphorus by Olsen’s method, potassium by flame photometry, and sulphur by turbidimetry, alongside exchangeable calcium and magnesium. The result was one of the most comprehensive physico-chemical datasets ever assembled for this corner of the lower Himalayas.

The descriptive statistics painted a picture of generally healthy but unevenly distributed fertility. Soil pH ranged from 6.34 to 7.56 with a mean of 7.16, placing the soils in the neutral to slightly alkaline range that suits vegetable production well. Electrical conductivity, averaging 0.26 decisiemens per metre, stayed safely below the 0.8 threshold considered problematic for crops. Organic carbon ranged from 7.00 to 13.60 grams per kilogram, a medium-to-high level the authors attribute to the regular addition of farmyard manure and plant residues by local growers. Available nitrogen averaged 284 kilograms per hectare, phosphorus a modest 12.15 kilograms per hectare, and potassium 280 kilograms per hectare, while sulphur, calcium and magnesium varied considerably, with phosphorus showing the highest relative variability of all measured properties at a coefficient of variation of 38.28 percent.

Correlation analysis revealed the web of interdependencies that governs how these soils behave. Bulk density, a measure of compaction, correlated positively with particle density and available potassium, the latter likely reflecting potassium-bearing minerals such as feldspars and micas that simultaneously increase particle packing and nutrient supply. It correlated strongly and negatively with porosity, as expected, since denser soils have less pore space. Most strikingly, organic carbon correlated strongly and positively with available nitrogen at 0.65, confirming that organic matter is the engine of nitrogen supply in these systems, releasing mineralisable nitrogen in proportion to its abundance. Sulphur tracked positively with pH, consistent with enhanced mineralisation of organic sulphur under near-neutral conditions, while exchangeable calcium and magnesium rose together with indicators of improved fertility and microbial activity.

To compress this multivariate complexity into interpretable structure, the team applied principal component analysis, which extracted six components with eigenvalues above one that together explained 69.43 percent of the total variance. The first component, dominated by bulk density alone, signalled that soil structural condition, shaped by management decisions about tillage and compaction, is the single strongest axis of differentiation across the landscape. The second was driven by organic carbon, reflecting the heavy reliance of smallholders on organic manure as their primary nutrient pathway. Later components captured particle density with phosphorus and potassium, the pH-sulphur-calcium-magnesium cluster tied to base saturation and leaching dynamics, electrical conductivity, and finally nitrogen with porosity. A complementary hierarchical cluster analysis grouped the ninety-nine sampling sites into seven major clusters, whose long branch linkages pointed to substantial multivariate dissimilarity driven by topography, parent material and divergent management environments.

The study’s most innovative contribution came from spatial statistics. Using Global Moran’s I, a measure of spatial autocorrelation computed in the GeoDa software with a six-nearest-neighbour weight matrix and 999 permutations, the researchers tested whether each soil property was randomly distributed or spatially structured. Six properties passed the significance test: pH, electrical conductivity, organic carbon, porosity, nitrogen and sulphur. Positive Moran’s I values for these attributes mean that similar values cluster together on the map, so high-pH fields neighbour high-pH fields and nitrogen-poor patches form coherent zones rather than isolated points. The remaining properties, including bulk density, water holding capacity, phosphorus, potassium, calcium and magnesium, appeared spatially random, a finding the authors link to the region’s complex topography, which creates microclimatic and edaphic variation over short distances, and to individual farm management decisions that override natural gradients.

Local Indicator of Spatial Association analysis then pinpointed exactly where the clusters lie. Sulphur expressed the strongest clustering of any property, with 47 significant sampling sites and 23.23 percent of the study area falling into the high-high category, concentrated toward the north, a pattern the authors attribute to gypsiferous parent material, higher organic matter and fertilisers such as single superphosphate. Electrical conductivity formed high-value clusters in the north, where erratic and low rainfall allows salts to accumulate, while nitrogen showed high clusters in the central and northern regions and low clusters toward the south-west, a patchiness that implicates nutrient management practices as the dominant driver rather than any natural gradient. The team even notes that naturally occurring Acacia catechu trees, which fix atmospheric nitrogen, may act as local nitrogen hotspots. Porosity was the only variable with more low-low than high-high area, with compacted zones in the northern half pointing to the cumulative effect of seasonal tillage and field traffic.

Translated into practice, the cluster typology becomes a management blueprint. Low-low zones, where a property is significantly depressed and surrounded by similarly depleted neighbours, are the highest-priority targets: nitrogen-poor clusters call for increased fertilisation or green manures such as Sesbania or Trifolium, organic-carbon-poor zones for farmyard manure, compost and legume cover crops between cauliflower seasons, and sulphur-deficient patches for sulphur-coated urea and oilseed cakes. Porosity low-low zones indicate compaction that could be remedied with subsoiling or deep tillage combined with organic amendments. High-high clusters, by contrast, may need optimisation to avoid toxicity-like conditions, while high-low outliers, anomalously enriched sites within deficient neighbourhoods, deserve investigation to understand how they arose. To visualise all of this, the team generated continuous fertility surfaces using inverse distance weighting in QGIS with a weighting power of two and a fine spatial resolution of 0.0001 degrees, producing thematic maps of every measured property clipped to the block boundary.

The authors are candid about the limitations: the survey covered a single block, a single season, and only the surface layer, so the findings cannot be generalised to other agro-climatic zones without further work. Even so, the framework is deliberately replicable, and the maps now serve as a baseline against which future soil health monitoring, climate-driven fertility shifts and the effects of changing nutrient regimes can be measured. For a region where farmers manage fragments of land under unpredictable monsoon rainfall, the message is quietly transformative: soil fertility in the lower Himalayas is not a uniform backdrop but a structured, mappable landscape of hotspots and deficits, and knowing where those zones lie is the first step toward feeding crops precisely what they need, where they need it, while protecting fragile mountain soils for the long term.

Subject of Research: Spatial variability and geostatistical mapping of soil physico-chemical properties in vegetable-cultivated Himalayan soils

Article Title: Spatial characterization and geostatistical analysis of soil properties in vegetable cultivated soils of Indora block (Kangra district), Himachal Pradesh, India

Article References: Atwal, A. S., Lal, A., Kapoor, R., Sandal, S. K., Sharma, R., Sepehya, S., & Kumari, P. (2026). Spatial characterization and geostatistical analysis of soil properties in vegetable cultivated soils of Indora block (Kangra district), Himachal Pradesh, India. Discover Soil, 3(1), Article 116. https://doi.org/10.1007/s44378-026-00271-4

Image Credits: AI Generated

DOI: 10.1007/s44378-026-00271-4

Keywords: soil science, spatial variability, geostatistics, Moran's I, LISA, precision agriculture, Himalayan farming, cauliflower, soil fertility, nutrient management, Himachal Pradesh, organic carbon