Soil Systems

26 pages, 2799 KB

Open AccessArticle

Fingerprinting of Bulk and Water-Extractable Soil Organic Matter of Chernozems Under Different Tillage Practices for Twelve Years: A Case Study

by Yulian Farkhodov, Natalia Danchenko, Igor Danilin, Irina Grigoreva, Natalia Matveeva, Aliia Ziganshina, Nikita Ermolaev, Sergey Yudin, Ivan Nadutkin, Sergey Kambulov and Vladimir Kholodov

Soil Syst. 2025, 9(4), 138; https://doi.org/10.3390/soilsystems9040138 - 15 Dec 2025

Cited by 1 | Viewed by 1161

Abstract

Soil conservation technologies are widely studied for their effects on soil organic carbon (SOC) preservation, yet their impact on the composition of soil organic matter (SOM) remains underinvestigated. This study evaluated the effects of two non-inversion tillage systems, MP and NT, on agro-physical [...] Read more.

Soil conservation technologies are widely studied for their effects on soil organic carbon (SOC) preservation, yet their impact on the composition of soil organic matter (SOM) remains underinvestigated. This study evaluated the effects of two non-inversion tillage systems, MP and NT, on agro-physical and chemical properties and SOM composition (including water-extractable matter) in Haplic Chernozem Pachic. After 12 years, non-inversion tillage showed no significant differences in SOC, WEOC, and soil structure condition compared to MP. Only NT treatment distinctly enhanced the coefficient of soil structuring (K_str) and mean diameter of water-stable aggregates (MWD_WSA), by 1.5 and 2 times, respectively. Differences in SOM composition were clearly pronounced between treatments in the 0–10 cm layer. Non-inversion tillage favored microbial-derived stable SOM, whereas NT enriched SOM with fresh plant material. Our findings revealed that non-inversion tillage shifts the composition of SOM toward recalcitrant components even more than MP due to limited fresh OM input and enhanced mineralization of unprotected SOM during tillage. This poses carbon loss risks. Periodic moldboard plowing may be a way to improve carbon retention in non-inversion tillage, as it allows plant residues to be incorporated into the soil profile and replenish organic matter. Full article

(This article belongs to the Special Issue Land Use and Management on Soil Properties and Processes: 2nd Edition)

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41 pages, 1828 KB

Open AccessReview

Phytoremediation of Co-Contaminated Environments: A Review of Microplastic and Heavy Metal/Organic Pollutant Interactions and Plant-Based Removal Approaches

by Pavlos Tziourrou and Evangelia E. Golia

Soil Syst. 2025, 9(4), 137; https://doi.org/10.3390/soilsystems9040137 - 15 Dec 2025

Cited by 5 | Viewed by 3754

Abstract

The increasing presence of microplastics (MPs) in terrestrial ecosystems, particularly when combined with organic pollutants and heavy metals, presents a considerable environmental challenge. This review examines the intricate interactions between MPs, co-contaminants (both organic and inorganic), and plants involved in phytoremediation processes. A [...] Read more.

The increasing presence of microplastics (MPs) in terrestrial ecosystems, particularly when combined with organic pollutants and heavy metals, presents a considerable environmental challenge. This review examines the intricate interactions between MPs, co-contaminants (both organic and inorganic), and plants involved in phytoremediation processes. A literature search was performed across the databases Scopus, ScienceDirect, and Google Scholar, covering the timeframe from 2015 to 2025. The studies selected specifically addressed the synergistic and antagonistic effects of microplastics in conjunction with heavy metals or organic pollutants (such as PAHs and pesticides) within plant–soil systems. The findings reveal that MPs influence pollutant mobility, bioavailability, and toxicity through adsorption and desorption mechanisms, leading to varied implications for plant growth, microbial communities, and contaminant uptake. Depending on the physicochemical characteristics of MPs and co-pollutants, the effects can range from increased phytotoxicity to diminished contaminant accumulation in plants. Additionally, physiological and molecular disruptions, including oxidative stress, hormonal imbalances, and impaired enzymatic activity, were frequently noted in co-contamination scenarios. Recent developments, such as the creation of genetically modified hyperaccumulator plants and the use of nanotechnology and microbial consortia, demonstrate potential to enhance phytoremediation efficiency in complex polluted soils. This review underscores the pressing need for integrated, multidisciplinary strategies to overcome the limitations of existing phytoremediation methods in co-contaminated environments. Future research should focus on standardized methodologies, a mechanistic understanding, and the safe implementation of emerging biotechnologies for sustainable soil remediation. Full article

(This article belongs to the Special Issue Research on Trace and Hazardous Elements and Emerging Pollutants in Soils and Sediments)

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28 pages, 2494 KB

Open AccessArticle

Heavy Metal Contamination in Homestead Agricultural Soils of Bangladesh: Industrial Influence, Human Exposure and Ecological Risk Assessment

by Afia Sultana, Qingyue Wang, Miho Suzuki, Christian Ebere Enyoh, Md. Sohel Rana, Yugo Isobe and Weiqian Wang

Soil Syst. 2025, 9(4), 136; https://doi.org/10.3390/soilsystems9040136 - 11 Dec 2025

Cited by 6 | Viewed by 2858

Abstract

Heavy metal contamination in agricultural soils poses serious threats to food safety, ecosystem integrity, and public health. This study investigates the concentrations, ecological risks, and human health impacts of nine heavy metals Cr, Mn, Co, Ni, Cu, Zn, Pb, As, and V in [...] Read more.

Heavy metal contamination in agricultural soils poses serious threats to food safety, ecosystem integrity, and public health. This study investigates the concentrations, ecological risks, and human health impacts of nine heavy metals Cr, Mn, Co, Ni, Cu, Zn, Pb, As, and V in homestead agricultural soils collected from two depths, surface (0–20 cm) and subsurface (21–50 cm), across industrial and non-industrial regions of Bangladesh, using inductively coupled plasma mass spectrometry (ICP-MS). Results revealed that surface soils from industrial areas exhibited the highest metal concentrations in order of Mn > Zn > Cr > Pb > V > Ni > Cu > As > Co. However, maximum As levels were detected in non-industrial areas, suggesting combined influences of local geology, intensive pesticide application, and prolonged irrigation with As-contaminated groundwater. Elevated concentrations in surface soils indicate recent contamination with limited downward migration. Multivariate statistical analyses indicated that industrial and urban activities are the major sources of contamination, whereas Mn remains primarily geogenic, controlled by natural soil forming processes. Contamination factor (CF) and pollution load index (PLI) analyses identified Pb and As as the principal pollutants, with hotspots in Nairadi, Majhipara (Savar), Gazipur sadar, and Chorkhai (Mymensingh). Ecological risk (ER) assessment highlighted As and Pb as the dominant environmental stressors, though overall risk remained low. Human health risk analysis showed that ingestion is the primary exposure pathway, with children being more susceptible than adults. Although the hazard index (HI) values were within the acceptable safety limits, the estimated carcinogenic risks for As and Cr exceeded the USEPA thresholds, indicating potential long term health concerns. Therefore, the cumulative carcinogenic risk (CCR) results demonstrate that As is the primary driver of lifetime carcinogenic risk in homestead soils, followed by Cr, while contributions from other metals are minimal. These findings emphasize the urgent need for continuous monitoring, improved industrial waste management, and targeted mitigation strategies to ensure safe food production, a cleaner environment, and better public health. Full article

(This article belongs to the Special Issue Challenges and Future Trends of Soil Ecotoxicology)

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16 pages, 1486 KB

Open AccessArticle

Volatile Organic Compounds from Candelilla-Associated PGPR Enhance Arabidopsis thaliana Seedling Growth Under Salinity Stress

by María Teresa Salazar-Ramírez, Rubén Palacio-Rodríguez, Jesús Josafath Quezada-Rivera, Tania Elizabeth Velásquez-Chávez, Gisela Muro-Pérez, Hortencia Ivone Ortega-Reyes, Jorge Arnaldo Orozco-Vidal, Antonio Gerardo Yescas-Coronado, Gerardo Antonio Verástegui-Hernández and Jorge Sáenz-Mata

Soil Syst. 2025, 9(4), 135; https://doi.org/10.3390/soilsystems9040135 - 10 Dec 2025

Cited by 3 | Viewed by 1372

Abstract

Soil salinity imposes a critical constraint on plant productivity, highlighting the need for sustainable biological strategies to enhance stress tolerance. This study assessed the effects of volatile organic compounds (VOCs) emitted by ten plant-growth-promoting rhizobacteria (PGPR) isolated from the rhizosphere of Euphorbia antisyphilitica [...] Read more.

Soil salinity imposes a critical constraint on plant productivity, highlighting the need for sustainable biological strategies to enhance stress tolerance. This study assessed the effects of volatile organic compounds (VOCs) emitted by ten plant-growth-promoting rhizobacteria (PGPR) isolated from the rhizosphere of Euphorbia antisyphilitica on the growth of Arabidopsis thaliana seedlings exposed to 0, 50, and 100 mM NaCl. A divided Petri dish system was used to quantify biomass, root architecture, proline accumulation, sodium content, and chlorophyll concentration. Three strains—Siccibacter colletis CASEcto12, Enterobacter quasihormaechei NFbEcto18, and Bacillus wiedmannii NFbEndo12—significantly enhanced seedling development under saline and non-saline conditions (p ≤ 0.05). At 50 mM NaCl, S. colletis CASEcto12 increased primary root length from 40.25 to 64.81 mm and fresh weight from 45.05 to 133.33 mg, while E. quasihormaechei NFbEcto18 elevated lateral root number from 10 to 24, compared to the uninoculated control. Under 100 mM NaCl, E. quasihormaechei NFbEcto18 increased proline accumulation (0.564–1.378 mmol g⁻¹ FW) and reduced Na⁺ content (0.146–0.084 mmol g⁻¹ FW), indicating improved osmotic and ionic regulation. VOC profiling using SPME-GC-MS revealed aldehydes, ketones, and alcohols as predominant classes. Overall, these findings demonstrate the potential of candelilla-associated PGPR VOCs as promising biostimulants for enhancing plant performance in salt-affected soils. Full article

(This article belongs to the Topic Microbe-Induced Abiotic Stress Alleviation in Plants)

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17 pages, 3260 KB

Open AccessArticle

Monitoring Soil Biodiversity and Biological Resilience in Disturbed Ecosystems: First Application of the BSR Index

by Giambattista Maria Altieri, Josefina Garrido, Salustiano Mato, Benedicto Soto, Vito Santarcangelo, Giuseppe Bari and Eustachio Tarasco

Soil Syst. 2025, 9(4), 134; https://doi.org/10.3390/soilsystems9040134 - 9 Dec 2025

Viewed by 1131

Abstract

Soil biodiversity is crucial for maintaining biological soil resilience, understood as a temporal property and as the ability of soils to uphold or recover their ecological functions under stress thanks to the diversity and complementarity of their biological communities. To evaluate this property, [...] Read more.

Soil biodiversity is crucial for maintaining biological soil resilience, understood as a temporal property and as the ability of soils to uphold or recover their ecological functions under stress thanks to the diversity and complementarity of their biological communities. To evaluate this property, we developed the Biological Soil Resilience Index (BSR), conceived as an evolution of the QBS-ar approach by integrating additional key bioindicators—entomopathogenic nematodes, entomopathogenic fungi, and earthworms—together with microarthropod eco-morphological adaptation scores. This multi-taxon framework provides a more comprehensive assessment of soil biological conditions than single-group indices and is specifically designed to be applied repeatedly over time to detect resilience trajectories. The Biodiversity Soil Resilience (BSR) Index was applied across nine sites subject to low, medium, and high anthropogenic disturbance, spanning urban, industrial, and airport environments. Results revealed not a resilience gradient but a clear disturbance gradient: low-impact sites achieved the highest BSR values (52–59), reflecting diverse and functionally complementary assemblages; medium-impact sites maintained moderate BSR value (27–42), but displayed imbalances among faunal groups; and high-impact sites showed the lowest values, including a critically low score at C_HI (17.86), where entomopathogens were absent and earthworm populations reduced. Entomopathogenic organisms proved particularly sensitive, disappearing entirely under severe disturbance. The BSR was sensitive to environmental gradients and effective in distinguishing ecologically meaningful differences among soil communities. Because it can be repeatedly applied over time, BSR provides the basis for monitoring long-term resilience dynamics, detecting early warning signals, and support timely mitigation or restoration measures. Overall, the study highlights the pivotal role of biodiversity in sustaining soil resilience and supports the BSR Index as a simple yet integrative tool for soil health assessment and for future resilience monitoring in disturbed landscapes. Full article

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70 pages, 16474 KB

Open AccessArticle

Assessment of the Accuracy of ISRIC and ESDAC Soil Texture Data Compared to the Soil Map of Greece: A Statistical and Spatial Approach to Identify Sources of Differences

by Stylianos Gerontidis, Konstantinos X. Soulis, Alexandros Stavropoulos, Evangelos Nikitakis, Dionissios P. Kalivas, Orestis Kairis, Dimitrios Kopanelis, Xenofon K. Soulis and Stergia Palli-Gravani

Soil Syst. 2025, 9(4), 133; https://doi.org/10.3390/soilsystems9040133 - 25 Nov 2025

Viewed by 3410

Abstract

Soil maps are essential for managing Earth’s resources, but the accuracy of widely used global and pan-European digital soil maps in heterogeneous landscapes remains a critical concern. This study provides a comprehensive evaluation of two prominent datasets, ISRIC-SoilGrids and the European Soil Data [...] Read more.

Soil maps are essential for managing Earth’s resources, but the accuracy of widely used global and pan-European digital soil maps in heterogeneous landscapes remains a critical concern. This study provides a comprehensive evaluation of two prominent datasets, ISRIC-SoilGrids and the European Soil Data Centre (ESDAC), by comparing their soil texture predictions against the detailed Greek National Soil Map, which is based on over 10,000 field samples. The results from statistical and spatial analyses reveal significant discrepancies and weak correlations, with a very low overall accuracy for soil texture class prediction (19–21%) and high Root Mean Square Error (RMSE) values ranging from 13% to 19%. The global models failed to capture local variability, showing very low explanatory power (R² < 0.2) and systematically underrepresenting soils with extreme textures. Furthermore, these prediction errors are not entirely random but are significantly clustered in hot spots linked to distinct parent materials and geomorphological features. Our findings demonstrate that while invaluable for large-scale assessments, the direct application of global soil databases for regional policy or precision agriculture in a geologically complex country like Greece is subject to considerable uncertainty, highlighting the critical need for local calibration and the integration of national datasets to improve the reliability of soil information. Full article

(This article belongs to the Special Issue Use of Modern Statistical Methods in Soil Science)

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18 pages, 1774 KB

Open AccessArticle

Effects of Long-Term Soil Management Under Alfalfa Cultivation on Soil Fertility and Salinity in Arid Agroecosystems of the Ziban Region, Algeria

by Fatima Zohra Batoul Touati, Abdelbasset Boumadda, Fouzi Benbrahim, Abderraouf Benslama and Jose Navarro-Pedreño

Soil Syst. 2025, 9(4), 132; https://doi.org/10.3390/soilsystems9040132 - 20 Nov 2025

Viewed by 2241

Abstract

In arid regions, the soil degradation from salinization, low organic matter content, and compaction severely limits agricultural productivity. Leguminous perennials such as alfalfa (Medicago sativa L.) have the potential to restore soil quality, but their long-term effects remain underexplored in North African [...] Read more.

In arid regions, the soil degradation from salinization, low organic matter content, and compaction severely limits agricultural productivity. Leguminous perennials such as alfalfa (Medicago sativa L.) have the potential to restore soil quality, but their long-term effects remain underexplored in North African drylands. This study aimed to evaluate the impacts of long-term (7–8 years) alfalfa cultivation on soil fertility and salinity in the Ziban region of Algeria. Ninety topsoil samples (0–30 cm) from cultivated and adjacent uncultivated plots were collected and analyzed, determining organic matter (OM), soil organic carbon (SOC), soil nitrogen stock (SNS), electrical conductivity (EC), sodium adsorption ratio (SAR), pH, major cations (Ca²⁺, Mg²⁺, Na⁺), sulfate (SO₄²⁻), bulk density (BD), and texture. Compared with uncultivated soils, alfalfa cultivation increased OM by 82.26%, SOC by 78.38%, and SNS by 102.99%, while reducing EC by 40.36%, SAR by 28.94% and BD by 6.16% (p < 0.05), indicating significant improvements in fertility, structure and reductions in sodicity. PCA revealed distinct gradients separating fertility–salinity parameters from compaction–sodicity in cultivated and uncultivated soils. These results confirm that alfalfa systems enhance nutrient cycling, reduce salt stress, and improve structural stability in arid agroecosystems through reduced bulk density and increased organic matter in arid agroecosystems. Integrating alfalfa into land management strategies could promote sustainable restoration of degraded soils in drylands. Further research should optimize irrigation and organic inputs to maximize these benefits under climate-stress conditions. Full article

(This article belongs to the Special Issue Integrated Soil Management: Food Supply, Environmental Impacts, and Socioeconomic Functions: 2nd Edition)

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17 pages, 2795 KB

Open AccessArticle

Soil Properties Governing Erodibility of Cuban Soils: A Univariate Erodibility Equation

by Gustavo R. Alonso, Javier Casalí, Miguel Ángel Campo-Bescós and Jorge Díaz

Soil Syst. 2025, 9(4), 131; https://doi.org/10.3390/soilsystems9040131 - 19 Nov 2025

Viewed by 1280

Abstract

Accelerated water erosion is a major soil degradation process that affects soil and water quality. In Cuba, specifically, more than 40% of agricultural lands are affected by severe erosion problems. Estimating accurate erodibility values is a crucial step for the calibration and proper [...] Read more.

Accelerated water erosion is a major soil degradation process that affects soil and water quality. In Cuba, specifically, more than 40% of agricultural lands are affected by severe erosion problems. Estimating accurate erodibility values is a crucial step for the calibration and proper application of erosion models. Several equations have been developed to estimate erodibility from soil properties; however, these are often soil- or site-specific, limiting their application. This study aims to (1) identify soil properties governing the erodibility of tropical soils from western Cuba, (2) find suitable regression models to estimate erodibility from these properties, and (3) test widely applied erodibility equations. To achieve these goals, rainfall simulation experiments were conducted on runoff plots, and erosion-related physical, chemical, and mechanical soil properties were determined for 19 different soils. The main results indicated that good correlations between erodibility and certain soil properties were achieved after clustering soils based on their cation exchange capacity (CEC) values and clay content. Soils characterized by more than 30% of clay and 40 cmol+ kg⁻¹ of CEC were excluded from the main analysis. Generally, clay content controls the erodibility of these tropical soils, exhibiting an inverse relationship. However, in the excluded soils, the clay fraction showed a positive relationship with erodibility. Soil water retention at the lowest matric potentials demonstrated the strongest correlation with soil erodibility, as this variable encompasses compound information related to clay, mineralogy, and organic matter. A new regression model to estimate erodibility based solely on the volumetric water content at 1500 kPa is presented. The optimal fitted logarithmic model accounts for 64% of the predictand variability in the studied soils. When testing known erodibility models, the nomograph was found to best mimic the erodibility trend of these soils, although it exhibited marked uncertainty and underestimation biases. Full article

(This article belongs to the Special Issue Soil Erosion, Mass Movements and Pedoclimatic Disequilibrium in Aggradational Landforms)

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22 pages, 2136 KB

Open AccessArticle

Washing Procedure with Several Reagents for Ecological Rehabilitation of Soil Polluted with Heavy Metals

by Ioana Monica Sur, Vasile Calin Prodan, Valer Micle, Mircea Nasui, Andreea Hegyi, Veronica Simona Pop and Liviu Iacob Scurtu

Soil Syst. 2025, 9(4), 130; https://doi.org/10.3390/soilsystems9040130 - 16 Nov 2025

Cited by 5 | Viewed by 1478

Abstract

Soil contamination by heavy metals poses serious risks to human health and the environment. This study investigates the removal of Pb, Cu, Zn, Cd, and Cr from heavily contaminated slightly acidic to neutral soil (pH 6.5) using organic washing agents (humus, malic acid, [...] Read more.

Soil contamination by heavy metals poses serious risks to human health and the environment. This study investigates the removal of Pb, Cu, Zn, Cd, and Cr from heavily contaminated slightly acidic to neutral soil (pH 6.5) using organic washing agents (humus, malic acid, and gluconic acid) at concentrations of 1% and 3% and a solid-to-liquid ratio (S/L) of 1:8. The results reveal that metal mobilization depends strongly on the type and concentration of the extraction agent, the target metal, and soil properties. Cd was highly mobilized, reaching more than 90% with 3% gluconic acid, whereas Cu and Pb remained largely immobile (<3%), and Cr (40–78%) and Zn (8–26%) showed intermediate extraction. This study establishes a clear hierarchy of metal mobility (Cd > Cr > Zn > Cu ≈ Pb) and demonstrates that metal speciation, soil chemistry, pH, and S/L ratio critically govern extraction efficiency. These findings provide mechanistic insights into metal–ligand interactions and practical guidance for optimizing soil remediation strategies using organic acids. Full article

(This article belongs to the Special Issue Research on Trace and Hazardous Elements and Emerging Pollutants in Soils and Sediments)

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14 pages, 4470 KB

Open AccessArticle

Fungi and Potentially Toxic Elements (PTEs): Exploring Mycobiota in Serpentinite Soils

by Laura Canonica, Grazia Cecchi, Sebastiano Comba, Simone Di Piazza, Fedra Gianoglio, Pietro Marescotti, Samuele Voyron and Mirca Zotti

Soil Syst. 2025, 9(4), 129; https://doi.org/10.3390/soilsystems9040129 - 14 Nov 2025

Viewed by 1063

Abstract

Serpentinite soils represent extreme environments characterized by deficiencies in essential nutrients (Ca, K, P, N), an unfavorable Ca/Mg ratio, low water retention, and elevated concentrations of several geogenic potentially toxic elements (PTEs). In particular, the study site, located in Sassello (Liguria, Italy) within [...] Read more.

Serpentinite soils represent extreme environments characterized by deficiencies in essential nutrients (Ca, K, P, N), an unfavorable Ca/Mg ratio, low water retention, and elevated concentrations of several geogenic potentially toxic elements (PTEs). In particular, the study site, located in Sassello (Liguria, Italy) within the serpentinites of the High-Pressure–Low-Temperature (HP–LT) metaophiolites of the Voltri Massif, exhibited concentrations of chromium, nickel and cobalt exceeding Italian legal thresholds by up to one order of magnitude. This study aimed to assess fungal diversity and to isolate culturable strains naturally adapted to these challenging conditions for potential use in bioremediation. Culturable-dependent analyses allowed for the isolation of viable fungal strains, with Penicillium (52%), Umbelopsis (17.9%), and Aspergillus (11.6%) found as dominant genera. Additionally, metabarcoding analyses provided a broader view of fungal community composition, revealing the presence and distribution of both culturable and non-culturable taxa. The combined approach highlighted the richness of the serpentinite soil mycobiota and its role as a reservoir of PTE-resistant organisms. These findings offer new insights into the ecology of metal-rich soils and identify promising candidates for sustainable remediation strategies in PTE-contaminated environments. Full article

(This article belongs to the Special Issue Research on Trace and Hazardous Elements and Emerging Pollutants in Soils and Sediments)

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22 pages, 1902 KB

Open AccessArticle

Soil De-Sealing and Recycled Aggregates Application: One Year of Monitoring

by Gaia Mascetti, Roberto Comolli, Francesca Pittino, Isabella Gandolfi and Chiara Ferré

Soil Syst. 2025, 9(4), 128; https://doi.org/10.3390/soilsystems9040128 - 14 Nov 2025

Cited by 1 | Viewed by 1443

Abstract

De-sealing, or depaving, is increasingly adopted to restore soil permeability and support green infrastructure, yet its potential to recover soil functions remains insufficiently understood. This study reports one year of soil monitoring following the de-sealing of a brownfield site in Milan (Italy). It [...] Read more.

De-sealing, or depaving, is increasingly adopted to restore soil permeability and support green infrastructure, yet its potential to recover soil functions remains insufficiently understood. This study reports one year of soil monitoring following the de-sealing of a brownfield site in Milan (Italy). It compares the evolution of pedoclimatic parameters in sealed and de-sealed soils and assesses the suitability of recycled aggregates (RAs) from demolition waste as a soil-forming material. Buried sensors continuously recorded pedoclimatic parameters, temperature, water content, and oxygen concentration, while periodic sampling was carried out to analyse soil chemical properties, bacterial community composition, and the quality of percolation water (heavy metal content). De-sealing immediately improved pedoclimatic conditions, enhancing soil aeration, water regulation, and heat exchange capacity. No significant variation was detected in soil chemical properties, apart from pH fluctuations linked to the leaching of alkaline ions from concrete-based RAs. The presence of RAs caused no adverse effects on either soil or percolation water. Bacterial community composition was strongly associated with soil organic carbon, C:N ratio, and soil water content, without showing clear temporal trends. Overall, the study demonstrates that de-sealing rapidly triggers soil functional recovery and that, when properly characterised for composition and contamination risk, RAs pose no evident threat to the surrounding environment. Full article

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17 pages, 1034 KB

Open AccessFeature PaperArticle

Development of Immunoenzyme Assay of Herbicide Acetochlor and Its Application to Soil Testing with Comparison of Sample Preparation Techniques

by Anna N. Berlina, Anatoly V. Zherdev and Boris B. Dzantiev

Soil Syst. 2025, 9(4), 127; https://doi.org/10.3390/soilsystems9040127 - 13 Nov 2025

Viewed by 1296

Abstract

Acetochlor is a selective herbicide affecting weeds of cereal plants. Its analysis in soils allows accessing their suitability for crops and risks of contamination of agricultural products. The aim of this study was to develop a microplate enzyme immunoassay for the determination of [...] Read more.

Acetochlor is a selective herbicide affecting weeds of cereal plants. Its analysis in soils allows accessing their suitability for crops and risks of contamination of agricultural products. The aim of this study was to develop a microplate enzyme immunoassay for the determination of acetochlor in soil extracts. For the development, rabbit antibodies specific to acetochlor were obtained by immunization with a conjugate of carrier protein with a derivative of acetochlor with mercaptopropionic acid. Another derivative with mercaptosuccinic acid was applied for immobilization on the solid phase. In the study, organic extracts have been obtained from soil varying solvents and their ratios, and using QuEChERS protocol. The extracts have been tested to estimate residual influences of the sample matrix. Optimal conditions for the immunoassay were selected, appropriate sample preparation techniques, and the composition of the medium for competitive immune interaction. The most effective approach involved dichloromethane extraction, followed by careful evaporation and subsequent reconstitution of the dry residue in a 10 mM phosphate-buffer solution supplemented with 0.1% gelatin. The resulting analytical system exhibited a detection limit of 59.4 ng/mL for acetochlor, with a working range spanning from 112 to 965 ng/mL. Taking into account the soil sample preparation, the LOD was estimated as 0.3 µg/g with the working range from 0.66 to 5.7 µg/g of soil. Analysis of prepared extracts from gray forest soil demonstrated a revealing of acetochlor between 74% and 124%. Full article

(This article belongs to the Special Issue Research on Trace and Hazardous Elements and Emerging Pollutants in Soils and Sediments)

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18 pages, 8991 KB

Open AccessArticle

Characterizing the Effects of Compaction on Agricultural Tilled Soil Macropore Characteristics Using X-Ray Computed Tomography

by Zhuohuai Guan, Tao Jiang, Haitong Li, Min Zhang, Mei Jin and Dong Jiang

Soil Syst. 2025, 9(4), 126; https://doi.org/10.3390/soilsystems9040126 - 12 Nov 2025

Viewed by 1530

Abstract

The risk of soil compaction by agricultural machinery threatens the structure and productivity of tilled soils. However, a quantitative understanding of how specific compaction loads alter the three-dimensional (3D) macropore architecture of tilled soil is still limited. This study employed X-ray computed tomography [...] Read more.

The risk of soil compaction by agricultural machinery threatens the structure and productivity of tilled soils. However, a quantitative understanding of how specific compaction loads alter the three-dimensional (3D) macropore architecture of tilled soil is still limited. This study employed X-ray computed tomography (CT) to quantitatively characterize the evolution of the 3D macropore network in clay soil under a series of controlled compaction pressures (0, 30, 60, 90, and 120 kPa). Our results revealed a non-monotonic response of macropore number to compaction, which initially increased due to the fragmentation of large pores before declining, peaking at 90 kPa. Most critically, we identified 90 kPa as a critical threshold, beyond which macroporosity and the volume of elongated beneficial pores underwent drastic reductions of 64.8% and 46.6%, respectively. Compaction significantly reduced pore connectivity and surface area, with larger macropores (>1000 μm) proving most vulnerable. The study establishes a quantitative link between applied pressure and specific pore-scale damage, providing a scientific basis for designing agricultural machinery with ground pressures below this critical threshold to preserve soil structure and function after tillage. Full article

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21 pages, 772 KB

Open AccessArticle

Effects of Different Tillage Systems on Soil Properties and Crop Yield in a Mollisol After 9, 22, and 25 Years of Implementation in Chapingo, Mexico

by Francisco González-Breijo, Antonio Fidel Santos-Hernández, Alejandra Sahagún-García, Luis Antonio Hernández-Pedraza, Juan Fernando Gallardo-Lancho and Joel Pérez-Nieto

Soil Syst. 2025, 9(4), 125; https://doi.org/10.3390/soilsystems9040125 - 12 Nov 2025

Viewed by 1941

Abstract

Sustainable soil management is crucial for balancing agricultural productivity and soil health in Mollisols under long-term tillage systems. This study evaluated the effects of no-tillage (NT), minimum conservation tillage (MCT), and conventional tillage (CT) on soil properties and maize yield in an irrigated [...] Read more.

Sustainable soil management is crucial for balancing agricultural productivity and soil health in Mollisols under long-term tillage systems. This study evaluated the effects of no-tillage (NT), minimum conservation tillage (MCT), and conventional tillage (CT) on soil properties and maize yield in an irrigated Mollisol in Chapingo, Mexico, over 9, 22, and 25 yr, using a Latin square design with three replications. MCT significantly enhanced soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP), and exchangeable potassium (EK) compared to NT and CT, achieving the highest maize grain yield (7.21 t ha⁻¹). NT exhibited the greatest SOC and EK in the surface layer. Physical properties, such as bulk density and porosity, remained stable across systems, reflecting Mollisol resilience. Although MCT optimized fertility and productivity, nutrient declines from 2021 to 2024 highlight the need for adaptive management strategies to sustain long-term productivity, supporting global soil conservation and sustainable agriculture goals. Full article

(This article belongs to the Special Issue Research on Soil Management and Conservation: 2nd Edition)

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24 pages, 3279 KB

Open AccessArticle

A Framework Based on Isoparameters for Clustering and Mapping Geophysical Data in Pedogeomorphological Studies

by Gustavo Vieira Veloso, Danilo César de Mello, Heitor Paiva Palma, Murilo Ferre Mello, Lucas Vieira Silva, Elpídio Inácio Fernandes-Filho, Márcio Rocha Francelino, Tiago Osório Ferreira, José Cola Zanuncio, Davi Feital Gjorup, Roney Berti de Oliveira, Marcos Rafael Nanni, Renan Falcioni and José A. M. Demattê

Soil Syst. 2025, 9(4), 124; https://doi.org/10.3390/soilsystems9040124 - 8 Nov 2025

Viewed by 1344

Abstract

Understanding soil variability supports improved land use and soil security. This study aimed to generate uniform geophysical classes by integrating data from three proximal geophysical sensors with synthetic soil and satellite images using machine learning, proposing a soil survey protocol. Geophysical data—natural gamma-ray [...] Read more.

Understanding soil variability supports improved land use and soil security. This study aimed to generate uniform geophysical classes by integrating data from three proximal geophysical sensors with synthetic soil and satellite images using machine learning, proposing a soil survey protocol. Geophysical data—natural gamma-ray emissions (eU, eTh, K⁴⁰), magnetic susceptibility (κ), and apparent electrical conductivity (ECa)—were collected in Piracicaba, Brazil, and clustered into homogeneous geophysical-isoparameter classes. These classes were modeled alongside Synthetic Soil Images (SYSIs), Sentinel-2 (0.45–2.29 μm), Landsat (0.43–12.51 μm) imagery, and morphometric variables. Empirical validation compared the resulting geophysical-isoparameter map with conventional pedological and lithological maps. The Support Vector Machine (SVM) algorithm exhibited the best classification performance. Results demonstrated that geophysical sensors quantitatively and qualitatively capture soil attributes linked to formation processes and types. The geophysical-isoparameter map correlated well with pedological and lithological patterns. The proposed protocol offers soil scientists a practical tool to delineate soil and lithological units using combined sensor data. Promoting collaboration among pedologists, pedometric mappers, and remote sensing experts, this approach presents a novel framework to enhance soil survey accuracy and efficiency. Full article

(This article belongs to the Special Issue Use of Modern Statistical Methods in Soil Science)

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13 pages, 5002 KB

Open AccessArticle

Abiotic Nitrogen Mineralization of Peptone by γ-MnO₂: Effects of Dissolved Oxygen and pH

by Jun Hong, Hang Zhang, Manli Xiao, Xiaoli Duan, Minmin Zhang, Li Yang, Hao Fan and Bo Liu

Soil Syst. 2025, 9(4), 123; https://doi.org/10.3390/soilsystems9040123 - 7 Nov 2025

Viewed by 1227

Abstract

Current research predominantly focuses on the microbial-driven processes of soil organic nitrogen mineralization, often overlooking the significant contributions of abiotic pathways mediated by reactive minerals. While manganese oxides are known to promote the abiotic mineralization of organic nitrogen, the influence of key environmental [...] Read more.

Current research predominantly focuses on the microbial-driven processes of soil organic nitrogen mineralization, often overlooking the significant contributions of abiotic pathways mediated by reactive minerals. While manganese oxides are known to promote the abiotic mineralization of organic nitrogen, the influence of key environmental factors on this process remains poorly understood. This study established a simulated system to investigate the effects of dissolved oxygen and pH on the γ-MnO₂-mediated abiotic nitrogen mineralization of peptone. The results showed that under an air atmosphere at pH 5.0–8.0, the rate of nitrogen mineralization from peptone catalyzed by γ-MnO₂ initially increased and then subsequently decreased. Dissolved oxygen was identified as a major electron acceptor in the peptone nitrogen mineralization process, playing a critical role in its rate and extent. Direct oxidation by Mn (IV) and Mn (III) within γ-MnO₂ accounted for 72.5% of the peptone nitrogen mineralization, and reactive oxygen species generated on the mineral surface accounted for 27.5% through a catalytic oxidation mechanism. This study provides a preliminary analysis of how key environmental factors influence the abiotic mineralization of protein-derived organic nitrogen, which is expected to deepen the understanding of soil organic nitrogen mineralization mechanisms, enrich the knowledge of nitrogen cycling in agricultural ecosystems, and provide a theoretical basis for efficient nitrogen management in farmland. Full article

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11 pages, 1167 KB

Open AccessArticle

Towards the Application of Complex-Valued Variograms in Soil Research

by Jarosław Zawadzki

Soil Syst. 2025, 9(4), 122; https://doi.org/10.3390/soilsystems9040122 - 7 Nov 2025

Viewed by 1007

Abstract

Variograms are a cornerstone of spatial analysis in geostatistics, traditionally applied to real-valued variables under the intrinsic hypothesis. Many soil properties, particularly when integrating magnetic and geochemical measurements, can be expressed as complex-valued variables that capture both magnitude and phase information. In the [...] Read more.

Variograms are a cornerstone of spatial analysis in geostatistics, traditionally applied to real-valued variables under the intrinsic hypothesis. Many soil properties, particularly when integrating magnetic and geochemical measurements, can be expressed as complex-valued variables that capture both magnitude and phase information. In the case of magnetic susceptibility, the imaginary component reflects energy losses associated with viscous magnetization, which in soils can indicate the presence of pedogenic ferrimagnetic minerals, while its relative increase may also reveal anthropogenic magnetite contamination. This study examines the formulation and application of variograms for such complex-valued variables in the context of soil research. Two complementary definitions are considered: an intrinsic-based approach, which directly estimates the variogram from increments and is applicable under the intrinsic hypothesis, and a covariance-based approach, which requires stronger second-order stationarity. Simulated complex-valued soil property data with controlled spatial structures were used to compare the behaviour of these formulations with their real-valued counterparts. The findings indicate that complex-valued variograms preserve additional spatial information, particularly related to local phase shifts, while maintaining compatibility with conventional variographic modelling. Full article

(This article belongs to the Special Issue Use of Modern Statistical Methods in Soil Science)

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18 pages, 2690 KB

Open AccessArticle

Precision Fertilization Strategies Modulate Growth, Physiological Performance, and Soil–Plant Nutrient Dynamics in Sabal palmetto

by Amir Ali Khoddamzadeh, Bárbara Nogueira Souza Costa and Milagros Ninoska Munoz-Salas

Soil Syst. 2025, 9(4), 121; https://doi.org/10.3390/soilsystems9040121 - 6 Nov 2025

Cited by 4 | Viewed by 2231

Abstract

Optimizing fertilizer management is essential for reducing salinity-related risks and improving nutrient efficiency in ornamental plant production. Fertilization enhances plant performance; however, excessive nutrient inputs can disrupt substrate chemistry, elevate salinity, and promote nitrogen leaching—particularly in containerized systems with limited rooting volume. This [...] Read more.

Optimizing fertilizer management is essential for reducing salinity-related risks and improving nutrient efficiency in ornamental plant production. Fertilization enhances plant performance; however, excessive nutrient inputs can disrupt substrate chemistry, elevate salinity, and promote nitrogen leaching—particularly in containerized systems with limited rooting volume. This study evaluated the growth, physiological performance, and soil–plant nutrient dynamics of Sabal palmetto (cabbage palm) cultivated under six fertilization regimes over 180 days in a subtropical shade-house environment. Treatments ranged from a single baseline application of 15 g per plant (T0) to a cumulative 75 g (T5) using granular slow-release fertilizer. Morphological traits (plant height: 26–70 cm; leaf number: 4–18) and physiological indices (atLEAF⁺: 34.3–66.4; NDVI: 0.26–0.77) were monitored every 30 days. Substrate nitrogen and carbon concentrations increased from 0.57% and 41.78% at baseline to 1.24% and 42.94% at 180 days, while foliar nitrogen ranged from 1.46% to 2.57%. Fertilization significantly influenced all parameters (p < 0.05). Higher fertilization levels elevated electrical conductivity, salinity, and nitrogen leaching, with principal component analysis revealing strong positive associations among total nitrogen, electrical conductivity, and salinity. Moderate fertilization (T2 = 45 g) maintained favorable substrate chemistry, high foliar nitrogen, and balanced canopy growth with minimal nutrient losses. Sensor-based chlorophyll indices (atLEAF⁺ and NDVI) correlated strongly (r = 0.71, p < 0.001), confirming their reliability as non-destructive diagnostics for nitrogen management. These findings demonstrate that integrating optical monitoring with adaptive fertilization mitigates substrate salinization, sustains ornamental quality, and promotes the sustainable cultivation of Sabal palmetto in urban horticultural systems. Full article

(This article belongs to the Special Issue Advances in the Prediction and Remediation of Soil Salinization: 2nd Edition)

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20 pages, 6954 KB

Open AccessArticle

Early Peat Diagenesis Controls on Bromine Accumulation

by Antonio Martínez Cortizas, Mohamed Traoré, Olalla López-Costas, Géraldine Sarret and Stéphane Guédron

Soil Syst. 2025, 9(4), 120; https://doi.org/10.3390/soilsystems9040120 - 5 Nov 2025

Cited by 2 | Viewed by 925

Abstract

Peatlands are natural reservoirs of organobromine compounds. Important advances have been made in unraveling the mechanisms involved in bromine (Br) retention in the peat but, to our knowledge, the temporal and spatial variation of the peat organic matter (OM) bromination has not been [...] Read more.

Peatlands are natural reservoirs of organobromine compounds. Important advances have been made in unraveling the mechanisms involved in bromine (Br) retention in the peat but, to our knowledge, the temporal and spatial variation of the peat organic matter (OM) bromination has not been fully researched. Here, we present the study of 12 short cores (c. 30 cm, c. 150–200 years of peat accumulation) sampled from a small (c. 1 ha) area of an oceanic blanket peatland from northwestern Spain. We combine Br concentrations, spectroscopic analysis (FTIR–ATR), and structural equation statistical modelling (SEM). Our results show that Br is significantly correlated to proxies of peat aerobic decomposition, with concentrations increasing with depth in all cores (×2–10 times). Strong spatial heterogeneity was observed, with some cores showing much higher Br maximum concentrations and larger increases with depth. SEM modelling indicated that various OM functionalities contribute to Br accumulation and that their effects change with depth/age, with aromatics becoming dominant after 20–90 years. Thus, changes in organic matter molecular composition, linked to early peat diagenesis, and the geochemical conditions governing it exerted a strong control on Br accumulation in the studied peatland. Bromine wet deposition was not found to be a limiting factor. Full article

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19 pages, 13114 KB

Open AccessArticle

Transient Effects of Biochar and Drainage Systems on Soil Granulometry, Bulk Density, and Porosity in Clay Loam Anthrosols Under Monsoon Climate

by Anastasia Brikmans, Olga Nesterova, Andrei Egorin, Mariia Bovsun, Viktoriia Semal and Nikolay Sakara

Soil Syst. 2025, 9(4), 119; https://doi.org/10.3390/soilsystems9040119 - 5 Nov 2025

Viewed by 1210

Abstract

Heavy-textured soils in monsoon-affected regions face challenges related to waterlogging and structural degradation, yet the long-term efficacy of biochar as a physical soil amendment under such conditions remains inadequately understood. This two-year field study (2018–2019) therefore evaluated the transient impacts of birch-derived biochar [...] Read more.

Heavy-textured soils in monsoon-affected regions face challenges related to waterlogging and structural degradation, yet the long-term efficacy of biochar as a physical soil amendment under such conditions remains inadequately understood. This two-year field study (2018–2019) therefore evaluated the transient impacts of birch-derived biochar (360–380 °C pyrolysis; 0, 1, 3 kg/m²), subsurface drainage systems, and fertilizer regimes on key physical properties of Endoargic Anthrosols (clay loam) in coastal Primorsky Krai, Russia. Granulometric composition remained stable (silt loam: sand 42–48%, silt 38–44%, clay 12–16%), though drainage significantly increased the silt fraction by >7.5% (p < 0.05). Biochar induced short-term reductions in bulk density (ρ_b; max −12% at 3 kg/m², 2018) and aggregate density (ρ_a; max −9.3%, 2018), but these effects dissipated by 2019 due to tillage redistribution and monsoonal fragmentation, as verified by SEM. Total porosity fluctuated seasonally (0.50–0.65 cm³/cm³), peaking post-tillage but declining under monsoon saturation, with no significant sustained biochar contribution. Crucially, intra-aggregate pore architecture (2–50 nm) resisted amendment-induced changes; N₂ adsorption showed treatment-invariant mesopore dominance (65–75% volume; mean pore diameter 17–21 nm), attributable to biochar’s physical exclusion (>1 µm particles from sub-0.5 µm pores) and inert fragmentation. Drainage dominated structural dynamics, modulating pore volume seasonally (−15% in 2018; +18% in 2019), while organic fertilizer enhanced porosity through polysaccharide-stabilized microaggregation (+22%, 2019). We conclude that biochar’s physical benefits in clay loams under monsoon climates are transient and dose-dependent, operating primarily through inter-aggregate macroporosity rather than intra-aggregate modification, necessitating reapplication for sustained improvements. Full article

(This article belongs to the Special Issue Research on Soil Management and Conservation: 2nd Edition)

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18 pages, 2682 KB

Open AccessArticle

Soil Management and Machine Learning Abandonment Detection in Mediterranean Olive Groves Under Drought: A Case Study from Central Spain

by Giovanni Marchese, Juan E. Herranz-Luque, Sohail Anwar, Valentina Vaglia, Chiara Toffanin, Ana Moreno-Delafuente, Blanca Sastre and María José Marqués Pérez

Soil Syst. 2025, 9(4), 118; https://doi.org/10.3390/soilsystems9040118 - 31 Oct 2025

Viewed by 1709

Abstract

In Mediterranean semi-arid regions, rainfed olive groves are increasingly being abandoned due to drought, low profitability, and rural depopulation. The long-term impact of abandonment on soil conditions is debated, as it may promote vegetation recovery or lead to degradation. In contrast, some farmers [...] Read more.

In Mediterranean semi-arid regions, rainfed olive groves are increasingly being abandoned due to drought, low profitability, and rural depopulation. The long-term impact of abandonment on soil conditions is debated, as it may promote vegetation recovery or lead to degradation. In contrast, some farmers are adopting low-disturbance management practices that allow spontaneous vegetation to establish. These contrasting scenarios offer valuable opportunities for comparison. This study aims to develop a framework to assess the impact of different management regimes on soil health and to investigate (1) the impact of spontaneous vegetation cover (SVC) and tillage regimes on soil organic carbon (SOC), and (2) the long-term ecological dynamics of abandoned groves, through a combination of field surveys, remote sensing, and object detection. SOC was assessed using both ground-based and remote sensing-derived indicators. Vegetation cover was quantified via a grid point intercept method. Field data were integrated with a land-use monitoring framework that includes abandonment assessment through historical orthophotos and a deep learning model (YOLOv12) to detect active and abandoned olive groves. Results show that abandoned zones are richer in SOC than active ones. In particular, the active groves with SVC exhibit a mean SOC of 1%, which is higher than that of tilled groves, where SOC is 0.45%, with no apparent moisture loss. Abandoned groves can be reliably identified from aerial imagery, achieving a recall of 0.833 for abandoned patches. Our results demonstrate the potential of YOLOv12 as an innovative and accessible tool for detecting zones undergoing ecological regeneration or degradation. The study underscores the ecological and agronomic potential of spontaneous vegetation in olive agroecosystems. Full article

(This article belongs to the Special Issue Research on Soil Management and Conservation: 2nd Edition)

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2 pages, 139 KB

Open AccessCorrection

Correction: Hazratqulov et al. Processing Municipal Waste for Phytostabilization of Heavy Metal Contaminated Soils. Soil Syst. 2024, 8, 109

by Shohnazar Hazratqulov, Georgina von Ahlefeldt, Rui Liu, Holger Bessler, Hernán Almuina-Villar, Alba Dieguez-Alonso and Christof Engels

Soil Syst. 2025, 9(4), 117; https://doi.org/10.3390/soilsystems9040117 - 28 Oct 2025

Viewed by 588

Abstract

In the original article [...] Full article

32 pages, 7132 KB

Open AccessArticle

Synthetic Bacterial Consortium Induces Dynamic Shifts in Fungal Community and Alters Microbial Network Topology in Barley Soil Under Field Conditions

by Roderic Gilles Claret Diabankana, Ernest Nailevich Komissarov, Daniel Mawuena Afordoanyi, Bakhtiyar Islamov, Artemiy Yurievich Sukhanov, Elena Shulga, Maria Nikolaevna Filimonova, Keremli Saparmyradov, Natalia V. Trachtmann and Shamil Z. Validov

Soil Syst. 2025, 9(4), 116; https://doi.org/10.3390/soilsystems9040116 - 19 Oct 2025

Cited by 1 | Viewed by 2410

Abstract

Microorganisms are fundamental drivers of soil productivity, mediating nutrient cycling and pathogen suppression. In this study, we evaluated changes in the fungal community in the soil of barley (Hordeum vulgare L.) in a field experiment involving the application of a consortium of [...] Read more.

Microorganisms are fundamental drivers of soil productivity, mediating nutrient cycling and pathogen suppression. In this study, we evaluated changes in the fungal community in the soil of barley (Hordeum vulgare L.) in a field experiment involving the application of a consortium of Paenibacillus pabuli, Priestia megaterium, Pseudomonas koreensis, and Pseudomonas orientalis. Seed pretreatment and seed pretreatment followed by rhizosphere drenching at different growth stages were implemented. Regarding fungal communities in bulk soil, the rhizospheres of untreated and treated plants were characterized based on full-length ribosomal RNA gene (18S-5.8S-28S) metabarcoding sequencing. Despite the compositional shifts, no statistical differences were observed among the alpha diversity metrics. Seed treatment resulted in long-term, targeted suppression of Fusarium graminearum, Fusarium fujikuroi, Fusarium musae, and Fusarium verticillioides from the booting through flowering and dough development stages, outperforming seed pretreatment followed by rhizosphere drenching. A low-modularity network was observed in the rhizosphere of untreated plants. Seed treatment fostered a highly interconnected and uniform network with low hub-betweenness scores. Rhizosphere drenching of pretreated seeds shifted the network topology toward higher hub-betweenness scores, reducing their connectivity by up to 10% in the rhizosphere and bulk soil. These findings provide a framework for optimizing the soil ecosystem for sustainable agriculture. Full article

(This article belongs to the Topic Interactions between Plants and Soil Microbes in Natural Ecosystem)

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19 pages, 1334 KB

Open AccessArticle

Spatial Decoupling of Biological and Geochemical Phosphorus Cycling in Podzolized Soils

by Daniel F. Petticord, Benjamin T. Uveges, Elizabeth H. Boughton, Brian D. Strahm and Jed P. Sparks

Soil Syst. 2025, 9(4), 115; https://doi.org/10.3390/soilsystems9040115 - 16 Oct 2025

Cited by 2 | Viewed by 1659

Abstract

Phosphorus (P) is essential to life yet constrained by finite reserves, heterogeneous distribution, and strong chemical binding to soil minerals. Pedogenesis progressively alters the availability of P: in ‘young’ soils, P associated with Ca and Mg is relatively labile, while in ‘old’ soils, [...] Read more.

Phosphorus (P) is essential to life yet constrained by finite reserves, heterogeneous distribution, and strong chemical binding to soil minerals. Pedogenesis progressively alters the availability of P: in ‘young’ soils, P associated with Ca and Mg is relatively labile, while in ‘old’ soils, acidification and leaching deplete base cations, shifting P into organic matter and recalcitrant Al- and Fe-bound pools. Podzolized soils (Spodosols) provide a unique lens for studying this transition because podzolization vertically segregates these dynamics into distinct horizons. Organic cycling dominates the surface horizon, while downward translocation of Al, Fe, and humus creates a spodic horizon that immobilizes P through sorption and co-precipitation in amorphous organometal complexes. This spatial separation establishes two contrasting P pools—biologically dynamic surface P and mineral-stabilized deep P—that may be variably accessible to plants and microbes depending on depth, chemistry, and hydrology. We synthesize mechanisms of spodic P retention and liberation, including redox oscillations, ligand exchange, root exudation, and physical disturbance, and contrast these with strictly mineral-driven or biologically dominated systems. We further propose that podzols serve as natural experimental models for ecosystem aging, allowing researchers to explore how P cycling reorganizes as soils develop, how vertical stratification structures biotic strategies for nutrient acquisition, and how deep legacy P pools may be remobilized under environmental change. By framing podzols as a spatial analogue of long-term weathering, this paper identifies them as critical systems for advancing our understanding of nutrient limitation, biogeochemical cycling, and sustainable management of P in diverse ecosystems. Full article

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14 pages, 917 KB

Open AccessArticle

Improving Chernozem Fertility and Barley Yield Through Combined Application of Phosphorus Fertilizer and Ash–Carbon Amendment

by Abilzhan Khussainov, Anara Sarsenova, Anar Ayapbergenova, Gulmira Kyzdarbekova and Ekaterina Bazilevskaya

Soil Syst. 2025, 9(4), 114; https://doi.org/10.3390/soilsystems9040114 - 16 Oct 2025

Viewed by 1370

Abstract

Phosphorus deficiency and declining organic matter limit crop productivity in Northern Kazakhstan’s chernozem soils. This study evaluates whether the combined application of phosphorus fertilizer and an ash-carbon amendment from industrial by-products can improve soil fertility and barley yield. In a three-year field experiment [...] Read more.

Phosphorus deficiency and declining organic matter limit crop productivity in Northern Kazakhstan’s chernozem soils. This study evaluates whether the combined application of phosphorus fertilizer and an ash-carbon amendment from industrial by-products can improve soil fertility and barley yield. In a three-year field experiment (2018–2020), four P rates (1/10, 1/5, 1/2, and the full recommended dose, Prec) were tested with 100 kg ha⁻¹ of ash–carbon product (“Agrobionov”). Across growth stages, we measured cellulolytic microbial activity, water-stable soil aggregates (%WSA), and grain yield. Relative to the control, P + ash–carbon increased microbial activity by up to 57.6% and %WSA by up to 76%. The highest yield (1.32 t ha⁻¹) occurred with Agrobionov + ½ Prec, a 51.7% increase over the control. These results indicate that pairing moderate P rates with an ash–carbon amendment enhances soil biological and physical properties and improves yield in P-deficient chernozems, supporting the sustainable use of industrial by-products as cost-effective soil amendments. Future work should assess long-term effects on C sequestration, nutrient cycling, and economic feasibility. Full article

(This article belongs to the Special Issue Integrated Soil Management: Food Supply, Environmental Impacts, and Socioeconomic Functions: 2nd Edition)

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15 pages, 1480 KB

Open AccessArticle

Turning Waste into Fertilizer: Aloe vera Leaf Shavings Improve Plant Growth and Support Soil Fertility in Organic Systems

by Isaiah E. Jaramillo, Carine Cocco, James Jihoon Kang, Chu-Lin Cheng and Engil Pereira

Soil Syst. 2025, 9(4), 113; https://doi.org/10.3390/soilsystems9040113 - 15 Oct 2025

Cited by 2 | Viewed by 5291

Abstract

The Aloe vera industry discards large amounts of outer leaf tissue (“shavings”), creating an opportunity to repurpose this byproduct as a sustainable fertilizer. This study evaluated whether aloe shavings can serve as a plant-based alternative to compost in organic Aloe vera production. A [...] Read more.

The Aloe vera industry discards large amounts of outer leaf tissue (“shavings”), creating an opportunity to repurpose this byproduct as a sustainable fertilizer. This study evaluated whether aloe shavings can serve as a plant-based alternative to compost in organic Aloe vera production. A field trial in the Lower Rio Grande Valley of Texas tested three treatments: aloe shavings (applied to supply 39 kg N ha⁻¹), organic compost (39 kg N ha⁻¹), and a non-fertilized control. Laboratory incubations further assessed nitrogen mineralization and microbial respiration. Aloe shavings significantly enhanced vegetative growth: leaf number increased from 5.7 to 12.3 leaves per plant (+115% over the season), and leaf length rose from 20 to 32 cm, with the greatest gains in September and March (p < 0.05). At harvest, plants receiving aloe shavings produced 456 g total leaf weight and 151 g gel weight per plant, compared to 375 g and 108 g in the control. Incubations showed initial nitrogen immobilization (negative mineralization) but subsequent slow release, while microbial respiration was higher in compost (2.3 mg CO₂-C kg⁻¹ day⁻¹) than aloe shavings (1.4 mg CO₂-C kg⁻¹ day⁻¹). These results highlight aloe shavings as a low-cost, slow-release organic amendment that reduces waste, supports circular economy practices, and enhances Aloe vera growth without mineral nitrogen addition. Full article

(This article belongs to the Special Issue Soil Fertility Management, Mitigating GHG Emissions and Sustainable Agriculture: 2nd Edition)

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27 pages, 3476 KB

Open AccessArticle

Land Use Modifies the Inherent Effect of Soil Properties on Soil Bacterial Communities in Humid Tropical Watersheds

by Sunshine A. De Caires, Sabine Reinsch, Duraisamy Saravanakumar, Chaney St. Martin, Mark N. Wuddivira, Bernie J. Zebarth, Fuat Kaya, Mengying Liu, Durga P. M. Chinthalapudi, Shankar Ganapathi Shanmugam and Bobbi Helgason

Soil Syst. 2025, 9(4), 112; https://doi.org/10.3390/soilsystems9040112 - 15 Oct 2025

Viewed by 2241

Abstract

Soil bacterial communities are vital for ecosystem functioning in the humid tropics, yet their response to land-use change remains poorly understood. This knowledge gap is exacerbated by the lack of long-term studies. We employed a space-for-time substitution approach to assess the effects of [...] Read more.

Soil bacterial communities are vital for ecosystem functioning in the humid tropics, yet their response to land-use change remains poorly understood. This knowledge gap is exacerbated by the lack of long-term studies. We employed a space-for-time substitution approach to assess the effects of land-use intensification on soil bacterial communities across a gradient of anthropogenic disturbance in Trinidad. Three sub-watersheds (Arouca = pristine, Maracas = intermediate, Tacarigua = intensive) were selected, each containing adjacent forest, grassland, and agricultural land uses. We combined geophysical soil apparent electrical conductivity (ECa-directed) sampling with 16S rDNA gene amplicon sequencing to characterize bacterial communities and their relationships with soil and landscape properties. Soil properties were the primary determinant of bacterial community structure, explaining 56% of the variation (p < 0.001), with pH, clay content, hygroscopic water, and nutrient availability as key drivers. Bacterial α-diversity differed significantly among sub-watersheds (p < 0.01), with Tacarigua exhibiting lower richness and diversity compared to Arouca and Maracas, but not across land uses. While a core microbiome of ten bacterial families was ubiquitous across land uses, indicating a stable foundational community, land-use intensification significantly altered β-diversity (p < 0.01 among sub-watersheds). Agricultural soils showed the greatest divergence from forest soils (p < 0.05), with a marked decline in key Proteobacterial families (e.g., Xanthomonadaceae, Pseudomonadaceae) involved in nutrient cycling and plant growth promotion. Although inherent soil properties shape the core microbiome, land-use intensification acts as a strong secondary filter, shifting soil bacterial communities toward more stress-resistant Firmicutes with potentially less diverse functions. Our findings demonstrate the utility of integrating space-for-time substitution with molecular profiling to predict long-term microbial responses to environmental change in vulnerable tropical ecosystems. Full article

(This article belongs to the Special Issue Land Use and Management on Soil Properties and Processes: 2nd Edition)

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32 pages, 5461 KB

Open AccessArticle

Physical and Chemical Properties of Fire-Affected Soils from the Sagebrush Ecosystem of the Western US: A Laboratory Study

by Yasaman Raeofy, Vera Samburova, Markus Berli, Eden Furtak-Cole, Brad Sion, Sally Houseman, Kristine Lu, William Curtiss, Andrew J. Andrade, Bianca Martinez, Andrey Y. Khlystov and Hans Moosmüller

Soil Syst. 2025, 9(4), 111; https://doi.org/10.3390/soilsystems9040111 - 13 Oct 2025

Viewed by 2142

Abstract

This study aims to understand the effects of wildfires in sagebrush ecosystem on soil properties by examining connections between Soil Water Repellency (SWR), reflectance, and chemistry. Ash and burned soil samples were collected after performing laboratory burns of three common sagebrush plants: sagebrush, [...] Read more.

This study aims to understand the effects of wildfires in sagebrush ecosystem on soil properties by examining connections between Soil Water Repellency (SWR), reflectance, and chemistry. Ash and burned soil samples were collected after performing laboratory burns of three common sagebrush plants: sagebrush, rabbitbrush, and bitterbrush. The collected samples were analyzed for their physical properties, including SWR measured by Water Drop Penetration Time (WDPT) and Apparent Contact Angle (ACA), and solar spectral reflectance in the wavelength range of 350 to 2500 nm. Chemical functional groups of the samples were analyzed using Fourier-Transform Infrared (FTIR) spectroscopy. WDPT and ACA values were in the range of 1 to 600 s and ~10° to 88°, respectively, for all three tested fuels. The FTIR analysis showed a decrease (~2 to 4 times) in the ratio of COO⁻/C=C signals for the burned soil samples compared to the unburned soil samples. Overall, increase in temperature and ACA levels for the samples of burned and burned soil from a 2 cm depth led to increased formation of non-polar compounds with C=C functional groups, and decarboxylation. Full article

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20 pages, 1116 KB

Open AccessArticle

Investigating the Effects of Soil Type and Potassium Fertiliser Timing on Potassium Leaching: A Five-Soil Lysimeter Study

by Thomas P. McCarthy, John B. Murphy and Patrick J. Forrestal

Soil Syst. 2025, 9(4), 110; https://doi.org/10.3390/soilsystems9040110 - 13 Oct 2025

Cited by 1 | Viewed by 2691

Abstract

Potassium (K) is essential for grassland productivity, but soil K leaching can reduce fertiliser use efficiency, increasing environmental losses. International evidence suggests soil type and K fertiliser timing influence K leaching, yet limited data exist for Ireland’s diverse soil types. This study investigated [...] Read more.

Potassium (K) is essential for grassland productivity, but soil K leaching can reduce fertiliser use efficiency, increasing environmental losses. International evidence suggests soil type and K fertiliser timing influence K leaching, yet limited data exist for Ireland’s diverse soil types. This study investigated the effects of K fertiliser timing (autumn, winter, and spring) and soil type on K leaching using a controlled lysimeter facility with five representative Irish soils sown with perennial ryegrass. Potassium fertiliser (125 kg K ha⁻¹) was applied in October, December, or February, with leachate collected from October to April. Soil type affected cumulative K leaching (1.4–9.8 kg ha⁻¹; p ≤ 0.001), with the greatest losses observed in sandy soils. Potassium and nitrogen uptake in spring-harvested grass were also influenced by soil type (p ≤ 0.05), with strong positive correlation between the two nutrients (R² = 0.78; p ≤ 0.001). Temporally, significant interactions (p ≤ 0.05) between K application timing and sampling date were found for K leachate in three of the five soils tested. Autumn and winter applications tended to increase cumulative leaching risk, especially on coarser-textured soils such as the Oakpark soil (p ≤ 0.05). The study indicates that applying K in early spring will tend to reduce leaching K losses, particularly on sandy soils. Full article

(This article belongs to the Topic Soil Health and Nutrient Management for Crop Productivity)

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22 pages, 2913 KB

Open AccessArticle

Spatial Variability and Temporal Changes of Soil Properties Assessed by Machine Learning in Córdoba, Argentina

by Mariano A. Córdoba, Susana B. Hang, Catalina Bozzer, Carolina Alvarez, Lautaro Faule, Esteban Kowaljow, María V. Vaieretti, Marcos D. Bongiovanni and Mónica G. Balzarini

Soil Syst. 2025, 9(4), 109; https://doi.org/10.3390/soilsystems9040109 - 10 Oct 2025

Cited by 2 | Viewed by 2374

Abstract

Understanding the temporal dynamics and spatial distribution of key soil properties is essential for sustainable land management and informed decision-making. This study assessed the spatial variability and decadal changes (2013–2023) of topsoil properties in Córdoba, central Argentina, using digital soil mapping (DSM) and [...] Read more.

Understanding the temporal dynamics and spatial distribution of key soil properties is essential for sustainable land management and informed decision-making. This study assessed the spatial variability and decadal changes (2013–2023) of topsoil properties in Córdoba, central Argentina, using digital soil mapping (DSM) and machine learning (ML) algorithms. Three ML methods—Quantile Regression Forest (QRF), Cubist, and Support Vector Machine (SVM)—were compared to predict soil organic matter (SOM), extractable phosphorus (P), and pH at 0–20 cm depth, based on environmental covariates related to site climate, vegetation, and topography. QRF consistently outperformed the other models in prediction accuracy and uncertainty, confirming its suitability for DSM in heterogeneous landscapes. Prediction uncertainty was higher in marginal mountainous areas than in intensively managed plains. Over ten years, SOM, P, and pH exhibited changes across land-use classes (cropland, pasture, and forest). Extractable P declined by 15–35%, with the sharpest reduction in croplands (−35.4%). SOM decreased in croplands (−6.7%) and pastures (−3.1%) but remained stable in forests. pH trends varied, with slight decreases in croplands and forests and a small increase in pastures. By integrating high-resolution mapping and temporal assessment, this study advances DSM applications and supports regional soil monitoring and sustainable land-use planning. Full article

(This article belongs to the Special Issue Use of Modern Statistical Methods in Soil Science)

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Soil Syst., Volume 9, Issue 4 (December 2025) – 33 articles

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