Soil Systems

16 pages, 2366 KB

Open AccessArticle

Assessment of Arsenic and Lead in Urban Park Soils in Newark, New Jersey, USA

by Suah Yekeh and Ashaki A. Rouff

Soil Syst. 2026, 10(2), 34; https://doi.org/10.3390/soilsystems10020034 - 21 Feb 2026

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Soils in seven urban parks in Newark, New Jersey (NJ), United States, were evaluated for arsenic (As) and lead (Pb) by field and laboratory methods. Surface (S1, 0–3 cm) and near-surface (S2, 4–7 cm) soils in high-contact areas of the parks were analyzed [...] Read more.

Soils in seven urban parks in Newark, New Jersey (NJ), United States, were evaluated for arsenic (As) and lead (Pb) by field and laboratory methods. Surface (S1, 0–3 cm) and near-surface (S2, 4–7 cm) soils in high-contact areas of the parks were analyzed by portable X-ray fluorescence (XRF) spectroscopy. Median concentrations of As and Pb in S1 profiles were higher than median concentrations in NJ Urban soils. In S1 and S2 profiles, 39–50% of As and 56–58% of Pb concentrations exceeded the NJ Department of Environmental Protection limits for residential soils, with most hotspots located in two of the seven parks. The contamination factor (

{C F}_{A s}

= 1.5–4.3;

{C F}_{P b}

= 1.7–9.8), enrichment factor (

{E F}_{A s}

= 1.7–4.6;

{E F}_{P b}

= 2.0–10.4), and geoaccumulation index (

I_{g e o A s}

= −0.1–1.5;

I_{g e o P b}

= 0.1–2.7), calculated relative to NJ Rural soil concentrations, confirmed the contamination of park soils with As and Pb, with higher contamination and enrichment indices for Pb. Tessier sequential extraction indicated the metals were mostly in the reducible fraction, with median values of 80% As and 65% Pb bound to iron and manganese oxides. The fractionation suggests limited environmental mobility of the metals under current soil conditions. However, human exposure to As and Pb remains a concern as the soils are located in high-contact recreational areas. Full article

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21 pages, 3826 KB

Open AccessArticle

Drivers of Input and Stabilisation Control Subsoil Organic Carbon Content in Perennial Pasture Grazing Systems

by Evanna McGuinness, Abraham J. Gibson, Joanne Oakes, Mark Farrell and Naomi S. Wells

Soil Syst. 2026, 10(2), 33; https://doi.org/10.3390/soilsystems10020033 - 20 Feb 2026

Viewed by 1076

Abstract

Subsoil (30–100 cm) soil organic carbon (SOC) is a poorly constrained but potentially significant component of terrestrial carbon budgets. While controls on subsoil SOC are likely to differ from those affecting topsoil, few studies have quantified them. This study quantified subsoil (30–100 cm) [...] Read more.

Subsoil (30–100 cm) soil organic carbon (SOC) is a poorly constrained but potentially significant component of terrestrial carbon budgets. While controls on subsoil SOC are likely to differ from those affecting topsoil, few studies have quantified them. This study quantified subsoil (30–100 cm) SOC stocks and identified the controls on its spatial distribution across perennial grazing systems in northeast New South Wales, Australia. SOC was measured to 1 m depth across 54 long-term perennial pasture grazing paddocks on nine farms. A Random Forest regression model was then used to determine the relationship between subsoil SOC and drivers represented by the scorpan model of soil formation. Subsoil SOC contributed ~50% of total SOC stocks in the top metre of soil, with a median of 65.8 t ha⁻¹ stored in subsoil. Our study found that drivers of SOC input and turnover (subsoil total nitrogen, 10–30 cm SOC content, and climate), as well as pedogenic processes influencing SOC stabilisation (weathering index), were the most important factors in the determination of subsoil SOC content. This contrasts with previous findings where abiotic factors linked to parent material and soil properties were the major controls on subsoil SOC distribution and highlights links between both input and stabilisation in perennial grazing systems. Full article

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19 pages, 2542 KB

Open AccessArticle

Assessment of Soil Degradation by Erosion in a Small Catchment in the Black Soil Region of Northeast China

by Fujun Liu, Hangyu Zhang, Jianhui Zeng and Zhonglu Guo

Soil Syst. 2026, 10(2), 32; https://doi.org/10.3390/soilsystems10020032 - 19 Feb 2026

Cited by 2 | Viewed by 1180

Abstract

Soil erosion and deposition processes act as key drivers of soil resources distribution across landscapes, affecting soil quality and functionality. However, the impacts of long-term soil erosion on soil quality and degradation in the black soil region remain unclear. Here, we assessed soil [...] Read more.

Soil erosion and deposition processes act as key drivers of soil resources distribution across landscapes, affecting soil quality and functionality. However, the impacts of long-term soil erosion on soil quality and degradation in the black soil region remain unclear. Here, we assessed soil quality and degradation as a consequence of historical erosion and soil redistribution in an agricultural catchment in Northeast China. Soil quality indices (SQI) were calculated using both linear and non-linear scoring function methods, along with soil indicator selection approaches, including Total Data Set (TDS) and Minimum Data Set (MDS). Soil degradation indices (SDI), resistance indices (SRI), and the change of SQI (CSQI) were computed and compared. The mean SDI for bulk density (BD) and sand was greater than 0. When BD and sand were excluded, the mean SDI and SRI for the 0–10 cm and 10–20 cm soil layers were −29.8% and −21.9%, and 0.57 and 0.65, respectively. Surface soil (0–10 cm) organic matter (SOM), available potassium (AK), structure stability index (SSI), and total nitrogen (TN) in eroding sites, as well as AK, SSI, SOM, TN, and available phosphorus (AP) in depositional sites, are particularly sensitive to long-term erosion. Field capacity, sand, AK, and SSI were selected to develop the SQI, with the non-linear method utilizing MDS outperforming other SQIs. Most SQIs in eroding sites were lower than those in depositional sites and increased with higher soil redistribution rates. The assessment of soil degradation using SDI, SRI, and CSQI revealed that long-term erosion markedly diminished soil quality, although deposition somewhat alleviated this impact. The lower SQI in the 10–20 cm compared to the 0–10 cm soil layer was primarily attributed to decreased FC, while long-term erosion degraded soil quality by negatively affecting AK and sand content. These findings enhance our comprehension of soil degradation caused by erosion in the Mollisol region of Northeast China. Full article

(This article belongs to the Topic Soil Quality: Monitoring Attributes and Productivity)

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31 pages, 4557 KB

Open AccessArticle

FTIR–Fluorescence Two-Dimensional Correlation Spectroscopy of Soil Water-Extractable Particle Fractions by Sequential Membrane Filtration

by Dmitry S. Volkov, Olga B. Rogova, Svetlana T. Ovseyenko and Mikhail A. Proskurnin

Soil Syst. 2026, 10(2), 31; https://doi.org/10.3390/soilsystems10020031 - 13 Feb 2026

Cited by 1 | Viewed by 2165

Abstract

The distribution of water-soluble organic matter (or dissolved organic matter DOM) in narrow (nano-and micrometer) fractions of chernozem was studied by sequential filtration on track-etched membranes. Multimodal (IR and fluorescence) two-dimensional correlation (2D-COS) spectroscopy was used. Protocols for attenuated total reflectance (ATR) FTIR [...] Read more.

The distribution of water-soluble organic matter (or dissolved organic matter DOM) in narrow (nano-and micrometer) fractions of chernozem was studied by sequential filtration on track-etched membranes. Multimodal (IR and fluorescence) two-dimensional correlation (2D-COS) spectroscopy was used. Protocols for attenuated total reflectance (ATR) FTIR of DOM were proposed. ATR-FTIR 2D-COS provides a larger volume of information on characteristic bands compared to traditional FTIR, especially in C–H ranges (3000–2800 and 1450–1300 cm⁻¹). The fluorescence excitation–emission matrix 2D-COS showed that the indexes and ratios of humic- to protein-like compounds are reproducible, and exhibit significant variation among size fractions, with maximum amounts of saturated humic-like compounds in the largest (2–10 μm) and finest fractions (0.01–0.03 μm), while medium fractions (0.05–1 μm) are dominated by fulvic acids and fresh organic matter. Heterospectral fluorescence–IR 2D-COS enhanced the accuracy of identification and assessment of DOM group composition and showed that C–H IR band intensities correlate with tyrosine-like EEM bands and biogenic fluorescence indexes, while carboxylic components have humate-like bands and humification fluorescence indexes. Element profiles in DOM fractions correlate with fluorescence indexes; humification indexes with P, S, Cr, Mg, Ca, Cu, and Zn; biogenic with Mg, P, Cr, Cd, K, S, and Ca. Full article

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12 pages, 752 KB

Open AccessArticle

Optimal Timing of Lime Application for Reducing Cadmium Accumulation in Rice: A Growth-Stage-Dependent Study

by Hongbiao Cui, Zhanlong Liu, Binglu Bao, Lijun Zhou, Shiwen Zhang and Jun Zhou

Soil Syst. 2026, 10(2), 30; https://doi.org/10.3390/soilsystems10020030 - 12 Feb 2026

Cited by 1 | Viewed by 1108

Abstract

Soil cadmium (Cd) pollution poses a significant threat to rice production and food safety. Although lime amendment is known to reduce Cd bioavailability in soils, the optimal growth stage for its application remains unclear. This study employed pot experiments with the rice cultivar [...] Read more.

Soil cadmium (Cd) pollution poses a significant threat to rice production and food safety. Although lime amendment is known to reduce Cd bioavailability in soils, the optimal growth stage for its application remains unclear. This study employed pot experiments with the rice cultivar Wuyouhuazhan as the test material to investigate the effects of lime (Ca(OH)₂) application during four critical rice growth stages, namely seedling (LS), tillering (LT), booting (LB), and filling (LF), on Cd availability, soil properties, and Cd accumulation in rice. Results showed that lime application at all stages significantly reduced soil-available Cd by 53–63%, primarily by promoting the transformation of exchangeable Cd into more stable residual forms. Lime also increased biomass across rice tissues by 1–153%, with the most pronounced effects observed when applied at the seedling stage. Following lime application at different stages, Cd concentrations in all rice tissues showed a decreasing trend. Compared to CK (without lime application), Cd concentrations decreased by 2–26% in roots, 33–80% in stems, and 8–62% in grains. Among the treatments, LS was the most effective in reducing Cd levels, while LT, LB, and LF exhibited progressively weaker reductions. Structural equation modeling indicated that soil pH and stem Cd concentrations were key factors influencing grain Cd accumulation. These findings demonstrate that lime application at the early seedling stage is most effective in mitigating Cd uptake by rice, providing a practical strategy for safe rice production in Cd-contaminated soils. Full article

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25 pages, 15379 KB

Open AccessArticle

Improving Digital Soil Organic Carbon Mapping Using Continuum-Removal Spectral Indices and Multivariate Geostatistics

by Gabriele Buttafuoco, Carmela Riefolo, Massimo Conforti and Annamaria Castrignanò

Soil Syst. 2026, 10(2), 29; https://doi.org/10.3390/soilsystems10020029 - 12 Feb 2026

Cited by 1 | Viewed by 1288

Abstract

This study aimed to evaluate the effectiveness of spectral absorption-feature indices, derived from soil hyperspectral diffuse reflectance spectroscopy, as covariates within a multivariate geostatistical framework to enhance the digital mapping of soil organic carbon (SOC). The approach also incorporated exhaustively measured auxiliary variables [...] Read more.

This study aimed to evaluate the effectiveness of spectral absorption-feature indices, derived from soil hyperspectral diffuse reflectance spectroscopy, as covariates within a multivariate geostatistical framework to enhance the digital mapping of soil organic carbon (SOC). The approach also incorporated exhaustively measured auxiliary variables derived from topographic and textural attributes. The research was conducted in a 1.39-km² forested catchment, where 135 topsoil samples (0–0.20 m depth) were collected from soils classified as Typic Xerumbrepts and Ultic Haploxeralfs. All samples were analyzed for SOC concentration, soil texture, and diffuse reflectance spectra across the VIS–NIR–SWIR region (350–2500 nm). The continuum-removal technique was applied to compute radiometric indices associated with absorption features in the visible region and at 1400, 1900, and 2200 nm. Results demonstrated that these indices effectively captured the SOC spatial variability when combined with silt fraction and topographic attributes, which, among the other covariates, actually exhibited the strongest spatial relationships with SOC. Compared to univariate ordinary kriging, the multivariate geostatistical approach yielded improved prediction accuracy in cross-validation, mostly due to the use of hyperspectral indices as auxiliary variables. Moreover, the geostatistical analysis revealed that the multivariate frame of spatial association was characterized by two distinct spatial scales. The findings of this work then support the use of hyperspectral indices as valuable covariates for digital modelling of SOC distribution even in landscapes characterized by heterogeneous topography and pedology. Full article

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

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13 pages, 815 KB

Open AccessArticle

Aboveground and Belowground Interactions of Botanical Species, Historical and Modern Cultivars of Barley (Hordeum vulgare L.) Supported by Mineral or Organic Fertilizers

by Masoud M. Ardestani, Kateřina Čápová, Filip Křivohlavý, Adnan Mustafa, Zdeněk Nesvadba and Jan Frouz

Soil Syst. 2026, 10(2), 28; https://doi.org/10.3390/soilsystems10020028 - 11 Feb 2026

Viewed by 1568

Abstract

While the effect of domestication on various aspects of plant ecophysiology has been studied, less is known about its effect on plant–soil interaction. Here, we studied three botanical species of barley in comparison with four old cultivars and four contemporary cultivars with bare [...] Read more.

While the effect of domestication on various aspects of plant ecophysiology has been studied, less is known about its effect on plant–soil interaction. Here, we studied three botanical species of barley in comparison with four old cultivars and four contemporary cultivars with bare soils and two perennial grasses. Aboveground and belowground biomass decreased from botanical species to old cultivars and contemporary cultivars. Aboveground biomass of all barley cultivars was about one third lower in mineral fertilizer compared to the organic one, and this difference was similar in all barley cultivars. Biomass of perennial grasses was up to one third of barley biomass, but grass biomass did not differ significantly between fertilization treatments. Belowground biomass of botanical barley is significantly higher than that of modern cultivars; this discrepancy is even more pronounced under mineral fertilizer where belowground biomass of botanical barley significantly increased, and that of modern cultivars significantly decreased in comparison with organic fertilizer treatment, which means that modern barley cultivar in combination with mineral fertilizers provides less belowground litter to soil. This in the long term can potentially, together with other factors, contribute to the depletion of cultivated soil for organic matter. Microbial respiration in soil did not differ between treatments supplied by organic fertilizer, while in mineral fertilizer treatments old cultivars had lower respiration than other treatments. Microbial biomass did not differ between treatments supplied by mineral fertilizer, but in treatments supported by organic fertilizer, perennial grasses supported more microbial biomass than all barley treatments. The same pattern was observed in C content in soil. Carbon distribution in individual soil fractions did not differ between perennial grasses and barley treatments. In general, when hotspots of organic matter were provided, plants transferred this organic matter to soil, and this activity was more pronounced in perennial grasses than in barley treatments. Full article

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17 pages, 951 KB

Open AccessArticle

Wheat Yield Responses to NPK Fertilizers and Nutrient Omissions for QUEFTS Model Validation in Tigray, North Ethiopia

by Shimbahri Mesfin, Mitiku Haile, Girmay Gebresamuel, Amanuel Zenebe, Abera Gebre, Okubay Giday Adhanom, Lars Olav Eik and Bal Ram Singh

Soil Syst. 2026, 10(2), 27; https://doi.org/10.3390/soilsystems10020027 - 10 Feb 2026

Cited by 1 | Viewed by 1536

Abstract

Improving crop productivity largely depends on understanding soil fertility constraints and the effects of nutrient management on yield performance. Accurate determination of existing soil nutrient status and targeted application of limiting nutrients are essential for enhancing wheat (Triticum spp.) productivity. However, the [...] Read more.

Improving crop productivity largely depends on understanding soil fertility constraints and the effects of nutrient management on yield performance. Accurate determination of existing soil nutrient status and targeted application of limiting nutrients are essential for enhancing wheat (Triticum spp.) productivity. However, the specific effects of omitting one of the macronutrients such as nitrogen (N), phosphorus (P), or potassium (K) on wheat yield have not been investigated in the target area. This study employed the Quantitative Evaluation of the Fertility of Tropical Soils (QUEFTS) model to estimate the N, P, and K fertilizer requirements needed to achieve a predefined wheat yield target. The objectives were to: (i) evaluate yield responses to complete versus nutrient omission (N, P, or K) fertilization treatments, and (ii) analyze corresponding nutrient uptake and use efficiency dynamics. The experimental treatments included: (1) full NPK fertilization, (2) NP only (K omitted), (3) NK only (P omitted), (4) PK only (N omitted), and (5) an unfertilized control. Topsoil samples were analyzed and used as inputs for the QUEFTS model. Yield and agronomic data, as well as nutrient uptake and use efficiency, were measured. Model performance was validated using standard statistical metrics. Results showed that full NPK application significantly (p < 0.05) improved yield, yield components, and nutrient uptake compared to omission treatments and the control. The strong agreement between QUEFTS-predicted and observed yields highlights the model’s potential as a reliable, cost-effective decision-support tool for optimizing site-specific fertilizer recommendations. These findings demonstrate that balanced NPK fertilization markedly boosts wheat yield and nutrient uptake, while the QUEFTS model provides a powerful, reliable tool for tailoring fertilizer management to local soil 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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32 pages, 3090 KB

Open AccessArticle

Interactive Effects of Tillage, Nitrogen Fertilisation, and Herbicide Management: Impacts on Soil CO₂ Emissions and Agroecosystem Dynamics in a Maize Production

by Zainulabdeen Kh. Al-Musawi, Agampodi Gihan S. D. De Silva, Jabir Ali Abdinoor, László Bede, Dávid Stencinger, Bálint Horváth, Sándor Zsebő, Áron Licskai, Gergő Hegedüs, Viktória Vona, Gyula Pinke, Bahar Makbule Temeltürk, Emőke Ruzsics and István Mihály Kulmány

Soil Syst. 2026, 10(2), 26; https://doi.org/10.3390/soilsystems10020026 - 5 Feb 2026

Viewed by 1510

Abstract

Agriculture must balance productivity with greenhouse gas emissions, biodiversity, and resource concerns. This study examined how tillage (conventional, CT; minimum, MT), nitrogen fertilisation (0–221 kg N ha⁻¹), and herbicide rates (0–100%) interactively affected soil CO₂ emissions, vegetation vigour, and weed [...] Read more.

Agriculture must balance productivity with greenhouse gas emissions, biodiversity, and resource concerns. This study examined how tillage (conventional, CT; minimum, MT), nitrogen fertilisation (0–221 kg N ha⁻¹), and herbicide rates (0–100%) interactively affected soil CO₂ emissions, vegetation vigour, and weed diversity in maize production during 2022. A factorial experiment was conducted on a 1 ha with 40 plots monitored soil temperature, moisture, penetration resistance, normalised difference vegetation index (NDVI), weed diversity (Simpson’s Index), and CO₂ emissions (closed-chamber method). Minimum tillage increased soil water retention (9.3 ± 6.5% vs. 5.4 ± 4.3%), soil temperature (28.0 ± 1.5), and compaction (0.6 ± 0.3 vs. 0.1 ± 0.0 MPa), while enhancing weed diversity (0.53–0.80 vs. 0.38–0.67). MT produced higher CO₂ emissions than CT, especially at 147 kg N ha⁻¹ (49.9 ± 15.7 vs. 29.1 ± 11.6 μmol m⁻² s⁻¹), peaking under MT-147 kg N ha⁻¹-H75 (79.4 ± 1.2 μmol m⁻² s⁻¹). NDVI responses varied between tillage systems; under CT, vegetation vigour peaked at 75% herbicide application, while under MT vegetation was more responsive to nitrogen and more sensitive to herbicide, highlighting nitrogen × herbicide interaction trade-offs. Overall, MT enhanced water conservation and weed diversity but increased short-term CO₂ emissions. This study reports first-year, site-specific results from an ongoing multi-year field experiment; therefore, the findings were interpreted as short-term, season-specific responses. This highlights the need for site-specific, climate-smart management that integrates emissions, soil health, biodiversity, and productivity. 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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30 pages, 6538 KB

Open AccessArticle

Combined Use of FTIR and Atomic Emission Spectroscopies for Wet-Sieved Fractions of Kastanozem Soils

by Olga B. Rogova, Dmitry S. Volkov and Mikhail A. Proskurnin

Soil Syst. 2026, 10(2), 25; https://doi.org/10.3390/soilsystems10020025 - 3 Feb 2026

Viewed by 1218

Abstract

FTIR spectroscopy, attenuated total reflection (ATR), and diffuse reflectance (DRIFT) modalities, along with ICP–AES spectroscopy and correlation analysis, including two-dimensional correlation spectroscopy (2DCOS), were used for the detailed analysis of Kastanozem (chestnut) soils. Microaggregates (20–200 μm) and macroaggregates (200–1000 μm) of characteristic horizons [...] Read more.

FTIR spectroscopy, attenuated total reflection (ATR), and diffuse reflectance (DRIFT) modalities, along with ICP–AES spectroscopy and correlation analysis, including two-dimensional correlation spectroscopy (2DCOS), were used for the detailed analysis of Kastanozem (chestnut) soils. Microaggregates (20–200 μm) and macroaggregates (200–1000 μm) of characteristic horizons of uncultivated (fallow) and cultivated (arable land) chestnut soils of the same origin were physically fractionated by wet sieving. The combination of these molecular and atomic spectroscopy techniques in combination with correlation analysis was able to find direct correlations between matrix-forming anions and soil organic matter (SOM) of Kastanozems. Humic substances were separated from the corresponding soil samples to reveal SOM contributions more explicitly. Microaggregates of the size fractions of 20–40 μm and 40–60 μm bore the most comprehensive information for both techniques used. Most significant differences between land-use Kastanozem samples were observed in topsoil horizons (arable P versus light-colored humic AJ horizon), and for the next pair of horizons along the profile xerometamorphic BMK horizon to structural metamorphic BM horizon. These differences included carbonate matrix and SOM amounts and composition. Topsoil arable land showed significantly smaller amounts of total organic carbon and a decrease in the share of long-chain hydrocarbons compared to fallow, which has a more distinctive character compared to similar land-use samples of Chernozem. An increase in carbonate contents with soil depth was found for both land-use samples, while the amounts and composition of the silicate matrix remained largely unchanged within the depth profile. The heterospectral 2DCOS comparison of FTIR (between horizons and land-use samples), ICP–AES (between land-use samples), and FTIR–AES (for the same sample) showed the possibility of a more reliable attribution of FTIR absorption bands and revealed the differences in the macro- and micro-aggregate elemental and SOM composition of Kastanozems. Full article

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21 pages, 3729 KB

Open AccessArticle

The Variation and Driving Factors of Soil Organic Carbon Stocks and Soil CO₂ Emissions in Urban Infrastructure: Case of a University Campus

by Viacheslav Vasenev, Robin van Velthuijsen, Marcel R. Hoosbeek, Yury Dvornikov and Maria V. Korneykova

Soil Syst. 2026, 10(2), 24; https://doi.org/10.3390/soilsystems10020024 - 29 Jan 2026

Cited by 2 | Viewed by 1335

Abstract

The development of urban green infrastructures (UGI) is considered among the main nature-based solutions for climate mitigation in cities; however, the role of soils in the carbon (C) balance of UGI ecosystems remains largely overlooked. Urban green spaces are typically dominated by constructed [...] Read more.

The development of urban green infrastructures (UGI) is considered among the main nature-based solutions for climate mitigation in cities; however, the role of soils in the carbon (C) balance of UGI ecosystems remains largely overlooked. Urban green spaces are typically dominated by constructed Technosols, created by adding organic materials on top of former natural or agricultural subsoils. The combined effects of land-use history and current UGI management result in a high spatial variation of soil organic carbon (SOC) stocks and soil CO₂ emissions. Our study aimed to explore this variation for the case of Wageningen University campus. Developed on a former agricultural land, the campus area includes green spaces dominated by trees, shrubs, lawns, and herbs, with well-documented management practices for each vegetation type. Across the campus area (~32 ha), a random stratified topsoil sampling (n = 90) was conducted to map the spatial variation of topsoil (0–10 cm) SOC stocks. At the key sites (n = 8), representing different vegetation types and time of development (old, intermediate, and recent), SOC profile distribution was analyzed including SOC fractionation in surface and subsequent horizons, as well as the dynamics in soil CO₂ emissions, temperature, and moisture. Topsoil SOC contents on campus ranged from 1.1 to 5.5% (95% confidence interval). On average, SOC stocks under trees and shrubs were 10–15% higher than those under lawns and herbs. The highest CO₂ emissions were observed from soil under lawns and coincided with a high proportion of labile SOC fraction. Temporal dynamics in soil CO₂ emissions were mainly driven by soil temperature, with the strongest relation (R² = 0.71–0.88) observed for lawns. Extrapolating this relationship to the calendar year and across the campus area using high-resolution remote sensing data on surface temperatures resulted in a map of the CO₂ emissions/SOC stocks ratio, used as a spatial proxy for C turnover. Areas dominated by recent and intermediate lawns emerged as hotspots of rapid C turnover, highlighting important differences in the role of various UGI types in the C balance of urban green spaces. Full article

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19 pages, 1361 KB

Open AccessArticle

Role of Pedoagroclimate Settings in Enhancing Sorghum Production in Indonesia

by Yiyi Sulaeman, Nana Sutrisna, Joko Pramono, Lilia Fauziah, Ahmad Suriadi, Heppy Suci Wulanningtyas, Eni Maftu’ah, Endang Gati Lestari and Anny Mulyani

Soil Syst. 2026, 10(2), 23; https://doi.org/10.3390/soilsystems10020023 - 27 Jan 2026

Viewed by 1452

Abstract

Sorghum is a strategic crop for food, feed, and bioenergy. However, information on its cultivation area and agronomic profile in Indonesia remains limited. Therefore, this study aimed to identify, characterize, and evaluate sorghum cultivation in different agroecosystems and pedoagroclimatic settings in Indonesia. We [...] Read more.

Sorghum is a strategic crop for food, feed, and bioenergy. However, information on its cultivation area and agronomic profile in Indonesia remains limited. Therefore, this study aimed to identify, characterize, and evaluate sorghum cultivation in different agroecosystems and pedoagroclimatic settings in Indonesia. We surveyed published articles, newspapers, and other digital resources, collating a dataset that contained pedoagroclimatic characteristics. We then conducted a field survey to gather data on sorghum farming practices. The results show that sorghum is planted in 11 agroclimatic zones, mainly in D3, B1, and E4, and in seven soil types, mainly in Inceptisols, Mollisols, Vertisols, and Andisols. The cultivated varieties cover Bioguma 1, Bioguma 2, Bioguma 3, Numbu, Kawali, UPCA-S1, Suri 3 Agritan, Soper 9, and local varieties. Under smallholder farmers’ management, the average sorghum yield ranges from 3.6 to 7.5 Mg ha⁻¹. The 15–68% of the yield gap can be closed by implementing site-specific technologies, including high-yielding varieties and soil management. These findings provide a baseline for supporting efforts to increase sorghum production and develop robust sorghum cultivation technologies. 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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21 pages, 2930 KB

Open AccessArticle

Residual Effects of Wood Ash, Biochar, and Paper Mill Sludge on Crop Yield and Soil Physico-Chemical Properties

by Bernard Gagnon and Noura Ziadi

Soil Syst. 2026, 10(2), 22; https://doi.org/10.3390/soilsystems10020022 - 26 Jan 2026

Cited by 2 | Viewed by 1579

Abstract

The application of forest byproducts to cropland provides significant benefits, mitigating soil degradation, supplying essential nutrients, and increasing yields. Their impact is well known in the first years, but few studies have examined the effects several years after an application. A field study [...] Read more.

The application of forest byproducts to cropland provides significant benefits, mitigating soil degradation, supplying essential nutrients, and increasing yields. Their impact is well known in the first years, but few studies have examined the effects several years after an application. A field study was initiated in Québec, QC, Canada, to assess the effects of wood ash (10 and 20 Mg dry wt. ha⁻¹), pine biochar (10 Mg dry wt. ha⁻¹), paper mill sludge (PS) (12 Mg dry wt. ha⁻¹), and a combination of wood ash and PS, relative to an untreated control and a mineral treatment, on crop yield and soil properties three to seven years after application in a temperate circumneutral loamy soil. The site was cropped to a maize (Zea mays L.)–soybean [Glycine max (L.) Merr.]–spring wheat (Triticum aestivum L.) rotation. Each crop received supplemental N and P from mineral fertilizers, when needed, according to local agronomic recommendations. Applying wood ash increased wheat yield by 0.25–0.44 Mg ha⁻¹ three years after the addition, but no effect was detected in other cases and for the other amendments. Wood ash also resulted in the largest increases (p < 0.05) in soil pH and Mehlich-3 P, K, Ca, Mg, Zn, and Cd, alone or in combination with PS. Pine biochar promoted soil C sequestration after seven years, but did not affect other soil properties owing to its high stability and low nutrient content. This study revealed that wood ash was more advantageous than pine biochar for improving soil quality and crop productivity. Full article

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21 pages, 5185 KB

Open AccessArticle

Short-Term Effects of Biochar on Soil Fluxes of Methane, Carbon Dioxide, and Water Vapour in a Tea Agroforestry System

by Md Abdul Halim, Md Rezaul Karim, Nigel V. Gale and Sean C. Thomas

Soil Syst. 2026, 10(2), 21; https://doi.org/10.3390/soilsystems10020021 - 24 Jan 2026

Cited by 2 | Viewed by 1274

Abstract

Tea (Camellia sinensis) cultivation is a major global industry that faces sustainability challenges due to soil degradation and greenhouse gas (GHG) emissions from intensive management. Biochar—charcoal designed and used as a soil amendment—has emerged as a potential tool to improve soil [...] Read more.

Tea (Camellia sinensis) cultivation is a major global industry that faces sustainability challenges due to soil degradation and greenhouse gas (GHG) emissions from intensive management. Biochar—charcoal designed and used as a soil amendment—has emerged as a potential tool to improve soil health, enhance carbon sequestration, and mitigate GHG fluxes in agroecosystems. However, field-scale evidence of its effects on GHG dynamics in woody crops like tea remains limited, particularly regarding methane (CH₄). Here, we present, to our knowledge, the first field assessment of biochar impacts on CO₂, CH₄, and H₂O vapour fluxes in a subtropical tea agroforestry system with and without shade trees in northeastern Bangladesh. Using a closed dynamic chamber and real-time gas analysis, we found that biochar application (at 7.5 t·ha⁻¹) significantly enhanced average soil methane (CH₄) uptake by 84%, while soil respiration (CO₂ efflux) rose modestly (+18%) and water-vapour fluxes showed a marginal increase. Canopy conditions modulated these effects: biochar strongly enhanced CH₄ uptake under both shaded and open canopies, whereas biochar effects on water-vapour flux were detectable only when biochar was combined with a shade-tree canopy. Structural equation modelling suggests that CH₄ flux was primarily governed by biochar-induced changes in soil pH, moisture, nutrient status, and temperature, while CO₂ and H₂O fluxes were shaped by organic matter availability, temperature, and phosphorus dynamics. These findings demonstrate that biochar can promote CH₄ uptake and alter soil carbon–water interactions during the dry season in tea plantation systems and support operational biochar use in combination with shade-tree agroforestry. Full article

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

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Soil Syst., Volume 10, Issue 2 (February 2026) – 14 articles

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