Search Results (377)

Salinization is a growing global problem, particularly in arid and semi-arid areas, where salt concentration interferes with the soil structure, altering natural cycling, decreasing agricultural outputs, and threatening food security. Although many soil amendments have been studied, there is still a limited understanding of their interaction with soil after mixture application and the geochemical processes and long-term sustainability that govern their effects. To address this knowledge gap, this review elucidated the effectiveness and sustainability of soil amendments, biochar, humic substances, and mineral additives in restoring saline and sodic soils of arid and semi-arid region to explore the geochemical processes that underlie their impact. A systematic search of 174 peer-reviewed studies was conducted across multiple databases (Web of Science, Google Scholar, and Scopus) using relevant keywords and the findings were converted into quantitative values to evaluate the effects of biochar, gypsum, zeolite, and humic substances on key soil properties. Biochar significantly improved cation exchange capacity, nutrient retention, microbial activity, and water retention by enhancing soil porosity and capillarity, thereby increasing plant-available water. Gypsum improved phosphorus availability, while zeolite facilitated the removal of sodium and supported microbial activity. Humic substances enhanced soil porosity, water retention, and aggregate stability. When applied together, these amendments improved soil health by regulating salinity, enhancing nutrient cycling, while also stabilizing soil conditions and ensuring long-term sustainability through improved geochemical balance and reduced environmental impacts. The findings highlight the critical role of multi-functional amendments in promoting climate-resilient agriculture and long-term soil health restoration in saline-degraded regions. Further research and field implementation are crucial to optimize their effectiveness and ensure sustainable soil management across diverse agricultural environments. Full article

Antibiotic resistance genes (ARGs) pose a serious threat to the environment worldwide. The guts of soil animals are a hotspot for ARGs and denitrification in soils. However, it is unclear how denitrification affects the spread of ARG in the earthworm’s gut. In this study, the typical soil earthworm Pheretima guillelmi was employed, and was used for performing anoxic incubation with gut content amended with nitrate and nitrite. To analyze the data, a combination of chemical analysis, 16S rRNA-based Illumina sequencing, and high-throughput qPCR were employed. Nitrate treatments, particularly at 5 mM, caused substantial reductions in nitrate concentrations, with a corresponding increase in nitrite, nitrous oxide (N₂O), and nitric oxide (NO) emissions compared to the treatments with the addition of 1 and 2 mM nitrate. Nitrite (0.2, 0.5 and 1 mM) amendments also enhanced the accumulation of nitrogen intermediates. Organic acid production, including acetate and pyruvate, was the highest under the 5 mM nitrate treatment. This treatment also promoted the highest level of glucose utilization, suggesting that glucose metabolism supports enhanced organic acid production. Both nitrate and nitrite treatments exhibited the pronounced enrichment in ARGs, particularly for beta-lactam and multidrug resistance genes. Denitrifying bacteria such as Aeromonas, Bacillus, Raoultella, and Enterobacter were identified as key hosts for these ARGs. These results emphasized that denitrifying bacteria play a pivotal role in the horizontal transfer of ARGs, underscoring the need for careful nitrogen management in agricultural practices to control the spread of antibiotic resistance in natural environments. Full article

Long-term continuous cropping is a prevalent agricultural practice aimed at maximizing land use efficiency and crop yields, yet it often leads to severe soil degradation, nutrient imbalance, and microbial community disruption. Effective soil remediation strategies are urgently needed to restore soil health and ensure sustainable agricultural production. In this study, we investigated the impact of forest soil amendment on microbial community structure, diversity, and functional potential in long-term continuous cropping soils. Using metagenomic sequencing, we analyzed soils from natural forest (BK), forest soil-amended soils (BCP), and fields under continuous cropping for 15 years (CP15) and 30 years (CP30). Forest soil amendment significantly mitigated microbial diversity loss and structural degradation caused by prolonged monoculture. Alpha diversity analysis revealed that BCP restored microbial diversity to levels comparable to BK, while beta diversity and NMDS analyses showed that microbial community composition in BCP closely resembled that of forest soil. Taxonomic profiling indicated that forest soil amendment enriched beneficial taxa such as Actinobacterota and Acidobacteriota, reversing shifts observed in CP15 and CP30. Functionally, COG and KEGG annotations revealed that BCP soils exhibited higher abundances of genes involved in carbohydrate metabolism, energy production, and nutrient cycling. Notably, the amendment reduced antibiotic resistance genes and virulence factors, potentially improving the microbial risk profile of soil communities. These findings demonstrate that forest soil amendment effectively restores microbial community structure and functionality in degraded soils, providing a nature-based solution for sustainable agriculture. Full article

This study investigates the impact of tire wear particles (TWPs) and their dissolved organic matter (DOM) on soil DOM dynamics and heavy metal behavior. Through short-term incubation experiments under simulated natural conditions with TWPs of varying particle sizes, we analyzed ecological changes in soil. Using three-dimensional excitation–emission matrix (3D-EEM) spectroscopy coupled with parallel factor analysis, we monitored the photochemical properties and compositional evolution of soil dissolved organic matter. Results demonstrate that TWP amendment substantially alters soil DOM molecular characteristics, inducing a sharp decrease in protein-, carbohydrate-, and lipid-like components, the degradation of low-aromaticity unstable dissolved organic matter, and an overall increase in aromaticity. Furthermore, TWP input directly modified soil properties, triggering the transformation of soil aggregates: the proportion of large aggregates significantly decreased while that of small aggregates increased, thereby reducing overall aggregate stability. The bioaccessibility of heavy metals (HMs) (Cd, Cu, and Zn) extracted by CaCl₂ increased, primarily due to the release of endogenous metals from TWPs, compounded by the disruption of soil aggregates. In contrast, Pb tended to transform into more stable fractions under TWP stress, reducing its bioaccessibility. Further correlation analysis indicated that TWPs indirectly affected HM (Cd, Cu, and Zn) fractionation by influencing the soil dissolved organic matter properties and soil properties. This study provides a new perspective for elucidating the interplay between dissolved organic matter and HMs in urban soils, as mediated by tire wear particles (TWPs). Full article

Natural humus, characterized by its high organic carbon content and high degree of humification, is widely used in soil improvement. However, the impact of natural humus on the multifunctionality of saline–alkali soils and its relationship with soil microbial diversity remain poorly understood. This study conducted experiments with varying concentrations of natural humus to explore changes in soil multifunctionality and its driving factors. The results indicate that the addition of natural humus increases soil organic matter (by 23.5–45.73%) and alkali-hydrolyzable nitrogen (by 40–81.57%), while reducing electrical conductivity (by 1.8–35.9%). These changes enhance soil microbial diversity and improve soil multifunctionality. As natural humus is a high C/N material, nitrogen limitation in soil microorganisms may occur with increasing humus addition. However, the increase in K-strategy fungi (which are more efficient in resource utilization) helps maintain a relatively high level of soil multifunctionality. At the maximum application rate (30 t/ha), soil multifunctionality reached its peak value of 0.41. These findings highlight the significant role of natural humus in improving saline–alkali soils and enhancing soil functions, particularly through its effects on microbial communities, especially K-strategy fungi. Full article

Aquaculture is the fastest-growing food production sector globally. As its largest producer, China plays a pivotal role in ensuring aquatic food supply and supporting the blue economy. Despite its massive scale, a systematic understanding of the geographic distribution, structural composition, and drivers of China’s aquaculture value chain remains limited. We comprehensively characterized the sector’s composition, spatiotemporal evolution, and structural dynamics. We compiled and analyzed over 2.85 million enterprise registration records from the TianYanCha database, applying rigorous industry classification, spatial mapping, correlation analysis, and bottleneck assessment with natural and socioeconomic variables. Results show that policy reforms, notably the 2013 Company Law amendment and 2016 aquaculture certification measures, drove sharp increases in enterprise registrations, particularly in retail and farming. Enterprises are highly clustered in the Yangtze River Basin, Pearl River Delta, and southeastern coast, with inland expansion along major river systems. Strong interdependencies exist among sectors, while wholesale remains numerically scarce, forming a structural bottleneck. Standardization levels are low. Foreign investment, though under 5%, concentrated in processing and distribution, contributed to advanced technologies in the 1990s–2000s. These findings highlight rapid formalization, regional clustering, and structural imbalances, suggesting that enhancing formalization and addressing intermediary bottlenecks could improve sector resilience and efficiency. Full article

This study evaluated the seasonal greenhouse gas (GHG) emissions and carbon assimilation of Bambusa edulis under four soil amendment treatments—control (C), biochar (B), fertilizer using vermicompost (F), and biochar plus fertilizer (B + F)—in a coastal shelterbelt system in south-western Taiwan. Over a 12-month period, CO₂ and N₂O fluxes and photosynthetic carbon uptake were measured. The control (C) treatment served as the baseline, exhibiting the lowest greenhouse gas (GHG) emissions and carbon assimilation. Its summer N₂O emissions were 39.54 ± 20.79 g CO₂ e m⁻², and its spring carbon assimilation was 13.2 ± 0.84 kg CO₂ clump⁻¹. In comparison, the amendment treatments significantly enhanced both emissions and carbon uptake. The fertilizer-only (F) treatment resulted in the highest levels, with peak summer N₂O emissions increasing by 306.5% (to 160.73 ± 96.22 g CO₂ e m⁻²) and spring carbon assimilation increasing by 40.2% (to 18.5 ± 0.62 kg CO₂ clump⁻¹). An increase in these values was also observed in the combined biochar and fertilizer (B + F) treatment, although the magnitude was less than that of the F treatment alone. In the B + F treatment, summer N₂O emissions increased by 130.3% (to 91.1 ± 62.51 g CO₂ e m⁻²), while spring carbon assimilation increased by 17.4% (to 15.5 ± 0.36 kg CO₂ clump⁻¹). Soil CO₂ flux was significantly correlated with atmosphere temperature (r = 0.63, p < 0.01) and rainfall (r = 0.45, p < 0.05), while N₂O flux had a strong positive correlation with rainfall (r = 0.71, p < 0.001). The findings highlight a trade-off between nutrient-driven productivity and GHG intensity and demonstrate that optimized organic and biochar applications can enhance photosynthetic carbon gain while mitigating emissions. The results support bamboo’s role in climate mitigation and carbon offset strategies within nature-based solution frameworks. Full article

Biological soil amendments of animal origin (BSAAOs) provide risk for foodborne contamination. Soils are often enriched with BSAAOs to increase nutrient value, enhance and support crop growth and yield. Little is known about the interactions of soil microorganisms and the potential impact on food safety. Although BSAAOs provide benefits to soil and crops, BSAAOs are a risk for contamination. Another source of risk includes adjacent land use of concentrated animal feed operations (CAFOs) and the risk of contaminated dust with pathogens such as Escherichia coli or Salmonella is becoming more of a concern. Studies have shown that crops planted adjacent to a cattle feedlot were contaminated with pathogenic E. coli O157:H7 which originated from the cattle feedlot. Further research is needed to evaluate novel bioremediation techniques to lower/prevent the risks of windborne contamination of dust and risks posed by untreated BSAAOs. One potential novel technique is the utilization of mycofiltration. The risks of pathogenic contamination of BSAAOs could be reduced by developing a cost-effective and sustainable mycofiltration practice using naturally formulated by-products from filamentous fungi. Ligninolytic white-rot fungi can degrade a wide variety of toxic or persistent environmental contaminants and degrade pollutants in the environment. Recent studies have shown that white-rot fungi can inhibit pathogenic E. coli in bioreactor systems. Exploring white-rot fungi as a biocontrol agent for on-farm mycofiltration may prove to be a cost-effective treatment and limit certain routes of contamination to the edible portion of the crop, certainly worthy of exploration in this review. Full article

Substrate amendment is a promising strategy to enhance phytoremediation in degraded coastal wetlands, yet the selection of optimal materials and their incorporation ratios remains challenging. This study systematically investigated the effects of five amendments, viz., manganese sand, maifan stone, bentonite, iron–carbon (Fe-C), and vermiculite, across an incorporation ratio gradient (5–40%) on the growth of the mangrove, Kandelia obovata, and the physicochemical properties of coastal wetland substrate. Results demonstrated material-specific and dose-dependent responses. Four amendments (vermiculite, Fe-C, manganese sand, and maifan stone) promoted Kandelia obovata growth to varying degrees, while bentonite exhibited significant inhibition. All amendments ensured the physical stability of the substrate. Nutrient removal efficiency followed the order: Fe-C > vermiculite > maifan stone > manganese sand, with 10% Fe-C showing the highest comprehensive nutrient removal. Conversely, bentonite functioned as a nutrient enrichment agent. The amendments differentially influenced redox potential, CO₂ emissions, and electrical conductivity, yet all maintained a stable substrate pH. A comprehensive evaluation considering plant growth, nutrient removal, and CO₂ sequestration identified maifan stone as the optimal amendment, with the 40% incorporation ratio delivering the most favorable integrated performance. This study provides critical, ratio-specific guidance for selecting and applying substrate amendments in coastal wetland restoration. This study provides critical, ratio-specific guidance for selecting and applying environmentally sustainable amendments, supporting the development of nature-based solutions for long-term coastal wetland restoration. Full article

Studies have shown that natural organic matter can regulate pollutant behavior through multiple pathways; however, research on the environmental behavior of veterinary antibiotics (VAs) in typical alkaline calcareous loess soil under the influence of exogenous organic matter remains limited. This study investigated the influence of humic acid (HA), as a representative of natural organic matter, on the sorption behavior of ciprofloxacin (CIP) in sierozem—a typical alkaline calcareous loess soil. Using the batch equilibrium method, we examined how HA affects CIP sorption under various environmental conditions to better understand the environmental fate of VAs in soil–water systems with low organic matrix content. Results showed that CIP sorption onto sierozem involved both fast and slow processes, reaching equilibrium within 2 h, with sorption capacity increasing as HA concentration increased. Kinetic data were well described by the pseudo-second-order model regardless of HA addition, suggesting multiple mechanisms governing CIP sorption, such as chemical sorption reaction, intraparticle diffusion, film diffusion, etc. Sorption decreased with increasing temperature both before and after HA amendment, indicating an exothermic process. Isotherm analysis revealed that both the Linear and Freundlich models provided excellent fits (R² ≈ 1), implying multilayer sorption dominated by hydrophobic distribution. In ion effect experiments, cations at concentrations above 0.05 mol/L consistently inhibited CIP sorption, with inhibition strength following the order: Mg²⁺ > K⁺ > Ca²⁺ > NH₄⁺, and intensifying with increasing ionic strength. However, HA addition significantly mitigated this inhibition, likely due to complexation between HA’s functional groups (e.g., carboxyl and hydroxyl) and cations, which reduced their competitive effect and enhanced CIP sorption. pH-dependent experiments indicated stronger CIP sorption under acidic conditions. HA addition increased soil acidity, further promoting CIP retention. In summary, HA enhances CIP sorption in sierozem by providing additional sorption sites and modifying soil surface properties. These findings improve our understanding of how exogenous organic matter influences the behavior of emerging contaminants such as antibiotics in soil–water systems, offering valuable insights for environmental risk assessment in semi-arid agricultural regions. Full article

Cadmium (Cd) accumulation in cocoa poses a regulatory challenge for cacao producers in regions with naturally elevated soil Cd, such as Indonesia. This study evaluated the potential of soil-based and plant-based solutions to reduce Cd uptake in cacao. The efficacy of soil amendments was tested with two experiments: (1) a 12-week soil incubation tested lime, biochar, and lime–biochar mixtures at five rates on sandy clay loam and (2) a field trial evaluating zeolite applied at three rates (300, 600, and 900 kg ha⁻¹) with heat or alkali pretreatments. A third experiment evaluated the potential of four cacao genotypes and their rootstock–scion interactions to mitigate Cd uptake over the course of a 12-month nursery trial in Cd-augmented soil. In the incubation study, some lime and biochar treatments produced numerically lower soil Cd concentrations than the control (0.25 mg kg⁻¹), with final means as low as 0.15 mg kg⁻¹, but these differences were not statistically significant in this experiment. Application of zeolite in the field significantly reduced leaf and bean Cd levels (leaf: 0.35–0.50 mg kg⁻¹; bean: 0.25–0.75 mg kg⁻¹) compared to the control (p < 0.01). In the nursery experiment, average increases in leaf Cd concentrations from 6 to 12 months after spiking were lowest in rootstock MCC01 (1.46 mg kg⁻¹; p < 0.001) compared to higher increases in MCC02 (4.16 mg kg⁻¹) and Sulawesi 1 (3.53 mg kg⁻¹), indicating reduced Cd uptake by MCC01 across scions, while scion and interaction effects were not significant. Targeted soil amendments and specific rootstock–scion combinations are promising strategies to reduce Cd concentrations in cacao systems. Full article

Green coconut husk is an abundant and underutilized agro-industrial residue in Brazil, contributing significantly to landfill overload. This study investigates the pyrolysis of pellets derived from this biomass as a technological alternative for its valorization, focusing on the integrated characterization of the three resulting products. Pellets were subjected to pyrolysis in a fixed-bed reactor under two distinct conditions: at 400 °C to maximize biochar production, and at 600 °C to enhance gas generation. The raw material and resulting solid, liquid, and gaseous fractions were characterized using physicochemical, thermal, morphological, and chromatographic analyses. Pyrolysis at 400 °C yielded biochar with high fixed carbon content (67.03%) and elevated heating value (27.80 MJ/kg), suitable for soil amendment and carbon sequestration. At 600 °C, the non-condensable gas exhibited a higher hydrogen concentration (35.84%) and an H₂/CO ratio of 1.84, favorable for chemical synthesis applications. Notably, palletization resulted in a significant bio-oil and gas yield even under 400 °C. The bio-oil underwent chemical upgrading, which significantly increased the phenolic content and raised its heating value to 20.40 MJ/kg. Additionally, combustion tests revealed that the gas produced emitted lower levels of NOx compared to natural gas. Full article

Soil aggregate stability is a key indicator of soil health and is fundamental to soil processes such as water infiltration, nutrient cycling, carbon sequestration, erosion control, and ecosystem functionality. However, research concerning the impact of natural and anthropogenic factors on SAS across different climates, soil types, and management practices is lacking. This review synthesizes current understanding of physical, chemical, and biological mechanisms that govern the aggregate formation and stability and brings to light how the natural and anthropogenic drivers influence these processes. It highlights how clay mineralogy, root systems, microbial diversity, soil organic matter, and management practices shape the structure and turnover of aggregates essential for agricultural productivity. Key drivers of aggregate formation, categorized into natural (such as texture, clay mineral interaction, biota, and climate) and anthropogenic (such as tillage, land use changes, organic amendments) factors, have been critically evaluated. This review provides an insightful framework for soil management that may help enhance soil aggregation and promote sustainable agriculture and food security, especially under climate change. Full article

Sodium carboxymethyl cellulose (Na-CMC) was used to improve the chemical compatibility of natural sodium bentonite (NaB) used in vertical cutoff walls for containing acid mine drainage (AMD). Ab Na-CMC content from 2% to 15% was examined to determine the minimum Na-CMC content of sodium carboxymethyl cellulose-amended bentonite (CMCAB) needed to yield a low hydraulic conductivity (<10⁻⁹ m/s). Hydraulic conductivity (k), swell index, viscosity, XRD spectra, FT-IR spectra, and microstructures were measured for CMCAB to assess the hydraulic performance of CMCAB for containing AMD and to elucidate the mechanism of reduced k due to the addition of Na-CMC. The results show that the k of CMCAB decreased with the increase in Na-CMC content and stress. A 10% or higher content of Na-CMC is required to reduce the k of NaB down to 10⁻⁹ m/s. Na-CMC did not impact the interlayer structure of NaB but increased the viscosity of CMCAB. CMCAB with increased viscosity retained the Na-CMC within the pore spaces, narrowing the flow paths for AMD and yielding low k. Full article

Understanding how carbon is stored and stabilized in temperate agricultural soils is central to addressing one of the defining environmental challenges of our time—climate change. In this review, we bridge quantitative bibliometric insights with a qualitative synthesis of the mechanisms, regional differences, management practices, and models governing soil organic carbon (SOC) dynamics. We systematically analyzed 481 peer-reviewed publications published between 1990 and 2024, retrieved from Scopus and Web of Science, using bibliometric tools such as VOSviewer to map research trends, collaboration networks, and thematic evolution. The bibliometric analysis revealed a marked increase in publications after 2010, coinciding with growing global interest in climate-smart agriculture and carbon sequestration policies. Comparative synthesis across temperate sub-regions—such as the humid temperate plains of Europe, the semi-arid temperate zones, and the temperate black soil region of Northeast China—reveals that the effectiveness of common practices varies with soil mineralogy, texture, moisture regimes, and historical land-use. Reduced tillage (average SOC gain of 0.25 Mg C ha⁻¹ yr⁻¹), cover cropping (0.32 Mg C ha⁻¹ yr⁻¹), and organic amendments such as compost and biochar (up to 1.1 Mg C ha⁻¹ yr⁻¹) consistently enhance SOC accumulation, but with region-specific outcomes driven by these contextual factors. Recognizing such heterogeneity is essential for developing regionally actionable management recommendations. Recent advances in machine learning, remote sensing, and process-based modeling are enabling more accurate and scalable monitoring of SOC stocks, yet challenges remain in integrating micro-scale stabilization processes with regional and global assessments. To address these gaps, this review highlights a multi-method integration pathway—combining field measurements, mechanistic modeling, data-driven approaches, and policy instruments that incentivize adoption of evidence-based practices. By combining quantitative bibliometric analysis with regionally informed mechanistic synthesis, this review provides a holistic understanding of how knowledge about SOC in temperate agroecosystems has evolved and where future opportunities lie. The findings underscore that temperate agricultural soils, when supported by appropriate scientific practices and enabling policy frameworks, represent one of the most accessible natural climate solutions for advancing climate-resilient and sustainable food systems. Full article