Soil Accumulation Research Articles

Nano-Iron Oxide (Fe3O4) Mitigates the Effects of Microplastics on a Ryegrass Soil-Microbe-Plant System.

To understand microplastic-nanomaterial interactions in agricultural systems, a randomized block 90-day pot experiment was set up to cultivate ryegrass seedings in a typical red sandy soil amended with compost (1:9 ratio). Polyvinyl chloride (PVC) and polyethylene (PE) microplastic (MP) contaminants were added into pot soils at 0.1 and 10%, whereas nano-Fe3O4 (as nanoenabled agrochemicals) was added at 0.1% and 0.5% in comparison with chemical-free controls. The combination of nano-Fe3O4 and MPs significantly increased the soil pH (+3% to + 17%) but decreased the total nitrogen content (-9% to - 30%; P < 0.05). The treatment group with both nano-Fe3O4 and PE had the highest total soil C (29 g kg-1 vs 20 g kg-1 in control) and C/N ratio (13 vs 8 in control). Increased rhizosphere nano-Fe3O4 concentrations promoted ryegrass growth (+42% dry weight) by enhancing the chlorophyll (+20%) and carotenoid (+15%) activities. Plant leaf and root peroxidase enzyme activity was more significantly affected by nano-Fe3O4 with PVC (+15%) than with PE (+6%). Nano-Fe3O4 significantly changed the ryegrass bacterial community structure from belowground (the rhizoplane and root endosphere) to aboveground (the phylloplane). Under MP contamination, the addition of nano-Fe3O4 increased bacterial diversity (+0.35%) and abundance (+30%) in the phylloplane and further intensified the connectivity of ryegrass aboveground bacterial networks (positive association increased 17%). The structural equation model showed that the change in the plant microbiome was associated with the rhizosphere microbiome. Overall, these findings imply the positive influences of nano-Fe3O4 on the soil-microbe-plant system and establish a method to alleviate the harmful effects of MP accumulation in soils.

Cadmium accumulation in tropical island paddy soils: From environment and health risk assessment to model prediction

Cultivated soil quality is crucial because it directly affects food safety and human health, and rice is of primary concern because of its centrality to global food networks. However, a detailed understanding of cadmium (Cd) geochemical cycling in paddy soils is complicated by the multiple influencing factors present in many rice-growing areas that overlap with industrial centers. This study analyzed the pollution characteristics and health risks of Cd in paddy soils across Hainan Island and identified key influencing factors based on multi-source environmental data and prediction models. Approximately 27.07% of the soil samples exceeded the risk control standard screening value for Cd in China, posing an uncontaminated to moderate contamination risk. Cd concentration and exposure duration contributed the most to non-carcinogenic and carcinogenic risks to children, teens, and adults through ingestion. Among the nine prediction models tested, Extreme Gradient Boosting (XGBoost) exhibited the best performance for Cd prediction with soil properties having the highest importance, followed by climatic variables and topographic attributes. In summary, XGBoost reliably predicted the soil Cd concentrations on tropical islands. Further research should incorporate additional soil properties and environmental variables for more accurate predictions and to comprehensively identify their driving factors and corresponding contribution rates.

Numerical investigation on lateral monotonic and cyclic responses of scoured rigid monopile based on an integrated bounding surface model

Offshore wind turbines (OWTs) are affected by wind, wave, and current during their service life, which lead to the substructures undergoing combined effects of complex lateral loads and local scour. This phenomenon poses a significant challenge to the bearing capacity and cyclic responses of the widely used rigid monopiles for OWTs. This study develops three-dimensional numerical model to investigate the behavior of a rigid monopile subjected to lateral monotonic and cyclic loads, considering the stress history alteration induced by local scour. The hysteresis and plasticity accumulation of soils are captured by a bounding surface model. An accurate and concise semi-implicit stress integration scheme is creatively proposed to effectively incorporate this advanced constitutive model into the finite element (FE) software. The numerical model is verified by comparing FE results with centrifuge test results. Subsequently, the key factors such as cumulative deformation characteristics and bending moments distribution are investigated under different scour and cyclic loading conditions. The results indicate that with the facilitation of proposed semi-implicit scheme, the bounding surface model is capable of capturing the deformation pattern and cumulative deformation behavior of laterally loaded rigid monopile, and the cyclic responses of the monopile are significantly affected by the local scour.

Integrated pollution analysis, pollution area identification and source apportionment of heavy metal contamination in agricultural soil

Given the global prevalence of soil heavy metal contamination, knowledge concerning of soil environmental quality assessment, pollution area identification and source apportionment is critical for implementation of soil pollution prevention and safe utilization strategies. In this study, soil static environmental capacity (QI) for heavy metals was selected to evaluate pollution risks in agricultural soils of Wenzhou, southeast China. Combined with geostatistical methods, the pollution area was identified along with uncertainty analysis. Potential sources were quantitatively apportioned using a positive matrix factorization model (PMF). Results showed that agricultural soils in this study were mainly contaminated by Cd and Pb based on both Nemerow and QI indices. The environmental capacity assessment found more than 90% areas were identified as polluted soils for Qi-Zn, Qi-Cd and Qi-Pb, with minor uncertain areas. Cu was identified as having a high proportion of uncertain pollution area status, which was similar to the results of the integrated environmental capacity for all metals. PMF results indicated that industrial discharge, agrochemicals and parent material accounted for 32.1%, 32.2% and 35.7% of heavy metal accumulation in soils, respectively. Implementation of strict policies to reduce anthropogenic source emissions and remediate soil pollution are crucial to minimize metal pollution inputs, improve agricultural soil quality and enhance food safety.

Climate and mineral accretion as drivers of mineral‐associated and particulate organic matter accumulation in tidal wetland soils

AbstractTidal wetlands sequester vast amounts of organic carbon (OC) and enhance soil accretion. The conservation and restoration of these ecosystems is becoming increasingly geared toward “blue” carbon sequestration while obtaining additional benefits, such as buffering sea‐level rise and enhancing biodiversity. However, the assessments of blue carbon sequestration focus primarily on bulk SOC inventories and often neglect OC fractions and their drivers; this limits our understanding of the mechanisms controlling OC storage and opportunities to enhance blue carbon sinks. Here, we determined mineral‐associated and particulate organic matter (MAOM and POM, respectively) in 99 surface soils and 40 soil cores collected from Chinese mangrove and saltmarsh habitats across a broad range of climates and accretion rates and showed how previously unrecognized mechanisms of climate and mineral accretion regulated MAOM and POM accumulation in tidal wetlands. MAOM concentrations (8.0 ± 5.7 g C kg−1) (±standard deviation) were significantly higher than POM concentrations (4.2 ± 5.7 g C kg−1) across the different soil depths and habitats. MAOM contributed over 51.6 ± 24.9% and 78.9 ± 19.0% to OC in mangrove and saltmarsh soils, respectively; both exhibited lower autochthonous contributions but higher contributions from terrestrial or marine sources than POM, which was derived primarily from autochthonous sources. Increased input of plant‐derived organic matter along the increased temperature and precipitation gradients significantly enriched the POM concentrations. In contrast, the MAOM concentrations depended on climate, which controlled the mineral reactivity and mineral–OC interactions, and on regional sedimentary processes that could redistribute the reactive minerals. Mineral accretion diluted the POM concentrations and potentially enhanced the MAOM concentrations depending on mineral composition and whether the mineral accretion benefited plant productivity. Therefore, management strategies should comprehensively consider regional climate while regulating sediment supply and mineral abundance with engineering solutions to tap the OC sink potential of tidal wetlands.

Analysis of Soiling Loss in Photovoltaic Modules: A Review of the Impact of Atmospheric Parameters, Soil Properties, and Mitigation Approaches

Soil accumulated on a photovoltaic (PV) module can significantly reduce the transmittance of the cover glass, resulting in power losses and consequent economic losses. Natural atmospheric parameters influence the accumulation of soil at various geographic locations. In this paper, the approaches and outcomes of the research studies on either indoor (simulator-based) or outdoor (field-based) PV soiling have been thoroughly reviewed. It has been noted that conducting an indoor study is necessary in order to estimate future power losses prior to the installation of a solar PV power plant. Different parameters depicted for the power loss due to the soiling of PV modules are analyzed individually and presented. Moreover, this study delves into a detailed examination of the key factors influencing dust depositions on PV modules in various geographical regions, with a particular focus on their relationship with climatic conditions. This study demonstrates that the soiling effect on PV modules is site-specific, necessitating the investigation of optimal cleaning procedures to suit a certain climate while considering cost effectiveness. This way, probable future research directions to quantify soiling losses are identified. In addition, different loss prevention and mitigation techniques are also reviewed. This makes it possible to highlight effective strategies and pinpoint potential future research lines in these areas.

Soil organic carbon stocks did not change after 130 years of afforestation on a former Swiss Alpine pasture

Abstract. Soil organic matter (SOM) plays an important role in the global carbon cycle, especially in alpine ecosystems. However, ongoing forest expansion in high-elevation systems potentially alters SOM storage through changes in organic matter (OM) inputs and microclimate. In this study, we investigated the effects of an Picea abies L. afforestation chrono-sequence (0 to 130 years) of a former subalpine pasture in Switzerland on soil organic carbon (SOC) stocks and SOM dynamics. We found that SOC stocks remained constant throughout the chrono-sequence, with comparable SOC stocks in the mineral soils after afforestation and previous pasture (SOC forest40 = 11.6 ± 1.1 kg m−2, SOC forest130 = 11.0 ± 0.3 kg m−2 and SOC pasture = 11.5 ± 0.5 kg m−2). However, including the additional carbon of the organic horizons in the forest, reaching up to 1.7 kg m−2 in the 55-year old forest, resulted in an increase in the overall SOC stocks following afforestation. We found that the soil C:N ratio in the mineral soil increased in the topsoil (0–5 cm) with increasing forest stand age, from 11.9 ± 1.3 in the pasture to 14.3 ± 1.8 in the 130-year old forest. In turn, we observed a decrease in the soil C:N ratio with increasing depth in all forest stand ages. This suggests that litter-derived organic matter (C:N from 35.1 ± 1.9 to 42.4 ± 10.8) is likely to be incorporated and translocated from the organic horizon to the mineral topsoil (0–10 cm) of the profiles. Due to the high root C:N ratio (pasture 63.5 ± 2.8 and forests between 54.7 ± 3.9 and 61.2 ± 2.9), particulate root-derived organic matter seems to have a rather small effect on forest soil C:N ratios, as well as on SOC accumulation in the mineral soil. These results suggest that, although afforestation does not change the SOC stock in the mineral soil, there is an apparent alteration in the SOM dynamics through changes in the litter composition caused by the vegetation shift. We conclude that, at our study site, spruce afforestation on a former subalpine pasture does not change the total SOC stock and that, consequently, there is no additional SOC sequestration on a decadal to centennial scale.

PREDICTION OF ENVIRONMENT STATE IMPACT IN AREA OF A COPPER-NICKEL PLANT ON THE BASIS OF BALANCED IDENTIFICATION TECHNOLOGY

The article deals with modeling the dynamics of nickel concentration in soils, water and bottom sediments of lakes, caused by emissions into the atmosphere of the Pechenganickel plant (Kola Peninsula) during the entire period of its operation. The technology of balanced identification is used, which allows, based on a mathematical description of heterogeneous geochemical processes occurring in ecosystems, to combine heterogeneous experimental data and build a computer model with an optimal balance of complexity and closeness to data. The results are presented and discussed, including estimates of the retrospective state of the simulated objects (before the start of intensive studies) and a forecast of their dynamics until 2030. According to model calculations, the intensity of Ni accumulation in soil was 2.4 and 2 times higher in bottom sediments during maximum precipitation periods (1980–2005), while according to the model forecast, after the shutdown of the plant, Ni accumulation in bottom sediments will begin to decrease and Ni will slowly leach from the soil with an intensity of 0.2 mg/m2 year.

Geochemical and Environmental Evaluation of the Copper Element in the Surface Soil and Its Health Effects in Selected Areas of Kirkuk Governorate

To assess the extent of copper contamination in the surface soil and its effects on human health in selected areas of Kirkuk Governorate, several geochemical analyzes and environmental assessments were performed. Twenty-two (22) surface soil samples were collected and analyzed using an inductively coupled plasma mass spectrometer. The results showed that the average concentration of copper in the study area was (42.64 ppm), and its highest value was in the (H19) site represented in the Benji Ali area (129.7 ppm). In (H11) site, with a concentration of (88.8 ppm), which represents an industrial neighborhood area, and the reason is due to it being a polluted industrial area, which is higher than the permissible natural values, amounting to (20 ppm). In the soil, the element copper, which indicates a potential danger to the environment, as well as the average values of the soil accumulation index showed that it is unpolluted to medium pollution, while the value of the average enrichment factor was medium enrichment, and also the average of the environmental hazard index showed potential moderate environmental risks, and it was found Exposure through inhalation (CDIinh) is more effective in adults and children with copper than through skin contact (CDIdermal) and ingestion (CDIing). And it was found that the values (HI) are greater than one for the studied copper element for both children and adults, which indicates The presence of carcinogenic health risks of the copper element on humans in the study area, and it was found that children are particularly vulnerable to the effects of copper because they are still developing.

Study on configurational operation strategy of ground heat exchangers under the effect of groundwater flow

In large-scale ground source heat pump (GSHP) systems, the accumulation of thermal energy resulting from seasonal load imbalances has emerged as a significant impediment. The implementation of a rational operation strategy can effectively mitigate heat accumulation in soil. This study investigates the impact of the configurational operation strategy for large-scale vertical ground heat exchanger (GHE) on the spatial distribution of ground temperature under the influence of groundwater flow. The internal heat source model is proposed to describe heat transfer process of GHE. Sandbox experiment is conducted to verify the model with maximum deviation of 3 %. The validated model is then utilized to simulate soil temperature profile in the large-scale GHE field over a 10-year operational period, considering a matrix of three configuration strategies and three operation strategies. The results shows that trapezoidal configurations combined with operation Strategy 3 has a minimal temperature increment of 2.9 °C in soil temperature. The contribution of this study lies in provision of a methodology for mitigating thermal accumulation in large-scale GHE field.

Accumulation of microplastics in soil after long-term application of biosolids and atmospheric deposition

Land-applied biosolids can be a considerable source of microplastics in soils. Previous studies reported microplastics accumulation in soils from biosolid application, however, little is known about the contribution of atmospherically deposited microplastics to agricultural soils. In this study, we quantified and characterized microplastics in soils that have been amended with biosolids over the past 23 years. We also collected atmospheric deposition samples to determine the amount and type of plastics added to soils through atmospheric input over a period of about 2 years. Soil samples were taken from a replicated field trial where biosolids have been applied at rates of 0, 4.8, 6.9, and 9.0 t/ha every second crop. The biosolids were anaerobically digested and dewatered, and were applied by spreading onto the soil surface. Soil and atmospheric samples were extracted for microplastics by Fenton's reaction to remove organic matter followed by flotation in a zinc chloride solution to separate plastic from soil particles. Samples were analyzed for microplastics by optical microscopy and Laser Direct Infrared Imaging Analysis (LDIR). The mean number of microplastics identified from biosolids samples was 12,000 particles/kg dry biosolids. The long-term applications of biosolids to the soil led to mean plastics concentrations of 383, 500, and 361 particles/kg dry soil in the 0–10 cm depth for low, medium, and high biosolids application rates, respectively. These plastic concentrations were not significantly different from each other, but significantly higher than those found in non biosolids-amended soil (117 particles/kg dry soil). The dominant plastic types by number found in biosolids were polyurethane, followed by polyethylene, and polyamide. The most abundant plastics in soil samples were polyurethane, polyethylene terephthalate, polyamide, and polyethylene. Atmospheric deposition contributed to 15 particles/kg dry soil per year and was mainly composed of polyamide fibers. This study shows that long-term application of biosolids led to an accumulation of microplastics in soil, but that atmospheric deposition also contributes a considerable input of microplastics.

Water-soluble and Water-dispersible Polymers Used in Commercial Agricultural Formulations: Inventory of Polymers and Perspective on their Environmental Fate.

Agricultural formulations contain water-soluble and water-dispersible polymers (WSPs and WDPs) to increase the application efficiency of the active ingredients (e.g. pesticides and fertilizers). Despite their direct release to soils and crops, there is currently no inventory of used polymers and their fate in soils is poorly studied and understood. Herein, we identify WSPs and WDPs used in agricultural formulations on the German and Swiss markets. By searching the scientific literature, patents, and manufacturer websites, we tentatively identified that 233 of the 1815 listed trade names of formulation additives contained polymers, the majority of which belonged to three main chemical classes: polyethylene glycol (PEG)-based (co)polymers, functionalized polysaccharides (PSacs), and vinylic (co)polymers (VCPs). We report information on their functionalization, molecular weights, and market significance. In 2015, their estimated combined annual application volume in Switzerland surpassed 100 tonnes. Low molecular weight PEGs and natural, unfunctionalized PSacs reportedly biodegrade, suggesting no accumulation in soils associated with their use as formulation additives. Conversely, high molecular weight functionalized PEGs, functionalized PSacs, and the majority of the VCPs have been reported to undergo only slow or no soil biodegradation. These polymers may thus persist and accumulate in agricultural soils, requiring more detailed investigations of their environmental fate and resulting exposure scenarios. There is a need for systematic studies on the effects of polymer structure, molecular weight, and functionalization on soil biodegradability.

Symbiosis with endophyte leads to greater C accumulation in grassland soils

Epichloë coenophiala forms aboveground symbiotic relationships with tall fescue (Festuca arundinacea) and provides the host with better fitness. This study investigated the effects of endophyte symbiosis on carbon mineralization in soil. Two soils were amended with endophyte-infected (E+) or endophyte-free (E−) residues of two tall fescue genotypes. At the end of the experiment, CO2 evolution rates were monitored to quantify the mineralized carbon. The indices of carbon mineralization were significantly greater (LSD, P < 0.05) in the E−compared to E+ plant residue treated soils. Cellulose, hemicellulose, lignin contents, C:N and lignin:N ratios were significantly greater (LSD, P < 0.05) in soils with the E+ residues than in those with E− residues. Additionally, the E+ plant residues consistently contained significantly less N (LSD, P < 0.05). Overall, it is concluded that grass-endophyte symbiosis results in the production of less biodegradable plant residues, in turn reducing the residue biodegradability and promoting greater C accumulation in the soils.

Microplastic removal in managed aquifer recharge using wastewater effluent

Microplastic (MP) pollution has emerged as a pressing environmental issue, with its impacts on ecosystems and human health yet to be fully understood. This study aims to investigate the presence and distribution of MPs in the soil of a managed aquifer recharge (MAR) system, built with different reactive barriers of natural materials and irrigated with the secondary effluent of a wastewater treatment plant (WWTP). MPs were extracted from reactive barrier material following an approach based on the density separation of MPs with posterior oxidant digestion, combined with visual and chemical characterisation by Fourier-Transform Infrared Spectroscopy (FTIR). The results revealed the widespread occurrence of MPs in the MAR soil samples. MPs concentration in the different barrier materials ranged from 60 to 236 n kg−1. The most dominant morphologies were fragments (60%) and fibers (17%), and the most abundant colour was white (51%), followed by transparent MPs (20%). Polypropylene (PP) was detected in all the samples with an abundance of 47%, followed by polyethylene (PE, 34%). The interplay of barrier composition significantly influences the retention of MPs, with compost (T5) and woodchips (T4) exhibiting the most notable retention rates. Remarkably, the outer layers of the reactive barriers display superior retention compared to the deeper layers.The findings of this study demonstrate the good performance of the MAR system in retaining MPs and contribute to the growing body of knowledge on MPs pollution in freshwater systems while providing insights into the dynamics of MPs transport and accumulation in soil. Such information can inform the development of effective wastewater management strategies to mitigate the impacts of these pollutants on water resources and safeguard the environment.

Water and Salinity Variation along the Soil Profile and Groundwater Dynamics of a Fallow Cropland System in the Hetao Irrigation District, China

Managing soil salinity has always been a difficult problem for agriculture. Balancing water and salt while maintaining crop quality and yield is a key issue for agricultural sustainability. The Hetao lrrigation District in China has a complex mix of cultivated and uncultivated land which plays a crucial role in soil salinization processes. To investigate the dynamic properties of soil moisture and salinity, soil ions and groundwater, cultivated and fallow soils in the Hetao lrrigation District were analyzed, side by side, using a combination of field and laboratory tests, with data processed using univariate and multivariate statistical approaches. The results showed that soil moisture increased with increasing soil depth in both cultivated and fallow soils. Salinity showed an increasing trend in 2022 and 2023 from April to September. The soil ions were mainly sulfate in the cultivated soils and chloride in the fallow soils. The characteristic factors affecting salt accumulation in cultivated soils are Na++K+, Cl−, SSC, SO42−, HCO3−, and pH, and the characteristic factors affecting salt accumulation in fallow soils are Na++K+, Cl−, SSC, HCO3−, and pH. Water table depth varied with irrigation and precipitation and was strongly influenced by external environmental factors. Groundwater salinity remained stable throughout the study period. This study provides a theoretical basis for the prevention and control of soil salinization in arid and semiarid areas through the “dry drainage salt” measure.

Effect of Phosphorus Application on Eggplant Cadmium Accumulation and Soil Cadmium Morphology

Soil cadmium (Cd) contamination affects human health, and the application of phosphorus (P) fertilizer can inhibit the toxic effects of Cd; however, the effects of different P fertilizers on Cd accumulation in calcareous soils are unknown. To address this point, this paper used a pot experiment with four P fertilizer types (monoammonium phosphate (MAP), superphosphate (SSP), diammonium phosphate (DAP), and dicalcium phosphate (DCP)) and four P fertilizer levels (0, 0.15, 0.25, and 0.35 g kg−1, P per kg of soil). The effects of P application on the biomass of eggplant, Cd content, bioconcentration factors, translocation factor, yield quality, and soil Cd morphology changes in a Cd-contaminated environment were explored. Applying 0.35 g kg−1 of DCP significantly increased eggplant biomass while reducing Cd accumulation, concentration, and transport within eggplants under Cd contamination. The P fertilizer changed the distribution of soil Cd morphology. A redundancy analysis identified Cd content in the residual and Fe/Mn oxides-bound states as the primary factors influencing Cd levels in plants. In summary, the application of 0.35 g kg−1 DCP proved most efficient in mitigating Cd accumulation in eggplants under Cd-induced stress conditions.

Meta-analysis unveils differential effects of agroforestry on soil properties in different zonobiomes

AimsCurrent comprehensive meta-analysis study aims to explore how agroforestry practices influence soil quality across different climate zones. Since numerous studies proposed agroforestry as the promising agroecological farming systems over conventional monoculture systems to maintain soil quality and to regenerate disturbed soil to counteract the negative consequences of global extensive agricultural approaches.MethodsBy employing the comprehensive meta-analysis technique on data from 125 studies conducted in tropical, temperate, and Mediterranean environments, we quantitatively assessed the effects of agroforestry on physical, chemical, and biological soil quality indicators.ResultsRates of soil erosion, the most important indication of land degradation, were improved in agroforestry systems compared to monocultures, especially in temperate (-138%) and Mediterranean soils (-40%), due to agroforestry-induced improved soil texture, aggregate stability, and soil water regulation. Soil acidification was decreased in tropical (-128%) and Mediterranean soils (-96%), but increased in temperate soils (+ 104%) due to agroforestry practices. Low temperate soil pH suggests high Ca2+ leaching losses as evidenced by decreased Ca2+ (-68%) and increased Fe2+ (+ 129%) and Al3+ (+ 235%) contents. Agroforestry systems increased organic matter accumulation in temperate (+ 86%) and Mediterranean soils (+ 65%), carbon sequestration in all climatic zones (+ 48%: 33–73%), and respiration rates in temperate (+ 119%) and tropical soils (+ 105%). Soil microbial communities, enzyme activities as well as nutrient cycling and availability were generally enhanced in agroforestry systems compared to monocultures.ConclusionsOur results provide compelling evidence that agroforestry practices can contribute substantially to sustainable improvement of global soil quality.

Influence of brassinosteroid and silicon on growth, antioxidant enzymes, and metal uptake of leafy vegetables under wastewater irrigation

Vegetable cultivation under sewage irrigation is a common practice mostly in developing countries due to a lack of freshwater. Long-term usage provokes heavy metals accumulation in soil and ultimately hinders the growth and physiology of crop plants and deteriorates the quality of food. A study was performed to investigate the role of brassinosteroid (BRs) and silicon (Si) on lettuce, spinach, and cabbage under lead (Pb) and cadmium (Cd) contaminated sewage water. The experiment comprises three treatments (control, BRs, and Si) applied under a completely randomized design (CRD) in a growth chamber. BRs and Si application resulted in the highest increase of growth, physiology, and antioxidant enzyme activities when applied under canal water followed by distilled water and sewage water. However, BRs and Si increased the above-determined attributes under the sewage water by reducing the Pb and Cd uptake as compared to the control. It’s concluded that sewerage water adversely affected the growth and development of vegetables by increasing Pb and Cd, and foliar spray of Si and BRs could have great potential to mitigate the adverse effects of heavy metals and improve the growth. The long-term alleviating effect of BRs and Si will be evaluated in the field conditions at different ecological zones.

Bacteria-Virus Interactions Are More Crucial in Soil Organic Carbon Storage than Iron Protection in Biochar-Amended Paddy Soils.

Iron oxides supposedly provide physicochemical protection for soil organic carbon (SOC) under anoxic conditions. Likewise, biochar can modulate the composition of soil microbial communities. However, how Fe oxides and microbial communities influence the fate of SOC with biochar amendment remains unresolved, especially the effect of the bacteria-virus interaction on SOC dynamics. Here, we performed a four-month pot experiment using rice seedlings with a biochar amendment under waterlogged conditions. Then, soil aggregate sizes were examined to explore the factors influencing the SOC patterns and the underlying mechanisms. We found that biochar altered soil enzyme activities, especially in macroaggregates. Fe oxides and necromass exhibited significant negative relationships with SOC. Bacterial communities were notably associated with viral communities. Here, the keystone ecological cluster (module 1) and keystone taxa in the bacteria-virus network showed significant negative correlations with SOC. However, Fe oxides exhibited substantial positive relationships with module 1. In contrast to the prevailing view, the SOC increase was not primarily driven by Fe oxides but strongly influenced by bacteria-virus interactions and keystone taxa. These findings indicate that biochar governs microbial-mediated SOC accumulation in paddy soil and ascertains the role of viruses in regulating the bacterial community, thus predicting SOC stock.

An evaluation on microplastic accumulations in Turkish soils under different land uses

Microplastic (MP) pollution is now widely reported in soil ecosystems. However, the level of this pollution in soil ecosystems has not been sufficiently elucidated. Moreover, there is little understanding of how land use conditions affect the occurrence and distribution of MPs in soils. Therefore, this study examined 55 soil samples (44 agricultural and 11 urban) from the Mediterranean, Aegean, and Marmara regions of Türkiye, representing both agricultural and urban land uses. The samples were analyzed for MP distribution characteristics, such as abundance, shape, size, color, and type. Different types of MPs were detected in the soil samples, and their averages in agricultural and urban soils were 192.7 ± 14.2 and 127.3 ± 21.6 particles kg−1, respectively. MP abundance in the soil exhibited variations between different land uses, with agricultural areas showing higher levels compared to urban areas. In agricultural soils, MPs were predominantly blue-colored (44.6 %), in the form of fibers (74.9 %), smaller than 1000 μm (66.1 %), and primarily constituted polyethylene (90.8 %). In urban areas, MPs were also blue-colored (54.7 %), had a fiber shape (64.2 %), smaller than 1000 μm (70.6 %), and mostly belonged to the polyethylene category (78.5 %). A significant difference in MP concentrations was observed between agricultural and urban areas, reflecting the influence of distinct land uses on MP levels. Moreover, Principal Component Analysis (PCA) revealed that soil properties, including pH, electrical conductivity, organic matter, aggregate stability, average weight diameter, sand, clay, and silt, emerged as the primary determinants influencing the abundance and size of MPs within the soil. These findings contribute valuable insights into the origins of soil MPs and the intricate connections between MPs and varying soil characteristics across diverse land use categories.