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The temperature sensitivity (Q10) of soil organic C (SOC) decomposition is an important parameter to predict C dynamics under climate change. Given that SOC is mainly protected by aggregates and minerals, differentiating the Q10 of the two C fractions helps to explain bulk soil C dynamics. In the present study, we collected agricultural soils from adjacent paddy and upland areas in mid‐temperate (Mollisols) and subtropic (Ultisols) regions of China. We employed density fractionation to separate aggregate‐protected and free mineral‐associated C fractions of soil samples and determined the Q10 of SOC and the two C fractions at 15 and 25°C incubated conditions. Results showed that the Q10 of SOC for Mollisols were lower than that for Ultisols, with an exception of aggregates in upland soils. Aggregate‐protected C had lower Q10 than free mineral‐associated C, except in the upland Mollisols. The Q10 of SOC was negatively correlated with the proportion of C protected in aggregates, whereas it was positively correlated with the proportions of mass or C of free minerals. Given that the mass and C proportion of aggregates in bulk soils of Mollisols were 271% and 80% higher than of Ultisols, respectively, the SOC of Mollisols exhibited lower Q10 than Ultisols. Therefore, stronger soil aggregation and higher proportion of aggregate‐protected C contributed to the lower temperature sensitivity of SOC in Mollisols. Consequently, agricultural practices aimed at promoting soil aggregation will alleviate SOC loss under future global warming scenarios. [ABSTRACT FROM AUTHOR]

Microplastic pollution in agricultural soils has drawn significant attention in recent years. The objective of this study is to investigate the forms and characteristics of microplastic pollution in agricultural soils, specifically focusing on rice and vegetable soil in Xiangtan City. Various analytical techniques including stereomicroscopy, SEM, and FTIR spectroscopy were used to analyze the color, particle size, abundance, and types of microplastics in the study area. The findings indicated that the average abundance of microplastics in the soils in the study area was 4377.44 items/kg, with a maximum of 12,292.33 items/kg. Microplastics with smaller particle sizes were more prevalent, with their colors mainly being yellow, transparent, and black. The shapes of the microplastics were mainly thin-filmy and fibrous, and the types mainly included PE and PP. The abundance of microplastics in the vegetable soil with agricultural films applied was four times more than that without agricultural films. In the research area, the use of agricultural films was the most significant source of microplastics. The study's findings describe the characteristics of microplastic pollution in agricultural soils in Xiangtan City. The findings could serve as a reference for establishing standardized assessments of microplastic pollution in agricultural soils, in addition to offering data support for Xiangtan City's future efforts to safeguard agricultural soils and regulate microplastic pollution. [ABSTRACT FROM AUTHOR]

The aim of the study is to determine the concentration of selected heavy metals in soil contaminated with galvanising fume resulting from a fire in a galvanising plant. Surface horizon of soil exposed to contamination by toxic fumes due to the fire of a galvanising plant in Dębska Wola near Kielce (SE Poland) was analysed. Soil samples were collected in an agricultural area of 12 ha after the plant’s failure in 2019 and three years after the fire in 2022. Grain-size distribution, pH and concentration of zinc, lead and cadmium were determined. The acceptable values of pollutants were significantly exceeded in soil (Znmax – 2007.3 mg∙kg−1 DM, Pbmax – 509.5 mg∙kg−1 DM, Cdmax – 17.1 mg∙kg−1 DM in 0–5 cm horizon) and reduced in control samples (Znmax – 756.1 mg∙kg−1 DM, Pbmax – 320.1 mg∙kg−1 DM, Cdmax – 15 mg∙kg−1 DM). In the organic-mineral horizon the concentrations declined by an average of Zn – 41.8%, Pb – 26.1% and Cd – 16.3%, while in the mineral horizon by 27.8% (Zn), 26.7% (Pb) and 15.6% (Cd). Industrial plants, in which thermal treatment of molten metals is conducted, pose a real threat to the environment in the case of a failure. In order to minimise the effects of potential leaks, their location should be thoroughly considered. The course and consequences of accidents should be monitored during the event (such as fire) and in the long term (e.g. with the use of bioindicators).

The interaction between nanoscale copper oxides (nano-CuOs) and soil matrix significantly affects their fate and transport in soils. This study investigates the retention of nano-CuOs and Cu2+ ions in ten typical agricultural soils by employing the Freundlich adsorption model. Retention of nano-CuOs and Cu2+ in soils was well fitted by the Freundlich model. The retention parameters (KD, KF, and N) followed an order of CuO NTs > CuO NPs > Cu2+, highlighting significant impact of nano-CuOs morphology. The KF and N values of CuO NPs/Cu2+ were positively correlated with soil pH and electrical conductivity (EC), but exhibited a weaker correlation for CuO NTs. Soil pH and/or EC could be used to predict KF and N values of CuO NPs or CuO NTs, with additional clay content should be included for Cu2+.The different relationship between retention parameters and soil properties may suggest that CuO NTs retention mainly caused by agglomeration, whereas adsorption and agglomeration were of equal importance to CuO NPs. The amendment of Ca2+ at low and medium concentration promoted retention of nano-CuOs in alkaline soils, but reduced at high concentration. These findings provided critical insights into the fate of nano-CuOs in soil environments, with significant implications for environmental risk assessment and soil remediation strategies. [ABSTRACT FROM AUTHOR]

Soil organic matter (SOM) and the ratio of soil organic carbon to total nitrogen (C/N ratio) are fundamental to the ecosystem services provided by soils. Therefore, understanding the spatial distribution and relationships between the SOM components mineral-associated organic matter (MAOM), particulate organic matter (POM), and C/N ratio is crucial. Three ensemble machine learning models were trained to obtain spatial predictions of the C/N ratio, MAOM, and POM in German agricultural topsoil (0–10 cm). Parameter optimization and model evaluation were performed using nested cross-validation. Additionally, a modification to the regressor chain was applied to capture and interpret the interactions among the C/N ratio, MAOM, and POM. The ensemble models yielded mean absolute percent errors (MAPEs) of 8.2% for the C/N ratio, 14.8% for MAOM, and 28.6% for POM. Soil type, pedo-climatic region, hydrological unit, and soilscapes were found to explain 75% of the variance in MAOM and POM, and 50% in the C/N ratio. The modified regressor chain indicated a nonlinear relationship between the C/N ratio and SOM due to the different decomposition rates of SOM as a result of variety in its nutrient quality. These spatial predictions enhance the understanding of soil properties' distribution in Germany. [ABSTRACT FROM AUTHOR]

The dissemination of antibiotic resistance genes (ARGs) in soil has become a global environmental issue. Vermicomposting is gaining prominence in agricultural practices as a soil amendment to improve soil quality. However, its impact on soil ARGs remains unclear when it occurs in farmland. We comprehensively explored the evolution and fate of ARGs and their hosts in the field soil profiles under vermicompost application for more than 3 years. Vermicompost application increased several ARG loads in soil environment but decreased the high-risk bla -ARGs (bla ampC , bla NDM , and bla GES-1) by log(0.04 – 0.43). ARGs in soil amended with vermicompost primarily occurred in topsoil (approximately 1.04-fold of unfertilized soil), but it is worth noting that their levels in the 40–60 cm soil layer were the same or even less than in the unfertilized soil. The microbial community structure changed in soil profiles after vermicompost application. Vermicompost application altered the microbial community structure in soil profiles, showing that the dominant bacteria (i.e., Proteobacteria, Actinobacteriota, Firmicutes) were decreased 2.62%–5.48% with the increase of soil depth. A network analysis further revealed that most of ARG dominant host bacteria did not migrate from surface soil to deep soil. In particular, those host bacteria harboring high-risk bla -ARGs were primarily concentrated in the surface soil. This study highlights a lower risk of the propagation of ARGs caused by vermicompost application and provides a novel approach to reduce and relieve the dissemination of ARGs derived from animals in agricultural production. [Display omitted] [ABSTRACT FROM AUTHOR]

The aim of the study is to determine the concentration of selected heavy metals in soil contaminated with galvanising fume resulting from a fire in a galvanising plant. Surface horizon of soil exposed to contamination by toxic fumes due to the fire of a galvanising plant in Dębska Wola near Kielce (SE Poland) was analysed. Soil samples were collected in an agricultural area of 12 ha after the plant's failure in 2019 and three years after the fire in 2022. Grain-size distribution, pH and concentration of zinc, lead and cadmium were determined. The acceptable values of pollutants were significantly exceeded in soil (Znmax - 2007.3 mg·kg-1 DM, Pbmax - 509.5 mg·kg-1 DM, Cdmax - 17.1 mg·kg-1 DM in 0-5 cm horizon) and reduced in control samples (Znmax - 756.1 mg·kg-1 DM, Pbmax - 320.1 mg·kg-1 DM, Cdmax - 15 mg·kg-1 DM). In the organic-mineral horizon the concentrations declined by an average of Zn - 41.8%, Pb - 26.1% and Cd - 16.3%, while in the mineral horizon by 27.8% (Zn), 26.7% (Pb) and 15.6% (Cd). Industrial plants, in which thermal treatment of molten metals is conducted, pose a real threat to the environment in the case of a failure. In order to minimise the effects of potential leaks, their location should be thoroughly considered. The course and consequences of accidents should be monitored during the event (such as fire) and in the long term (e.g. with the use of bioindicators). [ABSTRACT FROM AUTHOR]

Purpose: The pollution caused by heavy metals including As, Cd, Hg and Pb in the agricultural soils around the Yangshan gold deposit has been investigated, and the Anba ore section was taken as an example in this paper. Method: We have collected 80 topsoil and 15 vertical soil samples, combined using multiple methods to make the pollution assessment. Based on correlation analyses and previous geochemical results, the heavy metals sources and their vertical variations have been determined. Result: The average of As, Cd, Hg, and Pb concentrations is larger than that in the Longnan city. The As distributions are mainly influenced by human activities and belong to low-degree pollution. The As shows moderate accumulation. The Hg and Pb also display a certain degree of enrichment. The potential ecological hazard grade in the study area is medium. Conclusion: The shallow surface contains highly heavy metals, and their pollution may have diffused to the deeper depth. The As, Hg, and Pb were mainly derived from illegal gold mining and Pingdong construction, which were also influenced by transportation, whereas the Cd was mainly came from the soil materials. Significance: That can provide the basis for later mine construction and development. [ABSTRACT FROM AUTHOR]

Up to 70% of the nitrogen (N) fertilizer applied to agricultural soils is lost through microbially mediated processes, such as nitrification. This can be counteracted by synthetic and biological compounds that inhibit nitrification. However, for many biological nitrification inhibitors (BNIs), the interaction with soil properties, nitrifier specificity, and effective concentrations are unclear. Here, we investigated three synthetic nitrification inhibitors (SNIs) (DCD, DMPP, and nitrapyrin) and three BNIs [methyl 3(4-hydroxyphenyl) propionate (MHPP), methyl 3(4-hydroxyphenyl) acrylate (MHPA), and limonene] in two agricultural soils differing in pH and nitrifier communities. The efficacies of SNIs and BNIs were resilient to short-term pH changes in the neutral pH soil, whereas the efficacy of some BNIs increased by neutralizing the alkaline soil. Among the BNIs, MHPA showed the highest inhibition and was, together with MHPP, identified as a putative AOB/comammox-selective inhibitor. Additionally, MHPA and limonene effectively inhibited nitrification at concentrations comparable to those used for DCD. Moreover, we identified the effective concentrations at which 50% and 80% of inhibition is observed (EC50 and EC80) for the BNIs, and similar EC80 values were observed in both soils. Overall, our results show that these BNIs could potentially serve as effective alternatives to SNIs currently used. [ABSTRACT FROM AUTHOR]

The presence of heavy metals in soil has gained considerable attention due to their potential risks to ecosystems and human health. In this study, a thorough soil investigation was performed in the hilly region of central Hainan, which was formerly regarded as an area with the highest ecological environmental quality. A total of 7094 soil samples were systematically collected with high density over a large area. Simultaneously, a detailed investigation was conducted on the surrounding environment of each sampling point, including environmental factors such as soil, land use and crop types. The soil samples were analysed for heavy metals, pH, organic matter, and other parameters. The soil heavy metal pollution level, ecological risk and health risk were evaluated using the geo-accumulation index and the potential ecological risk index. The findings showed that the average contents of the heavy metals As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in the soil were 1.68, 0.042, 24.2, 6.49, 0.0319, 7.06, 29.6 and 49.8 mg·kg−1 respectively. Except for Hg, the mean values of the other heavy metals were either lower than or similar to the background values of Hainan. Also, only a few localised areas showed contamination by heavy metals. The primary sources of heavy metals, identified by a positive matrix factorisation model, could be categorised into four types: natural sources related to the soil formation process from acidic intrusive rocks (such as granite); natural sources primarily influenced by atmospheric deposition; anthropogenic sources associated with agricultural activities; and natural sources related to the soil formation process from middle-mafic intrusive rocks and black shales. The correlation analysis and variance analysis findings suggested that the content of heavy metals in the soil was primarily associated with the parent rock. The study area generally had low heavy metal levels and was not significantly polluted. However, agricultural activities still affected the enrichment of heavy metals. Therefore, it is imperative to remain vigilant about the ecological risks linked to soil heavy metals while continuing land development and expanding agricultural activities in the future. These findings indicate that conducting high-density soil surveys can enhance our understanding of regional soil heavy metals and enable reliable recommendations for agricultural planning. Whether in areas with low pollution risk or potential pollution risk, it is recommended that high-density soil surveys be conducted provide scientific guidance for further agricultural development. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Agricultural soils are substantial receptors of plastic pollution. Plastic crop covers, a facet of agriplastics, may represent an important contribution to microplastic load in agricultural soils. The authors present a nationwide study of agricultural soils in the United Kingdom, comparing microplastic load between sites where plastic crop covers are and are not used for carrot and potato production. Sites where plastic crop covers were used received a higher microplastic load compared with sites where no plastic crop cover was used. The effects of microplastic pollution are largely unknown, requiring further research to determine the impact on soil, crop and human health. Summary Agricultural soils are substantial receptors of plastic pollution, with agriplastics potentially making an important contribution to the overall microplastic load to agricultural soils. The intensive use and mismanagement of plastic crop covers, particularly plastic mulch films, nets and fleeces, represent a pollution pathway. In this study, we have analysed the microplastic concentrations in agricultural soils in 324 samples from 108 sites across the United Kingdom, where carrots or potatoes were grown, using a combined digestion and density separation method. Microplastics were stained with Nile Red and quantified using fluorescence microscopy. Microplastic concentrations ranged from 1320 to 8190 particles kg−1, with a mean of 3680 ± 129.1 particles kg−1. Where no plastic crop covers were used for potato and carrot production, a mean of 2667 ± 84.1 particles kg−1 were detected. At sites where plastic crop covers were used in the past 10 years, a mean of 4689 ± 147.1 particles kg−1 were recorded. There was a significant difference in microplastic abundance between sites where plastic crop covers were and were not used (p ≤ 0.001), confirming that plastic crop covers are an important source of microplastics to agricultural soils. Further studies are needed to investigate microplastic occurrence in the environment to better understand their impact on soil, crops and human health.

Soil organic carbon (SOC) is used for soil health, indicating soils’ agricultural productivity potential, and correlating with other functions like water capacity and soil biodiversity. SOC stocks are increasingly recognized in climate change mitigation strategies. Soil carbon sequestration represents 25% of all natural climate solutions to carbon. Current SOC maps for Great Britain (GB) are limited due to their coarse resolution (0.5–1 km). High demand exists for fine resolution SOC maps to estimate stock baselines and inform field-scale sampling strategies and land management. We present SOC concentration and stock maps at 5 m resolution for GB, generated using machine learning and accounting for physical and chemical soil properties, weather, topography and land cover (LC). Our model explains 74% of SOC variability in the evaluation dataset, with a RMSE of 9.8 (tC ha− 1). Soil pH and LC are the most important SOC predictors. We estimate ~ 2704Tg SOC for GB in the soil’s top 30 cm: 1403Tg in England, 283Tg in Wales, and 1017Tg in Scotland. Neutral grasslands contribute the most SOC in England and Wales (37.2% and 50.7%). Dwarf heath shrubs, bogs and natural grasslands have higher contributions in Scotland (22–25%). Our SOC stock estimation compares with previous studies and our map reflects expected SOC distribution for different parts of GB under different LCs. Its high spatial resolution and accuracy enable SOC assessment at small scales (a single farm or a field) and can help to develop sustainable land management and guide soil sampling by optimizing sampling size and cost.

Soils are a hotspot for the emergence and spread of antibiotic resistance. The effects of agrochemical treatments on the bacterial community of agricultural soils and the content of antibiotic-resistance genes (ARGs) were studied. Treatments included the following: control, mineral fertilizers (NPKs), pesticides, and the combined treatment of soils under soya (Glycine max), sunflower (Helianthus annuus L.), and wheat (Triticum aestivum). Bacterial community taxonomic composition was studied using 16S rRNA gene sequencing. The content of 10 ARGs and 3 integron genes (intI1, intI2, intI3) was determined using quantitative real-time PCR. The results showed that the treatments had little effect on the taxonomic composition and diversity of the soil bacterial community. The most significant factors determining differences in the microbial community were sampling time and soil physico-chemical parameters. A significant role of the bacterial community in ARG distribution in soils was demonstrated. Representatives of the Pseudomonas, Bacillus, Sphingomonas, Arthrobacter genera, and the Nocardioidaceae and Micrococcaceae families were likely ARG hosts. The presence of integron genes of all three classes was detected, the most numerous being intI3. This work provides important information on the role of agricultural soils in ARG transfer, and the findings may be useful for sustainable and safe agricultural development. [ABSTRACT FROM AUTHOR]

The widespread use of rare earth elements (REEs) across various industries makes them a new type of pollutant. Additionally, REEs are powerful indicators of geochemical processes. As one of the two main rivers in the Aral Sea, identifying the geochemical behavior of REEs in agricultural soils of the Syr Darya River is of great significance for subsequent indicative studies. In this study, the geochemical characteristics, influencing factors, and potential application significance of REEs in agricultural soils from three sampling areas along the Syr Darya River were analyzed using soil geography and elemental geochemical analyses. The results showed that the highest total concentration of REEs in the agricultural soil was in Area I, with a mean value of 142.49 μg/g, followed by Area III with a mean value of 124.56 μg/g, and the lowest concentration was in Area II with a mean value of 122.48 μg/g. The agricultural soils in the three regions were enriched in light rare earth elements (LREEs), with mean L/H values of 10.54, 10.13, and 10.24, respectively. The differentiation between light and heavy rare earth elements (HREEs) was also high. The concentration of REEs in agricultural soil along the Syr Darya River was primarily influenced by minerals such as monazite and zircon, rather than human activities (the pollution index of all REEs was less than 1.5). The relationship between Sm and Gd can differentiate soils impacted by agricultural activities from natural background soils. The results of this study can serve as a basis for indicative studies of REEs in Central Asia. [ABSTRACT FROM AUTHOR]

Pesticides and fertilizers used in agriculture can negatively affect the soil, increasing its toxicity. In this work, a battery of whole-cell bacterial lux-biosensors based on the E. coli MG1655 strain with various inducible promoters, as well as the natural luminous Vibrio aquamarinus VKPM B-11245 strain, were used to assess the effects of agrochemical soil treatments. The advantages of using biosensors are sensitivity, specificity, low cost of analysis, and the ability to assess the total effect of toxicants on a living cell and the type of their toxic effect. Using the V. aquamarinus VKPM B-11245 strain, the synergistic effect of combined soil treatment with pesticides and mineral fertilizers was shown, which led to an increase in the overall (integral) toxicity of soils higher than that of the individual application of substances. Several probable implementation mechanisms of agrochemical toxic effects have been discovered. DNA damage caused by both SOS response induction and alkylation, oxidative stress due to increased superoxide levels, and damage to cellular proteins and membranes are among them. Thus, the usage of biosensors makes it possible to assess the cumulative effect of various toxicants on living organisms without using expensive chemical analyses. [ABSTRACT FROM AUTHOR]

Copyright of Asian Journals of Ecotoxicology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Agriculture is the main economic activity of Mozambique and there is a lack of information about the quality of agricultural soils. In this paper, five soils from the Manica and Sussundenga districts (Manica province) sampled in the years 2021/2022 and 2022/2023 (before and after the rainy seasons) were subjected to an agronomical and environmental chemical analysis to assess their quality, from the fertility and environmental contamination points of view. Standard analytical methodologies from external certified laboratories and local X-ray fluorescence measurements were used. All the studied soils were acidic (pH ranging from 4.5 to 5.4), had no salinity problems (conductivity ranging from 4.2 to 11.8 mS/m), and had a low amount of soil organic matter (0.90% to 1.81%). Soils from the Sussundenga district had a very low cation exchange capacity (CEC) (average of 3.33 cmolc/kg), while that of those from the Manica district ranged from very low to average CEC (3.59 to 13.11 cmolc/kg). Sussundenga soils also had a phosphorous deficiency (values ranging from <20 to 38.5 mg/kg) and there were deficiencies and/or excesses of some macro and micronutrients in all soil samples. Manica soils were contaminated, apparently from geogenic origin, with Cr (280 to 1400 mg/kg), Co (80 mg/kg), Ni (78 to 680 mg/kg) and V (86 mg/kg). Agricultural soil monitoring must be fostered in Mozambique in order to improve food quality and quantity to ensure economic and environmental sustainability. [ABSTRACT FROM AUTHOR]

Dichlorodiphenyltrichloroethane (DDT) is well known for its harmful effects and has been officially banned as a pesticide around the world. However, DDT pollution still exists in natural environments in China because DDT degrade very slowly. In this study, 60 soil samples were collected from Cixi, Zhejiang Province, and the levels of DDTs and its metabolites in soil and health risks were investigated. The results showed that the detection rate of DDT in soil samples were 100%, and the total DDTs residue in soil ranged from 0.007 to 1.208 mg/kg, with an average of 0. 113±0. 035 mg/kg, which exceeded the second-level Chinese soil environmental quality standard for farmland soil. The average residuals of p,p'-DDT, p,p'-DDE (dichlorodiphenyldichloroethylene), p,p'-DDD (dichlorodiphenyldichloroethane) and o,p'-DDT accounted for 34.8%, 50.9%, 8.0% and 6.3% of the total DDTs, respectively. The DDD/DDE ratios indicated a dehydrochlorination of DDT to DDE under aerobic conditions at most sampling sites. The ratios of (p,p'-DDE+p,p'-DDD)/p,p'-DDT and o,p'-DDT/p,p'-DDT indicating the DDT in the field were mainly introduced via industrial DDT and dicofol, including historical residue and fresh input. The health risk assessment showed that DDT-contaminated sites do not pose a non-carcinogenic risk to humans, and pose a very low risk of cancer to children and a low risk of cancer to adults. Overall, this study helps to understand the distribution, sources and health risks of DDT in typical soils. [ABSTRACT FROM AUTHOR]

The European Union's soil strategy for 2030 has set the objective of achieving 'healthy soils' in Europe by 2050. To achieve this ambitious goal, dedicated soil science skills will be needed in the future. This article presents the results of a survey on soil science skills for the future conducted within the framework of the European Joint Program—EJP SOIL. The survey was distributed online in the 24 countries participating in the EJP SOIL. The skills were expressed as having knowledge in particular topics related to soils, practical know‐hows or abilities or outcomes of knowledge and know‐hows put into action. No significant differences in the importance of soil‐science related skills were found between countries or stakeholder categories. The two groups of skills that ranked at the top of stakeholders' concern were 'Having a scientific basis of knowledge on soils and their functioning' and 'Knowing how to mobilise agronomic drivers to manage and protect soils'. This means that there is a need for people with an in‐depth knowledge in soil science, but also soil scientists with integrated knowledge in agronomy and crop production. Three important findings relate to the knowledge of soil science itself: (i) there is a clear need to develop the knowledge of the biological and ecological functioning of soil; (ii) this should not happen at the expense of a strong general knowledge of the fundamentals of soil science; (iii) future soil scientists should be trained to have a more holistic appreciation of soil rather than be trained as a specialist of a specific aspect of soil science only. Being able to exchange knowledge with farmers, knowing how to assess soil fertility, quality or health and how to improve them are viewed as essential skills for the future. These findings offer a clear path for the evolution of soil science education curricula across Europe. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Agricultural soils are substantial receptors of plastic pollution. Plastic crop covers, a facet of agriplastics, may represent an important contribution to microplastic load in agricultural soils. The authors present a nationwide study of agricultural soils in the United Kingdom, comparing microplastic load between sites where plastic crop covers are and are not used for carrot and potato production. Sites where plastic crop covers were used received a higher microplastic load compared with sites where no plastic crop cover was used. The effects of microplastic pollution are largely unknown, requiring further research to determine the impact on soil, crop and human health. Summary: Agricultural soils are substantial receptors of plastic pollution, with agriplastics potentially making an important contribution to the overall microplastic load to agricultural soils. The intensive use and mismanagement of plastic crop covers, particularly plastic mulch films, nets and fleeces, represent a pollution pathway.In this study, we have analysed the microplastic concentrations in agricultural soils in 324 samples from 108 sites across the United Kingdom, where carrots or potatoes were grown, using a combined digestion and density separation method. Microplastics were stained with Nile Red and quantified using fluorescence microscopy.Microplastic concentrations ranged from 1320 to 8190 particles kg−1, with a mean of 3680 ± 129.1 particles kg−1. Where no plastic crop covers were used for potato and carrot production, a mean of 2667 ± 84.1 particles kg−1 were detected. At sites where plastic crop covers were used in the past 10 years, a mean of 4689 ± 147.1 particles kg−1 were recorded.There was a significant difference in microplastic abundance between sites where plastic crop covers were and were not used (p ≤ 0.001), confirming that plastic crop covers are an important source of microplastics to agricultural soils. Further studies are needed to investigate microplastic occurrence in the environment to better understand their impact on soil, crops and human health. [ABSTRACT FROM AUTHOR]

Over the past few decades, the issue of heavy metal contamination in agricultural soils has gained significant attention due to its potential threat to soil ecosystems, food security, and human health. This research studied the source and potential risk associated with heavy metals in agricultural soils of Mian-Ab plain, Khuzestan, Iran. Source identification of the heavy metals using different methods indicated a combination of natural and anthropogenic (agricultural activities and vehicle emissions) origin. According to the positive matrix fraction (PMF) model, natural sources were found to be dominant for elements such as As (69%), V (58%), Mn (55%), Co (54%), Cr (50%), and Ni (48%). In contrast, atmospheric deposition, mainly from vehicle emission was a major contributor to Pb (72%), Cu (30%), and Zn (30%), while, agricultural activities, particularly fertilizer use, were associated with Zn (29%), Cd (29%), Cr (28%), and Cu (26%). The quality assessment of the agricultural soil in the study area showed low to moderate contamination of Cd, Cu, Pb, and Zn in some stations. Human health risk assessment indicated that non-carcinogenic and carcinogenic risks for adults through different pathways were negligible. However, the total carcinogenic risk for children (6.8 × 10-6) exceeded the safety level (1×10-6), indicating a potential risk of developing cancer. Notably, heavy metals such as As and Ni were identified as the primary contributors to this carcinogenic risk. [ABSTRACT FROM AUTHOR]

The pollution of heavy metals (HMs) in agricultural soils profoundly threatens national food safety, and the mobility and environmental behaviors of HMs are closely implicated in crop safety. Here, we assessed the pollution level and mobility of ten HMs and explored their environmental behaviors in the soils of three different land uses from a main crop production zone in eastern China. The concentrations of HMs in the soils were higher in the farmland than the woodland and wasteland, and Cd showed a relatively higher pollution and ecological risk levels compared to other metals. Cadmium was dominated by the reducible (41%) and exchangeable (23%) fractions, and the rest of HMs were mainly in the residual fraction (> 60%). The significant correlation between the exchangeable and DGT-labile Cd indicates relatively higher mobility of Cd in the soils. Soil pH, organic matters and mineral elements had significant correlation with the exchangeable and reducible fractions of most of the HMs (e.g., Cd, Co, Mn, Ni, Pb and V; p < 0.05), indicating their good predictors of the HMs mobility. However, this was not the case for the DGT-labile fraction, which suggests a marked difference in the controlling mechanisms of the mobility versus potential bioavailability of HMs in the soils. The results of this study indicate that both the chemically extracted fractions and the bioavailable fractions of HMs need be considered when effectively assessing the safety of agricultural soils. [ABSTRACT FROM AUTHOR]

Source apportionment and risk assessment are critical for making effective pollution prevention and control policies. The study was carried out to assess source-specific ecological and human health risks associated with heavy metals in farmland soils in Yingtan City based on apportionment results of receptor models. Multivariate analysis and the APCS-MLR model consistently revealed that As, Ni, and Cr in agricultural soils may be mainly derived from natural sources, while the contents of Cu, Zn, Cd, and Pb have been significantly elevated by human activities. According to the outputs of the APCS-MLR model, Cu (34.3%), Zn (67.2%), Pb (75.1%), and Cd (67.9%) primarily originated from the industrial activities related to mineral mining and non-ferrous metal smelting processes. The source-specific ecological risk assessment indicated that industrial sources were the primary contributor to the total ecological risks, posing moderate to high risks in the southern mountainous regions. Natural origins played a significant role in the health risks due to the substantial amounts of As naturally occurring in the soils. The findings could guide the development of effective risk management and pollution control measures for agricultural soils. [ABSTRACT FROM AUTHOR]

Soil erosion poses a significant threat to agricultural production worldwide, with a still-debated impact on the current increase in atmospheric CO2. Whether erosion acts as a net carbon (C) source or sink also depends on how it influences greenhouse gas (GHG) emissions via its impact on crop yield and nutrient loss. These effects on the environmental impacts of crops remain to be considered. To fill this gap, we combined watershed-scale erosion modeling with life cycle assessment to evaluate the influence of soil erosion on environmental impacts of wheat production in the Ebro River basin in Spain. This study is the very first to address the full GHG balance of erosion including its impact on soil fertility and its feedback on crop yields. Two scenarios were simulated from 1860 to 2005: an eroded basin involving conventional agricultural practices, and a non-eroded basin involving conservation practices such as no-till. Life cycle assessment followed a cradle-to-farm-gate approach with a focus on recent decades (1985–2005). The mean simulated soil erosion of the eroded basin was 2.6 t ha−1 year−1 compared to the non-eroded basin. Simulated soils in both eroded and non-eroded basins lost organic C over time, with the former emitting an additional 55 kg CO2 ha−1 year−1. This net C source represented only 3% of the overall life cycle GHG emissions of wheat grain, while the emissions related to the increase of fertilizer inputs to compensate for N and P losses contributed a similar percentage. Wheat yield was the most influential parameter, being up to 61% higher when implementing conservation practices. Even at the basin scale, erosion did not emerge as a net C sink and increased GHG emissions of wheat by 7–70%. Nonetheless, controlling erosion through soil conservation practices is strongly recommended to preserve soils, increase crop yields, and mitigate GHG emissions. [ABSTRACT FROM AUTHOR]

This work evaluated the biochemical responses of the endogeic earthworm Balanteodrilus extremus exposed for 14 and 48 days (d) to soils collected from two tropical agricultural systems: maize-sorghum (MS) and soybean-sorghum (SS). A soil without agricultural management (WAM) and the use of pesticides was selected as a reference. The presence of organochlorine (OC) and organophosphate (OP) pesticide residues was quantified in MS and SS soils. Biomarkers of detoxification [glutathione S transferase (GST)], neurotoxicity [acetylcholinesterase (AChE)] and oxidative stress [superoxide dismutase (SOD), catalase (CAT) and lipoperoxidation (LPO)] were evaluated in B. extremus. The concentration of OP pesticide residues was higher in SS than in MS. Activity of AChE in B. extremus exposed to SS soil for 14 d was significantly more inhibited (78%) than in MS soil (68%). B. extremus has been shown to be a good bioindicator of contaminated soils in tropical regions. [ABSTRACT FROM AUTHOR]

Land use has a great impact on soil dynamics. The soils of various land use systems in Central Karakoram have been under immense pressure in the recent past due to certain anthropogenic activities such as land use practices and land use cover changes. These influences have an impact on the spatial distribution of metallic elements (MEs) in the soils of various land uses. Herein, we investigated the occurrence of the MEs, copper (Cu), zinc (Zn), and nickel (Ni), in soils of various land uses such as the permafrost, pasture, forest, and agricultural lands of the Central Karakorum region. The MEs were extracted in exchangeable, adsorbed, organically bound, carbonated, precipitated, and residual forms. The concentrations of MEs showed a significant dependence on the extraction method used, and the extraction trend followed the order of EDTA > HNO3 > KNO3 > NaOH > H2O. Zn showed the highest concentration compared to Ni and Cu in all extractions, whereas the land uses' ME concentration followed the order of agricultural land > permafrost > forest > pasturelands. The highest values of total Zn, Ni, and Cu were 712 ± 01 mg/kg, 656 ± 02 mg/kg, and 163 ± 02 mg/kg, respectively, in agricultural soil. The ME concentration showed significant variations between different land uses, and the highest concentration was noted in agricultural soil. Zn was found to be a dominant ME compared to Ni and Cu. We believe this effort will provide opportunities for scholars to investigate MEs around the globe. [ABSTRACT FROM AUTHOR]

Soil pollution by heavy metals can cause continuing damage to ecosystems and the human body. In this study, we collected nine fresh topsoil samples and 18 maize samples (including nine leaf samples and nine corn samples) from agricultural soils in the Baiyin mining areas. The results showed that the order of heavy metal concentrations (mg/kg) in agricultural soils was as follows: Zn (377.40) > Pb (125.06) > Cu (75.06) > Ni (28.29) > Cd (5.46) > Hg (0.37). Cd, Cu, Zn, and Pb exceeded the Chinese risk limit for agricultural soil pollution. The average the pollution load index (4.39) was greater than 3, indicating a heavy contamination level. The element that contributed the most to contamination and high ecological risk in soil was Cd. Principal component analysis (PCA) and Pearson's correlation analysis indicated that the sources of Ni, Cd, Cu, and Zn in the soil were primarily mixed, involving both industrial and agricultural activities, whereas the sources of Hg and Pb included both industrial and transportation activities. Adults and children are not likely to experience non-carcinogenic impacts from the soil in this region. Nonetheless, it was important to be aware of the elevated cancer risk presented by Cd, Pb, and especially Ni. The exceedance rates of Cd and Pb in corn were 66.67% and 33.3%, respectively. The results of this research provide data to improve soil protection, human health monitoring, and crop management in the Baiyin district. [ABSTRACT FROM AUTHOR]

Soil fertility, soil health and environmental management through the estimation of background concentration of potentially toxic elements is required for environmental safety. This study aims at investigating the concentration, fertility and potential health risks of some d-block metals (Ti, V, Fe, Mn, and Mo) in some agricultural soils, and establishes the relationship between the metals and some soil properties. Eight elevation ranges resulted from the digital elevation models of the study area; two in Ishibori (NG1, NG2), three each in Agoi-Ibami (CG1, CG2, CG3) and Mfamosing (SG1, SG2 and SG3). One soil profile pit was sunk along each of the elevations. Thirty-five composite soil samples were collected at 0–30, 30–60, 60–90, 90–120, 120–150, 150–180 and 180–200 cm depending on soil depth. Only the profile means of Mn (660.82 ± 612.89 mg/kg) and Mo (2.61 ± 0.73 mg/kg) exceeded permissible concentrations and would pose threats to the environment. Also, the concentrations of the d-block metals exceeded permissible values in Ishibori making them prone to toxicity. The metals were irregularly distributed with depth; however, Mn and Fe were concentrated in the subsurface soils. Clay and sand contents correlated positively and negatively, respectively with all the d-block metals at p < 0.05. The linear model was more efficient in estimating V and Mo via soil properties with adjusted R2 of 33 – 67% for the metals. In conclusion, agricultural activities and geology may influence the accumulation of d-block metals, hence the call for environmental monitoring to curtail metals' assimilation by crops. Highlights: • Mn and Mo threaten the environment the most. • Soils in the Southern Guinea Savannah are most prone to d-block metals contamination. • BD, pH, Mg, and CEC are the best predictors of d-block metals in the soils. • The linear model was best performing in the estimation of V and Mo, respectively. [ABSTRACT FROM AUTHOR]

Heilongjiang Province, the largest commercial grain base in China, experiences significant challenges due to the environmental effects on its soil. The freezing and thawing cycle in this region leads to the transport of water and heat, as well as the exchange and transfer of energy. Consequently, this exacerbates the flooding disaster in spring and severely hampers farming activities such as plowing and sowing. To gain a better understanding of the freezing and thawing mechanisms of farmland soil in cold regions and prevent spring flooding disasters, this study focuses on Heilongjiang Province as a representative area in northeast China. The research specifically investigates the frozen and thawed soil of farmland, using a large-scale low-temperature laboratory to simulate both artificial and natural climate conditions in the cold zone. By employing the similarity principle of geotechnical model testing, the study aims to efficiently simulate the engineering prototypes and replicate the process of large-span and long-time low temperatures. The investigation primarily focuses on the evolution laws of key parameters, such as the temperature field and moisture field of farmland soil during the freeze–thaw cycle. The findings demonstrate that the cooling process of soil can be categorized into three stages: rapid cooling, slow cooling, and freezing stabilization. As the soil depth increases, the variability of the soil temperature gradually diminishes. During the melting stage, the soil's water content exhibits a gradual increase as the temperature rises. The range of water content variation during thawing at depths of 30 cm, 40 cm, 50 cm, and 80 cm is 0.12% to 0.52%, 0.47% to 1.08%, 0.46% to 1.96%, and 0.8% to 3.23%, respectively. To analyze the hydrothermal coupling process of farmland soil during the freeze–thaw cycle, a theoretical model of hydrothermal coupling was developed based on principles of mass conservation, energy conservation, Darcy's law of unsaturated soil water flow, and heat conduction theory. Mathematical transformations were applied after defining the relative degree of saturation and solid–liquid ratio as field functions with respect to the relative degree of saturation and temperature. The simulated temperature and moisture fields align well with the measured data, indicating that the water–heat coupling model established in this study holds significant theoretical and practical value for accurately predicting soil temperature and moisture content during the spring sowing period, as well as for efficiently and effectively utilizing frozen soil resources in cold regions. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the pollution characteristics, source apportionment, and health risks associated with trace metal(loid)s (TMs) in the major agricultural producing areas in Chongqing, China. We analyzed the source apportionment and assessed the health risk of TMs in agricultural soils by using positive matrix factorization (PMF) model and health risk assessment (HRA) model based on Monte Carlo simulation. Meanwhile, we combined PMF and HRA models to explore the health risks of TMs in agricultural soils by different pollution sources to determine the priority control factors. Results showed that the average contents of cadmium (Cd), arsenic (As), lead (Pb), chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn) in the soil were found to be 0.26, 5.93, 27.14, 61.32, 23.81, 32.45, and 78.65 mg/kg, respectively. Spatial analysis and source apportionment analysis revealed that urban and industrial sources, agricultural sources, and natural sources accounted for 33.0%, 27.7%, and 39.3% of TM accumulation in the soil, respectively. In the HRA model based on Monte Carlo simulation, non-carcinogenic risks were deemed negligible (hazard index <1), the carcinogenic risks were at acceptable level (10−6 −4), with higher risks observed for children compared to adults. The relationship between TMs, their sources, and health risks indicated that urban and industrial sources were primarily associated with As, contributing to 75.1% of carcinogenic risks and 55.7% of non-carcinogenic risks, making them the primary control factors. Meanwhile, agricultural sources were primarily linked to Cd and Pb, contributing to 13.1% of carcinogenic risks and 21.8% of non-carcinogenic risks, designating them as secondary control factors. [ABSTRACT FROM AUTHOR]

Phthalates are ubiquitous contaminants occurring in all environmental compartments worldwide. In soils, it occurs at higher levels compared to other organic contaminants. Consequently, humans are exposed to phthalates constantly via air, dust, food and water. This paper reviews phthalates occurrence in soils of agricultural, industrial and urban areas. Diethyl hexyl phthalate and di-n-butyl phthalate are frequently detected in these areas, and their combined concentrations contribute about 60–80% to total phthalate concentrations. Microbial degradation is the primary process determining the fate of phthalates in soil. Gas, and liquid chromatographic techniques coupled to mass spectrometry techniques are generally used for phthalates determination. Reliable quantitation warrants stringent quality control measures as phthalates are present in laboratory air, solvents, and other labwares. Suggestions to minimise background contamination are outlined. [ABSTRACT FROM AUTHOR]

This investigation examines the transport of metal- and pesticide-polluted dust emitted by one of the most relevant agricultural areas of Northwestern Mexico. In the contaminated area, an excessive water extraction of the aquifer and seawater intrusion caused the abandonment of fields, which are pollutant-loaded dust emitters. We used air mass forward trajectories (HYSPLIT) model to obtain particle trajectories in the wind and the use of banned pesticides as geochemical tracers for dust transported by wind. Fifty dust samples from 10 agriculture fields and 26 roof dust of a city close to the agricultural area were analyzed for their contents of zirconium, lead, arsenic, zinc, copper, iron, manganese, vanadium, and titanium, by portable X-ray fluorescence. Nine pesticides were analyzed in the roof dust and agricultural soil samples by gas chromatography. Results show that the distribution of metals was significantly different between active and abandoned fields. Arsenic-lead-copper was mainly concentrated in abandoned fields, while zinc-iron-manganese-titanium was dominant in active fields. Two potential sources of metal contamination were found by principal component analysis (PCA): (I) a mixture of traffic and agricultural sources and (II) a group related to agricultural activities. The occurrence of banned pesticides in dust deposited on roofs collected at nearby cities confirms the atmospheric transport from the agricultural area. The HYSPLIT results indicated that the dust emitted from agricultural fields can reach up to the neighboring states of Sonora, Mexico, and the USA. The impacts that these emissions can have on human health should be studied in future research. [ABSTRACT FROM AUTHOR]

Abstract Accumulation of heavy metals in soil can lead to the deterioration of soil quality, reduce soil fertility and crop yields, and thus threaten human and animal health. The study aimed to assess the potential ecological risk of heavy metal contamination of agricultural soils in Kazakhstan. The study was carried out in 2021 on the soils of the Zhdanovskoye owner-operated farm in the Sokolovsko-Sarybai district of the Kostanay region. The quantitative content of heavy metals, such as lead (Pb), mercury (Hg), arsenic (As), and cadmium (Cd), was determined, and concentrations of trace elements, such as zinc (Zn), copper (Cu), iron (Fe), and manganese (Mn), were calculated for the considered contaminated lands. The potential ecological risk index (RI) proposed by L. Hakanson was used in the study concerning heavy metal contamination of soil. As a result, the presence of trace elements and heavy metals in the considered areas of the Kostanay region was shown. The RI values for all sites ranged from 137 to 447, corresponding to the level of ecological risk grading from low to high. The average RI for As, Cd, Hg, Pb, Zn, Ni, and Cu amounted to 328, which indicates a high ecological risk. Detected levels of As, Cd, Zn, and Pb in long-term abandoned mining areas were well above national thresholds, indicating the impending need to fully investigate and assess the suitability of the land for further agricultural use. The availability of such data will allow predicting cluster-based development of processing infrastructures in the vicinity of agricultural lands.

Although certain trace elements are essential for normal plant functionality, an excessive increase in their concentration can disrupt plant development and physiology due to phytotoxicity. This study aims to determine the toxic tolerance limits for different concentrations of Ni and Cr (50, 100, 200, and 400 ppm) and Pb (20, 50, 100, and 200 ppm) in maize seedlings grown in soil collected near the Ferronikel smelter in Drenas, Kosovo. We will assess these limits using sensitive biomarkers, including δ-aminolevulinic acid dehydratase (ALA-D) activity, δ-aminolevulinic acid (ALA) content, chlorophyll content, glutathione (GSH) levels, and lipid peroxidation (MDA), as well as by evaluating DNA content and cell cycle dynamics. All the investigated heavy metals showed a significant increase in concentration in leaves; in particular, Ni showed a strong significant association between its concentration in treatment and in the leaves. At concentrations of 400 ppm, Ni and Cr had significant negative effects on all biomarkers, with ALA-D activity inhibited by up to 50%, and total chlorophyll content significantly decreased. A robust correlation was observed between Ni and Cr and the level of cellular oxidative stress in leaves, as monitored through GSH, lipid peroxidation, and ALA levels. Additionally, the cell cycle, especially in the G1 and G2/M phases, was arrested. These findings emphasize the significant adverse impact of high concentrations of Ni and Cr in plant metabolism. This research contributes to our understanding of managing and mitigating heavy metal contamination in agricultural areas and its potential implications for plant defense mechanisms.

The aim of this study was to determine the composition of humus in anthropogenic soils within different agroecological conditions of Istria. The research was conducted in 2020 at three soil types: Terraced soil, Gleysol and Arable soil from Terra Rossa. Soil samples were taken from each location from the arable (0-30 cm) and subarable soil layer (30-50 cm), in 5 replications. The optical density of the alkaline extract of humic substances (E4/E6) was determined spectrophotometrically (VIS). The average content of humic acids (HA) in the arable soil layer decreased as follows: Gleysoil (0.58%) > Arable soil from Terra Rosa (0.53%) > Terraced soil (0.26%). In the subarable soil layer, the highest HA was determined in Gleysoil (0.48%), followed by Arable soil from Terra Rossa (0.40%) and the lowest found in Terraced soil (0.11%). The HA/FA in both soil layers decreased as follows: Arable soil from Terra Rossa (2.28 and 1.49) > Gleysoil (1.11 and 1.09) > Terraced soil (0.39 and 0.34). In the arable soil layer E4/E6 increased from: Arable soil from Terra Rossa (1.28) < Gleysoil (1.31) < Terraced soil (4.69), and in the subarable soil layer: Gleysoil (1.43) < Arable soil from Terra Rossa (1.64) < Terraced soil (4.83). Fulvic acids of aliphatic structure and low molecular mass, which indicate a lower quality of humus, prevailed in Terraced soil with HA/FA < 1 and E4/E6 > 4. In Gleysoil and Arable soil from Terra Rossa, HA/FA > 1 and E4/E6< 4 indicated the prevalence of aromatic, highly polymerized molecular structures, i.e. the quality of humus was better.

Soil organic matter (SOM) and the ratio of soil organic carbon to total nitrogen (C/N ratio) are fundamental to the ecosystem services provided by soils. Therefore, understanding the spatial distribution and relationships between the SOM components mineral-associated organic matter (MAOM), particulate organic matter (POM), and C/N ratio is crucial. Three ensemble machine learning models were trained to obtain spatial predictions of the C/N ratio, MAOM, and POM in German agricultural topsoil (0–10 cm). Parameter optimization and model evaluation were performed using nested cross-validation. Additionally, a modification to the regressor chain was applied to capture and interpret the interactions among the C/N ratio, MAOM, and POM. The ensemble models yielded mean absolute percent errors (MAPEs) of 8.2% for the C/N ratio, 14.8% for MAOM, and 28.6% for POM. Soil type, pedo-climatic region, hydrological unit, and soilscapes were found to explain 75% of the variance in MAOM and POM, and 50% in the C/N ratio. The modified regressor chain indicated a nonlinear relationship between the C/N ratio and SOM due to the different decomposition rates of SOM as a result of variety in its nutrient quality. These spatial predictions enhance the understanding of soil properties’ distribution in Germany.

Arbuscular mycorrhizal fungi (AMF) improve plant growth and may be useful in maintaining and even restoring soil. However, data on the latter function are sparse and only indirect, which is especially true for conventional management conditions with adequate nutrient availability. Our study focused on utilizing the prevalent AMF species, Funneliformis mosseae, to enhance Glycine max production, while also exploring its partly explored impact on soil aggregation. Working in greenhouse conditions, we examined whether, in a nutrient-sufficient environment, AMF would improve crop biomass accumulation and nutrition, as well as the stability of soil aggregates (SAS). We also looked for a synergistic effect of dual inoculation using AMF and symbiotic rhizobium. Plants were or were not inoculated with AMF or Bradyrhizobium japonicum in a two-factorial design. AMF inoculation increased soybean biomass, but AMF inoculation had no impact on P and N input to the shoots. Mycorrhiza did not affect either glomalin abundance or SAS. All the impacts were, however, independent from rhizobial inoculation, which was ineffective in this nutrient-available environment. Our assay suggests that arbuscular mycorrhiza may have a positive effect on soybean growth even under conventional management with adequate nutrition. The positive effects of AMF on soybean growth, together with the fact that AMF generally do not thrive in good nutrient availability, should be taken into account when planning mineral fertilization levels.

Arbuscular mycorrhizal (AM) fungi are supposedly competing with ammonia-oxidizing microorganisms (AO) for soil nitrogen in form of ammonium. Despite a few studies directly addressing AM fungal and AO interactions, mostly in artificial cultivation substrates, it is not yet clear whether AM fungi can effectively suppress AO in field soils containing complex indigenous microbiomes. To fill this knowledge gap, we conducted compartmentalized pot experiments using four pairs of cropland and grassland soils with varying physicochemical properties. To exclude the interference of roots, a fine nylon mesh was used to separate the rhizosphere and mesh bags, with the latter being filled with unsterile field soils. Inoculation of plants with AM fungus Rhizophagus irregularis LPA9 suppressed AO bacteria (AOB) but not archaea (AOA) in the soils, indicating how soil nitrification could be suppressed by AM fungal presence/activity. In addition, in rhizosphere filled with artificial substrate, AM inoculation did suppress both AOB and AOA, implying more complex interactions between roots, AO, and AM fungi. Besides, we also observed that indigenous AM fungi contained in the field soils eventually did colonize the roots of plants behind the root barrier, and that the extent of such colonization was higher if the soil has previously been taken from cropland than from grassland. Despite this, the effect of experimental AM fungal inoculation on suppression of indigenous AOB in the unsterile field soils did not vanish. It seems that studying processes at a finer temporal scale, using larger buffer zones between rhizosphere and mesh bags, and/or detailed characterization of indigenous AM fungal and AO communities would be needed to uncover further details of the biotic interactions between the AM fungi and indigenous soil AO.

This paper aims to define a high spatial resolution model for estimating nitrous oxide (N2O) emissions from agricultural soils in Ireland. In 2020, N2O emissions from the management of agricultural soils represented 10% of the total national agricultural Greenhouse Gas (GHG) emissions. The high spatial resolution model employed here takes account of environmental factors that influence N2O emissions at a more disaggregated spatial scale than the Intergovernmental Panel on Climate Change (IPCC) national inventory-reporting framework. Activity data from the EU Farm Accountancy Data Network (for Ireland) is used in conjunction with biophysical and climatic data in a geographic information system (GIS) framework to estimate N2O emissions at a sub-national level. Results indicate that N2O emissions are 5% lower by applying this high spatial resolution modelling approach at the farm level compared to the baseline model (Tier 2). Nevertheless, 25% of the farms in the sample analysed had an overestimation in their N2O emissions of 20%, and another 25% of the farm sample had an average underestimation in their N2O emissions by 19%, a consequence of the variation of environmental factors among farms. Using a data panel regression, results confirm that the environmental factors examined are statistically significant within the model proposed, and with a simulation, we assessed the switching of 20% of CAN fertiliser for protected urea. According to the high spatial model, this mitigation measure can reduce N2O emissions from inorganic fertilisers by up to 15%. However, the reduction is conditioned by local factors and environmental conditions.

Agrochemicals are emergingly being implicated in the widespread dissemination of antibiotic resistance genes (ARGs) in agroecosystems. However, minimal research exists on the disturbance of fumigant on soil ARGs. Focusing on a typical fumigant dazomet in a simulated soil microcosm, we characterized the dazomet-triggered timely response and longstanding dynamic of ARGs at one-fold and two-fold field recommended doses using metagenome and quantitative PCR. Dazomet treatments reduced 13.17%-69.98% of absolute abundance of 16S rRNA gene and targeted ARGs, but, awfully, boosted diversity and relative abundance of ARGs up to 1.33–1.60 and 1.62–1.90 folds, respectively. Approximately 77.28% of changes in relative abundance of ARGs could be explained by bacterial community and mobile genetic elements (MGEs). Mechanistically, primary hosts of ARGs shifted from Proteobacteria (control) to Firmicutes and Actinobacteria (treatments) accompanied with corresponding changes in their abundance by combining community analysis, host tracking analysis and antibiotic resistant bacteria assay. Meanwhile, dazomet exposure significantly increased the incidence of MGEs and stimulated the conjugation of antibiotic-resistant plasmid. In addition, absolute abundance of targeted ARGs gradually recovered in the post-fumigation stage. Collectively, our results elucidate the dazomet-triggered emergence and spread of soil ARGs and highlight the importance of navigating toward rational use of fumigant in agricultural fields.

Although a few geochemical studies of agricultural soils have been conducted in southern Mediterranean countries like Morocco, such studies examining urban and sub-urban agricultural soils are very rare. The objective is to enable evaluation of different soil contamination indexes, and to identify the anthropogenic and natural sources of potential ecological risks. A sampling of nine soil samples were collected and analyzed to determine concentrations of Major elements, Rare Earth Elements (REEs) and Heavy Metals from agricultural soils of Fez-Upstream, Morocco. The major outcomes were: the average total concentration of REEs is 95.23 µg/g lower than those of the Upper Continental Crust (UCC), at 146.37 µg/g, and world soils at 137.09 µg/g; the ratios of La/Yb, La/Sm and Gd/Yb show that soil samples are enriched by light REEs. Enrichment factor (EF) and geo-accumulation index (Igeo) indicate that there is no enrichment by REEs. EF range from minimal to moderate enrichment. Igeo indicate that soil samples are unpolluted to moderately polluted. The contamination factor and degree of contamination indicate respectively moderate contamination and a low degree of contamination. Otherwise, all sampling sites have PLI values above 1 that indicate obvious anthropogenic pollution due to human activities. The results indicated that REEs contents are reflected by the parent materials. Lastly, it is interesting to note that these obtained results represent the first national data for REEs in Moroccan soils. [ABSTRACT FROM AUTHOR]

Soil salinity is one of the major causes of losses in agricultural production, which is accentuated by global warming. A sustainable strategy to mitigate the effects of the increasing soil salinisation is the use of biostimulants. In this study, the effect of a plant-based biostimulant was tested on tomato plants exposed to different salinity levels in loamy and sandy soils. Salinity in the soils reached a maximum value of 14.35 dS m−1. The treatments included a control (tap water) and a dose of 0.4 mL L−1 of the commercial biostimulant BALOX®, containing polyphenols and glycine betaine. After 60 days of treatment, several growth and biochemical parameters were evaluated in the plants, and different responses were found depending on the type of soil texture. Salt stress inhibited plant growth, mainly affecting the roots of plants not treated with the biostimulant, in both soil texture types. It also caused a reduction of total chlorophyll and carotenoid levels by 44% and 38%, respectively, under severe salinity conditions. High salinity induced a significant increase in ionic, osmotic and oxidative stress in plants, as indicated by the accumulation of toxic Na+ and Cl− ions, higher proline and MDA levels, and increased antioxidant enzyme activities. However, the application of BALOX® stimulated plant growth and root system development in all experimental conditions. The areas of roots and leaves and the stem length and diameter showed higher mean values in biostimulant-treated plants on both soil types, with more pronounced differences with the controls in sandy soils. The total fresh weight showed maximum increases of 54% and 93% on loamy and sandy soils, respectively. In addition, BALOX® significantly improved the active transport of nutrients such as K+ and Ca2+, and the concentration of photosynthetic pigments by up to 64% over control values; it also allowed greater protection against salt stress as shown by a significant reduction of proline levels, by up to 36%, and MDA by 51% under strongly saline conditions. The application of BALOX® generally decreased the level of stress in the tomato plants, promoting plant growth and enhancing their biochemical responses, even on strongly salinised soils. [ABSTRACT FROM AUTHOR]

With the popularization and high-intensity utilization of greenhouse cultivation for crops growth, the pollution of greenhouse soils has been of concern. Therefore, a national-scale survey was conducted to investigate the contamination status, sources, influence factors and the risks of polychlorinated biphenyls (PCBs) and hexachlorobutadiene (HCBD) in greenhouse and nearby open-field soils. Contents of PCBs ranged from 10−6). This study provided a full insight on the contamination status and risks of PCBs and HCBD when guiding greenhouse agriculture activities. [ABSTRACT FROM AUTHOR]

Driven by Thailand's Bio-Circular Green Economy strategy, this study explores industrial waste utilization as a solution to mitigate the impacts of climate change and economic insecurity. This study involved interviews with farmers and field sampling across 131 sugarcane plantations, primarily in four districts in Kanchanaburi, western Thailand. The investigation aimed to assess heavy metal levels (As, Fe, Mn, Zn, Cu, Cr, Pb, Cd, Hg) in the plantation soils and their accumulations in soils and biomass under various agricultural practices, including the uses of filter cake and vinasse (industrial wastes from sugar–ethanol industries). Spatial analysis showed that As often exceeded national soil-quality standards for agriculture (25 mg kg−1). The Cd, As, and Zn tended to accumulate at a high level in most soils, whereas Pb accumulated locally. Factors such as clay content, soil alkalinity (for As and Mn), soil organic matters (As, Mn, and Hg), and no/minimum tillage (Zn and Cd) promoted the metal accumulation. Factor analysis showed that natural geochemical processes govern the spatial variations of the metals. The application of filter cake led to soils with elevated Cr, Fe, As, Cd, and Mn content and a clayey organic-rich composition, while the vinasse resulted in soils with higher levels of Zn, Cu, Fe, and clayey saline. The bioconcentration factors (BCF) revealed that sugarcane generally accumulated Hg (BCF ~2.32−35.72), whereas Cu (2.67) and As (1.04) tended to accumulate in sandy-soil farmlands. The waste utilization, however, neither contributed significantly to the concern levels of soil metals nor enhanced the bioconcentration of the soil metals into the sugarcane biomass. Utilizing the waste as fertilizer could benefit cane yield, but further studies should focus on proper fertilization rates and food safety. [ABSTRACT FROM AUTHOR]