International Journal of Environmental Research最新文献

The efficacy of oxalate–phosphate–amine metal–organic frameworks (OPA-MOFs) as highly efficient slow-release fertilizers in acidic soils is well established. However, a research gap exists concerning the impact of OPA-MOFs on soils with high levels of calcium carbonate. Thus, two distinct types of OPA-MOFs with enhanced specific surface areas were synthesized and utilized in field experiments. A randomized complete block design was employed to evaluate the effect of five different fertilizers on nitrogen (N) and phosphorus (P) contents in wheat at various growth stages cultivated in calcareous soil. The treatments comprised OPA-MOF1, OPA-MOF2, IF1 (urea and triple superphosphate fertilizer), IF2 (ammonium nitrate and triple superphosphate fertilizer), and a control, each with three replications. N and P contents of the wheat plants were assessed at Zadoks growth stages 13 and 40, as well as in the wheat grains. The findings indicated that the highest grain yield was obtained with IF1 (1439.86 kg ha⁻¹), followed by IF2 (1146.83 kg ha⁻¹). In contrast, the OPA-MOF treatments yielded lower grain yields (OPA-MOF1: 1020.64 kg ha⁻¹, OPA-MOF2: 845.06 kg ha⁻¹). Moreover, OPA-MOF1 exhibited a more pronounced effect on the slow release of N and P elements due to its more regular structure, resulting in higher N content during the middle growth stage and a greater grain yield compared to OPA-MOF2.

The decomposition of returned straw is increasing facing the negative impacts by metal nanoparticles (NPs), however, which may be modulated by soil fauna and this modulation effect is unclear. Here, the interactive effects of ZnO NPs with soil fauna on wheat straw decomposition were investigated in a potted rice cropping system. The results showed that ZnO NP below middle concentrations did not significantly influence straw decomposition, and mass loss was mainly driven by microfauna and microbes. High concentrations of ZnO NPs significantly impeded decomposition, mainly by reducing the complexity of fungal communities. This negative effect was ascribed to the promotion of Zn solubilization by bacterial taxa such as unclassified Acidobacteria, Bacteroidetes and Gemmatimonadetes. ZnO NPs had a greater impact on soil microorganisms than on fauna, reduced microbial activity, promoted the released straw nutrients entering into the soil by damaging nutrient transferring microorganisms and dominated the effects on soil stoichiometry. However, soil fauna significantly increased the activities of C- and N-releasing enzymes, decreased the activity of P-releasing enzymes, regardless of ZnO NP concentration, and promoted straw C decomposition. ZnO NPs altered soil microbial community composition, but these changes were modulated by soil fauna. Nonetheless, nutrient transport by fungi such as Ascomycota and Zygomycota and grazing by fauna were the predominant modulators on straw stoichiometry. The results of this study revealed that rational control of soil fauna will be helpful for promoting straw decomposition and efficient recycling of straw nutrients by crops under ZnO NP contamination.

Two bacteria Providencia vermicola IITG20 and Pseudomonas aeruginosa IITG21 were isolated from the local refinery waste sludge and contaminated soil. They were found to be able to utilise different hydrocarbons such as diesel, petrol, kerosene and engine oil for their growth. The effect of process parameters was studied and most suitable conditions for degradation by the selected strains and their mixed culture were found to be 4% v/v initial diesel concentration, 37 °C temperature, pH 7, and 1% v/v initial inoculum concentration. The highest growth was observed for mixed culture. The lowest growth was observed for the pure culture of Pseudomonas aeruginosa IITG21. The degradation of 4% v/v diesel at 37 °C in 15 days was found to be 70 and 76% by the pure culture of Pseudomonas aeruginosa IITG21 and Providencia vermicola IITG20, respectively. Their mixed culture gave 85% degradation. The rate of degradation for diesel was highest for mixed culture compared to pure cultures. The rate constant for first order degradation was 0.154 day⁻¹ for mixed culture. It was higher compared to that of the pure culture of Providencia vermicola IITG20 (0.098 day⁻¹) and Pseudomonas aeruginosa IITG21 (0.83 day⁻¹). Accordingly, the half-life for mixed culture was lower (4.5 days) than that for pure cultures of both bacteria (7.1 and 8.3 days). These findings highlight the potential of mixed bacterial culture of Providencia vermicola IITG20 and Pseudomonas aeruginosa IITG21 for more efficient hydrocarbon degradation in petroleum hydrocarbon contaminated environments, offering promising implications for bioremediation strategies.

Climate change poses challenges to maize production and productivity in eastern Ethiopia. Impact assessment using climate predictions is the prime step to design adaptation strategies. Crop Environment Resource Synthesis (CERES)-Maize model in DSSAT (Decision Support System for Agrotechnology Transfer) was calibrated using GenCalc software. The model was used to simulate change in maize yield in the baseline (1988–2017) and future climate periods (2030s and 2050s) under (Representative Concentration Pathways) RCP4.5 and RCP8.5 scenarios using 17 CMIP5 (Coupled Model Inter-comparison Project Phase Five) GCMs (Global Circulation Models). During calibration and evaluation of the model excellent agreement of measured and simulated anthesis, and days to physiological maturity for all the cultivars with normalized root mean square error (nRMSE) of less than 10% and R² value of 0.99 was obtained. The seasonal leaf area index (LAI) and top weight progressions were also predicted well by the model with d-index of 0.96 and 0.99, respectively. Excellent (nRMSE < 10) to good (nRMSE 10–20) predictions were also obtained for grain yield and tops weight. The average annual temperature would increase by (1.90 ± 0.36) ^oC, (2.45 ± 0.53) ^oC and rainfall would increase (8 ± 5) %, (12 ± 8) % under RCP 4.5 in 2030s and 2050s, respectively across GCMs compared to baseline in the study area. As a result in 2030s yield reduction, – 10.6% to – 15.4% and – 7.4% to – 9.3% in 2050s of maize cultivar was projected across GCMs. In 2030s and 2050s under RCP4.5 and RCP8.5 long maturing cultivars (BH661) on 15th May planting with 130.5 kg N ha^–1 application predicted the highest maize grain yield.

Around 70% of surface in Extremadura, Spain, faces a critical risk of degradation processes, highlighting the necessity for regional-scale soil property mapping to monitor degradation trends. This study aimed to generate the most reliable soil property maps, employing the most accurate methods for each case. To achieve this, six different machine learning (ML) techniques were tested to map nine soil properties across three depth intervals (0–5, 5–10 and > 10 cm). Additionally, 22 environmental covariates were utilized as inputs for model performance. Results revealed that the Random Forest (RF) model exhibited the highest precision, followed by Cubist, while Support Vector Machine showed effectiveness with limited data availability. Moreover, the study highlighted the influence of sample size on model performance. Concerning environmental covariates, vegetation indices along with selected topographic indices proved optimal for explaining the spatial distribution of soil physical properties, whereas climatic variables emerged as crucial for mapping the spatial distribution of chemical properties and key nutrients at a regional scale. Despite providing an initial insight into the regional soil property distribution using ML, future work is warranted to ensure a robust, up-to-date, and equitable database for accurate monitoring of soil degradation processes arising from various land uses.

Salinity is one of the major factors that limit tomato growth and productivity, causing morphological and physiological changes and impacting plant metabolism. Seaweed extracts can reduce these harmful effects. Therefore, in this study we examined the effect of Cystoseira tamariscifolia extract (CTE) on NaCl stress tolerance in tomato plants. We assessed the effect of different concentrations of CTE on germination parameters of tomato seeds to determine the most effective concentrations. Then, we applied the chosen concentrations (2%, 5%, and 10%) of CTE as soil drench to tomato seedlings (Solanum lycopersicum L.) grown under salinity. Our findings revealed a decrease in the growth of tomato plants exposed to 50 mM of NaCl compared to unstressed ones. However, CTE supplementation, especially at 2%, to the stressed plants increased the plant height by 32.24% compared to stressed control without treatment and elevated biomass and chlorophyll content. Additionally, CTE decreased hydrogen peroxide and malondialdehyde accumulation and increased the activities of antioxidant enzymes: superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST). Moreover, CTE supplementation regulated the alterations in carbon and nitrogen metabolism by increasing the activity of carbon–nitrogen enzymes: phosphoenolpyruvate carboxylase (PEPC), malate dehydrogenase (NAD-MDH), glutamine synthase (GS), glutamate dehydrogenase (GDH), and aspartate aminotransferase (AAT). Furthermore, CTE application increased notably the content of indole acetic acid, soluble sugars, and amino acids and improved the expression of antioxidant metabolites like flavonoids and polyphenols. Overall, our investigations demonstrate that CTE can be used as biostimulant to enhance the salt stress tolerance of tomato plants.

Cadmium (Cd) contamination in rice is a global concern. Manganese (Mn) fertilizer is considered to be a compelling and practical agronomic measure to prevent Cd accumulation in grains. However, high doses of Mn are also toxic, while the effect of different forms of Mn fertilizer on reducing Cd absorption in rice remains unclear. To investigate the effects of low doses (37.5 kg/ha) of different Mn fertilizers (MnCl₂, MnCO₃, MnSO₄, respectively) applied as topdressing fertilizers in combination with alkaline fertilizers on reducing Cd accumulation in rice grown in typical acid Cd-contaminated paddy soil, field experiments were conducted. The findings indicate that the application of MnSO₄ led to a significant increase in soil pH by 0.18–0.27 units and a considerable decrease in CaCl₂-extractable Cd content in the soil, ranging from 37.01 to 31.88%. Moreover, the inclusion of MnSO₄ significantly increased the soil Toxicity Characteristic Leaching Procedure-Extractable Manganese (TCLP-Mn) content by 1.75–1.86 times, thereby promoting the antagonistic interactions between Cd and Mn ions in the rice rhizosphere. Furthermore, it substantially reduced Cd accumulation in rice grains by 6.47–14.00%. Utilizing structural equation modelling (SEM) revealed that soil pH and TCLP-Mn were identified as the major factors inhibiting Cd accumulation in grains, and there exists a direct significant positive effect of soil available Cd on the Cd concentration found within grains. Collectively, the findings suggest that applying low-dose Mn fertilizer, especially MnSO_4, as a topdressing combined with alkaline fertilizers is an economical and promising strategy for remediation of Cd contaminated paddy soil.

Graphical Abstract

Fluoride is an essential element for humans, but its excessive intake can cause harm to health. Adsorption is recommended as one of the most widely applied, affordable and convenient defluorination technologies. In the present study, Mn–Zr–Ethanol (Mn–Zr–Et) composite was prepared by sol–gel method with ethanol used as a solvent and then utilized for the fluoride removal. The removal performance of fluoride by the Mn–Zr–Et adsorbent was investigated through batch experiments. The removal mechanism of fluorine was further studied through analyzing the characteristics of the Mn–Zr–Et adsorbent. Results show that the integration of ethanol with Mn–Zr adsorbent could greatly enhance the removal capacity of fluoride when compared to the Mn–Zr adsorbent, where the adsorption capacity of Mn–Zr–Et adsorbent was 32.87 mg g⁻¹ at the initial fluoride concentration of 50 mg L⁻¹. The Mn–Zr–Et adsorbent had the advantages of fast adsorption rate, wide pH adaptation range and resistance to interference of coexisting anions. To sum up, the Mn–Zr–Et composite is a promising and green adsorbent for the highly efficient removal of fluoride.

Graphical Abstract

Presently, the main reason for global temperature rise is the increased level of carbon dioxide in the atmosphere. This increase is primarily caused by human activities, leading to carbon dioxide (CO₂) emissions that largely contribute to global warming. For better understanding of how rising temperature affects people and for studying the effectiveness of awareness programmes aimed at reducing carbon dioxide in the atmosphere, we have proposed a non-linear mathematical model. The proposed model has been extended further for controlling atmospheric CO₂ emissions as well as reducing costs associated with the execution of awareness programmes by considering variable implementation rate of such programmes over time. The strategy obtained by utilizing the optimal control theory outclasses both constant heuristic and no control strategies. Further, to illustrate the analytical findings, we have performed numerical simulations.