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Öğe Appraisal of the black carbon in soils of Harran plain, Turkey(Range Management Soc India, 2021) Sakin, Erdal; Yanardag, Ibrahim Halil; Yalcin, HamzaThis study aimed to determine Corg, Ccarb, and Crec quantities, concentrations, and stocks of soils belonging to 16 different soil series in the Harran plain, southeastern Turkey. According to the study, on average of Crec content was 0.059%, and the values varied between 0.043-0.074%. While Crec content was found highest in Sirrin and (rice series, the least was found in Akcakale, Akoren, and Kap series. When the soil series were classified in terms of Crec/ Corg ratio, it was highest in Akoren and Kap series and lowest in Irice series. Besides, there was a significant correlation between Crec and Corg, and it was observed that the level of significance was r= 0.70 (P<0.05) and above. However, no statistically significant difference (P>0.05) was observed between Harran and Bellitas, Akcakale and Cekcek, Harran and Begdes and Kap and Harran series. Although most of the Crec content in the soil comes from Corg of organic origin, it was estimated that some of it might be fossil originated and these soils are probably very sensitive to the adverse effects of organic matter decline.Öğe Biochar applications and enzyme activity, carbon dioxide emission, and carbon sequestration in a calcareous soil(Taylor & Francis Inc, 2024) Sakin, Erdal; Yanardag, Ibrahim Halil; Ramazanoglu, Emrah; Dari, Biswanath; Sihi, DebjaniBiochar is a carbon-rich product obtained by biomass pyrolysis and is considered as a means of carbon sequestration. However, there is limited knowledge regarding responses of soil respiration and C-cycle enzyme activities to BC in a calcareous soil. In this study, different biochar AS, TS, PP, CS were applied to the soil at different rates (0.5, 1.0, and 1.5%) The highest increase in soil organic C content was observed in the TS treatment, while the AS treatment caused a slight increase of soil organic C. The highest MBC content was recorded in AS treatment and the lowest was observed in TS. The highest CO2-C emission was recorded in the TS treatment. In contrast, the lowest CO2-C emission was observed in the PP treatment due to its high recalcitrant C content and was attributed to a positive priming effect, stabilizing BC mineralization to improve the soil. The highest beta-galactosidase enzyme activity was observed in the CS treatment and the lowest activity was observed in AS. The highest change in beta-glycosidase enzyme activity was observed of PP treatment and the lowest was in AS biochar application. Thus, TS treatment is recommended to increase the organic C content of soils, and the PP biochar can be used to reduce CO2-C emission. The TS, PP, and CS can be applied to increase enzyme activities. The study clearly shows that the addition of BC to arid soils may have a high potential to improve soil enzyme activities and subsequent carbon sequestration and biochemical cycles.Öğe Effects of Arbuscular Mycorrhizal Fungi (AMF) and Biochar on Cotton Plants: A Comprehensive Study(Springer Int Publ Ag, 2025) Ramazanoglu, Emrah; Yanardag, Ibrahim Halil; Sakin, Erdal; Beyyavas, Vedat; Cevheri, Cevher Ilhan; Cun, Suat; Yanardag, Asuman BuyukkilicThis study aims to investigate the effects of the combined treatment of biochar (BC) and arbuscular mycorrhizal fungi (AMF) on cotton plants, focusing on morphological and physiological characteristics, nutrient content, and soil enzyme activities. The study examined the effects of different biochar doses in mycorrhiza-inoculated (M +) and non-inoculated (M -) treatments (0% BC + 200 kg N ha(-1), 1.5% BC + 200 kg N ha(-1), 3% BC + 200 kg N ha(-1)). The results showed that the highest SPAD value (34.66%) was observed in the M( +) + 3.0% BC treatments. NDVI values increased by 25.29% in M( +) + 3.0% BC treatments. M( +) treatment increased the N, NO3-, and soil enzyme activity was higher in the M( +) treatment. However, enzyme activity decreased as BC dose increased in both M( +) and M( -) treatments, with the most significant decrease observed in the 3.0% BC treatments. Nitrate reductase enzyme activity (NRA) decreased in all treatments except the 3.0% biochar treatment. M( +) treatment increased soil urease content by 27.24% compared to the M( -) treatment. Additionally, plant height, root length, nodule count, and spore number increased with increasing biochar doses, with the highest increase observed in the M( +) + 3.0% BC treatments. Positive correlations were found between SPAD, NDVI, and nutrients such as Fe, Cu, Mn, and root attributes. Negative correlations were observed with Mg and CAT enzyme activity. Urease, DHG, and CAT enzyme activities decreased significantly with increasing BC doses, particularly in M( +) treatments. Biochar and AMF co-treatment enhanced growth, root parameters, spore count, NDVI, SPAD, and soil and plant enzyme activities in cotton plants. The combined treatment of biochar and AMF is beneficial for cotton production. The findings of this research have significant potential implications for sustainable cotton production and soil management practices, particularly in optimizing mycorrhiza and biochar to enhance soil fertility, improve water retention, and reduce the need for chemical fertilizers.Öğe Effects of Arbuscular Mycorrhizal Fungi (AMF) and Biochar on Cotton Plants: A Comprehensive Study (apr,10.1007/s42729-025-02350-x,2025)(Springer Int Publ Ag, 2025) Ramazanoglu, Emrah; Yanardag, Ibrahim Halil; Sakin, Erdal; Beyyavas, Vedat; Cevheri, Cevher Ilhan; Cun, Suat; Yanardag, Asuman Buyukkilic[Abstract Not Available]Öğe Effects of mycorrhiza and silicon on the alleviation of salt damage in salt-sensitive and salt-tolerant pepper genotypes(Polish Society Magnesium Research, 2025) Altuntas, Ozlem; Dasgan, Hayriye Yildiz; Akhoundnejad, Yelderem; Kusvuran, Sebnem; Yanardag, Ibrahim HalilSalinity is a detrimental abiotic stress that occurs in arid and semi-arid environmental conditions. Salinity adversely affects the growth, yield, and quality of plants. Some plants are sensitive to salt stress, while others are more resistant owing to the tolerance mechanisms induced by physiological, biochemical, and molecular responses. The present study was conducted to investigate the effects of mycorrhizal colonization (Glomus clarum) and silicon (Si) under different salinity levels on the activity of antioxidant enzymes, such as super oxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione oxidase (GPX) and lipid peroxidation (MDA), of salinity sensitive (cv. Demre) and tolerant (cv. Karaisali) pepper cultivars. Three diffe-rent salt doses (0 mM NaCl, 75 mM NaCl, 150 mM NaCl), with AM and 2 mM K2SiO3, were applied into 4-L vermiculite-containing pots with pepper plants. The antioxidant enzyme activities increased following the increasing salt doses. All antioxidant enzymes were observed to display differences in their activity in the two pepper genotypes that differed in salt sensitivity. Catalase, ascorbate peroxidase, and glutathione reductase activities were higher in the salt-sensitive pepper genotype. Si and mycorrhiza treatment improved the defense mechanisms in peppers, and attenuated the oxidative damage in cellular functional molecules caused by the overproduction of reactive oxygen species (ROS) under salt stress. Therefore, mycorrhiza and silicon applications, resulting in increased salt tolerance, can be used in areas with salinity problems.Öğe Electromagnetic Pollution: Effects of High-Voltage Power Lines on Soil Health and Microbial Activity(Springer Int Publ Ag, 2025) Baydilli, Eda Nur; Yanardag, Asuman Buyukkilic; Sakin, Erdal; Yanardag, Ibrahim Halil; Dilekoglu, Mehmet FatihElectromagnetic fields (EMFs) emitted by high-voltage power lines (HVLs) are an emerging environmental concern with largely underexplored implications for soil microbial functioning and biochemical integrity. This study investigates the chronic effects of non-ionizing EMFs (50-60 Hz) on soil health in a semi-arid agroecosystem of southeastern T & uuml;rkiye, focusing on microbial biomass (Cmic, N), soluble nutrient pools (Csoluble, Nsoluble, NO3-, NH4+), enzymatic activities (catalase, dehydrogenase, urease), and microbial metabolic efficiency (qCO(2)). Soil samples collected at 0 m (IR) and 300 m (control) from HVLs revealed significant alterations in microbial and enzymatic indicators. Cmic decreased by 21.8%, CAT and DHG activities dropped by 25.3% and 8.6%, respectively, while qCO(2) increased by 29.4%, indicating metabolic stress. Mechanistically, these changes are attributed to EMF-induced oxidative stress and electromechanical disruption of microbial membranes, leading to impaired enzyme function and carbon-use efficiency. Despite a slight increase in microbial N and urease activity, the overall decline in microbial resilience suggests cumulative physiological damage. These results highlight the vulnerability of soil ecosystems to electromagnetic pollution and underscore the need for long-term monitoring and mitigation strategies, such as biochar application, to safeguard soil fertility and ecosystem sustainability in HVL-exposed landscapes.Öğe Enzyme activities and heavy metal interactions in calcareous soils under different land uses(Taylor & Francis Inc, 2024) Sakin, Erdal; Yanardag, Ibrahim Halil; Ramazanoglu, Emrah; Yalcin, HamzaNovelty statementSoil health and quality, chemical degradation and restoration processes, and soils contaminated with heavy metals or potentially polluted can be good indicators of ecosystem functioning. This study was carried out with the belief that the interaction of enzymes with heavy metals in this type of soil will be revealed in detail and will shed light on such studies to be done in the future. This study was carried out to examine the interaction of enzyme activities, microbial biomass carbon, and CO2 respiration with heavy metals under different land uses in terms of quality and sustainability of the soil. There is a statistically significant positive correlation between dehydrogenase enzyme activity and Mn, Pb, Cd, and Co, while it was negative between Cr. There was a positive correlation between catalase enzyme activity and Mn and Pb and between urease and Co. The higher interaction of dehydrogenase activity with heavy metals, which is included in the endo enzyme group, has been explained as a much stronger effect of heavy metals on living microorganisms and endoenzymes than extracellular enzymes stabilized on clay minerals and organic matter. The high clay content of the soil is thought to reduce some of the negative effects of heavy metals on enzymes. The results of this study may be good indicators of enzyme activities, especially dehydrogenase, catalase, and urease, for soil health and quality, chemical degradation and restoration processes, and ecosystem functioning in soils contaminated or to be contaminated with heavy metals. It shows that the activities of these enzymes are very sensitive and can decrease rapidly in case of high concentrations of heavy metals.Öğe Growth and Biomass Responses of Cotton to Nitrogen and Molybdenum Applied via Seed, Foliar, and Soil Pathways(Springer Int Publ Ag, 2026) Cun, Suat; Firat, Zemzem; Sakin, Erdal; Yanardag, Ibrahim Halil; Beyyavas, Vedat; Cevheri, Cevher Ilhan; Yildirim, HakanThis study aimed to evaluate the effects of different molybdenum (Mo) doses and nitrogen (N) levels, applied using various application methods, on the physiological, morphological, and biochemical responses of cotton plants, as well as on soil biochemical properties. Mo (25 and 50 & micro;g kg(-)& sup1;) was applied as seed coating, foliar spraying, and soil drenching, and each Mo dose was combined with two N levels (15 and 30 kg ha(-)& sup1;). Plant growth parameters, stomatal conductance, SPAD values, leaf N content, and biomass were measured. Soil pH, EC, and enzyme activities (catalase, urease, and dehydrogenase) were also analyzed. Combined N-Mo applications significantly improved plant height, root length, leaf area, SPAD values, leaf N content, and both shoot and root biomass. Stomatal conductance decreased, thereby improving water use efficiency. Soil pH decreased while EC increased in all treatments compared to the control. Soil enzyme activities increased markedly across all Mo-N treatments, reflecting enhanced soil biochemical functioning. The Mo-N interaction positively influenced cotton physiology by enhancing photosynthetic performance, root development, nitrogen assimilation, and enzymatic antioxidant activity. Mo applications combined with appropriate N levels improved plant performance and offer a promising strategy for strengthening cotton productivity under diverse soil conditions.Öğe Mitigating Salt Stress in Cotton through Biochar Amendments: Effects on growth, Oxidative Stress, and Microbial Activity(Springer Int Publ Ag, 2026) Sarioglu, Ali; Cun, Suat; Firat, Zemzem; Sakin, Erdal; Beyyavas, Vedat; Yanardag, Ibrahim HalilPurposeThis study aimed to evaluate the effectiveness of tobacco-derived biochar in mitigating salt stress in cotton (Gossypium hirsutum L.) by assessing its impact on physiological growth parameters, oxidative stress indicators, and soil microbial activity under greenhouse conditions.MethodsA greenhouse experiment was conducted using saline and non-saline soils, with biochar applied at three doses (8, 16, and 24 g kg- 1 soil) in a randomized complete block design with three replicates. Measurements included plant growth traits (root and shoot length, biomass, SPAD values, stomatal conductance), oxidative stress markers (H2O2, MDA, proline), antioxidant enzyme activities (APX, POD, CAT), and soil enzyme activities (catalase, urease, dehydrogenase).ResultsUnder saline conditions, biochar application at 24 g kg- 1 significantly improved cotton root and shoot biomass by 30% and 25%, respectively. SPAD values and stomatal conductance increased, while H2O2 and MDA levels decreased. Antioxidant enzyme activities and microbial enzyme levels were enhanced by up to 40%, demonstrating the positive role of biochar in alleviating salt-induced oxidative stress and improving soil health.ConclusionBiochar, particularly at higher doses, enhances cotton resilience to salinity stress by improving physiological performance and microbial activity. These results highlight the potential of biochar as a sustainable soil amendment for saline agriculture.Öğe Nutrient management in calcareous soils under semi-arid environments: effects on cotton productivity and soil health(Bmc, 2026) Beyyavas, Vedat; Kara, Hasan; Sakin, Erdal; Yanardag, Ibrahim Halil; Cun, Suat; Firat, Zemzem; Ramazanoglu, EmrahIn calcareous and alkaline soils, the availability of essential nutrients is limited, leading to substantial reductions in both yield and fiber quality in cotton (Gossypium hirsutum L.) production. This study investigated the effects of different combinations of sulfur (S), zinc sulfate (ZnSO4), potassium sulfate (K2SO4), and urea on cotton yield and soil health in a two-year field experiment conducted under the conditions of the & Scedil;anl & imath;urfa-Harran (T & uuml;rkiye) Plain during the 2023-2024 growing seasons. Six different treatments were applied via soil and foliar application methods, and yield parameters (seed cotton yield, boll number, SPAD value), soil properties (pH, EC, CaCO3), and enzyme activities (catalase, urease, dehydrogenase) were evaluated. Results indicated that the combined application of elemental sulfur + ZnSO4 + K2SO4 + urea increased seed cotton yield by up to 32.9% compared with the control plots, while reducing soil pH by 4.3% and CaCO3 content by 20.8%. Moreover, catalase and urease activities exhibited changes of up to 29.7% and 15.3%, respectively. Principal Component Analysis (PCA), Partial Least Squares (PLS), and Soil Health Index (SHI) assessments revealed strong positive associations between yield, SPAD values, and microbial enzyme activities. These findings demonstrate that the integrated use of sulfur and micronutrients not only enhance cotton productivity but also contributes to improving overall soil health.Öğe Performance of Gyttja Applications to Ameliorate Saline and Non-saline Soils and Enhance Cotton Plant Growth(Springer Int Publ Ag, 2025) Sarioglu, Ali; Yanardag, Ibrahim Halil; Cun, Suat; Sakin, Erdal; Beyyavas, VedatPurpose This study examines gyttja's impact on cotton growth, oxidative stress, and soil microbial activity under saline and non-saline conditions. Methods The experiments were conducted under saline (SS) and non-saline (NS) soil conditions. Fiona cotton variety was used as the plant material. The treatments included control (non-application), gd8 (8 g), gd16 (16 g), gd24 (24 g), SS, SS + gd8, SS + gd16, and SS + gd24. Results Gyttja applications significantly improved plant growth and stress tolerance. In non-saline soil, gyttja enhanced root and shoot development, with the highest dose (gd24) increasing root length by 26.5% and shoot weight by 54.7%. In saline soil, it effectively mitigated salt stress, leading to a 62.1% increase in root length and a 142.3% increase in root weight. Additionally, the application reduced oxidative stress by lowering hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels while increasing proline accumulation. The gd24 treatment reduced H2O2 by 35% and MDA by 29% under saline conditions. Soil microbial activity was also significantly enhanced, with catalase increasing by 346% and urease by 38.2%, contributing to improved soil health and nutrient cycling. These findings suggest that gyttja is a promising organic amend-ment for improving plant resilience and productivity, particularly under saline conditions. Conclusions These results suggest that gyttja can be an effective soil amendment that supports plant health and improves soil quality.Öğe Short-Term Effects of Hemp-derived Amendments on Soil C and N Turnover and Microbial Efficiency across Three Soil Types(Springer Int Publ Ag, 2026) Yanardag, Ibrahim HalilThis study aimed to evaluate the short-term impacts of hemp-derived amendments on soil organic matter (SOM) stability, microbial functioning, and carbon-nitrogen cycling across three soil types (Entisol, Alfisol, and Mollisol). We hypothesized that amendment chemistry and soil properties would jointly influence microbial carbon use efficiency (CUE) and short-term carbon sequestration potential. Industrial hemp residue, biochar, and pyrolysis oil were applied at two carbon-equivalent doses (5 and 10 g C kg(-)(1) dry soil) under controlled 120-day incubation conditions. Cumulative CO2 emissions, dissolved organic carbon and nitrogen, microbial biomass (C and N), SOM stabilization indices, and microbial efficiency metrics (CUE, qCO(2)) were quantified. FTIR spectroscopy was used to characterize amendment chemical structures, and multivariate analyses (PCA and hierarchical clustering) were performed to identify treatment-soil interactions. Biochar markedly increased carbon retention and microbial CUE relative to hemp residue and pyrolysis oil, thereby promoting rapid mineralization and higher CO2 release. FTIR analysis confirmed the presence of stronger aromatic and condensed structures in biochar, indicating greater recalcitrance. Soil type strongly modulated amendment effects: Alfisol exhibited the highest microbial efficiency, whereas Entisol showed the most labile C turnover. Differences were linked to pH, texture, and inherent SOM content. Hemp-derived amendments can enhance short-term SOM stabilization and microbial efficiency, but their effectiveness depends on both amendment chemistry and soil type. Biochar showed the most tremendous potential to improve carbon management, while residue and pyrolysis oil stimulated rapid nutrient cycling. These findings highlight the value of soil-specific strategies when using hemp-based organic inputs to improve soil health.Graphical Abstract Key Insights from the Graph: Hemp Biochar (BC1 & BC2) treatments show the highest carbon sequestration while also reducing CO2 emissions significantly.Hemp Residue (Hemp1 & Hemp2) and Pyrolysis Oil (BC Oil1 & BC Oil2) lead to higher CO2 emissions, meaning they contribute to short-term microbial activity but not long-term sequestration.Microbial efficiency (CUE ratio) is highest in biochar-treated soils, reinforcing its role in long-term carbon stabilization.Öğe Strategies for the Sustainable Management of the Organic Fraction of Municipal Waste(Mdpi, 2022) Dolores Gomez-Lopez, Maria; El Bied, Oumaima; Carlos Beltra, Juan; Yanardag, Ibrahim Halil; Gomez, Cristina; Faz, Angel; Zornoza, RaulThe organic fraction of municipal waste, OFMW, management is one of the main concerns for urban waste managers in developed countries. Composting this biodegradable urban waste and using the compost in agricultural activities is a quickly growing method and is a viable option to manage urban waste in both the developed and the developing world. This research presents the example of the management proposal for Cartagena city in Spain, in which the technical and environment feasibility has been studied. This work aimed to evaluate the composting of a mixture of different residues, namely organic waste, pruning, and Posidonia oceanica (L.) Delile, which was collected from the beaches of the municipality while cleaning. Mixtures 1, M1 (composed of 20% OFMW and 40% pruning and seaweed) and 3, M3 (composed of 30% OFMW and 70% pruning) proved to be the best to reach the ideal compost (1.23-0.08-1.28 NPK and 2.22-0.33-3.45 NPK, respectively). An extreme mixture, M2, was evaluated (50% PO; 50% pruning) but poor results were obtained due to a non-optimal initial C/N by not containing OFMW. At the same time, the volumes by urban nucleus and the viability of different composting strategies have been studied, proposing that 180,000 inhabitants use the centralized composting plant and almost 31,000 inhabitants use self-composting and community composting. Considering the carbon footprint of this management, the value was 50% lower than the total management in a centralized plant. Moreover, the final use of compost is optimum with self-composting and community composting because it is nearest to agricultural consumptions, also reducing the transport of the final product.Öğe The effect of arbuscular mycorrhizal fungi on biological activity and biochemical properties of soil under vetch growing conditions in calcareous soils(Cell Press, 2024) Burak, Kader; Yanardag, Ibrahim Halil; Gomez-Lopez, Maria Dolores; Faz, Angel; Yalcin, Hamza; Sakin, Erdal; Yanardag, AsumanDue to soils from arid regions with high lime and low organic matter content, farmers receive low yields along with high costs of agricultural inputs, which causes them to look for a solution. In this context, Arbuscular mycorrhizal fungi (AMF) have great potential to reduce fertilizer use by mediating soil nutrient cycles. However, little is known about studies of AMF inoculum on microbial biomass carbon (C), nitrogen (N), and phosphorus (P) cycling during vetch plant vegetation in calcareous areas. In this study, changes in soil biogeochemical properties related to soil C, N, and P cycling were investigated with five different AMF inoculations under vetch (common Vetch (CV; Vicia sativa L.) and Narbonne Vetch (NV; Vicia narbonensis L.) growing conditions. For the field study, a total of five different mycorrhizae were used in the experiment with the random plots design. AMF inoculation decreased the lime content of the soil, and the highest decrease was observed in NV with Glomus (G.) intraradices + G. constrictum + G. microcarpum inoculation (24.41 %). The highest MBC content was recorded in CV vetch G. intraradices (1176.3 mg C kg -1) and the highest MBN content in NV vetch G. intraradices + G. constrictum + G. microcarpum (1356.9 mg C kg � 1). CAT activity of soils was highest in CV vetch G. intraradices (31.43 %) and lowest in NV vetch G. intraradices + G. constrictum + G. microcarpum (72.88 %), urease enzyme activity decreased in all treatments except G. constrictum + Gigaspora sp. and G. mosseae inoculations in CV. The highest DHG activity was detected in GF (15.72 %) AMFs in CV and GI (21.99 %) in NV. APA activity was highest in Glomus constrictum + Gigaspora sp. (23.33 %) in CV and Glomus fasciculatum (10.08 %) in NV. In CV plots, G. intraradices + G. constrictum + G. microcarpum (91.67 %) isolates had the highest and G. intraradices community had the lowest RC% (97.33 %) in mixed mycorrhiza species, while in NV plots G. fasciculatum inoculum had the highest and G. intraradices community had the lowest RC%. This study has important implications for the application of AMF for sustainable agriculture. When the results of the study were evaluated, the most effective AMF isolates in terms of C, N, and P cycles were G. constrictum + G. fasciculatum + Gigaspora sp. in Common vetch variety, and G. intraradices in Narbonne vetch variety.Öğe The influence of micronized sulfur amendments on the chemical properties of the calcareous soil and wheat growth(Taylor & Francis Inc, 2023) Sakin, Erdal; Yanardag, Ibrahim HalilHigh soil pH constrains the availability of many plant nutrients including phosphorus (P). Sulfur (S) application to soil is a commonly used method to reduce the soil pH in the plant root zone, increase the availability of nutrients and thus obtain a higher yield. However, the particle size of the S is the most important factor in decreasing the soil pH. This study aimed to investigate the effect of different doses of micronized S application (0, 125, 250, and 375 kg ha(-1)) on the chemical properties of calcareous soil and the yield and nutrient contents of two wheat cultivars (Burgos and Zhivago). The results indicated that soil pH and CaCO3 content of soil decreased with increasing doses of S application. Soil organic carbon content slightly increased with all S applications in Burgos wheat variety. The highest increase was recorded in the 375 kg ha(-1) S application, but no significant difference was determined in the Zhivago variety. The available Cu content in soil varied between 3.43 and 3.55 mg kg(-1), Fe content was between 13.86 and 14.93 mg kg(-1), Mn content was between 22.73 and 25.65 mg kg(-1), and Zn content was between 0.53 and 0.62 mg kg(-1). The results revealed that soil pH and CaCO3 content decreased with liquid micronized S applications, however, the effect of S applications on exchangeable cations and heavy metal content was not significant.Öğe Unseen threat: The devastating impact of microplastics on soil health in agricultural lands(Elsevier, 2025) Sakin, Erdal; Dilekoglu, Mehmet Fatih; Yanardag, Ibrahim HalilMicroplastic pollution, originating from synthetic polymer materials, is a growing environmental threat with substantial implications for soil health and ecosystem functionality. This study investigates the accumulation and impacts of microplastics from plastic greenhouse covers on agricultural soils. Soil samples were collected from five greenhouses established 10 to 30 years ago, at a depth of 0-30 cm, to evaluate microplastic contamination levels and their impact on soil parameters. Microplastics were extracted using density separation with a saturated NaCl solution, followed by microscopic analysis for quantification. Enzyme activities, including beta-glucosidase, beta-galactosidase, beta-glucoaminidase, urease, dehydrogenase (DHG), and catalase, were measured using spectrophotometric and colorimetric assays. Microplastic concentrations ranged from 47 to 315 particles per 5 g of soil, with a progressive increase in concentration linked to the age of the greenhouses. Results revealed significant alterations in soil pH, which ranged from 7.58 to 8.04, and electrical conductivity (EC), varying between 192 and 616 mu S cm(-1). Organic carbon (0.68-0.59 %) and total nitrogen (0.07-0.03 %) contents decreased in soils with increasing microplastic concentrations, while microbial biomass carbon (Cmic) and nitrogen (Nmic) decreased by 43.75 % and 46.59 %, respectively. Enzyme activities such as beta-glucosidase, beta-galactosidase, and beta-glucosaminidase declined by up to 51.17 %, 30.90 %, and 28.31 %, respectively. Additionally, soil respiration (CO2-C emissions) increased by 73.91 % (0.19 to 0.33 mg CO2-C kg(-1) soil h(-1)), and the metabolic quotient (qCO(2)) rose by 239.82 % (1.41 to 4.82 mg CO2-C g(-1) Cmic h(-1)). Regression analyses demonstrate strong correlations between microplastic concentrations and soil property changes, with a one-unit increase in microplastic concentration leading to significant decreases in enzyme activities (p < 0.05). Additionally, long-term microplastic accumulation altered soil structure, increasing porosity and aggregate instability, which compounded the reduction in enzyme activities. These findings underscore the profound negative effects of microplastic pollution on soil ecosystems, emphasizing the urgent need for sustainable agricultural practices and effective waste management strategies to mitigate microplastic contamination and its detrimental impact on soil health and functionality.
