Search Results (35)

The fate of heavy metals in agricultural soils is governed by organo-mineral–microbial interactions, which predictive models often fail to capture. The competitive sorption mechanisms of Cd(II) and Cu(II) on montmorillonite/kaolinite composites (Mont/Kao) functionalized with humic acid (HA) and Pseudomonas putida (P. p), a model system representative of contaminated agricultural soils, were investigated. Batch experiments, XRD, FTIR, and thermodynamic analysis reveal that metal retention is a non-additive function of competing interfacial processes. Bacterial biomass dominated sorption, accounting for >50% of total metal uptake, with capacity ranked as: P. p > Mont/Kao-P. p > Mont/Kao-HA-P. p > Mont/Kao-HA > Mont/Kao. Humic acid exerts a dual, concentration-dependent role: Low levels enhanced adsorption via mineral dispersion, while high levels induced surface masking, suppressing bacterial binding sites. Competition was highly asymmetric: Cd(II) reduced Cu(II) maximum adsorption capacity by 75.5% in the Mont/Kao-HA system by preferentially occupying montmorillonite interlayer sites, whereas Cu(II) inhibited Cd(II) below pH 6. Single-metal sorption was characterized by positive ΔS° (32.96–58.89 J·mol⁻¹·K⁻¹), indicative of inner-sphere complexation, while negative ΔS° under competitive conditions signals a transition to outer-sphere complexation. This work provides mechanistic insights into site masking, competitive displacement, and ternary cation bridging controlling metal immobilization in organo-mineral assemblages. Full article

Soil organic carbon (SOC) is central to terrestrial carbon cycling, soil health and sustainable land utilization. However, in Northeast China’s black soil region, the quantitative synergistic regulatory mechanisms of soil geochemical background, climate, and topography on SOC spatial heterogeneity remain poorly understood, limiting targeted sustainable soil carbon management. This study took the Hulan River Basin with a complete soil geochemical gradient as the study area. Based on eight major soil elements and pH data, we divided the basin into five geochemical zones via PCA and K-means clustering (cumulative variance contribution: 83.02%). SOC content differed significantly among zones, peaking in strongly acidic residual-slope zones and bottoming in alkaline saline–alkali alluvial zones. Geodetector results showed aridity (q = 0.57), mean annual temperature (q = 0.50), and geochemical zone (q = 0.46) dominated SOC differentiation. The non-linear interaction between geochemical zone and aridity exhibited the strongest explanatory power (q = 0.63), far exceeding individual effects, as revealed by the interaction detector. A dual regulatory mechanism was identified: iron–manganese oxides stabilize SOC via organo–mineral complexation, while high pH and base cations accelerate SOC decomposition by disrupting soil aggregates. This study clarifies the synergistic controls of pedogeochemistry, climate and topography on black soil SOC patterns, highlighting the underestimated dominant role of geochemical background. The findings support precise regional carbon stock assessment and differentiated carbon sequestration strategies. Full article

Environmental pollution by polycyclic aromatic hydrocarbons (PAHs) is a serious environmental problem. One of the effective methods of cleaning the environment from these toxicants is the use of sorbents based on clay minerals. Special organo-mineral, bio-mineral and bio-organo-mineral complexes were obtained. Organo-mineral complexes (organoclays) were synthesized on the basis of Na-bentonite and anionic, amphoteric and nonionic surfactants. Bio-mineral and bio-organo-mineral complexes were produced by inoculating bentonite and organoclays with a consortium of bacteria. The adsorption characteristics of the complexes to benzopyrene and naphthalene were studied. Modification of bentonite with various types of surfactants leads to a significant increase in the percentage adsorption of both benzopyrene and naphthalene, with benzopyrene being more so. All bio-organo-mineral complexes adsorb more benzopyrene than pure bentonite and the bentonite + bacteria complex. In most cases, this pattern is also characteristic of naphthalene adsorption. Organoclay complexes with bacteria adsorb PAHs in greater quantities than organoclays, typically at the average concentrations of benzopyrene and naphthalene used (30–60 μg mL⁻¹) and when modified with individual surfactants. Based on the determination coefficients, the adsorption of benzopyrene and naphthalene by all studied sorbents is best described by the Langmuir equation. The maximum (limiting) adsorption of benzopyrene by all organo-mineral complexes (organoclays) exceeds the maximum adsorption of benzopyrene by bentonite. Modification of bentonite with surfactants may not change, decrease, or increase the maximum adsorption of naphthalene compared to the original bentonite, depending on the surfactant used. Colonization of the organoclay surface by bacteria, with rare exceptions, results in a decrease in the maximum adsorption values of benzopyrene and naphthalene compared to organoclay, or has no effect at all. Full article

Organo-mineral complexes are intimately involved in protecting the stability of soil organic carbon (SOC), as they are influenced by environmental factors such as pH and redox conditions, as well as by the implementation of appropriate management practices. Nevertheless, the influencing factors of organo-mineral complexes, as well as their response to tillage practices, remain poorly understood. This study investigated the effects of rotary tillage (RT), plow tillage (PT), and no tillage (NT) on organo-mineral complexes (water-dispersible G0 fraction, sodium-dispersible G1 fraction, grinding-dispersible G2 fraction) and their organic carbon (OC) in the black soil region of Northeast China in 2002 and 2022. Compared to 2002, the content of organo-mineral complexes and their OC in 2022 increased by 5.54% and 3.15%, respectively. Relative to RT, PT and NT increased the organo-mineral complex content by −0.39% and 7.98% and increased the OC content by −8.60% and 10.19%, respectively. Between 2002 and 2022, tillage measures led to greater contributions (78.71%) of organo-mineral complexes to soil carbon sequestration. In 2022, the NT treatment showed significantly higher exchangeable Ca²⁺ content than both the RT and PT treatments by 17.35% and 24.16%, respectively. Relative to RT, the PT treatment resulted in decreased levels of free and crystalline oxides of iron and aluminum, alongside increased levels of amorphous and complexed forms. By contrast, the NT treatment displayed a reverse trend. Redundancy and correlation analyses identified exchangeable Ca²⁺ in G1, pH, clay, and TP, along with iron and aluminum oxides, as key environmental factors influencing the transformation pathways among the complex fractions. Full article

Soil degradation driven by inappropriate soil management is a serious global challenge, while climate change-induced yield declines are increasing the conversion of natural ecosystems to agricultural land. This review examines how soil structure influences soil health, focusing on organo-mineral complexes derived from microbial biomass and soil organic carbon-to-clay (SOC/Clay) ratio as an indicator of structural quality. Regenerative agriculture based on conservation farming practices helps mitigate SOC depletion and aligns with the nature-based solutions framework. In Hokkaido, Japan, 10 years of clean agricultural applications (cover crops and organic matter application) increased SOC storage in farmland affected by volcanic eruption. This was associated with improved bulk density, porosity, cation exchange capacity, and phosphate absorption capacity, indicating improved soil health. The increased SOC rose SOC/Clay ratio to levels comparable with unaffected farmland (≥1/13). When the SOC/Clay ratio exceeded 1/13 (soil carbon storage level of 30 t C/ha/15 cm), carbon sequestration rate became negative. This suggests that improved soil health and structural quality may promote carbon saturation and stimulate microbial decomposition of existing SOC. While the threshold for SOC/Clay ratio varies depending on soil type, vegetation type, climatic conditions, and land use, changes in the SOC/Clay ratio can provide insights into changes in soil health and structural quality. Full article

Vegetation strongly influences soil formation, yet its effect on Rare Earth Element (REE) distribution and fractionation across treeline ecotones remains insufficiently constrained. The present study investigated how contrasting plant communities, Vaccinium myrtillus heathlands and Picea abies forests, affect pedogenetic pathways and REE behavior in sandstone-derived soils of the Northern Apennines (Italy). Six soil profiles were characterized for bulk geochemistry, selective Fe–Al extractions, particle-size distribution, and REE concentrations. Principal component analysis and hierarchical clustering identified pedogenetic drivers and horizon groupings. Under Vaccinium myrtillus, thick acidic organic horizons promoted organo-metal complexation and incipient podzolization, whereas Picea abies soils showed thinner organic layers and enhanced mineral weathering, leading to Bw development with higher silt–clay contents and elevated Al/N ratios. These pathways were captured by Fe–Al indicators and the Spodic Index. REE distributions showed vegetation-related differences in surface horizons and Eu–Ce anomalies, but they did not reproduce Fe–Al pedogenetic clusters, reflecting strong parent-material control. The coexistence of podzolic and cambic pathways at the treeline highlights pronounced spatial heterogeneity and vegetation effects. Plant composition may redirect pedogenesis, influencing nutrient cycling and metal mobility. Additionally, these findings emphasize the need to integrate multivariate statistics with established pedogenetic indicators when evaluating geochemical properties in mountain soils. Full article

This study shows that the structural features of humic acids reflect the specific characteristics of organic matter in permafrost soils of the southern Vitim Plateau. The region’s extracontinental climate determines the rate of decomposition, the depth of humification, and the chemical structure of humic acids. Brown forest soils (Haplic Cambisols) and sod-brownzems (Leptic Cambisols Skeletic) contain high amounts of organic carbon and total nitrogen in their upper horizons but differ in their vertical distribution. Brown forest soils are characterized by a sharp decrease in organic carbon content with depth and the presence of humus pockets enriched in carbon and exchangeable bases. Sod-brownzems contain more organic carbon with increase in acidity and base loss with depth. Both soil types retain satisfactory natural fertility. ¹³C nuclear magnetic resonance spectroscopy data reveal marked differences in the structural maturity of humic acids. Humic acids from the A horizons of brown forest soils contain an equilibrium combination of aliphatic and aromatic structures, a well-developed system of oxygen-containing groups, and moderate condensation, indicating an intermediate stage of humification. Humic acids from humus pockets are more aromatic and highly humified. They reflect an advanced stage of humification and possess high chemical stability. Humic acids from sod-brownzems also exhibit high aromaticity, which facilitates the formation of stable organomineral complexes. A comparison of the samples reveals a consistent increase in aromaticity, condensation, and stability from the A horizons of brown forest soils to the A horizons of sod-brownzems and further to humus pockets. This progression corresponds to an increase in humification and a decrease in the mobility and bioavailability of organic matter. These results confirm that the structural characteristics of humic acids are determined by soil type and formation conditions. Elemental composition revealed that humic acids from brown forest soils are characterized by the highest aromaticity and maturity, while humic acids from HA-brown forest soils-A have a less condensed structure. Humic acids from sod-brownzems occupy an intermediate position, combining high aromatization with a moderate degree of humification. Overall, the obtained elemental composition data are fully consistent with the results of ¹³C NMR spectroscopy, mutually confirming the identified structural features and the degree of transformation of soil organic matter. Full article

Blocking the MAPK pathway is a strategy to stop cancer cells proliferation. Despite all the successes, the acquisition of drug resistance by cells, as well as the mutational status of the downstream protein KRAS, reduces the tumor response to therapy. Ribonuclease binase from Bacillus pumilus is among the agents that block this pathway through direct interaction with EGFR and RAS. The present study is aimed at the design, optimization, and characterization of a novel complex based on antitumor binase immobilized on microgranular clinoptilolite-containing rock to ensure its prolonged release in the gastrointestinal tract. A set of modern methods including transmission electron microscopy, scanning electron microscopy, and computed tomography was used to characterize the granularity, porosity and elemental composition of the carrier. The size of binase particles, measured by atomic force microscopy at 7 nm, allows enzyme penetration into meso- and macropores of the carrier. Calorimetric results confirm that binase is stable at high temperatures, even exceeding those in the body, and retains catalytic activity in the model fluids of the gastrointestinal tract. The parameters for processing a natural clinoptilolite-containing rock and the conditions for binase sorption were selected. The gradual release of the enzyme from the carrier lasts over 20 h, which provides cytotoxicity towards human adenocarcinoma cells during movement through the gastrointestinal tract. Thus, for the first time a promising long-acting complex with antitumor and detoxifying properties was successfully created. Full article

The European Union (EU) advocates for a sustainable agricultural model with reduced synthetic fertiliser use. This study compares different high-P organo-mineral pellet fertilisers (OMFs) and their effects on crop yield. A trial was conducted under controlled conditions in ryegrass (Lollium perenne L.) pots with different organo-mineral fertilisation strategies at sowing with adjusted doses of P (120 kg P ha⁻¹) and N (200 kg N ha⁻¹). Pellets were developed from compost enriched with bone meal (OMF-BON), struvite (OMF-STR), and monoammonium phosphate (OMF-MAP). Conventional fertilisers (Complex15 and MAP) and alternative unpelletised/pelletised sources (STR and BON) were also tested. The experimental design included an unfertilised control (C), and treatments were carried out in triplicate (N = 24). Over 40 days, three cuttings (10, 25, and 40 days) were collected to determine fresh/dry biomass, nutrient content, and N, P, and K extraction efficiency. Soil labile parameters were influenced by the application of fertilisers especially OMF-MAP, OMF-STR, and MAP. MAP and STR yielded the highest nutrient extraction and biomass production, followed by their pelletised forms (OMF-MAP and OMF-STR). These results highlight the potential of pelletised organo-mineral fertilisers as sustainable alternatives to conventional sources. Full article

Crop residue returning to field inputs considerable nitrogen (N) into soils, which greatly influences the function and sustainability of the agricultural system. However, little is known about the transformation and physical stabilization of maize residue-derived N in soil matrix in response to changing N availability. To explore the distinct regulation of organo-mineral complexes on maize residue N translocation, a 38-week microcosm incubation was carried out amended with ¹⁵N-labeled maize residue in a Mollisols sampled from Gonghzuling, Northeast of China. Unlabeled inorganic N was added at different levels (0, 60.3 mg N kg⁻¹ soil (low level), 167 mg N kg⁻¹ soil (medium level), and 702 mg N kg⁻¹ soil (high level)). ¹⁵N enrichment in bulk soil and the separated particle size fractions were determined periodically in the bulk soils and the subsamples were analyzed. At the early stage of the incubation, the maize residue N concentration declined significantly in the sand fraction and increased in the silt and clay fractions. Temporally, the ¹⁵N enrichment in the silt fraction changed slightly after 4 weeks but that in the clay fraction increased continuously until the 18th week. These results indicated that the decomposing process controlled maize residue N translocation hierarchically from coarser into finer fractions. From the aspect of functional differentiation, the pass-in of the maize residue N into the silt fraction was apt to be balanced by the pass-out, while the absorption of clay particles was essential for the stabilization of the decomposed maize residue N. The inorganic N level critically controlled both the decomposition and translocation of maize residue in soil. High and medium inorganic N addition facilitated maize residue N decomposition compared to the low-level N addition. Furthermore, medium N availability is more favorable for maize residue N transportation and stabilization in the clay fraction. Comparatively, high-level inorganic N supply could possibly impede the interaction of maize residue N and clay minerals due to the competition of ammonium sorption/fixation on the active site of clay. This research highlighted the functional coupling of organic–inorganic N during soil N accumulation and stabilization, and such findings could present a theoretical perspective on optimal management of crop residue resources and chemical fertilizers in field practices. Full article

The goal of this work is to study the effect of the Natural Plant Complex (NPC) “White Pearl” on the yield and marketability of apples after long-term storage. The experiment comprised the following treatments: 1—control (without treatment); 2—foliar sprays (1% solution of “White Pearl Universal (WPU) Antifreeze” + 1% solution of “White Pearl (WP) Drip Ca + Mg”); and 3—foliar sprays (3% solution of “WPU Antifreeze” + 3% solution of “WP Drip Ca + Mg”). Foliar sprays with organomineral fertilizers (1% solution of “WPU Antifreeze” + 1% solution of “WP Drip Ca + Mg”) significantly increased (by 1.8 times) the yield of the experimental apple cultivar compared to the control. After long-term storage, foliar sprays with a 1% solution and 3% solution of NPC “White Pearl” preparations significantly reduced scald damage to ‘Sinap Orlovsky’ apples compared to the control and increased the number of marketable ‘Sinap Orlovsky’ fruits by 1.4 and 1.2 times, respectively, but the 1% solution of organomineral fertilizers was more effective. The experiment that was conducted to evaluate the effect of organomineral fertilizers in apple plantations shows that they can potentially be used to supplement traditional apple cultivation technologies. Full article

The paper hereby focuses on the essential field of soil evolution in relation to the effect of long-term fertilization on plant yields and the essential, evolutionary, and impactful changes in their fertility. NP fertilization (by application of ammonium nitrate and concentrated superphosphate) causes a change in soil reaction over time through acidification with increasing N doses, while phosphorus is able to partially mitigate this process. Acidic soil—the typical preluvosol—as a result of adsorbed acidity activation, solubilizes Al ions and may become interested in calcic amendment. Acidification tendencies are also maintained in the amended variants, but to a lesser extent due to the neutralizing capacity of the amendment and the presence of calcium ions. Complex NP fertilization in acid soil (preluvosol) cultivated with wheat can maintain a relatively constant humus content (%), but calcium amendment can cause a reduction of this indicator. In contrast, under maize, due to the effects of conventional tillage and intensive tillage, fertilization contributes to a reduction in this indicator, which is more active against the background of limestone amendment. The phenomenon can be explained by potentiation through the mineralization of the organic component of the soil. This effect is diminished in alluvial mollisol with a higher humus content, saturated in bases, and a buffering capacity. Organic and organo-mineral fertilization can control the modeling of soil humus content and its agrochemical status. The regime of essential elements (N, P, and K) becomes active in mobile forms, and the precarious supply conditions of the initial stage tend to improve. Applied superphosphate evolves, differentiated from the applied dose and pH, into non-occluded mineral forms (P-Al, P-Fe, and P-Ca), which supply the mobile forms in the soil solution for the plants, with the importance of maintaining, more of these forms at the level required by plants. In the case of potassium, the dynamics of its forms in the soil (unchangeable and exchangeable) control the soil supply state of this element and the effect of its application to plants. The data presented show that long-term experiments can effectively support the study of soil fertility through the soil-plant relationship. Full article

The Chernevaya taiga is a unique ecosystem formed under the influence of a complex of geogenic and bioclimatic factors located in the foothill border of the southeastern part of Western Siberia. The combination of local climatic conditions and the composition of parent material led to the formation of specific soil conditions on the territory of these habitats. The soils of the Chernevaya taiga have unique morphogenesis. They have a thick podzolized horizon and are fertile, unlike the typical soils of the oligotrophic pine forests of Siberia; however, the microstructure of these soils is poorly studied. The purpose of the research is to analyze the micromorphological organization and microstructure of three types of soils in Western Siberia (two typical soils from the Chernevaya taiga (Greyzemic Phaeozem (Albic) and Albic Stagnic Luvisol (Ochric)) and one from oligotrophic pine stand (Eutric Protoargic Arenosol)). It was found that the soils of the Chernevaya taiga differ greatly from the background (zonal) soils of the region on both the macro- and microlevels. In the Phaeozems and Luvisols of the Chernevaya taiga, there are actively formed organomineral aggregates and the quantity of porous media is more than 50%. At the bottom of the podzolized part of the soil profiles, we noted illuvial processes and a sharp change in the type of microstructure. The presence of pyrogenic materials (charcoal) and coprolitic (vermicular) materials in the humus-accumulative horizon indicates a high rate of material transformation and high biological activity and bioturbation in the soil. The skeleton part of the Chernevaya taiga soils is represented by a quartz–feldspar base with an admixture of sericite; augite; biotite; and a minimal admixture of tourmaline, zircon, and glauconite. Full article

The various climate scenarios consistently predict warming and drying of forests in Hungary. Soils play a significant role in the long-term sequestration of atmospheric CO₂, while in other cases they can also become net carbon emitters. Therefore, it is important to know what can be expected regarding future changes in the carbon storage capacity of soils in forests. We used precipitation gradient studies to solve this problem, using a type of “space–time” substitution. In this research, we primarily examined the quality parameters of soil organic matter (SOM) to investigate how climate change transforms the ratio of the main SOM compound groups in soils. For our studies, we applied elemental and ¹³C and ¹⁵N isotopic ratio analysis, NMR analysis, FT-IR spectra analysis, thermogravimetric and differential thermal analyses to measure SOM chemistry in samples from different oak forests with contrasting mean annual precipitation from Central Europe. Our results showed that soil organic carbon (SOC) was lower in soils of humid forests due to the enhanced decomposition processes and the leaching of Ca, which stabilizes SOM; however, in particular, the amount of easily degradable SOM compounds (e.g., thermolabile SOM, O-alkyl carbon, carboxylic and carbonyl carbon) decreased. In dry forest soils, the amount of recalcitrant SOM (e.g., thermostable SOM, alkyl carbon, aromatic and phenolic carbon and organo–mineral complexes stabilized by Ca increased, but the amount of easily degradable SOM increased further. The main conclusion of our study is that SOC can increase in forests that become drier, compensating somewhat for the decrease in forest plant biomass. Full article

Soil quality is crucial for plant productivity and environmental quality sustainability. Applying bio-organic fertilizer to achieve sustainable agriculture has become popular. Tea garden soil which had been fertilized for 12 years was chosen for the study, and soil quality and microaggregate composition were studied. The results showed that earthworm bio-organic fertilizer treatment could increase the indicators of soil’s physical and chemical properties such as total carbon and total nitrogen in soil. Bio-organic fertilization technology could significantly increase the number and activity of soil microorganisms, and upgrade soil enzyme activity which was related to soil nutrients. Specifically, the activities of urease in soil were markedly enhanced due to the implication of bio-organic fertilizer. Additionally, SR-FTIR analysis revealed that clay minerals were connected as nuclei with the capacity to bind carbon, and that this interaction was aided by organic fertilization. Specifically, the replacement of chemical fertilizer with organic fertilizer can improve the ability of clay minerals and iron/aluminum/silicon oxides to protect aliphatic groups, polysaccharides and proteins. In conclusion, continuous organic amendments initialize a positive feedback loop for the maintenance of the organic–mineral complex in soils, which can contribute to enhanced soil organic carbon (SOC) storage. These results confirmed the feasibility of organic fertilizer for soil quality improvement in tea plantation ecosystems. Full article