Search Results (290)

Per- and polyfluoroalkyl substances (PFASs) are persistent, surface-active contaminants for which soil represents the largest terrestrial reservoir. This review synthesizes a rapidly expanding but fragmented body of literature in order to reframe PFAS not merely as a groundwater transport problem but as a systemic stressor of soil health, drawing together their reported effects on the chemical, physical and biological properties of soils and giving particular attention to the calcareous, alkaline, carbon-poor and seasonally dry soils of the Mediterranean. The reviewed evidence suggests that, chemically, PFASs perturb the coupled carbon and nitrogen cycles rather than the bulk soil reaction, transiently stimulating and then depressing organic carbon turnover, drawing down the dissolved organic carbon pool and disturbing nitrification, while their retention and bioavailability are governed chiefly by organic carbon, chain length and pH. Physically, the surfactant character that defines these molecules lowers the surface tension of soil water and concentrates PFASs at the air–water interface, so that in unsaturated and drought-prone soils much of the burden is retained and then released episodically, most clearly on rewetting after dry periods. Biologically, the literature consistently reports dose-dependent declines in microbial viability, diversity and enzyme activity, alongside toxicity to earthworms and other soil fauna, with sensitivity strongly modulated by soil texture and organic matter. Across all three domains, the Mediterranean emerges as both potentially vulnerable and conspicuously understudied, the available data being clustered in a few western countries and effectively absent for much of the eastern and southern basin, so that the regional assessment offered here rests largely on mechanistic inference rather than on direct observation. The review argues that these coupled mechanistic and geographic gaps define an urgent, region-specific research agenda for the protection of soil health. Full article

The physicochemical properties and applicability of cow manure biochar (CMB) as a soil conditioner and horticultural substrate amendment for halophyte growing on deteriorated coastal soils were assessed in this study. A typical commercial substrate (50% coco peat, 25% peat moss, 12% perlite, 7% vermiculite, and 6% zeolite) was used to compare elemental composition, thermal stability (TGA/DTG), surface morphology, pore structures (BET, FESEM), and functional groups (FT-IR) of CMB. In addition, 10% (w/w) CMB was added to coastal soils in the Saemangeum and Sinan-gun regions in order to assess changes in the physicochemical soil quality. In comparison to the commercial substrate, the analytical results showed that CMB had higher concentrations of essential mineral elements (such as K, Ca, P, Zn, and Na), a higher proportion of carbon (25.69%), and more accessible phosphorus (3490.97 mg/kg). Additionally, compared to the commercial substrate, CMB showed a nearly 19-fold larger specific surface area (77.53 m²/g) and increased micropore volume, suggesting better potential for soil aeration and water retention. Cultivating halophytes (Salicornia herbacea L. (glasswort) and Suaeda japonica Makino (seepweed)) in a 9:1 (v/v) substrate-to-CMB mixture for five weeks resulted in successful early germination and robust seedling establishment. Incorporating 10% CMB into coastal soils also substantially increased available phosphorus, total organic carbon (TOC), and organic matter (OM), demonstrating CMB’s effectiveness in enhancing nutrient availability and supporting soil carbon sequestration. All things considered, this study offers a practical framework for using biochar made from livestock manure as a sustainable substrate supplement to reclaim degraded coastal environments and advance biosaline agriculture. Full article

Degraded industrial sites in arid and semi-arid regions often suffer from loose surface substrates, weak water-retention capacity, high wind-erosion risk, and poor early vegetation establishment. Combining photovoltaic (PV) deployment with ecological utilization may improve near-surface habitats by shading, reducing wind speed, and regulating soil heat and moisture. This study investigated an ash storage yard of a coal-fired power plant in Ordos, Inner Mongolia, China, by comparing soil temperature, soil moisture, and near-surface wind-speed responses under three representative fixed PV tilt angles of 36°, 43°, and 50°, together with the corresponding early plant-growth suitability. A multi-physics model coupling near-surface airflow, water-vapor transport, and porous-media hydrothermal migration was established. A Gaussian suitability function combined with AHP-CRITIC weighting was used to construct a model-based comprehensive growth index (CGI) from soil temperature and moisture, while short-term field monitoring was used to validate afternoon soil hydrothermal trends. Among the three scenarios, the 36° configuration produced the widest horizontal heat–moisture-affected zone and the highest CGI values for alfalfa and Elymus nutans, reaching 0.7741 and 0.6875, respectively. Relative to the outside reference area, the rear PV zone reduced the near-surface wind speed by 33–40% and increased the plant heights of alfalfa and Elymus nutans by 49.4% and 37.8%, respectively. A first-order PVsyst assessment showed that the 43° configuration achieved the highest specific energy yield of 1814 kWh kWp⁻¹ year⁻¹, whereas the annual grid-connected output at 36° was only 0.59% lower. These findings indicate that the 36° configuration may provide a favorable compromise between early vegetation establishment and photovoltaic electricity generation among the tested scenarios. By linking renewable-energy production with microenvironment regulation and early vegetation establishment, the proposed framework provides a decision basis for the multifunctional and sustainable reuse of degraded industrial land. Nevertheless, the results represent a site-specific, single-season assessment and should not be interpreted as a universal optimum. Full article

In this study, we synthesized a lignin-based superabsorbent hydrogel (LWR) to relieve severe evaporation and structural degradation in inland saline–alkali soils. The LWR was prepared via free-radical graft copolymerization of calcium lignosulfonate (CL) and acrylic acid (AA), with its swelling performance optimized systematically. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize its chemical and microscopic structure, and the soil column was exposed to three drying–wetting cycles to explore the effects of hydrogel dosage on soil evaporation and crack evolution. CL may graft into polyacrylic acid under optimal conditions (60% AA neutralization, 4% CL, 1% initiator, and 0.03% crosslinker) to form a porous hydrophilic 3D network. Consequently, the optimized LWR achieved swelling capacities of 1480 g/g and 122 g/g in deionized water and a 0.9% NaCl solution, respectively, showing high water absorbency and salt resistance. During cyclic drying and wetting, soil evaporation was first dominated by the hydrogel’s water retention capabilities; then, it was controlled physically by soil surface cracks. A moderate LWR dosage of 0.3% was used to maintain stable water retention in soil and the intact soil structure, which likely occurred due to its strong water absorption and hypothesized calcium ion bridging anti-cracking interactions. This work overturns the traditional view that a higher hydrogel dosage yields better water retention. Instead, it highlights the importance of conducting a long-term joint evaluation of the hydrogel’s water retention capacity and its resistance to soil dry–wet deformation stress, thereby offering theoretical support for eco-friendly water retention agent design and saline–alkali land remediation. Full article

Water scarcity, high non-productive soil evaporation, and poor vegetation establishment are major constraints on the sustainable ecological restoration of reconstructed open-pit mine dumps in arid and semi-arid regions. Conventional surface-applied water replenishment can result in rapid evaporative loss, thereby reducing the ecological benefits obtained from limited water resources. However, whether redistributing water into deeper reconstructed soil layers can simultaneously reduce non-productive evaporation, stabilize the root-zone hydrothermal environment, and improve vegetation growth remains insufficiently verified. In this study, a deep-profile soil water replenishment (DPSWR) device was tested in reconstructed mine-dump soil columns planted with locally adapted Stipa. Surface-applied water replenishment (CK) and DPSWR were compared using a single-run simulated rainfall comparison, soil water-retention and water-loss measurements, continuous temperature and moisture monitoring at 10 and 40 cm depths, and plant growth indicators. In the rainfall-simulation comparison, DPSWR showed lower cumulative water loss across the tested rainfall intensities and improved water-retention stability; the evaporation rate under CK was approximately 1.3 times that under DPSWR, whereas final soil water-holding capacity under DPSWR was approximately 2.4 times that under CK. Root fresh weight, plant fresh weight, and seedling number were significantly higher under DPSWR than under CK (p < 0.01), and maximum plant height and root length also increased significantly (p < 0.05). Under equal water-input conditions, DPSWR reduced non-productive water loss, prolonged soil water retention, and supported vegetation establishment. These findings suggest that DPSWR may provide a more water-efficient approach to the sustainable restoration of reconstructed mine dumps in water-limited regions. Full article

The surface soil in the Shendong mining area is dominated by aeolian sand and sandy sediment, while precipitation is limited, and evaporation is intense. Under these conditions, shallow reconstructed soil has difficulty retaining plant-available water, which constrains vegetation restoration. This study evaluated how low-range increases in fine-particle clay content affect both water retention and upward water conduction in sandy reconstructed soil. Sandy material from the Shangwan mining area and exogenous river clay were mixed into four treatments, and soil water characteristic curves (SWCCs) were determined by centrifuge over 10–1000 kPa matric suction. The data were fitted with the Van Genuchten model and combined with capillary-rise tests. The results showed that increasing fine-particle content shifted the SWCC upward and raised both saturated and residual volumetric water contents. SN10 reached 17.18% and 5.55% volumetric water content at 10 and 1000 kPa, respectively, and its effective water capacity in the 33–1500 kPa range was 17.9% higher than that of ST. At the same time, fine-particle enrichment in the bottom layer reduced wetting-front rise during capillary testing, indicating a trade-off between water storage and upward replenishment. Within the tested fine-particle range, moderate clay addition improved the hydraulic performance of sandy reconstructed soil, but soil design should balance precipitation retention, infiltration, and capillary supply. Because each treatment and soil-column configuration was represented by only one independently prepared experimental unit, experimental variability and reproducibility could not be evaluated. This study should therefore be regarded as a preliminary and exploratory laboratory assessment conducted under a specific set of material-preparation procedures, specimen geometries, and boundary conditions. The results describe specimen-level hydraulic contrasts rather than reproducible treatment effects and should not be directly generalized to field-scale soil reconstruction. They support a preliminary hypothesis for future replicated testing: fine-particle enrichment may increase water retention while slowing upward capillary replenishment. Full article

This paper reports a research work on assessing clay content effect on the water retention capacity of clayey sandy soils. At first, experimental tests were conducted to measure the soil water retention curves (SWRCs) of clayey sandy soils. A total of four different soil samples, which have clay content of 0, 15, 30 and 50%, respectively, by total soil sample weight, were measured. Secondly, a revision of a physical–chemical (PC) analytical model previously proposed has been reviewed and adopted to represent the SWRC measurements and compared for its predictive performance against the classic van Genuchten model and the original PC model. The experimental results demonstrated that clay content has a significant influence on soil water retention capacity, showing that a positive correlation generally exists between them. The modelling results showed that the revised analytical model not only produced a good representation for the soil water retention curves over whole range of soil water content, particularly at low water content side, but also provided advanced insight into the fundamental physics underlying soil water retention mechanisms. The analysis of its parametric data highlights the functions of the involved physics and their roles shaping the SWRCs, which intrinsically relate to specific surface area, pore size distribution, and particle size and shape. At last, the model was used to describe the pore size distribution from a revised concept against conventional approach. However, the revised concept and approach needs further wide verification and is open for discussion. Full article

The impact of biochar on N conversion in drought-affected soil with green manure application has not been systematically investigated. Therefore, this study examined the effects of biochar produced at 350 °C, 550 °C, and 750 °C (BC350, BC550, and BC750) on green manure (Medicago sativa L.) decomposition and N turnover in soil (Hapli-Udic Ferralosol) during a 60-day laboratory incubation experiment under different moisture conditions (45% or 65% soil water-holding capacity (WHC)). Due to low-temperature biochar (BC350) possessing hydrophilicity (thereby enhancing water retention) due to its surface oxygen-containing functional groups, while high-temperature biochar (BC750) relies on the aromatic conjugated π-electron system for electron transfer, both BC350 and BC750 promoted green manure decomposition and mineralization. Compared with green manure alone, co-application of BC350 and BC750 with green manure increased soil NH₄⁺–N content by 5.58% and 38.37%, respectively. However, a significant total N loss (>11%) occurred under drought conditions. Partial least squares path modeling was used to elucidate the key driving pathways related to C and N sequestration in drought-affected soil with green manure and biochar co-application. The results indicate that the enhanced soil N loss could be attributed to both the biochar-induced rise in soil pH (>8%) and the drought-driven suppression of stable organic matter (e.g., >20% reduction in humus acid) and macroaggregate formation. This study demonstrates that although biochar addition can promote the decomposition of green manure to release available N, it may also exacerbate total soil N loss. Only under normal moisture conditions can the N released from green manure be converted into humus-associated N. Full article

The possibility of implementing intelligent irrigation has a number of undeniable advantages, mainly including the fact that the time can be determined and the volume of irrigation water can be adapted to specific plant types on a specific soil. A neural network has been trained to describe the dynamics of soil moisture based on the basic soil water retention curve (SWRC). It is able to take into account a wide range of input data, such as the specific surface area of the solid phase of soils, porosity, humidity, etc., for a given initial soil moisture profile. Preference is given to a recurrent neural network, since this type works well with sequential data and is able to take into account time dependence and solve the problem of decaying gradients of soil hydrophysical properties. The neural network processes the vector of incoming signs—humidity, temperature, volume of incoming/outgoing water, etc.—and connects them with the dynamics of humidity from sensors located at different depths. When modeling mass–salt transfer with different boundary and initial conditions, the dependence of moisture retention on the moisture conductivity function is used, which allows us to calculate how moisture with dissolved nutrients moves through the soil under the influence of pressure and concentration gradients. Since the SWRC is constructed as a function of directly measured data, it is easy to set it for each point of interest in the field and at each depth. During modeling, the soil is divided into elementary volumes (from 2–3 mm to 1 cm), and an array with data sets is compiled at each point. The research was conducted in a real hop plantation (the village of Opytny, Tsivilsky district, Republic of Chuvashia). The values of the soil moisture sensors at different depths, together with the data from the portable weather station, are sent to the input of the neural network. According to the minimum allowable humidity for hops, the model predicts situations when humidity reaches critical values and initiates watering. Thus, the implemented approach makes it possible to automate irrigation management, increase water use efficiency and ensure optimal conditions for plants. Full article

Water limitation during soybean (Glycine max (L.) Merr.) establishment restricts leaf expansion and root–shoot development, whereas microbial biostimulants may modify these responses only within particular moisture contexts. We tested whether a mixed-species suspension of Bacillus subtilis and Bacillus amyloliquefaciens produced water-regime-dependent dose responses in a controlled-environment tray-cell experiment. The seedlings received a single rhizosphere-directed application of 0, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.75 or 2.0 mL of undiluted inoculum per cell before exposure for 15 days to full irrigation (W100), 50% or 25% of the W100 replacement volume (W50 and W25), or no irrigation (W0). Each of the 44 treatment combinations comprised six independent biological replicates (264 cells). Two-way ANOVA detected significant water-regime, dose and interaction effects for most thermal, growth, biomass and allocation traits, with water regime as the dominant source of variation. Averaged across doses, relative to W100, W0 increased the leaf-surface temperature by 8.8% and reduced the root length by 44.3%, shoot length by 25.4%, stem diameter by 38.2%, leaf area by 72.3%, total dry mass by 20.1% and specific leaf area by 70.4% on average. The concurrent 17.3% increase in the leaf mass fraction indicated the retention of proportional leaf dry-matter investment despite strongly restricted surface expansion. The bacterial response was non-linear and water-regime-specific. Within W0, 0.05 mL increased root dry mass by 116.7% and total dry mass by 39.3% relative to the untreated W0 control. The highest integrated mean z-score occurred at 0.05 mL under W0, 0.2 mL under W25, 1.2 mL under W50 and 0.2 mL under W100. Correlation analysis identified coordinated trait covariation, whereas hierarchical clustering and principal component analysis separated a warm, low-expansion W0 phenotype from a cool, high-vigour W100 phenotype. These findings provide a quantitative experimental basis for selecting candidate pre-drought doses for seedling-stage screening. Validation across soils, application timings, formulation persistence and reproductive-stage yield are required before commercial recommendation. Full article

The accumulation of shipwrecked wood in coastal ecosystems represents an important environmental challenge due to its effects on coastal dynamics, ecosystem functioning, and waste management. The valorization of this lignocellulosic residue through thermochemical conversion offers a sustainable alternative for transforming an underutilized biomass into value-added products. This study evaluated the potential of biochar produced from shipwrecked wood collected in the Punta Roca sector, municipality of Puerto Colombia (Atlántico), as an organic soil amendment. The methodology included the physicochemical characterization of the biochar, as well as analysis of its specific surface area (BET), morphology (SEM), and elemental composition (EDAX). Among the most relevant physicochemical results, the biochar exhibited an organic matter content of 87.85%, an alkaline pH of 10.29, and low moisture content (9.21%), suggesting stability and the capacity to modify soil acidity. Regarding specific surface area, the BET area increased significantly from 0.77 m²/g in untreated wood to 61.61 m²/g in the biochar, indicating a notable enhancement in adsorption capacity. Porosity analysis revealed a decrease in pore size, which may favor the retention of nutrients and water. Elemental composition analysis revealed a high carbon content (82.65%) and oxygen content (15.32%), accompanied by trace amounts of elements such as Na, Mg, Si, Cl, K, and Ca. These results confirm that biochar derived from shipwrecked wood possesses physicochemical characteristics suitable for application as an organic amendment in agricultural soils. Overall, these findings demonstrate that biochar derived from shipwrecked wood is a promising alternative not only as an organic soil amendment but also as a strategy for coastal waste valorization, the promotion of circular economy principles, and the development of more sustainable agricultural systems. Full article

Sandy desert ecosystems of Central Asia are highly vulnerable to climate change, land degradation, and increasing anthropogenic pressure, yet the soil conditions supporting native desert vegetation remain insufficiently characterized. This study investigates soil development and physicochemical properties under the canopy of Calligonum aphyllum across different geomorphological conditions in the southern Balkhash region of Kazakhstan. Field investigations were conducted within the Ili River delta, where nine soil profiles were described across three geomorphological settings. Soil samples were analyzed using standard soil analytical methods to assess particle-size composition, soil organic matter, nutrient availability, carbonate content, salinity, and sodicity indicators. The studied soils were predominantly sandy, with sand fractions ranging from 88 to 96% and very low clay content, resulting in weak horizon differentiation, high permeability, and limited water-retention capacity. Soil organic matter and total nitrogen contents were consistently low across all sites. Available phosphorus decreased with depth, particularly in carbonate-enriched horizons, whereas exchangeable potassium remained comparatively high. Total salinity was low, with chloride–sulfate and calcium–sodium dominance, and no evidence of sodicity was observed based on SAR values. Clear differences among geomorphological settings were identified, including relatively homogeneous sandy substrates, dust-enriched semi-stabilized sands, and actively reworked aeolian ridges. The results indicate that C. aphyllum can persist under nutrient-poor, coarse-textured sandy conditions and is associated with surface root concentration, local substrate stabilization, and early soil-profile differentiation. These findings highlight the ecological importance of C. aphyllum in sandy desert habitats and provide site-specific soil information relevant to vegetation-based restoration and sustainable land management in arid regions of Central Asia. Full article

Stable rice production is critical for ensuring national food security and agricultural sustainability. Climate change is increasing the demand for efficient crop management strategies to maintain rice production. Foliar fertilization enables rapid nutrient supplementation by directly delivering nutrients to aboveground tissues while avoiding soil-related limitations. However, most foliar formulations are primarily designed for rapid nutrient delivery and have limited capacity to prolong water retention and nutrient availability on leaf surfaces after application. Hydrogels possess excellent water-retention and nutrient-delivery capabilities, but their intrinsic crosslinked networks limit water solubility and foliar suitability. Inspired by these characteristics, a sprayable polymer-based formulation was designed to combine hydrogel-like moisture preservation with foliar application compatibility. In this study, a foliar moisture-preserving synergist (FMPS) was developed using radiation-synthesized potassium polyacrylate as the polymer matrix, with urea and glucose incorporated as nitrogen and carbon sources, respectively. Structural characterization revealed morphological changes after incorporation of urea and glucose into PAA-K, while Fourier transform infrared spectroscopy suggested their incorporation and possible intermolecular interactions. Under standard growth conditions, FMPS increased the effective panicle number, filled grain number, and seed-setting rate by 29.3%, 18.4%, and 4.0%, respectively, resulting in significantly improved rice yield. These findings demonstrate the potential of FMPS as a hydrogel-inspired foliar formulation for enhancing rice productivity. Full article

The Bajo Sinú Wetland Complex (CCBS for its acronym in Spanish) constitutes one of the most critical marsh systems in the Colombian Caribbean and represents one of the most relevant hydric ecoregions in the country. Therefore, this study aimed to evaluate and map the relative provision of ecosystem services in the CCBS through the implementation of the ECOSER protocol. Using cartographic models, the specific requirements necessary to map seven of the nine ecosystem functions included in the ECOSER protocol that proved critical for the CCBS were defined: soil organic carbon storage, biomass carbon storage, erosion control, soil fertility, retention of excess precipitation by vegetation cover, retention by wetlands, and nutrient retention. The results demonstrated that the CCBS possesses significant potential for soil organic carbon (SOC) sequestration, exhibiting an average content of 18.9 Mg C ha⁻¹, with grasslands and marshland covers recording the highest values. Regarding biomass carbon storage (BCS), average values reached 12.85 Mg C ha⁻¹. These findings confirm the high capacity of wetlands to store carbon, thereby contributing significantly to climate regulation. Furthermore, the analysis of the soil fertility ecosystem function showed high productivity levels, with soil profiles exceeding 70% of the maximum potential value. Conversely, although the biophysical analysis revealed a moderate water regulation capacity by retaining approximately 15.4% of the annual precipitation, which corresponds to 170,067,986 m³, this function plays a fundamental role in minimizing surface runoff and mitigating flood risks across the territory. Full article

In modern livestock production, a reliable supply of high-quality forage is essential for sustaining animal productivity and product quality. Although nitrogen (N) fertilization can promote forage growth, excessive N inputs often result in low agronomic nitrogen use efficiency (NAUE) and increased environmental risks. Biochar, owing to its porous structure, high specific surface area, and physicochemical stability, can improve soil physical properties, enhance water and nutrient retention, and regulate soil N availability. However, the mechanisms by which biochar combined with reduced N rate fertilization affects NAUE in artificial grasslands remain insufficiently quantified. A two-year field experiment was conducted at the Grassland Science Experimental Station of Xinjiang Agricultural University on the northern slope of the Tianshan Mountains, Xinjiang, China. Eight treatments were established using a factorial design with two biochar rates (0 and 20 t·ha⁻¹; B0 and B20) and four N application rates (0, 75, 150, and 225 kg·ha⁻¹; N0, N75, N150, and N225). Results showed that biochar application significantly decreased soil bulk density and increased soil water content and electrical conductivity. It also elevated soil total carbon, total nitrogen, total phosphorus, NH₄⁺–N, and NO₃⁻–N concentrations, with B20N150 exhibiting the highest overall nutrient status. Plant community diversity indices did not differ significantly among treatments (p > 0.05), though B20 slightly enhanced Shannon–Wiener and Simpson indices under N0 and N75. Moderate N application significantly increased hay yield, whereas the highest N rate (225 kg·ha⁻¹) did not further improve yield and reduced NAUE. Biochar combined with N75 or N150 improved NAUE, and B20N150 achieved the best balance of high hay yield and high NAUE. Structural equation modeling revealed that soil water content (path coefficient = 0.45), NH₄⁺–N (0.27), and plant community diversity (0.20) were key positive drivers of NAUE, with biochar exerting indirect effects primarily via improving soil water and available N. Collectively, applying 20 t·ha⁻¹ biochar with 150 kg·ha⁻¹ N (B20N150) is recommended as an optimal strategy for N rate reduction and NAUE enhancement in artificial grasslands of arid and semiarid regions. Full article