Search Results (12,105)

The declining productivity, fertilizer inefficiencies, and rising energy cum production costs are the key issues in crop production, especially in semi-arid regions with alkaline soils. Integration of crop management strategies needs to be adopted to address these issues within the water–energy–food nexus (WEFN). For this purpose, a case study was conducted in semi-arid region of central Punjab, Pakistan, to evaluate the interactive effects of irrigation water source [canal water (CW) and tubewell water (TW)], phosphorus fertilizer source [diammonium phosphate (DAP) vs. phosphoric acid_25% (PA)], and fertilizer application levels [100% and 80% of recommended dose of fertilizer (RDF)] on maize productivity, energy efficiency and economic performance. The experiment comprises eight treatments under raised bed planting (RBP) and one control treatment under ridge-furrow sowing (RFS). Each treatment had three replicates, and the experiment was laid out under a randomized complete block design (RCBD). Maize growth, yield, water productivity, energy efficiency, and economic performance were analyzed using field measurements, energy equivalents, and partial budget analysis. The T1 (RBP+CW+PA+100%RDF) produced the highest maize yield, and it varied from 6.36 to 7.90 t ha⁻¹ under other treatments. CW significantly showed better water productivity (1.14–1.37 kg m⁻³) than that under TW (1.13–1.31 kg m⁻³); however, total energy input was higher under TW-based treatments (29,269–41,033 MJ t ha⁻¹) than that under CW-based treatments (24,129–29,681 MJ ha⁻¹). This results in lower energy productivity under TW-based treatments compared with CW-based treatments (0.17–0.23 kg MJ⁻¹ vs. 0.25–0.31 kg MJ⁻¹, respectively). Moreover, T2 (RBP+CW+PA+80%RDF) produced the highest energy use efficiency (0.59). Economic analysis revealed that production costs were nearly 15–17% higher under TW-based treatments, mainly due to the cost associated with groundwater pumping, and it reduced net profit to USD 1134–1385 ha⁻¹. Better net profits were achieved by CW-based treatments (USD 1244–1593 ha⁻¹), while those produced by BCR ranged from 3.11 to 3.69, with the highest value under T2 (RBP+CW+PA+80%RDF). Overall, irrigation water source emerged as the dominant driver of WEFN performance, while phosphoric acid significantly improved phosphorus availability, energy productivity, and economic returns, particularly under reduced fertilizer input. This study evidenced better maize productivity, less energy consumption, and improved farm profitability in semi-arid irrigated systems through the integration of canal water irrigation with optimized phosphorus management. Full article

Plant detritus plays a pivotal role in regulating soil nutrient dynamics within forest ecosystems. Understanding short-to-medium-term responses of soil-available nitrogen (AN) and phosphorus (AP) to altered detritus inputs is important for forest nutrient management. In this study, we investigated the effects of changing detritus inputs on soil AN and AP in two representative forest types in Northeast China—Korean pine (Pinus koraiensis Siebold et Zucc.) forest (KP) and Aspen (Populus ussuriensis Kom.)−birch (Betula platyphylla Sukaczev) forest (AB). Using the detritus input and removal treatments (DIRTs) method, we established six experimental treatments and measured soil ammonium nitrogen (NH₄⁺-N), soil nitrate nitrogen (NO₃⁻-N), and AP contents monthly from May to October. The results showed that significant differences in NH₄⁺-N, NO₃⁻-N, and AP contents were observed among treatments. Under the six DIRTs, the fluctuation ranges of NH₄⁺-N, NO₃⁻-N, and AP contents in KP soil were 1.16–12.52 mg/kg, 7.34–35.40 mg/kg, and 9.63–31.72 mg/kg, respectively. For AB soil, the fluctuation ranges of the above three nutrients under the six DIRTs were 2.94–13.17 mg/kg, 3.45–28.47 mg/kg, and 1.77–25.60 mg/kg, respectively. Root treatments exerted stronger effects on AN and AP than litter: root exclusion generally reduced NH₄⁺-N but increased NO₃⁻-N and AP, with the direction and magnitude of the response to this treatment varying with month and forest type, whereas litter treatments showed no consistent trends. The soil-available N:P ratio was lower in the KP forest than in the AB forest; root exclusion significantly reduced the N:P ratio in the AB forest but had no significant effect on that in the KP forest. In terms of seasonal dynamics, the study found that AN peaked in May and AP in July. In conclusion, these findings reflect the short-to-medium-term effects of plant detritus, forest type, and month on soil-available nitrogen and phosphorus, providing scientific insights into how detritus changes alter soil nutrients in temperate forests. Full article

Air and water pollution pose critical threats to public health and environmental stability, particularly in rapidly urbanizing developing nations. This study investigates synergistic interactions between air and water pollutants across 14 cities in Hunan Province, China (2020–2024), using multiparametric statistical approaches. The results show that the coefficient of variation (CV) of particulate matter (PM) with diameters less than 2.5 μm (PM_2.5, CV = 46.9%) and turbidity (TU, CV = 47.4%) showed the highest variability among the air and water quality parameters, respectively. Annual trends revealed significant increases in ozone (O₃) alongside decreases in carbon monoxide (CO) and nitrogen dioxide (NO₂) concentrations. Concurrently, freshwater systems exhibited rising electrical conductivity (EC), water temperature (WT), and pH, paired with declining levels of ammonia nitrogen (NH₃-N), total phosphorus (TP), and turbidity (TU). Principal component analysis (PCA) and Spearman correlation analyses showed significant positive correlations between PM and nitrogen species (TN, NH₃-N), but negative correlations with TP, suggesting potential cross-media pollution interactions. Cross-correlation analysis revealed significant time-lagged relationships (1–5 months) between atmospheric pollutants and aquatic nutrients, suggesting that atmospheric deposition may serve as a contributing pathway for cross-media contamination. The study not only provides empirical evidence for integrated pollution control strategies in urbanizing watersheds, but also offers a transferable framework for addressing similar air–water quality interactions on a global scale. Full article

To scientifically evaluate the health of river aquatic ecosystems in the Qianxinan Buyi and Miao Autonomous Prefecture, southwestern Guizhou, systematic surveys of benthic macroinvertebrate and periphytic algal communities were conducted in representative rivers during October 2024 (autumn) and April 2025 (spring), coupled with concurrent water quality monitoring. Reference sites were selected based on water quality indicators and habitat conditions. Core parameters were identified through correlation analysis, discriminatory ability analysis, and distribution range analysis to construct a Benthic Index of Biotic Integrity (B-IBI) and a Periphytic Algae Index of Biotic Integrity (P-IBI) suitable for the region. These indices were then applied to assess the ecological health of the rivers. Additionally, stepwise regression analysis was employed to investigate the key environmental drivers influencing the two biotic integrity indices. The results indicated that: (1) In terms of species composition, the benthic macroinvertebrate community structure was relatively simple, dominated by arthropods, particularly chironomid larvae. Bacillariophyta and Cyanophyta consistently dominated the periphytic algae community. (2) Assessments using both B-IBI and P-IBI showed that the overall river health in spring was slightly better than in autumn. However, more than half of the sampling sites were rated as “fair” or worse in both seasons. The reference sites (S2, S10) consistently exhibited “excellent” or “good” health, while the impaired sites showed significant spatial heterogeneity. Discrepancies between B-IBI and P-IBI ratings at some sites revealed differential responses of the two biological communities to environmental stressors. (3) Stepwise regression analysis unveiled a seasonal shift in key environmental drivers. The primary factor affecting the B-IBI in autumn was biochemical oxygen demand (BOD₅), which shifted to total phosphorus (TP) and ammonia nitrogen (NH₄⁺-N) in spring. For the P-IBI, the main factor changed from dissolved oxygen (DO) in autumn to chemical oxygen demand (COD) in spring. These findings confirm the applicability of the B-IBI and P-IBI systems in this region, and indicate that multi-assemblage integrated assessments can contribute to understanding the health status of river ecosystems in the Qianxinan Prefecture. This study could serve as a scientific reference for the protection, management, and restoration of local river ecosystems. Full article

As microplastic pollution intensifies, its impact on soil microbial communities has drawn widespread attention. This study treated soil samples with five microplastics, including polystyrene (PS), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), and polyethylene terephthalate (PET), to assess effects on soil properties. High-throughput sequencing was used to analyze soil fungal community structure and functional diversity. Results showed that microplastic treatments significantly altered pH, total carbon (TC), ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃⁻-N), and available phosphorus (AP). Notably, all treatments reduced NO₃⁻-N levels. Fungal community composition was affected, particularly Mortierellomycota and the genera Mortierella, Plectosphaerella, Pseudogymnoascus, Penicillium, Tuber, and Stachybotrys. Functional analysis revealed decreases in certain groups, especially Endophyte–Plant Saprotroph–Undefined Saprotroph and Endophyte–Plant Pathogen–Plant Saprotroph, in PE, PS, and PVC treatments. Mantel analysis further indicated that soil pH, NH₄⁺-N, and NO₃⁻-N significantly influenced fungal communities. These results highlight that microplastic pollution alters soil properties, thereby affecting fungal communities in a microplastic-type dependent manner, providing a theoretical basis for soil health management and pollution mitigation. Full article

The ecological restoration of degraded sandy land in the Yarlung Zangbo River Valley is constrained by the metabolic functions of soil microorganisms. This study investigates the dynamic mechanisms of microbial elemental use efficiency in walnut plantations, with a focus on seasonal variations in soil chemical stoichiometry, extracellular enzyme activity, and microbial nutrient efficiency in rhizosphere and bulk soils. This paper explores the effects of conventional organic fertilizer (CF) and organic–inorganic compound fertilizer (OIF) on microbial nutrient use strategies and their seasonal dynamics. The results showed significant seasonal fluctuations in soil active nutrients and microbial biomass, while the total nutrient content remained stable. OIF enhanced microbial chemical stoichiometric homeostasis but simultaneously triggered a “carbon–phosphorus metabolic trade-off”, leading to a restraint of microbial carbon use efficiency (CUE) during the growing season. Microbial elemental use efficiency (EUE) exhibited clear seasonal differentiation: CUE was higher in summer, promoting biomass accumulation, whereas NUE and PUE increased in winter and spring, reflecting a nutrient conservation strategy. The EUE pathways were decoupled between rhizosphere and non-rhizosphere microenvironments. The rhizosphere was more directly driven by soil chemical stoichiometry and microbial biomass, while the non-rhizosphere was influenced by nutrient limitation states, represented by vector characteristics. This study provides insights into the seasonal adaptability and microenvironmental heterogeneity of microbial metabolism during the restoration of cold sandy land. It is suggested that future ecological management should focus on N-P balanced fertilization and consider the differential responses between rhizosphere and non-rhizosphere zones to enhance ecosystem productivity and soil carbon, nitrogen, and phosphorus sequestration potential. Full article

This study systematically compared the structural, functional, pathogenic, and assembly-mechanism characteristics of bacterial communities between urban and rural rivers across China, based on integrated water quality data from 421 sampling sites and 16S rRNA gene sequences from 475 sampling sites. The results revealed that urban rivers had significantly higher nutrient concentrations and bacterial α-diversity, along with lower β-diversity. Urban rivers were enriched with organic matter-degrading phyla such as Chloroflexi and Acidobacteriota and might exhibit more complex co-occurrence networks (average degree: 85.41). In contrast, rural rivers were enriched with phyla including Firmicutes and Cyanobacteria, as well as genera such as Exiguobacterium and Limnohabitans, and might display higher network modularity (modularity: 0.59) and greater spatial heterogeneity in community composition. Functional prediction indicated stronger carbon-cycling potential in urban rivers, whereas nitrogen-cycling functions did not differ between the two river types. Regarding pathogen composition, urban rivers contained a higher number of pathogen species than rural rivers. It was suggested that stochastic processes dominated community assembly in both systems; however, heterogeneous selection contributed more strongly in urban rivers (14.7%). Overall, this work elucidated systematic differences in bacterial community structure, function, pathogen profile, and assembly mechanisms between urban and rural rivers, offering a scientific foundation for differentiated watershed management. Full article

Teeth may retain forensic value after chemical exposure, yet the effects of commercially available corrosive agents remain insufficiently characterized. This study evaluated short-term alteration patterns in human teeth exposed to household acidic and alkaline products available on the Romanian market. Five extracted mandibular third molars were analyzed, including four experimental teeth and one control. Each experimental tooth was fully immersed for 48 h in a different agent: hydrochloric acid descaler, sodium hypochlorite bleach, mixed hydrochloric/sulfuric acid descaler, or sodium hydroxide. Morphometric changes, mass, and pH were monitored serially, while stereomicroscopy, SEM-EDX, and hard tissue ground sections were used for structural and compositional assessment. Acid-exposed teeth showed the greatest damage, with major mass loss in the hydrochloric acid and mixed-acid samples, enamel loss, and marked microstructural disruption. The mixed-acid specimen exhibited the most severe collapse and near-complete calcium/phosphorus depletion. Sodium hypochlorite produced mainly superficial and root-level alterations with relative preservation of gross morphology, whereas sodium hydroxide caused minimal dimensional change and a calcium-rich adherent surface deposit. These findings show that household corrosives produce distinct, forensically recognizable dental alteration patterns within 48 h and support an integrated pattern-recognition approach in suspected chemical concealment scenarios. Full article

This study evaluates the oscillatory frequency and amplitude in an oscillatory flow reactor with smooth periodic constrictions (OFR-SPC) for the cultivation and harvesting of Chlorella vulgaris fed with an air stream with 5% (v/v) CO₂. Their effect on biomass productivity, CO₂ capture, nutrient removal, and sedimentation kinetics was assessed. Cultures were tested at frequencies of 0.5–2.5 Hz and amplitudes of 6–18 mm. At 2.5 Hz|6 mm, the system achieved the maximum biomass concentration (592 mg_DW L⁻¹), productivity (5.36 mg_DW L⁻¹ h⁻¹), and CO₂ fixation (8.34 mg L⁻¹ h⁻¹) as well as complete nitrogen removal and near-complete phosphorus removal (100% and 91%, respectively). Complete sedimentation occurred at 0.5 Hz|6 mm, with kinetics described by the Gompertz model (k = 4.60 h⁻¹), confirming the feasibility of low-cost biomass recovery. Additionally, zeta potential positively influenced sedimentation but negatively affected productivity. Statistical analyses confirmed oscillation frequency and amplitude as key factors, establishing the OFR-SPC as a promising technology for microalgae-based efficient CO₂ capture, nutrient removal, and low-cost biomass harvesting. Full article

Most major crops in agricultural soils exhibit relatively low nutrient use efficiency for nitrogen (N), phosphorus (P), and potassium (K), often necessitating supplemental nutrient inputs to achieve sustainable yields. Furthermore, the increasing use of biowastes such as compost, manure, and biosolids, which frequently have nutrient ratios that do not match crop requirements, has contributed to excessive nutrient inputs and subsequent accumulation in soils. This situation has been further exacerbated by intensive farming practices involving multiple cropping cycles per season. Overuse of nutrients causes them to accumulate in the soil, creating a legacy nutrient pool. The application of biochar as soil amendment is considered a potential strategy to control legacy nutrients dynamics. The current review inspects the possible value of biochar in modulating legacy nutrient reserves in the soil, thereby increasing the bioavailability of nutrients and improving crop yield. This review discusses the search scope and synthesis approaches for the bibliometric methodological component through rigorous screening process (Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA)), focusing on journal articles published in last 20 years that specifically address legacy nutrient management. The significance of the economic and environmental effects of legacy nutrients and the insufficient knowledge of how biochar application influences nutrient dynamics in soil highlight the necessity for additional research to address current gaps. Full article

Optimization of nutrient medium composition and cultivation conditions is a simple tool for directing enzyme biosynthesis of microbial strain towards the synthesis of a desired enzyme with maximum activity. The aim of the present study is to optimize the composition of the nutrient medium and the cultivation conditions for maximum phytase biosynthesis by Aspergillus tubingensis. The most suitable sources of carbon, inorganic and organic nitrogen, phosphorus and salts for obtaining maximum phytase activity were determined. The effect of concentration of medium components on phytase biosynthesis was investigated. The optimal component composition of the nutrient medium was determined to be rice starch, peptone and ammonium oxalate. A response surface methodology was applied for determination of the optimal concentrations of the components of the nutrient medium for maximum phytase biosynthesis. The optimal composition of the nutrient medium was determined to be rice starch 13.5 g/L, peptone 4.84 g/L and ammonium oxalate 2.92 g/L. With the optimized nutrient medium experimental value of 26.68 U/mL, phytase activity was obtained. This value was 185 % higher in comparison to the activity obtained with the initial nutrient medium (9.35 U/mL). By a simple optimization of the nutrient medium, a significant increase in phytase activity was achieved. Full article

The increasing use of silver nanoparticles (AgNPs) as nanoagrochemicals raises important environmental and toxicological considerations of their usage. AgNPs influence soil microbiome functioning, which regulates essential nutrient availability. However, their effects on key chemical soil health indicators remain unclear, with existing studies limited to concentrations ≥10-fold above predicted environmental levels. The aim of the work was to evaluate the effect of AgNPs at a realistic concentration of 10 μg/kg on the principal chemical soil health indicators, including acidity, redox potential, electrical conductivity, contents of NPK, and soil organic carbon (SOC). In addition, dissolved organic carbon and nitrogen (DOC and DON) and water-extractable elements (Al, Ca, Fe, K, Mg, Na, P, S, and Si) were also examined. The laboratory experiment was carried out for 3 months on Retisol, Chernozem, and Solonetz. AgNPs stabilised with carboxymethylcellulose (AgNP-CMC) or polyvinylpyrrolidone (AgNP-PVP) were used. AgNP-induced changes exhibited non-monotonic patterns, peaking at 2–3 months of incubation. A statistically significant effect observed across all soils following AgNPs application included only increased water-extractable Fe. In addition, AgNPs increased nitrate content 1.1–1.4-fold in Retisol and Chernozem, while available phosphorus increased 1.4-fold in Solonetz. However, changes were transient, indicating no pronounced long-term impact on soil properties. Partial Least Square (PLS) analysis revealed that chemical soil health indicators and water-extractable elements do not reliably discriminate between control soils and soils amended with AgNPs. Although our study shows that AgNPs had neither markedly negative nor positive effects on chemical soil health indicators or water-extractable element contents, future research should prioritise field trials. Model experiments under optimised microbial activity conditions limit direct extrapolation to field scenarios. Full article

Rhodium is a high-value strategic platinum-group metal extensively applied in automotive exhaust purification, fine chemicals, glass production and high-temperature materials. Restricted by uneven primary resource distribution and volatile market prices, recovering rhodium from secondary resources has become increasingly critical. Solvent extraction is regarded as a promising technology for continuous and selective separation of rhodium, yet direct extraction of Rh(III) from chloride media faces severe industrial limitations. These bottlenecks are mainly attributed to diversified chloro-aqua complexes, kinetic inertness of low-spin Rh(III), strong hydration capacity and polynuclear species generation, while solution aging and inconsistent thermodynamic-experimental results further complicate extraction behaviors. This review systematically summarizes recent advances in rhodium solvent extraction from chloride media, correlating aqueous speciation regulation, activation chemistry, extractant molecular structure and extraction-stripping mechanisms. Special emphasis is placed on SnCl₂-, ascorbic acid-, trichloroacetic acid- and malonate-assisted activation systems, as well as amine-, phosphorus-, sulfur-based, synergistic, ionic-liquid and deep-eutectic-solvent extractants. Key factors affecting extraction efficiency, distribution ratio, selectivity and stripping performance are clarified, and current challenges are outlined. Future research should focus on quantitative speciation analysis, in situ mechanistic characterization, targeted extractant design, and integrated evaluation of extraction, stripping, recyclability, cost and real-feed adaptability, so as to provide theoretical support for efficient and clean rhodium recovery. Full article

Understanding how soil arthropod communities respond to nutrient enrichment is important for assessing grassland ecosystem health, but such knowledge remains limited for degraded Sophora alopecuroides grasslands. To address this gap, a two-year field experiment was conducted in the Tuhulusu grassland (Xinjiang, China) with four treatments: nitrogen (N) addition, phosphorus (P) addition, combined N and P (NP) addition, and an unamended control (CK). Soil arthropod communities and environmental variables were monitored during the flowering, maturity, and senescence stages of S. alopecuroides. Across all treatments, three taxa—Oppiidae, Hypoaspidae, and Rhagidiidae—remained dominant, indicating wide ecological tolerance. Nutrient addition significantly altered arthropod individual density (response variable) and soil properties, including total phosphorus, available phosphorus, nitrate−N, ammonium−N, and pH (all p < 0.001), and these effects were strongly linked to plant phenology. The dominance, evenness, and Shannon diversity indices ranked as NP > CK > P > N. The key environmental drivers varied by treatment: total phosphorus and soil moisture under N addition, soil moisture under P and NP addition, and pH and electrical conductivity under CK. Collectively, these findings provide evidence that soil arthropod communities in S. alopecuroides grasslands are sensitive to nutrient enrichment in a phenology−dependent manner, with soil moisture content emerging as a critical limiting factor under nutrient−added conditions. Full article

Soil microbes play pivotal roles in nutrient cycling and ecosystem functioning across diverse farmland systems. Orchard grass coverage has been demonstrated to effectively alter microbial community structure and promote nutrient cycling. However, the effects of soybean intercropping on soil bacterial community characteristics and nutrient contents in citrus orchards remain poorly understood. In this study, a field experiment was conducted in a citrus orchard involving three planting patterns: clean tillage (CT), natural grass (NG), and soybean intercropping (SI). The physicochemical properties and bacterial community structure of the topsoil (0–40 cm depth) were determined. Results showed that compared with CT, NG and SI significantly increased cation exchange capacity (CEC), soil organic matter (SOM), alkali-hydrolyzable nitrogen (AN), and available potassium (AK). SI further elevated soil pH and available phosphorus (AP) relative to CT and NG. Bacterial diversity ranked SI > NG > CT, with PCoA showing lower community variation under SI. A total of 31 bacterial phyla were detected in the citrus orchard soil, with Cyanobacteria (17.20~40.81%), Proteobacteria (15.04~24.19%), Acidobacteriota (8.95~14.66%), and Chloroflexi (3.93~21.13%) identified as the dominant phyla. SI enriched Cyanobacteria and Proteobacteria but reduced Acidobacteriota, Chloroflexi, and Actinobacteriota. Mantel tests confirmed CEC and SOM as key drivers of bacterial community structure. Overall, soybean intercropping improves soil microecology and exhibits great potential for soil quality improvement in citrus orchards under local conditions. Full article