TP Content Research Articles

Influence of solid residence time on the phosphorus adsorption of extracellular polymer substances

Influence of solid residence time (SRT) on phosphorus (P) adsorption of extracellular polymer substances (EPS) was investigated from the perspectives of the contents, compositions and properties of loosely bound and tightly bound extracellular polymers (i.e., LB-EPS and TB-EPS) and microbial community structure. The TP contents of EPS were 59.6±6.0 - 87.4±4.4 mg·g-1 VSS and 63.7% - 68.1% of those of sludge, which was still underestimated due to the residual TB-EPS protecting cell membrane integrity. The influences of SRT on the yield and compositions of TB-EPS were obviously greater than those of LB-EPS. Compared with the SRTs of 12 d and 18 d, the significant P storage enhancement of biological P removal (BPR) sludge with the SRT of 25 d was related with the increases of TB-EPS yield, polyP content and average chain length in TB-EPS. The P adsorption property of TB-EPS was slightly increased through increasing SRT, while the K, Mg and Ca adsorption properties were markedly reduced. Increasing extracellular P content could kept good BPR efficiency at longer SRTs, but the loss risk of phosphorus accumulating organism dominance was increased. Additionally, adding Mg and Ca salts might improve extracellular P adsorption at longer SRTs.

An integrative metabolomics and metagenomics analysis of functional microbiota examines the extraction of bioactive products using longan pericarp

Longan (Dimocarpus longan Lour.) is a nutrient-rich fruit, widely cultivated in China. However, its seeds and pericarp, often discarded as waste, are rich in bioactive components, particularly polyphenolics. In this research, we develop microbiota-assisted extraction technique, which is efficient and environmentally friendly for extracting these valuable components. These results showcased superior efficiency in the diversity and richness of extracted bioactive components, although yielding slightly lower TP content than ethanol extraction. The active components extracted by microbiota-assisted extraction technique increased to 2.45 mg/g, which was higher 2.13 times and 3.10 times compared to optimized ethanol and water extraction, respectively. The numbers of active components extracted by these three methods were 39, 24 and 30, separately, and Quercetin 3-D-xyloside and Kaempferol 3-O-alpha-L-rhamnopyranosyl were identified in longan pericarp extracts by microbiota-assisted extraction. Metagenomics analysis revealed stable and diverse microbiota with functional capabilities for enhancing extraction efficiency. Functional annotations indicated significant roles in biosynthesis, carbohydrate degradation, and fatty acid metabolism. Microbiota-assisted extracts exhibited a broad spectrum of bioactive compounds with potential health benefits, including antioxidant and anti-inflammatory properties. These results provide a theoretical foundation for developing sustainable extraction technologies.

Characteristics of inter-root soil bacterial community structure and diversity of different sand-fixing shrubs at the southeastern edge of the Mu Us Desert, China

PurposeThis study aimed to investigate the effects of different shrub plants on the structure and diversity of inter-root soil bacterial communities, in order to provide scientific support for ecological restoration and revegetation of the Mu Us Desert.MethodsThree major shrub plants (Artemisia ordosica, Salix psammophila, Caragana microphylla) in the Mu Us Desert were selected for this study. Using high-throughput sequencing technology, the bacterial community structure and diversity in the inter-root soils of these plants were analysed in depth, and combined with the determination of soil physicochemical and microbiological properties, the response characteristics of the bacterial diversity in the inter-root soils of the different plants were assessed comprehensively.ResultsIt was found that although the soil pH did not show significant differences among different plant growths, the SOC, TN and TP contents were higher in Salix psammophila sample plot and Artemisia ordosica sample plot, which indicated that the plant growths had a positive effect on the soil nutrient contents. Through Venn diagram analysis, it was observed that the number of OTUs of bacteria in the soils of different shrubland sites varied, and all of them were higher than those in the soils of the sample sites where no plants grew, which indicated that plants had an effect on soil bacterial diversity. The bacterial Chao1 index were higher in the Artemisia ordosica sample plot sample site, suggesting that the growth of Artemisia ordosica contributes to the enhancement of soil bacterial richness. Soil bacterial communities showed compositional differences among different sample plots, especially the higher relative abundance of Betaproteobacteria in the Artemisia ordosica sample plot sample plot, which may be related to the increase of soil organic matter content.ConclusionThe results of the study revealed that specific plants, such as Artemisia ordosica, can significantly improve the soil nutrient status of windy sandy soils, increase soil organic matter and nitrogen content, and thus enhance the diversity and abundance of soil microorganisms. The bacterial community structure in the inter-root soils of different plants differed significantly, with changes in the relative abundance of the dominant phyla, such as Alphaproteobacteria, Betaproteobacteria and Actinobacteria, reflecting the differences in soil nutrient status. These findings emphasise the important role of plants on soil chemical properties and microbial community structure, providing an important basis for soil management and ecological restoration.

Experimental Study on the Effects of Tapioca Starch on Cement Mortar Quality Improvement.

In this study, the effect of tapioca starch (TP) on mortar was evaluated by incorporating TP into the mortar mixture. The evaluation involved analyzing the mortar's quality characteristics, performance, and fundamental quality improvements. The addition of TP resulted in a decrease in flow, which was attributed to increased viscosity. Specifically, a 10% reduction in flow was observed with a 0.025% increase in TP content. After 28 days, the impact of TP on the compressive strength of the mortar remained consistent, regardless of the TP amount. However, within the first 3 days, higher TP content accelerated strength development, with early compressive strength increasing by up to 20% at a 0.050% TP level. Additionally, bond strength improved by approximately 60% at a 0.050% TP concentration, and final shrinkage was reduced by 5%.

Removal of Hg(II) with MgAl-layered double hydroxide functionalized by schiff base ligands: Application and condition optimization

To effectively remove heavy metal Hg(II) from water bodies, a novel adsorbent of MgAl-layered double hydroxide (LDH) was designed and functionalized with Schiff base. The characterization results of the adsorbent (MgAl-LDH@SiO2-AG) show that the Schiff base polymer was successfully coated onto the outside surface of MgAl-LDH with hexagonal structure. The theoretical maximum adsorption capacity to Hg(II) is 228.46 mg/g at pH 7 and 298 K. The different pH solutions were investigated from pH 2 to 8, and the optimal capacity of MgAl-LDH@SiO2-AG toward Hg(II) achieves 268.7 mg/g at pH = 7.2, T = 36.8 °C, C0 = 32.1 mg/L and dosage = 0.083 g/L. In reality, the adsorbent not only exhibits efficient removal of Hg(II) in various water bodies, including lake water, river water, effluent from sewage treatment plant, but also has an excellent selectivity in electroplating wastewater containing different heavy metal ions. Low contents of TN and TP in real wastewater have less effect on the removal of Hg(II). Moreover, the prepared adsorbent had a good reusability and stability. The reaction mechanism mainly involves chelation with nitrogen/oxygen-containing groups and the predominant participation of nitrogen atoms in the Schiff base functional group. The removal of Hg(II) relies on the pseudo-second-order kinetics and Langmuir model, and is an endothermic and spontaneous chemical reaction. The present work offers a practical method for preparing highly effective adsorptive materials with the LDH composites and for the treatment of heavy metal Hg(II) from water bodies.

Dietary curcumin supplementation attenuates hepatic damage and function abnormality in a chronic corticosterone-induced stress model in broilers

Chronic stress refers to the activation of the hypothalamic-pituitary-adrenal (HPA) axis and elevated blood contents of ACTH and corticosterone (CORT), exhibiting significant adverse effects on health outcomes. Currently, natural polyphenol compounds are increasingly being explored as potential therapeutic agents and have been considered as a treatment option for a variety of stress-induced diseases. Curcumin (CUR) is the main substance in Curcuma longa (Zingiberacea) rhizome that has strong health-beneficial properties. The study aimed to assess the potential protective effects of CUR on hepatic oxidative stress damage and abnormal lipid deposition in a chronic CORT-induced stress (CCIS) model in broilers. One hundred and twenty experimental broilers were randomly divided into 1) control group (CON), 2) CUR group (200 mg/kg feed), 3) CORT group (4 mg/kg BW CORT) and 4) CORT+CUR group (200 mg/kg feed plus 4 mg/kg BW CORT). The liver histology, glycolipid metabolism and oxidative stress were determined. In addition, qPCR was performed to identify shifts in genes expression. Compared with CON group, broilers under CCIS showed a decreased body weight, body weight gain and average daily gain, while dietary CUR significantly reversed these adverse effects. Furthermore, the plasma contents of TCH, TG, HDL-C, LDL-C, TP, GLB and AST were all significantly increased in CCIS broilers, while dietary CUR obviously alleviated the increase of TCH, HDL-C, LDL-C and AST, and relieved the hepatic lipid deposition disorder and liver injury. Moreover, CCIS significantly increased the contents of MDA in both liver and plasma, and decreased the content of plasma SOD, while CUR obviously reversed these changes, showing reduced oxidative stress damage. Finally, the mRNA expressions of FAS, ACC, SCD and the protein level of PPAR-γ were significantly increased, meanwhile the mRNA expression of lipolytic genes ACOX1, ATGL and CPT as well as two major intracellular antioxidant enzymes SOD1 and GPX1 were obviously decreased, while CUR effectively reversed these effects. These results showed that dietary CUR effectively alleviated CCIS-induced body weight loss, hepatic oxidative damage and lipid deposition disorder, suggesting the possible therapeutic effectiveness of CUR against hepatic damage and function abnormality caused by CCIS.

Integration of physiological, miRNA-mRNA interaction and functional analysis reveals the molecular mechanism underlying hypoxia stress tolerance in crucian carp (Carassius auratus).

Hypoxia has become one of the most critical factors limiting the development of aquaculture. Crucian carp (Carassius auratus) is widely consumed fish in China, with excellent tolerance to hypoxic environment. However, the molecular mechanisms underlying hypoxia adaptation and tolerance in crucian carp remain unclear. Compared with the control, increased T-SOD, CAT, GSH-Px, T-AOC, ALT, and AST activities and MDA, TCHO, and TG contents, and decreased TP and ATP contents were observed after hypoxia stress. Based on RNA-seq, 2479 differentially expressed (DE) mRNAs and 60 DE miRNAs were identified, and numerous DE mRNAs involved in HIF signaling pathway (hif-1α, epo, vegfa, and ho), anaerobic metabolism (hk1/hk2, pfk, gapdh, pk, and ldh) and immune response (nlrp12, cxcr1, cxcr4, ccr9, and cxcl12) were significantly upregulated after hypoxia exposure. Integrated analysis found that ho, igfbp1, hsp70, and hk2 were predicted to be regulated by novel_867, dre-miR-125c-3p/novel_173, dre-miR-181b-5p, and dre-miR-338-5p/dre-miR-17a-3p, respectively, and targets of DE miRNAs were significantly enriched in MAPK signaling pathway, FoxO signaling pathway, and glycolysis/gluconeogenesis. Expression analysis showed that the mRNA levels of vegfa, epo, ho, hsp70, hsp90aa.1, igfbp1, ldh, hk1, pfk, pk, and gapdh exhibited a remarkable increase, whereas sdh and mdh were downregulated in the H3h, H12h, and H24h groups compared with the control. Furthermore, research found that hk2 is a target of dre-miR-17a-3p, overexpression of dre-miR-17a-3p significantly decreased the expression level of hk2, while the opposite results were obtained after dre-miR-17a-3p silencing. These results contribute to our understanding of the molecular mechanisms of hypoxia tolerance in crucian carp.

Root growth characteristics and antioxidant system of Suaeda salsa in response to the short-term nitrogen and phosphorus addition in the Yellow River Delta.

Human activities have increased nitrogen (N) and phosphorus (P) inputs to the Yellow River Delta and the supply level of N and P affects plant growth as well as ecosystem structure and function directly. However, the root growth, stoichiometry, and antioxidant system of plants in response to N and P additions, especially for herbaceous halophyte in the Yellow River Delta (YRD), remain unknown. A field experiment with N addition (0, 5, 15, and 45 g N m-2 yr-1, respectively) as the main plot, and P addition (0 and 1 g N m-2 yr-1, respectively) as the subplot, was carried out with a split-plot design to investigate the effects on the root morphology, stoichiometry, and antioxidant system of Suaeda salsa. The results showed that N addition significantly increased the above-ground and root biomass as well as shoot-root ratio of S. salsa, which had a significant interaction with P addition. The highest biomass was found in the treatment with 45 g N m-2 yr-1 combined with P addition. N addition significantly increased TN content and decreased C:N ratio of root, while P addition significantly increased TP content and decreased C:P ratio. The main root length (MRL), total root length (TRL), specific root length (SRL), and root tissue density (RTD) of S. salsa root were significantly affected by N addition and P addition, as well as their interaction. The treatments with or without P addition at the 45 g N m-2 yr-1 of N addition significantly increased the superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) activities and soluble protein content of roots, decreased malondialdehyde (MDA) content. And there was a significant interaction between the N and P addition on SOD activity. Therefore, N and P additions could improve the growth of S. salsa by altering the root morphology, increasing the root nutrient content, and stimulating antioxidant system.

Profiling sediment bacterial communities and the response to pattern-driven variations of total nitrogen and phosphorus in long-term polyculture ponds

Sediment bacterial communities are decisive drivers of nutrient cycling processes in aquaculture ecosystems and are readily affected by surrounding environmental factors. However, the knowledge of sediment nutrient accumulations and bacterial community structure is limited in the emerging polyculture systems. Herein, we investigated the profiles of sediment properties and bacterial communities in six typical polyculture ponds and primarily explored the influence of total nitrogen and phosphorus on the bacterial species and diversity. In almost all sediment samples, Proteobacteria, Chloroflexi, and Bacteroides were the dominant species at the phylum level, and the five most abundant bacterial genera were Sulfurovum, Woeseia, Ilumatobacter, Robiginitalea, and Cyanobium_PCC-6307. A clear different bacterial community was observed with the most dominant bacterial phylum Firmicutes and the lowest bacterial diversity in TZ1 pond sediment; meanwhile, the TZ1 pond also showed the highest TN and TP concentrations. Notably, sediments from WZ1 and WZ2 ponds in low-latitude regions exhibited higher bacterial richness and diversity. Based on Pearson’s correlation analysis, bacterial α-diversity indices showed significant negative correlation with sediment TP content, and TN content contributed the most to the abundance of sediment dominant bacterial genus, indicating that the bacterial community is highly associated with sediment nutrient concentrations. Moreover, co-occurrence network analysis further revealed some keystone taxa that exhibited high correlations with other bacterial species, especially the high-abundance genus Robiginitalea bridging a large number of connections. Compared to traditional mono-mariculture pattern, our study provided direct evidence of lower nutrient loadings and different bacterial communities in the polyculture ponds. This could assist polyculture practitioners in developing effective strategies for detailed nutritional management.

Fractionation of Inorganic Phosphorus in Cold Temperate Forest Soils: Associating Mechanisms of Soil Aggregate Protection and Recovery Periods after Forest Fire Disturbance

The soil aggregate is the fundamental unit of soil structure. The fractionation characteristics and influencing factors of phosphorus (P) in soil aggregates inherently link its geochemical characteristics and recycling mechanism. This work investigated the fractionation characteristics of inorganic P in cold temperate forest soils and studied the impacts of recovery periods after forest fires and soil aggregate protection mechanisms on P fractionation. Our results showed that the TP, active P, stable P, and total organic carbon (TOC) contents varied with increasing recovery years after forest fire disturbance. The TP content in the coarse particulate organic matter fraction (cPOM) exhibited an increasing trend with the number of recovery years. Redundancy analysis (RDA) and correlation analysis indicated that TOC played a crucial role in influencing the dynamics of P fractionation during the recovery process. The order of TP levels in different soil aggregate fractions was as follows: μClay > dClay > LF > cPOM > dSilt > μSilt > iPOM, with significant contributions from the cPOM and dSilt fractions. The ranking of P fractions in bulk soils was as follows: ACa-P > Fe-P > Oc-P > Or-P > De-P > Al-P > Ex-P. The protective mechanism of soil aggregates had a more significant effect on TOC than TP, with the order of protective abilities being: Phy×biochem-protected > Biochem-protected > Phy-protected > Non-protected mechanism. TOC and recovery years emerged as critical factors influencing the dynamics of different P fractions during post-fire recovery. Soil aggregate protection mechanisms demonstrated significantly higher effects on TOC than on TP. This study provides insights into the fractionation mechanisms of P in the soil–forest ecosystem of the Greater Khingan Mountains, contributing to the sustainable development and utilization of cold temperate forest ecosystems.

Oilseed Radish: Nitrogen and Sulfur Management Strategies for Seed Yield and Quality—A Case Study in Poland

Oilseed Radish: Nitrogen and Sulfur Management Strategies for Seed Yield and Quality—A Case Study in Poland

Unlocking the potential of sorghum: a comparative study exploring the physical, chemical, technological, and digestibility properties of new cultivars from Mozambique

SummaryThis study aimed to evaluate the physical, chemical, technological, and digestibility of three sorghum cultivars (Mucuvea, Otela, and Tocole) and compared them to a Local variety (criola) grown in Mozambique. Thousand‐grain weight, hectolitre weight, and colour were determined in the grains. Proximal composition, antinutritional factors, starch and protein digestibility, and antioxidant activity were analysed in flours; starch was isolated and characterised by its physical, chemical, morphological, and digestibility properties. The grain characterisation varied among the cultivars compared to the Local variety, but not between the cultivars. The cultivars showed lower amounts of protein, lipids, free phenolics, tannin, soluble protein, digestibility of starch flour and proteins, and higher flavonoids and antioxidant activity. A high content of amylose (~37%), glycaemic index (~82), Tp (64.83 °C), and resistant starch (57.73%) were verified in all cultivars. The peak viscosity of Local variety was higher (343.25 RVU) than the other cultivars, while the breakdown (less than 106.54 RVU) of the cultivars was significantly lower than Local (182.25 RVU). Such data suggest great potential use of Local variety in bakery products and the cultivars in products that require greater viscosity. These results will reinforce the research, production, and manufacture of new products in Africa, especially in sorghum‐producing countries.

Differential response patterns of soil fungal and bacterial communities to typical vegetation types in the Yellow River floodplain ecosystem

Soil microorganisms are one of the primary driving factors of biogeochemical cycles in floodplain ecosystems. Vegetation type has an impact on the activities of soil microorganisms. However, it is currently unclear whether the composition and structure of soil bacterial and fungal communities in floodplain ecosystems have a consistent response pattern to vegetation communities. In this research, Illumina Mi-Seq sequencing technology was employed to study the soil fungal and bacterial communities covered by three typical vegetation communities in the Yellow River floodplain ecosystem. Our results showed that the underground biomass, total carbon (TC) and nitrogen (TN) were significantly different between the three vegetation communities. In the surface soil of summer, the Shannon index of fungi community was the highest in Tamarix chinensis (T. chinensis) and the lowest in Phragmites australis (P.australis). In autumn, the Shannon and Simpson indices of bacterial communities in surface soil were the highest in the P.australis and the lowest in the Sonchus arvensis (S.arvensis), but there was no significant difference in the β-diversity of bacterial community among the three vegetation communities. In autumn, the Chao1 index of fungal community in subsoil was the highest in P.australis and the lowest in S.arvensis, while there was no significant difference in the α-diversity of bacterial community among the three vegetation communities. In addition, there were considerable disparities in the fungal and bacteria community structure in various vegetation soils. Redundancy analysis (RDA analysis) showed that TN, TC, AP, pH, NO3 -, NH4 + and moisture content were key factors driving bacterial community structure, while TP, NH4 +, pH and moisture content were essential factors driving fungal community composition. These outcomes help to improve our understanding of the ecological model of soil fungal and bacterial community in floodplain ecosystems and give assistance in improving the role of an ecological barrier and floodplain service possibilities.

Nutrient enrichment decreased the Cross-Taxon congruence across bacteria, fungi, and zoobenthos in sediment

Eutrophication is a major problem currently affecting sediment biodiversity in different kingdoms. Surveys at different spatial scales have suggested that nutrient enrichment drove the congruence in biodiversity across different kingdoms. In this study, we examined the diversity indexes of bacteria, fungi, and zoobenthos in Dongting Lake, which is undergoing different trophic levels. The species richness and Shannon index of bacteria, fungi, and zoobenthos were all consistent with the intermediate disturbance hypothesis along the content of TN and TP, with the hysteresis of fungal group. Significant cross-taxon congruence was found in species richness between bacteria and zoobenthos, and Shannon index between bacteria and fungi. Also, the strength of congruence in biodiversity among bacteria, fungi and zoobenthos would decrease along nutrient enrichment. Multi- and single-kingdom networks found that bacterial group contained more nodes and edges compared to fungal and zoobenthos groups, and bacterial removal led to the lowest natural connectivity. And highest positive interaction proportion and lowest absolute value of natural connectivity slope were observed in zoobenthos group. These results highlighted the importance of bacteria as stabilizer in sediment ecosystem, and the most sensitive feature of zoobenthos to nutrient enrichment. Taken together, our results confirmed the cross-taxon congruence between multi-kingdoms, and the effectiveness of bacteria as a potential bioindicator of ecological change.

Responses of Crop Yield, Soil Fertility, and Heavy Metals to Spent Mushroom Residues Application.

Waste mushroom residues are often returned to fields as organic amendments. Here, we estimated the effects of the continuous applications of different spent mushroom substrates for 2 years on crop yields, soil nutrients, and heavy metals in paddy fields. The study comprised seven treatments: no fertilization (CK) and mineral NPK fertilizer (CF), as well as NPK fertilizer combined with Enoki mushroom residue (EMR50), Oyster mushroom residue (OMR50), Auricularia polytricha mushroom residue (APR50), Shiitake mushroom residue (SMR50), and Agaricus bisporus residue (ABR50). The grain yield was highest under the APR50 treatment. The short-term application of waste mushroom residue significantly increased SOC, TN, TP, and TK content relative to the CK treatment. The SOC, TP, and TK were highest under ABR50. Both total Cr and Cd contents were highest under CF treatment. The highest cumulative ecological risk was observed under OMR50 treatment. In addition, crop yield was positively correlated with SOC, TN, TP, and TP. Our results highlight that further research and innovation are needed to optimize the benefits and overcome the challenges of mushroom residue application.

Liver and mucous secretion enzymatic biomarkers of Eobania vermiculata treated with some newly synthesized acrylamide derivatives

Abstract Background Acrylamide derivatives have a potential biological activity as well as acting as precursors in many organic syntheses. Moreover, acrylamides and their derivatives cause convulsions and diffused damage to different sections of the nervous system of infected animals. Novel copper and zinc chelates originated from (E)-3-(4-bromophenyl)-2-cyanoacrylamide (L1), and (E)-2-cyano-3-(4-nitrophenyl)acrylamide (L2) were prepared, and their chemical skeletons were identified by infrared and mass spectra. The obtained compounds were screened in vitro against the brown garden snail, Eobania vermiculata using the contact method along 72 h. Stock solutions of tested compounds were prepared utilizing distilled water and DMSO mixture, and four concentrations of each compound were prepared (50, 150, 250 and 350 ppm). Eobania vermiculata snails were treated with LC50 concentrations of prepared compounds for 3 days, and live snails were used to estimate the level of some liver and mucous secretion enzymatic biomarkers: transaminases enzymes (Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST)), Total Protein content (TP), Acid Phosphatases (ACP) and Alkaline Phosphatase (ALP). Results The results demonstrated that the examined compounds have a relatively toxic effect toward the screened species. Zinc complexes displayed a higher toxicity than copper ones. The results authenticated considerable high effects of the synthesized compounds on investigated enzymes. Conclusions The promising effects of Cu(II), Zn(II) complexes (1, 2) on stimulating the mucous secretion of tested snails are clear through the elevated levels of ALP and ACP enzymes of treated snails. The enhancement or reduction of AST, ALT level and TP content of treated snails demonstrated the effects of prepared compounds on liver functions of these species.

Effects of Straw Returning and New Fertilizer Substitution on Rice Growth, Yield, and Soil Properties in the Chaohu Lake Region of China

Recently, replacing chemical fertilizers with straw returning and new fertilizers has received considerable attention in the agricultural sector, as it is believed to increase rice yield and improve soil properties. However, less is known about rice growth and soil properties in paddy fields with the addition of different fertilizers. Thus, in this paper, we investigated the effects of different fertilizer treatments, including no fertilization (CK), optimized fertilization based on the medium yield recommended fertilizer amount (OF), 4.50 Mg ha−1 straw returning with chemical fertilizers (SF), 0.59 Mg ha−1 slow-release fertilizer with chemical fertilizers (SRF), and 0.60 Mg ha−1 water-soluble fertilizer with chemical fertilizers (WSF), on rice growth, yield, and soil properties through a field experiment. The results show that compared with the OF treatment, the new SF, SRF, and WSF treatments increased plant height, main root length, tiller number, leaf area index, chlorophyll content, and aboveground dry weight. The SF, SRF, and WSF treatments improved rice grain yield by 30.65–32.51% and 0.24–1.66% compared to the CK and OF treatments, respectively. The SRF treatment increased nitrogen (N) and phosphorus (P) uptake by 18.78% and 28.68%, the harvest indexes of N and P by 1.75% and 0.59%, and the partial productivity of N and P by 2.64% and 2.63%, respectively, compared with the OF treatment. However, fertilization did not significantly affect the average yield, harvest indexes of N and P, and partial productivity of N and P. The contents of TN, AN, SOM, TP, AP, and AK across all the treatments decreased significantly with increasing soil depth, while soil pH increased with soil depth. The SF treatment could more effectively increase soil pH and NH4+-N content compared to the SRF and WSF treatments, while the SRF treatment could greatly enhance other soil nutrients and enzyme activities compared to the SF and WSF treatments. A correlation analysis showed that rice yield was significantly positively associated with tiller number, leaf area index, chlorophyll, soil NO3−-N, NH4+-N, SOM, TP, AK, and soil enzyme activity. The experimental results indicate that SRF was the best fertilization method to improve rice growth and yield and enhance soil properties, followed by the SF, WSF, and OF treatments. Hence, the results provide useful information for better fertilization management in the Chaohu Lake region of China.

Water environmental capacity analysis and eutrophication assessment of water-supplied reservoirs

The protection of water quality in reservoirs, particularly those designated for water supply, has garnered increasing attention for environmental management purposes. In this paper, the Shuangxikou Reservoir in Yuyao was chosen as a case study. The pollutant load at various points within the reservoir was analyzed and its eutrophication level was evaluated through a combination of site surveys and regular monitoring. Additionally, a model trial algorithm was utilized to investigate the water environment capacity concerning key pollutant indicators such as COD, NH3-N, TN, and TP in Shuangxikou Reservoir. The results indicated that the nutrient level in Shuangxikou Reservoir fell within the mid-trophic range, with water quality being superior in the central region compared to other areas. However, when compared to the water quality target of Class II surface water mandated by water environment functional zoning, the current TN and TP content in the reservoir exceeds acceptable levels. Consequently, targeted measures are imperative to enhance water quality in the reservoir.

Phosphate solubilization and plant growth properties are promoted by a lactic acid bacterium in calcareous soil.

On the basis of good phosphate solubilization ability of a lactic acid bacteria (LAB) strain Limosilactobacillus sp. LF-17, bacterial agent was prepared and applied to calcareous soil to solubilize phosphate and promote the growth of maize seedlings in this study. A pot experiment showed that the plant growth indicators, phosphorus content, and related enzyme activity of the maize rhizospheric soils in the LF treatment (treated with LAB) were the highest compared with those of the JP treatment (treated with phosphate solubilizing bacteria, PSB) and the blank control (CK). The types of organic acids in maize rhizospheric soil were determined through LC-MS, and 12 acids were detected in all the treatments. The abundant microbes belonged to the genera of Lysobacter, Massilia, Methylbacillus, Brevundimonas, and Limosilactobacillus, and they were beneficial to dissolving phosphate or secreting growth-promoting phytohormones, which were obviously higher in the LF and JP treatments than in CK as analyzed by high-throughput metagenomic sequencing methods. In addition, the abundance values of several enzymes, Kyoto Encyclopedia of Genes and Genomes (KEGG) orthology, and Carbohydrate-Active Enzymes (CAZys), which were related to substrate assimilation and metabolism, were the highest in the LF treatment. Therefore, aside from phosphate-solubilizing microorganisms, LAB can be used as environmentally friendly crop growth promoters in agriculture and provide another viable option for microbial fertilizers. KEY POINTS: • The inoculation of LAB strain effectively promoted the growth and chlorophyll synthesis of maize seedlings. • The inoculation of LAB strain significantly increased the TP content of maize seedlings and the AP concentration of the rhizosphere soil. • The inoculation of LAB strain increased the abundances of the dominant beneficial functional microbes in the rhizosphere soil.

Enzymatic Stress Responses of Coreius guichenoti to Microplastics with Different Particle Sizes.

The wild population resources of Coreius guichenoti have sharply declined in recent decades, and any negative factors may have a significant impact on their survival. In this study, the enzymatic stress responses of C. guichenoti to 25 and 48 μm polyethylene fragments were explored for the first time. This was achieved by evaluating the changes in physiological and biochemical indicators of the species in response to the environmental stimuli of microplastics. In this study, we observed an early stress response in the external tissues of C. guichenoti following exposure to microplastics. The TP content in skin and muscle and the MDA content in skin, gill and muscle initially showed a significant increase. The skin, gill, and muscle exhibited greater stress responses to M5 particles, whereas M3 particles caused a greater response in the intestine and especially the liver. After the removal of microplastic exposure, the stress state of the C. guichenoti would be alleviated in a short period, but it could not fully recover to the pre-exposure level. In summary, microplastics pose a significant threat to C. guichenoti. While their negative effects can be alleviated by the removal of microplastics exposure, full recovery does not occur in a short period. Continuous monitoring of microplastics in natural waters and targeted aquatic ecological restoration are essential to ensure the normal growth and reproduction of the wild population of C. guichenoti.