Selective Recovery of Cathode Materials from Spent Lithium-Ion Battery Material with a Near-Room-Temperature Separation.

Effective separation of cathode materials from the current collector is a critical step in recycling a spent lithium-ion battery (LIB). This typically necessitates the decomposition or dissolution of the organic binder, poly(vinylidene fluoride) (PVDF), to achieve efficient recovery of cathode materials. However, this process requires a high decomposition temperature, typically between 400 and 600 °C, and can lead to side reactions, such as current collector oxidation/brittleness, decomposition of cathode materials, and formation of metal fluorides. In this study, we propose that non-thermal plasma (NTP) treatment can be used to achieve an extremely high separation of cathode materials and aluminum current collector at near room temperature. Instead of relying on PVDF decomposition, which requires high temperatures, PVDF can be deactivated by partially breaking down long molecular chains with appropriate NTP conditions. With a total treatment time of around 2000 s and an environmental temperature of approximately 80 °C, minor side reactions can be avoided. The separation rate can reach up to 95.69%, and high-quality cathode materials can be obtained with only 0.02 wt % aluminum impurity content. This research could potentially offer a new approach toward minimizing recycling steps and reducing energy consumption in the recycling of spent LIBs. It could also be extended to the recovery of a broader range of electronic wastes.

Toxicological effects induced by two carbamates on earthworms (Eisenia fetida): Acute toxicity, arrested regeneration and underlying mechanisms.

Eisenia fetida is recognised as advantageous model species in ecotoxicological and regeneration investigations. The intensive utilization of carbamate pesticides (CARs) imposes heavy residue burdens and grave hazards on edaphic environments as well as soil fauna therein. However, precise mechanisms whereby the specific CAR exerted toxic effects on earthworms remain largely elusive, notably from regenerative perspective. Herein, acute responses and regenerative toxicity of two carbamates (metolcarb, MEB and fenoxycarb, FEB) against E. fetida were dissected using biochemical, histological as well as molecular approaches following OECD guidelines at the cellular, tissue and organismal level. The acute toxicity data implied that MEB/FEB were very toxic/medium to extremely toxic, respectively in filter paper contact test and low to medium toxic/low toxic, respectively in artificial soil test. Chronic exposure to MEB and FEB at sublethal concentrations significantly mitigated the soluble protein content, protein abundance while enhanced the protein carbonylation level. Moreover, severely retarded posterior renewal of amputated earthworms was noticed in MEB and FEB treatments relative to the control group, with pronouncedly compromised morphology, dwindling segments and elevated cell apoptosis of blastema tissues, which were mediated by the rising Sox2 and decreasing TCTP levels. Taken together, these findings not only presented baseline toxicity cues for MEB and FEB exposure against earthworms, but also yielded mechanistic insights into regenerative toxicity upon CAR exposure, further contributing to the environmental risk assessment and benchmark formulation of agrochemical pollution in terrestrial ecosystem.

A sustainable approach for selective recovery of lithium from cathode materials of spent lithium-ion batteries by induced phase transition.

Recycling of spent lithium-ion batteries (LIBs) has attracted widespread attention because of their dual attributes to environmental protection and resource conservation. Utilization of strong corrosive acids is currently the preferred way to recover valuable metals from spent LIBs, but the extensive use of chemical reagents can pose serious environmental risks. Herein, this research proposes a green process for selective recovery of lithium using the material of spent LIBs itself without adding exogenous reagents, mechanochemistry induced phase transition. The leaching efficiency of Li can reach 94% by employing the copper foil separated from spent LIBs as the co-grinding additive during the mechanochemical reaction process. Then, the high value LiOH·H2O can be prepared through direct evaporation and crystallization without adding any precipitant. Meanwhile, cobalt is almost remained in the leaching residue which can be recovered through a step-by-step separation process. XRD, XPS, and SEM-EDS characterizations show that LiCoO2 and copper foil are transformed into the soluble Li2O, and insoluble CuO and CoO under the mechanical force. Finally, the soluble Li2O is dissolved in water to prepare the LiOH solution, and the insoluble CuO and CoO are transformed into Cu2O and Co(OH)2. On the basis of the experimental investigation, it is proven that the proposed process is suitable for selectively recovering Li from all types of cathode materials without generating salty wastewater or introducing chemical reagents. Thus, the proposed approach can ensure the efficient recovery of valuable metals from spent LIBs while avoiding the potential threat to the environment and human health.

Manipulating Selectivity of Hydroxyl Radical Generation by Single-Atom Catalysts in Catalytic Ozonation: Surface or Solution.

Hydroxyl radical-dominated oxidation in catalytic ozonation is, in particular, important in water treatment scenarios for removing organic contaminants, but the mechanism about ozone-based radical oxidation processes is still unclear. Here, we prepared a series of transitional metal (Co, Mn, Ni) single-atom catalysts (SACs) anchored on graphitic carbon nitride to accelerate ozone decomposition and produce highly reactive ·OH for oxidative destruction of a water pollutant, oxalic acid (OA). We experimentally observed that, depending on the metal type, OA oxidation occurred dominantly either in the bulk phase, which was the case for the Mn catalyst, or via a combination of the bulk phase and surface reaction, which was the case for the Co catalyst. We further performed density functional theory simulations and in situ X-ray absorption spectroscopy to propose that the ozone activation pathway differs depending on the oxygen binding energy of metal, primarily due to differential adsorption of O3 onto metal sites and differential coordination configuration of a key intermediate species, *OO, which is collectively responsible for the observed differences in oxidation mechanisms and kinetics.

Effects of Bacillus subtilis A-5 and its fermented γ-polyglutamic acid on the rhizosphere bacterial community of Chinese cabbage.

Chemical fertilizer reduction combined with novel and green agricultural inputs has become an important practice to improve microecological health in agricultural production. Given the close linkages between rhizosphere processes and plant nutrition and productivity, understanding how fertilization impacts this critical zone is highly important for optimizing plant-soil interactions and crop fitness for agricultural sustainability. Here, by using a pot experimental system, we demonstrated that nitrogen fertilizer reduction and microbial agent application promoted plant fitness and altered the microbial community structure in the rhizosphere soil with the following treatments: no fertilization, CK; conventional chemical fertilizer, CF; 30% reduced nitrogen fertilizer, N; 30% reduced nitrogen fertilizer with pure γ-PGA, PGA; 30% reduced nitrogen fertilizer with Bacillus subtilis A-5, A5; 30% reduced nitrogen fertilizer with γ-PGA fermentation broth, FJY. The PGA, A5, and FJY treatments all significantly promoted crop growth, and the FJY treatment showed the strongest positive effect on Chinese cabbage yield (26,385.09 kg/hm2) (P < 0.05). Microbial agents affected the α diversity of the rhizosphere bacterial community; the addition of B. subtilis A-5 (A5 and FJY treatments) significantly affected rhizospheric bacterial community structure. Urease activity and soil pH were the key factors affecting bacterial community structure and composition. The FJY treatment seemed to influence the relative abundances of important bacterial taxa related to metabolite degradation, predation, and nitrogen cycling. This discovery provides insight into the mechanism underlying the effects of microbial agent inputs on rhizosphere microbial community assembly and highlights a promising direction for the manipulation of the rhizosphere microbiome to yield beneficial outcomes.

Effects of fertilizer application on phthalate ester pollution and the soil microbial community in plastic-shed soil on long-term fertilizer experiment.

Due to the use of agricultural film, the pollution of phthalate esters (PAEs) in plastic-shed soils has attracted increasing attention. In this study, we used watermelon as a planting system and investigated the effects of organic fertilizer and chemical fertilizer application on the degradation of PAEs by evaluating soil nutrients and soil bacterial communities in plastic-shed soil. The dibutyl phthalate (DBP) concentration in the organic fertilizer soil was only 58.2% in the zero-fertilization control (CK) soil, but the concentrations of monohexyl phthalate (MEHP) and mono-n-butyl ester (MBP), the metabolites of PAEs, were found to be higher. The concentration of MBP is ten times that of DBP. The results showed that fertilization, especially the application of organic fertilizers, had a significant effect on the degradation of PAEs. There were specific biomarkers in different fertilization treatments. Among the microbiome community, Planifilum had the highest relative abundance in the organic fertilizer (OF) soil, and the highest proportion of Thermodesulfovibrionia was detected in the chemical fertilizer (CF) soil. These biomarkers were significantly correlated with PAEs and their metabolites. The relative abundance of Thermomonosporaceae was significantly positively correlated with DBP. Planifilum and Thermaerobacter, which significantly increased in organic fertilizer soil, showed a significant negative correlation with DBP and a significant positive correlation with MBP. The relative abundances of Planifilum and Geobacillus were elevated in the OF soil and may be able to co-metabolize soil nitrogen and PAEs. PAEs and their metabolites in soils had significant effects on soil microbes, as did the soil nutrients including available phosphorus (AP), alkali-hydrolysable nitrogen (Alkali-N), and organic matter (OM). Our research provides scientific support for the use of fertilizers to reduce PAE contamination but also warns of the potential risks of PAE metabolites.

Removal of sulfamethoxazole and antibiotic resistance genes in paddy soil by earthworms (Pheretima guillelmi): Intestinal detoxification and stimulation of indigenous soil bacteria.

Vermiremediation, which use earthworms to remove contaminants from soil, has been proven to be an alternative, low-cost technology. However, the effects of earthworm activity, especially the degraders in earthworm intestines, on the fate of sulfamethoxazole (SMX), and the effects of intestinal bacteria on degrading bacteria in soil are unclear. In this study, the effects of earthworms on the fate of SMX and related antibiotic resistance genes (ARGs) were investigated. Special attention was paid to the impact of earthworms on SMX degradation efficiency, degradation products, related ARGs, and degraders in both soil and earthworm intestines; the effect of intestinal bacteria on soil bacteria associated with SMX was also studied. Earthworms significantly accelerated SMX degradation by both intestinal detoxification and the stimulation of indigenous soil bacteria. Compared with the treatment without earthworms, the treatment with earthworms reduced SMX residues by 25.1 %, 49.2 %, 35.7 %, 34.2 %, and 35.7 % on the 10th, 20th, 30th, 60th, and 90th days, respectively. Compared with those in soil (treated with earthworms), the SMX residues in wormcasts were further reduced by 12.2-29.0 % from the 2nd to the 20th day, producing some unique anaerobic degradation products that were distinct from those in the soil. In earthworm intestines, SMX degradation was enhanced by bacteria of the genera Microvirga, Sphingomonas, Methylobacterium, Bacillus, and Tumebacillus. All of these bacteria (except Bacillus spp.) entered and colonised the soil with wormcasts, further promoting SMX degradation. Additionally, earthworms removed a significant number of ARGs by increasing the fraction of potential SMX degraders and inhibiting the potential hosts of ARGs and int1. This study demonstrated that earthworms could remediate SMX-contaminated soil by enhancing the removal of SMX and ARGs.

γ-Polyglutamic Acid Production, Biocontrol, and Stress Tolerance: Multifunction of Bacillus subtilis A-5 and the Complete Genome Analysis.

Bacillus subtilis A-5 has the capabilities of high-molecular-weight γ-PGA production, antagonism to plant pathogenic fungi, and salt/alkaline tolerance. This multifunctional bacterium has great potential for enhancing soil fertility and plant security in agricultural ecosystem. The genome size of B. subtilis A-5 was 4,190,775 bp, containing 1 Chr and 2 plasmids (pA and pB) with 43.37% guanine-cytosine content and 4605 coding sequences. The γ-PGA synthase gene cluster was predicted to consist of pgsBCA and factor (pgsE). The γ-PGA-degrading enzymes were mainly pgdS, GGT, and cwlO. Nine gene clusters producing secondary metabolite substances, namely, four unknown function gene clusters and five antibiotic synthesis gene clusters (surfactin, fengycin, bacillibactin, subtilosin_A, and bacilysin), were predicted in the genome of B. subtilis A-5 using antiSMASH. In addition, B. subtilis A-5 contained genes related to carbohydrate and protein decomposition, proline synthesis, pyruvate kinase, and stress-resistant proteins. This affords significant insights into the survival and application of B. subtilis A-5 in adverse agricultural environmental conditions.

Quantitative Proteomics of Chromochloris zofingiensis Reveals the Key Proteins Involved in Cell Growth and Bioactive Compound Biosynthesis.

Glucose metabolism regulates cell growth and affects astaxanthin accumulation in the green algae Chromochloris zofingiensis. Hub gene functioning in this bioactive compound has been illustrated at the genome, transcriptome and metabolome level, but is rather limited from a proteome aspect. Microalgal cell produce an enhanced biomass (8-fold higher) but decreased lipid and astaxanthin content (~20% less) in the glucose condition compared to the control. Here, we investigate the proteomic response of C. zofingiensis grown with and without glucose using an LC-MS/MS-based Tandem Mass Tag (TMT) approach. The proteomic analysis demonstrated that glucose supplementation triggers the upregulation of 105 proteins and downregulation of 151 proteins. Thus, the carbon and energy flux might flow to cell growth, which increased the associated protein abundance, including DNA polymerase, translation initiation factor, 26S proteasome regulatory subunits, and the marker enzyme of the TCA cycle ribosomal protein. Moreover, the glucose supplement triggered the downregulation of proteins mainly involved in photosynthesis, chloroplasts, valine, leucine and isoleucine biosynthesis, 2-oxocarboxylic acid metabolism, and pantothenate and CoA biosynthesis pathways. This proteomic analysis is likely to provide new insights into algal growth and lipid or astaxanthin accumulation upon glucose supplementation, providing a foundation for further development of C. zofingiensis as oleaginous microalga for bioengineering applications.

Asian Swamp eel Monopterus albus Population Structure and Genetic Diversity in China.

The Asian swamp eel (Monopterus albus) is one of the most widely distributed freshwater fish in China. In this study, we identified the single nucleotide polymorphisms (SNPs) of M. albus from 19 wild populations in China using restriction-site associated DNA sequencing (RAD-seq), and used SNP markers to investigate the swamp eel the genetic diversity and population genetic structure. A total of 8941794 SNPs were identified. Phylogenetic and principal component analysis suggested that the 19 populations were clustered into four groups: The Jiaoling County (JL) and Poyang Lake (PYH)populations in Group Ⅰ; the Chengdu City (CD), Dali City (YN), Eli Village (EL), Dongting Lake (DTH), Huoqiu County (HQ), and Chaohu Lake (CH) populations in Group Ⅱ; the Puyang City (PY), Chongming Island (CM), Tai Lake (TH), Gaoyou Lake (GYH), Weishan Lake (WSH), Haimen City (HM), Hongze Lake (HZH), Baiyangdian Lake (BYD), Dagushan (DGS), and Pinghu City (PH) populations in group Ⅲ; and the Lingshui County (LS) populations in Group Ⅳ. All 19 populations may have evolved from four ancestors. The genetic diversity was relatively high in CM, GYH, and HM; and low in LS, EL, and JL. The LS, and CM populations had the highest and lowest differentiation from the other populations, respectively. These findings provide new insights for germplasm resources protection and artificial breeding of M. albus.

Effects of straw returning combined with earthworm addition on nitrification and ammonia oxidizers in paddy soil.

Introduction: Soil ammonia oxidation, which acts as the first and rate-limiting step of nitrification, is driven by ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA) and complete ammonia oxidizer (comammox, amoA gene of clade-A and clade-B). Straw returning, widely used ecological technology in China, is an effective measure for promoting straw decomposition and soil nutrient cycling when combined with earthworm addition. However, the effects of straw returning combined with earthworm addition on soil ammonia oxidizers remain poorly understood. Methods: A 2-year plot experiment was conducted with 5 treatments: no fertilizer (CK); regular fertilization (RT); straw returning (SR); earthworm addition (W); straw returning + earthworm addition (SRW). The AOA, AOB, comammox clade-A and clade-B community microbial diversities and structures were investigated by high-throughput sequencing. Results: The results showed that (1) compared to RT treatment, W, SR, and SRW treatments all significantly increased the richness of AOA and comammox clade-A and clade-B (p < 0.05), and the richness of AOB was only significantly promoted by SRW treatment (p < 0.05). However, only SRW had a higher comammox clade-B diversity index than RT. (2) The ammonia oxidizer community structures were altered by both straw returning and earthworm addition. Soil NH4 +-N was the critical environmental driver for altering the ammonia oxidizer community structure. (3) Compared with RT treatment, the soil potential nitrification rate (PNR) of W and SRW treatments increased by 1.19 and 1.20 times, respectively. The PNR was significantly positively correlated with AOB abundance (path coefficient = 0.712, p < 0.05) and negatively correlated with clade-B abundance (path coefficient = -0.106, p < 0.05). Discussion: This study provides scientific support for the application of straw returning combined with earthworm addition to improve soil nitrification with respect to soil ammonia-oxidizing microorganisms.

Using Mathematical Models to Study the Influences of Different Ratios of Chemical Nitrogen, Phosphorus, and Potassium on the Content of Soluble Protein, Vitamin C, and Soluble Sugar in Melon.

The current fertilizer recommendations for melon plantation have many limitations and exhibit deficiencies regarding future development. Therefore, in this study, the optimal quantities of fertilizer, in terms of the effects of single factors and interaction effects, are studied. There were significant interaction effects between N and P, N and K, P and K; the contents of soluble protein, vitamin C (Vc), and soluble sugar in melon could be improved using the optimal fertilization ratios. The optimal ratio of N:P:K was 2.33:1:3.85, with the amounts of N, P2O5, and K2O, respectively, being 157.5, 67.58, and 260.38 kg/hm2, yielding 8.73 g/kg of soluble protein in melon. The optimal ratio of N:P:K was 2.03:1:3.36, with amounts of N, P2O5, and K2O being 157.50, 77.40, and 260.38 kg/hm2, respectively, yielding 25.32 g/kg Vc content in melon. Finally, the optimal ratio of N:P:K was 1.53:1:3.36, with the amounts of N, P2O5, and K2O being 118.07, 77.40, respectively, and 260.38 kg/hm2, yielding 13.34% soluble sugar content in melon.

Combination application of elemental sulfur and earthworm increased the lead (Pb) uptake by ryegrass (Lolium perenne L.) in contaminated agricultural soil.

The phytoremediation efficiency is largely depends on the bioavailability of heavy metal in soil. The activity of earthworms and oxidation of elemental sulfur (S0) in soil has influence on heavy metal speciation transformation in soil. By conducting pot experiment, we examined the possibility of enhancing phytoextraction efficiency of lead (Pb) in soil by ryegrass (Lolium perenne L.) with application of both S0 and earthworms. Results showed that the addition of S0 decreased soil pH and increased soil CEC, while a slight trend of decrease for soil pH and increase for CEC was found with earthworm application. In soil treated with earthworms, the addition of S0 increased the concentration of DTPA-extractable Pb by 9.9~20.8%. The concentration of diffusive gradients in thin film (DGT)-extractable Pb was increased by 26.31~32.9% with S0 and earthworm addition. In soil treated with earthworms, the addition of S0 increased the concentration of Pb in shoots of ryegrass by 55.7~110.4% and the translocation factor of Pb in ryegrass was also increased by S0 addition. Our results suggested that the combination application of earthworms and S0 could be an effective way to enhance the remediation efficiency of ryegrass for Pb-contaminated soil.

Effects of insecticides on malacostraca when managing diamondback moth (Plutella xylostella) in combination planting-rearing fields.

The combination of crop planting and animal rearing in the same area is popular. However, if the methods of planting and rearing are not appropriate, it will result in losses and the disruption of pest management. The toxicities of 17 insecticides to Plutella xylostella, Eriocheir sinensis, and Procambarus clarkii were tested. The recommended maximum field doses were used in 2 d and 4 d bioassays, and the levels of resistance of P. xylostella to insecticides were determined. Of five insecticides that had relatively low toxicity to E. sinensis and P. clarkii, spinetoram and MbNPV showed the best control efficacy of P. xylostella, followed by tetrachlorantraniliprole, chlorantraniliprole, and avermectin. P. xylostella had relatively little resistance to spinetoram, MbNPV, chlorantraniliprole, and avermectin. Therefore, we concluded that the best insecticides suitable for combination planting and rearing fields (cauliflower-crab or cauliflower-crayfish) were spinetoram and MbNPV, followed by chlorantraniliprole and avermectin. Other insecticides, such as emamectin benzoate, indoxacarb, and chlorfenapyr were effective at controlling P. xylostella, but they were not suitable for use in combination planting and rearing fields because of their high toxicity to crabs and crayfish.

Straw return promoted the simultaneous elimination of sulfamethoxazole and related antibiotic resistance genes in the paddy soil.

Straw return could provide a natural available carbon source for the soil microorganisms, which might affect the environmental behaviours of organic pollutants. In this study, microcosm system was constructed to investigate the effect of rice straw return on the fate of sulfamethoxazole (SMX) and related antibiotic resistance genes (ARGs). The results showed that straw return (1% of soil dry mass) could accelerate the degradation of SMX via co-metabolism. In the treatment group with rice straw, SMX was rapidly decomposed into small molecular compounds (e.g., (Z)-1-amino-3-oxobut-1-en-1-aminium and benzenesulfinic acid) within the first six days, and SMX was undetectable after 60 days; while for the SMX group without rice straw, 1.3 mg kg-1 of SMX still remained at the 60th day. Straw return could enhance the relative abundances of Proteobacteria involved in SMX degradation, including Microvirga and Ramlibacter, which co-metabolized SMX via the degradation pathways of mineralizable components and aromatic compound. Furthermore, straw return significantly eliminated the ARGs. After 60 days, the int1 and sul1 abundances of the treatment group with rice straw were less than one-tenth of the SMX group without rice straw. The redundancy and network analysis of bacterial community and environmental factors showed that dissolved organic carbon and bacteria belonged to Proteobacteria and Actinobacteria might play positive roles in eliminating ARGs. Our results demonstrate that straw return could promote the simultaneous elimination of SMX and corresponding ARGs, which provides a promising approach to effectively treat antibiotics and ARGs in the farmland.

Diatomite Dynamic Membrane Fouling Behaviour during Dewatering of Chlorella pyrenoidosa in Aquaculture Wastewater.

Combined microalgal and membrane filtration could effectively treat aquaculture wastewater; however, the membrane fouling induced by extracellular organic matter (EOM) during the dewatering process is an issue. This study investigated diatomite dynamic membrane (DDM) fouling behaviour during the dewatering of Chlorella pyrenoidosa under the influence of copper ions. The results indicate that copper ion heavy metals in aquaculture wastewater significantly affected purification and algae dewatering by DDM. Aquaculture wastewater with a high copper concentration (1 and 0.5 mg/L) could induce serious DDM fluxes and cake layer filtration resistance (Rc), whereas fewer filtration fluxes were induced when aquaculture wastewater had a low copper concentration, particularly that of 0.1 mg/L, at which the Rc was lowest and the concentration effect was highest. Macromolecular organics of EOM, such as biopolymers, polysaccharides, and proteins, were responsible for DDM fouling and accumulated mostly in the slime layer, whereas only a small amount of them accumulated in the diatomite layer. The DDM rejected more protein-like organics of EOM in the slime layer when dewatering algae at low copper concentrations (<0.1 mg/L); however, when using the DDM to dewater algae at high copper concentrations, more polysaccharides of EOM were rejected (0.5 < Cu2+ < 5 mg/L). This result has significant ramifications for aquaculture wastewater treatment as well as algae separation and concentration by the DDM.

Effects of Biogas Slurry Combined With Chemical Fertilizer on Soil Bacterial and Fungal Community Composition in a Paddy Field.

The application of biogas slurry and chemical fertilizer in paddy fields can be a practical method to reduce the environmental risk and utilize the nutrients of biogas slurry. The responses of bacterial and fungal communities to the application of biogas slurry and chemical fertilizer are important reflections of the quality of the ecological environment. In this study, based on a 3-year field experiment with different ratios of biogas slurry and chemical fertilizer (applying the same pure nitrogen amount), the Illumina MiSeq platform was used to investigate the bacterial and fungal community diversity and composition in paddy soil. Our results revealed that compared with the observations under regular chemical fertilization, on the basis of stable paddy yield, the application of biogas slurry combined with chemical fertilizer significantly enhanced the soil nutrient availability and bacterial community diversity and reduced the fungal community diversity. Dissolved organic carbon (DOC), DOC/SOC (soil organic carbon), available nitrogen (AN) and available phosphorus (AP) were positively correlated with the bacterial community diversity, but no soil property was significantly associated with the fungal community. The bacterial community was primarily driven by the application of biogas slurry combined with chemical fertilizer (40.78%), while the fungal community was almost equally affected by the addition of pure biogas slurry, chemical fertilizer and biogas slurry combined with chemical fertilizer (25.65-28.72%). Biogas slurry combined with chemical fertilizer significantly enriched Proteobacteria, Acidobacteria, Planctomycetes, Rokubacteria, and Ascomycota and depleted Chloroflexi, Bacteroidetes, Crenarchaeota, Basidiomycota, and Glomeromycota. The observation of the alteration of some bacteria- and fungus-specific taxa provides insights for the proper application of biogas slurry combined with chemical fertilizer, which has the potential to promote crop growth and inhibit pathogens.

Toxicity of isoprocarb to earthworms (Eisenia fetida): Oxidative stress, neurotoxicity, biochemical responses and detoxification mechanisms.

Isoprocarb (IPC) is a conventional carbamate with high insecticidal activity, however, generalized use of it may cause soil contamination and adversely implicate non-target biota. Following OECD standardized toxicological protocols, the toxic effects of IPC on Eisenia fetida at lethal and sublethal concentrations were examined to elucidate its toxic modes of action as well as biochemical and detoxification responses of E. fetida. Acute toxicity tests showed that IPC induced a concentration-dependent rise of mortality, with LC50 of 8.20 µg/cm2 (48 h) in FPCT and 3.37 mg/kg (14 d) in AST, respectively. The ecotoxicological effects of IPC chronic exposure were measured by physiochemical, qRT-PCR and western blot analysis. Specifically, ROS, MDA and 8-OHdG contents were enhanced and T-AOC, SOD, CAT and POD activities diminished with increasing concentrations. While activities of CYP3A4 and CarE as well as expressions of Hsp70, GPx and GST were elevated upon IPC treatments, responsible for detoxifying mechanisms as implied by principal component analysis (PCA). Meanwhile, IPC diminished NRRT and inhibited AChE activities along with expressions of AChE-related genes. All these striking alterations between IPC-exposed earthworms and controls were illustrated in PCA model. More importantly, growth, reproductive and regenerative toxicity of IPC were observed with reduced cast production and soluble protein content, suppressed ANN protein and gene expressions, reversely modulated TCTP and Sox2 gene and protein, respectively. Taken together, deleterious perturbations could be induced by IPC in biophysiological homeostasis of E. fetida primarily through oxidative stress and neural dysfunction. This study not only highlighted potential hazard of IPC to earthworms in the terrestrial ecosystem, but also expounded upon mechanisms underlying toxic modes of action for IPC and detoxification of earthworms.

Effects of common rice field weeds on the survival, feeding rate and feeding behaviour of the crayfish Procambarus clarkii.

To check if it is possible for crayfish to reduce the weed biomass in a paddy field, we hypothesised that crayfish can feed on common weeds in a paddy field. The feeding ability of red swamp crayfish, Procambarus clarkii, males and females for 4 weeds, Ludwigia prostrata Roxb., Leptochloa chinensis (L.) Nees, Echinochloa crusgalli (L.) Beauv and Eclipta prostrata L., commonly found in rice-crayfish fields were evaluated using a quantitative feeding experiment and behaviour observation experiment. The results of the quantitative feeding and behaviour experiments were highly consistent. The P. clarkii gender and weed species had no interactive effects on survival rate, the daily feed intake (FI) and percentage of daily feed intake (PFI). The results of the quantitative feeding experiment showed that the FI and PFI values of both P. clarkii females and males were significantly higher in the P. clarkii feed group than in the weed treatment group. Both FI and PFI were significantly higher in the L. chinensis group than in the other treatment groups. The survival rate of P. clarkii was significantly lower in the E. crusgalli group than in the other treatment groups. The behaviour observation experiment showed that the feeding frequency and duration were in the order of L. chinensis > E. prostrata > L. prostrata > E. crusgalli. The results indicate that the P. clarkii specimens liked to eat L. chinensis (mean PFI was more than 2%), hardly fed on E. crusgalli.

Effects of long-term integrated agri-aquaculture on the soil fungal community structure and function in vegetable fields.

The diversity and community structure of soil fungi play an important role in crop production and ecosystem balance, especially in paddy-upland vegetable field systems. High-throughput sequencing was used to study changes in the soil fungal community structure and function in paddy-upland vegetable field systems. The results showed that compared with traditional planting, the diversity and community structure of soil fungi were changed by the combination of flooding and drought, the Shannon index increased by 11.07%, and the proportion of the dominant species, Mortierella, decreased by 22.74%. Soil available nitrogen, total phosphorus, available phosphorus, total nitrogen and organic matter played a leading role in the initial stage of the experiment, while the dominant factor changed to total potassium 3 years later and then to soil pH and water content 6 years later. FUNGuild analysis showed that the proportion of three independent trophic modes of soil fungi were increased by the combined flooded-drought model, and there were multiple interaction factors, For example, nutrient supply, pH and planting pattern. This study showed that soil fertility, crop yield and economic benefits were better than the traditional model after three years of planting and breeding. The longer the time, the better the effect.