The application of poly(butylene adipate-co-terephthalate) (PBAT) biodegradable plastics has long been constrained by insufficient light aging resistance. Hindered amine light stabilizers (HALSs), known as eco-friendly additives, can scavenge free radicals to enhance polymer durability. However, rough choices have resulted in wastage of resources and environmental pressure. Based on the application of plastic films as the background for use, this study systematically evaluates application effects of five HALSs. The films underwent accelerated aging for various durations and were further investigated by a combination of experiments and molecular simulation. Results showed that all HALSs mitigated PBAT light aging, with Chimassorb-944 (UV-944) and Tinuvin-770 (UV-770) performing the best for real applications. Quantum chemical calculation results showed that UV-944 had stronger anti migration ability. After 300 h of aging, films with UV-944 and UV-770 retained superior tensile strength and elongation at break in the transverse direction compared to neat PBAT films. Polymeric HALSs provided better long-term stability than small-molecule ones. Further spectra analysis indicated that stronger C—O bonds in HALS/PBAT composites correlated with improved photostability. This study offers valuable insights into improving weather resistance of PBAT biodegradable films and optimizing the real application of HALSs.

While biochar is widely promoted as a soil amendment for enhancing nutrient availability and carbon sequestration, its long-term effectiveness across diverse soil types under intensive cultivation remains poorly understood. This study quantified temporal dynamics of biochar-induced nutrient changes across two contrasting soils (Dystrudept and Hapludult) over eight years (2018–2025), evaluating five application rates (0, 5, 15, 20, and 40 t ha−1) through 18 repeated soil samplings under continuous tobacco cultivation. Biochar application produced strong initial responses in soil pH, organic carbon (SOC reaching 83.59 g kg−1 at 40 t ha−1 in Hapludult), and available nutrients, but these effects progressively diminished, with complete convergence across all treatments by year 6–8 regardless of initial application rate or soil type—a critical finding that fundamentally challenges assumptions of permanent biochar effectiveness. Structural equation modeling identified pH-mediated pathways (λ = 0.99***) driving base cation availability, with temporal factors consistently eroding nutrient pools. Strikingly, the sandy loam Dystrudept exhibited 40

Salt stress severely inhibits plant growth and negatively impacts crop yield. Auxin response factors (ARFs) play crucial roles in plant growth and development and are involved in multiple signaling pathways as well as responses to abiotic stresses. However, the molecular mechanisms by which ARFs mediate plant responses to salt stress and ABA signaling remain largely unclear. In this study, we cloned a novel tobacco ARF family gene, NtARF2, which is significantly downregulated under salt stress and exogenous ABA treatment. NtARF2 is localized in the nucleus, and its knockout increases the K/Na ratio and ABA content in tobacco, thereby markedly enhancing salt tolerance. Furthermore, NtARF2 knockout affects stomatal size, photosynthetic performance, and antioxidant capacity. Yeast two-hybrid (Y2H) and luciferase complementation imaging (LCI) assays indicate that NtARF2 interacts with NtABI3, suggesting that it may play a key role in the crosstalk between salt stress and ABA signaling pathways. This study provides new insights into the functional role of ARF2 in tobacco salt tolerance and offers a theoretical foundation for the development of salt-tolerant crop varieties.

Eight-year consecutive field experiments were conducted at two locations (Heishi and Linquan, Bijie, Guizhou, China) to investigate the optimum biochar application frequencies for sustaining soil nutrients and crop quality. A randomized complete block design with three treatments (annual, biennial, triennial) and three replicates was established using flue-cured tobacco as a test crop. Biochar derived from tobacco stems was applied at a rate of 7.5 Mg ha-1 per application according to treatment frequency, and multi-component fertilizer was applied each year. Soil samples were collected at 12 times for nutrients and enzyme activity analyses. Results showed that annual application significantly increased soil pH by 0.67-0.70 compared to triennial treatments, and soil organic carbon (SOC) by 38%-62% in Hapludult and 17%-46% in Dystrudept. Annual application substantially increased available K by 35%-53% increases over triennial treatments. However, annual application also elevated soluble chloride (Cl-) by 56%-134%. Structural equation modeling revealed that frequency primarily controlled pH, SOC, and soluble Cl. Soil enzyme activities increased by 18%-45% under annual versus triennial applications. For tobacco leaves, annual application increased total sugar accumulation, while biennial and triennial applications improved potassium/chlorine (K/Cl) ratios. Site-specific responses were evident, with Hapludult showing stronger frequency effects than Dystrudept. These findings suggest that a 2-3 years biochar application interval, tailored to soil type, provides optimal balance between soil nutrient enhancement, microbial activity, and tobacco quality while mitigating excessive Cl accumulation.

Poly (butylene adipate-co-butylene terephthalate) (PBAT) biodegradable mulch film may pose ecological risks to the soil environment. However, its environmental impacts on karst yellow soil remain unclear. Hence, this study combined 16S rRNA sequencing with soil pseudo-targeted metabolomics to investigate the effects of PBAT degradation at three dosage levels on karst yellow soil. Results showed that PBAT exerted dosage-dependent effects on soil available nutrients and enzyme activities. Specifically, alkali-hydrolyzable nitrogen (AHN) and available phosphorus (AP) decreased, while available potassium (AK) increased. Most soil enzymes generally increased in the early stage and stabilized in the later stage; however, soil polyphenol oxidase (S-PPO) exhibited a trend of initial promotion followed by inhibition. PBAT degradation drove the temporal succession of the bacterial communities, shifting them from a relatively stable initial state to a composition enriched in PBAT-degrading taxa (e.g., Sphingomonas, Novosphingobium, and Chujaibacter). This microbial shift was accompanied by the enrichment of metabolic functions associated with degradation. Soil pseudo-targeted metabolomic analysis revealed that PBAT degradation altered the soil metabolic profile. At the early stage (120 days), stress-response pathways were activated to maintain microbial homeostasis. At the later stage (240 days), metabolic activity shifted toward modulating amino acid, energy, and carbohydrate pathways in response to persistent degradation. Furthermore, a richer correlation network formed between soil bacteria and metabolites in the later stage. This study demonstrates that PBAT influences the soil bacterial microbiome and alters metabolome dynamics in karst yellow soil, providing a certain theoretical basis for understanding its ecological impact and guiding its safe application.

Fel d1 is the most important allergen secreted by cats, which can trigger asthma in sensitive individuals. Our objective was to knock-out the Fel d1 gene in the fetal fibroblasts of cats through CRISPR-Cas9 technology with two sgRNAs and to determine the impact of such mutations on the antigenicity of the Fel d1 protein. DNA samples from 38 domestic cats were collected and amplified by PCR to obtain the complete sequence of the Fel d1 gene. Throughout evolution, Fel d1 polypeptide chain 1(CH1) has proven to be much more conserved than Fel d1 polypeptide chain 2(CH2); therefore, we targeted CH2 and designed two single-guide RNAs (CH2-sgRNA-1 and CH2-sgRNA-2) for this region. Using these constructed sgRNAs, we performed gene knock-out in fetal fibroblasts, resulting in two mutations within the target gene. Following this, DNA was extracted and the target site product was cloned using TA cloning via PCR, and a single colony from this process was sequenced to analyze the physicochemical properties, antigenic sites, and three-dimensional structure of the mutated protein. The results revealed that there were 12 and 51 polymorphic loci (single-nucleotide polymorphisms, or SNPs) found in the CH1 and CH2 sequences, respectively, with most loci located in the GC-rich intron 2, while others were found in exon 2, intron 3, and exon 3. These SNPs guided sgRNA design by identifying conserved regions in the CH2 gene. The gene editing efficiency for the CH2 region, with this dual CRISPR system, was 40%, with 35% attributed to Type 1 mutation and 5% to Type 2 mutation. In conclusion, CH1 is significantly more conserved than CH2, and the antigenicity of the Fel d1 CH2 gene in domestic cats can be effectively reduced through CRISPR-Cas9 gene editing.

As the mechanism of the soil-fungi -plant interaction under the tobacco intercropping model is unclear, and the contribution of this triple interaction to tobacco plant growth is still difficult to predict, so, in this paper, Illumina high-throughput sequencing technology was used to analyze the effects of monoculture (CK) and intercropping with garlic (T1 and T2 treatments) on rhizosphere soil nutrients, enzyme activities, fungal community, tobacco plant growth, and to evaluate the regulation of rhizosphere soil microenvironment and plant productivity on intercropping. The results showed that intercropping significantly increased the nutrient, enzyme activity, fungal community diversity of rhizosphere soil and tobacco plant biomass. Although the dominant fungi in each treatment were the same at the gate level, the distribution ratio of dominant fungi was different. Correlation analysis showed that Ascomycota was positively correlated with all the nutrient and enzyme activity indexes, and the nutrient and enzyme activity indexes were positively correlated with the tobacco plants growth, which strongly indicated that the soil microenvironment under intercropping had a potential effect on the production performance of tobacco plants. In conclusion, tobacco intercropping not only increased the plants biomass, significantly improved the nutrients and enzyme activities of rhizosphere soil, optimized the composition and diversity of fungal community, which may be the result of soil-fungi-plant interaction. 由于在烤烟间作种植模式下土壤-真菌-植物相互作用的机制尚不清楚，且这种三重相互作用对烟株生长的贡献仍难以预测，因此本文采用Illumina高通量测序技术分析了烤烟单作（CK）和与大蒜间作（T1和T2处理）对烟株根际土壤养分、酶活性、真菌群落组成和烟株生长发育的影响，评价了间作对烟株根际土壤微环境和烟株生产力的调控。结果表明：烤烟间作大蒜显著提高了烟株根际土壤的养分、酶活性、真菌群落的多样性和烟株的生物量；虽然各个处理在门水平上的优势真菌是一样的，但优势真菌的分布比例有差异。相关性分析表明，Ascomycota与所有的养分和酶活性指标均呈正相关，而养分和酶活性指标又与烟株生长发育呈正相关，这强烈表明间作下的土壤微环境对烟株的生产性能有潜在的作用。综上所述，烤烟间作不仅增加了烟株的生物量、显著提高了根际土壤养分和酶活性、优化了真菌群落的组成和多样性，而这些可能是土壤-真菌-植物三者相互作用的结果。

Abstract Purpose The soil-borne diseases have limited the development of agricultural production in Guizhou Province of southwest China which was caused by long-term continuous cropping of crops. To reduce the limit factors of continuous cropping of corps has become an urgent problem. Methods Reductive soil disinfestation (RSD) is an environmentally friendly soil amendment technology. In this study, high-throughput sequencing was used to investigate the mechanisms of RSD technology to improve long-term continuous cropping soil health. The examination focused on discerning how RSD influences the composition and structure of the rhizosphere microbial community. Result The results demonstrated that: (1) RSD treatment increased the content of soil organic matter (SOM), alkaline hydrolyzed nitrogen (AN), available phosphorus (AP), available potassium (AK) and pH; (2) RSD changed the fungal and bacterial community structure and the relative abundance of pathogenic microorganisms (e.g., Fusarium) was reduced, while the beneficial microorganisms (e.g., Trichoderma and Penicillium) was increased. (3) AN and pH had a greater impact on the bacterial community in the rhizosphere soil than on the fungal community. (4) RSD treatment improved the agronomic traits of tobacco and reduced the disease incidence of root rot disease. Conclusion Our results revealed that RSD treatment improved the physicochemical properties of continuous cropping tobacco soil and maintain the soil nutrient balance, resulting in the effective alleviation of continuous cropping barriers.

As the mechanism of the microbe-soil-tobacco interaction remains unclear and the contribution of tobacco plant growth is still difficult to predict, the chemical propertie and microbes of soil in tobacco/garlic intercropping system, the relevance of the soil chemical properties and the genes involved in C, N cycling and plant degradation (organic matter turnover) were studied by metagenome sequencing. The results showed that the intercropping treatment (T)significantly enhanced the content of organic matter(OM) ,the available nitrogen (AN) , the available phosphorus(AP) ,the available potassium content(AK), microbe number and the microbial biomass nitrogen,as well as the activity of urease , phosphatase ,invertase compared to monocropping treatment (CK), Especially the content of OM ,AN,AP,AK increased significantly by 29.46%,19.75%, 10.37%,17.42% in rhizosphere of T treatment than CK treatment. The content of polyphenol oxidase activity and microbial biomass carbon significantly decreased in T treatment with by 22.61% and 9.03% relative to CK treatment. Metagenomic analysis showed that the relative abundances of genes related to C cycling (ACA,sdhA,sdhB, sucD, mdh) , N cycling (glnA)and plant degradation (bglX) were higher in the T treatment than the CK treatment. Compared to the CK treatmen, the relative abundance of ACA, sdhA, sdhB, sucD,mdh,glnA and bglX were espectively 26.06%, 39.37%, 48.27%, 32.44%, 57.55%,14.28% and 2.39% higher in the T treatment. The intercropping system changed the chemical properties as well as the abundance of microbes, and subsequently regulate genes involved in C, N cycling and plant degradation, these improved the soil environment and leaded to the increase of tobacco plant biomass.

This study explored the changes in carbon components of tobacco-planting soil by the application of rice straw as organic materials to replace chemical fertilizers partially. Flue-cured tobacco was applied to the soil as base fertilizer to investigate the mineralization of soil organic carbon during its growing period. At 0 d, the humic acid carbon (HA-C), humin carbon (HM-C), HU ratio, PQ value and HM-C/(HA-C + FA-C) were 31.67, 31.40, 60.05, 28.01, and 27.75%, respectively which were higher than those of chemical fertilizer alone. At 30 d, the humus carbon (HE-C), HA-C, and fulvic acid carbon (FA-C) were 29.41, 20.97 and 30.49%, respectively. At 90 d, the A2920/1630 values were 227.43 and 232.32% higher than chemical fertilizer. Application of rice straw and decomposed rice straw with less fertilizer can increase the content of soil organic matter, HA-C, HM-C and FA-C in the tobacco-planting soil. This method increases the content of aliphatic chain hydrocarbons and reduces the amount of aromatic carbon, thus increasing aliphatic properties and decreasing the aromatic properties of soil. The treatment with chemical fertilizer reduction with decomposed rice straw also accelerates the formation and accumulation of stable components such as humic acid and humin and significantly improves the humification of soil humus.

Biochar application to soil has proven to be an excellent approach for decreasing the concentration of auto-toxic compounds and promoting plant growth in continuous-cropping fields. However, the mechanisms underlying the action pathway among biochars, auto-toxic compounds and tobacco remain unknown. In this study, we conducted an experiment tracking the incidence rate of black rot and auto-toxic compounds for a 3-year continuous-cropping tobacco pot trial in response to biochar treatment intensity compared with that of non-biochar treatment. Biochar inhibited the incidence of black rot. Using ultra-high-performance liquid chromatography–mass spectrometry (UPLC‒MS/MS), we revealed that biochar can effectively decrease the concentration of p-hydroxybenzoic acid (PHA), which is associated with the incidence rate of black rot (R2 = 0.890, p < 0.05). The sorption kinetics and isotherm of PHA sorption on biochar indicate that the coexistence of heterogeneous and monolayer sorption plays an important role in the adsorption process. Using Molecular dynamics (MD), Density functional theory (DFT) and Independent gradient model (IGM) analyses, we provide evidence that van der Waals force (vdW), π–π bonds and H-bonds between biochar and PHAs are the dominant factors that affect adsorption capacity. Moreover, the molecular adsorption rate (Nbiochar: NPHAs = 1:4) was theoretically calculated. In contrast, biochar dramatically increased nutrient retention capacity and improved soil properties, further enhancing tobacco quality, including its agronomic and physiological traits. Therefore, we considered that biochar not only relieved continuous cropping but also improved soil properties suitable for tobacco growth. Together, we demonstrate that the action of biochar in continuously cropped soil improves soil traits and alleviates auto-toxic compound toxicity. These data contribute to the direction of modified biochar application to improve continuous-cropping soil.

Ferroferric oxide (Fe3O4) magnetic nanoparticles are widely used as passive targeting carriers in gene therapy, due to their simple preparation, targeting under external magnetic field and easy surface grafting. This study synthesized oil phase Fe3O4 nanoparticles with controllable particle sizes in the range from 4 to 9 nm by regulating the accumulation growth time in the solvothermal method. Then, meso-2, 3-dimercaptosuccinic (DMSA) was employed to double exchange oleic acid molecules on its surface to provide good water dispersibility. Finally, Fe3O4-DMSA-PEI magnetic nanoparticles were obtained by grafting branched polyethylenimine (PEI) onto Fe3O4-DMSA surface through amidization reaction. The results demonstrate that the Fe3O4-DMSA-PEI magnetic nanoparticles have a surface Zeta potential of (52.50 +/- 1.94) mV, remaining a certain degree of superparamagnetism (14.48 emu/g, 1 emu/g=1 A center dot m(2)/kg). When the mass ratio of Fe3O4-DMSA-PEI magnetic nanoparticles to plasmid DNA is 15 : 1, it can completely block DNA and its loading capacity is as high as 6.67%. The Fe3O4-DMSA-PEI magnetic nanoparticles prepared in this study have a certain gene delivery ability and are expected to be used as gene carriers in the field of gene transfection.

Purpose The health of rhizosphere soil microorganisms is an important indicator to evaluate soil quality. Therefore, understanding the response of rhizosphere soil microorganisms to tobacco crop succession is crucial for promoting the sustainable development of agriculture. Methods The microbial diversity and community structure of rhizosphere soil in continuous cropping and non-cropped tobacco for 7 years were analyzed by the Illumina platform. Result (1) Continuous cropping tobacco cause rhizosphere soil acidification and reduction in alkaline nitrogen (AN) and soil organic matter (SOM). (2) Continuous cropping tobacco reduces the diversity of rhizosphere soil microbial communities, increasing harmful functional microorganisms and declining beneficial ones. (3) The abundance of bacteria that perform nitrification and saprophytic fungi in the rhizosphere soil of continuous cropping areas decreases, inhibiting carbon and nitrogen cycling processes. (4) The composition and diversity of the soil rhizosphere microbial community are affected by the imbalance in the physicochemical property of the rhizosphere. Conclusion Continuous cropping tobacco cause rhizosphere soil acidification and nutrient imbalance, and the carbon and nitrogen cycles involved in microorganisms were damaged. Furthermore, the decreased diversity of rhizosphere soil microorganisms and the increased abundance of pathogenic fungi contribute to the continuous cropping obstacles of tobacco.

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Gelatin was widely used as scaffold materials in 3D bio-printing due to its excellent bioactivity and availability and especially that their arginine–glycine–aspartic acid (RGD) sequences could efficiently promote cell adhesion and proliferation. In this study, an electroactive and 3D bio-printable hydrogel was prepared through a two-step chemical cross-linking process. Specifically, residual free amino groups of methacrylated gelatin (GelMA) were cross-linked with the aldehyde groups of dibenzaldehyde-terminated telechelic polyethylene glycol (DF-PEG) via Schiff base bonds, forming a gel at 37 °C. During the subsequent 3D bio-printing process, GelMA underwent UV curing, forming a secondary cross-linked network to the mechanical strength and stability of the printed structure. The uniform dispersion of carbon nanotubes (CNTs) in the GelMA/DF-PEG composite hydrogel significantly increased its conductivity. The optimized GelMA/DF-PEG composite hydrogel, i.e., 30% GelMA and 25% DF-PEG (G30D25-CNTs), exhibited superior bio-printability. When the content of CNTs was above 4%, the conductivity of G30D25-CNTs hydrogel exceeded 10 –2 S/m, which satisfied the needs of cells for micro-current stimulation. Furthermore, the pore microstructures, swelling behavior, degradation ability and cell toxicity of G30D25-CNTs electroactive hydrogels were thoroughly evaluated. Thus, the G30D25-CNTs hydrogel with 4% MWCNTs could be considered for further application in electrical stimulation of tissue regeneration such as muscle and cardiac nerve tissue repair.

Understanding the response of microbial communities and their potential functions is essential for sustainability of agroecosystems under long-term continuous cropping. However, limited research has focused on investigating the interaction between soil physicochemical factors and microbial community dynamics in agroecosystems under long-term continuous cropping. This study probed into the physicochemical properties, metabolites, and microbial diversity of tobacco rhizosphere soils cropped continuously for 0, 5, and 20 years. The relative abundance of bacterial genera associated with nutrient cycling (e.g., Sphingomonas) increased while potential plant pathogenic fungi and beneficial microorganisms showed synergistic increases with the duration of continuous cropping. Variations in soil pH, alkeline nitrogen (AN) content, and soil organic carbon (SOC) content drove the shifts in soil microbial composition. Metabolites such as palmitic acid, 3-hydroxypropionic acid, stearic acid, and hippuric acid may play a key role in soil acidification. Those results enhance our ability to predict shifts in soil microbial community structure associated with anthropogenic continuous cropping, which can have long-term implications for crop production.

Microplastics pollution in agricultural soil is increasingly recognized, but the specific situation varies with geography, climate conditions, and farming practices. The karst landscape, a typical geomorphology in China, demands a deeper understanding of microplastics pollution in such areas. This research zeroes in on Guizhou, a province known for its karst formations, by collecting soil samples from the mulched cultivation layer in ten counties and cities. The study employed metallographic microscopy, scanning electron microscopy (SEM-EDS), and Fourier-transform infrared spectroscopy (FT-IR) to analyze the presence and distribution of microplastics. Results show that polyethylene is the predominant component of microplastics in the mulched agricultural soils of Guizhou, primarily existing as irregular fragments in black, transparent, and translucent forms, with diameters of 40 similar to 120 mu m and rough surfaces marked by significant erosion. The concentration of microplastics varies from 143.28 to 3,283.46 items/kg, averaging 1,150.60 +/- 647.86 items/kg. The majority of particles accounting for 64.79% are sized between 10 similar to 100 mu m. A highly significant positive correlation (p < 0.001) is found between mulching duration and microplastics concentration, indicating that prolonged mulching increases microplastics accumulation in farmlands. Additionally, crop type, irrigation method, and soil type also influence microplastics concentration. This study highlights the escalating issue of microplastics pollution in China's karst regions, underscoring the need for attention.

Introduction:Biochar has been shown to be an effective soil amendment for promoting plant growth and improving nitrogen (N) utilization. However, the physiological and molecular mechanisms behind such stimulation remain unclear.Methods:In this study, we investigated whether biochar-extracted liquor including 21 organic molecules enhance the nitrogen use efficiency (NUE) of rice plants using two N forms (NH4 +-N and NO3 --N). A hydroponic experiment was conducted, and biochar-extracted liquor (between 1 and 3% by weight) was applied to rice seedlings.Results:The results showed that biochar-extracted liquor significantly improved phenotypic and physiological traits of rice seedlings. Biochar-extracted liquor dramatically upregulated the expression of rice N metabolism-related genes such as OsAMT1.1, OsGS1.1, and OsGS2. Rice seedlings preferentially absorbed NH4 +-N than NO3 --N (p < 0.05), and the uptake of NH4 +-N by rice seedlings was significantly increased by 33.60% under the treatment of biochar-extracted liquor. The results from molecular docking showed that OsAMT1.1protein can theoretically interact with 2-Acetyl-5-methylfuran, trans-2,4-Dimethylthiane, S, S-dioxide, 2,2-Diethylacetamide, and 1,2-Dimethylaziridine in the biochar-extracted liquor. These four organic compounds have similar biological function as the OsAMT1.1 protein ligand in driving NH4 +-N uptakes by rice plants.Discussion:This study highlights the importance of biochar-extracted liquor in promoting plant growth and NUE. The use of low doses of biochar-extracted liquor could be an important way to reduce N input in order to achieve the purpose of reducing fertilizer use and increasing efficiency in agricultural production.

Soil N plays a critical role in plant nutrition, which is controlled by nitrification. Biochar can enhance the N concentration of soil, which is thought to affect nitrification, especially when combined with chemical fertilizer (biochar fertilizer). However, there are several reports on biochar fertilizers that affect nitrifying communities. The related mechanism is also not understood. In this study, the nitrifying community analysis results suggested that the abundances of ammonia-oxidizing archaea in treatments BT3 and BT5 and ammonia-oxidizing bacteria (AOB) in treatment BT4 were significantly higher than those in other biochar fertilizer treatments, whereas nitrite-oxidizing bacteria (NOB) in treatment BT2 exhibited a more significant difference (p < 0.05). Compared with that in BT1, the AOB Nitrosomonas (51.74%) and NOB Nitrolancea (62.26%) became the dominant bacteria (p < 0.05) as the biochar fertilizer treatment increased. The metabolic composting and molecular docking theory precisely and simply illustrated that 2,2-diethylacetamide, which is similar to the oxalate ion, interacts with the active center of pyruvate kinase, which affects the glycolysis pathway. A potting experiment proved that the microbial composition originated from 2,2-diethylacetamide out of 17 biochar extracts, which increased pyruvate kinase gene expression from 1.37 to 11.03 (p < 0.05), pyruvic acid of pot soil from 1.73 to 21.65 (p < 0.05), and nitrifier abundance from 0.20% to 0.56% (p < 0.05). The soil Cu (R2 = 0.21; p < 0.05), Mo (R2 = 0.53; p < 0.05), Zn (R2 = 0.37; p < 0.05), and TOC (R2 = 0.24; p < 0.05) contents were negatively correlated with nitrifier abundance as the biochar fertilizer increased. Our study illuminates the mechanism of the effect of biochar and soil elements on the nitrifier community.

Based on bibliometric analysis, this paper summarized the research progress of the effects of biochar (BC) on soil physical and chemical properties and provided recommendations for future research. By using appropriate keywords, a total of 1,448 bibliographic records were retrieved from the Web of Science database, and these records were analysed on the basis of criteria, such as authors, keywords, citations, countries, institutions and journals. On the basis of these data, research advances were mapped to identify current scientific trends and the progress made, as well as knowledge gaps. The research began in the year 2010 and accelerated after the year 2015. Yong Sik Ok is the best-known and most productive author in the field. Moreover, China and America are important countries for BC research. Soil Biology and Biochemistry received the highest cocitation rate amongst active journals. Research hotspots can be separated into four distinct clusters, and future research can be summarised in these three directions: (1) the effects of BC mixed with organic and chemical fertilisers on crop growth and nitrogen use efficiency; (2) the response to a series of soil health problems, such as soil erosion and salinisation, by waste management to produce BC for bioremediation; and (3) the effects of BC on soil physicochemical properties from the perspective and mechanism of soil bacterial communities and other microorganisms.