Treatment of the saline-alkali soil with acidic corn stalk biochar and its effect on the sorghum yield in western Songnen Plain

Hydrothermal biochar enhances the photosynthetic efficiency and yield of alfalfa by optimizing soil chemical properties and stimulating the activity of microbial communities

Hydrothermal biochar has demonstrated potential in enhancing crop growth by improving soil properties and microbial activity; however, its effectiveness varies with application rate, with excessive amounts potentially inhibiting plant growth. This study employed a pot experiment approach to compare varying application rates of hydrothermal biochar (ranging from 0 to 50 t/ha) and to analyze its effects on alfalfa biomass, photosynthetic efficiency, soil nutrient content, and microbial community composition. Biochar application increased alfalfa dry weight by 12.22-21.20% in leaves, 31.60-55.60% in stalks, and 5.62-38.05% in roots. It also enhanced the light utilization efficiency of photosystem II. However, excessive biochar (50 t/ha) reduced biomass and photosynthesis. The addition of biochar amendments enhances soil nutrient availability, particularly increasing the accessibility of carbon, nitrogen, and phosphorus, while also lowering soil pH and enriching microbial interactions within bacterial communities. However, the effects on fungal communities are not pronounced. In conclusion, a moderate application of biochar (10-20t/ha) is recommended to maximize the growth of alfalfa and improve soil health, offering a practical approach for the sustainable cultivation of alfalfa.

Residual Effect of Microbial-Inoculated Biochar with Nitrogen on Rice Growth and Salinity Reduction in Paddy Soil

Increasing soil and water salinity threatens global agriculture, particularly affecting rice. This study investigated the residual effects of microbial biochar and nitrogen fertilizer in mitigating salt stress in paddy soil and regulating the biochemical characteristics of rice plants. Two rice varieties, Shuang Liang You 138 (SLY138), a salt-tolerant, and Jing Liang You 534 (JLY534), a salt-sensitive, were grown under 0.4 ds/m EC (S0) and 6.84 ds/m EC (S1) in a glass house under controlled conditions. Three types of biochar-rice straw biochar (BC), fungal biochar (BF), and bacterial biochar (BB)-were applied alongside two nitrogen (N) fertilizer rates (60 kg ha-1 and 120 kg ha-1) in a previous study. The required salinity levels were maintained in respective pots through the application of saline irrigation water. Results showed that residual effects of microbial biochars (BF and BB) had higher salt mitigation efficiency than sole BC. The combination of BB and N fertilizer (BB + N120) significantly decreased soil pH by 23.45% and Na+ levels by 46.85%, creating a more conducive environment for rice growth by enhancing beneficial microbial abundance and decreasing pathogenic fungi in saline soil. Microbial biochars (BF and BB) positively improved soil properties (physicochemical) and biochemical and physiological properties of plants, ultimately rice growth. SLY138 significantly had a less severe response to salt stress compared to JLY534. The mitigation effects of BB + N120 kg ha-1 were particularly favorable for SLY138. In summary, the combined residual effect of BF and BB with N120 kg ha-1, especially bacterial biochar (BB), played a positive role in alleviating salt stress on rice growth, suggesting its potential utility for enhancing rice yield in paddy fields.

Isolation, identification, and mechanism analysis of plant growth-promoting rhizobacteria in tobacco

Plant growth, crop yield, and pest and disease control are enhanced by PGPR (Plant growth promoting rhizobacteria), which are beneficial microorganisms found in a close symbiosis with plant roots. Phytohormones are secreted, nutrient uptake is improved, and soil properties along with the microbiological environment are regulated by these microorganisms, making them a significant focus in agricultural research. In this study, the efficient PGPR strain T1 was isolated and screened from tobacco inter-root soil, and identified and confirmed by ITS sequencing technology. Tobacco growth indicators and soil property changes were observed and recorded through potting experiments. The activities of key enzymes (e.g., sucrase, catalase, urease) in soil were further determined. High-throughput sequencing technology was utilized to sequence the soil microbial community, and combined with macro-genomics analysis, the effects of T1 strain on soil microbial diversity and metabolic pathways were explored. Following the application of T1, significant improvements were observed in the height, leaf length, and width of tobacco plants. Furthermore, the physical and chemical properties of the soil were notably enhanced, including a 26.26% increase in phosphorus availability. Additionally, the activities of key soil enzymes such as sucrase, catalase, and urease were significantly increased, indicating improved soil health and fertility. Comprehensive joint microbiomics and macrogenomics analyses revealed a substantial rise in the populations of beneficial soil microorganisms and an enhancement in metabolic pathways, including amino acid metabolism, synthesis, and production of secondary metabolites. These increase in beneficial microorganisms and the enhancement of their metabolic functions are crucial for plant growth and soil fertility. This study provides valuable references for the development of innovative microbial fertilizers and offers programs for the sustainable development of modern agriculture.

Exogenous Melatonin Alleviates NaCl Injury by Influencing Stomatal Morphology, Photosynthetic Performance, and Antioxidant Balance in Maize

Maize (Zea mays L.) is sensitive to salt stress, especially during seed germination and seedling morphogenesis, which limits maize growth and productivity formation. As a novel recognized plant hormone, melatonin (MT) participates in multiple growth and developmental processes and mediates biotic/abiotic stress responses, yet the effects of salt stress on maize seedlings remain unclear. Herein, we investigated the effects of 150 μM exogenous MT on multiple phenotypes and physiologic metabolisms in three-leaf seedlings across eight maize inbred lines under 180 mM NaCl salt stress, including growth parameters, stomatal morphology, photosynthetic metabolisms, antioxidant enzyme activities, and reactive oxygen species (ROS). Meanwhile, the six gene expression levels controlling antioxidant enzyme activities and photosynthetic pigment biosynthesis in two materials with contrasting salt resistance were examined for all treatments to explore the possible molecular mechanism of exogenous MT alleviating salt injury in maize. The results showed that 150 μM exogenous MT application protected membrane integrity and reduced ROS accumulation by activating the antioxidant system in leaves of maize seedlings under salt stress, their relative conductivity and H2O2 level average reduced by 20.91% and 17.22%, while the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) averaged increased by 13.90%, 17.02%, 22.00%, and 14.24% relative to salt stress alone. The improvement of stomatal size and the deposition of photosynthetic pigments were more favorable to enhancing photosynthesis in leaves when these seedlings treated with MT application under salt stress, their stomatal size, chlorophyll content, and net photosynthetic rate averaged increased by 11.60%, 19.64%, and 27.62%. Additionally, Gene expression analysis showed that MT stimulation significantly increased the expression of antioxidant enzyme genes (Zm00001d009990, Zm00001d047479, Zm00001d014848, and Zm00001d007234) and photosynthetic pigment biosynthesis genes (Zm00001d011819 and Zm00001d017766) under salt stress. At the same time, 150 μM MT significantly promoted seedling growth and biomass accumulation. In conclusion, our study may unravel crucial evidence of the role of MT in maize seedlings against salt stress, which can provide a novel strategy for improving maize salt stress resistance.

Enhancing salt tolerance and crop growth in agricultural systems: the impact of magnetized-ionized water irrigation on soil properties, microbial communities, and cotton growth

BACKGROUND

The development of agricultural practices requires an understanding of the improvement of salt tolerance and crop growth in agricultural systems through magnetized-ionized water irrigation.

METHOD

This study examined the impacts of fresh water (F), brackish water (B), magnetized-ionized fresh water (MIF), and magnetized-ionized brackish water (MIB) on soil properties and the growth of cotton seedlings through microbial analysis during the cotton seedling period.

RESULTS

The results revealed that magnetized-ionized water irrigation improved soil water retention and promoted salt leaching. In comparison with F irrigation, plant height, leaf area index (LAI), dry matter accumulation (DM), and chlorophyll content (SPAD) levels increased by 3.61%, 4.07%, 5.76%, and 1.33%, respectively, under MIF irrigation. Similarly, when compared with B irrigation, LAI, DM, and SPAD increased by 5.13%, 6.12%, and 3.12% under MIB irrigation. Magnetized-ionized water irrigation also led to a notable rise in the relative abundance of beneficial soil bacterial communities, particularly Pseudomonas and Azoarcus, as well as fungal communities like Trichoderma, while reducing the prevalence of pathogenic fungi, such as Lasionectria, Gibberella, and Alternaria. Notably, this irrigation approach induced alterations in soil properties, and partial least squares path modeling revealed significant links between soil properties and both cotton growth and fungal community structure (with path coefficients of -0.884 and 0.693, respectively).

CONCLUSION

This study elucidated the distinct effects of soil properties and growth indices on cotton yield during the seedling period, providing a crucial scientific foundation for enhancing future agricultural production through the use of magnetized-ionized water irrigation. © 2024 Society of Chemical Industry.

The mechanism of using magnetized-ionized water in combination with organic fertilizer to enhance soil health and cotton yield

Addressing critical challenges in sustainable agriculture, notably water scarcity and soil degradation, necessitates innovative irrigation and fertilization methods. This investigation thoroughly assessed the effects of combining inorganic and organic fertilizers under brackish water irrigation, particularly focusing on magnetized-ionized brackish water-a promising solution for these challenges. The study shows that the integration of inorganic and organic fertilizers notably enhances soil water retention and salt leaching when applied with magnetized-ionized brackish water irrigation (MIBIO treatment), with water storage rate and salt accumulation rate observed at -0.454 and -0.075, respectively. Additionally, soil microbial diversity and uniformity witnessed significant improvement, positively influencing cotton growth rates, particularly noting a dry matter accumulation rate of 9.3262 kg·(ha·°C)-1. Transcriptomic analysis revealed that the MIBIO treatment elevated gene expression during the boll period, with notable enrichment in pathways such as the MAPK signaling pathway-plant and amino sugar and nucleotide sugar metabolism. Furthermore, the partial least squares path modeling indicated that soil alkali-hydrolyzed nitrogen (AN) and available potassium (AK) positively impact cotton leaf transcription and yield, with path coefficients of 0.613 and 0.428, respectively. Specifically, AN and AK contribute to enhancing cotton growth and affect the expression of metabolism genes in cotton leaves, thereby increasing cotton yield. Our study highlights the crucial role of irrigation and fertilization in influencing the soil environment and cotton growth. We recommend the use of magnetized-ionized water irrigation in combination with organic fertilizers as a strategy to boost agricultural productivity. Through the development of these strategies, our goal is to offer farmers practical guidance that can be readily implemented to enhance crop production efficiency, reduce environmental impact, and adhere to the principles of sustainable agriculture.

Assessing the efficacy of natural soil biotin on soil quality, microbial diversity, and Rhododendron simsii growth for sustainable landscape architecture

Fertilization significantly influences soil quality and its sustainable use in urban garden maintenance. The widespread application of inorganic fertilizers has raised ecological concerns due to their potential environmental impacts. Organic fertilizers, while beneficial, often have slow effects and are costly. Biofertilizers, with their eco-friendly nature and low carbon footprint, are gaining attention for their multifaceted role in supporting plant growth. Despite the focus on fruit trees, vegetables, and medicinal plants, ornamental plants have been understudied. This study aims to evaluate the efficacy of a novel microbial fertilizer, 'natural soil biotin', on Rhododendron plants, specifically the Azalea hybrid 'Carnation'. The study employed a comparative approach to assess the impact of different fertilization strategies on soil properties, microbial diversity, enzyme activity, plant morphology, and physiological parameters. The application of 'natural soil biotin' was compared with the use of inorganic and organic fertilizers. The combined application of 'natural soil biotin' was found to effectively enhance soil properties and mitigate the impact of other fertilizers on soil pH. It also improved the relative abundance of beneficial microbial groups such as Proteobacteria, Ascomycota, and Basidiomycota. Furthermore, the mixed application significantly increased the activities of urease and sucrase in Rhododendron plants, which promoted their growth, development, and stress resistance. The results indicate that the mixed application of 'natural soil biotin' with inorganic and organic fertilizers not only improved the soil quality but also enhanced the efficiency of fertilizer utilization. This approach led to increased economic and environmental benefits in Rhododendron cultivation. The findings contribute to the foundation for soil improvement and ecological restoration, suggesting that 'natural soil biotin' could be a promising alternative or supplement to traditional fertilization methods in sustainable landscape architecture.

Analysis of widely targeted metabolites of quinoa sprouts (Chenopodium quinoa Willd.) under saline-alkali stress provides new insights into nutritional value

Quinoa sprouts are a green vegetable rich in bioactive chemicals, which have multiple health benefits. However, there is limited information on the overall metabolic profiles of quinoa sprouts and the metabolite changes caused by saline-alkali stress. Here, a UHPLC-MS/MS-based widely targeted metabolomics technique was performed to comprehensively evaluate the metabolic profiles of quinoa sprouts and characterize its metabolic response to saline-alkali stress. A total of 930 metabolites were identified of which 232 showed significant response to saline-alkali stress. The contents of lipids and amino acids were significantly increased, while the contents of flavonoids and phenolic acids were significantly reduced under saline-alkali stress. Moreover, the antioxidant activities of quinoa sprouts were significantly affected by saline-alkali stress. The enrichment analysis of the differentially accumulated metabolites revealed that flavonoid, amino acid and carbohydrate biosynthesis/metabolism pathways responded to saline-alkali stress. This study provided an important theoretical basis for evaluating the nutritional value of quinoa sprouts and the changes in metabolites in response to saline-alkali stress.

Salt-tolerant plant growth-promoting bacteria as a versatile tool for combating salt stress in crop plants

Soil salinization poses a great threat to global agricultural ecosystems, and finding ways to improve the soils affected by salt and maintain soil health and sustainable productivity has become a major challenge. Various physical, chemical and biological approaches are being evaluated to address this escalating environmental issue. Among them, fully utilizing salt-tolerant plant growth-promoting bacteria (PGPB) has been labeled as a potential strategy to alleviate salt stress, since they can not only adapt well to saline soil environments but also enhance soil fertility and plant development under saline conditions. In the last few years, an increasing number of salt-tolerant PGPB have been excavated from specific ecological niches, and various mechanisms mediated by such bacterial strains, including but not limited to siderophore production, nitrogen fixation, enhanced nutrient availability, and phytohormone modulation, have been intensively studied to develop microbial inoculants in agriculture. This review outlines the positive impacts and growth-promoting mechanisms of a variety of salt-tolerant PGPB and opens up new avenues to commercialize cultivable microbes and reduce the detrimental impacts of salt stress on plant growth. Furthermore, considering the practical limitations of salt-tolerant PGPB in the implementation and potential integration of advanced biological techniques in salt-tolerant PGPB to enhance their effectiveness in promoting sustainable agriculture under salt stress are also accentuated.

Soil amendments reduce CH4 and CO2 but increase N2O and NH3 emissions in saline-alkali paddy fields

Limited research has been conducted on ammonia (NH3) volatilization and greenhouse gases (GHGs) emissions in saline-alkali paddy fields, along with complex interaction involving various genes (16sRNA, amoA, narG, nirK, nosZ, and nifH). This study employed mesocosm-scale experiment to investigate NH3 volatilization and GHGs emissions, focusing on bacterial communities and genic abundance, in saline-alkali paddy fields with desulfurized gypsum (DG) and organic fertilizer (OF) amendments. Compared to the control (CK) treatment, DG and OF treatments reduced methane (CH4) and carbon dioxide (CO2) emissions by 78.05 % and 26.18 %, and 65.84 % and 11.62 %, respectively. However, these treatments increased NH3 volatilization by 26.26 % and 45.23 %, and nitrous oxide (N2O) emission by 41.00 % and 12.31 %. Notably, NH3 volatilization primarily stemmed from ammonia nitrogen (NH4+-N), rather than total nitrogen (TN) in soil and water. N2O was mainly produced from nitrate nitrogen (NO3--N) in soil and water, as well as NH4+-N in water. The increase in NH3 volatilization and N2O emission in DG and OF treatments, was attributed to the reduced competition among bacterial communities, rather than the increased bacterial activity and genic copies. These findings offer valuable insights for managing nutrient loss and gaseous emissions in saline-alkali paddy fields.

The effect of modifier and a water-soluble fertilizer on two forages grown in saline-alkaline soil

Saline-alkali soil significantly impairs crop growth. This research employs the impacts of the modifier and water-soluble fertilizer, as well as their interaction, on the root systems of alfalfa and leymus chinensis in saline-alkali soil. The results exhibit that the hydrochar source modifier effectively enhances the root growth of both forage species. There are certain improvements in the root growth indicators of both crops at a dosage of 20 g/kg. Root enzyme activity and rhizosphere soil enzyme activity are enhanced in alfalfa, showing significant improvements in the first planting compared to the second planting. The application of water-soluble fertilizers also promotes root growth and root dehydrogenase activity. The root dehydrogenase activity of alfalfa and leymus chinensis are enhanced 62.18% and 10.15% in first planting than that of blank, respectively. Additionally, the two-factor variance analysis revealed a correlation between rhizosphere soil enzyme activity and changes in root traits. Higher rhizosphere soil enzyme activity is observed in conjunction with better root growth. The combined application of a modifier and water-soluble fertilizer has demonstrated a significant interaction effect on various aspects of the first planting of alfalfa and leymus chinensis. Moreover, the combined application of the modifier and water-soluble fertilizer has yielded superior results when compared to the individual application of either the modifier or the water-soluble fertilizer alone. This combined approach has proven effective in improving saline-alkali soil conditions and promoting crop growth in such challenging environments.

Evaluation of net carbon sequestration and ecological benefits from single biochar-incorporated sorghum farmland systems in saline-alkali areas of Inner Mongolia, China

Biochar is widely recognized as a soil amendment to reduce greenhouse gas emissions and enhance soil carbon storage in agroecosystems; however, the systematic focus on carbon balance and ecological benefits in cropping systems remains unclear in saline-alkali areas under water-saving irrigation. Here, a 2-yr field experiment with carbon footprint method was conducted to determine soil carbon budgets, biochar carbon efficiency performance, and the economic and ecological benefits of mulched drip-irrigated sorghum production, in an arid salinized region of Inner Mongolia, China. Corn straw-derived biochar dosages of 0 (CK), 15 (B15), 30 (B30), and 45 (B45) t hm-2 were just applied into the soil in the first crop growing season. A single application of biochar to soil significantly reduced CO2 emissions for the current and subsequent crop-growing seasons, with 13.1%, 16.7%, and 12.5% reductions for B15, B30, and B45, respectively. Compared with the non-biochar control plots, B15, B30, and B45 also increased NPP by 36.7%, 38.4%, and 27.1%, respectively. The actual effects on improving net carbon sequestration for B15, B30, and B45 in the first year were higher than those in the second year, with mean increases of 1.27, 1.47, and 1.36 times, respectively; however, the efficiencies of biochar for fixing carbon per biochar dosage input for B15 were 72.8% and 64.1% higher than those of B30 and B45, respectively. Net profits were significantly improved by 57.2-87.1% by biochar treatments. The environmental benefits of biochar carbon trading revenues for B15, B30, and B45 increased by 105.9%, 162.1%, and 109.6%, respectively. The minimum observation for carbon productivity and the maximum measurements for both the economic and ecological benefits were B15. The B15 also significantly increased sorghum yield and grain number. Results demonstrate that biochar application in the current growing season helps reduce soil carbon emissions, increases net carbon sequestration for current and subsequent sorghum agroecosystems, and enhances net profit and ecological benefits. The optimal positive synergistic effect was observed at a biochar application rate of 15 t hm-2 for reducing soil carbon emissions, increasing crop production, and improving the ecological environment.

Biochar Decreases Fertilizer Leaching and Promotes Miscanthus Growth in Saline-Alkaline Soil

Biochar has been widely reported to improve soil conditions and affect plant growth. However, its effectiveness is limited by soil type and production technology. Considering the application effect of biochar in saline alkali soil, there is currently a lack of in-depth mechanism explanations in the research. Therefore, we designed an experiment to explore the effect of biochar on plant growth in saline alkali soil and conducted soil column experiments in a greenhouse environment using composite inorganic fertilizer (NPK). The results showed that biochar significantly affected the distribution of soil nutrient content at different depths, with a significant increase in fertility levels in the surface and middle layers and a decrease in fertility levels in deep soils. Compared to using fertilizers alone, the combined use of biochar and fertilizers further expands the enrichment effect and significantly reduces the leaching of fertilizers into deeper layers. At the same time, the application of biochar also improved soil properties, including an increase in electrical conductivity and organic matter content, as well as an increase in soil enzyme activity. On the other hand, the application of biochar also increases the activity of antioxidant enzymes and the content of osmoregulation substances in plants, reducing the environmental stress that plants are subjected to. Therefore, our results indicate that biochar can reduce the leaching of fertilizers into deep soil layers, improve soil properties, and promotes the growth of Miscanthus in saline alkali soils.

Biochar as a carbonaceous material to enhance soil quality in drylands ecosystems: A review

Drylands are fragile environments that should be carefully managed to improve their quality and functions to achieve sustainable development. Their major problems involve low availability of nutrients and soil organic carbon content. Biochar effect on soil is a joint response of micro to nano sized biochar and soil characteristics. In this review, we attempt to carry out a critical analysis of biochar application to enhance dryland soil quality. Correlating the effects identified from its soil application, we explored the subjects that remains open in the literature. The relation of composition-structure-properties of biochar vary among pyrolysis parameters and biomass sources. Limitations in soil physical quality in drylands, such as low water-holding capacity, can be alleviated by applying biochar at a rate of 10 Mg ha-1 also resulting in beneficial effects on soil aggregation, improved soil porosity, and reduced bulk density. Biochar addition can contribute to the rehabilitation of saline soils, by releasing cations able to displaces sodium in the exchange complex. However, the recovery process of salt-affected soils might be accelerated by the association of biochar with another soil conditioners. This is a promising strategy especially considering the biochar alkalinity and variability in nutrients bioavailability to improve soil fertilization. Further, while higher biochar application rate (>20 Mg ha-1) might change soil C dynamics, a combination of biochar and nitrogen fertilizer can increase microbial biomass carbon in dryland systems. Other aspect of biochar soil application is the economic viability of scale-up production, which is mainly associate to pyrolysis process being biochar production the costliest stage. Nevertheless, the supplying of feedstock might also represent a great input on biochar final costs. Therefore, biochar-based technology is a big opportunity to improve fragile environments such as drylands, integrating sustainable technologies with regional development. Considering the specificity of application area, it might be a model of sustainable agricultural practices protecting the environment in a bioeconomic perspective.

Liquid-solid ratio during hydrothermal carbonization affects hydrochar application potential in soil: Based on characteristics comparison and economic benefit analysis

Returning straw-like agricultural waste to the field by converting it into hydrochar through hydrothermal carbonization (HTC) is an important way to realize resource utilization of waste, soil improvement, and carbon sequestration. However, the large-scale HTC is highly limited by the large water consumption and waste liquid pollution. Here, we propose strategies to optimize the liquid-solid ratio (LSR) of HTC, and comprehensively evaluate the stability, soil application potential, and economic benefits of corn stover-based hydrochar under different LSRs. The results showed that the total amount of dissolved organic carbon of hydrochars increased by 55.0% as LSR reducing from 10:1 to 2:1, while the element content, thermal stability, carbon fixation potential, specific surface area, pore volume, and functional group type were not obviously affected. The specific surface area and pore volume of hydrochar decreased by 61.8% and 70.9% as LSR reduced to 1:1, due to incomplete carbonization. According to the gray relation, hydrochar derived at LSR of 10:1 and followed by 2:1 showed greatest relation degree of 0.80 and 0.70, respectively, indicating better soil application potential. However, reducing LSR from 10:1 to 2:1 made the income of single process production increased from -388 to 968 ¥, and the wastewater generation decreased by 80%. Considering the large-scale application of HTC in fields for farmland improvement and environmental remediation, the comprehensive advantages of optimized LSR will be further highlighted.

Biochar Promotes Arsenopyrite Weathering in Simulated Alkaline Soils: Electrochemical Mechanism and Environmental Implications

Oxidation dissolution of arsenopyrite (FeAsS) is one of the important sources of arsenic contamination in soil and groundwater. Biochar, a commonly used soil amendment and environmental remediation agent, is widespread in ecosystems, where it participates in and influences the redox-active geochemical processes of sulfide minerals associated with arsenic and iron. This study investigated the critical role of biochar on the oxidation process of arsenopyrite in simulated alkaline soil solutions by a combination of electrochemical techniques, immersion tests, and solid characterizations. Polarization curves indicated that the elevated temperature (5-45 °C) and biochar concentration (0-1.2 g·L^-1) accelerated arsenopyrite oxidation. This is further confirmed by electrochemical impedance spectroscopy, which showed that biochar substantially reduced the charge transfer resistance in the double layer, resulting in smaller activation energy (E_a = 37.38-29.56 kJ·mol^-1) and activation enthalpy (ΔH* = 34.91-27.09 kJ·mol^-1). These observations are likely attributed to the abundance of aromatic and quinoid groups in biochar, which could reduce Fe(III) and As(V) as well as adsorb or complex with Fe(III). This hinders the formation of passivation films consisting of iron arsenate and iron (oxyhydr)oxide. Further observation found that the presence of biochar exacerbates acidic drainage and arsenic contamination in areas containing arsenopyrite. This study highlighted the possible negative impact of biochar on soil and water, suggesting that the different physicochemical properties of biochar produced from different feedstock and under different pyrolysis conditions should be taken into account before large-scale applications to prevent potential risks to ecology and agriculture.

Integrated microbiological and metabolomics analyses to understand the mechanism that allows modified biochar to affect the alkalinity of saline soil and winter wheat growth

In order to understand the mechanism that allows modified biochar (BC) to enhance the salt tolerance and growth of crops in saline-alkali soil, we tested the effects of ordinary BC, nanoparticle-size BC, acidified BC (HBC), and acidified nanoparticle-size BC on winter wheat growth and the soil properties by combining microbiological and metabolomics analyses. The results showed that compared with the control with no BC, the plant height increased by 17.33 % under HBC and the proportion of large soil aggregates increased by 1.25-2.83 times. HBC increased the relative abundances of some dominant genera of bacteria (e.g., Streptococcus) and fungi (e.g., Mycothermus), as well as functions such as bacterial metabolic genetic information processing and cellular processes, and reduced the abundance of pathotrophic fungi. Metabolomics analysis showed that HBC upregulated various metabolites (including amino acids and their derivatives, lipids, flavonoids, and organic acids) and five main metabolic pathways. Among the KEGG pathways, the pyrimidine metabolism pathway was significantly upregulated, as well as crop leaf metabolism, β-alanine metabolism, and valine, leucine, and isoleucine metabolism, and the antioxidant levels and resistance to salt-alkali stress were enhanced in winter wheat leaves. Partial least squares-path modeling suggested that HBC affected the growth of winter wheat by significantly changing the soil physicochemical properties and microbial structure (path coefficients of 0.566 and 0.512, respectively).

Responses of Soil Collembolans to Land Degradation in a Black Soil Region in China

Land degradation in black soil regions has a significant effect on belowground systems, and Collembolans can adequately indicate environmental changes in the soil. However, there is currently a knowledge gap in the literature regarding the responses of soil Collembolans to land degradation. In order to better understand this issue, in this study, a total of 180 soil Collembolan samples were collected from four habitats with varying degrees of land degradation in the Songnen Plain, namely a no land-degradation habitat (NLD), light land-degradation habitat (LLD), moderate land-degradation habitat (MLD) and severe land-degradation habitat (SLD). The results reveal that the different degrees of land degradation caused some differences in the taxonomic composition of the Collembolans; however, the majority of the Collembolan species are distributed relatively evenly. Proisotoma minima are always a dominant species during the study period. Seasonal variations are observed in the abundance, richness and diversity levels. In the severe land-degradation habitats (SLD), the abundance, richness, diversity and community complexity of the Collembolans are aways at the lowest levels. In addition, Proisotoma minima is negatively correlated with a majority of the species of Collembolans in the low levels of the land-degradation habitats, whereas they are positively correlated with most of the other species in the high levels. Epedaphic and euedaphic Collembolans responded to land degradation more obviously. The structural equation model (SEM) displays that soil Collembolan communities respond negatively to land degradation. Overall, our results provide implications that soil Collembolan communities are affected by land degradation, and that different taxa of soil Collembolans respond to degradation in numerous ways.

Carbon Amendments Shape the Bacterial Community Structure in Salinized Farmland Soil

Practical, effective, and economically feasible salt reclamation and amelioration methods are in great demand in arid and semiarid areas. Energy amendments may be more appropriate than alternatives for improving salinized farmland soil because of their effects on soil microbes. We investigated the effects of biochar (Carbon) addition and desulfurization (noncarbon) on the soil bacterial community associated with Zea mays seedlings. Proteobacteria, Firmicutes, and Actinobacteriota were the dominant soil bacterial phyla. Biochar significantly increased soil bacterial biodiversity but desulfurization did not. The application of both amendments stimulated a soil bacterial community shift, and biochar amendments relieved selection pressure and increased the stochasticity of community assembly of bacterial communities. We concluded that biochar amendment can improve plant salt resistance by increasing the abundance of bacteria associated with photosynthetic processes and alter bacterial species involved in carbon cycle functions to reduce the toxicity of soil salinity to plants. IMPORTANCE Farmland application of soil amendments is a usual method to mitigate soil salinization. Most studies have concluded that soil properties can be improved by soil amendment, which indirectly affects the soil microbial community structures. In this study, we applied carbon and noncarbon soil amendments and analyzed the differences between them on the soil microbial community. We found that carbon soil amendment distinctly altered the soil microbial community. This finding provides key theoretical and technical support for using soil amendments in the future.

Biochar improves soil quality and wheat yield in saline-alkali soils beyond organic fertilizer in a 3-year field trial

The objective of this study was to examine the effects of biochar compared to organic fertilizer on soil quality and wheat yield in the saline-alkaline lands. A 3-year field trial was conducted on moderately saline-alkaline land in the Yellow River Delta region (YRD) with six treatments: biochar (B1: 5 t, B2: 10 t, B3: 20 t ha^-1 year^-1) and organic fertilizer (OF1: 5 t, OF2: 7.5 t ha^-1 year^-1) as well as control (CK). The results showed that both biochar and organic fertilizer increased total organic carbon (TOC), total nitrogen (TN), NH₄⁺-N, and NO₃^--N, and reduced pH, thereby increasing soil microbial biomass carbon (MBC) and nitrogen (MBN), MBC/TOC ratio, and MBN/TN ratio, but organic fertilizer increased soil nutrients and microbial biomass better than biochar. Correlation analysis revealed that soil water content (SWC), soil salt content (SSC), and Na⁺ were the most important factors influencing wheat yield. When compared to CK, the SSC and Na⁺ decreased by 5.55-7.52% and 3.86-9.39%, respectively, and SWC increased by 5.14-5.62% in the biochar treatment, while they increased by 1.07-10.19%, 1.08-7.58%, and 2.96-3.84% in the organic fertilizer treatment, respectively. Accordingly, wheat yield of biochar treatment was 0.90-14.71% higher than that of organic fertilizer treatment (4.49-4.80 t ha^-1) and CK (4.47 t ha^-1). Collectively, B2 had the lowest SSC and Na⁺ and the highest yield and was significantly better than the organic fertilizer treatment, as well as efficiently increasing soil nutrients and microbial biomass, suggesting that it may be a better agricultural practice for improving soil quality and increasing wheat yield in the YRD.

Advances and future research in ecological stoichiometry under saline-alkali stress

Saline-alkali stress is a serious abiotic factor which negatively impacts agricultural production and the ecological environment. Thus, improving the development of saline-alkali soil and reducing the effects of saline-alkali stress is a key issue for sustainable agricultural development and environmental protection. As such, it is unsurprising that researchers have lately focused on how to improve saline-alkali soil, increase the agricultural yield of saline-alkali land, and promote the adaptive growth of plants in saline-alkali soil. This paper reviews the latest research concerning nutrient content changes in saline-alkali soil, along with the associated changes in key nutrients in plants, to summarize which methods are most effective for improving the plant growth under saline-alkali stress. Finally, the prospects for alleviating saline-alkali stress and improving saline-alkali soil are put forward as a theoretical foundation for the stabilization of plant growth in saline-alkali soil, expansion of arable land area, crop yield improvement, and effective environmental protection.

Schiff Base Aggregation-Induced Emission Luminogens for Sensing Applications: A Review

Fluorescence sensing can not only identify a target substrate qualitatively but also achieve the purpose of quantitative detection through the change of the fluorescence signal. It has the advantages of immense sensitivity, rapid response, and excellent selectivity. The proposed aggregation-induced emission (AIE) concept solves the problem of the fluorescence of traditional fluorescent molecules becoming weak or quenched in high concentration or aggregated state conditions. Schiff base fluorescent probes have the advantages of simple synthesis, low toxicity, and easy design. They are often used for the detection of various substances. In this review we cover late developments in Schiff base compounds with AIE characteristics working as fluorescence sensors.

Metabolic differences of two constructive species in saline-alkali grassland in China

BACKGROUND

Salinization of soil is an urgent problem that restricts agroforestry production and environmental protection. Substantial accumulation of metal ions or highly alkaline soil alters plant metabolites and may even cause plant death. To explore the differences in the response strategies between Suaeda salsa (S. salsa) and Puccinellia tenuiflora (P. tenuiflora), two main constructive species that survive in saline-alkali soil, their metabolic differences were characterized.

RESULT

Metabolomics was conducted to study the role of metabolic differences between S. salsa and P. tenuiflora under saline-alkali stress. A total of 68 significantly different metabolites were identified by GC-MS, including 9 sugars, 13 amino acids, 8 alcohols, and 34 acids. A more detailed analysis indicated that P. tenuiflora utilizes sugars more effectively and may be saline-alkali tolerant via sugar consumption, while S. salsa utilizes mainly amino acids, alcohols, and acids to resist saline-alkali stress. Measurement of phenolic compounds showed that more C6C3C6-compounds accumulated in P. tenuiflora, while more C6C1-compounds, phenolic compounds that can be used as signalling molecules to defend against stress, accumulated in S. salsa.

CONCLUSIONS

Our observations suggest that S. salsa resists the toxicity of saline-alkali stress using aboveground organs and that P. tenuiflora eliminates this toxicity via roots. S. salsa has a stronger habitat transformation ability and can provide better habitat for other plants.