Legumes are a vital component of agriculture, providing essential nutrients to both humans and soil through their ability to fix atmospheric nitrogen. However, the production of legume crops is often hindered by various biotic and abiotic stresses, limiting their yield and nutritional quality of crops by damaging plant tissues, which can result in lower protein content, reduced levels of essential vitamins and minerals, and compromised seed quality. This review discusses the recent advancements in technologies that are revolutionizing the field of legume crop improvement. Genetic engineering has played a pivotal role enhancing legume productivity. Through the introduction of genes encoding for enzymes involved in nitrogen fixation, leading to higher yields and reducing the reliance on synthetic fertilizers. Additionally, the incorporation of genes conferring disease and pest resistance has significantly reduced the need for chemical pesticides, making legume cultivation more sustainable and environmentally friendly. Genome editing technologies, such as CRISPR-Cas9, have opened new avenues for precision breeding in legumes. Marker-assisted selection and genomic selection are other powerful tools that have accelerated the breeding process. These techniques have significantly reduced time and resources required to develop new legume varieties. Finally, advancement technologies for legume crop improvement are aid and enhancing the sustainability, productivity, and nutritional quality of legume crops.

Moderate nitrogen addition can enhance plant growth performance under salt stress. However, the regulatory effects of nitrogen addition on the growth of the leguminous halophyte medicinal plant, Sophora alopecuroides, under salt stress remain unclear. In this study, a two-factor pot experiment with different NaCl levels (1 g/kg, 2 g/kg, 4 g/kg) and NH4NO3 levels (0 mg/kg, 32 mg/kg, 64 mg/kg, 128 mg/kg) was set up to systematically study the response of S. alopecuroides plant phenotype, nodulation and nitrogen fixation characteristics, nitrogen (N), phosphorus (P), potassium (K) nutrient absorption and utilization efficiency, plant biomass and nutrient accumulation to nitrogen addition under salt stress. The results demonstrated that under mild (1 g/kg NaCl) and moderate (2 g/kg NaCl) salt stress, S. alopecuroides exhibited a relatively low nitrogen demand. Specifically, low (32 mg/kg N) and medium (64 mg/kg N) nitrogen levels significantly enhanced nodule nitrogenase activity and nitrogen fixation capacity. Furthermore, the uptake of essential nutrients, including N, P, and K, in the aboveground biomass was markedly increased, which in turn promoted the accumulation of major nutrients such as crude protein, crude fat, and alkaloids, as well as overall biomass production. However, under severe (4 g/kg NaCl) salt stress, S. alopecuroides exhibited a preference for low nitrogen levels (32 mg/kg N). Under S3 conditions, excessive nitrogen application (e.g., 64 mg/kg and 128 mg/kg N) exacerbated the damage caused by salt stress, leading to significant inhibition of nitrogen fixation and nutrient uptake. Consequently, this resulted in a substantial reduction in biomass. This study provides a theoretical basis for nitrogen nutrition management of S. alopecuroides under salt stress conditions and offers valuable insights for optimizing fertilization and nutrient management strategies in saline-alkali agricultural production.

Periphyton-based biofertilizer have a high potential for soil remediation, particularly for controlling soil salinization. This global environmental problem leads to low soil utilization and insufficient crop yields. Efficient and sustainable methods of managing saline soils are needed to reduce salinization and improve soil fertility and crop quality. Traditional methods such as physical mulching and chemical amendments, while improving soil conditions, exhibit limited effectiveness and may damage soil structure. This study aims to evaluate the feasibility of algae-based fertilizers in remediating saline-alkali soils and improving crop performance. The review delves into the and application prospects of algae-based fertilizers, highlighting their potential from both sustainable development and economic perspectives. It further advocates integrating other emerging technologies with the production and application of algae-based fertilizers to address the increasingly severe challenges posed by degraded soil resources and environmental instability. The review found that algal fertilizers are more environmentally friendly than traditional chemical fertilizers but are not inferior in function. This approach offers more efficient and sustainable solutions for managing saline-alkaline soils and effectively achieves sus-tainable agricultural production. Furthermore, it is necessary to conduct experimental research and monitoring evaluations of algal fertilizers to formulate scientific and rational fertilization plans to meet the increasingly serious challenges facing soil resources and unstable environments. The findings of this study will provide theoretical and technical support for using algae biofertilizers for soil remediation, improving crop quality and sequestering carbon.

Highly saline soils negatively affect crop growth, especially rice. Although chemical approaches can be used, they damage the environment and the sustainability of the agriculture. Thus, a biological candidate should be assessed. Therefore, the study evaluated the impact of nitrogen (N)-fixing purple non-sulfur bacteria (PNSB) strains on improving soil properties, nutrient uptake, growth, and rice yield on highly saline soil in My Xuyen district, Soc Trang province. The N-fixing PNSB were hypothesized to boost soil nutrient availability and reduce soil salinity, leading to a greater rice growth and yield. A pot experiment was arranged in a completely randomized block design with two factors, including four N applying rates (100, 75, 50, and 0%) and N-fixing PNSB Rhodobacter sphaeroides (no added bacteria, single bacterial strain R. sphaeroides S01, single bacterial strain R. sphaeroides S06, and a mixture of two bacterial strains R. sphaeroides S01 and S06). The results showed that adding single strains S01, S06, and mixed strains S01 and S06 improved plant height by 4.02-10.4% (the first season) and 3.86-6.84% (the second season). Under the application of the mixture of two strains S01 and S06, the soil NH4 + increased by 31.8-50.5%, while the soil Na+ decreased by 16.0-25.7% in both seasons. From there, the total N uptake was also improved by 34.9-73.8% and the total Na uptake went down by 19.1-26.5% via two seasons. This led to greater rice growth and yield traits, such as the number of panicles per pot, the number of seeds per panicle, and the filled seed rate in both seasons. Ultimately, the rice grain yield was improved by 10.2-14.8% by the N-fixing PNSB under greenhouse condition. In conclusion, the current study successfully provided a potent N-fixer as a candidate for improvements of saline rice growth and soil health. Thus, this liquid biofertilizer should be further tested under field trails.

An Integrated Process Intensification (IPI) technology-based roadmap is proposed for the utilization of renewables (water, air and biomass/unavoidable waste) in the small-scale distributed production of the following primary products: electricity, H-2, NH3, HNO3 and symbiotic advanced (SX) fertilizers with CO2 mineralization capacity to achieve negative CO2 emission. Such a production platform is an integrated intensified biorefinery (IIBR), used as an alternative to large-scale centralized production which relies on green electricity and CCUS. Hence, the capacity and availability of the renewable biomass and unavoidable waste were examined. The critical elements of the IIBR include gasification/syngas production; syngas cleaning; electricity generation; and the conversion of clean syngas (which contains H-2, CO, CH4, CO2 and N-2) to the primary products using nonthermal plasma catalytic reactors with in situ NH3 sequestration for SA fertilizers. The status of these critical elements is critically reviewed with regard to their techno-economics and suitability for industrial applications. Using novel gasifiers powered by a combination of CO2, H2O and O-2-enhanced air as the oxidant, it is possible to obtain syngas with high H-2 concentration suitable for NH3 synthesis. Gasifier performances for syngas generation and cleaning, electricity production and emissions are evaluated and compared with gasifiers at 50 kWe and 1-2 MWe scales. The catalyst and plasma catalytic reactor systems for NH3 production with or without in situ reactive sequestration are considered in detail. The performance of the catalysts in different plasma reactions is widely different. The high intensity power (HIP) processing of perovskite (barium titanate) and unary/binary spinel oxide catalysts (or their combination) performs best in several syntheses, including NH3 production, NOx from air and fertigation fertilizers from plasma-activated water. These catalysts can be represented as BaTi1-vO3-x{#}(y)N-z (black, piezoelectric barium titanate, bp-{BTO}) and (M3-jMkO4-m)-M-(1)-O-(2){#}(n)N-r/SiO2 (unary (k = 0) or a binary (k > 0) silane-coated SiO2-supported spinel oxide catalyst, denoted as M/Si = X) where {#} infers oxygen vacancy. HIP processing in air causes oxygen vacancies, nitrogen substitution, the acquisition of piezoelectric state and porosity and chemical/morphological heterogeneity, all of which make the catalysts highly active. Their morphological evaluation indicates the generation of dust particles (leading to porogenesis), 2D-nano/micro plates and structured ribbons, leading to quantum effects under plasma catalytic synthesis, including the acquisition of high-energy particles from the plasma space to prevent product dissociation as a result of electron impact. M/Si = X (X > 1/2) and bp-{BTO} catalysts generate plasma under microwave irradiation (including pulsed microwave) and hence can be used in a packed bed mode in microwave plasma reactors with plasma on and within the pores of the catalyst. Such reactors are suitable for electric-powered small-scale industrial operations. When combined with the in situ reactive separation of NH3 in the so-called Multi-Reaction Zone Reactor using NH3 sequestration agents to create SA fertilizers, the techno-economics of the plasma catalytic synthesis of fertilizers become favorable due to the elimination of product separation costs and the quality of the SA fertilizers which act as an artificial root system. The SA fertilizers provide soil fertility, biodiversity, high yield, efficient water and nutrient use and carbon sequestration through mineralization. They can prevent environmental damage and help plants and crops to adapt to the emerging harsh environmental and climate conditions through the formation of artificial rhizosphere and rhizosheath. The functions of the SA fertilizers should be taken into account when comparing the techno-economics of SA fertilizers with current fertilizers.

Glacial retreat due to global warming is exposing large tracts of barren glacial sediments that are quickly colonized by CO2-fixing microbial communities that can constitute the climax community in many high-Arctic, alpine, and Antarctic environments. Despite the potential importance of these processes, little is known about microbial community successional dynamics and rates of carbon (C) sequestration in environments where higher plants are slow or unable to establish. We analyzed microbial community succession and C and N accumulation in newly exposed sediments along an Antarctic glacial chronosequence where moss and microbial autotrophs are the dominant primary producers. During the first 4 years of succession (0 to 40 m from the glacier) algae (including diatoms) were the most relatively abundant eukaryotes, but by the second phase studied (8 to 12 years) moss amplicon sequence variants (ASVs) dominated. The rise in moss coincided with a significant buildup of C and N in the sediments. The final two phases of the successional sequence (16 to 20 and 26 to 30 years) were marked by declines in microbial species richness and moss relative abundance, that coincided with significant decreases in both total C and N. These retrogressive declines coincided with a large increase in relative abundance of predatory Vampyrellidae suggesting a possible mechanism for retrogression in this and perhaps other terrestrial ecosystems at the edge of the cryosphere. These findings have implications for understanding CO2 sequestration and ecosystem succession in microbial-dominated regions of the cryobiosphere where large tracts of land are currently undergoing deglaciation.

The development of a nonconventional nitrogen fertilizer, which can be fixed in agricultural fields using decentralized renewable energy sources, presents a feasible solution for sustainable on-site nitrogen fixation and fertilization. This study focuses on plasma-generated dinitrogen pentoxide (N2O5) as a prospective mediator for the on-site nitrogen fertilization, allowing nitrogen fertilization directly into culture media. Basal dinitrogen pentoxide fertilization demonstrated almost 100% dinitrogen pentoxide dissolution efficiency as nitrate in a culture medium and nitrogen fertilization effect on plant growth without explicit symptoms of damage. Top-dressing of dinitrogen pentoxide was also an efficient method for transferring nitrogen into the soil as nitrate, which improved plant growth and suppressed nitrogen deficiency symptoms, while overdose caused adverse effects. Plants can be grown with dinitrogen pentoxide (N2O5), acting as a nitrogen fertilizer remotely synthesized from air by on-site plasma nitrogen fixation. Both basal N2O5 fertilization and top-dressing of N2O5 gas over soil significantly improved plant growth owing to high dissolution efficiency into liquid and soil. image

Mikania micrantha ( M. micrantha ), a plant species native to Central and South America, is one of the 100 most destructive invasive species. Its rapid growth and superior competitiveness compared to other plants cause significant damage to the natural ecosystem and result in substantial economic losses. Soil plays a crucial role as a medium for plants to obtain nutrients and to exchange substances with the environment. The presence of soil microorganisms is essential for plant survival and growth. Therefore, numerous studies have been carried out to investigate the changes in soil microbial structure and soil physical and chemical properties following M. micrantha invasion. Here, we reviewed recent research on soil microorganisms of M. micrantha from three perspectives: microbial diversity, abundance, and function. We summarized that the invasion of M. micrantha leads to an increase in microbial diversity, which ultimately benefits the plant growth. Furthermore, the changes in soil nutrients contribute to an increase in the density and abundance of the microbial population. This leads to an enrichment of biological control bacteria, which helps to suppress pathogenic bacteria in the rhizosphere of M. micrantha . Additionally, the soil associated with M. micrantha has a higher diversity and abundance of nitrogen -fixing bacteria, ammonifiers, phosphate-solubilizing bacteria, potassium-solubilizing bacteria, and other microorganisms. As a result, the efficiency of nitrogen fixation and ammonification are improved. This review not only provide valuable insights into the soil microorganisms associated with M. micrantha but also offer future research directions and the applicability of the knowledge gained.

Graphene quantum dots (GQDs) are useful nanomaterials of excellent water solubility, biocompatibility and optical stability for various applications. In this study, we achieved the nitrogen fixation activity enhancement of autogenous azotobacters (Azotobacter vinelandii) by GQDs and revealed its mechanism. GQDs (1-10 mg/L) accelerated the logarithmic growth phase of A. vinelandii, making bacteria enter the plateau earlier. Biocompatible GQDs did not cause cell death and oxidative damage of A. vinelandii. The expression levels of metabolism and nitrogen fixation related genes were significantly up-regulated by GQDs, thereby enhancing the activity of nitrogenase. The nitrogen fixation activity of A. vinelandii reached 471.7 % of the control upon the exposure to GQDs. The intracellular polyhydroxyalkanoate vesicles were consumed to provide energy for nitrogen fixation, which involved with a chain reaction of carbohydrate metabolism, lipid metabolism, and energy metabolism pathways accompanied by significant increases in electron transfer rate. The synergistic effect of GQDs on A. vinelandii further facilitated the augmentation of soil nitrogen content in Qinghai-Tibet Plateau. Our results provided an effective approach to enhance the biological nitrogen fixation by GQDs.

Biochar contains biotoxic aromatic compounds, and their influence on nitrogen-fixing cyanobacteria, the critical nitrogen fixer in paddy soil, has never been tested. Here, the physiological, metabolomic, and transcriptomic analyses of Nostoc sp. PCC7120 in response to biochar leachate were performed. The results suggested that biochar leachate inhibited the efficiency of photosynthesis, nitrogen fixation, and nitrate assimilation activities of nitrogen-fixing cyanobacteria. Biochar leachate containing aromatic compounds and odd- and long-chain saturated fatty acids impaired the membrane structure and antenna pigments, damaged the D1 protein of the oxygen evolution complex, and eventually decreased the electron transfer chain activity of photosystem II. Moreover, the nitrogen fixation and nitrate assimilation abilities of nitrogen-fixing cyanobacteria were inhibited Contents lists available at ScienceDirect Science of the Total Environment