The application of coating materials to regulate nitrogen release is a crucial strategy for minimizing fertilizer loss and alleviating agricultural nitrogen pollution. However, it remains a significant challenge to develop ecofriendly coatings that are both biodegradable and effective in slow-release. In this study, Ca/Al layered double hydroxides (LDHs) were incorporated into a conventional polyvinyl alcohol/polyvinylpyrrolidone (PVA/ PVP) matrix to create PVA/PVP-LDHs composite films. The inclusion of LDHs (1.0 %, w/w) resulted in a 32 % enhancement in water resistance, a 10 % reduction in water vapor/ammonia permeability, and a 16 % improvement in mechanical properties. These enhanced performances by addition of LDHs were attributed to the combined effects of the tortuous diffusion pathways, and the formation of robust hydrogen bonding networks between the hydroxyl groups of LDHs and PVA/PVP at the organic-inorganic interface. These interactions could reduce free hydroxyl groups on the film surface, leading to hydrophobicity and structural integrity. The composite films exhibited significantly reduced nitrogen permeability under various pH conditions, indicating the improved stability in both acidic and alkaline soil environments. Degradation experiments revealed that the composite film lost 40 % of its mass over 120 days, with a half-life only 8.0 % longer than pure PVA/PVP. These results indicated that the incorporation of LDHs had minimal impact on biodegradability, maintaining the environmental compatibility of the films. These findings highlight the potential of PVA/PVP-LDHs composite films as sustainable, eco-friendly, and efficient slow-release fertilizer coatings, offering a practical solution for improving nitrogen use efficiency and reducing agricultural nitrogen pollution.

Atmospheric ammonia (NH3) has multiple impacts on the environment, climate change, and human health. China is the largest emitter of NH3 globally, with the dynamic inventory of NH3 emissions remaining uncertain. Here, we use the second national agricultural pollution source censuses, integrated satellite data, 15N isotope source apportionment, and multiple models to better understand those key features of NH3 emissions and its environmental impacts in China. Our results show that the total NH3 emissions were estimated to be 11.2 +/- 1.1 million tonnes in 2020, with three emission peaks in April, June, and October, primarily driven by agricultural sources, which contributed 74% of the total emissions. Furthermore, employing a series of quantitative analyses, we estimated the contribution of NH3 emissions to ecosystem impacts. The NH3 emissions have contributed approximately 22% to secondary PM2.5 formation and a 16.6% increase in nitrogen loading of surface waters, while ammonium deposition led to a decrease in soil pH by 0.0032 units and an increase in the terrestrial carbon sink by 44.6 million tonnes in 2020. Reducing agricultural NH3 emissions in China would contribute to the mitigation of air and water pollution challenges, saving damage costs estimated at around 22 billion US dollars due to avoided human and ecosystem health impacts.

The oxidation of ammonia to nitrite, which constitutes the initial and rate-limiting step in the nitrification process, plays a pivotal role in the transformation of ammonia within soil ecosystems. Due to its susceptibility to a range of pollutants, such as heavy metals, pesticides, and pharmaceuticals, nitrification serves as a valuable indicator in the risk assessment of chemical contaminants in soil environments. Here, we analyzed the effects of cadmium (Cd) treatment on soil potential nitrification rate (PNR), and the abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) communities. The results showed that, under 1 day incubation, the soil PNR with Cd 0.5 mg kg(-1) was a little higher but not statistically significant than that with zero mg kg(-1). Then, the soil PNR increased with the increasing Cd concentration from 0.5 to one mg kg(-1), and continuously declined from 1 to 10 mg kg(-1). Moreover, we predicted the bacterial functions of samples with hormetic Cd dose (one mg kg(-1)) by PICURSt (Phylogenetic Investigation of Communities Reconstruction of Unobserved States), and found that the expression of protein disulfide isomerase (PDI) increased with the hormetic Cd dose. PDI is known to enhance the activity of compounds containing -SH or -S-S which can help prevent oxidative damage to membranes. The soil PNR was significantly correlated with AOA abundance rather than AOB, even the abundance of AOB was higher than that of AOA, indicating that AOA functionally predominated over AOB. Our study effectively evaluated the Cd toxicity on soil microbial community and clearly illustrated the ecological niches of AOA and AOB in the agricultural soil system studied, which will be instructive for the sustainable development of agriculture.

Plants activate physiological responses against salinity stress through hormone signaling pathways such as melatonin (M) and methyl jasmonate (MeJ). These hormones trigger defense responses, but comparing their individual and combined effects under salt stress has not been studied. This research investigates defense responses in tomato plants induced by 100 mu M of M and MeJ, along with their combined application (MeJ+M, 100+100 mu M) under non-stress, threshold (0.9 g NaCl kg-1 soil) and severe (1.8 g NaCl kg-1 soil) salinity conditions. Compared to melatonin, MeJ application caused adverse effects, including chlorophyll degradation (34.2 %), root inhibition (17.2 %), and elevated H2O2 (28.9 %), O2-center dot (33.7 %), and malondialdehyde (14.3 %) in the plant under non-stress conditions. Evaluation of the MeJ+M treatment in non-stress conditions indicated that M prevented MeJ-induced damage. Besides, the optimal potassium uptake and plant growth were obtained in the MeJ+M treatment under non-stress and threshold salinity levels. Phytohormones application increased enzymatic antioxidant activity (superoxide dismutase, catalase, ascorbate peroxidase, and peroxidase), modified the activity of phenylalanine ammonia-lyase and polyphenol oxidase, and consequently boosted non-enzymatic antioxidants (phenolic, flavonoid, and anthocyanin content), resulting in a significant reduction of damage from severe salinity stress. However, due to their almost similar physiological changes induced by MeJ, M, and MeJ+M, these treatments were not superior compared to each other in severe stress. Thus, owing to the disruption of the normal morpho-physiological processes in non-stress conditions by MeJ, M can be considered a safer treatment for practical usage. Additionally, the MeJ+M application can not only optimize antioxidant protection under stress conditions but also stimulate plant growth under non-stress conditions.

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.

Mining has led to dramatic ecosystem degradation, the destruction of vegetation and irreversible damage to soil structure and nutrient cycling; additionally, heavy metal (HM) contamination has affected soil nitrogen (N) cycle-associated microorganisms and disrupted soil aggregate structure. To explore the mechanism of soil N recovery in mining areas, we investigated the effects of two N fertilizers (urea (U) and ammonium chloride (AC)) and nine different fertilization patterns on the nitrification process and ammonia oxidizers in soil aggregates via incubation experiments. The results showed that different N treatments had different influences on the distribution of AOA and AOB amoA gene abundance and microbial community structure in soil aggregates. The AOB amoA gene abundance was significantly greater than the AOA amoA gene abundance in aggregates. The dominant species of AOA and AOB were Nitrososphaera and Nitrosospira , respectively, which were mainly found in microaggregates and accounted for 10.3 % to 25.0 % and 31.5 % to 60.1 %, respectively, of the microaggregates. Dissolved organic nitrogen (DON) can be used as an important variable to explain variations in AOA communities, and microbial nitrogen (MBN) content, tartaric acid content, cellulase activity and AOB amoA gene abundance can be used as important variables to explain variations in AOB communities. N fertilizer addition resulted in potential ammonia oxidation (PAO) values ranging from 0.079 to 0.236, 0.100 to 0.5953 and 0.146 to 0.905 mu g.NO2--N d(-1) g(-1) in mega-, macro- and microaggregates, respectively, which suggested that PAO values increased with decreasing aggregate size. In addition, the total nitrification potential (TNP) in macroaggregates was greater than that in mega- and microaggregates, which was the main reason for the increase in the NO3 content in macroaggregates. AOB amoA gene abundance was significantly positively correlated with TNP, and AOB amoA gene abundance was more significantly positively correlated with PAO values than was AOA gene abundance, which suggests that AOB dominated ammonia oxidation and nitrification processes in aggregates. Our research contributes to an understanding of the mechanisms underlying the effects of different types of N fertilizers on nitrification processes and ammonia oxidizers in soil aggregates and provides insights into N management in contaminated soils in mining areas.

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.

Reducing the size of clinoptilolite accentuates its structural attributes, notably mesoporosity and the silicaaluminum ratio, which enhanced its capabilities as an efficient adsorbent and modifier. This research aims to utilize the augmented small -size effect of clinoptilolite to develop a high-performance nano-clinoptilolite based nitrogen (N) fertilizer, to substitute an equivalent amount of urea. To this end, a two-year field experiment was conducted using a single -factor randomized complete block design, involving five different nanoclinoptilolite based N fertilizer mixed with urea (ZN) ratios: control treatment (100% Urea, CK); 20% Z & 80% Urea (Z2N8); 30% Z & 70% Urea (Z3N7); 40% Z & 60% Urea (Z4N6); 50% Z & 50% Urea (Z5N5). This study explored the effects of ZN on ammonia volatilization (AV), N runoff loss, N accumulation, N balance, yield, and ecological benefits in paddy fields. The results showed that Z2N8, Z3N7, Z4N6, and Z5N5 reduced the total AV losses by 8.57%, 20.52%, 30.20%, and 37.13% (two-year average), and reduced runoff losses by 23.29%, 29.93%, 39.66%, and 43.76%, respectively. Additionally, Z2N8, Z3N7, Z4N6, and Z5N5 increased whole -plant N accumulation by 24.32%, 16.84%, 9.00%, 4.85%, and raised rice yield by 15.28%, 10.28%, 6.99%, 5.05%, respectively. This result indicates that ZN can enhance N utilization, although the effectiveness diminishes with an increased application ratio. Furthermore, Z2N8, Z3N7, and Z4N6 lowered N surpluses by 48.77%, 25.84%, and 3.17%, respectively, while Z5N5 resulted in an increase in N surplus by 9.61% relative to the control. Compared to CK, nano-clinoptilolite based N fertilizer replacing 20% of urea (Z2N8) increased income by 14.75%, reduced environmental damage cost by 8.77%, and ultimately boosted net economic benefits by 5.33% and net economic and ecological benefits by 5.75%. In conclusion, Z2N8 can be contemplated as a compound fertilizer to be applied to farmland to enhance both economic and ecological benefits.

Background This study aimed to investigate the alterations in biochemical and physiological responses of oat plants exposed to antimony (Sb) contamination in soil. Specifically, we evaluated the effectiveness of an arbuscular mycorrhizal fungus (AMF) and olive mill waste (OMW) in mitigating the effects of Sb contamination. The soil was treated with a commercial strain of AMF (Rhizophagus irregularis) and OMW (4% w/w) under two different levels of Sb (0 and 1500 mg kg-1 soil).Results The combined treatment (OMW + AMF) enhanced the photosynthetic rate (+ 40%) and chlorophyll a (+ 91%) and chlorophyll b (+ 50%) content under Sb condition, which in turn induced more biomass production (+ 67-78%) compared to the contaminated control plants. More photosynthesis in OMW + AMF-treated plants gives a route for phenylalanine amino acid synthesis (+ 69%), which is used as a precursor for the biosynthesis of secondary metabolites, including flavonoids (+ 110%), polyphenols (+ 26%), and anthocyanins (+ 63%) compared to control plants. More activation of phenylalanine ammonia-lyase (+ 38%) and chalcone synthase (+ 26%) enzymes in OMW + AMF-treated plants under Sb stress indicated the activation of phenylpropanoid pathways in antioxidant metabolites biosynthesis. There was also improved shifting of antioxidant enzyme activities in the ASC/GSH and catalytic pathways in plants in response to OMW + AMF and Sb contamination, remarkably reducing oxidative damage markers.Conclusions While individual applications of OMW and AMF also demonstrated some degree of plant tolerance induction, the combined presence of AMF with OMW supplementation significantly enhanced plant biomass production and adaptability to oxidative stress induced by soil Sb contamination.

Fertilizer-intensive agriculture leads to emissions of reactive nitrogen (Nr), posing threats to climate via nitrous oxide (N2O) and to air quality and human health via nitric oxide (NO) and ammonia (NH3) that form ozone and particulate matter (PM) downwind. Adding nitrification inhibitors (NIs) to fertilizers can mitigate N2O and NO emissions but may stimulate NH3 emissions. Quantifying the net effects of these trade-offs requires spatially resolving changes in emissions and associated impacts. We introduce an assessment framework to quantify such trade-off effects. It deploys an agroecosystem model with enhanced capabilities to predict emissions of Nr with or without the use of NIs, and a social cost of greenhouse gas to monetize the impacts of N2O on climate. The framework also incorporates reduced-complexity air quality and health models to monetize associated impacts of NO and NH3 emissions on human health downwind via ozone and PM. Evaluation of our model against available field measurements showed that it captured the direction of emission changes but underestimated reductions in N2O and overestimated increases in NH3 emissions. The model estimated that, averaged over applicable U.S. agricultural soils, NIs could reduce N2O and NO emissions by an average of 11% and 16%, respectively, while stimulating NH3 emissions by 87%. Impacts are largest in regions with moderate soil temperatures and occur mostly within two to three months of N fertilizer and NI application. An alternative estimate of NI-induced emission changes was obtained by multiplying the baseline emissions from the agroecosystem model by the reported relative changes in Nr emissions suggested from a global meta-analysis: -44% for N2O, -24% for NO and +20% for NH3. Monetized assessments indicate that on an annual scale, NI-induced harms from increased NH3 emissions outweigh (8.5-33.8 times) the benefits of reducing NO and N2O emissions in all agricultural regions, according to model-based estimates. Even under meta-analysis-based estimates, NI-induced damages exceed benefits by a factor of 1.1-4. Our study highlights the importance of considering multiple pollutants when assessing NIs, and underscores the need to mitigate NH3 emissions. Further field studies are needed to evaluate the robustness of multi-pollutant assessments.