The increase in soil temperature associated with climate change has introduced considerable challenges to crop production.Split nitrogen application(SN)represents a potential strategy for improving crop nitrogen use e...The increase in soil temperature associated with climate change has introduced considerable challenges to crop production.Split nitrogen application(SN)represents a potential strategy for improving crop nitrogen use efficiency and enhancing crop stress resistance.Nevertheless,the precise interaction between soil warming(SW)and SN remains unclear.In order to ascertain the impact of SW on maize growth and whether SN can improve the tolerance of maize to SW,a two-year field experiment was conducted(2022-2023).The aim was to examine the influence of two SW ranges(MT,warming 1.40℃;HT,warming 2.75℃)and two nitrogen application methods(N1,one-time basal application of nitrogen fertilizer;N2,one third of base nitrogen fertilizer+two thirds of jointing stage supplemental nitrogen fertilizer)on maize root growth,photosynthetic characteristics,nitrogen use efficiency,and yield.The results demonstrated that SW impeded root growth and precipitated the premature aging of maize leaves following anthesis,particularly in the HT,which led to a notable reduction in maize yield.In comparison to N1,SN has been shown to increase root length density by 8.54%,root bleeding rate by 8.57%,and enhance root distribution ratio in the middle soil layers(20-60 cm).The interaction between SW and SN had a notable impact on maize growth and yield.The SN improved the absorption and utilization efficiency of nitrogen by promoting root development and downward canopy growth,thus improving the tolerance of maize to SW at the later stage of growth.In particular,the N2HT resulted in a 14.51%increase in the photosynthetic rate,a 18.58%increase in nitrogen absorption efficiency,and a 18.32%increase in maize yield compared with N1HT.It can be posited that the SN represents a viable nitrogen management measure with the potential to enhance maize tolerance to soil high-temperature stress.展开更多
Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N...Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N response makes it difficult to predict and quantify the effect of water deficit on crop N status.The nitrogen nutrition index(NNI)has been widely used to accurately diagnose crop N status and to evaluate the effectiveness of N application.The decline of NNI under water-limiting conditions has been documented,although the underlying mechanism governing this decline is not fully understood.This study aimed to elucidate the reason for the decline of NNI under waterlimiting conditions and to provide insights into the accurate utilization of NNI for assessing crop N status under different water-N interaction treatments.Rainout shelter experiments were conducted over three growing seasons from 2018 to 2021 under different N(75 and 225 kg N ha^(-1),low N and high N)and water(120 to 510 mm,W0 to W3)co-limitation treatments.Plant N accumulation,shoot biomass(SB),plant N concentration(%N),soil nitrate-N content,actual evapotranspiration(ET_a),and yield were recorded at the stem elongation,booting,anthesis and grain filling stages.Compared to W0,W1 to W3 treatments exhibited NNI values that were greater by 10.2 to 20.5%,12.6to 24.8%,14 to 24.8%,and 16.8 to 24.8%at stem elongation,booting,anthesis,and grain filling,respectively,across the 2018-2021 seasons.This decline in NNI under water-limiting conditions stemmed from two main factors.First,reduced ET_(a) and SB led to a greater critical N concentration(%N_(c))under water-limiting conditions,which contributed to the decline in NNI primarily under high N conditions.Second,changes in plant%N played a more significant role under low N conditions.Plant N accumulation exhibited a positive allometric relationship with SB and a negative relationship with soil nitrate-N content under water-limiting conditions,indicating co-regulation by SB and the soil nitrate-N content.However,this regulation was influenced by water availability.Plant N accumulation sourced from the soil nitrate-N content reflects soil N availability.Greater soil water availability facilitated greater absorption of soil nitrate-N into the plants,leading to a positive correlation between plant N accumulation and ET_(a)across the different water-N interaction treatments.Therefore,considering the impact of soil water availability is crucial when assessing soil N availability under water-limiting conditions.The findings of this study provide valuable insights into the factors contributing to the decline in NNI among different water-N interaction treatments and can contribute to the more accurate utilization of NNI for assessing winter wheat N status.展开更多
The trade-off between yield and environmental effects caused by nitrogen fertilizer application is an important issue in wheat production.A reduction in fertile florets is one of the main reasons for the lower yields ...The trade-off between yield and environmental effects caused by nitrogen fertilizer application is an important issue in wheat production.A reduction in fertile florets is one of the main reasons for the lower yields under low nitrogen application rates.Brassinosteroids(BRs)have been found to play a role in nitrogen-induced rice spikelet degeneration.However,whether BRs play a role in wheat floret development and the mechanisms involved are not clear.Therefore,a nitrogen gradient experiment and exogenous spraying experiment were conducted to investigate the role and mechanism of BRs in wheat floret development under low nitrogen stress.The results showed that as the nitrogen application decreased,the endogenous BRs content of the spikes decreased,photosynthesis weakened,and total carbon,soluble sugar and starch in the spikes decreased,leading to a reduction in the number of fertile florets.Under low nitrogen stress,exogenous spraying of 24-epibrassinolide promoted photosynthesis,and stimulated stem fructan hydrolysis and the utilization and storage of sucrose in spikes,which directed more carbohydrates to the spikes and increased the number of fertile florets.In conclusion,BRs mediate the effects of nitrogen fertilizer on wheat floret development,and under low nitrogen stress,foliar spraying of 24-epibrassinolide promotes the flow of carbohydrates from the stem to the spikes,alleviating wheat floret degeneration.展开更多
The thermochemical non-equilibrium phenomena encountered by hypersonic vehicles present significant challenges in their design.To investigate the thermochemical reaction flow behind shock waves,the non-equilibrium rad...The thermochemical non-equilibrium phenomena encountered by hypersonic vehicles present significant challenges in their design.To investigate the thermochemical reaction flow behind shock waves,the non-equilibrium radiation in the visible range using a shock tube was studied.Experiments were conducted with a shock velocity of 4.7 km/s,using nitrogen at a pressure of 20 Pa.To address measurement difficulties associated with weak radiation,a special square section shock tube with a side length of 380 mm was utilized.A high-speed camera characterized the shock wave’s morphology,and a spectrograph and a monochromator captured the radiation.The spectra were analyzed,and the numerical spectra were compared with experimental results,showing a close match.Temperature changes behind the shock wave were obtained and compared with numerical predictions.The findings indicate that the vibrational temperatures are overestimated,while the vibrational relaxation time is likely underestimated,due to the oversimplified portrayals of the non-equilibrium relaxation process in the models.Additionally,both experimental and simulated time-resolved profiles of radiation intensity at specific wavelengths were analyzed.The gathered data aims to enhance computational fluid dynamics codes and radiation models,improving their predictive accuracy.展开更多
Ammonia and nitric acid,versatile industrial feedstocks,and burgeoning clean energy vectors hold immense promise for sustainable development.However,Haber–Bosch and Ostwald processes,which generates carbon dioxide as...Ammonia and nitric acid,versatile industrial feedstocks,and burgeoning clean energy vectors hold immense promise for sustainable development.However,Haber–Bosch and Ostwald processes,which generates carbon dioxide as massive by-product,contribute to greenhouse effects and pose environmental challenges.Thus,the pursuit of nitrogen fixation through carbon–neutral pathways under benign conditions is a frontier of scientific topics,with the harnessing of solar energy emerging as an enticing and viable option.This review delves into the refinement strategies for scale-up mild photocatalytic nitrogen fixation,fields ripe with potential for innovation.The narrative is centered on enhancing the intrinsic capabilities of catalysts to surmount current efficiency barriers.Key focus areas include the in-depth exploration of fundamental mechanisms underpinning photocatalytic procedures,rational element selection,and functional planning,state-of-the-art experimental protocols for understanding photo-fixation processes,valid photocatalytic activity evaluation,and the rational design of catalysts.Furthermore,the review offers a suite of forward-looking recommendations aimed at propelling the advancement of mild nitrogen photo-fixation.It scrutinizes the existing challenges and prospects within this burgeoning domain,aspiring to equip researchers with insightful perspectives that can catalyze the evolution of cutting-edge nitrogen fixation methodologies and steer the development of next-generation photocatalytic systems.展开更多
In contrast to research on active sites in nanomaterials,lithium tantalate single crystals,known for their exceptional optical properties and long-range ordered lattice structure,present a promising avenue for in-dept...In contrast to research on active sites in nanomaterials,lithium tantalate single crystals,known for their exceptional optical properties and long-range ordered lattice structure,present a promising avenue for in-depth exploration of photocatalytic reaction systems with fewer constraints imposed by surface chemistry.Typically,the isotropy of a specific facet provides a perfect support for studying heteroatom doping.Herein,this work delves into the intrinsic catalytic sites for photocatalytic nitrogen fixation in iron-doped lithium tantalate single crystals.The presence of iron not only modifies the electronic structure of lithium tantalate,improving its light absorption capacity,but also functions as an active site for the nitrogen adsorption and activation.The photocatalytic ammonia production rate of the iron-doped lithium tantalate in pure water is maximum 26.95μg cm^(−2)h^(−1),which is three times higher than that of undoped lithium tantalate.The combination of first-principles simulations with in situ characterizations confirms that iron doping promotes the rate-determining step and changes the pathway of hydrogenation to associative alternating.This study provides a new perspective on in-depth investigation of intrinsic catalytic active sites in photocatalysis and other catalytic processes.展开更多
To more accurately describe the coal damage and fracture evolution law during liquid nitrogen(LN_(2))fracturing under true triaxial stress,a thermal-hydraulic-mechanical-damage(THMD)coupling model for LN_(2) fracturin...To more accurately describe the coal damage and fracture evolution law during liquid nitrogen(LN_(2))fracturing under true triaxial stress,a thermal-hydraulic-mechanical-damage(THMD)coupling model for LN_(2) fracturing coal was developed,considering the coal heterogeneity and thermophysical parameters of nitrogen.The accuracy and applicability of model were verified by comparing with LN_(2) injection pre-cooling and fracturing experimental data.The effects of different pre-cooling times and horizontal stress ratios on coal damage evolution,permeability,temperature distribution,and fracture characteristics were analyzed.The results show that the permeability and damage of the coal increase exponentially,while the temperature decreases exponentially during the fracturing process.As the pre-cooling time increases,the damage range of the coal expands,and the fracture propagation becomes more pronounced.The initiation pressure and rupture pressure decrease and tend to stabilize with longer precooling times.As the horizontal stress ratio increases,fractures preferentially extend along the direction of maximum horizontal principal stress,leading to a significant decrease in both initiation and rupture pressures.At a horizontal stress ratio of 3,the initiation pressure drops by 48.07%,and the rupture pressure decreases by 41.36%.The results provide a theoretical basis for optimizing LN_(2) fracturing techniques and improving coal seam modification.展开更多
The light-driven CO_(2)reduction reaction(CO_(2)RR)to CO is a very effective way to address global warming.To avoid competition with water photolysis,metal-free gas-solid CO_(2)RR catalysts should be investigated.Cova...The light-driven CO_(2)reduction reaction(CO_(2)RR)to CO is a very effective way to address global warming.To avoid competition with water photolysis,metal-free gas-solid CO_(2)RR catalysts should be investigated.Covalent organic frameworks(COFs)offer a promising approach for CO_(2)transformation but lack high efficiency and selectivity in the absence of metals.Here,we have incorporated a pyridine nitrogen component into the imine-COF conjugated structure(Tp Pym).This innovative system has set a record of producing a CO yield of 1565μmol g^(-1)within 6 h.The soft X-ray absorption fine structure measurement proves that Tp Pym has both better conjugation and electron cloud enrichment.The electronic structure distribution delays the charge-carrier recombination,as evidenced by femtosecond transient absorption spectroscopy.The energy band diagram and theoretical calculation show that the conduction-band potential of Tp Pym is lower and the reduction reaction of CO_(2)to CO is more likely to occur.展开更多
The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate ...The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate change on the structure,function,and services of the ecosystem.However,the spatial distribution and controlling factors of SOC and TN across various soil layers and vegetation types within this unique ecosystem remain inadequately understood.In this study,256 soil samples in 89 sites were collected from the Three River Headwaters Region(TRHR)in China to investigate SOC and TN and to explore the primary factors affecting their distribution,including soil,vegetation,climate,and geography factors.The results show that SOC and TN contents in 0-20,20-40,40-60,and 60-80 cm soil layers are 24.40,18.03,14.04,12.40 g/kg and 2.46,1.90,1.51,1.17 g/kg,respectively;with higher concentrations observed in the southeastern region compared to the northwest of the TRHR.One-way analysis of variance reveals that SOC and TN levels are elevated in the alpine meadow and the alpine shrub relative to the alpine steppe in the 0-60 cm soil layers.The structural equation model explores that soil water content is the main controlling factor affecting the variation of SOC and TN.Moreover,the geography,climate,and vegetation factors notably indirectly affect SOC and TN through soil factors.Therefore,it can effectively improve soil water and nutrient conditions through vegetation restoration,soil improvement,and grazing management,and the change of SOC and TN can be fully understood by establishing monitoring networks to better protect soil carbon and nitrogen.展开更多
The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation ...The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation and oxygen evolution competition,sluggish kinetics,low Faradaic efficiency,and limited nitrate yields.In this work,a novel two-dimensional(2D)layered MOF Mn-BCPPy(H_(2)BCPPy=3,5-di(4'-carboxyphenyl)pyridine)has been successfully synthesized.The framework is composed of a rod-manganese motifs and possesses abundant active sites including open metal sites(OMSs)and Lewis base sites(LBSs).The Mn-BCPPy is the first MOF catalyst applied in electrocatalytic NOR which NO_(3)^(-)exhibited relatively high activity with a yield of 99.75μg/(h·mg)and a Faraday efficiency(FE)of 32.09%.Furthermore,it can be used as fluorescent sensor for selectively and sensitively detect nitrofuran antibiotics(NFs).Therefore,this work explores the application of MOF materials in the field of electrocatalytic NOR,which reveals that manganese-based MOFs have great potential prospects.展开更多
Nitrogen doping in chemical vapor deposition-derived ultrananocrystalline diamond(UNCD)films in-creases the electronic conductivity,yet its microstructural effects on electron transport are insufficiently understood.W...Nitrogen doping in chemical vapor deposition-derived ultrananocrystalline diamond(UNCD)films in-creases the electronic conductivity,yet its microstructural effects on electron transport are insufficiently understood.We investigated the formation of nitrogen-induced diaph-ite structures(hybrid diamond-graphite phases)and their role in changing the conductivity.Nitrogen doping in a hy-drogen-rich plasma environment promotes the emergence of unique sp^(3)-sp^(2)bonding interfaces,where diamond grains are covalently integrated with graphitic domains,facilitating a structure-driven electronic transition.High-resolution transmis-sion electron microscopy and selected area electron diffraction reveal five-fold,six-fold and twelve-fold symmetries,along with an atypical{200}crystallographic reflection,confirming diaphite formation in 5%and 10%N-doped UNCD films,while high-er doping levels(15%and 20%)result in extensive graphitization.Raman spectroscopy tracks the evolution of sp^(2)bonding with increasing nitrogen content,while atomic force microscopy and X-ray diffraction indicate a consistent diamond grain size of~8 nm.Cryogenic electronic transport measurements reveal a conductivity increase from 8.72 to 708 S/cm as the nitrogen dop-ing level increases from 5%to 20%,which is attributed to defect-mediated carrier transport and 3D weak localization.The res-ulting conductivity is three orders of magnitude higher than previously reported.These findings establish a direct correlation between diaphite structural polymorphism and tunable electronic properties in nitrogen-doped UNCD films,offering new ways for defect-engineering diamond-based electronic materials.展开更多
In dryland ecosystems,nitrogen(N)is the primary limiting factor after water availability,constraining both plant productivity and organic matter decomposition while also regulating ecosystem function and service provi...In dryland ecosystems,nitrogen(N)is the primary limiting factor after water availability,constraining both plant productivity and organic matter decomposition while also regulating ecosystem function and service provision.However,the distributions of different soil N fraction stocks in drylands and the factors that influence them remain poorly understood.In this study,we collected 2076 soil samples from 173 sites across the drylands of northern China during the summers of 2021 and 2022.Using the best-performing eXtreme Gradient Boosting(XGBoost)model,we mapped the spatial distributions of the soil N fraction stocks and identified the key drivers of their variability.Our findings revealed that the stocks of total nitrogen(TN),inorganic nitrogen(IN),and microbial biomass nitrogen(MBN)in the top 30 cm soil layer were 1020.4,92.2,and 40.8 Tg,respectively,with corresponding mean densities of 164.6,14.9,and 6.6 g/m2.Climate variables-particularly mean annual temperature and aridity-along with human impacts emerged as the dominant drivers of soil N stock distribution.Notably,increased aridity and intensified human impacts exerted mutually counteracting effects on soil N fractions:aridity-driven moisture limitation generally suppressed N accumulation,whereas anthropogenic activities(e.g.,fertilization and grazing)promoted N enrichment.By identifying the key environmental and anthropogenic factors shaping the soil N distribution,this study improves the accuracy of regional and global N stock estimates.These insights provide a scientific foundation for developing more effective soil N management strategies in dryland ecosystems,contributing to sustainable land use and long-term ecosystem resilience in drylands.展开更多
Soil nitrogen(N)is the main limiting nutrient for plant growth,which is sensitive to variations in the soil oxygen environment.To provide insights into plant N accumulation and yield under aerated and drip irrigation,...Soil nitrogen(N)is the main limiting nutrient for plant growth,which is sensitive to variations in the soil oxygen environment.To provide insights into plant N accumulation and yield under aerated and drip irrigation,a greenhouse tomato experiment was conducted with six treatments,including three fertilization types:inorganic fertilizer(NPK);organic fertilizer(OM);chemical(75%of applied N)+organic fertilizer(25%)(NPK+OM)under drip irrigation(DI)and aerated irrigation(AI)methods.Under Al,total soil carbon mineralization(C_(min))was significantly higher(by 5.7-7.0%)than under DI irrigation.C_(min)in the fertilizer treatments followed the order NPK+OM>OM>NPK under both AI and DI.Potentially mineralizable C(C_(0))and N(N_(0))was greater under AI than under DI.Gross N mineralization,gross nitrification,and NH_(4)^(+)immobilization rates were significantly higher under the AINPK treatment than the DINPK treatment by 2.58-3.27-,1.25-1.44-,and 1-1.26-fold,respectively.These findings demonstrated that AI and the addition of organic fertilizer accelerated the turnover of soil organic matter and N transformation processes,thereby enhancing N availability.Moreover,the combination of AI and organic fertilizer application was found to promote root growth(8.4-10.6%),increase the duration of the period of rapid N accumulation(ΔT),and increase the maximum N accumulation rate(V_(max)),subsequently encouraging aboveground dry matter accumulation.Consequently,the AI treatment yield was significantly greater(by 6.3-12.4%)than under the DI treatment.Further,N partial factor productivity(NPFP)and N harvest index(NHI)were greater under AI than under DI,by 6.3 to 12.4%,and 4.6 to 8.1%,respectively.The rankings of yield and NPFP remained consistent,with NPK+OM>OM>NPK under both AI and DI treatments.These results highlighted the positive impacts of AI and organic fertilizer application on soil N availability,N uptake,and overall crop yield in tomato.The optimal management measure was identified as the AINPK+OM treatment,which led to more efficient N management,better crop growth,higher yield,and more sustainable agricultural practices.展开更多
Light and nitrogen(N)are two critically environmental factors essential for plant survival,as they constitute the fundamental molecular framework of plant cells and significantly influence patterns of plant growth and...Light and nitrogen(N)are two critically environmental factors essential for plant survival,as they constitute the fundamental molecular framework of plant cells and significantly influence patterns of plant growth and development.Light is the driving force behind photosynthesis,a process that converts light energy into chemical energy stored as sugars.Additionally,light acts as a direct signal that can modulate plant morphogenesis and structural development.Nitrogen,as the most crucial mineral nutrient for plants,is a component of numerous biomolecules.It also functions as a signaling molecule,regulating plant growth and development.Moreover,light and nitrogen directly regulate the balance of carbon(C)and N within plants,affecting numerous biochemical reactions and various physiological processes.This review focuses on the interactions between light and nitrogen in physiological,metabolic,and molecular levels.We will also discuss the regulatory networks and mechanisms through which light and nitrogen influence C and N absorption and metabolism in plants.展开更多
The responses of drip-irrigated rice physiological traits to water and fertilizers have been widely studied.However,the responses of yield,root traits and their plasticity to the nitrogen environment in different nitr...The responses of drip-irrigated rice physiological traits to water and fertilizers have been widely studied.However,the responses of yield,root traits and their plasticity to the nitrogen environment in different nitrogen-efficient cultivars are not fully understood.An experiment was conducted from 2020-2022 with a high nitrogen use efficiency(high-NUE)cultivar(T-43)and a low-NUE cultivar(LX-3),and four nitrogen levels(0,150,300,and 450 kg ha^(-1))under drip irrigation in large fields.The aim was to study the relationships between root morphology,conformation,biomass,and endogenous hormone contents,yield and NUE.The results showed three main points:1)Under the same N application rate,compared with LX-3,the yield,N partial factor productivity(PFP),fine root length density(FRLD),shoot dry weight(SDW),root indole-3-acetic acid(IAA),and root zeatin and zeatin riboside(Z+ZR)of T-43 were significantly greater by11.4-18.9,11.3-13.5,11.6-15.7,9.9-31.1,6.1-48.1,and 22.8-73.6%,respectively,while the root-shoot ratio(RSR)and root abscisic acid(ABA)were significantly lower(P<0.05);2)nitrogen treatment significantly increased the rice root morphological indexes and endogenous hormone contents(P<0.05).Compared to N0,the yield,RLD,surface area density(SAD),root volume density(RVD),and root endogenous hormones(IAA,Z+ZR)were significantly increased in both cultivars under N2 by 61.6-71.6,64.2-74.0,69.9-105.6,6.67-9.91,54.0-67.8,and 51.4-58.9%,respectively.Compared with N3,the PFP and N agronomic efficiency(NAE)of nitrogen fertilizer under N2 increased by 52.3-62.4 and39.2-63.0%,respectively;3)the responses of root trait plasticity to the N environment significantly differed between the cultivars(P<0.05).Compared with LX-3,T-43 showed a longer root length and larger specific surface area,which is a strategy for adapting to changes in the nutrient environment.For the rice cultivar with high-NUE,the RSR was optimized by increasing the FRLD,root distribution in upper soil layers,and root endogenous hormones(IAA,Z+ZR)under suitable nitrogen conditions(N2).An efficient nutrient acquisition strategy can occur through root plasticity,leading to greater yield and NUE.展开更多
Synchronizing the nitrogen(N)supply of slow-and controlled-release N fertilizers(SCRNFs)with rice N demand is essential in replacing multiple urea applications with a single basal application of SCRNFs.Traditional ass...Synchronizing the nitrogen(N)supply of slow-and controlled-release N fertilizers(SCRNFs)with rice N demand is essential in replacing multiple urea applications with a single basal application of SCRNFs.Traditional assessment of N supply characteristics primarily examines N release patterns,which are limited to coated SCRNFs and disregard N transformation mechanisms,necessitating a more universal and reliable index.Based on the capacity of crop N status to detect N deficiency or excess,we hypothesized that utilizing leaf N balance index(NBI)as a measure of N status could offer novel insights into assessing N supply characteristics of SCRNFs.Field experiments were conducted with four individual SCRNFs-humic acid urea(HAU),sulfur-coated urea(SCU),urease inhibitor urea(UIU),and polymer-coated urea(PCU)and their four combined forms,alongside high-yield urea split application as control(CK).The results revealed that NBI dynamics relative to CK reflected the N supply potential of different SCRNFs while categorizing them as short-,medium-,and long-acting fertilizers.Combinations incorporating the long-acting SCRNF(PCU)consistently demonstrated superior performance in yield(by 5.5%)and N use efficiency(by 42.8%)through providing more consistent and efficient N supply throughout the rice growth cycle.Grain yield exhibited negative correlation with the difference in NBI dynamics between SCRNFs and CK,suggesting that synchronizing N supply between one-time application of SCRNFs and conventional high-yield fertilization is crucial for high yield.These findings demonstrate the potential of N status diagnosed by leaf NBI to evaluate N supply characteristics of SCRNFs and highlight the importance of synchronized N supply for a one-time SCRNF application.展开更多
Climate change impacts soil nitrogen, influencing plant responses to elevated atmospheric [CO2]. Understanding the interaction between nitrogen supply and elevated [CO2] is crucial for predicting plant future performa...Climate change impacts soil nitrogen, influencing plant responses to elevated atmospheric [CO2]. Understanding the interaction between nitrogen supply and elevated [CO2] is crucial for predicting plant future performance. This study examined the interactive effects of elevated [CO2] and nitrogen supply on the eco-physiological performance of yellow birch. Seedlings were exposed to two [CO2] levels and five nitrogen supply levels for 4 months. Growth parameters such as seedling height and root collar diameter increased with higher nitrogen supply and elevated [CO2], while specific leaf area decreased. [CO2] elevation and increasing nitrogen supply also increased the total and stem, and leaf biomass. The elevated [CO2] increased the stem mass ratio but decreased the root-to-shoot ratio and root mass ratio. However, decreases in nitrogen supply increased root mass ratio and root-to-shoot ratio. The elevated [CO2] increased the maximum rate of Rubisco carboxylation (Vcmax) and photosynthetic electron transport (Jmax), but the effect on Jmax was statistically significant only at the two highest nitrogen supply levels. The results indicate that yellow birch may increase photosynthetic capacity, biomass, and growth in the future when [CO2] is higher.展开更多
Long-term excessive nitrogen(N)application neither increases nor enhances grain yield and N use efficiency(NUE)of maize,yet the mechanisms involving root morphological and physiological characteristics remain unclear....Long-term excessive nitrogen(N)application neither increases nor enhances grain yield and N use efficiency(NUE)of maize,yet the mechanisms involving root morphological and physiological characteristics remain unclear.This study aimed to elucidate the mechanisms underlying stagnant grain yield under excessive N application by examining root morphological and physiological characteristics.A 10-year N fertilizer trial was conducted in Jilin Province,Northeast China,cultivating maize at three N fertilizer levels(zero N,N0;recommended N,N2;and high N level,N4)from 2019 to 2021.Two widely cultivated maize genotypes,‘Xianyu 335’(XY335)and‘Zhengdan 958’(ZD958),were evaluated.Grain yield,N content,root morphology,and physiological characteristics were analyzed to assess the relationships between N uptake,N utilization,plant growth,and root systems under different N treatments.Compared to N0,root biomass,post-silking N uptake,and grain yield improved significantly with increased N input,while no significant differences emerged between recommended N and high N.High N application enhanced root length and root surface area but decreased root activity(measured by TTC(2,3,5-triphenyltetrazolium chloride)method),nitrate reductase activity,and root activity absorbing area across genotypes.Root length and root to shoot ratio negatively affected N uptake(by-1.2 and-24.6%),while root surface area,root activity,nitrate reductase activity,and root activity absorbing area contributed positively.The interaction between cultivar and N application significantly influenced NUE.XY335 achieved the highest NUE(11.6%)and N recovery efficiency(18.4%)through superior root surface area(23.6%),root activity(12.5%),nitrate reductase activity(8.3%),and root activity absorbing area(6.9%)compared to other treatments.Recommended N application enhanced Post N uptake,NUE,and grain yield through improved root characteristics,while high N application failed to increase or decreased NUE by reducing these parameters.This study demonstrates that root surface area,root activity,nitrate reductase activity,and root activity absorbing area limit NUE increase under high N application.展开更多
Symbiotic nitrogen fixation in members of the Fabaceae family is highly efficient and beneficial for global agriculture,but not all species in this family form root nodules with rhizobial bacteria.Nodulation mainly oc...Symbiotic nitrogen fixation in members of the Fabaceae family is highly efficient and beneficial for global agriculture,but not all species in this family form root nodules with rhizobial bacteria.Nodulation mainly occurs in plants belonging to the Papilionoideae and Caesalpinioideae subfamilies(Tederso0 et al.,2018;van Velzen et al.,2019).Nodulation mechanisms in Fabaceae are well studied(Yang et al.,2022),and genomic comparisons of nodulating and non-nodulating host species can provide valuable insights into the evolutionary and genetic basis of this key process.展开更多
Nitrogen(N)is the most important nutrient for plants;however,microbe-mediated N transformation under different N forms is unclear.This experiment investigated the effects of four treatments fertilized with various N f...Nitrogen(N)is the most important nutrient for plants;however,microbe-mediated N transformation under different N forms is unclear.This experiment investigated the effects of four treatments fertilized with various N forms,no N(control,CK),100%ammonium N(AN),100%nitrate N(NN),and 50%ammonium N+50%nitrate N(ANNN),on soil chemical properties,rhizosphere bacterial network,and rice growth.The ANNN treatment enhanced soil pH by 6.9%,soil organic carbon by 12%,and microbial biomass N(MBN)by 60%compared to CK.The linear discriminant effect size(LEfSe)analysis indicated four highly abundant biomarkers of bacterial communities each in the CK,NN,and AN treatments,while the ANNN treatment showed six highly abundant biomarkers with maximum effect size and linear discriminant analysis(LDA)score>4.The 16S rRNA gene-predicted functions under PICRUST indicated glutathione metabolism and proteasome and Tax4Fun recorded amino acid metabolism in the ANNN treatment.The combination of ammonium and nitrate N(i.e.,the ANNN treatment)significantly increased the expression levels of the genes encoding N metabolism,including AMT1,NRT2.1,GS1,and GOGAT1,and induced 39%,27%,35%,and 38%increase in nitrate reductase,nitrite reductase,glutamine synthetase,and glutamate synthase,respectively,in comparison to CK.In addition,the ANNN treatment promoted rice leaf photosynthetic rate by 37%,transpiration rate by 41%,CO_(2) exchange rate by 11%,and stomatal conductance by 18%compared to CK,while increased N use efficiency(NUE)by 10%and 19%,respectively,compared to the AN and NN treatments.These findings suggest that the combination of ammonium and nitrate N can promote bacterial community abundance,composition,and functional pathways by improving soil properties and can increase NUE and rice growth.This study provides a theoretical basis for the rational application of N fertilizers and the implications of this approach for future sustainable crop production.展开更多
基金supported by the Natural Science Fund of China(31771724)the Key Research and Development Project of Shaanxi Province(2024NC-ZDCYL-01-10).
文摘The increase in soil temperature associated with climate change has introduced considerable challenges to crop production.Split nitrogen application(SN)represents a potential strategy for improving crop nitrogen use efficiency and enhancing crop stress resistance.Nevertheless,the precise interaction between soil warming(SW)and SN remains unclear.In order to ascertain the impact of SW on maize growth and whether SN can improve the tolerance of maize to SW,a two-year field experiment was conducted(2022-2023).The aim was to examine the influence of two SW ranges(MT,warming 1.40℃;HT,warming 2.75℃)and two nitrogen application methods(N1,one-time basal application of nitrogen fertilizer;N2,one third of base nitrogen fertilizer+two thirds of jointing stage supplemental nitrogen fertilizer)on maize root growth,photosynthetic characteristics,nitrogen use efficiency,and yield.The results demonstrated that SW impeded root growth and precipitated the premature aging of maize leaves following anthesis,particularly in the HT,which led to a notable reduction in maize yield.In comparison to N1,SN has been shown to increase root length density by 8.54%,root bleeding rate by 8.57%,and enhance root distribution ratio in the middle soil layers(20-60 cm).The interaction between SW and SN had a notable impact on maize growth and yield.The SN improved the absorption and utilization efficiency of nitrogen by promoting root development and downward canopy growth,thus improving the tolerance of maize to SW at the later stage of growth.In particular,the N2HT resulted in a 14.51%increase in the photosynthetic rate,a 18.58%increase in nitrogen absorption efficiency,and a 18.32%increase in maize yield compared with N1HT.It can be posited that the SN represents a viable nitrogen management measure with the potential to enhance maize tolerance to soil high-temperature stress.
基金supported by the National Natural Science Foundation of China(51609247)the Henan Provincial Natural Science Foundation,China(222300420589,202300410553)+4 种基金the Central Public-interest Scientific Institution Basal Research Fund,China(FIRI2022-22)the Science&Technology Fundamental Resources Investigation Program,China(2022FY101601)the Science and Technology Project of Xinxiang City,Henan Province,China(GG2021024)the Major Special Science and Technology Project of Henan Province,China(221100110700)the Joint Fund of Science and Technology Research and Development Plan of Henan Province,China(Superior Discipline Cultivation)(222301420104)。
文摘Nitrogen(N)uptake is regulated by water availability,and a water deficit can limit crop N responses by reducing N uptake and utilization.The complex and multifaceted interplay between water availability and the crop N response makes it difficult to predict and quantify the effect of water deficit on crop N status.The nitrogen nutrition index(NNI)has been widely used to accurately diagnose crop N status and to evaluate the effectiveness of N application.The decline of NNI under water-limiting conditions has been documented,although the underlying mechanism governing this decline is not fully understood.This study aimed to elucidate the reason for the decline of NNI under waterlimiting conditions and to provide insights into the accurate utilization of NNI for assessing crop N status under different water-N interaction treatments.Rainout shelter experiments were conducted over three growing seasons from 2018 to 2021 under different N(75 and 225 kg N ha^(-1),low N and high N)and water(120 to 510 mm,W0 to W3)co-limitation treatments.Plant N accumulation,shoot biomass(SB),plant N concentration(%N),soil nitrate-N content,actual evapotranspiration(ET_a),and yield were recorded at the stem elongation,booting,anthesis and grain filling stages.Compared to W0,W1 to W3 treatments exhibited NNI values that were greater by 10.2 to 20.5%,12.6to 24.8%,14 to 24.8%,and 16.8 to 24.8%at stem elongation,booting,anthesis,and grain filling,respectively,across the 2018-2021 seasons.This decline in NNI under water-limiting conditions stemmed from two main factors.First,reduced ET_(a) and SB led to a greater critical N concentration(%N_(c))under water-limiting conditions,which contributed to the decline in NNI primarily under high N conditions.Second,changes in plant%N played a more significant role under low N conditions.Plant N accumulation exhibited a positive allometric relationship with SB and a negative relationship with soil nitrate-N content under water-limiting conditions,indicating co-regulation by SB and the soil nitrate-N content.However,this regulation was influenced by water availability.Plant N accumulation sourced from the soil nitrate-N content reflects soil N availability.Greater soil water availability facilitated greater absorption of soil nitrate-N into the plants,leading to a positive correlation between plant N accumulation and ET_(a)across the different water-N interaction treatments.Therefore,considering the impact of soil water availability is crucial when assessing soil N availability under water-limiting conditions.The findings of this study provide valuable insights into the factors contributing to the decline in NNI among different water-N interaction treatments and can contribute to the more accurate utilization of NNI for assessing winter wheat N status.
基金supported by the Key Research and Development Program of Shaanxi,China(2021NY-083)the National Natural Science Foundation of China(31871567)。
文摘The trade-off between yield and environmental effects caused by nitrogen fertilizer application is an important issue in wheat production.A reduction in fertile florets is one of the main reasons for the lower yields under low nitrogen application rates.Brassinosteroids(BRs)have been found to play a role in nitrogen-induced rice spikelet degeneration.However,whether BRs play a role in wheat floret development and the mechanisms involved are not clear.Therefore,a nitrogen gradient experiment and exogenous spraying experiment were conducted to investigate the role and mechanism of BRs in wheat floret development under low nitrogen stress.The results showed that as the nitrogen application decreased,the endogenous BRs content of the spikes decreased,photosynthesis weakened,and total carbon,soluble sugar and starch in the spikes decreased,leading to a reduction in the number of fertile florets.Under low nitrogen stress,exogenous spraying of 24-epibrassinolide promoted photosynthesis,and stimulated stem fructan hydrolysis and the utilization and storage of sucrose in spikes,which directed more carbohydrates to the spikes and increased the number of fertile florets.In conclusion,BRs mediate the effects of nitrogen fertilizer on wheat floret development,and under low nitrogen stress,foliar spraying of 24-epibrassinolide promotes the flow of carbohydrates from the stem to the spikes,alleviating wheat floret degeneration.
基金supported by the Key-Area Research and Development Program of Guangdong Province(Grant No.2021B0909060004)the National Natural Science Foundation of China(Grant Nos.12072355 and 92271117)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0620202).
文摘The thermochemical non-equilibrium phenomena encountered by hypersonic vehicles present significant challenges in their design.To investigate the thermochemical reaction flow behind shock waves,the non-equilibrium radiation in the visible range using a shock tube was studied.Experiments were conducted with a shock velocity of 4.7 km/s,using nitrogen at a pressure of 20 Pa.To address measurement difficulties associated with weak radiation,a special square section shock tube with a side length of 380 mm was utilized.A high-speed camera characterized the shock wave’s morphology,and a spectrograph and a monochromator captured the radiation.The spectra were analyzed,and the numerical spectra were compared with experimental results,showing a close match.Temperature changes behind the shock wave were obtained and compared with numerical predictions.The findings indicate that the vibrational temperatures are overestimated,while the vibrational relaxation time is likely underestimated,due to the oversimplified portrayals of the non-equilibrium relaxation process in the models.Additionally,both experimental and simulated time-resolved profiles of radiation intensity at specific wavelengths were analyzed.The gathered data aims to enhance computational fluid dynamics codes and radiation models,improving their predictive accuracy.
基金financially supported by the National Natural Science Foundation of China(No.21675131)the Volkswagen Foundation(Freigeist Fellowship No.89592)+1 种基金the Natural Science Foundation of Chongqing(No.2020jcyj-zdxmX0003,CSTB2023NSCQ-MSX0924)the National Research Foundation,Singapore,and A*STAR(Agency for Science Technology and Research)under its LCER Phase 2 Programme Hydrogen&Emerging Technologies FI,Directed Hydrogen Programme(Award No.U2305D4003).
文摘Ammonia and nitric acid,versatile industrial feedstocks,and burgeoning clean energy vectors hold immense promise for sustainable development.However,Haber–Bosch and Ostwald processes,which generates carbon dioxide as massive by-product,contribute to greenhouse effects and pose environmental challenges.Thus,the pursuit of nitrogen fixation through carbon–neutral pathways under benign conditions is a frontier of scientific topics,with the harnessing of solar energy emerging as an enticing and viable option.This review delves into the refinement strategies for scale-up mild photocatalytic nitrogen fixation,fields ripe with potential for innovation.The narrative is centered on enhancing the intrinsic capabilities of catalysts to surmount current efficiency barriers.Key focus areas include the in-depth exploration of fundamental mechanisms underpinning photocatalytic procedures,rational element selection,and functional planning,state-of-the-art experimental protocols for understanding photo-fixation processes,valid photocatalytic activity evaluation,and the rational design of catalysts.Furthermore,the review offers a suite of forward-looking recommendations aimed at propelling the advancement of mild nitrogen photo-fixation.It scrutinizes the existing challenges and prospects within this burgeoning domain,aspiring to equip researchers with insightful perspectives that can catalyze the evolution of cutting-edge nitrogen fixation methodologies and steer the development of next-generation photocatalytic systems.
基金supported by Natural Science Foundation of Shandong Province(Nos.ZR2022YQ42,ZR2021JQ15,ZR2021QE011,ZR2021ZD20,2022GJJLJRC-01)Innovative Team Project of Jinan(No.2021GXRC019)the National Natural Science Foundation of China(Nos.52022037,52202366).
文摘In contrast to research on active sites in nanomaterials,lithium tantalate single crystals,known for their exceptional optical properties and long-range ordered lattice structure,present a promising avenue for in-depth exploration of photocatalytic reaction systems with fewer constraints imposed by surface chemistry.Typically,the isotropy of a specific facet provides a perfect support for studying heteroatom doping.Herein,this work delves into the intrinsic catalytic sites for photocatalytic nitrogen fixation in iron-doped lithium tantalate single crystals.The presence of iron not only modifies the electronic structure of lithium tantalate,improving its light absorption capacity,but also functions as an active site for the nitrogen adsorption and activation.The photocatalytic ammonia production rate of the iron-doped lithium tantalate in pure water is maximum 26.95μg cm^(−2)h^(−1),which is three times higher than that of undoped lithium tantalate.The combination of first-principles simulations with in situ characterizations confirms that iron doping promotes the rate-determining step and changes the pathway of hydrogenation to associative alternating.This study provides a new perspective on in-depth investigation of intrinsic catalytic active sites in photocatalysis and other catalytic processes.
基金financially supported by the National Natural Science Foundation of China(Nos.51874236 and 52174207)Shaanxi Science and Technology Innovation Team(No.2022TD02)Henan University of Science and Technology PhD Funded Projects(No.B2025-9)。
文摘To more accurately describe the coal damage and fracture evolution law during liquid nitrogen(LN_(2))fracturing under true triaxial stress,a thermal-hydraulic-mechanical-damage(THMD)coupling model for LN_(2) fracturing coal was developed,considering the coal heterogeneity and thermophysical parameters of nitrogen.The accuracy and applicability of model were verified by comparing with LN_(2) injection pre-cooling and fracturing experimental data.The effects of different pre-cooling times and horizontal stress ratios on coal damage evolution,permeability,temperature distribution,and fracture characteristics were analyzed.The results show that the permeability and damage of the coal increase exponentially,while the temperature decreases exponentially during the fracturing process.As the pre-cooling time increases,the damage range of the coal expands,and the fracture propagation becomes more pronounced.The initiation pressure and rupture pressure decrease and tend to stabilize with longer precooling times.As the horizontal stress ratio increases,fractures preferentially extend along the direction of maximum horizontal principal stress,leading to a significant decrease in both initiation and rupture pressures.At a horizontal stress ratio of 3,the initiation pressure drops by 48.07%,and the rupture pressure decreases by 41.36%.The results provide a theoretical basis for optimizing LN_(2) fracturing techniques and improving coal seam modification.
基金supported by the National Natural Science Foundation of China(Nos.22375031,22202037,22472023)the Fundamental Research Funds for the Central Universities(Nos.2412023YQ001,2412023QD019,2412024QD014)+1 种基金supported by grants from the seventh batch of Jilin Province Youth Science and Technology Talent Lifting Project(No.QT202305)Science and Technology Development Plan Project of Jilin Province,China(No.20240101192JC)。
文摘The light-driven CO_(2)reduction reaction(CO_(2)RR)to CO is a very effective way to address global warming.To avoid competition with water photolysis,metal-free gas-solid CO_(2)RR catalysts should be investigated.Covalent organic frameworks(COFs)offer a promising approach for CO_(2)transformation but lack high efficiency and selectivity in the absence of metals.Here,we have incorporated a pyridine nitrogen component into the imine-COF conjugated structure(Tp Pym).This innovative system has set a record of producing a CO yield of 1565μmol g^(-1)within 6 h.The soft X-ray absorption fine structure measurement proves that Tp Pym has both better conjugation and electron cloud enrichment.The electronic structure distribution delays the charge-carrier recombination,as evidenced by femtosecond transient absorption spectroscopy.The energy band diagram and theoretical calculation show that the conduction-band potential of Tp Pym is lower and the reduction reaction of CO_(2)to CO is more likely to occur.
基金supported by the National Science Foundation for Distinguished Young Scholars(No.42425107)Ecological Civilization Special Project of Key Research&and Development Program in Gansu Province(No.24YFFA009)the Top Talent Project of Gansu Province,Chinese Academy of Sciences Young Crossover Team Project(No.JCTD-2022-18)。
文摘The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate change on the structure,function,and services of the ecosystem.However,the spatial distribution and controlling factors of SOC and TN across various soil layers and vegetation types within this unique ecosystem remain inadequately understood.In this study,256 soil samples in 89 sites were collected from the Three River Headwaters Region(TRHR)in China to investigate SOC and TN and to explore the primary factors affecting their distribution,including soil,vegetation,climate,and geography factors.The results show that SOC and TN contents in 0-20,20-40,40-60,and 60-80 cm soil layers are 24.40,18.03,14.04,12.40 g/kg and 2.46,1.90,1.51,1.17 g/kg,respectively;with higher concentrations observed in the southeastern region compared to the northwest of the TRHR.One-way analysis of variance reveals that SOC and TN levels are elevated in the alpine meadow and the alpine shrub relative to the alpine steppe in the 0-60 cm soil layers.The structural equation model explores that soil water content is the main controlling factor affecting the variation of SOC and TN.Moreover,the geography,climate,and vegetation factors notably indirectly affect SOC and TN through soil factors.Therefore,it can effectively improve soil water and nutrient conditions through vegetation restoration,soil improvement,and grazing management,and the change of SOC and TN can be fully understood by establishing monitoring networks to better protect soil carbon and nitrogen.
基金supported by Natural Science Foundation of Shandong Province(ZR2021MB075)Fundamental Research Funds for the Central Universities,Ocean University of China(202461021).
文摘The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation and oxygen evolution competition,sluggish kinetics,low Faradaic efficiency,and limited nitrate yields.In this work,a novel two-dimensional(2D)layered MOF Mn-BCPPy(H_(2)BCPPy=3,5-di(4'-carboxyphenyl)pyridine)has been successfully synthesized.The framework is composed of a rod-manganese motifs and possesses abundant active sites including open metal sites(OMSs)and Lewis base sites(LBSs).The Mn-BCPPy is the first MOF catalyst applied in electrocatalytic NOR which NO_(3)^(-)exhibited relatively high activity with a yield of 99.75μg/(h·mg)and a Faraday efficiency(FE)of 32.09%.Furthermore,it can be used as fluorescent sensor for selectively and sensitively detect nitrofuran antibiotics(NFs).Therefore,this work explores the application of MOF materials in the field of electrocatalytic NOR,which reveals that manganese-based MOFs have great potential prospects.
文摘Nitrogen doping in chemical vapor deposition-derived ultrananocrystalline diamond(UNCD)films in-creases the electronic conductivity,yet its microstructural effects on electron transport are insufficiently understood.We investigated the formation of nitrogen-induced diaph-ite structures(hybrid diamond-graphite phases)and their role in changing the conductivity.Nitrogen doping in a hy-drogen-rich plasma environment promotes the emergence of unique sp^(3)-sp^(2)bonding interfaces,where diamond grains are covalently integrated with graphitic domains,facilitating a structure-driven electronic transition.High-resolution transmis-sion electron microscopy and selected area electron diffraction reveal five-fold,six-fold and twelve-fold symmetries,along with an atypical{200}crystallographic reflection,confirming diaphite formation in 5%and 10%N-doped UNCD films,while high-er doping levels(15%and 20%)result in extensive graphitization.Raman spectroscopy tracks the evolution of sp^(2)bonding with increasing nitrogen content,while atomic force microscopy and X-ray diffraction indicate a consistent diamond grain size of~8 nm.Cryogenic electronic transport measurements reveal a conductivity increase from 8.72 to 708 S/cm as the nitrogen dop-ing level increases from 5%to 20%,which is attributed to defect-mediated carrier transport and 3D weak localization.The res-ulting conductivity is three orders of magnitude higher than previously reported.These findings establish a direct correlation between diaphite structural polymorphism and tunable electronic properties in nitrogen-doped UNCD films,offering new ways for defect-engineering diamond-based electronic materials.
基金supported by the Xinjiang Outstanding Youth Fund(2021D01E03)the Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01D083)the National Natural Science Foundation of China(U2003214,41977099).
文摘In dryland ecosystems,nitrogen(N)is the primary limiting factor after water availability,constraining both plant productivity and organic matter decomposition while also regulating ecosystem function and service provision.However,the distributions of different soil N fraction stocks in drylands and the factors that influence them remain poorly understood.In this study,we collected 2076 soil samples from 173 sites across the drylands of northern China during the summers of 2021 and 2022.Using the best-performing eXtreme Gradient Boosting(XGBoost)model,we mapped the spatial distributions of the soil N fraction stocks and identified the key drivers of their variability.Our findings revealed that the stocks of total nitrogen(TN),inorganic nitrogen(IN),and microbial biomass nitrogen(MBN)in the top 30 cm soil layer were 1020.4,92.2,and 40.8 Tg,respectively,with corresponding mean densities of 164.6,14.9,and 6.6 g/m2.Climate variables-particularly mean annual temperature and aridity-along with human impacts emerged as the dominant drivers of soil N stock distribution.Notably,increased aridity and intensified human impacts exerted mutually counteracting effects on soil N fractions:aridity-driven moisture limitation generally suppressed N accumulation,whereas anthropogenic activities(e.g.,fertilization and grazing)promoted N enrichment.By identifying the key environmental and anthropogenic factors shaping the soil N distribution,this study improves the accuracy of regional and global N stock estimates.These insights provide a scientific foundation for developing more effective soil N management strategies in dryland ecosystems,contributing to sustainable land use and long-term ecosystem resilience in drylands.
基金supported by the National Natural Science Foundation of China for Young Scholars(52109066)the Postdoctoral Science Foundation of Shaanxi Province,China(2023BSHTBZZ29)the China Postdoctoral Science Foundation(2022M712604 and 2023T160534).
文摘Soil nitrogen(N)is the main limiting nutrient for plant growth,which is sensitive to variations in the soil oxygen environment.To provide insights into plant N accumulation and yield under aerated and drip irrigation,a greenhouse tomato experiment was conducted with six treatments,including three fertilization types:inorganic fertilizer(NPK);organic fertilizer(OM);chemical(75%of applied N)+organic fertilizer(25%)(NPK+OM)under drip irrigation(DI)and aerated irrigation(AI)methods.Under Al,total soil carbon mineralization(C_(min))was significantly higher(by 5.7-7.0%)than under DI irrigation.C_(min)in the fertilizer treatments followed the order NPK+OM>OM>NPK under both AI and DI.Potentially mineralizable C(C_(0))and N(N_(0))was greater under AI than under DI.Gross N mineralization,gross nitrification,and NH_(4)^(+)immobilization rates were significantly higher under the AINPK treatment than the DINPK treatment by 2.58-3.27-,1.25-1.44-,and 1-1.26-fold,respectively.These findings demonstrated that AI and the addition of organic fertilizer accelerated the turnover of soil organic matter and N transformation processes,thereby enhancing N availability.Moreover,the combination of AI and organic fertilizer application was found to promote root growth(8.4-10.6%),increase the duration of the period of rapid N accumulation(ΔT),and increase the maximum N accumulation rate(V_(max)),subsequently encouraging aboveground dry matter accumulation.Consequently,the AI treatment yield was significantly greater(by 6.3-12.4%)than under the DI treatment.Further,N partial factor productivity(NPFP)and N harvest index(NHI)were greater under AI than under DI,by 6.3 to 12.4%,and 4.6 to 8.1%,respectively.The rankings of yield and NPFP remained consistent,with NPK+OM>OM>NPK under both AI and DI treatments.These results highlighted the positive impacts of AI and organic fertilizer application on soil N availability,N uptake,and overall crop yield in tomato.The optimal management measure was identified as the AINPK+OM treatment,which led to more efficient N management,better crop growth,higher yield,and more sustainable agricultural practices.
基金supported by grants from Hainan Seed Laboratory(B21HJ0003)the National Natural Science Foundation of China(U23A20185)the Hainan Excellent Talent Team。
文摘Light and nitrogen(N)are two critically environmental factors essential for plant survival,as they constitute the fundamental molecular framework of plant cells and significantly influence patterns of plant growth and development.Light is the driving force behind photosynthesis,a process that converts light energy into chemical energy stored as sugars.Additionally,light acts as a direct signal that can modulate plant morphogenesis and structural development.Nitrogen,as the most crucial mineral nutrient for plants,is a component of numerous biomolecules.It also functions as a signaling molecule,regulating plant growth and development.Moreover,light and nitrogen directly regulate the balance of carbon(C)and N within plants,affecting numerous biochemical reactions and various physiological processes.This review focuses on the interactions between light and nitrogen in physiological,metabolic,and molecular levels.We will also discuss the regulatory networks and mechanisms through which light and nitrogen influence C and N absorption and metabolism in plants.
基金supported by the National Natural Science Foundation of China(31860345 and 31460541)the Youth Innovative Top Talents Project of Shihezi University,China(CXBJ202003)the Third Division of Xinjiang Production and Construction Corps Scientific and Technological Achievements Transfer and Transformation Project,China(KJ2023CG03)。
文摘The responses of drip-irrigated rice physiological traits to water and fertilizers have been widely studied.However,the responses of yield,root traits and their plasticity to the nitrogen environment in different nitrogen-efficient cultivars are not fully understood.An experiment was conducted from 2020-2022 with a high nitrogen use efficiency(high-NUE)cultivar(T-43)and a low-NUE cultivar(LX-3),and four nitrogen levels(0,150,300,and 450 kg ha^(-1))under drip irrigation in large fields.The aim was to study the relationships between root morphology,conformation,biomass,and endogenous hormone contents,yield and NUE.The results showed three main points:1)Under the same N application rate,compared with LX-3,the yield,N partial factor productivity(PFP),fine root length density(FRLD),shoot dry weight(SDW),root indole-3-acetic acid(IAA),and root zeatin and zeatin riboside(Z+ZR)of T-43 were significantly greater by11.4-18.9,11.3-13.5,11.6-15.7,9.9-31.1,6.1-48.1,and 22.8-73.6%,respectively,while the root-shoot ratio(RSR)and root abscisic acid(ABA)were significantly lower(P<0.05);2)nitrogen treatment significantly increased the rice root morphological indexes and endogenous hormone contents(P<0.05).Compared to N0,the yield,RLD,surface area density(SAD),root volume density(RVD),and root endogenous hormones(IAA,Z+ZR)were significantly increased in both cultivars under N2 by 61.6-71.6,64.2-74.0,69.9-105.6,6.67-9.91,54.0-67.8,and 51.4-58.9%,respectively.Compared with N3,the PFP and N agronomic efficiency(NAE)of nitrogen fertilizer under N2 increased by 52.3-62.4 and39.2-63.0%,respectively;3)the responses of root trait plasticity to the N environment significantly differed between the cultivars(P<0.05).Compared with LX-3,T-43 showed a longer root length and larger specific surface area,which is a strategy for adapting to changes in the nutrient environment.For the rice cultivar with high-NUE,the RSR was optimized by increasing the FRLD,root distribution in upper soil layers,and root endogenous hormones(IAA,Z+ZR)under suitable nitrogen conditions(N2).An efficient nutrient acquisition strategy can occur through root plasticity,leading to greater yield and NUE.
基金the Natural Science Foundation of Jiangsu Province,China(BK20200539)the Jiangsu Provincial Key Research and Development Program,China(BE2019377 and BE2019343)the Science and Technology Planning Program of Suzhou,China(ST202228).
文摘Synchronizing the nitrogen(N)supply of slow-and controlled-release N fertilizers(SCRNFs)with rice N demand is essential in replacing multiple urea applications with a single basal application of SCRNFs.Traditional assessment of N supply characteristics primarily examines N release patterns,which are limited to coated SCRNFs and disregard N transformation mechanisms,necessitating a more universal and reliable index.Based on the capacity of crop N status to detect N deficiency or excess,we hypothesized that utilizing leaf N balance index(NBI)as a measure of N status could offer novel insights into assessing N supply characteristics of SCRNFs.Field experiments were conducted with four individual SCRNFs-humic acid urea(HAU),sulfur-coated urea(SCU),urease inhibitor urea(UIU),and polymer-coated urea(PCU)and their four combined forms,alongside high-yield urea split application as control(CK).The results revealed that NBI dynamics relative to CK reflected the N supply potential of different SCRNFs while categorizing them as short-,medium-,and long-acting fertilizers.Combinations incorporating the long-acting SCRNF(PCU)consistently demonstrated superior performance in yield(by 5.5%)and N use efficiency(by 42.8%)through providing more consistent and efficient N supply throughout the rice growth cycle.Grain yield exhibited negative correlation with the difference in NBI dynamics between SCRNFs and CK,suggesting that synchronizing N supply between one-time application of SCRNFs and conventional high-yield fertilization is crucial for high yield.These findings demonstrate the potential of N status diagnosed by leaf NBI to evaluate N supply characteristics of SCRNFs and highlight the importance of synchronized N supply for a one-time SCRNF application.
文摘Climate change impacts soil nitrogen, influencing plant responses to elevated atmospheric [CO2]. Understanding the interaction between nitrogen supply and elevated [CO2] is crucial for predicting plant future performance. This study examined the interactive effects of elevated [CO2] and nitrogen supply on the eco-physiological performance of yellow birch. Seedlings were exposed to two [CO2] levels and five nitrogen supply levels for 4 months. Growth parameters such as seedling height and root collar diameter increased with higher nitrogen supply and elevated [CO2], while specific leaf area decreased. [CO2] elevation and increasing nitrogen supply also increased the total and stem, and leaf biomass. The elevated [CO2] increased the stem mass ratio but decreased the root-to-shoot ratio and root mass ratio. However, decreases in nitrogen supply increased root mass ratio and root-to-shoot ratio. The elevated [CO2] increased the maximum rate of Rubisco carboxylation (Vcmax) and photosynthetic electron transport (Jmax), but the effect on Jmax was statistically significant only at the two highest nitrogen supply levels. The results indicate that yellow birch may increase photosynthetic capacity, biomass, and growth in the future when [CO2] is higher.
基金supported by the National Key Research and Development Program of China(2023YFD2301702)the earmarked Fund for China Agriculture Research System(CARS-02)the National Natural Science Foundation of China(31971852).
文摘Long-term excessive nitrogen(N)application neither increases nor enhances grain yield and N use efficiency(NUE)of maize,yet the mechanisms involving root morphological and physiological characteristics remain unclear.This study aimed to elucidate the mechanisms underlying stagnant grain yield under excessive N application by examining root morphological and physiological characteristics.A 10-year N fertilizer trial was conducted in Jilin Province,Northeast China,cultivating maize at three N fertilizer levels(zero N,N0;recommended N,N2;and high N level,N4)from 2019 to 2021.Two widely cultivated maize genotypes,‘Xianyu 335’(XY335)and‘Zhengdan 958’(ZD958),were evaluated.Grain yield,N content,root morphology,and physiological characteristics were analyzed to assess the relationships between N uptake,N utilization,plant growth,and root systems under different N treatments.Compared to N0,root biomass,post-silking N uptake,and grain yield improved significantly with increased N input,while no significant differences emerged between recommended N and high N.High N application enhanced root length and root surface area but decreased root activity(measured by TTC(2,3,5-triphenyltetrazolium chloride)method),nitrate reductase activity,and root activity absorbing area across genotypes.Root length and root to shoot ratio negatively affected N uptake(by-1.2 and-24.6%),while root surface area,root activity,nitrate reductase activity,and root activity absorbing area contributed positively.The interaction between cultivar and N application significantly influenced NUE.XY335 achieved the highest NUE(11.6%)and N recovery efficiency(18.4%)through superior root surface area(23.6%),root activity(12.5%),nitrate reductase activity(8.3%),and root activity absorbing area(6.9%)compared to other treatments.Recommended N application enhanced Post N uptake,NUE,and grain yield through improved root characteristics,while high N application failed to increase or decreased NUE by reducing these parameters.This study demonstrates that root surface area,root activity,nitrate reductase activity,and root activity absorbing area limit NUE increase under high N application.
基金supported by the National Natural Science Foundation of China(No.32160142)Guangxi Natural Science Foundation(No.2023GXNSFDA026034)+3 种基金State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources(SKLCUSAb202302)to H.W.,the National Natural Science Foundation of China(No.32460062)to Y.L.,and 1+9 Leading the Charge with Open Competition'project of Sichuan Academy of Agricultural Sciences(1+9KJGG010)Fruit tree breeding project in Sichuan Province(2021YFYZ0023)to H.X.
文摘Symbiotic nitrogen fixation in members of the Fabaceae family is highly efficient and beneficial for global agriculture,but not all species in this family form root nodules with rhizobial bacteria.Nodulation mainly occurs in plants belonging to the Papilionoideae and Caesalpinioideae subfamilies(Tederso0 et al.,2018;van Velzen et al.,2019).Nodulation mechanisms in Fabaceae are well studied(Yang et al.,2022),and genomic comparisons of nodulating and non-nodulating host species can provide valuable insights into the evolutionary and genetic basis of this key process.
基金financially supported by the National Natural Science Foundation of China(No.32172109)the Natural Science Foundation of Guangdong Province,China(No.2021A1515010566).
文摘Nitrogen(N)is the most important nutrient for plants;however,microbe-mediated N transformation under different N forms is unclear.This experiment investigated the effects of four treatments fertilized with various N forms,no N(control,CK),100%ammonium N(AN),100%nitrate N(NN),and 50%ammonium N+50%nitrate N(ANNN),on soil chemical properties,rhizosphere bacterial network,and rice growth.The ANNN treatment enhanced soil pH by 6.9%,soil organic carbon by 12%,and microbial biomass N(MBN)by 60%compared to CK.The linear discriminant effect size(LEfSe)analysis indicated four highly abundant biomarkers of bacterial communities each in the CK,NN,and AN treatments,while the ANNN treatment showed six highly abundant biomarkers with maximum effect size and linear discriminant analysis(LDA)score>4.The 16S rRNA gene-predicted functions under PICRUST indicated glutathione metabolism and proteasome and Tax4Fun recorded amino acid metabolism in the ANNN treatment.The combination of ammonium and nitrate N(i.e.,the ANNN treatment)significantly increased the expression levels of the genes encoding N metabolism,including AMT1,NRT2.1,GS1,and GOGAT1,and induced 39%,27%,35%,and 38%increase in nitrate reductase,nitrite reductase,glutamine synthetase,and glutamate synthase,respectively,in comparison to CK.In addition,the ANNN treatment promoted rice leaf photosynthetic rate by 37%,transpiration rate by 41%,CO_(2) exchange rate by 11%,and stomatal conductance by 18%compared to CK,while increased N use efficiency(NUE)by 10%and 19%,respectively,compared to the AN and NN treatments.These findings suggest that the combination of ammonium and nitrate N can promote bacterial community abundance,composition,and functional pathways by improving soil properties and can increase NUE and rice growth.This study provides a theoretical basis for the rational application of N fertilizers and the implications of this approach for future sustainable crop production.
