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
Nitrogen(N)and phosphorus(P)are mineral nutrients essential for plant growth and development,playing a crucial role throughout the plant life cycle.Cotton,a globally significant textile crop,has a particularly high de...Nitrogen(N)and phosphorus(P)are mineral nutrients essential for plant growth and development,playing a crucial role throughout the plant life cycle.Cotton,a globally significant textile crop,has a particularly high demand for N fertilizer across its developmental stages.This review explores the effects of adequate or deficient N and P levels on cotton growth phases,focusing on their influence on physiological processes and molecular mechanisms.Key topics include the regulation of N-and P-related enzymes,hormones,and genes,as well as the complex interplay of N-and P-related signaling pathways from the aspects of N-P signaling integration to regulate root development,N-P signaling integration to regulate nutrient uptake,and regulation of N-P interactions—a frontier in current research.Strategies for improving N and P use efficiency are also discussed,including developing high-efficiency cotton cultivars and identifying functional genes to enhance productivity.Generally speaking,we take model plants as a reference in the hope of coming up with new strategies for the efficient utilization of N and P in cotton.展开更多
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
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
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
Polymeric nitrogen is a potential high-energy-density material with the advantages of high energy density, easy availability of raw materials, and non-pollution. The design and synthesis of polymeric nitrogen are impo...Polymeric nitrogen is a potential high-energy-density material with the advantages of high energy density, easy availability of raw materials, and non-pollution. The design and synthesis of polymeric nitrogen are important in the research field of energetic materials. The cubic gauche nitrogen was successfully synthesized at high pressure in the diamond anvil cell, which stimulated the theoretical and experimental investigations. To date, several hundred kinds of polymeric nitrogen have been reported. This review introduces the progressive development of polymeric nitrogen with high energy density, the challenges faced by the synthesized polymeric nitrogen under high-pressure,and the importance to improve the stability of polymeric nitrogen at ambient pressure. Furthermore, alternative methods for synthesizing polymeric nitrogen under moderate conditions are also presented. In this field, more efforts are needed to develop strategies for stabilizing more polymeric nitrogen to ambient conditions, especially the stability of free surfaces.展开更多
Recent studies have shown that mucilage secretion from aerial roots is an essential feature of modern maize inbred lines,with some retaining the nitrogen-fixing capabilities of ancient landraces.To explore the genetic...Recent studies have shown that mucilage secretion from aerial roots is an essential feature of modern maize inbred lines,with some retaining the nitrogen-fixing capabilities of ancient landraces.To explore the genetic basis of nitrogen fixation in mucilage and its evolution from teosinte(Zea mays ssp.mexicana)to modern maize,we developed a recombinant inbred line(RIL)population from teosinte and cultivated it under low-nitrogen conditions.Large-scale,multi-year,and multi-environment analyses of RIL-Teo,Doubled Haploid-A(DH-A),Doubled Haploid-B(DH-B),and association populations led to the identification of 15 quantitative trait loci(QTL),68 quantitative trait nucleotides(QTN),and 59 candidate genes linked to mucilage secretion from aerial roots.Functional verification of the candidate gene ZmAco3,which is associated with mucilage secretion in aerial roots,demonstrated that deletion of this gene resulted in a reduction in mucilage secretion in aerial roots.In addition,most maize inbred lines exhibited stronger mucilage secretion from aerial roots under low-nitrogen conditions than under normal-nitrogen conditions.We categorized mucilage secretion into constitutive and low-nitrogen-inducible types.Through genotype-by-environment interaction studies,8 QTL,16 QTN,and 19 candidate genes were identified,revealing the genetic mechanisms underlying mucilage secretion under low-nitrogen conditions.These findings provide a comprehensive genetic analysis of the mucilage-secreting ability of maize aerial roots,contributing to our understanding of nitrogen fixation and offering potential avenues for enhancing nitrogen fixation in modern maize lines.This research advances knowledge of plant nutrient acquisition strategies and has implications for sustainable agricultural practices.展开更多
Various forms of nitrogen(N)discharged by high-intensity human activities in the Yangtze River Delta are transported into the lake along the river channel,accelerating the lake’s N cycle and increasing the eutrophica...Various forms of nitrogen(N)discharged by high-intensity human activities in the Yangtze River Delta are transported into the lake along the river channel,accelerating the lake’s N cycle and increasing the eutrophication ecological risk.Taihu Lake is a typical eutrophic shallowlake,suffering fromcyanobacteria blooms for decades due to excessive exogenous nutrient load.In this study,the coupling relationship between basin N loss and lake responsewas established by combining N flow and exogenous nutrient load.The results showed striking spatiotemporal differences and the large tributaries input themajority of N.Three evolution stages of the lake ecosystem were classified,i.e.,Stage A(1980–1997)with slow increasing N load;Stage B(1998–2006)with high-level N load despite some controlling methods;Stage C(2007 to present)with the strengthening of N management in lake basin after the Water Crisis,the N load has gradually decreased,while the water flow is increasing by the year.Environmental N export in the basin was 581.46 kg/ha N in 2021,and a total of 32.06 Gg N was finally drawn into the lake.Over the recent two decades,the noticeable expansion of built-up land from 8.21%to 21.04%associated with its environmental impacts i.e.,urban heat island effect,hard pavement,and ecological fragility deserves attention.Accordingly,the rapid climate change of the basin became the key factor driving the tributaries’hydrologic conditions(r_(∂)=0.945).The developed social economy dominated the sewage discharge(r_(∂)=0.857).The N inputs and losses to the environment in the basin can be further exacerbated without control.Meanwhile,the lake would respond to the exogenous input.In addition to the self-cleaning part of the lake,the N accumulation rate of the surface sediment ranged from 3.29 to 10.77 g N/(m^(2)·yr)of Taihu Lake.To meet the pollutant control target,around 66.28 Gg anthropogenic N needs to be reduced in the upper stream area yearly.Clarifying the N flow and its environmental burden can mitigate its damage to the ecosystem and take on the refined management on the watershed scale.展开更多
The yield of maize(Zea mays L.)is highly influenced by nitrogen fertilization.This study investigated the impact of nitrogen fertilization on morphophysiological traits in maize(Zea mays L.)and developed algorithms to...The yield of maize(Zea mays L.)is highly influenced by nitrogen fertilization.This study investigated the impact of nitrogen fertilization on morphophysiological traits in maize(Zea mays L.)and developed algorithms to relate manual phenotyping and digital phenotyping of maize with leaf nitrogen and digital field image traits.The experiment included three hybrid maize varieties,V1(Hybrid 981),V2(BARI Hybrid maize-9),and V3(Hybrid P3396),which were evaluated across three nitrogen levels(N1=100 kg N ha^(−1),N2=200 kg N ha^(−1),N3=300 kg N ha^(−1))in a split-plot design with three replications.The results revealed that nitrogen levels(N),varieties(V),and their interactions(V×N)significantly influenced traits such as plant height(PH),leaf area index(LAI),normalized difference vegetation index(NDVI),canopy cover(CC),chlorophyll content(Chl a and Chl b),leaf nitrogen content(LNC),total dry matter(TDM),and grain yield.The hybrid P3396 with 300 kg N ha^(−1)(V3N3)achieved the highest grain yield of 14.45 t ha^(−1),which was statistically similar to that of Hybrid 981 and 300 kg N ha^(−1)(V1N3).Nitrogen significantly improved dry matter accumulation,leaf area,and physiological parameters,with maximum values recorded during flowering.The NDVI,CC,and SPAD were strongly correlated with LNC and TDM,highlighting their potential as indicators for nitrogen management.The digital imaging traits analysed via software effectively differentiated the nitrogen treatments,demonstrating their utility for precise nitrogen application.In conclusion,nitrogen fertilization at 300 kg N ha^(−1) optimized the growth and yield of hybrid maize,with Hybrid P3396 performing best.This study underscores the role of advanced phenotyping tools in improving nitrogen use efficiency and sustainable maize production.展开更多
The unreasonable application of nitrogen fertilizer poses a threat to agricultural productivity and the environment protection in Northeast China.Therefore,accurately assessing crop nitrogen requirements and optimizin...The unreasonable application of nitrogen fertilizer poses a threat to agricultural productivity and the environment protection in Northeast China.Therefore,accurately assessing crop nitrogen requirements and optimizing fertilization are crucial for sustainable agricultural production.A three-year field experiment was conducted to evaluate the effects of planting density on the critical nitrogen concentration dilution curve(CNDC)for spring maize under drip irrigation and fertilization integration,incorporating two planting densities:D1(60,000 plants ha^(-1))and D2(90,000 plants ha^(-1))and six nitrogen levels:no nitrogen(N0),90(N90),180(N180),270(N270),360(N360),and 450(N450)kg ha^(-1).A Bayesian hierarchical model was used to develop CNDC models based on dry matter(DM)and leaf area index(LAI).The results revealed that the critical nitrogen concentration exhibited a power function relationship with both DM and LAI,while planting density had no significant impact on the CNDC parameters.Based on these findings,we propose unified CNDC equations for maize under drip irrigation and fertilization integration:Nc=4.505DM-0.384(based on DM)and Nc=3.793LAI-0.327(based on LAI).Additionally,the nitrogen nutrition index(NNI),derived from the CNDC,increased with higher nitrogen application rates.The nitrogen nutrition index(NNI)approached 1 with a nitrogen application rate of 180 kg ha^(-1)under the D1 planting density,while it reached 1 at 270 kg ha^(-1)under the D2 planting density.The relationship between NNI and relative yield(RY)followed a“linear+plateau”model,with maximum RY observed when the NNI approached 1.Thus,under the condition of drip irrigation and fertilization integration in Northeast China’s spring maize production,the optimal nitrogen application rates for achieving the highest yields were 180 kg ha^(-1)at a planting density of 60,000 plants ha^(-1),and 270 kg ha^(-1)at a density of 90,000 plants ha^(-1).The CNDC and NNI models developed in this study are valuable tools for diagnosing nitrogen nutrition and guiding precise fertilization practices in maize production under integrated drip irrigation and fertilization systems in Northeast China.展开更多
The effcacy of integrating green manure in arid irrigation regions to enhance maize yield and nitrogen(N)uptake effciency has been extensively explored.However,limited research has delineated the contribution of green...The effcacy of integrating green manure in arid irrigation regions to enhance maize yield and nitrogen(N)uptake effciency has been extensively explored.However,limited research has delineated the contribution of green manure N vs.soil N on crop N utilization effciency.This study integrated feld experiments with micro-plot experiments to examine green manure(common vetch)management practices for achieving high maize yield and N uptake.In a micro-plot experiment,^(15)N technology was utilized to label green manure crops.Five treatments were applied in the research methodology:conventional tillage without green manure as the control(CT),tillage with total green manure incorporation(TG),no-tillage with total green manure mulching(NTG),tillage with only root incorporation(T),and no-tillage with removal of aboveground green manure(NT).The results of the micro-plot experiment were consistent with those observed in the feld,demonstrating that the utilization of green manure substantially increased maize yield and nitrogen uptake effciency(NUPE)compared to CT.In particular,under NTG,N uptake by maize from green manure was higher than NT and T,accounting for 59.1%of maize N uptake.Furthermore,applying NTG boosted the NUPE of soil N in maize to 50.7%,higher than TG by 5.5%.Meanwhile,it decreased the proportion of soil N in the maize.The difference between NTG and TG was primarily shown in the maize grains.For N transport in the soil,NTG decreased N loss while increasing soil N retention.Also,it facilitated the mineralization of soil organic N before the fowering stage.In conclusion,adopting no-tillage with total green manure mulching increased N uptake from green manure and the soil and decreased the proportion of soil-derived N in maize.展开更多
A comprehensive insight into the evolution and molecular structure of basic and neutral nitrogen compounds during the residue hydrotreating(RHT)process was gained through ESI(+)/ESI(-)FT-ICR MS analysis of the feedsto...A comprehensive insight into the evolution and molecular structure of basic and neutral nitrogen compounds during the residue hydrotreating(RHT)process was gained through ESI(+)/ESI(-)FT-ICR MS analysis of the feedstock and its hydrogenated samples,with hydrodenitrogenation(HDN)ratios of 15.9%-70.1%.This study revealed that carbazoles,characterized by a double bond equivalent(DBE)of 9-11,were the refractory neutral nitrogen compounds during the RHT process.Their recalcitrant nature was primarily due to their low aromaticity and high steric hindrance.Conversely,quinolines(DBEs 7 to 9)were the most abundant basic nitrogen compounds.Through a meticulous analysis of DBE evolution,we revealed the intricate reaction mechanisms of benzocarbazoles and dibenzocarbazoles in residual oil,highlighting the crucial role of quinolines as key intermediates in eliminating these compounds.Interestingly,nitrogen compounds with either low or high carbon numbers(for a given DBE)exhibited higher reactivity than those with medium carbon numbers,which can be attributed to the low steric hindrance resulting from short alkyl chains and more naphthenic-aromatic structures,respectively.After hydrotreatment,the molecular structures of the most refractory or abundant nitrogen compounds could consist of two main types:those with multiple naphthenic-aromatic rings and those with long side chains near the nitrogen atom.This research has revealed nitrogen compounds'evolutionary mechanisms and refractory nature,and the molecular structure of the most resistant or abundant basic and neutral nitrogen compounds,providing a deeper understanding of the HDN process and ultimately paving the way for the rational RHT catalyst design and process development.展开更多
The four-decade quest for synthesizing ambient-stable polymeric nitrogen,a promising high-energy-density material,remains an unsolved challenge in materials science.We develop a multi-stage computational strategy empl...The four-decade quest for synthesizing ambient-stable polymeric nitrogen,a promising high-energy-density material,remains an unsolved challenge in materials science.We develop a multi-stage computational strategy employing density functional tight-binding-based rapid screening combined with density functional theory refinement and global structure searching,effectively bridging computational efficiency with quantum accuracy.This integrated approach identifies four novel polymeric nitrogen phases(Fddd,P3221,I4m2,and𝑃P6522)that are thermodynamically stable at ambient pressure.Remarkably,the helical𝑃6522 configuration demonstrates exceptional thermal resilience up to 1500 K,representing a predicted polymeric nitrogen structure that maintains stability under both atmospheric pressure and high-temperature extremes.Our methodology establishes a paradigm-shifting framework for the accelerated discovery of metastable energetic materials,resolving critical bottlenecks in theoretical predictions while providing experimentally actionable targets for polymeric nitrogen synthesis.展开更多
Background Nitrogen-Use-Efficiency(NUE)in lactating dairy cows,defined as milk nitrogen(N)output as a proportion of N consumed,is low,with the majority of excess N excreted in manure.Excreted N can be lost to the envi...Background Nitrogen-Use-Efficiency(NUE)in lactating dairy cows,defined as milk nitrogen(N)output as a proportion of N consumed,is low,with the majority of excess N excreted in manure.Excreted N can be lost to the environment as ammonia gas leading to environmental acidification and nutrient enrichment of sensitive habitats,and to watercourses contributing to aquatic eutrophication.While there is much evidence that NUE can be improved by reducing the crude protein(CP)content of dairy cow diets,the long-term impacts of feeding lower protein diets on cow performance and the rumen microbiome are less well understood.This study examined the effects of reducing the CP contents of dairy cow diets on cow performance,NUE,the relationship between NUE and residual feed intake(RFI),and the rumen microbiome.Results Dietary CP content did not affect feed intake,milk yield or milk composition(P>0.05),except for milk urea N(MUN),which increased with increasing diet CP content(P<0.05).The mean NUE was 34%,34%and 31%for the LCP(low-protein,15%),MCP(medium-protein,16%),and HCP(high-protein,17%)diets,respectively.RFI was negatively correlated with NUE(r=−0.57,P<0.001).The rumen ammonia-N concentrations increased with increasing dietary CP;however,the ruminal pH and volatile fatty acid(VFA)content of the rumen fluid remained constant.Predicted urinary N excretion was greater in the HCP and MCP diets than in the LCP diet.Reducing dietary CP content in dairy cow diets did not affect microbial composition,diversity and functional profiles.The family Bacteroidaceae was more abundant in HE(high-efficiency)cows,whereas the Methanobacteriaceae and the genus Methanobrevibacter were more abundant in LE(low-efficiency)cows.Additionally,propanoate metabolism,cysteine and methionine metabolism and amino acid biosynthesis pathways were more abundant in HE cows,whilst the methane(CH4)metabolism pathway was upregulated in LE cows.Conclusions The results demonstrate that diet CP can be reduced with no loss in cow performance,but with an associated reduction in N excretion.The abundance of microbial populations differed between low and high efficiency cows,which may contribute to the differences in efficiency observed.展开更多
Nitrogen and phosphorus (NP) deposition can change the nutrient input of forest ecosystems. The effects of NP deposition on soil aggregate need to be analyzed to propose effective environmental management strategies. ...Nitrogen and phosphorus (NP) deposition can change the nutrient input of forest ecosystems. The effects of NP deposition on soil aggregate need to be analyzed to propose effective environmental management strategies. In this study, representative Korean pine mixed forests and Korean pine plantations in northeastern China were selected. Soil samples were sieved to obtain four different particle sizes of soil aggregates (> 2, 2–0.25, 0.25–0.053, and < 0.053 mm). Four NP treatments were applied to simulate N and P deposition, and an indoor incubation experiment was conducted over a period of 360 d. Total nitrogen, microbial nitrogen, dissolved organic nitrogen, hydrolyzed nitrogen, NH_(4)^(+)–N, NO_(3)^(−)–N content, and extracellular enzyme activities of NAG, LAP, and AP were determined. Different fractions of N responded differently to NP addition. Lower NP addition had a greater promoting effect on aggregate N compared to higher NP addition. NAG was the main extracellular enzyme affecting N in both forest types. NP addition had a greater effect on the extracellular enzyme activities of the soil aggregates from the Korean pine plantations. These results enhance our understanding of the effects of NP addition on soil nitrogen within temperate forest ecosystems.展开更多
Efficient nitrogen management is crucial for developing sustainable strategies aimed at enhancing yield while mitigating negative environmental impacts.However,research focusing on this aspect in the production of fre...Efficient nitrogen management is crucial for developing sustainable strategies aimed at enhancing yield while mitigating negative environmental impacts.However,research focusing on this aspect in the production of fresh maize is limited.Therefore,this study analyzed the effects of nitrogen application rates on the yields of 40 sweet and 44 waxy maize varieties at five sites in Zhejiang Province,China,from 2015 to 2019.The nitrogen application rates were categorized as either relatively high(RHN,>300 kg ha^(-1) for sweet maize and>320 kg ha^(-1) for waxy maize)or relatively low(RLN).An increase in nitrogen application rates significantly reduced nitrogen fertilizer partial productivity in both sweet and waxy maize(R^(2)=0.616,P<0.01;R^(2)=0.643,P<0.01),indicating that the optimum nitrogen application rates in this study might be the lowest values(160 kg ha^(-1) for sweet maize and 180 kg ha^(-1) for waxy maize).The kernel number per ear of sweet maize had a potentially more significant impact on fresh grain yield than the 1,000-fresh kernel weight under both RLN and RHN.In waxy maize,1,000-kernel weight contributed more to fresh grain yield under RLN,while kernel number per ear and 1,000-kernel weight cooperatively affected the yield under RHN.This study found that sweet maize required taller plant and ear heights,along with an optimal ear-plant height ratio,to enhance dry matter accumulation and increase source size,particularly under RLN,and to ultimately achieve a higher fresh grain yield.In contrast,a lower ear height and ear-plant height ratio in waxy maize probably contributed more to the greater kernel number and weight under RLN,likely due to a lower ear height which can reduce the distance between sink and source,enabling more efficient photoassimilate allocation to the ear.展开更多
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 Supported by National Key Laboratory of Cotton Bio-breeding and Integrated Utilization(CB2023C07)Xinjiang Autonomous Region"Three Agricultural"Backbone Talent Training Program(2022SNGGNT024)Xinjiang Huyanghe City Science and Technology Program(2023C08).
文摘Nitrogen(N)and phosphorus(P)are mineral nutrients essential for plant growth and development,playing a crucial role throughout the plant life cycle.Cotton,a globally significant textile crop,has a particularly high demand for N fertilizer across its developmental stages.This review explores the effects of adequate or deficient N and P levels on cotton growth phases,focusing on their influence on physiological processes and molecular mechanisms.Key topics include the regulation of N-and P-related enzymes,hormones,and genes,as well as the complex interplay of N-and P-related signaling pathways from the aspects of N-P signaling integration to regulate root development,N-P signaling integration to regulate nutrient uptake,and regulation of N-P interactions—a frontier in current research.Strategies for improving N and P use efficiency are also discussed,including developing high-efficiency cotton cultivars and identifying functional genes to enhance productivity.Generally speaking,we take model plants as a reference in the hope of coming up with new strategies for the efficient utilization of N and P in cotton.
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 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.
基金supported by the CASHIPS Director’s Fund (Grant No. YZJJ202207-CX)。
文摘Polymeric nitrogen is a potential high-energy-density material with the advantages of high energy density, easy availability of raw materials, and non-pollution. The design and synthesis of polymeric nitrogen are important in the research field of energetic materials. The cubic gauche nitrogen was successfully synthesized at high pressure in the diamond anvil cell, which stimulated the theoretical and experimental investigations. To date, several hundred kinds of polymeric nitrogen have been reported. This review introduces the progressive development of polymeric nitrogen with high energy density, the challenges faced by the synthesized polymeric nitrogen under high-pressure,and the importance to improve the stability of polymeric nitrogen at ambient pressure. Furthermore, alternative methods for synthesizing polymeric nitrogen under moderate conditions are also presented. In this field, more efforts are needed to develop strategies for stabilizing more polymeric nitrogen to ambient conditions, especially the stability of free surfaces.
基金supported by the National Natural Science Foundation of China(32401919)the Department of Science and Technology of Henan Province(242102111126).
文摘Recent studies have shown that mucilage secretion from aerial roots is an essential feature of modern maize inbred lines,with some retaining the nitrogen-fixing capabilities of ancient landraces.To explore the genetic basis of nitrogen fixation in mucilage and its evolution from teosinte(Zea mays ssp.mexicana)to modern maize,we developed a recombinant inbred line(RIL)population from teosinte and cultivated it under low-nitrogen conditions.Large-scale,multi-year,and multi-environment analyses of RIL-Teo,Doubled Haploid-A(DH-A),Doubled Haploid-B(DH-B),and association populations led to the identification of 15 quantitative trait loci(QTL),68 quantitative trait nucleotides(QTN),and 59 candidate genes linked to mucilage secretion from aerial roots.Functional verification of the candidate gene ZmAco3,which is associated with mucilage secretion in aerial roots,demonstrated that deletion of this gene resulted in a reduction in mucilage secretion in aerial roots.In addition,most maize inbred lines exhibited stronger mucilage secretion from aerial roots under low-nitrogen conditions than under normal-nitrogen conditions.We categorized mucilage secretion into constitutive and low-nitrogen-inducible types.Through genotype-by-environment interaction studies,8 QTL,16 QTN,and 19 candidate genes were identified,revealing the genetic mechanisms underlying mucilage secretion under low-nitrogen conditions.These findings provide a comprehensive genetic analysis of the mucilage-secreting ability of maize aerial roots,contributing to our understanding of nitrogen fixation and offering potential avenues for enhancing nitrogen fixation in modern maize lines.This research advances knowledge of plant nutrient acquisition strategies and has implications for sustainable agricultural practices.
基金supported by the National Key Research and Development Program of China(No.2021YFC3201502)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX24_1830).
文摘Various forms of nitrogen(N)discharged by high-intensity human activities in the Yangtze River Delta are transported into the lake along the river channel,accelerating the lake’s N cycle and increasing the eutrophication ecological risk.Taihu Lake is a typical eutrophic shallowlake,suffering fromcyanobacteria blooms for decades due to excessive exogenous nutrient load.In this study,the coupling relationship between basin N loss and lake responsewas established by combining N flow and exogenous nutrient load.The results showed striking spatiotemporal differences and the large tributaries input themajority of N.Three evolution stages of the lake ecosystem were classified,i.e.,Stage A(1980–1997)with slow increasing N load;Stage B(1998–2006)with high-level N load despite some controlling methods;Stage C(2007 to present)with the strengthening of N management in lake basin after the Water Crisis,the N load has gradually decreased,while the water flow is increasing by the year.Environmental N export in the basin was 581.46 kg/ha N in 2021,and a total of 32.06 Gg N was finally drawn into the lake.Over the recent two decades,the noticeable expansion of built-up land from 8.21%to 21.04%associated with its environmental impacts i.e.,urban heat island effect,hard pavement,and ecological fragility deserves attention.Accordingly,the rapid climate change of the basin became the key factor driving the tributaries’hydrologic conditions(r_(∂)=0.945).The developed social economy dominated the sewage discharge(r_(∂)=0.857).The N inputs and losses to the environment in the basin can be further exacerbated without control.Meanwhile,the lake would respond to the exogenous input.In addition to the self-cleaning part of the lake,the N accumulation rate of the surface sediment ranged from 3.29 to 10.77 g N/(m^(2)·yr)of Taihu Lake.To meet the pollutant control target,around 66.28 Gg anthropogenic N needs to be reduced in the upper stream area yearly.Clarifying the N flow and its environmental burden can mitigate its damage to the ecosystem and take on the refined management on the watershed scale.
基金supported by the Bangladesh Agricultural Research Insti-tute,Gazipur-1701,Bangladesh.This research was also funded by Taif University,Saudi Arabia,Project No.(TU-DSPP-2024-07).
文摘The yield of maize(Zea mays L.)is highly influenced by nitrogen fertilization.This study investigated the impact of nitrogen fertilization on morphophysiological traits in maize(Zea mays L.)and developed algorithms to relate manual phenotyping and digital phenotyping of maize with leaf nitrogen and digital field image traits.The experiment included three hybrid maize varieties,V1(Hybrid 981),V2(BARI Hybrid maize-9),and V3(Hybrid P3396),which were evaluated across three nitrogen levels(N1=100 kg N ha^(−1),N2=200 kg N ha^(−1),N3=300 kg N ha^(−1))in a split-plot design with three replications.The results revealed that nitrogen levels(N),varieties(V),and their interactions(V×N)significantly influenced traits such as plant height(PH),leaf area index(LAI),normalized difference vegetation index(NDVI),canopy cover(CC),chlorophyll content(Chl a and Chl b),leaf nitrogen content(LNC),total dry matter(TDM),and grain yield.The hybrid P3396 with 300 kg N ha^(−1)(V3N3)achieved the highest grain yield of 14.45 t ha^(−1),which was statistically similar to that of Hybrid 981 and 300 kg N ha^(−1)(V1N3).Nitrogen significantly improved dry matter accumulation,leaf area,and physiological parameters,with maximum values recorded during flowering.The NDVI,CC,and SPAD were strongly correlated with LNC and TDM,highlighting their potential as indicators for nitrogen management.The digital imaging traits analysed via software effectively differentiated the nitrogen treatments,demonstrating their utility for precise nitrogen application.In conclusion,nitrogen fertilization at 300 kg N ha^(−1) optimized the growth and yield of hybrid maize,with Hybrid P3396 performing best.This study underscores the role of advanced phenotyping tools in improving nitrogen use efficiency and sustainable maize production.
基金supported by the grants from National Key Research and Development Program of China(2023YFD2303300)China Agriculture Research System(CARS-02-15)the Agricultural Science and Technology Innovation Program(CAAS-ZDRW202004).
文摘The unreasonable application of nitrogen fertilizer poses a threat to agricultural productivity and the environment protection in Northeast China.Therefore,accurately assessing crop nitrogen requirements and optimizing fertilization are crucial for sustainable agricultural production.A three-year field experiment was conducted to evaluate the effects of planting density on the critical nitrogen concentration dilution curve(CNDC)for spring maize under drip irrigation and fertilization integration,incorporating two planting densities:D1(60,000 plants ha^(-1))and D2(90,000 plants ha^(-1))and six nitrogen levels:no nitrogen(N0),90(N90),180(N180),270(N270),360(N360),and 450(N450)kg ha^(-1).A Bayesian hierarchical model was used to develop CNDC models based on dry matter(DM)and leaf area index(LAI).The results revealed that the critical nitrogen concentration exhibited a power function relationship with both DM and LAI,while planting density had no significant impact on the CNDC parameters.Based on these findings,we propose unified CNDC equations for maize under drip irrigation and fertilization integration:Nc=4.505DM-0.384(based on DM)and Nc=3.793LAI-0.327(based on LAI).Additionally,the nitrogen nutrition index(NNI),derived from the CNDC,increased with higher nitrogen application rates.The nitrogen nutrition index(NNI)approached 1 with a nitrogen application rate of 180 kg ha^(-1)under the D1 planting density,while it reached 1 at 270 kg ha^(-1)under the D2 planting density.The relationship between NNI and relative yield(RY)followed a“linear+plateau”model,with maximum RY observed when the NNI approached 1.Thus,under the condition of drip irrigation and fertilization integration in Northeast China’s spring maize production,the optimal nitrogen application rates for achieving the highest yields were 180 kg ha^(-1)at a planting density of 60,000 plants ha^(-1),and 270 kg ha^(-1)at a density of 90,000 plants ha^(-1).The CNDC and NNI models developed in this study are valuable tools for diagnosing nitrogen nutrition and guiding precise fertilization practices in maize production under integrated drip irrigation and fertilization systems in Northeast China.
基金supported by the National Natural Science Foundation of China(32160524)the National Key Research and Development Program of China(2022YFD1900200)+3 种基金the Industrial Support Project of Educational Committee of Gansu Province,China(2021CYZC-54)the China Agriculture Research System(CARS-22-G-12)the Fuxi Outstanding Talent Cultivation Program of Gansu Agricultural University,China(GAUfx-04J01)the“Innovation Star”Project of Gansu Province,China(2023CXZX-644)。
文摘The effcacy of integrating green manure in arid irrigation regions to enhance maize yield and nitrogen(N)uptake effciency has been extensively explored.However,limited research has delineated the contribution of green manure N vs.soil N on crop N utilization effciency.This study integrated feld experiments with micro-plot experiments to examine green manure(common vetch)management practices for achieving high maize yield and N uptake.In a micro-plot experiment,^(15)N technology was utilized to label green manure crops.Five treatments were applied in the research methodology:conventional tillage without green manure as the control(CT),tillage with total green manure incorporation(TG),no-tillage with total green manure mulching(NTG),tillage with only root incorporation(T),and no-tillage with removal of aboveground green manure(NT).The results of the micro-plot experiment were consistent with those observed in the feld,demonstrating that the utilization of green manure substantially increased maize yield and nitrogen uptake effciency(NUPE)compared to CT.In particular,under NTG,N uptake by maize from green manure was higher than NT and T,accounting for 59.1%of maize N uptake.Furthermore,applying NTG boosted the NUPE of soil N in maize to 50.7%,higher than TG by 5.5%.Meanwhile,it decreased the proportion of soil N in the maize.The difference between NTG and TG was primarily shown in the maize grains.For N transport in the soil,NTG decreased N loss while increasing soil N retention.Also,it facilitated the mineralization of soil organic N before the fowering stage.In conclusion,adopting no-tillage with total green manure mulching increased N uptake from green manure and the soil and decreased the proportion of soil-derived N in maize.
基金the financial support from the National Key Research and Development Program of China(2021YFA1501204)the project of SINOPEC RIPP Co.Ltd(PR20230230)。
文摘A comprehensive insight into the evolution and molecular structure of basic and neutral nitrogen compounds during the residue hydrotreating(RHT)process was gained through ESI(+)/ESI(-)FT-ICR MS analysis of the feedstock and its hydrogenated samples,with hydrodenitrogenation(HDN)ratios of 15.9%-70.1%.This study revealed that carbazoles,characterized by a double bond equivalent(DBE)of 9-11,were the refractory neutral nitrogen compounds during the RHT process.Their recalcitrant nature was primarily due to their low aromaticity and high steric hindrance.Conversely,quinolines(DBEs 7 to 9)were the most abundant basic nitrogen compounds.Through a meticulous analysis of DBE evolution,we revealed the intricate reaction mechanisms of benzocarbazoles and dibenzocarbazoles in residual oil,highlighting the crucial role of quinolines as key intermediates in eliminating these compounds.Interestingly,nitrogen compounds with either low or high carbon numbers(for a given DBE)exhibited higher reactivity than those with medium carbon numbers,which can be attributed to the low steric hindrance resulting from short alkyl chains and more naphthenic-aromatic structures,respectively.After hydrotreatment,the molecular structures of the most refractory or abundant nitrogen compounds could consist of two main types:those with multiple naphthenic-aromatic rings and those with long side chains near the nitrogen atom.This research has revealed nitrogen compounds'evolutionary mechanisms and refractory nature,and the molecular structure of the most resistant or abundant basic and neutral nitrogen compounds,providing a deeper understanding of the HDN process and ultimately paving the way for the rational RHT catalyst design and process development.
基金supported by the National Natural Science Foundation of China(Grant Nos.11974154,and 12304278)the Taishan Scholars Special Funding for Construction Projects(Grant No.tstp20230622)+1 种基金the Natural Science Foundation of Shandong Province(Grant Nos.ZR2022MA004,ZR2023QA127,and ZR2024QA121)the Special Foundation of Yantai for Leading Talents above Provincial Level。
文摘The four-decade quest for synthesizing ambient-stable polymeric nitrogen,a promising high-energy-density material,remains an unsolved challenge in materials science.We develop a multi-stage computational strategy employing density functional tight-binding-based rapid screening combined with density functional theory refinement and global structure searching,effectively bridging computational efficiency with quantum accuracy.This integrated approach identifies four novel polymeric nitrogen phases(Fddd,P3221,I4m2,and𝑃P6522)that are thermodynamically stable at ambient pressure.Remarkably,the helical𝑃6522 configuration demonstrates exceptional thermal resilience up to 1500 K,representing a predicted polymeric nitrogen structure that maintains stability under both atmospheric pressure and high-temperature extremes.Our methodology establishes a paradigm-shifting framework for the accelerated discovery of metastable energetic materials,resolving critical bottlenecks in theoretical predictions while providing experimentally actionable targets for polymeric nitrogen synthesis.
基金funded by UK Research and Innovation(UKRI)doctoral training grant no:BB/T008776/1the Department of Agriculture,Environment and Rural Affairs(DAERA)by Trouw Nutrition and by John Thompsons and Sons Ltd.
文摘Background Nitrogen-Use-Efficiency(NUE)in lactating dairy cows,defined as milk nitrogen(N)output as a proportion of N consumed,is low,with the majority of excess N excreted in manure.Excreted N can be lost to the environment as ammonia gas leading to environmental acidification and nutrient enrichment of sensitive habitats,and to watercourses contributing to aquatic eutrophication.While there is much evidence that NUE can be improved by reducing the crude protein(CP)content of dairy cow diets,the long-term impacts of feeding lower protein diets on cow performance and the rumen microbiome are less well understood.This study examined the effects of reducing the CP contents of dairy cow diets on cow performance,NUE,the relationship between NUE and residual feed intake(RFI),and the rumen microbiome.Results Dietary CP content did not affect feed intake,milk yield or milk composition(P>0.05),except for milk urea N(MUN),which increased with increasing diet CP content(P<0.05).The mean NUE was 34%,34%and 31%for the LCP(low-protein,15%),MCP(medium-protein,16%),and HCP(high-protein,17%)diets,respectively.RFI was negatively correlated with NUE(r=−0.57,P<0.001).The rumen ammonia-N concentrations increased with increasing dietary CP;however,the ruminal pH and volatile fatty acid(VFA)content of the rumen fluid remained constant.Predicted urinary N excretion was greater in the HCP and MCP diets than in the LCP diet.Reducing dietary CP content in dairy cow diets did not affect microbial composition,diversity and functional profiles.The family Bacteroidaceae was more abundant in HE(high-efficiency)cows,whereas the Methanobacteriaceae and the genus Methanobrevibacter were more abundant in LE(low-efficiency)cows.Additionally,propanoate metabolism,cysteine and methionine metabolism and amino acid biosynthesis pathways were more abundant in HE cows,whilst the methane(CH4)metabolism pathway was upregulated in LE cows.Conclusions The results demonstrate that diet CP can be reduced with no loss in cow performance,but with an associated reduction in N excretion.The abundance of microbial populations differed between low and high efficiency cows,which may contribute to the differences in efficiency observed.
基金the Fundamental Research Funds for the Central Universities(Grant No.2572021DT04)the National Natural Science Foundation of China(Grant No.31770656).
文摘Nitrogen and phosphorus (NP) deposition can change the nutrient input of forest ecosystems. The effects of NP deposition on soil aggregate need to be analyzed to propose effective environmental management strategies. In this study, representative Korean pine mixed forests and Korean pine plantations in northeastern China were selected. Soil samples were sieved to obtain four different particle sizes of soil aggregates (> 2, 2–0.25, 0.25–0.053, and < 0.053 mm). Four NP treatments were applied to simulate N and P deposition, and an indoor incubation experiment was conducted over a period of 360 d. Total nitrogen, microbial nitrogen, dissolved organic nitrogen, hydrolyzed nitrogen, NH_(4)^(+)–N, NO_(3)^(−)–N content, and extracellular enzyme activities of NAG, LAP, and AP were determined. Different fractions of N responded differently to NP addition. Lower NP addition had a greater promoting effect on aggregate N compared to higher NP addition. NAG was the main extracellular enzyme affecting N in both forest types. NP addition had a greater effect on the extracellular enzyme activities of the soil aggregates from the Korean pine plantations. These results enhance our understanding of the effects of NP addition on soil nitrogen within temperate forest ecosystems.
基金funded by the Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding,China(2021C02064-4)the Zhejiang Province“Three Rural and Nine Party”Science and Technology Cooperation Plan Project,China(2023SNJF002).
文摘Efficient nitrogen management is crucial for developing sustainable strategies aimed at enhancing yield while mitigating negative environmental impacts.However,research focusing on this aspect in the production of fresh maize is limited.Therefore,this study analyzed the effects of nitrogen application rates on the yields of 40 sweet and 44 waxy maize varieties at five sites in Zhejiang Province,China,from 2015 to 2019.The nitrogen application rates were categorized as either relatively high(RHN,>300 kg ha^(-1) for sweet maize and>320 kg ha^(-1) for waxy maize)or relatively low(RLN).An increase in nitrogen application rates significantly reduced nitrogen fertilizer partial productivity in both sweet and waxy maize(R^(2)=0.616,P<0.01;R^(2)=0.643,P<0.01),indicating that the optimum nitrogen application rates in this study might be the lowest values(160 kg ha^(-1) for sweet maize and 180 kg ha^(-1) for waxy maize).The kernel number per ear of sweet maize had a potentially more significant impact on fresh grain yield than the 1,000-fresh kernel weight under both RLN and RHN.In waxy maize,1,000-kernel weight contributed more to fresh grain yield under RLN,while kernel number per ear and 1,000-kernel weight cooperatively affected the yield under RHN.This study found that sweet maize required taller plant and ear heights,along with an optimal ear-plant height ratio,to enhance dry matter accumulation and increase source size,particularly under RLN,and to ultimately achieve a higher fresh grain yield.In contrast,a lower ear height and ear-plant height ratio in waxy maize probably contributed more to the greater kernel number and weight under RLN,likely due to a lower ear height which can reduce the distance between sink and source,enabling more efficient photoassimilate allocation to the ear.
