[Objective] This study aimed to explore an optimum application amount of nitrogen for cotton cultivation. [Method] In this study, a field experiment was conducted to investigate the effects of nitrogen application amo...[Objective] This study aimed to explore an optimum application amount of nitrogen for cotton cultivation. [Method] In this study, a field experiment was conducted to investigate the effects of nitrogen application amount on the growth characteristics, boll development and lint yield of high quality cotton line FZ-1. [Result] Compared with the nitrogen level of 225 kg/hm2, the lint yield had increased by 28.46% and 18.73%, respectively, with the nitrogen application amount of 300 and 375 kg/hm2. When the nitrogen application amount had increased from 225 to 300 kg/hm2, boll number per plant, boll weight and lint yield had significantly increased. At the nitrogen level of 375 kg/hm2, however, the effects of increasing lint yield were significantly less than that at the nitrogen level of 300 kg/hm2. Compared with the nitrogen levels of 225 and 375, 300 kg/hm2 of nitrogen was the optimum application amount to improve the plant height, daily increment of plant height, number of fruit branches, number ratio of nodes to fruit branches, boll volume and seed cotton weight per boll. [Conclusion] The rational management of nitrogen is the most effective way to promote the growth and development of cotton plants, ensure high yielding ability and minimize the environmental pollution caused by the overuse of nitrogen. This study had provided a sound nitrogen application strategy for the cultivation of this high-quality cotton line in the field plantation.展开更多
[ Objective] The aim of the research was to provide reference for reasonable application of nitrogen fertilizer for high yield.cultivation of hybrid rape cuhivar Youyan 9 and Youyan 10. [ Method] The net increment cha...[ Objective] The aim of the research was to provide reference for reasonable application of nitrogen fertilizer for high yield.cultivation of hybrid rape cuhivar Youyan 9 and Youyan 10. [ Method] The net increment changes of individual plant fresh weight and dry matter weight of Youyan 9 and Youyan 10 with different nitrogen application treatments were studied. [ Result] The differences among average fresh weight increments of individual plant and average dry matter weight increment of individual plant with different treatments reached 0. 01 extremely significant level. Fresh weight increment and dry matter weight net increment of individual plant declined gradually with the increase of nitrogen application. In growtheourse ,fresh weight net increment of individual plant increased firstly then decreased and the maximum was in beginning flowering stage, besides that dry matter net increment increased gradually and the maximum was in mature period. The correlations among fresh net increment, dry matter weight net increment and yield net increment were positive or extremely positive. [ Conclusion] Under experimental condition, when nitrogen application was 225 kg/hm^2, hybrid rape Yanyou 9 and Yanyou 10 with low erucic,low glucosinolate could obtain high yield.展开更多
[Objective] The paper was to study the nitrogen application amount and nitrogen application model for high grade hybrid rapeseed （Brassica napus L.） to get high yield. [Method] With ＂Youyan 599＂ and ＂Sanbei 98＂ ...[Objective] The paper was to study the nitrogen application amount and nitrogen application model for high grade hybrid rapeseed （Brassica napus L.） to get high yield. [Method] With ＂Youyan 599＂ and ＂Sanbei 98＂ as materials, using quadratic regression orthogonal gyration combination design, the impact of nitrogen application amount during various periods on rapeseed yield was studied. [Result] The combinations of factors to obtain the highest yield index （2 898.211 kg / hm 2 ） of ＂Youyan 599＂ were as follows： living rape fertilizer 89.27 kg / hm 2 , opening fertilizer 120 kg / hm 2 , 12 th lunar month fertilizer 101.12 kg / hm 2 , total nitrogen application amount 310.39 kg / hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12th lunar month fertilizer were 28.76%, 38.66% and 32.58%, respectively. The combinations of factors to obtain the highest yield index （2 870.14 kg/hm 2 ） of ＂Sanbei 98＂ were as follows： living rape fertilizer 120 kg / hm 2 , opening fertilizer 120 kg / hm 2 , 12 th lunar month fertilizer 37.55kg / hm 2 , total nitrogen application amount 277.55 kg / hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12 th lunar month fertilizer were 43.24%, 43.24% and 13.53%, respectively. The combinations of factors to obtain the highest yield index of two combined varieties （2 813.82 kg/hm 2 ）were as follows： living rape fertilizer 120 kg/hm 2 , opening fertilizer 120 kg/hm 2 , 12 th lunar month fertilizer 76.23 kg/hm 2 , total nitrogen application amount 316.23 kg/hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12 th lunar month fertilizer were 37.95% , 37.95% and 24.11% , respectively. [Conclusion] The paper provided theoretical basis for high yield cultivation of high grade hybridized rapeseed.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
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
Late sowing is a critical factor that hinders achieving high-yield,good-quality wheat under rice-wheat rotation.Understanding the physiological basis and regulatory pathways that lead to high yield and sound quality l...Late sowing is a critical factor that hinders achieving high-yield,good-quality wheat under rice-wheat rotation.Understanding the physiological basis and regulatory pathways that lead to high yield and sound quality late-sown wheat is crucial for developing effective cultivation strategies.A 2-year field experiment was conducted to investigate the effects of sowing date,nitrogen(N)application rate,and planting density on wheat yield,grain quality,population characteristics,and the underlying physiological factors.The results revealed significant interactions among the sowing date,planting density,and N application in regulating both yield and quality.Late sowing reduced grain yield primarily by reducing the number of spikes and kernels.However,the latter was improved by increasing N application and the planting density,thus mitigating the yield losses caused by late sowing.Moreover,the grain protein content(GPC)and wet gluten content(WGC)increased with delayed sowing dates and higher N rates but decreased with increased planting densities.For wheat yields over 9,000 or 7,500 kg ha^(-1),the latest sowing date should not be later than Nov.4 or 15,respectively.In addition,specific criteria should be met,including a maximum of 1.5 and 1.0 million stems and tillers ha^(-1),a maximum leaf area index of 6.7 and 5.5,and a dry matter accumulation(DMA)at anthesis of 14,000 and 12,000 kg ha^(-1),respectively.For high-yield,good-quality late-sown wheat,the optimal combination is a 25%increase in the N rate(300 kg N ha^(-1))and a planting density of 2.25 million(N300D225)or 3.75 million(N300D375)plants ha^(-1)for 10-or 20-day delays in sowing,respectively.These combinations result in a higher leaf net photosynthetic rate,higher activities of leaf nitrate reductase,glutamine synthetase,grain glutamic pyruvic transaminase,and a lower sugar-N ratio during post-anthesis.展开更多
The delayed nitrogen application technology is a crucial method for achieving high yield and efficiency in wheat cultivation.Specifically,more nitrogen is supplied to the middle and late growth stages of wheat by adju...The delayed nitrogen application technology is a crucial method for achieving high yield and efficiency in wheat cultivation.Specifically,more nitrogen is supplied to the middle and late growth stages of wheat by adjusting the application time and proportion of nitrogen fertilizer.This approach helps improve the tiller-bearing percentage and increase the number of grains per ear and the thousand-grain weight,while also reducing nitrogen loss and enhancing fertilizer use efficiency.This paper systematically elaborated on the high-yield and high-efficiency cultivation technology system with delayed nitrogen application for wheat,covering variety selection,soil management,sowing technology,the principle and implementation methods of delayed nitrogen application,integrated water and fertilizer management,field management,and comprehensive pest and disease control.Considering the ecological characteristics of major wheat-growing regions in China,tailored technical solutions were proposed,and operational key points of critical technological steps were introduced in detail.Through scientific variety distribution,precise nitrogen management,and integrated pest control,wheat yield and quality can be enhanced while achieving cost saving,improved efficiency,and ecological environmental protection.This paper provides systematic theoretical guidance and practical references for promoting thedelayed nitrogen application technology in wheat,thereby supporting the sustainable development of China s wheat industry.展开更多
Nitrogen deposition and water tables are important factors to control soil microbial community structure.However,the specific effects and mechanisms of nitrogen deposition and water tables coupling on bacterial divers...Nitrogen deposition and water tables are important factors to control soil microbial community structure.However,the specific effects and mechanisms of nitrogen deposition and water tables coupling on bacterial diversity,abundance,and community structure in arid alpine wetlands remain unclear.The nitrogen deposition(0,10,and 20 kg N/(hm^(2)•a))experiments were conducted in the Bayinbulak alpine wetland with different water tables(perennial flooding,seasonal waterlogging,and perennial drying).The 16S rRNA(ribosomal ribonucleic acid)gene sequencing technology was employed to analyze the changes in bacterial community diversity,network structure,and function in the soil.Results indicated that bacterial diversity was the highest under seasonal waterlogging condition.However,nitrogen deposition only affected the bacterial Chao1 and beta diversity indices under seasonal waterlogging condition.The abundance of bacterial communities under different water tables showed significant differences at the phylum and genus levels.The dominant phylum,Proteobacteria,was sensitive to soil moisture and its abundance decreased with decreasing water tables.Although nitrogen deposition led to changes in bacterial abundance,such changes were small compared with the effects of water tables.Nitrogen deposition with 10 kg N/(hm^(2)•a)decreased bacterial edge number,average path length,and robustness.However,perennial flooding and drying conditions could simply resist environmental changes caused by 20 kg N/(hm^(2)•a)nitrogen deposition and their network structure remain unchanged.The sulfur cycle function was dominant under perennial flooding condition,and carbon and nitrogen cycle functions were dominant under seasonal waterlogging and perennial drying conditions.Nitrogen application increased the potential function of part of nitrogen cycle and decreased the potential function of sulfur cycle in bacterial community.In summary,composition of bacterial community in the arid alpine wetland was determined by water tables,and diversity of bacterial community was inhibited by a lower water table.Effect of nitrogen deposition on bacterial community structure and function depended on water tables.展开更多
This study investigated the effect of magnesium application on peanut growth and yield under two nitrogen(N)application rates in acidic soil in southern China.The chlorophyll content,net photosynthetic rate and dry ma...This study investigated the effect of magnesium application on peanut growth and yield under two nitrogen(N)application rates in acidic soil in southern China.The chlorophyll content,net photosynthetic rate and dry matter accumulation of the N-sensitive cultivar decreased under reduced N treatments,whereas no effect was observed on the relevant indicators in the N-insensitive variety GH1026.Mg application increased the net photosynthetic rate by increasing the expression of genes involved in chlorophyll synthesis and Rubisco activity in the leaves during the pegging stage under 50%N treatment,while no effect on the net photosynthetic rate was observed under the 100%N treatment.The rate of dry matter accumulation at the early growth stage,total dry matter accumulation and pod yield at harvest increased after Mg application under 50%N treatment by increasing the transportation of assimilates from stems and leaves to pods in both peanut varieties,whereas no effect was found under 100%N treatment.Moreover,Mg application increased the NUE under 50%N treatment.No improvement of NUE in either peanut variety was found under 100%N treatment,while Mg application under the 50%N treatment can obtain a higher economic benefit than the 100%N treatment.In acidic soil,application of 307.5 kg ha^(-1)of Mg sulfate fertilizer under 50%reduced nitrogen application is a suitable fertilizer management measure for improving carbon assimilation,NUE and achieve high peanut yields in southern China.展开更多
In order to elucidate the response mechanism of yield and quality of different genotypes of foxtail millet to nitrogen application.In this study,plant physiology and metabolomics were used to study the effects of diff...In order to elucidate the response mechanism of yield and quality of different genotypes of foxtail millet to nitrogen application.In this study,plant physiology and metabolomics were used to study the effects of different amounts of nitrogen(0,75,150,225 and 300 kg hm^(-2))on agronomic characters,yield and quality of Jingu 21 and Zhangza 10.The results showed that with the increase of nitrogen application,the plant height of different genotypes of foxtail millet increased gradually,and the content of stem diameter,yield,protein,fat,lysine,phenylalanine,isoleucine,arginine,aspartic,glutamic,glycine,and proline content of different genotypes of foxtail millet showed an increasing and then decreasing trend.The highest yield was recorded in Jingu 21 at 150 kg hm^(-2),and the highest yield was recorded in Zhangza 10 at 225 kg hm^(-2) of nitrogen application.Yield of Jingu 21 was positively correlated with protein and tryptophan content(r=0.91).The yield of Zhangza 10 was positively correlated with fibre content(r=0.89).The protein content of different genotypes of foxtail millet were negatively correlated with the peak viscosity(PV),trough viscosity(TV)and breakdown value(BD).The results of this study clarify that the optimal nitrogen application of Jinguu 21 was 150 kg hm^(-2),and that of Zhangza 10 was 225 kg hm^(-2).The regulation effect of nitrogen on foxtail millet was clarified,which laid the theoretical and technical foundation for foxtail millet cultivation with high yield and high quality.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
Reducing nitrogen application rates can mitigate issues such as environmental degradation and resource wastage.However,it can also exacerbate problems such as wheat floret degeneration,leading to reduced yields.Theref...Reducing nitrogen application rates can mitigate issues such as environmental degradation and resource wastage.However,it can also exacerbate problems such as wheat floret degeneration,leading to reduced yields.Therefore,investigating wheat floret degeneration mechanisms under low-nitrogen stress and identifying mitigation measures are conducive to achieving high yields and sustainable development.To investigate the physiological mechanism of how low-nitrogen stress affects wheat floret degradation and whether exogenous brassinosteroids(BRs)can alleviate this stress,experiments were designed with treatments of three nitrogen application rates(N0,no nitrogen application;N1,120 kg ha–1 pure nitrogen;N2,240 kg ha–1 pure nitrogen)and exogenous spraying(N0CK,no nitrogen with water spraying;N0BR,no nitrogen with 24-epibrassinolide(an active brassinosteroid)spraying;N1,120 kg ha–1 pure nitrogen with water spraying).The results indicated that low-nitrogen stress generated a large amount of reactive oxygen species.Although wheat spikes synthesized flavonoids to combat oxidative stress,their energy metabolism(glycolysis and tricarboxylic acid cycle)and ascorbate-glutathione cycle were inhibited,which kept the reactive oxygen levels elevated within the spike,induced cell death and exacerbated floret degeneration.Furthermore,brassinosteroids played a role in regulating wheat floret degeneration under low-nitrogen stress.Exogenous foliar spraying of 24-epibrassinolide promoted energy metabolism and the ascorbate-glutathione cycle within the spike,which enhanced the energy charge and effectively mitigated a portion of the reactive oxygen induced by low-nitrogen stress,thereby alleviating the floret degeneration caused by low-nitrogen stress.In summary,low-nitrogen stress disrupts the redox homeostasis of wheat spikes,leading to floret degeneration,while brassinosteroids alleviate floret degeneration by improving the redox state of wheat spikes.This study provides theoretical support for balancing the contradiction between high yields and sustainable development and will be beneficial for the application of low nitrogen in production.展开更多
[Objective]The paper was to study the effect of different nitrogen application levels and modes on contents of different forms of nitrogen in rice plants.[Method] Using Guichao 2 and Diejiazhan as test materials,with ...[Objective]The paper was to study the effect of different nitrogen application levels and modes on contents of different forms of nitrogen in rice plants.[Method] Using Guichao 2 and Diejiazhan as test materials,with total nitrogen,protein nitrogen,chlorophyll nitrogen,soluble protein nitrogen,Rubisco nitrogen,free amino acid nitrogen as indicators,the effect of nitrogen application on contents of different forms of nitrogen in rice plants were studied.[Result] The contents of total nitrogen,protein nitrogen,chlorophyll nitrogen,soluble protein nitrogen,Rubisco-N,free amino nitrogen of rice plant during heading and maturity stage increased with the increasing application amount of nitrogen,and their contents would be high under heavy application of spike fertilizer when the application amount of nitrogen was the same.However,application of nitrogen had different impact on different forms of nitrogen,which showed obvious impact on the contents of Rubisco-N and free amino nitrogen.The differences of Rubisco-N and free amino nitrogen content of two varieties during heading and maturity stage under different nitrogen application modes all reached significant or extremely significant level.Correlation analysis showed that total nitrogen content of rice plant had extremely significant correlation with protein nitrogen content during heading and maturity stage in both early and late seasons.[Conclusion] The study provided a theoretical basis for clarifying the regulatory role of nitrogen application on nitrogen absorption and utilization.展开更多
[Objective] The study aimed at investigating the effects of different geographic sites,soil chemical characteristics and nitrogen application levels on nitrogen accumulation and distribution in different organs and ut...[Objective] The study aimed at investigating the effects of different geographic sites,soil chemical characteristics and nitrogen application levels on nitrogen accumulation and distribution in different organs and utilization efficiency for mid-season hybrid rice.[Method] By using mid-season rice varieties II-you 7 and Yuxiangyou203 as the experimental materials,field experiment was conducted at seven ecological sites in four provinces or cities in Southwestern China in 2009.A total of four nitrogen application levels were set as follows：by using 75 kg/hm2 of P2O5 and 75 kg/hm2 of K2O as the base fertilizer,extra 0,90,150 and 210 kg/hm2 of nitrogen fertilizer（in which,base fertilizer,base-tillering fertilizer and base-earing fertilizer respectively accounted for 60%,20% and 20%.） was applied,respectively.In the split-plot design,fertilizer was considered as the main factor while rice variety was taken as the secondary factor.A total of eight treatments were set with three replications.[Result] Highly significant differences of grain yield were found among seven locations,two varieties,four nitrogen application levels,interactions of site × variety and site × nitrogen application level,but the interaction of variety ×nitrogen application level had no significant influence on rice yield.There were highly significant effects of site,varieties and nitrogen application level on dry matter production,nitrogen content,nitrogen utilization efficiency.Highly significant negative correlations between uptake efficiency and utilization efficiency for nitrogen were found;and multiple stepwise regression analysis showed that nitrogen uptake-utilization efficiency were significantly influenced by different ecological sites,chemical quality of soil and the levels of nitrogen application.[Conclusion] The research will provide theoretical and practical basis for the highly efficient application of nitrogen in mid-season hybrid rice cultivation.展开更多
[Objective] This paper aimed at exploring the effects of different nitrogen application methods on the enzyme activities of leaves at ear position in late growth stage of maize. [Method] By pot experiment, the superox...[Objective] This paper aimed at exploring the effects of different nitrogen application methods on the enzyme activities of leaves at ear position in late growth stage of maize. [Method] By pot experiment, the superoxide dismutase （SOD） activity, peroxidase （POD） activity, malonyl dialdehyde （MDA） content and soluble protein content were determined. [Result] At the filling stage and ripening stage, with the increasing of nitrogen application rate, MDA content gradually decreased, while SOD activity, POD activity and soluble protein content increased. MDA content with two topdressing nitrogen was lower than that with one top dressing nitrogen at the same nitrogen application rate, while SOD activity, POD activity and soluble protein content with two topdressing nitrogen were higher than that with one topdressing nitrogen. [Conclusion] Different nitrogen application methods have relatively significant effects on the MDA content, SOD activity, POD activity and soluble protein content, which is of certain directive significance for preventing spring maize prematuration.展开更多
Nitrogen addition is rather important to the growth of alfalfa. In this study, the effects of different nitrogen application levels on various growth characteristics of alfalfa were investigated. The results showed th...Nitrogen addition is rather important to the growth of alfalfa. In this study, the effects of different nitrogen application levels on various growth characteristics of alfalfa were investigated. The results showed that nitrogen application exhibited no significant effects on plant height and stem diameter but posed significant effects on branch number of alfalfa. Branch number of alfalfa in each cutting raised with the increasing application level of nitrogen, with significant differences among different treatments （P〈0.05）; individual aboveground biomass increased with the increasing application level of nitrogen, but the increasing trend gradually tended to be steady from the first to the fourth cutting. Nitrogen application affected significantly （P〈0.05） individual aboveground biomass of alfalfa in the first, second and fourth cutting, but exhibited no significant effects on individual aboveground biomass of alfalfa in the third cutting. With the increase of nitrogen application level, total surface area, total volume, collar diameter and crossing number of alfalfa roots increased gradually, but total length, average diameter and furcating number of alfalfa roots increased first and then declined. Total length, average diameter and furcating number of alfalfa roots reached the maximum in N60 treatment.展开更多
Taking the flue-cured tobacco variety K326 as material, the research conducted field experiment to study the effects of quantity of nitrogen fertilizer and plant spacing on tobacco photosynthesis, dry matter accumulat...Taking the flue-cured tobacco variety K326 as material, the research conducted field experiment to study the effects of quantity of nitrogen fertilizer and plant spacing on tobacco photosynthesis, dry matter accumulation, yield and quality. The results showed that the CO2 concentration in the intercellular space was the highest in M2N2, and was the lowest M1N1, with extremely significant differences. The net photosynthetic rate was the highest in M2N2 and the lowest in M3N3. In resettling and squaring stages, with the same spacing, the weights of root dry matter were growing in different treatments upon nitrogen quantity; the weight of dry matter in stem showed irregularity; the dry matter of leaf accumulation kept slow in early and end stages, but fast in middle stage. In the same growth stage, dry matter accumulation of leaf was higher than those of stem and root, and the proportion of tobacco leaf to the whole plant was decreasing though always kept above 50%. In general, it can be concluded from yield, quality and output value that M2N2 performed the best.展开更多
[Objective] This study aimed to achieve high yield and stable yield of win- ter wheat-summer maize rotation system and provide basis for rational application of nitrogen fertilizer. [Method] Effects of continuous nitr...[Objective] This study aimed to achieve high yield and stable yield of win- ter wheat-summer maize rotation system and provide basis for rational application of nitrogen fertilizer. [Method] Effects of continuous nitrogen application on grain yield, economic profit, nitrogen uptake and utilization efficiency, and soil inorganic nitrogen accumulation in winter wheat-summer maize rotation system were investigated. [Re- sult] Nitrogen application could significantly increase the y（eld of the winter wheat- summer maize rotation system, which increased by 17.76%-30.32% and 22.24%- 46.63% in two rotation cycles, respectively. The yield of the winter wheat-summer maize rotation system was the maximum in two rotation cycles with nitrogen appli- cation amount of 660.0 kg/hm2, which reached respectively 23 391.19 and 23 444.35 kg/hm2, the yield and economic benefit were the highest, the nitrogen fertilizer use efficiency was 22.2% and 30.7%, the agronomic efficiency was 8.3 and 11.3 kg/kg. However, the nitrogen fertilizer use efficiency and agronomic efficiency between ni- trogen application amount of 540.0 and 660.0 kg/hm2 showed no significant differ- ence. After two rotation cycles, inorganic nitrogen accumulation in 0-40 cm soil with nitrogen application amount of 540.0 kg/hm2 was almost equal to that before experi- ment. [Conclusion] Under the experimental conditions, comprehensively considering the grain yield, economic profit, nitrogen fertilizer efficiency and soil inorganic nitro- gen balance, the optimal nitrogen application amount was 625.3-660.0 kg/hm2 in high-yield winter wheat-summer maize rotation system.展开更多
[Objective] This study aimed to determine the effects of supplemental irrigation on yield and nitrogen uptake in winter wheat. [Method] Three supplemental irrigation levels were set based on the target soil contents ...[Objective] This study aimed to determine the effects of supplemental irrigation on yield and nitrogen uptake in winter wheat. [Method] Three supplemental irrigation levels were set based on the target soil contents of 60%, 70% and 80%） at jointing stage of wheat. Moreover, three nitrogen levels （0, 195 and 255 kg/hm^2） were designed. The experimental plots were arranged fol owing a split-plot design. Zhoumai 18 was selected as the experimental material. [Result] Supplemental irrigation and nitrogen application in combination had significant or extremely significant effects on yield, yield components and nitrogen uptake in winter wheat. The interaction between irrigation and nitrogen fertilization had significant or extremely significant influence on the number of ears, number of grains per ear, 1 000-grain weight, grain yield and nitrogen accumulation in winter wheat. Under different combinations of supplemental irrigation and nitrogen application, the maximum yield of winter wheat was obtained at W2 N195, while the minimum at W1 N255. [Conclusion] With the increase of irrigation, negative effect of nitrogen on number of ears, number of grains per ear, 1 000-grain weight, grain yield and nitrogen accumulation decrease under lower nitrogen application rate.展开更多
Naked oat（Avena nuda L.） was originated from China,where soil nitrogen（N） is low availability.The responses of chlorophyll（Chl.） fluorescence parameters and leaf gas exchange to N application were analysed in th...Naked oat（Avena nuda L.） was originated from China,where soil nitrogen（N） is low availability.The responses of chlorophyll（Chl.） fluorescence parameters and leaf gas exchange to N application were analysed in this study.After the N application rate ranged from 60 to 120 kg ha-1,variable fluorescence（F v）,the maximal fluorescence（F m）,the maximal photochemical efficiency（F v /F m）,quantum yield（Φ PS II） of the photosynthetic system II（PS II）,electron transport rate（ETR）,and photochemical quenching coefficient（qP） increased with N application level,however,non-photochemical quenching coefficient（qN） decreased.Moreover,there was no difference in initial fluorescence（F o） with further more N enhancement.The maximum net photosynthetic rate（P max）,apparent dark respiration rate（R d） and light saturation point（LSP） were improved with 40-56 kg N ha-1as basal fertilizer and 24-40 kg N ha-1as top dressing fertilizer applied at jointing stage.Initial quantum yield（α） was decreased with 24 kg N ha-1as basal fertilizer and 56 kg N ha-1as top dressing fertilizer.Flag-leaf net photosynthetic rate（P n） was significantly enhanced at the jointing and heading stages with 40-56 kg N ha-1as basal fertilizer; in addition,increased at grain filling stage of naked oat with 40-56 kg N ha-1as top dressing fertilizer.90 kg N ha-1（50-70% as basal fertilizer and 30-50% as top dressing fertilizer） application is recommended to alleviate photodamage of photosystem and improve the photosynthetic rate in naked oat.展开更多
基金Supported by Natural Science Foundation of China(NSFC No.30771272,31171483)the Priority Academic Development Program of Jiangsu Higher Education Institutions+1 种基金Jiangsu Innovation Project for Agriculture Science and Technology(cx(11)2054)Jiangsu Agriculture Science and Technology Support Program(SBE2010307)~~
文摘[Objective] This study aimed to explore an optimum application amount of nitrogen for cotton cultivation. [Method] In this study, a field experiment was conducted to investigate the effects of nitrogen application amount on the growth characteristics, boll development and lint yield of high quality cotton line FZ-1. [Result] Compared with the nitrogen level of 225 kg/hm2, the lint yield had increased by 28.46% and 18.73%, respectively, with the nitrogen application amount of 300 and 375 kg/hm2. When the nitrogen application amount had increased from 225 to 300 kg/hm2, boll number per plant, boll weight and lint yield had significantly increased. At the nitrogen level of 375 kg/hm2, however, the effects of increasing lint yield were significantly less than that at the nitrogen level of 300 kg/hm2. Compared with the nitrogen levels of 225 and 375, 300 kg/hm2 of nitrogen was the optimum application amount to improve the plant height, daily increment of plant height, number of fruit branches, number ratio of nodes to fruit branches, boll volume and seed cotton weight per boll. [Conclusion] The rational management of nitrogen is the most effective way to promote the growth and development of cotton plants, ensure high yielding ability and minimize the environmental pollution caused by the overuse of nitrogen. This study had provided a sound nitrogen application strategy for the cultivation of this high-quality cotton line in the field plantation.
基金Funds for Transformation of Scientific and Technological Achievements of Ministry of Science and Technology of China (04EFN215200268)the Nomarch Special Foundation for the Excellent Science and Technology Talents of Guizhou Province[(2005(77)]the Science and Technology Program of Guizhou Province[(2006)6001]~~
文摘[ Objective] The aim of the research was to provide reference for reasonable application of nitrogen fertilizer for high yield.cultivation of hybrid rape cuhivar Youyan 9 and Youyan 10. [ Method] The net increment changes of individual plant fresh weight and dry matter weight of Youyan 9 and Youyan 10 with different nitrogen application treatments were studied. [ Result] The differences among average fresh weight increments of individual plant and average dry matter weight increment of individual plant with different treatments reached 0. 01 extremely significant level. Fresh weight increment and dry matter weight net increment of individual plant declined gradually with the increase of nitrogen application. In growtheourse ,fresh weight net increment of individual plant increased firstly then decreased and the maximum was in beginning flowering stage, besides that dry matter net increment increased gradually and the maximum was in mature period. The correlations among fresh net increment, dry matter weight net increment and yield net increment were positive or extremely positive. [ Conclusion] Under experimental condition, when nitrogen application was 225 kg/hm^2, hybrid rape Yanyou 9 and Yanyou 10 with low erucic,low glucosinolate could obtain high yield.
基金Supported by Construction Project of National Rapeseed Modern Industrial Technology System (nycytx-00563)Guizhou Academy of Agricultural Sciences "Research of High Yield and High Quality Cultivation Technology for High Grade Hybrid Rapeseed with High Oil" [C ZX(2007)015]+2 种基金Department of Agriculture of Guizhou Province "Research, Promotion and Application of High Yield Cultivation Technology for Hybridized Rapeseed of New Variety Youyan 599" [QNYZZ (2009) 007]Guizhou Academy of Agricultural Sciences "Large Area Intermediate Experiment, Promotion and Application of Hybridized Rapeseed Youyan 599" [QNKZX (2009) 030]Department of Agriculture of Guizhou Province "Integrated Innovation of Seed Production Techniques and Large Area Demonstration for New High Oil Rapeseed Hybrid Variety Sanbei 98 [QKH NY (2010) 3087]~~
文摘[Objective] The paper was to study the nitrogen application amount and nitrogen application model for high grade hybrid rapeseed （Brassica napus L.） to get high yield. [Method] With ＂Youyan 599＂ and ＂Sanbei 98＂ as materials, using quadratic regression orthogonal gyration combination design, the impact of nitrogen application amount during various periods on rapeseed yield was studied. [Result] The combinations of factors to obtain the highest yield index （2 898.211 kg / hm 2 ） of ＂Youyan 599＂ were as follows： living rape fertilizer 89.27 kg / hm 2 , opening fertilizer 120 kg / hm 2 , 12 th lunar month fertilizer 101.12 kg / hm 2 , total nitrogen application amount 310.39 kg / hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12th lunar month fertilizer were 28.76%, 38.66% and 32.58%, respectively. The combinations of factors to obtain the highest yield index （2 870.14 kg/hm 2 ） of ＂Sanbei 98＂ were as follows： living rape fertilizer 120 kg / hm 2 , opening fertilizer 120 kg / hm 2 , 12 th lunar month fertilizer 37.55kg / hm 2 , total nitrogen application amount 277.55 kg / hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12 th lunar month fertilizer were 43.24%, 43.24% and 13.53%, respectively. The combinations of factors to obtain the highest yield index of two combined varieties （2 813.82 kg/hm 2 ）were as follows： living rape fertilizer 120 kg/hm 2 , opening fertilizer 120 kg/hm 2 , 12 th lunar month fertilizer 76.23 kg/hm 2 , total nitrogen application amount 316.23 kg/hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12 th lunar month fertilizer were 37.95% , 37.95% and 24.11% , respectively. [Conclusion] The paper provided theoretical basis for high yield cultivation of high grade hybridized rapeseed.
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.
基金supported by the National Natural Science Foundation of China(32272215)the Key R&D Program of Jiangsu Province,China(BE2021361-1)the Collaborative Innovation Center for Modern Crop Production by Province and Ministry(CIC-MCP),Nanjing Agricultural University,China。
文摘Late sowing is a critical factor that hinders achieving high-yield,good-quality wheat under rice-wheat rotation.Understanding the physiological basis and regulatory pathways that lead to high yield and sound quality late-sown wheat is crucial for developing effective cultivation strategies.A 2-year field experiment was conducted to investigate the effects of sowing date,nitrogen(N)application rate,and planting density on wheat yield,grain quality,population characteristics,and the underlying physiological factors.The results revealed significant interactions among the sowing date,planting density,and N application in regulating both yield and quality.Late sowing reduced grain yield primarily by reducing the number of spikes and kernels.However,the latter was improved by increasing N application and the planting density,thus mitigating the yield losses caused by late sowing.Moreover,the grain protein content(GPC)and wet gluten content(WGC)increased with delayed sowing dates and higher N rates but decreased with increased planting densities.For wheat yields over 9,000 or 7,500 kg ha^(-1),the latest sowing date should not be later than Nov.4 or 15,respectively.In addition,specific criteria should be met,including a maximum of 1.5 and 1.0 million stems and tillers ha^(-1),a maximum leaf area index of 6.7 and 5.5,and a dry matter accumulation(DMA)at anthesis of 14,000 and 12,000 kg ha^(-1),respectively.For high-yield,good-quality late-sown wheat,the optimal combination is a 25%increase in the N rate(300 kg N ha^(-1))and a planting density of 2.25 million(N300D225)or 3.75 million(N300D375)plants ha^(-1)for 10-or 20-day delays in sowing,respectively.These combinations result in a higher leaf net photosynthetic rate,higher activities of leaf nitrate reductase,glutamine synthetase,grain glutamic pyruvic transaminase,and a lower sugar-N ratio during post-anthesis.
基金Supported by The Key Science and Technology Project of Shangqiu City(2024056).
文摘The delayed nitrogen application technology is a crucial method for achieving high yield and efficiency in wheat cultivation.Specifically,more nitrogen is supplied to the middle and late growth stages of wheat by adjusting the application time and proportion of nitrogen fertilizer.This approach helps improve the tiller-bearing percentage and increase the number of grains per ear and the thousand-grain weight,while also reducing nitrogen loss and enhancing fertilizer use efficiency.This paper systematically elaborated on the high-yield and high-efficiency cultivation technology system with delayed nitrogen application for wheat,covering variety selection,soil management,sowing technology,the principle and implementation methods of delayed nitrogen application,integrated water and fertilizer management,field management,and comprehensive pest and disease control.Considering the ecological characteristics of major wheat-growing regions in China,tailored technical solutions were proposed,and operational key points of critical technological steps were introduced in detail.Through scientific variety distribution,precise nitrogen management,and integrated pest control,wheat yield and quality can be enhanced while achieving cost saving,improved efficiency,and ecological environmental protection.This paper provides systematic theoretical guidance and practical references for promoting thedelayed nitrogen application technology in wheat,thereby supporting the sustainable development of China s wheat industry.
基金supported by the National Natural Science Foundation of China(31960258)the Graduate Research Innovation Project of Xinjiang Uygur Autonomous Region(XJ2023G119).
文摘Nitrogen deposition and water tables are important factors to control soil microbial community structure.However,the specific effects and mechanisms of nitrogen deposition and water tables coupling on bacterial diversity,abundance,and community structure in arid alpine wetlands remain unclear.The nitrogen deposition(0,10,and 20 kg N/(hm^(2)•a))experiments were conducted in the Bayinbulak alpine wetland with different water tables(perennial flooding,seasonal waterlogging,and perennial drying).The 16S rRNA(ribosomal ribonucleic acid)gene sequencing technology was employed to analyze the changes in bacterial community diversity,network structure,and function in the soil.Results indicated that bacterial diversity was the highest under seasonal waterlogging condition.However,nitrogen deposition only affected the bacterial Chao1 and beta diversity indices under seasonal waterlogging condition.The abundance of bacterial communities under different water tables showed significant differences at the phylum and genus levels.The dominant phylum,Proteobacteria,was sensitive to soil moisture and its abundance decreased with decreasing water tables.Although nitrogen deposition led to changes in bacterial abundance,such changes were small compared with the effects of water tables.Nitrogen deposition with 10 kg N/(hm^(2)•a)decreased bacterial edge number,average path length,and robustness.However,perennial flooding and drying conditions could simply resist environmental changes caused by 20 kg N/(hm^(2)•a)nitrogen deposition and their network structure remain unchanged.The sulfur cycle function was dominant under perennial flooding condition,and carbon and nitrogen cycle functions were dominant under seasonal waterlogging and perennial drying conditions.Nitrogen application increased the potential function of part of nitrogen cycle and decreased the potential function of sulfur cycle in bacterial community.In summary,composition of bacterial community in the arid alpine wetland was determined by water tables,and diversity of bacterial community was inhibited by a lower water table.Effect of nitrogen deposition on bacterial community structure and function depended on water tables.
基金supported by the Guangdong Technical System of Peanut and Soybean Industry(2023KJ136-05)China Agriculture Research System(CARS-15)。
文摘This study investigated the effect of magnesium application on peanut growth and yield under two nitrogen(N)application rates in acidic soil in southern China.The chlorophyll content,net photosynthetic rate and dry matter accumulation of the N-sensitive cultivar decreased under reduced N treatments,whereas no effect was observed on the relevant indicators in the N-insensitive variety GH1026.Mg application increased the net photosynthetic rate by increasing the expression of genes involved in chlorophyll synthesis and Rubisco activity in the leaves during the pegging stage under 50%N treatment,while no effect on the net photosynthetic rate was observed under the 100%N treatment.The rate of dry matter accumulation at the early growth stage,total dry matter accumulation and pod yield at harvest increased after Mg application under 50%N treatment by increasing the transportation of assimilates from stems and leaves to pods in both peanut varieties,whereas no effect was found under 100%N treatment.Moreover,Mg application increased the NUE under 50%N treatment.No improvement of NUE in either peanut variety was found under 100%N treatment,while Mg application under the 50%N treatment can obtain a higher economic benefit than the 100%N treatment.In acidic soil,application of 307.5 kg ha^(-1)of Mg sulfate fertilizer under 50%reduced nitrogen application is a suitable fertilizer management measure for improving carbon assimilation,NUE and achieve high peanut yields in southern China.
基金funded by the earmarked fund for CARS(CARS-06-14.5-A16)the Shanxi Provincial Key Research and Development Program(Program No.2022ZDYF110)+1 种基金the earmarked fund for Modern Agro-Industry Technology Research System(2024CYJSTX03-23)the Central Guided Local Science and Technology Development Funds(YDZJSX2022A044,YDZJSX20231A040).
文摘In order to elucidate the response mechanism of yield and quality of different genotypes of foxtail millet to nitrogen application.In this study,plant physiology and metabolomics were used to study the effects of different amounts of nitrogen(0,75,150,225 and 300 kg hm^(-2))on agronomic characters,yield and quality of Jingu 21 and Zhangza 10.The results showed that with the increase of nitrogen application,the plant height of different genotypes of foxtail millet increased gradually,and the content of stem diameter,yield,protein,fat,lysine,phenylalanine,isoleucine,arginine,aspartic,glutamic,glycine,and proline content of different genotypes of foxtail millet showed an increasing and then decreasing trend.The highest yield was recorded in Jingu 21 at 150 kg hm^(-2),and the highest yield was recorded in Zhangza 10 at 225 kg hm^(-2) of nitrogen application.Yield of Jingu 21 was positively correlated with protein and tryptophan content(r=0.91).The yield of Zhangza 10 was positively correlated with fibre content(r=0.89).The protein content of different genotypes of foxtail millet were negatively correlated with the peak viscosity(PV),trough viscosity(TV)and breakdown value(BD).The results of this study clarify that the optimal nitrogen application of Jinguu 21 was 150 kg hm^(-2),and that of Zhangza 10 was 225 kg hm^(-2).The regulation effect of nitrogen on foxtail millet was clarified,which laid the theoretical and technical foundation for foxtail millet cultivation with high yield and high quality.
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 Research and Development Program of Shaanxi,China(2021NY-083)the National Natural Science Foundation of China(31871567)。
文摘Reducing nitrogen application rates can mitigate issues such as environmental degradation and resource wastage.However,it can also exacerbate problems such as wheat floret degeneration,leading to reduced yields.Therefore,investigating wheat floret degeneration mechanisms under low-nitrogen stress and identifying mitigation measures are conducive to achieving high yields and sustainable development.To investigate the physiological mechanism of how low-nitrogen stress affects wheat floret degradation and whether exogenous brassinosteroids(BRs)can alleviate this stress,experiments were designed with treatments of three nitrogen application rates(N0,no nitrogen application;N1,120 kg ha–1 pure nitrogen;N2,240 kg ha–1 pure nitrogen)and exogenous spraying(N0CK,no nitrogen with water spraying;N0BR,no nitrogen with 24-epibrassinolide(an active brassinosteroid)spraying;N1,120 kg ha–1 pure nitrogen with water spraying).The results indicated that low-nitrogen stress generated a large amount of reactive oxygen species.Although wheat spikes synthesized flavonoids to combat oxidative stress,their energy metabolism(glycolysis and tricarboxylic acid cycle)and ascorbate-glutathione cycle were inhibited,which kept the reactive oxygen levels elevated within the spike,induced cell death and exacerbated floret degeneration.Furthermore,brassinosteroids played a role in regulating wheat floret degeneration under low-nitrogen stress.Exogenous foliar spraying of 24-epibrassinolide promoted energy metabolism and the ascorbate-glutathione cycle within the spike,which enhanced the energy charge and effectively mitigated a portion of the reactive oxygen induced by low-nitrogen stress,thereby alleviating the floret degeneration caused by low-nitrogen stress.In summary,low-nitrogen stress disrupts the redox homeostasis of wheat spikes,leading to floret degeneration,while brassinosteroids alleviate floret degeneration by improving the redox state of wheat spikes.This study provides theoretical support for balancing the contradiction between high yields and sustainable development and will be beneficial for the application of low nitrogen in production.
基金Supported by Natural Science Foundation of Guangxi Province(0728062)Natural Science Foundation of Guangxi Province(0832008Z)~~
文摘[Objective]The paper was to study the effect of different nitrogen application levels and modes on contents of different forms of nitrogen in rice plants.[Method] Using Guichao 2 and Diejiazhan as test materials,with total nitrogen,protein nitrogen,chlorophyll nitrogen,soluble protein nitrogen,Rubisco nitrogen,free amino acid nitrogen as indicators,the effect of nitrogen application on contents of different forms of nitrogen in rice plants were studied.[Result] The contents of total nitrogen,protein nitrogen,chlorophyll nitrogen,soluble protein nitrogen,Rubisco-N,free amino nitrogen of rice plant during heading and maturity stage increased with the increasing application amount of nitrogen,and their contents would be high under heavy application of spike fertilizer when the application amount of nitrogen was the same.However,application of nitrogen had different impact on different forms of nitrogen,which showed obvious impact on the contents of Rubisco-N and free amino nitrogen.The differences of Rubisco-N and free amino nitrogen content of two varieties during heading and maturity stage under different nitrogen application modes all reached significant or extremely significant level.Correlation analysis showed that total nitrogen content of rice plant had extremely significant correlation with protein nitrogen content during heading and maturity stage in both early and late seasons.[Conclusion] The study provided a theoretical basis for clarifying the regulatory role of nitrogen application on nitrogen absorption and utilization.
基金Supported by Construction of Southwestern Rice Innovation System,Science and Technology Project on Food Production (2006BAD02-A05)Agriculture Science Technology Achievement TransformationFund (2006GB2F000256)+2 种基金Sichuan Provincial Foundation for Lead-ers of Disciplines in ScienceProject of Rice Breeding Technology ofSichuanProgram Promoted by Sichuan Financial Administration~~
文摘[Objective] The study aimed at investigating the effects of different geographic sites,soil chemical characteristics and nitrogen application levels on nitrogen accumulation and distribution in different organs and utilization efficiency for mid-season hybrid rice.[Method] By using mid-season rice varieties II-you 7 and Yuxiangyou203 as the experimental materials,field experiment was conducted at seven ecological sites in four provinces or cities in Southwestern China in 2009.A total of four nitrogen application levels were set as follows：by using 75 kg/hm2 of P2O5 and 75 kg/hm2 of K2O as the base fertilizer,extra 0,90,150 and 210 kg/hm2 of nitrogen fertilizer（in which,base fertilizer,base-tillering fertilizer and base-earing fertilizer respectively accounted for 60%,20% and 20%.） was applied,respectively.In the split-plot design,fertilizer was considered as the main factor while rice variety was taken as the secondary factor.A total of eight treatments were set with three replications.[Result] Highly significant differences of grain yield were found among seven locations,two varieties,four nitrogen application levels,interactions of site × variety and site × nitrogen application level,but the interaction of variety ×nitrogen application level had no significant influence on rice yield.There were highly significant effects of site,varieties and nitrogen application level on dry matter production,nitrogen content,nitrogen utilization efficiency.Highly significant negative correlations between uptake efficiency and utilization efficiency for nitrogen were found;and multiple stepwise regression analysis showed that nitrogen uptake-utilization efficiency were significantly influenced by different ecological sites,chemical quality of soil and the levels of nitrogen application.[Conclusion] The research will provide theoretical and practical basis for the highly efficient application of nitrogen in mid-season hybrid rice cultivation.
基金Supported by National Science and Technology Support Program(2008BADA4B06,2011BAD16B12)International Plant Nutrition Institute (IPNI) Project~~
文摘[Objective] This paper aimed at exploring the effects of different nitrogen application methods on the enzyme activities of leaves at ear position in late growth stage of maize. [Method] By pot experiment, the superoxide dismutase （SOD） activity, peroxidase （POD） activity, malonyl dialdehyde （MDA） content and soluble protein content were determined. [Result] At the filling stage and ripening stage, with the increasing of nitrogen application rate, MDA content gradually decreased, while SOD activity, POD activity and soluble protein content increased. MDA content with two topdressing nitrogen was lower than that with one top dressing nitrogen at the same nitrogen application rate, while SOD activity, POD activity and soluble protein content with two topdressing nitrogen were higher than that with one topdressing nitrogen. [Conclusion] Different nitrogen application methods have relatively significant effects on the MDA content, SOD activity, POD activity and soluble protein content, which is of certain directive significance for preventing spring maize prematuration.
基金Supported by National Natural Science Foundation of China(Grant No.31372370)~~
文摘Nitrogen addition is rather important to the growth of alfalfa. In this study, the effects of different nitrogen application levels on various growth characteristics of alfalfa were investigated. The results showed that nitrogen application exhibited no significant effects on plant height and stem diameter but posed significant effects on branch number of alfalfa. Branch number of alfalfa in each cutting raised with the increasing application level of nitrogen, with significant differences among different treatments （P〈0.05）; individual aboveground biomass increased with the increasing application level of nitrogen, but the increasing trend gradually tended to be steady from the first to the fourth cutting. Nitrogen application affected significantly （P〈0.05） individual aboveground biomass of alfalfa in the first, second and fourth cutting, but exhibited no significant effects on individual aboveground biomass of alfalfa in the third cutting. With the increase of nitrogen application level, total surface area, total volume, collar diameter and crossing number of alfalfa roots increased gradually, but total length, average diameter and furcating number of alfalfa roots increased first and then declined. Total length, average diameter and furcating number of alfalfa roots reached the maximum in N60 treatment.
基金Supported by S&T Program of China Tobacco Jiangsu Industrial Co.,Ltd.(201101006)Jiangxi S&T Planning Program(20112BBF60001)~~
文摘Taking the flue-cured tobacco variety K326 as material, the research conducted field experiment to study the effects of quantity of nitrogen fertilizer and plant spacing on tobacco photosynthesis, dry matter accumulation, yield and quality. The results showed that the CO2 concentration in the intercellular space was the highest in M2N2, and was the lowest M1N1, with extremely significant differences. The net photosynthetic rate was the highest in M2N2 and the lowest in M3N3. In resettling and squaring stages, with the same spacing, the weights of root dry matter were growing in different treatments upon nitrogen quantity; the weight of dry matter in stem showed irregularity; the dry matter of leaf accumulation kept slow in early and end stages, but fast in middle stage. In the same growth stage, dry matter accumulation of leaf was higher than those of stem and root, and the proportion of tobacco leaf to the whole plant was decreasing though always kept above 50%. In general, it can be concluded from yield, quality and output value that M2N2 performed the best.
基金Supported by Science and Technology Project for Food Production(2011BAD16B15)"11th Five-Year Plan"National Science and Technology Support Program(2008-BADA4B07)Sino-International Plant Nutrition Research Institute(IPNI)Cooperation Project(NMBF-HenanAU-2008)~~
文摘[Objective] This study aimed to achieve high yield and stable yield of win- ter wheat-summer maize rotation system and provide basis for rational application of nitrogen fertilizer. [Method] Effects of continuous nitrogen application on grain yield, economic profit, nitrogen uptake and utilization efficiency, and soil inorganic nitrogen accumulation in winter wheat-summer maize rotation system were investigated. [Re- sult] Nitrogen application could significantly increase the y（eld of the winter wheat- summer maize rotation system, which increased by 17.76%-30.32% and 22.24%- 46.63% in two rotation cycles, respectively. The yield of the winter wheat-summer maize rotation system was the maximum in two rotation cycles with nitrogen appli- cation amount of 660.0 kg/hm2, which reached respectively 23 391.19 and 23 444.35 kg/hm2, the yield and economic benefit were the highest, the nitrogen fertilizer use efficiency was 22.2% and 30.7%, the agronomic efficiency was 8.3 and 11.3 kg/kg. However, the nitrogen fertilizer use efficiency and agronomic efficiency between ni- trogen application amount of 540.0 and 660.0 kg/hm2 showed no significant differ- ence. After two rotation cycles, inorganic nitrogen accumulation in 0-40 cm soil with nitrogen application amount of 540.0 kg/hm2 was almost equal to that before experi- ment. [Conclusion] Under the experimental conditions, comprehensively considering the grain yield, economic profit, nitrogen fertilizer efficiency and soil inorganic nitro- gen balance, the optimal nitrogen application amount was 625.3-660.0 kg/hm2 in high-yield winter wheat-summer maize rotation system.
基金Supported by the Water-and Fertilizer-saving Technology Demonstration for Wheat and Maize in Central Henan Province(2013BAD07B07-2)National Key Technology Research and Development Program during the 12th Five-year Plan Period(2012BAD04B07-2)~~
文摘[Objective] This study aimed to determine the effects of supplemental irrigation on yield and nitrogen uptake in winter wheat. [Method] Three supplemental irrigation levels were set based on the target soil contents of 60%, 70% and 80%） at jointing stage of wheat. Moreover, three nitrogen levels （0, 195 and 255 kg/hm^2） were designed. The experimental plots were arranged fol owing a split-plot design. Zhoumai 18 was selected as the experimental material. [Result] Supplemental irrigation and nitrogen application in combination had significant or extremely significant effects on yield, yield components and nitrogen uptake in winter wheat. The interaction between irrigation and nitrogen fertilization had significant or extremely significant influence on the number of ears, number of grains per ear, 1 000-grain weight, grain yield and nitrogen accumulation in winter wheat. Under different combinations of supplemental irrigation and nitrogen application, the maximum yield of winter wheat was obtained at W2 N195, while the minimum at W1 N255. [Conclusion] With the increase of irrigation, negative effect of nitrogen on number of ears, number of grains per ear, 1 000-grain weight, grain yield and nitrogen accumulation decrease under lower nitrogen application rate.
基金the study grants from the Special Fund for Agro-Scientific Research in the Public Interest,China(nyhyzx07-009-2)the Earmarked Fund for China Agriculture Research System(CARS-08-B-1)
文摘Naked oat（Avena nuda L.） was originated from China,where soil nitrogen（N） is low availability.The responses of chlorophyll（Chl.） fluorescence parameters and leaf gas exchange to N application were analysed in this study.After the N application rate ranged from 60 to 120 kg ha-1,variable fluorescence（F v）,the maximal fluorescence（F m）,the maximal photochemical efficiency（F v /F m）,quantum yield（Φ PS II） of the photosynthetic system II（PS II）,electron transport rate（ETR）,and photochemical quenching coefficient（qP） increased with N application level,however,non-photochemical quenching coefficient（qN） decreased.Moreover,there was no difference in initial fluorescence（F o） with further more N enhancement.The maximum net photosynthetic rate（P max）,apparent dark respiration rate（R d） and light saturation point（LSP） were improved with 40-56 kg N ha-1as basal fertilizer and 24-40 kg N ha-1as top dressing fertilizer applied at jointing stage.Initial quantum yield（α） was decreased with 24 kg N ha-1as basal fertilizer and 56 kg N ha-1as top dressing fertilizer.Flag-leaf net photosynthetic rate（P n） was significantly enhanced at the jointing and heading stages with 40-56 kg N ha-1as basal fertilizer; in addition,increased at grain filling stage of naked oat with 40-56 kg N ha-1as top dressing fertilizer.90 kg N ha-1（50-70% as basal fertilizer and 30-50% as top dressing fertilizer） application is recommended to alleviate photodamage of photosystem and improve the photosynthetic rate in naked oat.
