Using hybrid rice Shanyou63, the agronomic and economic characters of different nitrogen(N) managements were evaluated. The results showed that the grain yield of the control(N omission plots) ranged from 6.8 to 7.4 t...Using hybrid rice Shanyou63, the agronomic and economic characters of different nitrogen(N) managements were evaluated. The results showed that the grain yield of the control(N omission plots) ranged from 6.8 to 7.4 t ha-1, indicating the high indigenous N supplyof the soil. Compared with farmers fertilizer practice (FFP, 240 kg N ha-1), the modifiedFFP (70% N of FFP), real-time N management (RTNM, applying N based on values ofchlorophyll meter) and site-specific N management (SSNM, applying nitrogen based on thetiming, amount of N and values of chlorophyll meter) increased the grain yield by 9.2-10.3%, 3.3-7.0% and 8.9-9.3%, and agronomic N efficiency (the increase in grain yieldper unit N applied) by 110.5-135.6%, 204.3-297.0% and 200.9-276.4%, respectively. Theresults suggested that RTNM and SSNM have great potential for improving N use efficiencywithout sacrificing the grain yield. In addition, RTNM and SSNM also decreased chalkygrain percentage and chalkiness to improve grain appearance quality.展开更多
Knowledge about crop growth processes in relation to N limitation is necessary to optimize N management in farming system. Plant-based diagnostic method, for instance nitrogen nutrition index （NNI） were used to dete...Knowledge about crop growth processes in relation to N limitation is necessary to optimize N management in farming system. Plant-based diagnostic method, for instance nitrogen nutrition index （NNI） were used to determine the crop nitrogen status. This study determines the relationship of NNI with agronomic nitrogen use efficiency （AEN）, tuber yield, radiation use efficiency （RUE） and leaf parameters including leaf area index （LAI）, areal leaf N content （NJ and leaf N concentration （N0. Potatoes were grown in field at three N levels： no N （N 1）, 150 kg N ha^-1 （N2）, 300 kg N ha^-1 （N3）. N deficiency was quantified by NNI and RUE was generally calculated by estimating of the light absorbance on leaf area. NNI was used to evaluate the N effect on tuber yield, RUE, LAI, NAL, and NL. The results showed that NNI was negatively correlated with AEN, N deficiencies （NNI〈 1） which occurred for N 1 and N2 significantly reduced LAI, NL and tuber yield; whereas the N deficiencies had a relative small effect on NAL and RUE. To remove any effect other than N on these parameters, the actual ratio to maximum values were calculated for each developmental linear relationships were obtained between NNI and tuber RUE to NNI. stage of potatoes. When the NNI ranged from 0.4 to 1, positive yield, LAI, NL, while a nonlinear regression fitted the response of展开更多
Rational application of different forms of nitrogen（N） fertilizer for peanut（Arachis hypogaea L.） requires tracking the N supplied sources which are commonly not available in the differences among the three source...Rational application of different forms of nitrogen（N） fertilizer for peanut（Arachis hypogaea L.） requires tracking the N supplied sources which are commonly not available in the differences among the three sources：root nodule,soil and fertilizer.In this study,two kinds of peanut plants（nodulated variety（Huayu 22） and non-nodulated variety（NN-1）） were choosed and four kinds of N fertilizers：urea-N（CONH_2-N）,ammonium-N（NH_4~＋-N）,nitrate-N（NO_3^--N） and NH_4~＋ ＋NO_3^--N labeled by^（15）N isotope were applied in the field barrel experiment in Chengyang Experimental Station,Shandong Province,China,to determine the N supplied sources and N use efficiency over peanut growing stages.The results showed that intensities and amounts of N supply from the three sources were all higher at middle growing stages（pegging phase and podding phase）.The accumulated amounts of N supply from root nodule,soil and fertilizer over the growing stages were 8.3,5.3 and 3.8g m^（-2） in CONH_2-N treatment,which are all significantly higher than in the other three treatments.At seedling phase,soil supplied the most N for peanut growth,then root nodule controlled the N supply at pegging phase and podding phase,but soil mainly provided N again at the last stage（pod filling phase）.For the whole growing stages,root nodule supplied the most N（47.8 and 43.0%） in CONH_2-N and NH_4~＋-N treatments,whereas soil supplied the most N（41.7 and 40.9%） in NH_4~＋ ＋NO_3^--N and NO_3^--N treatments.The N use efficiency was higher at pegging phase and podding phase,while accumulated N use efficiency over the growing stages was higher in CONH_2-N treatment（42.2%） than in other three treatments（30.4%in NH_4~＋-N treatment,29.4%in NO_3^--N treatment,29.4%in NH_4~＋ ＋NO_3^--N treatment）.In peanut growing field,application of CONH_2-N is a better way to increase the supply of N from root nodule and improve the N use efficiency.展开更多
In order to investigate effects of topdressing on grain yield and N use efficiency of mechanically-transplanted hybrid rice, this experiment was conducted with 2-line hybrid rice cultivars, Quaniiangyou 1 and Quanlian...In order to investigate effects of topdressing on grain yield and N use efficiency of mechanically-transplanted hybrid rice, this experiment was conducted with 2-line hybrid rice cultivars, Quaniiangyou 1 and Quanliangyou 681 with 3 application levels of N fertilizer, No, N1, N2, respectively. The results showed that there were no significant differences in grain yields of the 2 varieties between treatments N1 and N2. It was indicated that N is not the factor which could limit grain yield within limited application levels of N fertilizer. High N fertilizer treatment could contribute to the formation of effective panicles and spikelets per panicle, but it could also lead to the decline in grain filling rate. It was suggested that lowering the amount of Nfertilizer could facilitate improvement of N-use efficiency.展开更多
Aligning leaf nitrogen(N) distribution to match the light gradient is crucial for maximizing canopy dry matter production(DMP) and improving N utilization efficiency. However, the relationship between the gradient of ...Aligning leaf nitrogen(N) distribution to match the light gradient is crucial for maximizing canopy dry matter production(DMP) and improving N utilization efficiency. However, the relationship between the gradient of root-derived cytokinins and N distribution in rice leaves and its impact on DMP and the underlying mechanisms remains poorly understood. A two-year field experiment was conducted using two japonica N-efficient varieties(NEVs) and two japonica N-inefficient varieties(NIVs) under four different N rates(0, 90, 180, and 360 kg N ha^(-1)). These selected varieties exhibited similar values in the coefficient of light extinction(K_(L)). Results showed that at lower N rates(0–180 kg N ha^(-1)), the NEVs exhibited greater dry matter weight at maturity, higher grain yield, and improved internal N use efficiency(IE_(N)) compared to the NIVs, despite possessing comparable total N uptake. Compared with the NIVs, the NEVs exhibited a more pronounced nitrogen distribution gradient in leaves, as indicated by the coefficient of nitrogen extinction(K_(N)) values during the middle and early grain-filling stages. This enhanced gradient led to improved coordination between light and nitrogen, resulting in greater photosynthetic production, particularly at lower N rates. Furthermore, the NEVs demonstrated a larger gradient of zeatin(Z)+zeatin riboside(ZR) in leaves(i.e., higher ratios of Z+ZR levels between upper and lower leaves), enhanced expression levels of genes related to N export in lower leaves and Z+ZR loading in the root, respectively, elevated enzymes activities related to N assimilation in upper leaves, in relative to the NIVs. Correlation and random forest analyses demonstrated a strong positive correlation between the Z+ZR gradient, K_(N), and DMP, and the gradient facilitated the export of N from lower leaves and its assimilation in upper leaves, contributing significantly to both K_(N) and DMP. This process was closely linked to root activity, including root oxidation activity, root Z+ZR content, and Z+ZR loading capacity, as confirmed by applying an inhibitor or a promoter of cytokinins biosynthesis to roots. Interestingly, at the N rate of 360 kg N ha^(-1), both NEVs and NIVs showed indistinguishable plant traits, achieving a super high-yielding level(over 10.5 t ha^(-1)) but with remarkably low IE_(N). The results suggest that increasing the Z+ZR gradient can improve K_(N) and DMP, where it needs to maintain higher root activity, thus leading to high yield and high IE_(N). Further research is needed to explore and develop cultivation practices with reduced N to unlock the super-high-yielding potential of the NEVs.展开更多
Nitrogen(N)serves as an essential nutrient for yield formation across diverse crop types.However,agricultural production encounters numerous challenges,notably high N fertilizer rates coupled with low N use efficiency...Nitrogen(N)serves as an essential nutrient for yield formation across diverse crop types.However,agricultural production encounters numerous challenges,notably high N fertilizer rates coupled with low N use efficiency and serious environmental pollution.Deep placement of nitrogen fertilizer(DPNF)is an agronomic measure that shows promise in addressing these issues.This review aims to offer a comprehensive understanding of DPNF,beginning with a succinct overview of its development and methodologies for implementation.Subsequently,the optimal fertilization depth and influencing factors for different crops are analyzed and discussed.Additionally,it investigates the regulation and mechanism underlying the DPNF on crop development,yield,N use efficiency and greenhouse gas emissions.Finally,the review delineates the limitations and challenges of this technology and provides suggestions for its improvement and application.This review provides valuable insight and reference for the promotion and adoption of DPNF in agricultural practice.展开更多
[Objective] The aim was to explore effects of application postponing of N fertilizer and the mechanism of yield increase in order to provide references for N fertilizer application in a rational way. [Method] In a sup...[Objective] The aim was to explore effects of application postponing of N fertilizer and the mechanism of yield increase in order to provide references for N fertilizer application in a rational way. [Method] In a super-high yielded region of summer maize, field experiment was conducted to research effects of N fertilizer postponing on key enzymes of N metabolism, yield of maize and N fertilizer use. [Result] After application of N fertilizer was postponed, NR, SPS and GS activities of ear-leaf of summer maize increased by 11.99%-34.87%, 8.25%-10.64% and 10.00%- 16.81% on the 28^th d of silking; content of soluble sugar in leaves enhanced signifi- cantly and accumulated nitrogen increased by 5.00%-9.74% in mature stage. The postponing fertilization of ＂30% of fertilizer in seedling stage＋30% of fertilizer in flare- opening stage＋40% of fertilizer in silking stage meets N demands of summer maize in late growth period. Compared with conventional fertilization, the maize yield, agro- nomic efficiency and use of N fertilizer all improved by 5.05%, 1.75 kg/kg and 6.87%, respectively, after application postponed. [Conclusion] Application postponing of N fertilizer maintains activity of NR, GS and SPS higher and coordinates metabolism of C and N in late growth period, to further improve yield of maize.展开更多
High rates of fertilizer nitrogen (N) are applied in greenhouse vegetable fields in southeastern China to maximize production;however,the N budgets of such intensive vegetable production remain to be explored.The goal...High rates of fertilizer nitrogen (N) are applied in greenhouse vegetable fields in southeastern China to maximize production;however,the N budgets of such intensive vegetable production remain to be explored.The goal of this study was to determine the annual N balance and loss in a greenhouse vegetable system of annual rotation of tomato,cucumber,and celery at five N (urea) application rates (0,348,522,696,and 870 kg N ha-1 year-1).Total N input to the 0-50 cm soil layer ranged from 531 to 1 053 kg ha-1,and N fertilizer was the main N source,accounting for 66%-83% of the total annual N input.In comparison,irrigation water,wet deposition,and seeds in total accounted for less than 1% of the total N input.The fertilizer N use efficiency was only 18% under the conventional application rate of 870 kg N ha-1 and decreased as the application rate increased from 522 to 870 kg N ha-1.Apparent N losses were 196-201 kg N ha-1,of which 71%-86% was lost by leaching at the application rates of 522-870 kg N ha-1.Thus,leaching was the primary N loss pathway at high N application rates and the amount of N leached was proportional to the N applied during the cucumber season.Moreover,dissolved organic N accounted for 10% of the leached N,whereas NH3 volatilization only contributed 0.1%-0.6% of the apparent N losses under the five N application rates in this greenhouse vegetable system.展开更多
The objective is to study whether the accumulation and utilization of plant N are controlled by Mo status in winter wheat cultivars. Mo-efficient cultivar 97003 （eft） and Mo-inefficient cultivar 97014 （ineff） were...The objective is to study whether the accumulation and utilization of plant N are controlled by Mo status in winter wheat cultivars. Mo-efficient cultivar 97003 （eft） and Mo-inefficient cultivar 97014 （ineff） were grown in severely Mo-deficient acidic soil （Tamm-reagent-extractable Mo 0.112 mg kg^-1） with （＋Mo） and without （-Mo） the application of 0.13 mg kg^-1 Mo. The accumulation and use efficiency of plant total N were significantly higher in ＋Mo than that in -Mo and in eft than that in ineff under Mo deficiency. N use efficiency was remarkably higher in maturity but it was forwarded to jointing stage after Mo supply, thus indicating that Mo supply promoted the N use efficiency besides N uptake and eff was efficient in N uptake and utilization. The overall activity of nitrate reductase （NR, EC 1.6.6.1） was significantly higher in ＋Mo than in -Mo and ratio of ＋Mo/-Mo was even to 14.8 at filleting stage for ineff. Activity of glutamine synthetase （GS, EC 6.3.1.2） was significantly lower in ＋Mo than in -Mo. Concentration of nitrate and glutamate were also significantly lower in ＋Mo than in -Mo, thus provided evidences for enhancing N use efficiency by Mo supply. Activities of NR and GS were significantly higher and concentrations of nitrate and glutamate were significantly lower in eff than ineff under Mo deficiency, thus indicated eff was more efficient in N reduction and utilization. It is therefore concluded that Mo could promote N accumulation and utilization in winter wheat which was directly related to NR and feedback regulated by GS. Higher Mo status also results in higher accumulation and utilization of plant N in eft.展开更多
Due to the relatively late start of organic rice(Oryza sativa L.) research in China,there is a still lack of systematic research on rice varieties,organic fertilizer management practices,and especially the mechanisms ...Due to the relatively late start of organic rice(Oryza sativa L.) research in China,there is a still lack of systematic research on rice varieties,organic fertilizer management practices,and especially the mechanisms of nitrogen(N) uptake and utilization.Three rice varieties,Nanjing 5055,Nanjing 9108,and Nanjing 46,were grown under organic farming(OF) at three organic fertilizer levels(103.2,160.8,and 218.4 kg N ha^(-1)) and conventional farming(CF) with regular chemical fertilizers.Rice grain yields,yield components,and quality,dry matter accumulation,and plant N were measured at different growth stages during the 2012 and 2013 growing seasons.Compared with CF,OF had a significantly reduced yield.Nanjing 9108 showed significant reductions in number of panicles per unit area and percentage of filled grains,and had the lowest yield.The effects of fertilizer type and application rate on dry matter accumulation during the main growth periods were significant for all varieties.The N content and uptake in organically grown rice were lower compared with those of rice under CF.The N recovery efficiency and N agronomic efficiency were significantly lower,whereas N physiological efficiency and N partial factor productivity were greater under OF than under CF.Under OF,the processing quality showed a slight but insignificant decline,protein content and gel consistency increased,and amylose content decreased compared with those under CF.Correlation analysis showed that under OF,grain yield was significantly correlated with N uptake.The medium organic fertilizer level(160.8 kg N ha^(-1)) was found to be the optimum fertilizer treatment,and Nanjing 46 appeared to be the best variety for organic rice cultivation.To increase rice grain yields and reduce the potential risk of non-point source pollution in organic agriculture,further research is needed to improve the N use efficiency in organic rice cultivation.展开更多
Fertilizers contribute greatly to high yields but also result in environmental non-point contamination, including the emission of greenhouse gas(N 2O) and eutrophication of water bodies. How to solve this problem has...Fertilizers contribute greatly to high yields but also result in environmental non-point contamination, including the emission of greenhouse gas(N 2O) and eutrophication of water bodies. How to solve this problem has become a serious challenge, especially for China as its high ecological pressure. Controlled-release fertilizer(CRF) has been developed to minimize the contamination while keeping high yield and has become a green fertilizer for agriculture. Several CRFs made with special coating technology were used for testing the fertilizer effects in yield and environment through pot experiment and field trial. The result indicated that the CRFs had higher N use efficiency, thus reducing N loss through leaching and volatilization while keeping higher yields. Comparing with imported standard CRFs, the test on CRFs showed similar fertilizer effect but with much lower cost. CRFs application is becoming a new approach for minimizing non-point contamination in agriculture.展开更多
Planting at an optimum density and supplying adequate nitrogen（N） to achieve higher yields is a common practice in crop production, especially for maize（Zea mays L.）; however, excessive N fertilizer supply in maiz...Planting at an optimum density and supplying adequate nitrogen（N） to achieve higher yields is a common practice in crop production, especially for maize（Zea mays L.）; however, excessive N fertilizer supply in maize production results in reduced N use efficiency（NUE） and severe negative impacts on the environment. This research was conducted to determine the effects of increased plant density and reduced N rate on grain yield, total N uptake, NUE, leaf area index（LAI）, intercepted photosynthetically active radiation（IPAR）, and resource use efficiency in maize. Field experiments were conducted using a popular maize hybrid Zhengdan 958（ZD958） under different combinations of plant densities and N rates to determine an effective approach for maize production with high yield and high resource use efficiency. Increasing plant density was clearly able to promote N absorption and LAI during the entire growth stage, which allowed high total N uptake and interception of radiation to achieve high dry matter accumulation（DMA）, grain yield, NUE, and radiation use efficiency（RUE）. However, with an increase in plant density, the demand of N increased along with grain yield. Increasing N rate can significantly increase the DMA, grain yield, LAI, IPAR, and RUE. However, this increase was non-linear and due to the input of too much N fertilizers, the efficiency of N use at NCK（320 kg ha^（–1）） was low. An appropriate reduction in N rate can therefore lead to higher NUE despite a slight loss in grain production. Taking into account both the need for high grain yield and resource use efficiency, a 30% reduction in N supply, and an increase in plant density of 3 plants m^（–2）, compared to LD（5.25 plants m^（–2））, would lead to an optimal balance between yield and resource use efficiency.展开更多
As a result of intensive greenhouse vegetable production in northern China, the potential risk of nitrogen （N） fertilizer over-applied is increasingly apparent and is threatening ecosystem and the sustainability of ...As a result of intensive greenhouse vegetable production in northern China, the potential risk of nitrogen （N） fertilizer over-applied is increasingly apparent and is threatening ecosystem and the sustainability of food production. An experiment was carried out in Shouguang, Shangdong Province, China to evaluate agronomic benefit and soil quality under different N applications, including the conventional chemical N rate （1000 kg N ha^（-1） season^（-1）, N1）, 70% of N1 （N2）, 70% of N1 ＋ maize straw （N3）, 50% of N1 ＋ maize straw ＋ drip irrigation （N4）, and 0% of N1 （NO）, during two successive growing seasons of autumn-winter （AW） and winter-spring （WS）. The maximum yields for N4 were 1.1 and 1.0 times greater than those for N1 in the AW and WS seasons, respectively. N agronomic efficiency （AEN） and apparent N recovery efficiency （REN） were greatest with the N4. A significant relationship was found between soil NO3-N content and electrical conductivity （EC） （R^2 = 0.61 in the AW season and R^2= 0.29 in the WS season）. Reducing N fertilizer decreased soil NO3-N accumulation （20.9%-37.8% reduction in the AW season and 11.7%-20.1% reduction in the WS season） relative to the accumulation observed for N1 within the 0-100 cm soil layer. Soil urease and invertase activities were not significantly different among N treatments. The N4 treatment would be practical for reducing excess N input and maintaining the sustainability of greenhouse-based intensive vegetable systems in Shouguang.展开更多
The effects of yield increase and mechanism of site-specific nitrogen management （SSNM） in five rice varieties from cold areas of northeastern China were studied. Plot experiment for critical SPAD value and experime...The effects of yield increase and mechanism of site-specific nitrogen management （SSNM） in five rice varieties from cold areas of northeastern China were studied. Plot experiment for critical SPAD value and experiments of two fertilization methods, SSNM and farmer＇s fertilization practice （FFP） were conducted to study their effects on the quality and dry matter accumulation of rice population, as well as N uptake. Compared with FFP, SSNM significantly decreased the average N rate by 33.8%, significantly increased average ear-bearing tiller rate and LAI for grain-filling stage by 12.3% and 14.1-27.6%, correspondingly, improved dry matter weight and N uptake after heading period by 4.3-29.1% and 11.8-55.1% （P 〈 0.05）, and heightened recovery efficiency and agronomic efficiency by 38.5-133.4% （P 〈 0.05） and 39.8-194.3% （P 〈 0.05）, respectively, as well as increased the average yield by 9.8% in 2004 and 2005. The results indicated that the accumulation rate of dry matter and N increased the rice yield and N use efficiency, because of improving rice population quality and increasing LAI after heading period.展开更多
Increasing nitrogen(N)rate could accelerate the decomposition of crop residues,and then improve crop yield by increasing N availability of soil and N uptake of crops.However,it is not clear whether N rate and plant de...Increasing nitrogen(N)rate could accelerate the decomposition of crop residues,and then improve crop yield by increasing N availability of soil and N uptake of crops.However,it is not clear whether N rate and plant density should be modified after a long period of cotton stubble return with high N rate.This study seeks to assess the effects of N rate and plant density on cotton yield,N use efficiency,leaf senescence,soil inorganic N,and apparent N balance in cotton stubble return fields in Liaocheng,China,in 2016 and 2017.Three plant densities 5.25(D_(5.25)),6.75(D_(6.75))and 8.25(D_(8.25))plants m^(-2) and five N rates 0(N_(0)),105(N_(105)),210(N_(210)),315(N315),and 420(N420)kg ha^(-1) were investigated.Compared to the combination used by local farmers(D_(5.25)N_(315)),a 33.3%N reduction and a 28.6%increase in plant density(D_(6.75)N_(210))can maintain high cotton yield,while a 66.7%N reduction at 6.75 plants m^(-2)(D_(6.75)N_(105))can only achieve high yield in the first year.Biological yield increased with the increase of N rate and plant density,and the highest yield was obtained under 420 kg N ha^(-1) at 8.25 plants m^(-2)(D_(8.25)N_(420))across the two years under investigation.Compared to D5.25N315,N agronomic efficiency(NAE)and N recovery efficiency(NRE)in D_(6.75)N_(210) increased by 30.2 and 54.1%,respectively,and NAE and NRE in D6.75N105 increased by 104.8 and 88.1%,respectively.Soil inorganic N decreased sharply under 105 kg N ha^(-1),but no change was found under 210 kg N ha^(-1) at 6.75 plants m^(-2).N deficit occurred under 105 kg N ha^(-1),but it did not occurr under 210 kg N ha^(-1) at 6.75 plants m^(-2).Net photosynthetic rate and N concentration of leaves under N rate ranging from 210 to 420 kg ha^(-1) were higher than those under N rate of 0 or 105 kg N ha^(-1) at all three densities.The findings suggest that D6.75N210 is a superior combination in cotton stubble retaining fields in the Yellow River Valley and other areas with similar ecologies.展开更多
In order to understand the yield performance and nitrogen （N） response of hybrid rice under different ecological conditions in southern China, field experiments were conducted in Huaiji County of Guangdong Province,...In order to understand the yield performance and nitrogen （N） response of hybrid rice under different ecological conditions in southern China, field experiments were conducted in Huaiji County of Guangdong Province, Binyang of Guangxi Zhuang Autonomous Region and Changsha City of Hunan Province, southern China in 2011 and 2012. Two hybrid （Liangyoupeijiu and Y-liangyou 1） and two inbred rice cultivars （Yuxiangyouzhan and Huanghuazhan） were grown under three N treatments （N1,225 kg ha-l; N2, 112.5-176 kg ha-l; N3, 0 kg ha-1） in each location. Results showed that grain yield was higher in Changsha than in Huaiji and Binyang for both hybrid and inbred cultivars. The higher grain yield in Changsha was attribut- ed to larger panicle size （spikelets per panicle） and higher biomass production. Consistently higher grain yield in hybrid than in inbred cultivars was observed in Changsha but not in Huaiji and Binyang. Higher grain weight and higher biomass production were responsible for the higher grain yield in hybrid than in inbred cultivars in Changsha. The better crop perfor- mance of rice （especially hybrid cultivars） in Changsha was associated with its temperature conditions and indigenous soil N. N2 had higher internal N use efficiency, recovery efficiency of applied N, agronomic N use efficiency, and partial factor productivity of applied N than N1 for both hybrid and inbred cultivars, while the difference in grain yield between N1 and N2 was relatively small. Our study suggests that whether hybrid rice can outyield inbred rice to some extent depends on the ecological conditions, and N use efficiency can be increased by using improved nitrogen management such as site-specific N management in both hybrid and inbred rice production.展开更多
China has the world’s highest nitrogen(N)application rate,and the lowest N use efficiency(NUE).With the crop yield increasing,serious N pollution is also caused.An in-situ field experiment(2011–2015)was conducted to...China has the world’s highest nitrogen(N)application rate,and the lowest N use efficiency(NUE).With the crop yield increasing,serious N pollution is also caused.An in-situ field experiment(2011–2015)was conducted to examine the effects of three N levels,0(i.e.,no fertilizer N addition to soil),120,and 180 kg N ha-1,using integrated rice management(IRM).We investigated rice yield,aboveground N uptake,and soil surface N budget in a hilly region of Southwest China.Compared to traditional rice management(TRM),IRM integrated raised beds,plastic mulch,furrow irrigation,and triangular transplanting,which significantly improved rice grain yield,straw biomass,aboveground N uptake,and NUE.Integrated rice management significantly improved 15N recovery efficiency(by 10%)and significantly reduced the ratio of potential15N loss(by 8%–12%).Among all treatments,the 120 kg N ha-1 level under IRM achieved the highest 15N recovery efficiency(32%)and 15N residual efficiency(29%),with the lowest 15N loss ratio(39%).After rice harvest,the residual N fertilizer did not achieve a full replenishment of soil N consumption,as the replenishing effect was insufficient(ranging from-31 to-49 kg N ha-1).Furthermore,soil surface N budget showed a surplus(69–146 kg N ha-1)under all treatments,and the N surplus was lower under IRM than TRM.These results indicate IRM as a reliable and stable method for high rice yield and high NUE,while exerting a minor risk of N loss.In the hilly area of Southwest China,the optimized N fertilizer application rate under IRM was found to be 100–150 kg N ha-1.展开更多
Periphytic biofilms are commonly presented at the water-soil interface in paddy fields. Different fertilization methods can affect the concentration and distribution of nutrients in paddy fields and thus affect the de...Periphytic biofilms are commonly presented at the water-soil interface in paddy fields. Different fertilization methods can affect the concentration and distribution of nutrients in paddy fields and thus affect the development of periphytic biofilms. In this study, the roles of periphytic biofilms in nitrogen(N) cycling in paddy systems and how they are affected by different fertilization methods were studied using microcosm experiments. Microcosms were prepared using soil samples from a paddy field and treated with surface and deep fertilization under light and dark conditions. Surface fertilization under light condition promoted the development of periphytic biofilms, while deep fertilization under dark condition inhibited their development. The development of periphytic biofilms increased the pH and dissolved oxygen levels in the overlying water. Surface fertilization resulted in high N concentrations in the overlying water and the topsoil layers, which enhanced NH3 volatilization and nitrification-denitrification but inhibited N fixation. The development of periphytic biofilms reduced NH3 volatilization loss but increased nitrification-denitrification loss and the overall N loss in the paddy system. The results from this work suggest that the presence of periphytic biofilms in paddy fields could increase N loss by 3.10%–7.11%. Deep fertilization is an effective method to retard the development of periphytic biofilms in the paddy system and can potentially increase the overall N use efficiency.展开更多
Annual ryegrass（Lolium multiflorum Lam.）, a non-leguminous winter cover crop, has been adopted to absorb soil native N to minimize N loss from an intensive double rice cropping system in southern China, but a little...Annual ryegrass（Lolium multiflorum Lam.）, a non-leguminous winter cover crop, has been adopted to absorb soil native N to minimize N loss from an intensive double rice cropping system in southern China, but a little is known about its effects on rice grain yield and rice N use efficiency. In this study, effects of ryegrass on double rice yield, N uptake and use efficiency were measured under different fertilizer N rates. A 3-year（2009–2011） field experiment arranged in a split-plot design was undertaken. Main plots were ryegrass（RG） as a winter cover crop and winter fallow（WF） without weed. Subplots were three N treatments for each rice season： 0（N_0）, 100（N_（100）） and 200 kg N ha–1（N_（200））. In the 3-year experiment, RG reduced grain yield and plant N uptake for early rice（0.4–1.7 t ha–1 for grain yield and 4.6–20.3 kg ha–1 for N uptake） and double rice（0.6–2.0 t ha–1 for grain yield and 6.3–27.0 kg ha–1 for N uptake） when compared with WF among different N rates. Yield and N uptake decrease due to RG was smaller in N_（100） and N_（200） plots than in N_0 plots. The reduction in early rice grain yield in RG plots was associated with decrease number of panicles. Agronomic N use efficiency and fertilizer N recovery efficiency were higher in RG plots than winter fallow for early rice and double rice among different N rates and experimental years. RG tended to have little effect on grain yield, N uptake, agronomic N use efficiency, and fertilizer N recovery efficiency in the late rice season. These results suggest that ryegrass may reduce grain yield while it improves rice N use efficiency in a double rice cropping system.展开更多
The application of nitrogen （N） fertilizers in agriculture has been increasing dramatically since 1970s. However, the over-fertilization causes could cause environmental problems, as well as low N use efficiency （...The application of nitrogen （N） fertilizers in agriculture has been increasing dramatically since 1970s. However, the over-fertilization causes could cause environmental problems, as well as low N use efficiency （NUE）. Promoting NUE in plants and minimizing the environmental impacts of N fertilizers had been the focus of the current research. We reviewed the importance of N, N metabolism and plant growth, plant N physiology and the molecular aspect of N metabolism in this paper. The future development of N use and NUE of plants was also discussed.展开更多
基金the National Natural Science Foundation of China(30210103901)Key Techno1ogies R&D Programme(2001BA507A-09-01-03)and 1ife science group of Yangzhou University.
文摘Using hybrid rice Shanyou63, the agronomic and economic characters of different nitrogen(N) managements were evaluated. The results showed that the grain yield of the control(N omission plots) ranged from 6.8 to 7.4 t ha-1, indicating the high indigenous N supplyof the soil. Compared with farmers fertilizer practice (FFP, 240 kg N ha-1), the modifiedFFP (70% N of FFP), real-time N management (RTNM, applying N based on values ofchlorophyll meter) and site-specific N management (SSNM, applying nitrogen based on thetiming, amount of N and values of chlorophyll meter) increased the grain yield by 9.2-10.3%, 3.3-7.0% and 8.9-9.3%, and agronomic N efficiency (the increase in grain yieldper unit N applied) by 110.5-135.6%, 204.3-297.0% and 200.9-276.4%, respectively. Theresults suggested that RTNM and SSNM have great potential for improving N use efficiencywithout sacrificing the grain yield. In addition, RTNM and SSNM also decreased chalkygrain percentage and chalkiness to improve grain appearance quality.
基金supported by the National Key Technology R&D Program (2011BAD12B03)
文摘Knowledge about crop growth processes in relation to N limitation is necessary to optimize N management in farming system. Plant-based diagnostic method, for instance nitrogen nutrition index （NNI） were used to determine the crop nitrogen status. This study determines the relationship of NNI with agronomic nitrogen use efficiency （AEN）, tuber yield, radiation use efficiency （RUE） and leaf parameters including leaf area index （LAI）, areal leaf N content （NJ and leaf N concentration （N0. Potatoes were grown in field at three N levels： no N （N 1）, 150 kg N ha^-1 （N2）, 300 kg N ha^-1 （N3）. N deficiency was quantified by NNI and RUE was generally calculated by estimating of the light absorbance on leaf area. NNI was used to evaluate the N effect on tuber yield, RUE, LAI, NAL, and NL. The results showed that NNI was negatively correlated with AEN, N deficiencies （NNI〈 1） which occurred for N 1 and N2 significantly reduced LAI, NL and tuber yield; whereas the N deficiencies had a relative small effect on NAL and RUE. To remove any effect other than N on these parameters, the actual ratio to maximum values were calculated for each developmental linear relationships were obtained between NNI and tuber RUE to NNI. stage of potatoes. When the NNI ranged from 0.4 to 1, positive yield, LAI, NL, while a nonlinear regression fitted the response of
基金supported by the Youth Scientific Research Foundation of Shandong Academy of Agricultural Sciences, China(2014QNM27)the Applying Basic Research Project of Qingdao,Shandong Province,China(14-2-4-90-jch)+3 种基金the Modern Agricultural Industry Technology System,China (SDAIT-05-021-04)the National Key Technology R&D Program of China(2014BAD11B04)the Key Innovation of Science and Technology Project of Shandong Academy of Agricultural Sciences,China(2014CXZ06-22014CXZ11-2)
文摘Rational application of different forms of nitrogen（N） fertilizer for peanut（Arachis hypogaea L.） requires tracking the N supplied sources which are commonly not available in the differences among the three sources：root nodule,soil and fertilizer.In this study,two kinds of peanut plants（nodulated variety（Huayu 22） and non-nodulated variety（NN-1）） were choosed and four kinds of N fertilizers：urea-N（CONH_2-N）,ammonium-N（NH_4~＋-N）,nitrate-N（NO_3^--N） and NH_4~＋ ＋NO_3^--N labeled by^（15）N isotope were applied in the field barrel experiment in Chengyang Experimental Station,Shandong Province,China,to determine the N supplied sources and N use efficiency over peanut growing stages.The results showed that intensities and amounts of N supply from the three sources were all higher at middle growing stages（pegging phase and podding phase）.The accumulated amounts of N supply from root nodule,soil and fertilizer over the growing stages were 8.3,5.3 and 3.8g m^（-2） in CONH_2-N treatment,which are all significantly higher than in the other three treatments.At seedling phase,soil supplied the most N for peanut growth,then root nodule controlled the N supply at pegging phase and podding phase,but soil mainly provided N again at the last stage（pod filling phase）.For the whole growing stages,root nodule supplied the most N（47.8 and 43.0%） in CONH_2-N and NH_4~＋-N treatments,whereas soil supplied the most N（41.7 and 40.9%） in NH_4~＋ ＋NO_3^--N and NO_3^--N treatments.The N use efficiency was higher at pegging phase and podding phase,while accumulated N use efficiency over the growing stages was higher in CONH_2-N treatment（42.2%） than in other three treatments（30.4%in NH_4~＋-N treatment,29.4%in NO_3^--N treatment,29.4%in NH_4~＋ ＋NO_3^--N treatment）.In peanut growing field,application of CONH_2-N is a better way to increase the supply of N from root nodule and improve the N use efficiency.
基金Supported by National Key R&D Program(2016YFD030010)National Innovation Experiment Program for University students(20150083,2016099)
文摘In order to investigate effects of topdressing on grain yield and N use efficiency of mechanically-transplanted hybrid rice, this experiment was conducted with 2-line hybrid rice cultivars, Quaniiangyou 1 and Quanliangyou 681 with 3 application levels of N fertilizer, No, N1, N2, respectively. The results showed that there were no significant differences in grain yields of the 2 varieties between treatments N1 and N2. It was indicated that N is not the factor which could limit grain yield within limited application levels of N fertilizer. High N fertilizer treatment could contribute to the formation of effective panicles and spikelets per panicle, but it could also lead to the decline in grain filling rate. It was suggested that lowering the amount of Nfertilizer could facilitate improvement of N-use efficiency.
基金supported by the National Natural Science Foundation of China (32301930, 32071943, 32272198, and 32372214)the Major Program of the Ministry of Agriculture and Rural Affairs of China (FSNK202218080316)+3 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions, China (PAPD-2020-01)the Jiangsu Funding Program for Excellent Postdoctoral Talent, China (2022ZB618)the Government Funding to the Chinese University of Hong Kong State Key Laboratory of Agrobiotechnology via Innovation and Technology Commission, China (2022/23–2023/24)the National Key Research and Development Program of China (2022YFD2300304)。
文摘Aligning leaf nitrogen(N) distribution to match the light gradient is crucial for maximizing canopy dry matter production(DMP) and improving N utilization efficiency. However, the relationship between the gradient of root-derived cytokinins and N distribution in rice leaves and its impact on DMP and the underlying mechanisms remains poorly understood. A two-year field experiment was conducted using two japonica N-efficient varieties(NEVs) and two japonica N-inefficient varieties(NIVs) under four different N rates(0, 90, 180, and 360 kg N ha^(-1)). These selected varieties exhibited similar values in the coefficient of light extinction(K_(L)). Results showed that at lower N rates(0–180 kg N ha^(-1)), the NEVs exhibited greater dry matter weight at maturity, higher grain yield, and improved internal N use efficiency(IE_(N)) compared to the NIVs, despite possessing comparable total N uptake. Compared with the NIVs, the NEVs exhibited a more pronounced nitrogen distribution gradient in leaves, as indicated by the coefficient of nitrogen extinction(K_(N)) values during the middle and early grain-filling stages. This enhanced gradient led to improved coordination between light and nitrogen, resulting in greater photosynthetic production, particularly at lower N rates. Furthermore, the NEVs demonstrated a larger gradient of zeatin(Z)+zeatin riboside(ZR) in leaves(i.e., higher ratios of Z+ZR levels between upper and lower leaves), enhanced expression levels of genes related to N export in lower leaves and Z+ZR loading in the root, respectively, elevated enzymes activities related to N assimilation in upper leaves, in relative to the NIVs. Correlation and random forest analyses demonstrated a strong positive correlation between the Z+ZR gradient, K_(N), and DMP, and the gradient facilitated the export of N from lower leaves and its assimilation in upper leaves, contributing significantly to both K_(N) and DMP. This process was closely linked to root activity, including root oxidation activity, root Z+ZR content, and Z+ZR loading capacity, as confirmed by applying an inhibitor or a promoter of cytokinins biosynthesis to roots. Interestingly, at the N rate of 360 kg N ha^(-1), both NEVs and NIVs showed indistinguishable plant traits, achieving a super high-yielding level(over 10.5 t ha^(-1)) but with remarkably low IE_(N). The results suggest that increasing the Z+ZR gradient can improve K_(N) and DMP, where it needs to maintain higher root activity, thus leading to high yield and high IE_(N). Further research is needed to explore and develop cultivation practices with reduced N to unlock the super-high-yielding potential of the NEVs.
基金funded by grants from the National Natural Science Foundation of China(32301947,32272220 and 32172120)the China Postdoctoral Science Foundation(2023M730909).
文摘Nitrogen(N)serves as an essential nutrient for yield formation across diverse crop types.However,agricultural production encounters numerous challenges,notably high N fertilizer rates coupled with low N use efficiency and serious environmental pollution.Deep placement of nitrogen fertilizer(DPNF)is an agronomic measure that shows promise in addressing these issues.This review aims to offer a comprehensive understanding of DPNF,beginning with a succinct overview of its development and methodologies for implementation.Subsequently,the optimal fertilization depth and influencing factors for different crops are analyzed and discussed.Additionally,it investigates the regulation and mechanism underlying the DPNF on crop development,yield,N use efficiency and greenhouse gas emissions.Finally,the review delineates the limitations and challenges of this technology and provides suggestions for its improvement and application.This review provides valuable insight and reference for the promotion and adoption of DPNF in agricultural practice.
基金Crop Harvest Technology and Engineering in the Twelfth Five-year Plan (2011BAD16B15-2)Special Foundation of National Modern Maize Industrial Technology System(nycytx-02-17)Cooperation Project of China-International Plant Nutrition Research Institute (NMBF-HenanAU-2009)~~
文摘[Objective] The aim was to explore effects of application postponing of N fertilizer and the mechanism of yield increase in order to provide references for N fertilizer application in a rational way. [Method] In a super-high yielded region of summer maize, field experiment was conducted to research effects of N fertilizer postponing on key enzymes of N metabolism, yield of maize and N fertilizer use. [Result] After application of N fertilizer was postponed, NR, SPS and GS activities of ear-leaf of summer maize increased by 11.99%-34.87%, 8.25%-10.64% and 10.00%- 16.81% on the 28^th d of silking; content of soluble sugar in leaves enhanced signifi- cantly and accumulated nitrogen increased by 5.00%-9.74% in mature stage. The postponing fertilization of ＂30% of fertilizer in seedling stage＋30% of fertilizer in flare- opening stage＋40% of fertilizer in silking stage meets N demands of summer maize in late growth period. Compared with conventional fertilization, the maize yield, agro- nomic efficiency and use of N fertilizer all improved by 5.05%, 1.75 kg/kg and 6.87%, respectively, after application postponed. [Conclusion] Application postponing of N fertilizer maintains activity of NR, GS and SPS higher and coordinates metabolism of C and N in late growth period, to further improve yield of maize.
基金Supported by the National Natural Science Foundation of China-Japan Science and Technology Agency (NSFC-JST)Major International Joint Research Project (No. 30821140542)+1 种基金the National Basic Research Program (973 Program) of China (No. 2007CB109303)the Major Science and Technology Program for Water Pollution Control and Treatment of China (No. 2008ZX07101-005)
文摘High rates of fertilizer nitrogen (N) are applied in greenhouse vegetable fields in southeastern China to maximize production;however,the N budgets of such intensive vegetable production remain to be explored.The goal of this study was to determine the annual N balance and loss in a greenhouse vegetable system of annual rotation of tomato,cucumber,and celery at five N (urea) application rates (0,348,522,696,and 870 kg N ha-1 year-1).Total N input to the 0-50 cm soil layer ranged from 531 to 1 053 kg ha-1,and N fertilizer was the main N source,accounting for 66%-83% of the total annual N input.In comparison,irrigation water,wet deposition,and seeds in total accounted for less than 1% of the total N input.The fertilizer N use efficiency was only 18% under the conventional application rate of 870 kg N ha-1 and decreased as the application rate increased from 522 to 870 kg N ha-1.Apparent N losses were 196-201 kg N ha-1,of which 71%-86% was lost by leaching at the application rates of 522-870 kg N ha-1.Thus,leaching was the primary N loss pathway at high N application rates and the amount of N leached was proportional to the N applied during the cucumber season.Moreover,dissolved organic N accounted for 10% of the leached N,whereas NH3 volatilization only contributed 0.1%-0.6% of the apparent N losses under the five N application rates in this greenhouse vegetable system.
基金Financial supports by the National Natural Science Foun-dation of China (30070431)the Key Technologies R&D Program of China during the 9th Five-Year Plan period(95-Agric-18-04)+1 种基金the Doctoral Fund of Ministry of Edu-cation of China (200805041061)the Earmarked Fund for Modern Agro-Industry Technology Research System, China
文摘The objective is to study whether the accumulation and utilization of plant N are controlled by Mo status in winter wheat cultivars. Mo-efficient cultivar 97003 （eft） and Mo-inefficient cultivar 97014 （ineff） were grown in severely Mo-deficient acidic soil （Tamm-reagent-extractable Mo 0.112 mg kg^-1） with （＋Mo） and without （-Mo） the application of 0.13 mg kg^-1 Mo. The accumulation and use efficiency of plant total N were significantly higher in ＋Mo than that in -Mo and in eft than that in ineff under Mo deficiency. N use efficiency was remarkably higher in maturity but it was forwarded to jointing stage after Mo supply, thus indicating that Mo supply promoted the N use efficiency besides N uptake and eff was efficient in N uptake and utilization. The overall activity of nitrate reductase （NR, EC 1.6.6.1） was significantly higher in ＋Mo than in -Mo and ratio of ＋Mo/-Mo was even to 14.8 at filleting stage for ineff. Activity of glutamine synthetase （GS, EC 6.3.1.2） was significantly lower in ＋Mo than in -Mo. Concentration of nitrate and glutamate were also significantly lower in ＋Mo than in -Mo, thus provided evidences for enhancing N use efficiency by Mo supply. Activities of NR and GS were significantly higher and concentrations of nitrate and glutamate were significantly lower in eff than ineff under Mo deficiency, thus indicated eff was more efficient in N reduction and utilization. It is therefore concluded that Mo could promote N accumulation and utilization in winter wheat which was directly related to NR and feedback regulated by GS. Higher Mo status also results in higher accumulation and utilization of plant N in eft.
基金supported by the National Natural Science Foundation of China (Nos. 31201154 and 31571596)the Open Project Program of Jiangsu Province Key Laboratory of Crop Physiology,China (No. K12008)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Due to the relatively late start of organic rice(Oryza sativa L.) research in China,there is a still lack of systematic research on rice varieties,organic fertilizer management practices,and especially the mechanisms of nitrogen(N) uptake and utilization.Three rice varieties,Nanjing 5055,Nanjing 9108,and Nanjing 46,were grown under organic farming(OF) at three organic fertilizer levels(103.2,160.8,and 218.4 kg N ha^(-1)) and conventional farming(CF) with regular chemical fertilizers.Rice grain yields,yield components,and quality,dry matter accumulation,and plant N were measured at different growth stages during the 2012 and 2013 growing seasons.Compared with CF,OF had a significantly reduced yield.Nanjing 9108 showed significant reductions in number of panicles per unit area and percentage of filled grains,and had the lowest yield.The effects of fertilizer type and application rate on dry matter accumulation during the main growth periods were significant for all varieties.The N content and uptake in organically grown rice were lower compared with those of rice under CF.The N recovery efficiency and N agronomic efficiency were significantly lower,whereas N physiological efficiency and N partial factor productivity were greater under OF than under CF.Under OF,the processing quality showed a slight but insignificant decline,protein content and gel consistency increased,and amylose content decreased compared with those under CF.Correlation analysis showed that under OF,grain yield was significantly correlated with N uptake.The medium organic fertilizer level(160.8 kg N ha^(-1)) was found to be the optimum fertilizer treatment,and Nanjing 46 appeared to be the best variety for organic rice cultivation.To increase rice grain yields and reduce the potential risk of non-point source pollution in organic agriculture,further research is needed to improve the N use efficiency in organic rice cultivation.
文摘Fertilizers contribute greatly to high yields but also result in environmental non-point contamination, including the emission of greenhouse gas(N 2O) and eutrophication of water bodies. How to solve this problem has become a serious challenge, especially for China as its high ecological pressure. Controlled-release fertilizer(CRF) has been developed to minimize the contamination while keeping high yield and has become a green fertilizer for agriculture. Several CRFs made with special coating technology were used for testing the fertilizer effects in yield and environment through pot experiment and field trial. The result indicated that the CRFs had higher N use efficiency, thus reducing N loss through leaching and volatilization while keeping higher yields. Comparing with imported standard CRFs, the test on CRFs showed similar fertilizer effect but with much lower cost. CRFs application is becoming a new approach for minimizing non-point contamination in agriculture.
基金the National Natural Science Foundation of China(3117 1497)the National Basic Research Program of China(973 Program,2011CB100105)+1 种基金the National Food Science and Technology of High Yield Program of China(2011BAD16B09)the Special Fund for Agro-scientific Research in the Public Interest of China(201203096)
文摘Planting at an optimum density and supplying adequate nitrogen（N） to achieve higher yields is a common practice in crop production, especially for maize（Zea mays L.）; however, excessive N fertilizer supply in maize production results in reduced N use efficiency（NUE） and severe negative impacts on the environment. This research was conducted to determine the effects of increased plant density and reduced N rate on grain yield, total N uptake, NUE, leaf area index（LAI）, intercepted photosynthetically active radiation（IPAR）, and resource use efficiency in maize. Field experiments were conducted using a popular maize hybrid Zhengdan 958（ZD958） under different combinations of plant densities and N rates to determine an effective approach for maize production with high yield and high resource use efficiency. Increasing plant density was clearly able to promote N absorption and LAI during the entire growth stage, which allowed high total N uptake and interception of radiation to achieve high dry matter accumulation（DMA）, grain yield, NUE, and radiation use efficiency（RUE）. However, with an increase in plant density, the demand of N increased along with grain yield. Increasing N rate can significantly increase the DMA, grain yield, LAI, IPAR, and RUE. However, this increase was non-linear and due to the input of too much N fertilizers, the efficiency of N use at NCK（320 kg ha^（–1）） was low. An appropriate reduction in N rate can therefore lead to higher NUE despite a slight loss in grain production. Taking into account both the need for high grain yield and resource use efficiency, a 30% reduction in N supply, and an increase in plant density of 3 plants m^（–2）, compared to LD（5.25 plants m^（–2））, would lead to an optimal balance between yield and resource use efficiency.
基金the National Natural Science Foundation of China (No.21107139)the Ministry of Agriculture Public Benefit Research Foundation of China (No.201103007)+1 种基金the Special Fund of Research Institute Technology Development of China (No.2012EG134235)the National Basic Research Program (973 program) of China (No.2007CB109308)
文摘As a result of intensive greenhouse vegetable production in northern China, the potential risk of nitrogen （N） fertilizer over-applied is increasingly apparent and is threatening ecosystem and the sustainability of food production. An experiment was carried out in Shouguang, Shangdong Province, China to evaluate agronomic benefit and soil quality under different N applications, including the conventional chemical N rate （1000 kg N ha^（-1） season^（-1）, N1）, 70% of N1 （N2）, 70% of N1 ＋ maize straw （N3）, 50% of N1 ＋ maize straw ＋ drip irrigation （N4）, and 0% of N1 （NO）, during two successive growing seasons of autumn-winter （AW） and winter-spring （WS）. The maximum yields for N4 were 1.1 and 1.0 times greater than those for N1 in the AW and WS seasons, respectively. N agronomic efficiency （AEN） and apparent N recovery efficiency （REN） were greatest with the N4. A significant relationship was found between soil NO3-N content and electrical conductivity （EC） （R^2 = 0.61 in the AW season and R^2= 0.29 in the WS season）. Reducing N fertilizer decreased soil NO3-N accumulation （20.9%-37.8% reduction in the AW season and 11.7%-20.1% reduction in the WS season） relative to the accumulation observed for N1 within the 0-100 cm soil layer. Soil urease and invertase activities were not significantly different among N treatments. The N4 treatment would be practical for reducing excess N input and maintaining the sustainability of greenhouse-based intensive vegetable systems in Shouguang.
文摘The effects of yield increase and mechanism of site-specific nitrogen management （SSNM） in five rice varieties from cold areas of northeastern China were studied. Plot experiment for critical SPAD value and experiments of two fertilization methods, SSNM and farmer＇s fertilization practice （FFP） were conducted to study their effects on the quality and dry matter accumulation of rice population, as well as N uptake. Compared with FFP, SSNM significantly decreased the average N rate by 33.8%, significantly increased average ear-bearing tiller rate and LAI for grain-filling stage by 12.3% and 14.1-27.6%, correspondingly, improved dry matter weight and N uptake after heading period by 4.3-29.1% and 11.8-55.1% （P 〈 0.05）, and heightened recovery efficiency and agronomic efficiency by 38.5-133.4% （P 〈 0.05） and 39.8-194.3% （P 〈 0.05）, respectively, as well as increased the average yield by 9.8% in 2004 and 2005. The results indicated that the accumulation rate of dry matter and N increased the rice yield and N use efficiency, because of improving rice population quality and increasing LAI after heading period.
基金The study was supported by the National Natural Science Foundation of China(31601253)the Natural Science Foundation of Shandong Province,China(ZR2016CQ20)+1 种基金the China Postdoctoral Science Foundation(2017M610438)the Modern Agro-industry Technology Research System of Shandong Province,China(SDAIT-03-03/05).
文摘Increasing nitrogen(N)rate could accelerate the decomposition of crop residues,and then improve crop yield by increasing N availability of soil and N uptake of crops.However,it is not clear whether N rate and plant density should be modified after a long period of cotton stubble return with high N rate.This study seeks to assess the effects of N rate and plant density on cotton yield,N use efficiency,leaf senescence,soil inorganic N,and apparent N balance in cotton stubble return fields in Liaocheng,China,in 2016 and 2017.Three plant densities 5.25(D_(5.25)),6.75(D_(6.75))and 8.25(D_(8.25))plants m^(-2) and five N rates 0(N_(0)),105(N_(105)),210(N_(210)),315(N315),and 420(N420)kg ha^(-1) were investigated.Compared to the combination used by local farmers(D_(5.25)N_(315)),a 33.3%N reduction and a 28.6%increase in plant density(D_(6.75)N_(210))can maintain high cotton yield,while a 66.7%N reduction at 6.75 plants m^(-2)(D_(6.75)N_(105))can only achieve high yield in the first year.Biological yield increased with the increase of N rate and plant density,and the highest yield was obtained under 420 kg N ha^(-1) at 8.25 plants m^(-2)(D_(8.25)N_(420))across the two years under investigation.Compared to D5.25N315,N agronomic efficiency(NAE)and N recovery efficiency(NRE)in D_(6.75)N_(210) increased by 30.2 and 54.1%,respectively,and NAE and NRE in D6.75N105 increased by 104.8 and 88.1%,respectively.Soil inorganic N decreased sharply under 105 kg N ha^(-1),but no change was found under 210 kg N ha^(-1) at 6.75 plants m^(-2).N deficit occurred under 105 kg N ha^(-1),but it did not occurr under 210 kg N ha^(-1) at 6.75 plants m^(-2).Net photosynthetic rate and N concentration of leaves under N rate ranging from 210 to 420 kg ha^(-1) were higher than those under N rate of 0 or 105 kg N ha^(-1) at all three densities.The findings suggest that D6.75N210 is a superior combination in cotton stubble retaining fields in the Yellow River Valley and other areas with similar ecologies.
基金supported by the Earmarked Fund for Modern Agro-Industry Technology of China (CARS-01-34)
文摘In order to understand the yield performance and nitrogen （N） response of hybrid rice under different ecological conditions in southern China, field experiments were conducted in Huaiji County of Guangdong Province, Binyang of Guangxi Zhuang Autonomous Region and Changsha City of Hunan Province, southern China in 2011 and 2012. Two hybrid （Liangyoupeijiu and Y-liangyou 1） and two inbred rice cultivars （Yuxiangyouzhan and Huanghuazhan） were grown under three N treatments （N1,225 kg ha-l; N2, 112.5-176 kg ha-l; N3, 0 kg ha-1） in each location. Results showed that grain yield was higher in Changsha than in Huaiji and Binyang for both hybrid and inbred cultivars. The higher grain yield in Changsha was attribut- ed to larger panicle size （spikelets per panicle） and higher biomass production. Consistently higher grain yield in hybrid than in inbred cultivars was observed in Changsha but not in Huaiji and Binyang. Higher grain weight and higher biomass production were responsible for the higher grain yield in hybrid than in inbred cultivars in Changsha. The better crop perfor- mance of rice （especially hybrid cultivars） in Changsha was associated with its temperature conditions and indigenous soil N. N2 had higher internal N use efficiency, recovery efficiency of applied N, agronomic N use efficiency, and partial factor productivity of applied N than N1 for both hybrid and inbred cultivars, while the difference in grain yield between N1 and N2 was relatively small. Our study suggests that whether hybrid rice can outyield inbred rice to some extent depends on the ecological conditions, and N use efficiency can be increased by using improved nitrogen management such as site-specific N management in both hybrid and inbred rice production.
基金supported by the National Key Research and Development Program of China(Nos.2017YFD0301705 and 2018YFD0301203)the Innovation Ability Enhancement Nonprofit Research Deepening Project of Sichuan Province Financial Department,China(No.016GYSH-021)+1 种基金the Youth Foundation of Sichuan Academy of Agricultural Sciences,China(No.2015QNJJ-016)the Open Project of State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences(No.Y20160039)
文摘China has the world’s highest nitrogen(N)application rate,and the lowest N use efficiency(NUE).With the crop yield increasing,serious N pollution is also caused.An in-situ field experiment(2011–2015)was conducted to examine the effects of three N levels,0(i.e.,no fertilizer N addition to soil),120,and 180 kg N ha-1,using integrated rice management(IRM).We investigated rice yield,aboveground N uptake,and soil surface N budget in a hilly region of Southwest China.Compared to traditional rice management(TRM),IRM integrated raised beds,plastic mulch,furrow irrigation,and triangular transplanting,which significantly improved rice grain yield,straw biomass,aboveground N uptake,and NUE.Integrated rice management significantly improved 15N recovery efficiency(by 10%)and significantly reduced the ratio of potential15N loss(by 8%–12%).Among all treatments,the 120 kg N ha-1 level under IRM achieved the highest 15N recovery efficiency(32%)and 15N residual efficiency(29%),with the lowest 15N loss ratio(39%).After rice harvest,the residual N fertilizer did not achieve a full replenishment of soil N consumption,as the replenishing effect was insufficient(ranging from-31 to-49 kg N ha-1).Furthermore,soil surface N budget showed a surplus(69–146 kg N ha-1)under all treatments,and the N surplus was lower under IRM than TRM.These results indicate IRM as a reliable and stable method for high rice yield and high NUE,while exerting a minor risk of N loss.In the hilly area of Southwest China,the optimized N fertilizer application rate under IRM was found to be 100–150 kg N ha-1.
基金the support from the State Key Development Program for Basic Research of China (No. 2015CB158200)the State Key Laboratory of Freshwater Ecology and Biotechnology of China (No. 2019FBZ03)。
文摘Periphytic biofilms are commonly presented at the water-soil interface in paddy fields. Different fertilization methods can affect the concentration and distribution of nutrients in paddy fields and thus affect the development of periphytic biofilms. In this study, the roles of periphytic biofilms in nitrogen(N) cycling in paddy systems and how they are affected by different fertilization methods were studied using microcosm experiments. Microcosms were prepared using soil samples from a paddy field and treated with surface and deep fertilization under light and dark conditions. Surface fertilization under light condition promoted the development of periphytic biofilms, while deep fertilization under dark condition inhibited their development. The development of periphytic biofilms increased the pH and dissolved oxygen levels in the overlying water. Surface fertilization resulted in high N concentrations in the overlying water and the topsoil layers, which enhanced NH3 volatilization and nitrification-denitrification but inhibited N fixation. The development of periphytic biofilms reduced NH3 volatilization loss but increased nitrification-denitrification loss and the overall N loss in the paddy system. The results from this work suggest that the presence of periphytic biofilms in paddy fields could increase N loss by 3.10%–7.11%. Deep fertilization is an effective method to retard the development of periphytic biofilms in the paddy system and can potentially increase the overall N use efficiency.
基金supported by the National Natural Science Foundation of China(31501274,31171509,30671222,31270488)the Special Fund for Agro-scientific Research in the Public Interest,China(201103001)the National Key Technologies R&D Program of China during the 12th Five-Year Plan period(2011BAD16B15)
文摘Annual ryegrass（Lolium multiflorum Lam.）, a non-leguminous winter cover crop, has been adopted to absorb soil native N to minimize N loss from an intensive double rice cropping system in southern China, but a little is known about its effects on rice grain yield and rice N use efficiency. In this study, effects of ryegrass on double rice yield, N uptake and use efficiency were measured under different fertilizer N rates. A 3-year（2009–2011） field experiment arranged in a split-plot design was undertaken. Main plots were ryegrass（RG） as a winter cover crop and winter fallow（WF） without weed. Subplots were three N treatments for each rice season： 0（N_0）, 100（N_（100）） and 200 kg N ha–1（N_（200））. In the 3-year experiment, RG reduced grain yield and plant N uptake for early rice（0.4–1.7 t ha–1 for grain yield and 4.6–20.3 kg ha–1 for N uptake） and double rice（0.6–2.0 t ha–1 for grain yield and 6.3–27.0 kg ha–1 for N uptake） when compared with WF among different N rates. Yield and N uptake decrease due to RG was smaller in N_（100） and N_（200） plots than in N_0 plots. The reduction in early rice grain yield in RG plots was associated with decrease number of panicles. Agronomic N use efficiency and fertilizer N recovery efficiency were higher in RG plots than winter fallow for early rice and double rice among different N rates and experimental years. RG tended to have little effect on grain yield, N uptake, agronomic N use efficiency, and fertilizer N recovery efficiency in the late rice season. These results suggest that ryegrass may reduce grain yield while it improves rice N use efficiency in a double rice cropping system.
基金Supported by the National Natural Science Foundation of China(3127219131372091)the Natural Science Foundation of Heilongjiang Province(C200619)
文摘The application of nitrogen （N） fertilizers in agriculture has been increasing dramatically since 1970s. However, the over-fertilization causes could cause environmental problems, as well as low N use efficiency （NUE）. Promoting NUE in plants and minimizing the environmental impacts of N fertilizers had been the focus of the current research. We reviewed the importance of N, N metabolism and plant growth, plant N physiology and the molecular aspect of N metabolism in this paper. The future development of N use and NUE of plants was also discussed.
