Straw return is an important management tool for tackling and promoting soil nutrient conservation and improving crop yield in Huang-Huai-Hai Plain, China. Although the incorporation of maize straw with deep plowing a...Straw return is an important management tool for tackling and promoting soil nutrient conservation and improving crop yield in Huang-Huai-Hai Plain, China. Although the incorporation of maize straw with deep plowing and rotary tillage practices are widespread in the region, only few studies have focused on rotation tillage. To determine the effects of maize straw return on the nitrogen （N） efficiency and grain yield of winter wheat （Triticum aestivum L.）, we conducted experiments in this region for 3 years. Five treatments were tested： （i） rotary tillage without straw return （RT）; （ii） deep plowing tillage without straw return （DT）; （iii） rotary tillage with total straw return （RS）; （iv） deep plowing tillage with total straw return （DS）; （v） rotary tillage of 2 years and deep plowing tillage in the 3rd year with total straw return （TS）. Treatments with straw return increased kernels no. ear-1, thousand-kernel weight （TKW）, grain yields, ratio of dry matter accumulation post-anthesis, and nitrogen （N） efficiency whereas reduced the ears no. ha-1 in the 2011-2012 and 2012-2013 growing seasons. Compared with the rotary tillage, deep plowing tillage significantly increased the grain yield, yield components, total dry matter accumulation, and N efficiency in 2013-2014. RS had significantly higher straw N distribution, soil inorganic nitrogen content, and soil enzymes activities in the 0-10 cm soil layer compared with the DS and TS. However, significantly lower values were ob- served in the 10-20 and 20-30 cm soil layers. TS obtained approximately equal grain yield as DS, and it also reduced the resource costs. Therefore, we conclude that TS is the most economical method for increasing grain yield and N efficiency of winter wheat in Huang-Huai-Hai Plain.展开更多
Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N ferti...Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N fertilizer treatments, applied in triplicate, were 0 （control）, 100, 200, 300, or 350 kg N ha^-1. After urea was applied to the surface water, a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field. Total N losses through ammonia volatilization generally increased with the N application rate, and the two higher N application rates （300 and 350 kg N ha^-1） showed a higher ratio of N lost through ammonia volatilization to applied N. Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N. Increasing the application rate generally decreased the ratio of N in the seed to N in the plant. For all N treatments, the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%. Surplus N with the highest N rate resulted in lodging of rice plants, a decreased rate of nitrogen fertilizer utilization, and reduced rice yields. Calculated from this experiment, the most economical N fertilizer application rate was 227 kg ha^-1 for the type of paddy soil in the Taihu Lake region. However, recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.展开更多
Field trials on a silt-loamy paddy soil derived from shallow-sea deposit in direct seeding rice fields were conducted in Zhejiang, China, in 1996 to compare N efficiency of controlled release fertilizers (LP fertilize...Field trials on a silt-loamy paddy soil derived from shallow-sea deposit in direct seeding rice fields were conducted in Zhejiang, China, in 1996 to compare N efficiency of controlled release fertilizers (LP fertilizers) with the conventional urea. Six treatments including CK (no N fertilizer), conventional urea and different types of LP fertilizers at different rates were designed for two succeeding crops of early and late rice. A blend of different types of LP fertilizers as a single preplant "co-situs" application released N in a rate and amount synchronizing with uptake pattern of direct seeding rice. A single preplant application of the LP fertilizers could meet the N requirement of rice for the whole growth period without need of topdressing. Using LP fertilizer blends, equivalent grain yields could be maintained even if the N fertilization rates were reduced by 25%～50% compared with the conventional urea. Agronomic efficiency of the LP fertilizers was 13.6%～ 86.4% higher than that of the conventional urea in early rice and 100%～164.1% in late rice, depending on the amounts of the LP fertilizers applied. N fertilizer recovery rate increased from 27.4% for the conventional application of urea to 41.7%～54.l% for the single preplant "co-situs" application of the LP fertilizers. Use of the LP fertilizers was promising if the increase in production costs due to the high LP fertilizer prices could be compensated by increase in yield and N efficiency, reduction in labor costs and improvement in environment.展开更多
We report on fabrication and photovoltaic characteristics of InxGa1-xN/GaN multiple quantum well solar cells with different indium compositions and barrier thicknesses. The as-grown samples are characterized by high- ...We report on fabrication and photovoltaic characteristics of InxGa1-xN/GaN multiple quantum well solar cells with different indium compositions and barrier thicknesses. The as-grown samples are characterized by high- resolution x-ray diffraction and reciprocal space mapping. The results show that the sample with a thick barrier thickness （lO.Onm） and high indium composition （0.23） has better crystalline quality. In addition, the dark current density-voltage （J-V） measurement of this device shows a significant decrease of leakage current, which leads to high open-circuit voltage Vow. Through the J-V characteristics under an Air Mass 1.5 Global （AM 1.5 G） illumination, this device exhibits a Voc of 1.89 V, a short-circuit current density Ysc of 3.92mA/cm2 and a fill factor of 50.96%. As a result, the conversion efficiency （77） is enhanced to be 3.77% in comparison with other devices.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
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
Overestimation of nitrogen（N） uptake requirement is one of the driving forces of the overuse of N fertilization and the low efficiency of N use in China. In this study, we collected data from 1 844 site-years of ric...Overestimation of nitrogen（N） uptake requirement is one of the driving forces of the overuse of N fertilization and the low efficiency of N use in China. In this study, we collected data from 1 844 site-years of rice（Oryza sativa L.） under various rotation cropping systems across the Yangtze River Valley. Selected treatments included without（N0 treatment） and with N application（N treatment） which were recommended by local technicians, with a wide grain range of 1.5–11.9 t ha–1. Across the 1 844 site-years, over 96% of the sites showed yield increase（relative yield〉105%） with N fertilization, and the increase rates decreased from 78.9 to 16.2% within the lowest range 〈4.0 to the highest 〉6.5 t ha–1. To produce one ton of grain, the rice absorbed approximately 17.8 kg N in the N0 treatment and 20.4 kg N in the N treatment. The value of partial factor productivity by N（PFP N） reached a range of 35.2–51.4 kg grain kg–1 with N application under the current recommended N rate. Averaged recovery rate of N（RE N） was above 36.0% in yields below 6.0 t ha–1 and lower than 31.7% in those above 6.0 t ha–1. Soil properties only affected yield increments within low rice yield levels（〈5.5 t ha–1）. There is a poor relationship between N application rates and indigenous nitrogen supply（INS）. From these observations and considering the local INS, we concluded there was a great potential for improvement in regional grain yield and N efficiency.展开更多
There is a need for rice cultivars with high yields and nitrogen(N) use efficiency(NUE), but with low cadmium(Cd) accumulation in Cd-contaminated paddy soils.To determine the relative effects of rice genotype, soil ty...There is a need for rice cultivars with high yields and nitrogen(N) use efficiency(NUE), but with low cadmium(Cd) accumulation in Cd-contaminated paddy soils.To determine the relative effects of rice genotype, soil type, and Cd addition on rice grain yield and NUE, a pot experiment consisting of nine rice cultivars was conducted in two types of paddy soils, red soil(RS) and yellow soil(YS),without or with Cd spiked at 0.6 mg kg^(-1).The N supply was from both soil organic N pools and N fertilizers; thus, NUE was defined as the grain yield per unit of total crop-available N in the soil.Cd addition decreased grain yield and NUE in most rice cultivars,which was mainly related to reduced N uptake efficiency(NpUE, defined as the percentage of N taken up by the crop per unit of soil available N).However, Cd addition enhanced N assimilation efficiency(NtUE, defined as the grain yield per unit of N taken up by the crop) by 21.9% on average in all rice cultivars.The NpUE was mainly affected by soil type, whereas NtUE was affected by rice cultivar.Hybrid cultivars had higher NUEs than the japonica and indica cultivars because of their greater biomass and higher tolerance to Cd contamination.Reduction of NUE after Cd addition was stronger in RS than in YS, which was related to the lower absorption capacity for Cd in RS.Canonical correspondence analysis-based variation partitioning showed that cultivar type had the largest effect(34.4%) on NUE, followed by Cd addition(15.2%) and soil type(10.0%).展开更多
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 nitrogen(N) application can greatly increase rice(Oryza sativa L.) yield. However, excessive N input can lead not only to low N use efficiency(NUE) but also to severe environmental pollution.Reducing N applic...Rational nitrogen(N) application can greatly increase rice(Oryza sativa L.) yield. However, excessive N input can lead not only to low N use efficiency(NUE) but also to severe environmental pollution.Reducing N application rate with a higher planting density(RNHD) is recommended to maintain rice yield and improve NUE. The effects of RNHD on fertilizer N fate and rice root growth traits remain unclear. We accordingly conducted a two-year field experiment to investigate the influence of RNHD on rice yield, fertilizer 15N fate, and root growth in a double-rice cropping system in China. In comparison with the conventional practice of high N application with sparse planting, RNHD resulted in similar yield and biomass production as well as plant N uptake. RNHD increased agronomic NUEs by 23.3%–31.9%(P < 0.05) and N recovery efficiency by 17.4%–24.1%(P < 0.05). RNHD increased fertilizer 15N recovery rate by 14.5%–34.7%(P < 0.05), but reduced15 N retention rate by 9.2%–12.0%(P < 0.05). Although a reduced N rate led to significantly reduced root length, surface area, volume, and biomass, these root traits were significantly increased by higher planting density. RNHD did not affect these root morphological traits and reduced activities of nitrate reductase(NR) and glutamine synthetase(GS) only at tillering stage. Plant N uptake was significantly positively correlated with these root traits, but not correlated with NR and GS activities. Together, these findings show that reducing N application with dense planting can lead to high plant N uptake by maintaining rice root growth and thus increase NUE.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
As one of the top three tuber crops of the world, cassava is a staple food and feed crop for tropical and subtropical regions. Because of its high drought resistance and tolerance to nutrient deficiency, cassava is us...As one of the top three tuber crops of the world, cassava is a staple food and feed crop for tropical and subtropical regions. Because of its high drought resistance and tolerance to nutrient deficiency, cassava is usually cultivated on hilly areas that are nutrient-poor. Nitrogen(N) is one of the significant factors affecting cassava yield. A double factorial(N level×genotypes) split-plot field experiment was conducted to analyze differences in yield and N accumulation of 25 cassava genotypes under low-N conditions to screen for cassava genotypes with high-N efficiency. The two-year field experiment showed that cassava yield and N accumulation are determined by specific genotypes, soil N levels, and year. Among these factors, soil N levels are the main factors that are responsible for differences in cassava yield. When yield and relative N accumulation under low-N conditions were used as screening markers, we identified an efficient and responsive genotype(SC10), and two inefficient and non-responsive genotypes(SC205 and GR5). The efficient and responsive genotype and the inefficient and non-responsive genotype can be used as study materials to further reveal the mechanisms for high-N efficiency in cassava.展开更多
The optimized nitrogen fertilization location differs in different rice-growing regions. We optimized nitrogen deep-point application in root-growing zone（NARZ） for transplanted rice in subtropical China. Field plot...The optimized nitrogen fertilization location differs in different rice-growing regions. We optimized nitrogen deep-point application in root-growing zone（NARZ） for transplanted rice in subtropical China. Field plot experiments were conducted over two years（2014–2015） in a double-rice cropping system to evaluate the effects of nitrogen（N） fertilizer location on grain yield and N use efficiency（NUE）. Four different nitrogen deep-point application methods（DN） were compared with traditional broadcast application（BN） using granular urea. The results showed that grain yield, recovery efficiency of N（REN）, agronomic efficiency of N（AEN）, and partial factor productivity of N（PFP_N） significantly increased 10.3–63.4, 13.7–56.7, 24.7–201.9 and 10.2–63.4%, respectively, in DN treatment compared to BN, respectively. We also find that DN treatments increased grain yield as well as grain N content, and thus grain quality, in comparison with conventional BN treatment. Correlation analysis indicated that significant improvement in grain yield and NUE mainly resulted from increases in productive panicle number and grain N content. In our proposed NARZ method, granular urea should be placed 0 to 5 cm around the rice seeding at a 12-cm depth druing rice transplanting. In NARZ, balanced application of N, P and K further improved grain yield and NUE over treatments with a single N deep-point application. High N uptake by the rice plant did not cause significant soil fertility depletion, demonstrating that this method could guarantee sustainable rice production.展开更多
Combining nitrification inhibitor and urea can improve crop yield and nitrogen(N)use efficiency(NUE).However,the inhibitor easily gets inactivated in soil,making it difficult to achieve the desired effect.To develop a...Combining nitrification inhibitor and urea can improve crop yield and nitrogen(N)use efficiency(NUE).However,the inhibitor easily gets inactivated in soil,making it difficult to achieve the desired effect.To develop a synergistic urea for increasing the inhibitor action time,soil N supply,and wheat growth,dicyandiamide(DCD)was coated after granulation with epoxy resin and then mixed with urea to develop new resin-coated DCD(RCD)synergistic urea.Scanning electron microscopy(SEM)and hydrostatic release tests were used to evaluate the membrane microstructure and the controlled-release performance of RCD.Five fertilization treatments were set up in the field:zero-N control(CK),urea(U),urea+common DCD particles(SUD1),urea+RCD(SUD2),and urea+both common DCD particles and RCD(3:7,weight/weight)(SUD3)to investigate the effects of the DCD synergistic urea on wheat growth,yield,and NUE and soil available N content.The SEM results showed that RCD had a complete coating,smooth surface,and small and rugged channels for DCD release in the profile.The hydrostatic release test at 25?C showed that the release period of DCD was extended to ten days due to resin coating.In the three DCD synergistic urea treatments,only SUD3 resulted in a significant increase in wheat yield(18.47%)compared with U.The NUE in SUD3 was significantly higher than those in SUD2,U,and SUD1.The treatment SUD3 had higher soil available N content than the other treatments during the key wheat growth stages,while effectively reducing the risk of soil nitrate leaching during wheat maturity.In summary,SUD3,a mixture of urea,DCD particles,and RCD,was the best treatment for significantly increasing wheat growth,yield,and NUE and soil N supply.展开更多
The creation of controlled-release urea (CRU) is a potent substitute for conventional fertilizers in order to preserve the availability of nitrogen (N) in soil,prevent environmental pollution,and move toward green agr...The creation of controlled-release urea (CRU) is a potent substitute for conventional fertilizers in order to preserve the availability of nitrogen (N) in soil,prevent environmental pollution,and move toward green agriculture.The main objectives of this study were to assess the impacts of CRU’s full application on maize production and to clarify the connection between the nutrient release pattern of CRU and maize nutrient uptake.In order to learn more about the effects of CRU application on maize yields,N uptake,mineral N (N_(min)) dynamics,N balance in soil-crop systems,and economic returns,a series of field experiments were carried out in 2018–2020 in Dalian City,Liaoning Province,China.There were 4 different treatments in the experiments:no N fertilizer input (control,CK);application of common urea at 210 kg ha^(-1)(U),the ideal fertilization management level for the study site;application of polyurethane-coated urea at the same N input rate as U (PCU);and application of PCU at a 20% reduction in N input rate (0.8PCU).Our findings showed that using CRU (i.e.,PCU and 0.8 PCU) may considerably increase maize N absorption,maintain maize yields,and increase N use efficiency (NUE) compared to U.The grain yield showed considerable positive correlations with total N uptake in leaf in U and 0.8 PCU,but negative correlations with that in PCU,indicating that PCU caused excessive maize absorption while 0.8 PCU could achieve a better yield response to N supply.Besides,PCU was able to maintain N fertilizer in the soil profile 0–20 cm away from the fertilization point,and higher N_(min)content was observed in the 0–20 cm soil layer at various growth stages,particularly at the middle and late growing stages,optimizing the temporal and spatial distributions of N_(min).Additionally,compared to that in U,the apparent N loss rate in PCU was reduced by 36.2%,and applying CRU (PCU and 0.8 PCU) increased net profit by 8.5% to 15.2% with less labor and fertilization frequency.It was concluded that using CRU could be an effective N fertilizer management strategy to sustain maize production,improve NUE,and increase economic returns while minimizing environmental risks.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
[Objective] The aim was to study on effects of N fertilizer on yield, N absorption and utilization of different cultivars of super high-yielding summer maize, in order to provide reference for reasonable N fertilizati...[Objective] The aim was to study on effects of N fertilizer on yield, N absorption and utilization of different cultivars of super high-yielding summer maize, in order to provide reference for reasonable N fertilization in accordance with different cultivars. [Method] Field experiment was conducted to study on effects of different N fertilizers on yield, N absorption and use efficiency of Zhengdan 958 and Xundan 20, in order to learn the effect differences at different N fertilizer levels. [Result] After N was applied, yields of the two summer maize increased significantly. Zhengdan 958 achieved the highest in yield and proceeds at 12 051.18 kg/hm2 and 1 722.40 yuan/hm2, respectively in low N level. In contrast, Xundan 20 achieved the highest at 13 166.00 kg/hm2 and 1 343.92 yuan/hm2 in the above two aspects in high N level. Compared with Zhengdan 958, Xundan 20 increased by 9.90%, 5.20% and 12.00% in N levels of 0, 240, and 450 kg/hm2, respectively. When N fertilizers were applied, protein yield of Xundan 20 was significantly higher than that of Zhengdan 958, so that higher N fertilizers contributed higher protein yield for Xundan 20. In high N level, N efficiency, N-fertilizer utilization and partial productivity of Xundan 20 were significantly higher than that of Zhengdan 958. [Conclusion] Lower N-fertilizer was suitable for Zhengdan 958 and Xundan 20 would get a good harvest if more N-fertilizers were applied. The results provided references for reasonable N fertilization.展开更多
Yield and N uptake of tomato (Lycopersicum esculentum Mill.) and pepper(Capsicum annuum L.) crops in five successive rotations receiving two compound fertilizers (12-12-17and 21-8-11 N-P_2O_5-K_2O) were studied to det...Yield and N uptake of tomato (Lycopersicum esculentum Mill.) and pepper(Capsicum annuum L.) crops in five successive rotations receiving two compound fertilizers (12-12-17and 21-8-11 N-P_2O_5-K_2O) were studied to determine 1) crop responses, 2) dynamics of NO_3-N andNH_4-N in different soil layers, 3) N balance and 4) system-level N efficiencies. Five treatments (2fertilizers, 2 fertilizer rates and a control), each with three replicates, were arranged in thestudy. The higher N fertilizer rate,300 kg N ha^(-1) (versus 150 kg N ha^(-1)), returned highervegetable fruit yields and total aboveground N uptake with the largest crop responses occurring forthe low-N fertilizer (12-12-17) applied at 300 kg N ha^(-1) rather than with the high-N fertilizer(21-8-11). Ammonium-N in the top 90 cm of the soil profile declined during the experiment, whilenitrate-N remained at a similar level throughout the experiment with the lower rate of fertilizer N.At the higher rate of N fertilizer there was a continuous NO_3-N accumulation of over 800 kg Nha^(-1). About 200 kg N ha^(-1) was applied with irrigation to each crop using NO_3-contaminatedgroundwater. In general, about 50% of the total N input was recovered from all treatments. Pepper,relative to tomato, used N more efficiently with smaller N losses, but the crops utilized less than29% of the fertilizer N over the two and a half-year period. Local agricultural practices maintainedhigh residual soil nutrient status. Thus, optimization of irrigation is required to minimizenitrate leaching and maximize crop N recovery.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
基金supported by the National Key Research and Development Program of China(2016YFD0300400)the National Basic Research Program of China(973 Program,2015CB150404)+4 种基金the Special Fund for Agroscientific Research in Public Interest of China(201203100)the National Key Technologies R&D Program of China during the 12th Five-year Plan period(2012BAD04B05)the Project of Shandong Province Higher Educational Science and Technology,China(J14LF12)the Shandong Province Mount Tai Industrial Talents Program,Chinathe Shandong Province Key Agricultural Project for Application Technology Innovation,China
文摘Straw return is an important management tool for tackling and promoting soil nutrient conservation and improving crop yield in Huang-Huai-Hai Plain, China. Although the incorporation of maize straw with deep plowing and rotary tillage practices are widespread in the region, only few studies have focused on rotation tillage. To determine the effects of maize straw return on the nitrogen （N） efficiency and grain yield of winter wheat （Triticum aestivum L.）, we conducted experiments in this region for 3 years. Five treatments were tested： （i） rotary tillage without straw return （RT）; （ii） deep plowing tillage without straw return （DT）; （iii） rotary tillage with total straw return （RS）; （iv） deep plowing tillage with total straw return （DS）; （v） rotary tillage of 2 years and deep plowing tillage in the 3rd year with total straw return （TS）. Treatments with straw return increased kernels no. ear-1, thousand-kernel weight （TKW）, grain yields, ratio of dry matter accumulation post-anthesis, and nitrogen （N） efficiency whereas reduced the ears no. ha-1 in the 2011-2012 and 2012-2013 growing seasons. Compared with the rotary tillage, deep plowing tillage significantly increased the grain yield, yield components, total dry matter accumulation, and N efficiency in 2013-2014. RS had significantly higher straw N distribution, soil inorganic nitrogen content, and soil enzymes activities in the 0-10 cm soil layer compared with the DS and TS. However, significantly lower values were ob- served in the 10-20 and 20-30 cm soil layers. TS obtained approximately equal grain yield as DS, and it also reduced the resource costs. Therefore, we conclude that TS is the most economical method for increasing grain yield and N efficiency of winter wheat in Huang-Huai-Hai Plain.
基金Project supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No.KZCX2-413-3)National Natural Science Foundation of China (No.30390080)National Basic Research Program of China (No.2005CB121108)
文摘Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N fertilizer treatments, applied in triplicate, were 0 （control）, 100, 200, 300, or 350 kg N ha^-1. After urea was applied to the surface water, a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field. Total N losses through ammonia volatilization generally increased with the N application rate, and the two higher N application rates （300 and 350 kg N ha^-1） showed a higher ratio of N lost through ammonia volatilization to applied N. Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N. Increasing the application rate generally decreased the ratio of N in the seed to N in the plant. For all N treatments, the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%. Surplus N with the highest N rate resulted in lodging of rice plants, a decreased rate of nitrogen fertilizer utilization, and reduced rice yields. Calculated from this experiment, the most economical N fertilizer application rate was 227 kg ha^-1 for the type of paddy soil in the Taihu Lake region. However, recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.
文摘Field trials on a silt-loamy paddy soil derived from shallow-sea deposit in direct seeding rice fields were conducted in Zhejiang, China, in 1996 to compare N efficiency of controlled release fertilizers (LP fertilizers) with the conventional urea. Six treatments including CK (no N fertilizer), conventional urea and different types of LP fertilizers at different rates were designed for two succeeding crops of early and late rice. A blend of different types of LP fertilizers as a single preplant "co-situs" application released N in a rate and amount synchronizing with uptake pattern of direct seeding rice. A single preplant application of the LP fertilizers could meet the N requirement of rice for the whole growth period without need of topdressing. Using LP fertilizer blends, equivalent grain yields could be maintained even if the N fertilization rates were reduced by 25%～50% compared with the conventional urea. Agronomic efficiency of the LP fertilizers was 13.6%～ 86.4% higher than that of the conventional urea in early rice and 100%～164.1% in late rice, depending on the amounts of the LP fertilizers applied. N fertilizer recovery rate increased from 27.4% for the conventional application of urea to 41.7%～54.l% for the single preplant "co-situs" application of the LP fertilizers. Use of the LP fertilizers was promising if the increase in production costs due to the high LP fertilizer prices could be compensated by increase in yield and N efficiency, reduction in labor costs and improvement in environment.
基金Supported by the National Basic Research Program of China(No 2012CB619303)the National High-Technology Research and Development Program of China(No 2011AA050514)
文摘We report on fabrication and photovoltaic characteristics of InxGa1-xN/GaN multiple quantum well solar cells with different indium compositions and barrier thicknesses. The as-grown samples are characterized by high- resolution x-ray diffraction and reciprocal space mapping. The results show that the sample with a thick barrier thickness （lO.Onm） and high indium composition （0.23） has better crystalline quality. In addition, the dark current density-voltage （J-V） measurement of this device shows a significant decrease of leakage current, which leads to high open-circuit voltage Vow. Through the J-V characteristics under an Air Mass 1.5 Global （AM 1.5 G） illumination, this device exhibits a Voc of 1.89 V, a short-circuit current density Ysc of 3.92mA/cm2 and a fill factor of 50.96%. As a result, the conversion efficiency （77） is enhanced to be 3.77% in comparison with other devices.
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the Special Fund for Agro-Scientific Research in the Public Interest in China (201103039)the Fundamental Research Funds for the Central Universities Key Projects, China (2013PY113)+1 种基金the Natural Science Foundation of Hubei Province, China (2013CFB203)the Research Funds of Huazhong Agricultural University, China (52209814032) for providing financial support
文摘Overestimation of nitrogen（N） uptake requirement is one of the driving forces of the overuse of N fertilization and the low efficiency of N use in China. In this study, we collected data from 1 844 site-years of rice（Oryza sativa L.） under various rotation cropping systems across the Yangtze River Valley. Selected treatments included without（N0 treatment） and with N application（N treatment） which were recommended by local technicians, with a wide grain range of 1.5–11.9 t ha–1. Across the 1 844 site-years, over 96% of the sites showed yield increase（relative yield〉105%） with N fertilization, and the increase rates decreased from 78.9 to 16.2% within the lowest range 〈4.0 to the highest 〉6.5 t ha–1. To produce one ton of grain, the rice absorbed approximately 17.8 kg N in the N0 treatment and 20.4 kg N in the N treatment. The value of partial factor productivity by N（PFP N） reached a range of 35.2–51.4 kg grain kg–1 with N application under the current recommended N rate. Averaged recovery rate of N（RE N） was above 36.0% in yields below 6.0 t ha–1 and lower than 31.7% in those above 6.0 t ha–1. Soil properties only affected yield increments within low rice yield levels（〈5.5 t ha–1）. There is a poor relationship between N application rates and indigenous nitrogen supply（INS）. From these observations and considering the local INS, we concluded there was a great potential for improvement in regional grain yield and N efficiency.
基金supported by the Modern Agricultural Industry Technology System of the Ministry of Agriculture of China(No.CARS-22-G-14)the Science and Technology Service Network Initiative of Chinese Academy of Sciences(No.KFJ-SW-STS-142)
文摘There is a need for rice cultivars with high yields and nitrogen(N) use efficiency(NUE), but with low cadmium(Cd) accumulation in Cd-contaminated paddy soils.To determine the relative effects of rice genotype, soil type, and Cd addition on rice grain yield and NUE, a pot experiment consisting of nine rice cultivars was conducted in two types of paddy soils, red soil(RS) and yellow soil(YS),without or with Cd spiked at 0.6 mg kg^(-1).The N supply was from both soil organic N pools and N fertilizers; thus, NUE was defined as the grain yield per unit of total crop-available N in the soil.Cd addition decreased grain yield and NUE in most rice cultivars,which was mainly related to reduced N uptake efficiency(NpUE, defined as the percentage of N taken up by the crop per unit of soil available N).However, Cd addition enhanced N assimilation efficiency(NtUE, defined as the grain yield per unit of N taken up by the crop) by 21.9% on average in all rice cultivars.The NpUE was mainly affected by soil type, whereas NtUE was affected by rice cultivar.Hybrid cultivars had higher NUEs than the japonica and indica cultivars because of their greater biomass and higher tolerance to Cd contamination.Reduction of NUE after Cd addition was stronger in RS than in YS, which was related to the lower absorption capacity for Cd in RS.Canonical correspondence analysis-based variation partitioning showed that cultivar type had the largest effect(34.4%) on NUE, followed by Cd addition(15.2%) and soil type(10.0%).
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 National Natural Science Foundation of China(31601263)the National Key Research and Development Program of China(2018YFD0301103)+2 种基金the China Postdoctoral Science Foundation(2017M622100)the Jiangxi Province Postdoctoral Science Foundation(2017KY11)the Open Foundation of Guangxi Key Laboratory of Rice Genetics and Breeding(160-380-16-2)。
文摘Rational nitrogen(N) application can greatly increase rice(Oryza sativa L.) yield. However, excessive N input can lead not only to low N use efficiency(NUE) but also to severe environmental pollution.Reducing N application rate with a higher planting density(RNHD) is recommended to maintain rice yield and improve NUE. The effects of RNHD on fertilizer N fate and rice root growth traits remain unclear. We accordingly conducted a two-year field experiment to investigate the influence of RNHD on rice yield, fertilizer 15N fate, and root growth in a double-rice cropping system in China. In comparison with the conventional practice of high N application with sparse planting, RNHD resulted in similar yield and biomass production as well as plant N uptake. RNHD increased agronomic NUEs by 23.3%–31.9%(P < 0.05) and N recovery efficiency by 17.4%–24.1%(P < 0.05). RNHD increased fertilizer 15N recovery rate by 14.5%–34.7%(P < 0.05), but reduced15 N retention rate by 9.2%–12.0%(P < 0.05). Although a reduced N rate led to significantly reduced root length, surface area, volume, and biomass, these root traits were significantly increased by higher planting density. RNHD did not affect these root morphological traits and reduced activities of nitrate reductase(NR) and glutamine synthetase(GS) only at tillering stage. Plant N uptake was significantly positively correlated with these root traits, but not correlated with NR and GS activities. Together, these findings show that reducing N application with dense planting can lead to high plant N uptake by maintaining rice root growth and thus increase NUE.
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provided by the Guangxi Natural Science Foundation,China(2014GXNSFAA118077 and 2018GXNSFDA281056)the Guangxi Postgraduate Innovative Education Research Program,China(YCBZ2017013 and YCSW2018039)。
文摘As one of the top three tuber crops of the world, cassava is a staple food and feed crop for tropical and subtropical regions. Because of its high drought resistance and tolerance to nutrient deficiency, cassava is usually cultivated on hilly areas that are nutrient-poor. Nitrogen(N) is one of the significant factors affecting cassava yield. A double factorial(N level×genotypes) split-plot field experiment was conducted to analyze differences in yield and N accumulation of 25 cassava genotypes under low-N conditions to screen for cassava genotypes with high-N efficiency. The two-year field experiment showed that cassava yield and N accumulation are determined by specific genotypes, soil N levels, and year. Among these factors, soil N levels are the main factors that are responsible for differences in cassava yield. When yield and relative N accumulation under low-N conditions were used as screening markers, we identified an efficient and responsive genotype(SC10), and two inefficient and non-responsive genotypes(SC205 and GR5). The efficient and responsive genotype and the inefficient and non-responsive genotype can be used as study materials to further reveal the mechanisms for high-N efficiency in cassava.
基金financially supported by the National Basic Research Program of China(2013CB127401)the National Natural Science Foundation of China(41401258)+1 种基金the Natural Science Foundation of Jiangsu Province,China(BK20131044)the Natural Science Foundation of Jiangxi Province,China(20142BAB214005)
文摘The optimized nitrogen fertilization location differs in different rice-growing regions. We optimized nitrogen deep-point application in root-growing zone（NARZ） for transplanted rice in subtropical China. Field plot experiments were conducted over two years（2014–2015） in a double-rice cropping system to evaluate the effects of nitrogen（N） fertilizer location on grain yield and N use efficiency（NUE）. Four different nitrogen deep-point application methods（DN） were compared with traditional broadcast application（BN） using granular urea. The results showed that grain yield, recovery efficiency of N（REN）, agronomic efficiency of N（AEN）, and partial factor productivity of N（PFP_N） significantly increased 10.3–63.4, 13.7–56.7, 24.7–201.9 and 10.2–63.4%, respectively, in DN treatment compared to BN, respectively. We also find that DN treatments increased grain yield as well as grain N content, and thus grain quality, in comparison with conventional BN treatment. Correlation analysis indicated that significant improvement in grain yield and NUE mainly resulted from increases in productive panicle number and grain N content. In our proposed NARZ method, granular urea should be placed 0 to 5 cm around the rice seeding at a 12-cm depth druing rice transplanting. In NARZ, balanced application of N, P and K further improved grain yield and NUE over treatments with a single N deep-point application. High N uptake by the rice plant did not cause significant soil fertility depletion, demonstrating that this method could guarantee sustainable rice production.
基金supported by the Major Agricultural Science and Technology Project of China(No.NK202218080315)the Project of Shandong Province Peanut Industry Technology System,China(No.SDAIT-04-06)。
文摘Combining nitrification inhibitor and urea can improve crop yield and nitrogen(N)use efficiency(NUE).However,the inhibitor easily gets inactivated in soil,making it difficult to achieve the desired effect.To develop a synergistic urea for increasing the inhibitor action time,soil N supply,and wheat growth,dicyandiamide(DCD)was coated after granulation with epoxy resin and then mixed with urea to develop new resin-coated DCD(RCD)synergistic urea.Scanning electron microscopy(SEM)and hydrostatic release tests were used to evaluate the membrane microstructure and the controlled-release performance of RCD.Five fertilization treatments were set up in the field:zero-N control(CK),urea(U),urea+common DCD particles(SUD1),urea+RCD(SUD2),and urea+both common DCD particles and RCD(3:7,weight/weight)(SUD3)to investigate the effects of the DCD synergistic urea on wheat growth,yield,and NUE and soil available N content.The SEM results showed that RCD had a complete coating,smooth surface,and small and rugged channels for DCD release in the profile.The hydrostatic release test at 25?C showed that the release period of DCD was extended to ten days due to resin coating.In the three DCD synergistic urea treatments,only SUD3 resulted in a significant increase in wheat yield(18.47%)compared with U.The NUE in SUD3 was significantly higher than those in SUD2,U,and SUD1.The treatment SUD3 had higher soil available N content than the other treatments during the key wheat growth stages,while effectively reducing the risk of soil nitrate leaching during wheat maturity.In summary,SUD3,a mixture of urea,DCD particles,and RCD,was the best treatment for significantly increasing wheat growth,yield,and NUE and soil N supply.
基金supported by the National Key R&D Program of China(No.2022YFD1700605)the National Natural Science Foundation of China(Nos.31872177 and31972511)the Fundamental Research Funds for Central Non-profit Scientific Institution,China(No.1610132-023005)。
文摘The creation of controlled-release urea (CRU) is a potent substitute for conventional fertilizers in order to preserve the availability of nitrogen (N) in soil,prevent environmental pollution,and move toward green agriculture.The main objectives of this study were to assess the impacts of CRU’s full application on maize production and to clarify the connection between the nutrient release pattern of CRU and maize nutrient uptake.In order to learn more about the effects of CRU application on maize yields,N uptake,mineral N (N_(min)) dynamics,N balance in soil-crop systems,and economic returns,a series of field experiments were carried out in 2018–2020 in Dalian City,Liaoning Province,China.There were 4 different treatments in the experiments:no N fertilizer input (control,CK);application of common urea at 210 kg ha^(-1)(U),the ideal fertilization management level for the study site;application of polyurethane-coated urea at the same N input rate as U (PCU);and application of PCU at a 20% reduction in N input rate (0.8PCU).Our findings showed that using CRU (i.e.,PCU and 0.8 PCU) may considerably increase maize N absorption,maintain maize yields,and increase N use efficiency (NUE) compared to U.The grain yield showed considerable positive correlations with total N uptake in leaf in U and 0.8 PCU,but negative correlations with that in PCU,indicating that PCU caused excessive maize absorption while 0.8 PCU could achieve a better yield response to N supply.Besides,PCU was able to maintain N fertilizer in the soil profile 0–20 cm away from the fertilization point,and higher N_(min)content was observed in the 0–20 cm soil layer at various growth stages,particularly at the middle and late growing stages,optimizing the temporal and spatial distributions of N_(min).Additionally,compared to that in U,the apparent N loss rate in PCU was reduced by 36.2%,and applying CRU (PCU and 0.8 PCU) increased net profit by 8.5% to 15.2% with less labor and fertilization frequency.It was concluded that using CRU could be an effective N fertilizer management strategy to sustain maize production,improve NUE,and increase economic returns while minimizing environmental risks.
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 Cooperation project of International Plant Nutrition Institution(IPNI)(NMBF-HenanAU-2007)Special Fund for Construction of National Modern Maize Industrial Technology System(nycytx-02-17)~~
文摘[Objective] The aim was to study on effects of N fertilizer on yield, N absorption and utilization of different cultivars of super high-yielding summer maize, in order to provide reference for reasonable N fertilization in accordance with different cultivars. [Method] Field experiment was conducted to study on effects of different N fertilizers on yield, N absorption and use efficiency of Zhengdan 958 and Xundan 20, in order to learn the effect differences at different N fertilizer levels. [Result] After N was applied, yields of the two summer maize increased significantly. Zhengdan 958 achieved the highest in yield and proceeds at 12 051.18 kg/hm2 and 1 722.40 yuan/hm2, respectively in low N level. In contrast, Xundan 20 achieved the highest at 13 166.00 kg/hm2 and 1 343.92 yuan/hm2 in the above two aspects in high N level. Compared with Zhengdan 958, Xundan 20 increased by 9.90%, 5.20% and 12.00% in N levels of 0, 240, and 450 kg/hm2, respectively. When N fertilizers were applied, protein yield of Xundan 20 was significantly higher than that of Zhengdan 958, so that higher N fertilizers contributed higher protein yield for Xundan 20. In high N level, N efficiency, N-fertilizer utilization and partial productivity of Xundan 20 were significantly higher than that of Zhengdan 958. [Conclusion] Lower N-fertilizer was suitable for Zhengdan 958 and Xundan 20 would get a good harvest if more N-fertilizers were applied. The results provided references for reasonable N fertilization.
基金Project supported by the National Natural Science Foundation of China (No. 30230250) and the Royal Society of London (No. 15360).
文摘Yield and N uptake of tomato (Lycopersicum esculentum Mill.) and pepper(Capsicum annuum L.) crops in five successive rotations receiving two compound fertilizers (12-12-17and 21-8-11 N-P_2O_5-K_2O) were studied to determine 1) crop responses, 2) dynamics of NO_3-N andNH_4-N in different soil layers, 3) N balance and 4) system-level N efficiencies. Five treatments (2fertilizers, 2 fertilizer rates and a control), each with three replicates, were arranged in thestudy. The higher N fertilizer rate,300 kg N ha^(-1) (versus 150 kg N ha^(-1)), returned highervegetable fruit yields and total aboveground N uptake with the largest crop responses occurring forthe low-N fertilizer (12-12-17) applied at 300 kg N ha^(-1) rather than with the high-N fertilizer(21-8-11). Ammonium-N in the top 90 cm of the soil profile declined during the experiment, whilenitrate-N remained at a similar level throughout the experiment with the lower rate of fertilizer N.At the higher rate of N fertilizer there was a continuous NO_3-N accumulation of over 800 kg Nha^(-1). About 200 kg N ha^(-1) was applied with irrigation to each crop using NO_3-contaminatedgroundwater. In general, about 50% of the total N input was recovered from all treatments. Pepper,relative to tomato, used N more efficiently with smaller N losses, but the crops utilized less than29% of the fertilizer N over the two and a half-year period. Local agricultural practices maintainedhigh residual soil nutrient status. Thus, optimization of irrigation is required to minimizenitrate leaching and maximize crop N recovery.
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.
