The traditional prediction methods of element yield rate can be divided into experience method and data-driven method.But in practice,the experience formulae are found to work only under some specific conditions,and t...The traditional prediction methods of element yield rate can be divided into experience method and data-driven method.But in practice,the experience formulae are found to work only under some specific conditions,and the sample data that are used to establish data-driven models are always insufficient.Aiming at this problem,a combined method of genetic algorithm(GA) and adaptive neuro-fuzzy inference system(ANFIS) is proposed and applied to element yield rate prediction in ladle furnace(LF).In order to get rid of the over reliance upon data in data-driven method and act as a supplement of inadequate samples,smelting experience is integrated into prediction model as fuzzy empirical rules by using the improved ANFIS method.For facilitating the combination of fuzzy rules,feature construction method based on GA is used to reduce input dimension,and the selection operation in GA is improved to speed up the convergence rate and to avoid trapping into local optima.The experimental and practical testing results show that the proposed method is more accurate than other prediction methods.展开更多
This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in...This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup>) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup> plots exhibiting the lowest and highest grain yields of 1238 kg∙ha<sup>−</sup><sup>1</sup> and 2098 kg∙ha<sup>−</sup><sup>1</sup>, respectively. Variety and nitrogen effects on partial factor productivity (PFP<sub>N</sub>), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFP<sub>N</sub> (41.3 kg grain kg<sup>−</sup><sup>1</sup>∙N) and AEN (29.4 kg grain kg<sup>−</sup><sup>1</sup>∙N) were obtained in the 30 kg∙N∙ha<sup>−</sup><sup>1</sup> plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL<sup>−</sup><sup>1</sup> spent on N) were obtained in the 180 kg∙N∙ha<sup>−</sup><sup>1</sup>. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.展开更多
NH_(3),derived from electrocatalytic nitrogen reduction reaction(NRR),is promising to satisfy the need of food production and serve as a carbon-free liquid energy carrier in the near future.Yet major challenges remain...NH_(3),derived from electrocatalytic nitrogen reduction reaction(NRR),is promising to satisfy the need of food production and serve as a carbon-free liquid energy carrier in the near future.Yet major challenges remain in enhancing NH_(3) yield rate and conversion efficiency of available electrocatalysts.This work achieved an ultrahigh electrocatalytic NH_(3)yield rate on the_(0.50)Fe-Bi_(2)W0_(6) catalyst by a facile Fe-doped strategy.Up to 289μg·h^(-1)·mg_(cat)^(-1) of NH_(3) formation rate was obtained at-0.75 V vs.RHE,which was reliably quantized by indophenol blue and ^(1)H NMR methods.The impressive result is an order of magnitude higher than that of the reported Fe-and Bi-based catalysts,even more superior than the result of single atom Ru catalyst.The key of the outstanding NRR behaviors on the_(0.50)Fe-Bi_(2)W0_(6) catalyst is the significant hydrogen evolution reaction(HER)suppression and the synergy between Bi and Fe,which can effectively modulate the electron distribution and accelerate the electron transport.This work endows a new insight to further explore the high-performance electrocatalysts toward NRR.展开更多
Excessive nitrogen(N) fertilization in intensive agricultural areas such as the plain region of South China has resulted in low nitrogen use efficiency and serious environmental problems. To determine the optimum N ...Excessive nitrogen(N) fertilization in intensive agricultural areas such as the plain region of South China has resulted in low nitrogen use efficiency and serious environmental problems. To determine the optimum N application rate, grain yield, apparent nitrogen recovery efficiency(ANRE), apparent N loss, and ammonium(NH_3) volatilization under different N application rates in the three years from 2012 to 2014 were studied. The results showed that the relationship between grain yields and N application rate in the three years were well fitted by quadratic equations. When N application rate reached 197 kg ha^(–1) in 2012, 199 kg ha^(–1) in 2013 and 196 kg ha^(–1) in 2014, the plateau of the grain yields appeared. With the increase of N application rate, the ANRE for rice decreased which could be expressed with sigmoidal equation; when N application rate was 305 kg ha^(–1) in 2012, 275 kg ha^(–1) in 2013 and 312 kg ha^(–1) in 2014, the curves of ANRE appeared turing points. Besides, the relationship between soil Nresidual and N application rate was fitted by the quadratic equation and the maximums of soil Nresidual were reached in the three years with the N application rate of 206, 244 and 170 kg ha^(–1), respectively. Statistical analysis indicated that NH3 volatilization and apparent N loss in three years all increased with the increasing N application rate. When the amount of NH3 volatilization increased to 11.6 kg N ha^(–1) in 2012, 40.5 kg N ha^(–1) in 2013 and 57.0 kg N ha^(–1)in 2014, the apparent N loss in the three years had obvious increase. To determine the optimum N application rate, the average N application on the plateau of the grain yield was considered as the lower limit while the average N application rate at the turning points of ANRE, the residual N in soil and apparent N loss was taken as the upper limit. According to the results in three years, the optimum N application rate for rice in Zhejiang was 197–255 kg ha^(–1).展开更多
A field experiment was carried out to investigate the effects of different emitter discharge rates under drip irrigation on soil salinity distribution and cotton yield in an extreme arid region of Tarim River catchmen...A field experiment was carried out to investigate the effects of different emitter discharge rates under drip irrigation on soil salinity distribution and cotton yield in an extreme arid region of Tarim River catchment in Northwest China. Four treatments of emitter discharge rates, i.e. 1.8, 2.2, 2.6 and 3.2 L/h, were designed under drip irrigation with plastic mulch in this paper. The salt distribution in the range of 70-cm horizontal distance and 100-cm vertical distance from the emitter was measured and analyzed during the cotton growing season. The soil salinity is expressed in terms of electrical conductivity (dS/m) of the saturated soil extract (ECe), which was measured using Time Domain Reflector (TDR) 20 times a year, including 5 irrigation events and 4 measured times before/after an irrigation event. All the treatments were repeated 3 times. The groundwater depth was observed by SEBA MDS Dipper 3 automatically at three experimental sites. The results showed that the order of reduction in averaged soil salinity was 2.6 L/h 〉 2.2 L/h 〉 1.8 L/h 〉 3.2 L/h after the completion of irrigation for the 3-year cotton growing season. Therefore, the choice of emitter discharge rate is considerably important in arid silt loam. Usually, the ideal emitter discharge rate is 2.4-3.0 L/h for soil desalinization with plastic mulch, which is advisable mainly because of the favorable salt leaching of silt loam and the climatic conditions in the studied arid area. Maximum cotton yield was achieved at the emitter discharge rate of 2.6 L/h under drip irrigation with plastic mulch in silty soil at the study site. Hence, the emitter discharge rate of 2.6 L/h is recommended for drip irrigation with plastiic mulch applied in silty soil in arid regions.展开更多
A total of nine soybean (Glycine max (L.) Merr.) cultivars were divided into three yield levels which were planted under the same environmental condition. The net photosynthetic rate was measured by LI-6400 portab...A total of nine soybean (Glycine max (L.) Merr.) cultivars were divided into three yield levels which were planted under the same environmental condition. The net photosynthetic rate was measured by LI-6400 portable photosynthesis system. The chlorophyll content and specific leaf weight were measured with regular methods. The results showed that the specific leaf weight, chlorophyll content and net photosynthetic rate of high yield varieties were higher than those of low yield varieties. The yield had a significantly positive correlation with the net photosynthetic rate. With the improvement of modem technology, the net photosynthetic rate could be measured quickly and exactly. Hence, net photosynthetic rate could be used as an effective index in the selection of high yield soybean.展开更多
[Objective] The paper was to study the effect of tobacco blown spot on the yield and output value of tobacco leaf.[Method]The upper,middle and lower leaves in tobacco plant were selected during the harvest period of t...[Objective] The paper was to study the effect of tobacco blown spot on the yield and output value of tobacco leaf.[Method]The upper,middle and lower leaves in tobacco plant were selected during the harvest period of tobacco to carry out loss rate estimation of yield and output value of tobacco leaf caused by different disease levels of brown spot.Regression correlation analysis was also conducted.[Result]The disease levels of brown spot had extremely significant strong negative correlation with single leaf weight of tobacco leaf,and it had extremely significant strong positive correlation with the loss rate of single leaf weight.The increase speed of loss rate of single leaf weight of middle and upper leaves was obviously faster than that of lower leaves.The loss rates of single leaf weight of upper,middle and lower leaves were 3.18%-28.95%,3.43%-28.88% and 10.07%-26.90%,respectively.The higher the disease level of blown spot was,the lower the yield and output value of tobacco leaf was,and the corresponding loss rate was also higher.Correlation analysis showed that the disease level of blown spot had extremely significant strong negative correlation with the yield and output value of tobacco leaf,and it had extremely significant strong positive correlation with the loss rate of yield and output value.The negative impact of blown spot on the output value of tobacco leaf was far greater than that on the yield.The highest loss rate of the yield of tobacco leaf was 28.56%,while the highest loss rate of output value reached 89.67%.[Conclusion] The study provided theoretical basis for accurately holding the critical period for the control of blown spot,thus reducing the damage on tobacco leaf and improving the output value of tobacco leaf.展开更多
Double-seed sowing(two seeds per hole)is the dominant pattern of peanut sowing in China,but within-hole plant competition usually limits their growth and yield formation.Besides,the traditional double-seed sowing meth...Double-seed sowing(two seeds per hole)is the dominant pattern of peanut sowing in China,but within-hole plant competition usually limits their growth and yield formation.Besides,the traditional double-seed sowing method does not facilitate mechanization during sowing.The objective of this study was to determine if single-seed sowing at a proper seeding rate yielded better than traditional double-seed sowing pattern and the differences of physiological metabolism of roots.A field experiment was conducted in two consecutive years to compare pod yields of single-seed sowing at 180000(S180),225000(S225),and 270000 seeds ha^-1(S270)with that of double-seed sowing at 270000 seeds ha^-1(D270)using a completely randomized block design with four replications.And the root bleeding sap rate,nutrient content,and the main hormone contents in root bleeding sap were also comparatively investigated.Although the pod yields of single-seed sowing at the three densities were higher than that of traditional double-seed sowing(D270),S225 yielded better than the other two single-seed sowing treatments(S180 and S270).The increased pod yield in single-seed sowing at 225000 seeds ha^-1 was mainly due to the higher pod dry weight per plant and harvest index.The improved pod dry weight and shoot growth had closely relationship with the enhanced root physiological traits such as the increased root bleeding sap rate,content of free amino acids,soluble sugars,K^+,Mg^2+,Zn^2+,and Ca^2+of the individual plant root.The improved activity of root reductive,nitrate reductase(NR)and ATPase and higher zeatin and zeatin riboside(Z+ZR)content of root bleeding sap were alsocrucial to the pod and shoot growth of peanut.Single-seed sowing at a moderate seeding rate(S225)is a potential practice to increase pod yield and to save seed cost.展开更多
Excessive use of N fertilizer in intensive agriculture can increase crop yield and at the same time cause high carbon(C) emissions.This study was conducted to determine optimized N fertilizer application for high gr...Excessive use of N fertilizer in intensive agriculture can increase crop yield and at the same time cause high carbon(C) emissions.This study was conducted to determine optimized N fertilizer application for high grain yield and lower C emissions in summer corn(Zea mays L.).A field experiment, including 0(N0), 75(N75), 150(N150), 225(N225), and 300(N300) kg N ha–1 treatments, was carried out during 2010–2012 in the North China Plain(NCP).The results showed that grain yield, input energy, greenhouse gas(GHG) emissions, and carbon footprint(CF) were all increased with the increase of N rate, except net energy yield(NEY).The treatment of N225 had the highest grain yield(10 364.7 kg ha–1) and NEY(6.8%), but the CF(0.25) was lower than that of N300, which indicates that a rate of 225 kg N ha–1 can be optimal for summer corn in NCP.Comparing GHG emision compontents, N fertilizer(0–51.1%) was the highest and followed by electricity for irrigation(19.73–49.35%).We conclude that optimazing N fertilizer application rate and reducing electricity for irrigation are the two key measures to increase crop yield, improve energy efficiency and decrease GHG emissions in corn production.展开更多
Using cottonseed hull as the control substrate, different proportions of the untreated and treated Carya cathayensis Sarg shells were added to cultivation of Pleurotus geesteranus. The mycelial growth rate, yield, nut...Using cottonseed hull as the control substrate, different proportions of the untreated and treated Carya cathayensis Sarg shells were added to cultivation of Pleurotus geesteranus. The mycelial growth rate, yield, nutritional composition and contents of heavy metals of the Pleurotus geesteranus cultivated on these substrates were determined. The results suggest that added to treated Carya cathayensis Sarg shell promoted the mycelial growth and increased the yield, biological efficiency and the contents of crude fiber, ash, amino acids and essential amino acids of Pleurotus geesteranus. In addition, the fat content and soluble sugar contents of Pleurotus geesteranus were decreased with the increase of the Carya cathayensis Sarg shell content in substrate, but their contents of heavy metals including mercury (Hg), arsenic (As), cadmium (Cd) and lead (Pb) were higher than that obtained on control substrate.展开更多
In Haigh Westergaard stress space linear combination of twin shear stress and Tresca yield functions is called the mean yield (MY) criterion. The mathematical relationship of the criterion and its plastic work rate ...In Haigh Westergaard stress space linear combination of twin shear stress and Tresca yield functions is called the mean yield (MY) criterion. The mathematical relationship of the criterion and its plastic work rate done per unit volume were derived. A generalized worked example of slab forging was analyzed by the criterion and its corresponding plastic work rate done per unit volume. Then, the precision of the solution was compared with those by Mises and Twin shear stress yield criterions, respectively. It turned out that the calculated results by MY criterion were in good agreement with those by Mises criterion.展开更多
The objective of this study was to identify the response of grain yield to plant density and nitrogen rate in spring maize hybrids released from 1970 to 2010 and grown extensively in Northeast China.Twenty-one hybrids...The objective of this study was to identify the response of grain yield to plant density and nitrogen rate in spring maize hybrids released from 1970 to 2010 and grown extensively in Northeast China.Twenty-one hybrids were grown for 2 years in Northeast China at densities of 30,000,52,500,75,000,and 97,500 plants ha^(-1)and N application levels of 0,150,300,and 450 kg N ha^(-1).Irrespective of density or nitrogen application rate,grain yields both per plant and per unit area were significantly higher for newer than older hybrids.As plant density increased from 30,000 to 97,500 plant ha^(-1),yield per plant of 1970 s,1980 s,1990 s,and 2000 s hybrids decreased by 50%,45%,46%,and 52%,respectively.The response of grain yield per unit area to plant density was curvilinear.The estimated optimum plant densities were about 58,000,49,000,65,000,and 65,000 plants ha^(-1)for hybrids released in the 1970 s,1980s,1990 s,and 2000 s,respectively.The theoretical optimum densities for the hybrids released from the 1970 s to the 2000 s increased by 1750 plants ha^(-1)decade^(-1).Nitrogen fertilization significantly increased grain yields per plant and per unit area for all hybrids.The theoretical optimum N application rates for high yield for hybrids released in the 1970 s and 1980 s were about 280 and 360 kg ha^(-1),and the hybrids from the 1990 s and 2000 s showed highest yield at 330 kg ha^(-1)N.No significant difference in the grain yields of 2000 s hybrids between the N levels of 150 to 450 kg ha^(-1)was found.Significant yield gains per plant and per unit area were found,with average increases of 17.9 g plant^(-1)decade^(-1)and936 kg ha^(-1)decade^(-1)over the period 1970–2010,respectively.Yield gains were attributed mainly to increased yield per plant,contributed by increases in kernel number per ear and1000-kernel weight.The rates of lodging and barren plants of newer hybrids were significantly lower than those of older ones,especially at high plant density.展开更多
In order to overcome the nonlinearity of Mises criterion, a new linear yield criterion with a dodecagon shape of the same perimeter as Mises criterion was derived by means of geometrical analysis. Its specific plastic...In order to overcome the nonlinearity of Mises criterion, a new linear yield criterion with a dodecagon shape of the same perimeter as Mises criterion was derived by means of geometrical analysis. Its specific plastic work rate expressed as a linear function of the yield stress, the maximum and minimum strains was also deduced and compared with that of Mises criterion. The physical meaning of the proposed yield criterion is that yielding of materials begins when the shear yield stress τs reaches the magnitude of 0.594σs. By introducing the Lode parameter, validation of evolution expressions of the proposed yield criterion with those based on Tresca, Mises and TSS criteria as well as available classical yield experimental results of various metals shows that the present results intersect with Mises results and coincide well with experimental data. Moreover, further application to the limit analysis of circle plate as an example is performed to demonstrate the effectiveness of the proposed yield criterion, and the subsequent comparison of limit loads with the Tresca analytical solutions and Mises numerical results shows that the present results are higher than the Tresca analytical results, and are in good agreement with the Mises numerical results.展开更多
The mechanism of the critical strain of serrated yielding is studied via tension tests at various strain rates. Betore the critical strain, it is deduced that dislocations are not pinned at high strain rates, and disl...The mechanism of the critical strain of serrated yielding is studied via tension tests at various strain rates. Betore the critical strain, it is deduced that dislocations are not pinned at high strain rates, and dislocations at low strain rates are pinned but cannot escape. The critical strain depends on the first pinning process at high strain rates and on the first unpinning process at low strain rates. The calculated results based on the two criteria are in good consistency with the experiment.展开更多
Based on theoretical analysis of crop risk and premium rate setting,we take the case of premium rate setting of insurance on cotton yield in Shache County,Shaya County and Aksu City of Xinjiang.Using parametric method...Based on theoretical analysis of crop risk and premium rate setting,we take the case of premium rate setting of insurance on cotton yield in Shache County,Shaya County and Aksu City of Xinjiang.Using parametric methods and insurance actuarial technique,we select the optimal model for risk fitting of cotton yield in three areas;compare the premium rate calculated accurately under four risk distribution assumptions of cotton yield,and the rational premium rate,to analyze the impact of risk distribution of crop yield on premium rate setting.The empirical results show that the Logistic distribution is the optimal distribution for risk fitting of cotton yield in three areas;the rational net premium rate of cotton insurance in three areas is 7.62%,6.32% and 4.96%,respectively;there are errors in premium rate setting under assumptions of normal distribution,normalized skew distribution and Weibull distribution,ranging from 0.2 percentage points to 8 percentage points.Thus,it indicates that the selection of risk distribution model of yield directly affects the accuracy of premium rate setting of crops,and the key to accurate premium rate setting of crops lies in correct selection of risk distribution model of yield.展开更多
The effects of calcium application rate on dry matter accumulation and yield of peanut were studied under high-yielding field condition. The variety used for the study was Tang A8252( Spanish peanut). The results show...The effects of calcium application rate on dry matter accumulation and yield of peanut were studied under high-yielding field condition. The variety used for the study was Tang A8252( Spanish peanut). The results showed that number of full fruit,dry weight per plant,kernel yield,and pod yield all increased with calcium application increased,and they decreased when calcium application rate was more than150 kg/ha. Both the height of main stem and the length of side shoot decreased with calcium application increased. Therefore,to obtain the optimal agronomic character index and the highest yield benefit,the suggested calcium application rate would be 150 kg/ha for peanut.展开更多
Sowing date and seeding rate are critical for productivity of winter wheat(Triticum aestivum L.).A three-year field experiment was conducted with three sowing dates(20 September(SD1),1 October(SD2),and 10 October(SD3)...Sowing date and seeding rate are critical for productivity of winter wheat(Triticum aestivum L.).A three-year field experiment was conducted with three sowing dates(20 September(SD1),1 October(SD2),and 10 October(SD3)) and three seeding rates(SR67.5,SR90,and SR112.5) to determine suitable sowing date and seeding rate for high wheat yield.A large seasonal variation in accumulated temperature from sowing to winter dormancy was observed among three growing seasons.Suitable sowing dates for strong seedlings before winter varied with the seasons,that was SD2 in 2012–2013,SD3 in 2013–2014,and SD2 as well as SD1 in 2014–2015.Seasonal variation in precipitation during summer fallow also had substantial effects on soil water storage,and consequently influenced grain yield through soil water consumption from winter dormancy to maturity stages.Lower consumption of soil water from winter dormancy to booting stages could make more water available for productive growth from anthesis to maturity stages,leading to higher grain yield.SD2 combined with SR90 had the lowest soil water consumption from winter dormancy to booting stages in 2012–2013 and 2014–2015; while in 2013–2014,it was close to that with SR67.5 or SR112.5.For productive growth from anthesis to maturity stages,SD2 with SR90 had the highest soil water consumption in all three seasons.The highest water consumption in the productive growth period resulted in the best grain yield in both low and high rainfall years.Ear number largely contributed to the seasonal variation in grain yield,while grain number per ear and 1 000-grain weight also contributed to grain yield,especially when soil water storage was high.Our results indicate that sowing date and seeding rate affect grain yield through seedling development before winter and also affect soil water consumption in different growth periods.By selecting the suitable sowing date(1 October) in combination with the proper seeding rate of 90 kg ha–1,the best yield was achieved.Based on these results,we recommend that the current sowing date be delayed from 22 or 23 September to 1 October.展开更多
To understand the high strain rate deformation mechanism and determine the grain size,strain rate and porosity dependent yield strength of nanocrystalline materials,a new mechanical model based on the deformation mech...To understand the high strain rate deformation mechanism and determine the grain size,strain rate and porosity dependent yield strength of nanocrystalline materials,a new mechanical model based on the deformation mechanism of nanocrystalline materials under high strain rate loading was developed.As a first step of the research,the yield behavior of the nanocrystalline materials under high strain rate loading was mainly concerned in the model and uniform deformation was assumed for simplification.Nanocrystalline materials were treated as composites consisting of grain interior phase and grain boundary phase,and grain interior and grain boundary deformation mechanisms under high strain rate loading were analyzed,then Voigt model was applied to coupling grain boundary constitutive relation with mechanical model for grain interior phase to describe the overall yield mechanical behavior of nanocrystalline materials.The predictions by the developed model on the yield strength of nanocrysatlline materials at high strain rates show good agreements with various experimental data.Further discussion was presented for calculation results and relative experimental observations.展开更多
The nitrogen uptake, yield and its components for two super-high-yielding hybrid rice combinations, Guodao 6 and Eryou 7954 were investigated under different plant densities (15, 18, and 21 plants/m^2) and different...The nitrogen uptake, yield and its components for two super-high-yielding hybrid rice combinations, Guodao 6 and Eryou 7954 were investigated under different plant densities (15, 18, and 21 plants/m^2) and different nitrogen application rates (120, 150, 180, and 210 kg/hm^2). The experiment was conducted on loam soil during 2004-2006 at the experimental farm of the China National Rice Research Institute in Hangzhou, China. In these years, the two hybrid rice cleady showed higher yield at a plant density of 15 plants/m^2 with a nitrogen application rate of 180 kg/hm^2. Guodao 6 produced an average grain yield of 10 215.6 kg/hm^2 across the three years, while the yield of Eryou 7954 was 9 633.0 kg/hm^2. With fewer plants per unit-area and larger plants in the plots, the two hybrid rice produced more panicles per plant in three years. The highest nitrogen uptake of the two hybrid rice was at a plant density of 15 plants/m^2 with a nitrogen application rate of 180 kg/hm^2. Further increasing nitrogen application rate was not advantageous for nitrogen uptake in super-high-yielding rice under the same plant density.展开更多
基金Projects(2007AA041401,2007AA04Z194) supported by the National High Technology Research and Development Program of China
文摘The traditional prediction methods of element yield rate can be divided into experience method and data-driven method.But in practice,the experience formulae are found to work only under some specific conditions,and the sample data that are used to establish data-driven models are always insufficient.Aiming at this problem,a combined method of genetic algorithm(GA) and adaptive neuro-fuzzy inference system(ANFIS) is proposed and applied to element yield rate prediction in ladle furnace(LF).In order to get rid of the over reliance upon data in data-driven method and act as a supplement of inadequate samples,smelting experience is integrated into prediction model as fuzzy empirical rules by using the improved ANFIS method.For facilitating the combination of fuzzy rules,feature construction method based on GA is used to reduce input dimension,and the selection operation in GA is improved to speed up the convergence rate and to avoid trapping into local optima.The experimental and practical testing results show that the proposed method is more accurate than other prediction methods.
文摘This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup>) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup> plots exhibiting the lowest and highest grain yields of 1238 kg∙ha<sup>−</sup><sup>1</sup> and 2098 kg∙ha<sup>−</sup><sup>1</sup>, respectively. Variety and nitrogen effects on partial factor productivity (PFP<sub>N</sub>), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFP<sub>N</sub> (41.3 kg grain kg<sup>−</sup><sup>1</sup>∙N) and AEN (29.4 kg grain kg<sup>−</sup><sup>1</sup>∙N) were obtained in the 30 kg∙N∙ha<sup>−</sup><sup>1</sup> plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL<sup>−</sup><sup>1</sup> spent on N) were obtained in the 180 kg∙N∙ha<sup>−</sup><sup>1</sup>. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.
基金supported by the National Natural Science Foundation of China(Nos.21675151,21705145 and 21721003)the Ministry of Science and Technology of China(No.2016YFA0203203).
文摘NH_(3),derived from electrocatalytic nitrogen reduction reaction(NRR),is promising to satisfy the need of food production and serve as a carbon-free liquid energy carrier in the near future.Yet major challenges remain in enhancing NH_(3) yield rate and conversion efficiency of available electrocatalysts.This work achieved an ultrahigh electrocatalytic NH_(3)yield rate on the_(0.50)Fe-Bi_(2)W0_(6) catalyst by a facile Fe-doped strategy.Up to 289μg·h^(-1)·mg_(cat)^(-1) of NH_(3) formation rate was obtained at-0.75 V vs.RHE,which was reliably quantized by indophenol blue and ^(1)H NMR methods.The impressive result is an order of magnitude higher than that of the reported Fe-and Bi-based catalysts,even more superior than the result of single atom Ru catalyst.The key of the outstanding NRR behaviors on the_(0.50)Fe-Bi_(2)W0_(6) catalyst is the significant hydrogen evolution reaction(HER)suppression and the synergy between Bi and Fe,which can effectively modulate the electron distribution and accelerate the electron transport.This work endows a new insight to further explore the high-performance electrocatalysts toward NRR.
基金supported by the National Natural Science Foundation of China(41501238)the Key Technologies R&D Program of China during the 12th Five-Year Plan period(2015BAD23B03)the Special Fund for Agro-scientific Research in the Public Interest from the Ministry of Agriculture,China(201003014-02-08)
文摘Excessive nitrogen(N) fertilization in intensive agricultural areas such as the plain region of South China has resulted in low nitrogen use efficiency and serious environmental problems. To determine the optimum N application rate, grain yield, apparent nitrogen recovery efficiency(ANRE), apparent N loss, and ammonium(NH_3) volatilization under different N application rates in the three years from 2012 to 2014 were studied. The results showed that the relationship between grain yields and N application rate in the three years were well fitted by quadratic equations. When N application rate reached 197 kg ha^(–1) in 2012, 199 kg ha^(–1) in 2013 and 196 kg ha^(–1) in 2014, the plateau of the grain yields appeared. With the increase of N application rate, the ANRE for rice decreased which could be expressed with sigmoidal equation; when N application rate was 305 kg ha^(–1) in 2012, 275 kg ha^(–1) in 2013 and 312 kg ha^(–1) in 2014, the curves of ANRE appeared turing points. Besides, the relationship between soil Nresidual and N application rate was fitted by the quadratic equation and the maximums of soil Nresidual were reached in the three years with the N application rate of 206, 244 and 170 kg ha^(–1), respectively. Statistical analysis indicated that NH3 volatilization and apparent N loss in three years all increased with the increasing N application rate. When the amount of NH3 volatilization increased to 11.6 kg N ha^(–1) in 2012, 40.5 kg N ha^(–1) in 2013 and 57.0 kg N ha^(–1)in 2014, the apparent N loss in the three years had obvious increase. To determine the optimum N application rate, the average N application on the plateau of the grain yield was considered as the lower limit while the average N application rate at the turning points of ANRE, the residual N in soil and apparent N loss was taken as the upper limit. According to the results in three years, the optimum N application rate for rice in Zhejiang was 197–255 kg ha^(–1).
基金supported by the National Basic Research Program of China (2009CB421302)the National Natural Science Foundation of China (41071026,51069017)
文摘A field experiment was carried out to investigate the effects of different emitter discharge rates under drip irrigation on soil salinity distribution and cotton yield in an extreme arid region of Tarim River catchment in Northwest China. Four treatments of emitter discharge rates, i.e. 1.8, 2.2, 2.6 and 3.2 L/h, were designed under drip irrigation with plastic mulch in this paper. The salt distribution in the range of 70-cm horizontal distance and 100-cm vertical distance from the emitter was measured and analyzed during the cotton growing season. The soil salinity is expressed in terms of electrical conductivity (dS/m) of the saturated soil extract (ECe), which was measured using Time Domain Reflector (TDR) 20 times a year, including 5 irrigation events and 4 measured times before/after an irrigation event. All the treatments were repeated 3 times. The groundwater depth was observed by SEBA MDS Dipper 3 automatically at three experimental sites. The results showed that the order of reduction in averaged soil salinity was 2.6 L/h 〉 2.2 L/h 〉 1.8 L/h 〉 3.2 L/h after the completion of irrigation for the 3-year cotton growing season. Therefore, the choice of emitter discharge rate is considerably important in arid silt loam. Usually, the ideal emitter discharge rate is 2.4-3.0 L/h for soil desalinization with plastic mulch, which is advisable mainly because of the favorable salt leaching of silt loam and the climatic conditions in the studied arid area. Maximum cotton yield was achieved at the emitter discharge rate of 2.6 L/h under drip irrigation with plastic mulch in silty soil at the study site. Hence, the emitter discharge rate of 2.6 L/h is recommended for drip irrigation with plastiic mulch applied in silty soil in arid regions.
基金Supported by the National Natural Science Foundation of China (30871547)Foundation of Department of Education of Jilin Province (2006041)Scientific Research Foundation of Jilin Agricultural University (2009028)
文摘A total of nine soybean (Glycine max (L.) Merr.) cultivars were divided into three yield levels which were planted under the same environmental condition. The net photosynthetic rate was measured by LI-6400 portable photosynthesis system. The chlorophyll content and specific leaf weight were measured with regular methods. The results showed that the specific leaf weight, chlorophyll content and net photosynthetic rate of high yield varieties were higher than those of low yield varieties. The yield had a significantly positive correlation with the net photosynthetic rate. With the improvement of modem technology, the net photosynthetic rate could be measured quickly and exactly. Hence, net photosynthetic rate could be used as an effective index in the selection of high yield soybean.
基金Supported by State Tobacco Monopoly Administration Project "National Survey of Pests in Tobacco" (110200902065)Yunnan Tobacco Monopoly Bureau Technology Project " Investigation of Tobacco Pests in Yunnan Province" (2010YN19)~~
文摘[Objective] The paper was to study the effect of tobacco blown spot on the yield and output value of tobacco leaf.[Method]The upper,middle and lower leaves in tobacco plant were selected during the harvest period of tobacco to carry out loss rate estimation of yield and output value of tobacco leaf caused by different disease levels of brown spot.Regression correlation analysis was also conducted.[Result]The disease levels of brown spot had extremely significant strong negative correlation with single leaf weight of tobacco leaf,and it had extremely significant strong positive correlation with the loss rate of single leaf weight.The increase speed of loss rate of single leaf weight of middle and upper leaves was obviously faster than that of lower leaves.The loss rates of single leaf weight of upper,middle and lower leaves were 3.18%-28.95%,3.43%-28.88% and 10.07%-26.90%,respectively.The higher the disease level of blown spot was,the lower the yield and output value of tobacco leaf was,and the corresponding loss rate was also higher.Correlation analysis showed that the disease level of blown spot had extremely significant strong negative correlation with the yield and output value of tobacco leaf,and it had extremely significant strong positive correlation with the loss rate of yield and output value.The negative impact of blown spot on the output value of tobacco leaf was far greater than that on the yield.The highest loss rate of the yield of tobacco leaf was 28.56%,while the highest loss rate of output value reached 89.67%.[Conclusion] The study provided theoretical basis for accurately holding the critical period for the control of blown spot,thus reducing the damage on tobacco leaf and improving the output value of tobacco leaf.
基金supported by the National Key R&D Program of China(2018YFD1000900)the National Natural Science Foundation of China(31571605,31801276)+5 种基金the Major Basic Research Project of Natural Science Foundation of Shandong Province,China(2018GHZ007)the Major Scientific and Technological Innovation Project in Shandong Province,China(2018YFJH0601)the Science and Technology Innovation Project of Shandong Academy of Agricultural Sciences,China(CXGC2018D04,CXGC2016B03-1)the Agricultural Scientific and Technological Innovation Project of Shandong Academy of Agricultural Sciences,China(CXGC2018E13,CXGC2016B10,CXGC2018F6)the Major Agricultural Application Technology Innovation Project in Shandong Province,China(201706)the earmarked fund for China Agriculture Research System(CARS-13)。
文摘Double-seed sowing(two seeds per hole)is the dominant pattern of peanut sowing in China,but within-hole plant competition usually limits their growth and yield formation.Besides,the traditional double-seed sowing method does not facilitate mechanization during sowing.The objective of this study was to determine if single-seed sowing at a proper seeding rate yielded better than traditional double-seed sowing pattern and the differences of physiological metabolism of roots.A field experiment was conducted in two consecutive years to compare pod yields of single-seed sowing at 180000(S180),225000(S225),and 270000 seeds ha^-1(S270)with that of double-seed sowing at 270000 seeds ha^-1(D270)using a completely randomized block design with four replications.And the root bleeding sap rate,nutrient content,and the main hormone contents in root bleeding sap were also comparatively investigated.Although the pod yields of single-seed sowing at the three densities were higher than that of traditional double-seed sowing(D270),S225 yielded better than the other two single-seed sowing treatments(S180 and S270).The increased pod yield in single-seed sowing at 225000 seeds ha^-1 was mainly due to the higher pod dry weight per plant and harvest index.The improved pod dry weight and shoot growth had closely relationship with the enhanced root physiological traits such as the increased root bleeding sap rate,content of free amino acids,soluble sugars,K^+,Mg^2+,Zn^2+,and Ca^2+of the individual plant root.The improved activity of root reductive,nitrate reductase(NR)and ATPase and higher zeatin and zeatin riboside(Z+ZR)content of root bleeding sap were alsocrucial to the pod and shoot growth of peanut.Single-seed sowing at a moderate seeding rate(S225)is a potential practice to increase pod yield and to save seed cost.
基金supported by the National Basic Research Program of China(973 Program,2010CB951502)the Special Fund for Agro-Scientific Research in the Public Interest in China(201103001)
文摘Excessive use of N fertilizer in intensive agriculture can increase crop yield and at the same time cause high carbon(C) emissions.This study was conducted to determine optimized N fertilizer application for high grain yield and lower C emissions in summer corn(Zea mays L.).A field experiment, including 0(N0), 75(N75), 150(N150), 225(N225), and 300(N300) kg N ha–1 treatments, was carried out during 2010–2012 in the North China Plain(NCP).The results showed that grain yield, input energy, greenhouse gas(GHG) emissions, and carbon footprint(CF) were all increased with the increase of N rate, except net energy yield(NEY).The treatment of N225 had the highest grain yield(10 364.7 kg ha–1) and NEY(6.8%), but the CF(0.25) was lower than that of N300, which indicates that a rate of 225 kg N ha–1 can be optimal for summer corn in NCP.Comparing GHG emision compontents, N fertilizer(0–51.1%) was the highest and followed by electricity for irrigation(19.73–49.35%).We conclude that optimazing N fertilizer application rate and reducing electricity for irrigation are the two key measures to increase crop yield, improve energy efficiency and decrease GHG emissions in corn production.
文摘Using cottonseed hull as the control substrate, different proportions of the untreated and treated Carya cathayensis Sarg shells were added to cultivation of Pleurotus geesteranus. The mycelial growth rate, yield, nutritional composition and contents of heavy metals of the Pleurotus geesteranus cultivated on these substrates were determined. The results suggest that added to treated Carya cathayensis Sarg shell promoted the mycelial growth and increased the yield, biological efficiency and the contents of crude fiber, ash, amino acids and essential amino acids of Pleurotus geesteranus. In addition, the fat content and soluble sugar contents of Pleurotus geesteranus were decreased with the increase of the Carya cathayensis Sarg shell content in substrate, but their contents of heavy metals including mercury (Hg), arsenic (As), cadmium (Cd) and lead (Pb) were higher than that obtained on control substrate.
基金This research was supported by the National Natural Sci—ence Foundation of China(Grant No.50474015)
文摘In Haigh Westergaard stress space linear combination of twin shear stress and Tresca yield functions is called the mean yield (MY) criterion. The mathematical relationship of the criterion and its plastic work rate done per unit volume were derived. A generalized worked example of slab forging was analyzed by the criterion and its corresponding plastic work rate done per unit volume. Then, the precision of the solution was compared with those by Mises and Twin shear stress yield criterions, respectively. It turned out that the calculated results by MY criterion were in good agreement with those by Mises criterion.
基金supported by grants from the National Natural Science Foundation of China(No.31301279)National Basic Research Program of China(No.2015CB150404)+1 种基金the National Key Technology R&D Program of China(No.2011BAD16B14)the Innovation Program of Heilongjiang Academy of Agricultural Sciences
文摘The objective of this study was to identify the response of grain yield to plant density and nitrogen rate in spring maize hybrids released from 1970 to 2010 and grown extensively in Northeast China.Twenty-one hybrids were grown for 2 years in Northeast China at densities of 30,000,52,500,75,000,and 97,500 plants ha^(-1)and N application levels of 0,150,300,and 450 kg N ha^(-1).Irrespective of density or nitrogen application rate,grain yields both per plant and per unit area were significantly higher for newer than older hybrids.As plant density increased from 30,000 to 97,500 plant ha^(-1),yield per plant of 1970 s,1980 s,1990 s,and 2000 s hybrids decreased by 50%,45%,46%,and 52%,respectively.The response of grain yield per unit area to plant density was curvilinear.The estimated optimum plant densities were about 58,000,49,000,65,000,and 65,000 plants ha^(-1)for hybrids released in the 1970 s,1980s,1990 s,and 2000 s,respectively.The theoretical optimum densities for the hybrids released from the 1970 s to the 2000 s increased by 1750 plants ha^(-1)decade^(-1).Nitrogen fertilization significantly increased grain yields per plant and per unit area for all hybrids.The theoretical optimum N application rates for high yield for hybrids released in the 1970 s and 1980 s were about 280 and 360 kg ha^(-1),and the hybrids from the 1990 s and 2000 s showed highest yield at 330 kg ha^(-1)N.No significant difference in the grain yields of 2000 s hybrids between the N levels of 150 to 450 kg ha^(-1)was found.Significant yield gains per plant and per unit area were found,with average increases of 17.9 g plant^(-1)decade^(-1)and936 kg ha^(-1)decade^(-1)over the period 1970–2010,respectively.Yield gains were attributed mainly to increased yield per plant,contributed by increases in kernel number per ear and1000-kernel weight.The rates of lodging and barren plants of newer hybrids were significantly lower than those of older ones,especially at high plant density.
基金Project(51074052)supported by the National Natural Science Foundation of ChinaProject(BK20140334)supported by the Basic Research Program of Jiangsu Province+2 种基金ChinaProject(14KJB460024)supported by the Natural Science Foundation of Jiangsu Higher Education Institutions of ChinaProject(2014M561707)supported by China Postdoctoral Science Foundation
文摘In order to overcome the nonlinearity of Mises criterion, a new linear yield criterion with a dodecagon shape of the same perimeter as Mises criterion was derived by means of geometrical analysis. Its specific plastic work rate expressed as a linear function of the yield stress, the maximum and minimum strains was also deduced and compared with that of Mises criterion. The physical meaning of the proposed yield criterion is that yielding of materials begins when the shear yield stress τs reaches the magnitude of 0.594σs. By introducing the Lode parameter, validation of evolution expressions of the proposed yield criterion with those based on Tresca, Mises and TSS criteria as well as available classical yield experimental results of various metals shows that the present results intersect with Mises results and coincide well with experimental data. Moreover, further application to the limit analysis of circle plate as an example is performed to demonstrate the effectiveness of the proposed yield criterion, and the subsequent comparison of limit loads with the Tresca analytical solutions and Mises numerical results shows that the present results are higher than the Tresca analytical results, and are in good agreement with the Mises numerical results.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11332010,51271174 and 51571013the Fundamental Research Funds for the Central Universities
文摘The mechanism of the critical strain of serrated yielding is studied via tension tests at various strain rates. Betore the critical strain, it is deduced that dislocations are not pinned at high strain rates, and dislocations at low strain rates are pinned but cannot escape. The critical strain depends on the first pinning process at high strain rates and on the first unpinning process at low strain rates. The calculated results based on the two criteria are in good consistency with the experiment.
基金Supported by International Cooperation Project of China's Agricultural Insurance (DelPHE ACIC)
文摘Based on theoretical analysis of crop risk and premium rate setting,we take the case of premium rate setting of insurance on cotton yield in Shache County,Shaya County and Aksu City of Xinjiang.Using parametric methods and insurance actuarial technique,we select the optimal model for risk fitting of cotton yield in three areas;compare the premium rate calculated accurately under four risk distribution assumptions of cotton yield,and the rational premium rate,to analyze the impact of risk distribution of crop yield on premium rate setting.The empirical results show that the Logistic distribution is the optimal distribution for risk fitting of cotton yield in three areas;the rational net premium rate of cotton insurance in three areas is 7.62%,6.32% and 4.96%,respectively;there are errors in premium rate setting under assumptions of normal distribution,normalized skew distribution and Weibull distribution,ranging from 0.2 percentage points to 8 percentage points.Thus,it indicates that the selection of risk distribution model of yield directly affects the accuracy of premium rate setting of crops,and the key to accurate premium rate setting of crops lies in correct selection of risk distribution model of yield.
基金Supported by Liaoning Innovation Team Project of Peanut Industry of National Modern Agricultural Industry Technology System(2016007022)
文摘The effects of calcium application rate on dry matter accumulation and yield of peanut were studied under high-yielding field condition. The variety used for the study was Tang A8252( Spanish peanut). The results showed that number of full fruit,dry weight per plant,kernel yield,and pod yield all increased with calcium application increased,and they decreased when calcium application rate was more than150 kg/ha. Both the height of main stem and the length of side shoot decreased with calcium application increased. Therefore,to obtain the optimal agronomic character index and the highest yield benefit,the suggested calcium application rate would be 150 kg/ha for peanut.
基金supported by the earmarked fund for China Agriculture Research System (CARS-0301-24)the National Natural Science Foundation of China (31771727)+5 种基金the National Key Technology R&D Program of China (2015BAD23B04-2)The research project was also supported by the Shanxi Scholarship Council,China (2015Key 4)the Shanxi Science and Technology Innovation Team Project,China (201605D131041)the Jinzhong Science and Technology Plan Project,China (Y172007-2)the Sanjin Scholar Support Special Funds,Chinathe Special Fund for Agro-scientific Research in the Public Interest,China (201503120)
文摘Sowing date and seeding rate are critical for productivity of winter wheat(Triticum aestivum L.).A three-year field experiment was conducted with three sowing dates(20 September(SD1),1 October(SD2),and 10 October(SD3)) and three seeding rates(SR67.5,SR90,and SR112.5) to determine suitable sowing date and seeding rate for high wheat yield.A large seasonal variation in accumulated temperature from sowing to winter dormancy was observed among three growing seasons.Suitable sowing dates for strong seedlings before winter varied with the seasons,that was SD2 in 2012–2013,SD3 in 2013–2014,and SD2 as well as SD1 in 2014–2015.Seasonal variation in precipitation during summer fallow also had substantial effects on soil water storage,and consequently influenced grain yield through soil water consumption from winter dormancy to maturity stages.Lower consumption of soil water from winter dormancy to booting stages could make more water available for productive growth from anthesis to maturity stages,leading to higher grain yield.SD2 combined with SR90 had the lowest soil water consumption from winter dormancy to booting stages in 2012–2013 and 2014–2015; while in 2013–2014,it was close to that with SR67.5 or SR112.5.For productive growth from anthesis to maturity stages,SD2 with SR90 had the highest soil water consumption in all three seasons.The highest water consumption in the productive growth period resulted in the best grain yield in both low and high rainfall years.Ear number largely contributed to the seasonal variation in grain yield,while grain number per ear and 1 000-grain weight also contributed to grain yield,especially when soil water storage was high.Our results indicate that sowing date and seeding rate affect grain yield through seedling development before winter and also affect soil water consumption in different growth periods.By selecting the suitable sowing date(1 October) in combination with the proper seeding rate of 90 kg ha–1,the best yield was achieved.Based on these results,we recommend that the current sowing date be delayed from 22 or 23 September to 1 October.
基金Project(10502025) supported by the National Natural Science Foundation of ChinaProject(101005) supported by Fok Ying Tong Education FoundationProject(BK2007528) supported by the Natural Science Foundation of Jiangsu Province,China
文摘To understand the high strain rate deformation mechanism and determine the grain size,strain rate and porosity dependent yield strength of nanocrystalline materials,a new mechanical model based on the deformation mechanism of nanocrystalline materials under high strain rate loading was developed.As a first step of the research,the yield behavior of the nanocrystalline materials under high strain rate loading was mainly concerned in the model and uniform deformation was assumed for simplification.Nanocrystalline materials were treated as composites consisting of grain interior phase and grain boundary phase,and grain interior and grain boundary deformation mechanisms under high strain rate loading were analyzed,then Voigt model was applied to coupling grain boundary constitutive relation with mechanical model for grain interior phase to describe the overall yield mechanical behavior of nanocrystalline materials.The predictions by the developed model on the yield strength of nanocrysatlline materials at high strain rates show good agreements with various experimental data.Further discussion was presented for calculation results and relative experimental observations.
基金supported by the Ministry of Agriculture of China(Grant No.2005-2009)
文摘The nitrogen uptake, yield and its components for two super-high-yielding hybrid rice combinations, Guodao 6 and Eryou 7954 were investigated under different plant densities (15, 18, and 21 plants/m^2) and different nitrogen application rates (120, 150, 180, and 210 kg/hm^2). The experiment was conducted on loam soil during 2004-2006 at the experimental farm of the China National Rice Research Institute in Hangzhou, China. In these years, the two hybrid rice cleady showed higher yield at a plant density of 15 plants/m^2 with a nitrogen application rate of 180 kg/hm^2. Guodao 6 produced an average grain yield of 10 215.6 kg/hm^2 across the three years, while the yield of Eryou 7954 was 9 633.0 kg/hm^2. With fewer plants per unit-area and larger plants in the plots, the two hybrid rice produced more panicles per plant in three years. The highest nitrogen uptake of the two hybrid rice was at a plant density of 15 plants/m^2 with a nitrogen application rate of 180 kg/hm^2. Further increasing nitrogen application rate was not advantageous for nitrogen uptake in super-high-yielding rice under the same plant density.