期刊文献+
共找到3,239篇文章
< 1 2 162 >
每页显示 20 50 100
Magnesium fertilizer application increases peanut growth and pod yield under reduced nitrogen application in southern China
1
作者 Yu Gao Ruier Zeng +6 位作者 Suzhe Yao Ying Wang Jianguo Wang Shubo Wan Wei Hu Tingting Chen Lei Zhang 《The Crop Journal》 SCIE CSCD 2024年第3期915-926,共12页
This study investigated the effect of magnesium application on peanut growth and yield under two nitrogen(N)application rates in acidic soil in southern China.The chlorophyll content,net photosynthetic rate and dry ma... This study investigated the effect of magnesium application on peanut growth and yield under two nitrogen(N)application rates in acidic soil in southern China.The chlorophyll content,net photosynthetic rate and dry matter accumulation of the N-sensitive cultivar decreased under reduced N treatments,whereas no effect was observed on the relevant indicators in the N-insensitive variety GH1026.Mg application increased the net photosynthetic rate by increasing the expression of genes involved in chlorophyll synthesis and Rubisco activity in the leaves during the pegging stage under 50%N treatment,while no effect on the net photosynthetic rate was observed under the 100%N treatment.The rate of dry matter accumulation at the early growth stage,total dry matter accumulation and pod yield at harvest increased after Mg application under 50%N treatment by increasing the transportation of assimilates from stems and leaves to pods in both peanut varieties,whereas no effect was found under 100%N treatment.Moreover,Mg application increased the NUE under 50%N treatment.No improvement of NUE in either peanut variety was found under 100%N treatment,while Mg application under the 50%N treatment can obtain a higher economic benefit than the 100%N treatment.In acidic soil,application of 307.5 kg ha^(-1)of Mg sulfate fertilizer under 50%reduced nitrogen application is a suitable fertilizer management measure for improving carbon assimilation,NUE and achieve high peanut yields in southern China. 展开更多
关键词 PEANUT Magnesium YIELD Reduced nitrogen application rate
下载PDF
Effects of phosphorus fertilizer application rate on transformation processes of phosphorus fractions in the purple alluvial soil of a riparian zone 被引量:1
2
作者 HE Li-ping JIA Kai-tao +3 位作者 LIU Dan WANG Ke-hong DUAN Lin-Yan LIN Jun-jie 《Journal of Mountain Science》 SCIE CSCD 2023年第6期1561-1574,共14页
Effects of phosphorus(P)fertilizer application rate on soil transformation processes of P fraction are still unclear in the riparian zone.Purple alluvial soils in the riparian zone of the Three Gorges Reservoir were c... Effects of phosphorus(P)fertilizer application rate on soil transformation processes of P fraction are still unclear in the riparian zone.Purple alluvial soils in the riparian zone of the Three Gorges Reservoir were collected to conduct a 21-day incubation executed by two hydrological environments(drying and flooding)and ten application rates of P fertilizer.Transformation percentages of P fertilizer(TPPF)were calculated as content differences of soil P fractions between fertilizer addition and none fertilizer addition divided by soil total P increases caused by fertilizer addition.TPPF to inorganic P extracted by sodium hydroxide(NaOH-Pi)and hydrochloric acid(HCl-Pi)increase by 20.91%(9.71%)and 24.26%(40.72%)under the drying(flooding)environment.Instead,TPPF to the other fractions decrease.Phosphorus fertilizer input mainly has indirect positive and negative effects on organic P via precipitated P under the drying and flooding environments and finally has indirect positive effects on labile P(p<0.001).Percentage changes of water-soluble inorganic P(H2O-Pi)and HCl-Pi under the flooding environment are higher than that under the drying environment,and percentage changes of organic P extracted by sodium hydrogen carbonate(Na HCO3-Po)and NaOH-Pi show an opposite trend(p<0.01).?(differences in soil P fraction content between flooding and drying incubations)H2O-Pi is negatively correlated with?NaHCO3-Po,and?NaHCO3-Po is positively correlated with?NaOH-Pi(p<0.001).In conclusion,P fertilizer is transformed more into precipitated P than into other P fractions with an application rate increase.Phosphorus fertilizer input mainly increases organic P via precipitated P under the drying environment and decreases organic P via precipitated P under the flooding environment,and organic P is further transformed into labile P.With P fertilizer input,P release caused by flooding is derived from NaHCO3-Po release triggered by NaOH-Pi release.The results can be helpful for the understanding of P fertilizer migration processes from the riparian zone soil to the Three Gorges Reservoir under rain leaching and flooding. 展开更多
关键词 Hedley fractionation Phosphorus fraction Hydrological environments Three Gorges Reservoir application rate Riparian zone
下载PDF
Differing responses of root morphology and physiology to nitrogen application rates and their relationships with grain yield in rice 被引量:2
3
作者 Kun Liu Yun Chen +6 位作者 Siyu Li Weilu Wang Weiyang Zhang Hao Zhang Junfei Gu Jianchang Yang Lijun Liu 《The Crop Journal》 SCIE CSCD 2023年第2期618-627,共10页
Root morphology and physiology influence aboveground growth and yield formation in rice.However,root morphological and physiological differences among rice varieties with differing nitrogen(N)sensitivities and their r... Root morphology and physiology influence aboveground growth and yield formation in rice.However,root morphological and physiological differences among rice varieties with differing nitrogen(N)sensitivities and their relationship with grain yield are still unclear.In this study,rice varieties differing in N sensitivity over many years of experiments were used.A field experiment with multiple N rates(0,90,180,270,and 360 kg ha^(-1))was conducted to elucidate the effects of N application on root morphology,root physiology,and grain yield.A pot experiment with root excision and exogenous application of 6-benzyladenine(6-BA)at heading stage was used to further verify the above effects.The findings revealed that(1)under the same N application rate,N-insensitive varieties(NIV)had relatively large root biomass(root dry weight,length,and number).Grain yield was associated with root biomass in NIV.The oxidation activity and zeatin(Z)+zeatin riboside(ZR)contents in roots obviously and positively correlated with grain yield in N-sensitive varieties(NSV),and accounted for its higher grain yield than that of NIV at lower N application rates(90 and 180 kg ha^(-1)).(2)The root dry weight required for equal grain yield of NIV was greater than that of NSV.Excision of 1/10 and 1/8 of roots at heading stage had no discernible effect on the yield of Liangyoupeijiu(NIV),and it significantly reduced yield by 11.5%and 21.3%in Tianyouhuazhan(NSV),respectively,compared to the treatment without root excision.The decrease of filled kernels and grain weight after root excision was the primary cause for the yield reduction.Root excision and exogenous 6-BA application after root excision had little influence on the root activity of NIV.The oxidation activity and Z+ZR contents in roots of NSV decreased under root excision,and the increase in the proportion of excised roots aggravated these effects.The application of exogenous 6-BA increased the root activity of NSV and increased filled kernels and grain weight,thereby reducing yield loss after root excision.Thus,the root biomass of NIV was large,and there may be a phenomenon of"root growth redundancy."Vigorous root activity was an essential feature of NSV.Selecting rice varieties with high root activity or increasing root activity by cultivation measures could lead to higher grain yield under lower N application rates. 展开更多
关键词 Rice(Oryza sativa L.)varieties Nitrogen(N)application rate Grain yield Root morphology and physiology N sensitivities
下载PDF
Effects of the potassium application rate on lipid synthesis and eating quality of two rice cultivars 被引量:1
4
作者 CHEN Guang-yi PENG Li-gong +7 位作者 LI Cong-mei TU Yun-biao LAN Yan WU Chao-yue DUAN Qiang ZHANG Qiu-qiu YANG Hong LI Tian 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第7期2025-2040,共16页
Lipid content has an important effect on rice eating quality,but the effects of fertilizer application rate on the lipid synthesis and eating quality of rice are not well understood.Potassium(K)has a strong influence ... Lipid content has an important effect on rice eating quality,but the effects of fertilizer application rate on the lipid synthesis and eating quality of rice are not well understood.Potassium(K)has a strong influence on rice quality and the requirement for K fertilizer in rice is greater than for nitrogen(N)and phosphorus(P)fertilizers.To investigate the effects of K fertilizer on the lipid synthesis and eating quality of rice,we used Nanjing 9108(NJ9108,japonica)and IR72(indica)rice as experimental materials and four K levels:K0(0 kg ha^(-1)),K1(90 kg ha^(-1)),K2(135 kg ha^(-1))and K3(180 kg ha^(-1)).The results showed that the lipid content,free fatty acid(FFA)content,unsaturated fatty acid(UFA)content,malonyl-CoA(MCA)content,phosphatidic acid(PA)content,lipid synthesis-related enzyme activities and eating quality first increased and then decreased with increasing K in both cultivars.The maximum values were obtained under K2.However,the saturated fatty acid(SFA)content showed the opposite trend.No significant differences were found in pyruvate(PYR)content among the K treatments.The protein and oxaloacetic acid(OAA)contents and phosphoenolpyruvate carboxylase(PEPCase)activity of NJ9108 first decreased and then increased with increasing K,and the minimum values were obtained under K2;while IR72 showed the opposite trend and the maximum values were obtained under K1.Overall,increasing K optimized the fatty acid components and increased the lipid content and eating quality of rice by enhancing lipid synthesis-related enzyme activities and regulating substrate competition for lipid and protein synthesis.The optimal K application rate for lipid synthesis,eating quality and grain yield was 135 kg ha^(-1)for both cultivars. 展开更多
关键词 RICE potassium application rate lipid content lipid synthesis-related enzyme fatty acid components eating quality
下载PDF
Optimum Application Rate of Nitrogen in Summer Peanut in Southern Shandong Area
5
作者 Hongjie TANG 《Asian Agricultural Research》 2023年第3期34-36,共3页
[Objectives]To study the effect of nitrogen(N)on the growth demand of summer peanuts under a certain level of phosphorus and potassium fertilizers,and to carry out experiments on nitrogen fertilizer control of summer ... [Objectives]To study the effect of nitrogen(N)on the growth demand of summer peanuts under a certain level of phosphorus and potassium fertilizers,and to carry out experiments on nitrogen fertilizer control of summer peanuts.[Methods]Four treatments were set up in the experiment:no-nitrogen plot(N 0P_(4)K_(4)),optimized nitrogen plot(N_(7)P_(4)K_(4)),70%optimized nitrogen plot(N_(5)P_(4)K_(4)),130%optimized nitrogen plot(N 9P 4K 4),repeated 3 times,and arranged in random blocks.The area of the plot was 42 m^(2),ridges were set between the plots,and protective rows of more than 1 m were set around the experimental site.The types of fertilizers were urea,superphosphate,and imported potassium chloride,and the variety of peanuts was Linhua 5.Except for the level of fertilization,other agricultural operations were the same,and soil sampling tests,field records,and yield testing were carried out according to the requirements of the plan.[Results]On the basis of 60 kg/ha of phosphorus and potassium fertilizer application,the optimum economical fertilizer application rate and the highest application rate of pure nitrogen were about 115.20 and 131.25 kg/ha,respectively.[Conclusions]This study is expected to provide a certain basis for the high-quality and high-yield summer peanuts in southern Shandong area. 展开更多
关键词 Southern Shandong area Summer peanut Nitrogen fertilizer Optimum application rate
下载PDF
Effects of Nitrogen Application Rate, Density and Seedling Age on Dry Matter Accumulation of No-tillage Rape in Seedling Stage 被引量:5
6
作者 艾复清 张帆 +1 位作者 舒中兵 樊宁 《Agricultural Science & Technology》 CAS 2008年第6期93-96,107,共5页
[Objective] The aim of the research was to find the optimal nitrogen application rate, density and seedling age for no-tillage rape in seedling stage. [Method] With the D-optimal quadratic regression design for three ... [Objective] The aim of the research was to find the optimal nitrogen application rate, density and seedling age for no-tillage rape in seedling stage. [Method] With the D-optimal quadratic regression design for three factors, the 310 scheme was designed to study the effects of nitrogen application rate, density and seedling age on dry matter accumulation of no-tillage rape in seedling stage. [Result] With the increase of nitrogen application rate, density and seedling age, the dry matter content appeared like a parabola, increasing firstly and then declining. The change of nitrogen application rate caused greater influence than that of density and seedling age; the interaction effects between nitrogen application rate and density were greater than that between nitrogen application rate and seedling age as well as between density and seedling age. [Conclusion] Considered comprehensively, the dry matter content of no-tillage rape in seedling stage reached the highest level (4 768.2 kg/hm2) when the nitrogen application rate, the density and the seedling age were 195 kg/hm2, 93 000 plants/hm2 and 33 d, respectively. 展开更多
关键词 Nitrogen application rate DENSITY SEEDLING age Dry matter ACCUMULATION SEEDLING NO-TILLAGE RAPE
下载PDF
Soil enzymatic activities and microbial community structure with different application rates of Cd and Pb 被引量:29
7
作者 KHAN Sardar CAO Qing +2 位作者 HESHAM Abd El-Latif XIA Yue HE Ji-zheng 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第7期834-840,共7页
This study focused on the changes of soil microbial diversity and potential inhibitory effects of heavy metals on soil enzymatic activities at different application rates of Cd and/or Pb. The soil used for experiments... This study focused on the changes of soil microbial diversity and potential inhibitory effects of heavy metals on soil enzymatic activities at different application rates of Cd and/or Pb. The soil used for experiments was collected from Beijing and classified as endoaquepts. Pots containing 500 g of the soil with different Cd and/or Pb application rates were incubated for a period of 0, 2, 9, 12 weeks in a glasshouse and the soil samples were analyzed for individual enzymes, including catalase, alkaline phosphatase and dehydrogenase, and the changes of microbial community structure. Results showed that heavy metals slightly inhibited the enzymatic activities in all the samples spiked with heavy metals. The extent of inhibition increased significantly with increasing level of heavy metals, and varied with the incubation periods. The soil bacterial community structure, as determined by polymerase chain reaction- denaturing gradient gel electrophoresis techniques, was different in the contaminated samples as compared to the control. The highest community change was observed in the samples amended with high level of Cd. Positive correlations were observed among the three enzymatic activities, but negative correlations were found between the amounts of the heavy metals and the enzymatic activities. 展开更多
关键词 soil contamination heavy metals application rate enzymatic activity microbial community
下载PDF
Effects of Plant Density and Nitrogen Application Rate on Grain Yield and Nitrogen Uptake of Super Hybrid Rice 被引量:12
8
作者 LIN Xian-qing ZHU De-feng CHEN Hui-zhe ZHANG Yu-ping 《Rice science》 SCIE 2009年第2期138-142,共5页
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
关键词 super-high-yielding cultivation hybrid rice grain yield nitrogen uptake plant density nitrogen application rate
下载PDF
Effects of Different Nitrogen Application Rates and Methods on Root Nodule Growth and Yield of Soybean 被引量:5
9
作者 JI Yue-mei LUO Rui-ping +1 位作者 ZHAO Zhi-gang LIAN Jin-pan 《Agricultural Science & Technology》 CAS 2018年第2期67-72,共6页
This study was conducted wiffl a spring soybean variety Jindou 19 to test file effects of rhizobia inoculation or non-inoculation and nitrogen application rates at 0, 27, 54 and 75 kg/hm^2 (N1-4) on root nodule dry ... This study was conducted wiffl a spring soybean variety Jindou 19 to test file effects of rhizobia inoculation or non-inoculation and nitrogen application rates at 0, 27, 54 and 75 kg/hm^2 (N1-4) on root nodule dry weight, root nodule number, yield and yield components of soybean. The results showed that the nitrogen fertilizer significantly affected soybean root noduce and soybean yield, the dry weight and number of root nodules increased gradually with the increase of nitrogen application rate, and the yield of file rhizobia inoculated treatment was significantly higher than that of file rhizobia non-inoculated treatment; and under file condition of file rhizobia inoculation, with nitrogen application amount at 75 kg/hm^2, file Jindou 19 performed a better nitrogen fixing effect in file growing stage, and its plot yield was 4 997.417 kg/hm^2, 4.06% higher than that of file treatment without inoculating rhizobium and 12.50% higher than that of the treatment without applying nitrogen fertilizer. 展开更多
关键词 SOYBEAN RHIZOBIUM Nitrogen application rate YIELD
下载PDF
Determination of optimum nitrogen application rates in Zhejiang Province, China, based on rice yields and ecological security 被引量:6
10
作者 LI Yan CHEN Yi +2 位作者 WU Chun-yan TANG Xu JI Xiao-jiang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2015年第12期2426-2433,共8页
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
关键词 optimum nitrogen application rate Zhejiang rice yields ecological security
下载PDF
Yield performance and optimal nitrogen and phosphorus application rates in wheat and faba bean intercropping 被引量:2
11
作者 XIAO Jing-xiu ZHU Ying-an +3 位作者 BAI Wen-lian LIU Zhen-yang TANG Li ZHENG Yi 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2021年第11期3012-3025,共14页
Yield performance in cereal and legume intercropping is related to nutrient management,however,the yield response of companion crops to nitrogen(N)input is inconclusive and only limited efforts have focused on ratione... Yield performance in cereal and legume intercropping is related to nutrient management,however,the yield response of companion crops to nitrogen(N)input is inconclusive and only limited efforts have focused on rationed phosphorous(P)fertilization.In this study,two multi-year field experiments were implemented from 2014-2019 under identical conditions.Two factors in a randomized complete block design were adopted in both experiments.In field experiment 1,the two factors included three planting patterns(mono-cropped wheat(MW),mono-cropped faba bean(MF),and wheat and faba bean intercropping(W//F))and four N application rates(N0,0 kg N ha^(-1);N1,90 and 45 kg N ha^(-1) for wheat and faba beans,respectively;N2,180 and 90 kg N ha^(-1) for wheat and faba beans,respectively;and N3,270 and 135 kg N ha^(-1) for wheat and faba beans,respectively).In field experiment 2,the two factors included three P application rates(P0,0 kg P_(2)O_(5) ha^(-1);P1,45 kg P_(2)O_(5) ha^(-1);and P2,90 kg P_(2)O_(5) ha^(-1))and the same three planting patterns(MW,MF,and W//F).The yield performances of inter-and mono-cropped wheat and faba beans under different N and P application rates were analyzed and the optimal N and P rates for intercropped wheat(IW)and MW were estimated.The results revealed that intercropping favored wheat yield and was adverse to faba bean yield.Wheat yield increased by 18-26%,but faba bean yield decreased by 5-21% in W//F compared to MW and MF,respectively.The stimulated IW yield drove the yield advantage in W//F with an average land equivalent ratio(LER)of 1.12.N and P fertilization benefited IW yield,but reduced intercropped faba bean(IF)yield.Nevertheless,the partial LER of wheat(pLER_(wheat))decreased with increasing N application rates,and the partial LER of faba bean(pLER_(faba bean))decreased with increasing P application rates.Thus,LER decreased as N input increased and tended to decline as P rates increased.IW maintained a similar yield as MW,even under reduced 40-50% N fertilizer and 30-40% P fertilizer conditions.The estimated optimum N application rates for IW and MW were 150 and 168 kg ha^(-1),respectively,and 63 and 62 kg ha^(-1) for P_(2)O_(5),respectively.In conclusion,W//F exhibited yield advantages due to stimulated IW yield,but the intercropping yield benefit decreased as N and P inputs increased.Thus,it was concluded that modulated N and P rates could maximize the economic and ecological functions of intercropping.Based on the results,rates of 150 kg N ha^(-1) and 60 kg P_(2)O_(5) ha^(-1) are recommended for IW production in southwestern China and places with similar conditions. 展开更多
关键词 land equivalent ratio nitrogen and phosphorus optimal application rate wheat and faba bean intercropping yield performance
下载PDF
Effects of Calcium Application Rate on Dry Matter Accumulation and Yield of Peanut 被引量:1
12
作者 Junjie XIU Xueliang LIU 《Asian Agricultural Research》 2018年第5期79-81,共3页
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
关键词 PEANUT Calcium application rate Dry matter accumulation YIELD
下载PDF
Effects of Density and Nitrogen Application Rate on Population Structure and Yield of Early-maturing Late Japonica Tongjing 981 被引量:1
13
作者 Genyou ZHOU Bo WANG Hua XIA 《Agricultural Biotechnology》 CAS 2020年第4期92-98,150,共8页
The study adopted split block design with different treatment levels of density and fertilizer to investigate the growth period,population tiller dynamics,leaf area,dry matter accumulation,plant traits,panicle-grain s... The study adopted split block design with different treatment levels of density and fertilizer to investigate the growth period,population tiller dynamics,leaf area,dry matter accumulation,plant traits,panicle-grain structure,yielding ability and stress resistance of Tongjing 981 under different density and nitrogen fertilizer levels,so as to make clear the effects of different densities and nitrogen fertilizer levels on the population development and yield of Tongjing 981.The results showed that a too-low density was not conductive to the formation of sufficient number of panicles,and when the density was too high,it affected the number of grains per panicle and 1000-grain weight;and when nitrogen fertilizer was at a too-low level,it would restrict the population development,and a too-high nitrogen fertilizer easily led to the extension of the growth period and the aggravation of sheath blight.Reasonable density and fertilization level could make the development of individuals in Tongjing 981 population coordinated,and further help to establish a reasonable population structure,maintain a high leaf area and dry matter accumulation during the filling period,and balance the relationship of population dry matter weight with economic coefficient and panicle,grain and weight,thereby improving the population quality and yield of Tongjing 981. 展开更多
关键词 Tongjing 981 DENSITY Nitrogen application rate YIELD
下载PDF
Effects of application date and rate of foliar-applied glyphosate on pine seedlings in Turkey
14
作者 Mehmet Can Cap Derya Essn 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第3期583-591,共9页
Glyphosate is the herbicide most extensively used for site preparation and conifer release. It is a broadspectrum herbicide and therefore crop safety is a critical issue. This study assessed the early effects of 14 di... Glyphosate is the herbicide most extensively used for site preparation and conifer release. It is a broadspectrum herbicide and therefore crop safety is a critical issue. This study assessed the early effects of 14 different treatments, including no weed control, manual weed control, and 12 foliar-applied herbicide treatments at low,intermediate, high, and highest application rates and application timing on glyphosate phytotoxicity of containerized seedlings of Austrian pine(Pinus nigra J.F.Arnold.), Scots pine(P. sylvestris L.) and maritime pine(P.pinaster Aiton), conifer species widely used for afforestation and supplementary plantings in Turkish forestry. In general, Scots pine seedlings were tolerant to glyphosate compared to the other species. Glyphosate phytotoxicity varied significantly according to the time and rate of application. Seedlings were relatively tolerant to glyphosate in April whereas they were intolerant in May. The highest herbicide rate(1.2% v:v) was consistently phytotoxic to all species. Moreover, the effect of herbicide rate on seedling survival and growth varied significantly according to application date(i.e., application rate 9 date interaction). Seedlings appeared tolerant to glyphosate at low and intermediate rates(0.2, 0.4% v:v) between midspring and mid-summer, whereas they demonstrated significant sensitivity to the highest rate across all time periods. Glyphosate at the high rate(0.8% v:v) was particularly more phytotoxic when applied in May. Application of glyphosate at rates up to 0.8% could be recommended for weed control without significant pine damage in midspring when the needles presumably have a dense leaf epicuticular wax layer limiting herbicide penetration.Applications of 0.8 and 1.2% v:v are not recommended during May–June. 展开更多
关键词 application date and rate Glyphosate screening PINES Seedling tolerance
下载PDF
Effects of N Application Rates and NO_3-N to NH_4-N Ratios on Yield and Quality of Flue-cured Tobacco Planted in Black Soil
15
作者 SHAN Dexin GUAN Shengyu SHAN Dechen XU Jinggang 《Journal of Northeast Agricultural University(English Edition)》 CAS 2006年第2期121-124,共4页
A field experiment about effects of nitrogen application rates and different NO3-N to NH4-N ratios on agronomic, chemical and biological characteristics as well as yield and quality of flue-cured tobacco grown in a bl... A field experiment about effects of nitrogen application rates and different NO3-N to NH4-N ratios on agronomic, chemical and biological characteristics as well as yield and quality of flue-cured tobacco grown in a black soil was conducted from 2004 to 2005 in Heilongjiang Province. The results showed that the nitrogen application rates at 45 kg·hm^-2 with the ratio of 75% NO3-N to 25% NH4-N resulted in the highest potassium and reducing sugar contents in the flue-cured tobacco leaving with the highest quality grade and value. It is recommended that this ni- trogen application rate and NO3-N to NH4-N ratio should be widely applied on flue-cured tobacco grown in the black soil in Heilongjiang Province. 展开更多
关键词 N application rate NO3-N to NH4-N ratio flue-cured tobacco black soil
下载PDF
Deduction of plastic work rate per unit volume for unified yield criterion and its application 被引量:2
16
作者 赵德文 李婧 +1 位作者 刘相华 王国栋 《中国有色金属学会会刊:英文版》 CSCD 2009年第3期657-660,共4页
A unified linear expression of plastic work rate per unit volume is deduced from the unified linear yield criterion and the associated flow rule. The expression is suitable for various linear yield loci in the error t... A unified linear expression of plastic work rate per unit volume is deduced from the unified linear yield criterion and the associated flow rule. The expression is suitable for various linear yield loci in the error triangle between Tresca’s and twin shear stress yield loci on the π-plane. It exhibits generalization in which the different value of criterion parameter b corresponds to a specific linear formula of plastic work rate per unit volume. Finally, with the unified linear expression of plastic work rate and upper-bound parallel velocity field the strip forging without bulge is successfully analyzed and an analytical result is also obtained. The comparison with traditional solutions shows that when b=1/(1+ 3 ) the result is the same as the upper bound result by Mises’ yield criterion, and it also is identical to that by slab method with m=1, σ0=0. 展开更多
关键词 统一屈服准则 工作单位 塑料 体积 线性屈服准则 应用 屈服轨迹 流动法则
下载PDF
Phosphate Distribution and Movement in Soil-Root In-terface Zone: II. The Infinence of Soil Water Contentand Application Rates of Phosphate
17
作者 XUMING-GANG ZHANGYI-PING 《Pedosphere》 SCIE CAS CSCD 1995年第3期267-274,共8页
The phosphate in the soil-root interface zone under various soil water contents and application rates ofphosphate was still of depletion distribution which could be described by a power function in the form ofC/Co= ax... The phosphate in the soil-root interface zone under various soil water contents and application rates ofphosphate was still of depletion distribution which could be described by a power function in the form ofC/Co= ax ̄b(C/Co is the relative content of fertilized phosphate in a distance from the root surface x, a andb are the regression constants). The depletion rate of phosphate in soil near the root surface was higher andthe depletion range was narrower under lower soil moisture. On the contrary, at higher soil water content thedepletion range was wider, generally The application rate of phosphate led to the greater depletion intensityof phosphorus was higher in the heavier texture soils. In general, the depletion intensity in the soils, whichdecreased with increasing clay content or increa.sing buffering power of soil, decreased in the order as loessalsoil and black fou soil> lou soil> yellow cinnamon soil when 50 or 100 mg of phosphorus were applied in theform of KH_2PO_4. This result indicated that the phosphate distribution and its movement in the soil-rootinterface zone closely related with the buffering capacity of soil. 展开更多
关键词 application rate of phosphate phosphate distribution soil-root interface zone soil watercontent
下载PDF
Lithium manganese spinel materials for high-rate electrochemical applications 被引量:1
18
作者 Anna V.Potapenko Sviatoslav A.Kirillov 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2014年第5期543-543,544-558,共16页
In order to successively compete with supercapacitors, an ability of fast discharge is a must for lithium-ion batteries. From this point of view, stoichiometric and substituted lithium manganese spinels as cathode mat... In order to successively compete with supercapacitors, an ability of fast discharge is a must for lithium-ion batteries. From this point of view, stoichiometric and substituted lithium manganese spinels as cathode materials are one of the most prospective candidates, especially in their nanosized form. In this article, an overview of the most recent data regarding physico-chemical and electrochemical properties of lithium manganese spinels, especially, LiMn2O4 and LiNi0.5Mn1.5O4, synthesized by means of various methods is presented, with special emphasis of their use in high-rate electrochemical applications. In particular, specific capacities and rate capabilities of spinel materials are analyzed. It is suggested that reduced specific capacity is determined primarily by the aggregation of material particles, whereas good high-rate capability is governed not only by the size of crystallites but also by the perfectness of crystals. The most technologically advantageous solutions are described, existing gaps in the knowledge of spinel materials are outlined, and the ways of their filling are suggested, in a hope to be helpful in keeping lithium batteries afloat in the struggle for a worthy place among electrochemical energy systems of the 21st century. 展开更多
关键词 lithium-ion batteries high-rate applications cathode materials SPINELS
下载PDF
Effects of Nitrogen Application Rate and Seeding Density on Plant Growth and Seed Yield of Direct-seeding Rape
19
作者 Tengfang LAN Youyuan WANG +3 位作者 Mingxiang ZHU Lu XIONG Yin HAN Shuo XIAO 《Agricultural Biotechnology》 CAS 2018年第4期153-156,共4页
[Objectives] This study was conducted to explore the effects of different N application rates and densities on the growth and development of direct-seeding rape as well as on its yield.[Methods] A field experiment was... [Objectives] This study was conducted to explore the effects of different N application rates and densities on the growth and development of direct-seeding rape as well as on its yield.[Methods] A field experiment was carried out by setting five N fertilizer treatments and three density levels.[Results] Increasing seeding density and N application rate could improve the seed yield of rape. The suitable N application rate for the three densities were calculated using the fitted fertilizer efficiency models, respectively, to be 186.77, 221.35 and 236.14 kg/hm^2, at which the yields were the highest. The results showed that in this area, the seeding density of direct-seeding rape could be selected in the range of 6.0×10^5-7.5×10^5 plants/hm^2, and the suitable N application rate could be in the range of 221.35-236.14 kg/hm^2.[Conclusions] This study provides a theoretical basis for the maximization of spatial resource and efficient utilization of fertilizer. 展开更多
关键词 N application rate Seeding density Direct-seeding rape Fertilizer response model
下载PDF
Degradation Rate Assessment of Biodegradable Magnesium Alloys
20
作者 Bianmei Cao Limei Cao David F. Kallmes 《Materials Sciences and Applications》 2024年第8期245-252,共8页
Biodegradable magnesium alloys have been widely used in medical implants. But safety concerns were put forward for the high degradation rate of biodegradable magnesium alloy. The optimal biodegradable magnesium alloys... Biodegradable magnesium alloys have been widely used in medical implants. But safety concerns were put forward for the high degradation rate of biodegradable magnesium alloy. The optimal biodegradable magnesium alloys that give rise to the desired degradation rate hasn’t yet to be defined. Assessing the degradation rate of biodegradable magnesium alloys involves in vitro testing, in vivo testing, numerical modeling, understanding the factors influencing their degradation in physiological environments, biocompatibility testing, and clinical studies. It is important to standardize analytical tools aimed at assessing the degradation rate of biodegradable magnesium alloys. It is advisable to identify the threshold for safe degradation rate of biodegradable magnesium alloys in biomedical applications. 展开更多
关键词 Magnesium Alloys Biomedical application BIODEGRADATION Degradation rate BIOCOMPATIBILITY
下载PDF
上一页 1 2 162 下一页 到第
使用帮助 返回顶部