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The Difficulties in Raising Fertility Rates-The Deficiencies and Improvements of the Maternity Protection System for Women of Childbearing Age 被引量:1
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作者 Jia Yujiao Huang Deyuan 《Contemporary Social Sciences》 2020年第3期143-154,共12页
Fertility policies consist of not only the legal definition of"procreation",but also the"maternity"protection system,the complete set of selfconsistent social relations and policy systems formed ar... Fertility policies consist of not only the legal definition of"procreation",but also the"maternity"protection system,the complete set of selfconsistent social relations and policy systems formed around"fertility".Gender,labor and intergenerational relations are the cornerstones of a fertility policy system.In this framework,we focus on women of childbearing age as the main actors of reproductive behaviors,to research how drastic social changes have altered women,the above-mentioned relations,and policy support and analyze the structural factors that restrict women’s reproductive intentions.The traditional male breadwinner model,which can no longer prevail and the relatively slow development of maternity protection policies and service systems leave women of childbearing age in a dilemma between working hours and birth timing.Therefore,maternity protection policies should focus on improved decommodification of maternity insurance and the construction of women and children’s social welfare systems including childcare social service systems. 展开更多
关键词 reproductive behaviors social support for women fertility policy fertility rate
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Are the total fertility rates of men and women different at below-replacement levels?An answer obtained from the G7 countries
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作者 Nan Li 《China Population and Development Studies》 2023年第3期281-293,共13页
A child is born to a father and a mother.This fact,however,is yet to be recognized by demography,in which fertility refers to women’s natural ability to give birth.The main reason for the absence of men is that data ... A child is born to a father and a mother.This fact,however,is yet to be recognized by demography,in which fertility refers to women’s natural ability to give birth.The main reason for the absence of men is that data on births are more often available for women than for men.But in the last few decades,data availability has greatly improved.Recent studies show that total fertility rates(TFRs)of men can be calculated for most countries in the world and that the difference between the TFRs of men and women can be quite large.For low-fertility countries,nonetheless,these studies show little difference between the TFRs of men and women,giving rise to the question:Is men’s fertility worth further investigation?To avoid ambiguity in describing a particular difference as small or big,this paper provides a formula for probabilistic TFRs.Using hypothesis test on probabilistic TFRs,we can say that the difference between the TFRs of men and women is statistically significant for all the G7 countries,except for France.To explain the differences between the TFRs of men and women,this study uses models of stable populations and concludes that the one-sex stable population models cannot explain the results whereas a two-sex joint stable population model can do so.By using the two-sex population model,we can explain why the TFR of men in France is almost the same as that of women,and why it is lower than that of women in the other six G7 countries.More specifically,by using the model,we can help explain 76%of the variance in the difference between the TFRs of men and women.Future studies may be able to show that men’s TFR is significantly lower than women’s in other countries too and explain why it is so.The above findings,however,require closer attention and further investigation,because low fertility could lead to socioeconomic problems.Beyond TFRs,extending fertility studies from women to men as well,that is,conducting fertility studies on both women and men,will fundamentally improve our knowledge about fertility age patterns,trends,determinants,policies and other related issues. 展开更多
关键词 Total fertility rate of men Probabilistic total fertility rate Hypothesis test Explanation model
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Human circBOULE RNAs as potential biomarkers for sperm quality and male infertility
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作者 Liping Cheng He Jin +3 位作者 Tianheng Xiao Xiaoyu Yang Tingting Zhao Eugene Yujun Xu 《Journal of Biomedical Research》 CAS CSCD 2024年第5期473-484,I0003-I0008,共18页
Reliable molecular biomarkers to predict fertility remain scarce.The current study investigated the potential of testis-specific circBOULE RNAs as biomarkers for male infertility and sperm quality.Using reverse transc... Reliable molecular biomarkers to predict fertility remain scarce.The current study investigated the potential of testis-specific circBOULE RNAs as biomarkers for male infertility and sperm quality.Using reverse transcription-PCR and real-time reverse transcription-PCR assays,we identified seven circular RNAs from the human BOULE gene in human sperm.We observed that the expression level of circEx3-6 was significantly reduced in asthenozoospermia,while the expression levels of both circEx2-6 and circEx2-7 were decreased in terato-zoospermia,compared with the controls.Furthermore,we demonstrated that the expression level of circEx2-6 was negatively correlated with the sperm DNA fragmentation index,and the expression level of circEx2-7 was correlated with both fertilization and cleavage rates in those treated with the assisted reproductive technologies.Further functional analyses in a transgenic fly model supported the roles of circBOULE RNAs in sperm development and human male fertility.Collectively,our findings support that sperm circBOULE RNAs may serve as diagnostic biomarkers for assessing sperm motility and DNA quality.Therefore,clinical application and significance of sperm circBOULE RNAs in the assisted reproductive technologies warrant further investigation. 展开更多
关键词 human circBOULE RNAs sperm DNA fragmentation index fertilization rate cleavage rate semen parameters assisted reproductive technology
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China’s Low Fertility Rate from the Perspective of Gender and Development 被引量:1
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作者 Ji Yingchun Zheng Zhenzhen Li Guanghui 《Social Sciences in China》 2020年第4期169-184,共16页
Fertility and other demographic indicators do not simply follow the ups and downs of policy.In order to understand more objectively and accurately the degree of acceptance,impact and actual effect of the unconditional... Fertility and other demographic indicators do not simply follow the ups and downs of policy.In order to understand more objectively and accurately the degree of acceptance,impact and actual effect of the unconditional two-child policy(quanmian erhai zhengce)as well as the long-term trend of China’s fertility rate,we need to proceed from the institutional and cultural context of Chinese society.The complex social mechanisms behind the low fertility situation in China should be interpreted from the perspective of gender and development.Drawing on international theories and lessons learned from past experience,we find,from a gender and development perspective,that women’s workfamily conflict is the key to examining China’s low fertility rate;designing public policy with a gender perspective to promote the participation of government,society,business and multiple male and female actors is a social mechanism that alleviates women’s work-family conflict;and advocating the Marxist gender ideology of equality between men and women and abandoning traditional Confucian patriarchal and familial thinking are the ideological basis for alleviating women’s work-family conflict.In view of the dual identity of women as material producers and social reproducers,promoting the simultaneous development of gender equality in the public and private sectors and alleviating women’s work-family conflicts will make a positive contribution to maintaining a certain fertility rate and level of economic development. 展开更多
关键词 social gender economic development low fertility rate unconditional two-child policy work-family conflict
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Application of Artificial Insemination in Selective Breeding of Native Beef Cattle in Wenzhou
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作者 Ye Chaoqun Liu Junyu +7 位作者 Lv Caihao Liu Xuyan Fu Hao Chen Tianmeng Xu Zijing Xu Da Wu Changhuie Xu Hongxi 《Animal Husbandry and Feed Science》 CAS 2024年第1期9-12,共4页
[Objective]The paper was to improve the quality and growth rate of native yellow cattle in Wenzhou.[Method]Three groups of cattle were subjected to artificial insemination using frozen semen from Wagyu bull.The groups... [Objective]The paper was to improve the quality and growth rate of native yellow cattle in Wenzhou.[Method]Three groups of cattle were subjected to artificial insemination using frozen semen from Wagyu bull.The groups consisted of 20 native yellow cattle,20 Angus catle,and 20 Luxi yellow cattle.The heifers were subsequently evaluated for body size and body weight,and underwent treatment with estrus synchronization,artificial insemination,and early pregnancy diagnosis.[Result]The mean body size and body weight of native yellow cattle were found to be significantly lower than those of Angus cattle and Luxi yellow cattle(P<0.05).The estrus synchronization rate and mating rate of native yellow cattle were both 100%,while the corresponding rates for Angus cattle and Luxi yellow cattle were 90%and 95%,respectively.The ultrasound examination conducted on the 32m day following the mating revealed a distinct image of gestation sac,which,when considered alongside the findings of the rectal examination,may be indicative of pregnancy.The conception rates were 75%,72%,and 74%for native yllow cattle,Angus cattle,and Luxi yellow cattle,respectively.[Conclusion]The reproductive performance of native beef cattle is relatively superior. 展开更多
关键词 Native cattle in Wenzhou Angus cattle Luxi yellow cattle Artificial insemination Estrus synchronization Fertilization rate
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Effects of Different Nitrogen Fertilizer Rates on Soluble Sugar,Starch and Root Tissue Structure of the Peach Trees
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作者 潘春香 肖艳辉 +1 位作者 新居直祐 中尾義則 《Agricultural Science & Technology》 CAS 2011年第12期1861-1863,共3页
[Objective] The research aimed to provide theoretical basis for the cultivation and production of peach.[Method] The three-year-old seedling peach tree was used as the materials,and NH4NO3 was used as the experimental... [Objective] The research aimed to provide theoretical basis for the cultivation and production of peach.[Method] The three-year-old seedling peach tree was used as the materials,and NH4NO3 was used as the experimental nitrogen fertilizer.Three nitrogen levels,0,3,6 g per pot respectively were set to study the effects of different nitrogen fertilizer on the contents of soluble sugar,starch and internal structure of the root of the peaches.[Result] The contents of soluble sugar of roots and leaves increased with the increase of nitrogen fertilizer level,and the level of 6 g per pot was the highest,which showed extreme differences between the level of 3 g per pot and the control.However,starch contents showed opposite results,which decreased as the level of nitrogen fertilizer increased.Compared with the 3 g per pot level of nitrogen fertilizer and the control,the internal structure of root applied with nitrogen fertilizer of 6 g per pot level had larger fibrovascularcylinder,advanced vascular bundle,small-spaced thin-walled cells,smooth and full cells with smooth cell wall.[Conclusion]Appropriate nitrogen levels can accelerate the accumulation of soluble sugar and the growth of root tissue structure. 展开更多
关键词 PEACH Nitrogen fertilizer rate Soluble sugar STARCH Root tissue structure
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Nitrogen and Phosphorus Runoff Losses from Orchard Soils in South China as Affected by Fertilization Depths and Rates 被引量:25
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作者 ZENG Shu-Cai SU Zhi-Yao +2 位作者 CHEN Bei-Guang WU Qi-Tang OUYANG Ying 《Pedosphere》 SCIE CAS CSCD 2008年第1期45-53,共9页
Fertilizers are heavily applied in orchards of the hilly and mountainous topography of South China and may increase nutrient loadings to receiving waters.A simple runoff collecting system was used to measure the effec... Fertilizers are heavily applied in orchards of the hilly and mountainous topography of South China and may increase nutrient loadings to receiving waters.A simple runoff collecting system was used to measure the effects of different fertilization treatments on total N and P concentrations of surface runoff in a Chinese chestnut (Castanea mollissima Blume) orchard in Dongyuan County,Guangdong Province,China.In such orchards,fertilizer was typically applied in two short furrows or pits on either side of each tree.Treatments included three application depths (surface,10cm and 20 cm),and three application rates (low,median and high).Results showed that 90.5% of the runoff water samples had a total N concentration higher than 0.35 mgL^(-1) and 54.2% had a total P concentration higher than 0.1 mgL^(-1).Fertilizer application at all depths and at all but the lowest rate significantly increased total N and P concentrations in runoff water.Fertilization with chemical compound fertilizer at a soil depth of 20cm produced significantly lower (P<0.05) total N concentration in runoff than both surface and 10-cm depth fertilization,and significantly lower (P<0.05) total P concentration in runoff than surface fertilization.Total N and P concentrations in runoff significantly increased with the application rate of organic fertilizers.With the exception of total P concentrations,which were not significantly different between the control and fertilization at a rate of 119 kg P ha-1 in organic form,all the other fertilization treatments produced significantly higher total N and total P concentrations in runoff than the control.A fertilization depth≥20cm and an application rate≤72 kg N ha^(-1) or 119 kg P ha^(-1) for compound organic fertilizer was suggested to substantially reduce N and P runoff losses from hillslope orchards and to protect receiving waters in South China. 展开更多
关键词 fertilization depth fertilization rate RUNOFF total N total P
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Response of Tomato on Calcareous Soils to Different Seedbed Phosphorus Application Rates 被引量:8
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作者 ZHANG Xiao-Sheng LIAO Hong +3 位作者 CHEN Qing P. CHRISTIE LI Xiao-Lin ZHANG Fu-Suo 《Pedosphere》 SCIE CAS CSCD 2007年第1期70-76,共7页
Field experiments were conducted with five rates (0, 75, 150, 225, and 450 kg P205 ha^-1) of seedbed P fertilizer application to investigate the yield of tomato in response to fertilizer P rate on calcareous soils w... Field experiments were conducted with five rates (0, 75, 150, 225, and 450 kg P205 ha^-1) of seedbed P fertilizer application to investigate the yield of tomato in response to fertilizer P rate on calcareous soils with widely different levels of Olsen P (13-142 mg kg^-1) at 15 sites in some suburban counties of Beijing in 1999. Under the condition of no P fertilizer application, tomato yield generally increased with an increase in soil test P levels, and the agronomic level for soil testing P measured with Olsen method was 50 or 82 mg kg^-1 soil to achieve 85% or 95% of maximum tomato yield, respectively. With regard to marketable yield, in the fields where Olsen-P levels were 〈 50 mg kg^-1, noticeable responses to applied P were observed. On the basis of a linear plateau regression, the optimum seedbed P application rate in the P-insufflcient fields was 125 kg P205 ha^-1 or about 1.5-2 times the P removal from harvested tomato plants. In contrast, in fields with moderate (50 〈 Olsen P 〈 90 mg kg^-1) or high (Olsen P 〉 90 mg kg^-1) available P, there was no marked effect on tomato fruit yield. Field survey data indicated that in most fields with conventional P management, a P surplus typically occurred. Thus, once the soil test P level reached the optimum for crop yield, it was recommended that P fertilizer application be restricted or eliminated to minimize negative environmental effects. 展开更多
关键词 calcareous soils fertilizer P rate soil test P tomato yield vegetable fields
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Net energy yield and carbon footprint of summer corn under different N fertilizer rates in the North China Plain 被引量:4
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作者 WANG Zhan-biao WEN Xin-ya +2 位作者 ZHANG Hai-lin LU Xiao-hong CHEN Fu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2015年第8期1534-1541,共8页
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
关键词 MAIZE nitrogen fertilizer rate grain yield net energy ratio greenhouse gas emissions
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Abundance and Community Composition of Ammonia-Oxidizers in Paddy Soil at Different Nitrogen Fertilizer Rates 被引量:4
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作者 SONG Ya-na LIN Zhi-min 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第4期870-880,共11页
Ammonia oxidation, the first and rate-limiting step of nitrification, is carried out by both ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). However, the relative importance of AOB and AOA to... Ammonia oxidation, the first and rate-limiting step of nitrification, is carried out by both ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). However, the relative importance of AOB and AOA to nitrification in terrestrial ecosystems is not well understood. The aim of this study was to investigate the effect of the nitrogen input amount on abundance and community composition of AOB and AOA in red paddy soil. Soil samples of 10-20 cm (root layer soil) and 0-5 cm (surface soil) depths were taken from a red paddy. Rice in the paddy was fertilized with different rates of N as urea of N1 (75 kg N ha" yr-1), N2 (150 kg N ha~ yrl), N3 (225 kg N ha1 yrl) and CK (without fertilizers) in 2009, 2010 and 2011. Abundance and community composition of ammonia oxidizers was analyzed by real-time PCR and denaturing gradient gel electrophoresis (DGGE) based on amoA (the unit A of ammonia monooxygenase) gene. Archaeal amoA copies in N3 and N2 were significantly (P〈0.05) higher than those in CK and N1 in root layer soil or in surface soil under tillering and heading stages of rice, while the enhancement in bacterial amoA gene copies with increasing of N fertilizer rates only took on in root layer soil. N availability and soil NO3--N content increased but soil NH4+-N content didn't change with increasing of N fertilizer rates. Otherwise, the copy numbers of archaeal amoA gene were higher (P〈0.05) than those of bacterial amoA gene in root lary soil or in surface soil. Redundancy discriminate analysis based on DGGE bands showed that there were no obvious differs in composition of AOA or AOB communities in the field among different N fertilizer rates. Results of this study suggested that the abundance of ammonia-oxidizers had active response to N fertilizer rates and the response of AOA was more obvious than that of AOB. Similarity in the community composition of AOA or AOB among different N fertilizer rates indicate that the community composition of ammonia-oxidizers was relatively stable in the paddy soil at least in short term for three years. 展开更多
关键词 ammonia-oxidizing bacteria ammonia-oxidizing archaea nitrogen fertilizer rates paddy soil
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Use of Several Plant Materials and Chemicals to inhibit Soil Urease Activity and Increase Nitrogen Recovery Rate of Urea by Plant 被引量:6
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作者 XU WEIHONG, WANG ZHENGYIN, JIA ZHONGYUAN, HUANG YUN, YUAN LUJIANG and WANG JUANMEICollege of Resources and Environmental Science, Southwest Agricultural University, Chongqing 400716 (China) 《Pedosphere》 SCIE CAS CSCD 2002年第3期275-282,共8页
Effects of residues of 9 plants, lemon eucalyptus (Eucalyptus citriodoraHook., P_1), robust eucalyptus (E. robusta Smith, P_2), Nepal camphortree (Cinnamomum glanduliferum(Wall.) Nees, P_3), tea (Camellia sinensis (Li... Effects of residues of 9 plants, lemon eucalyptus (Eucalyptus citriodoraHook., P_1), robust eucalyptus (E. robusta Smith, P_2), Nepal camphortree (Cinnamomum glanduliferum(Wall.) Nees, P_3), tea (Camellia sinensis (Linn.) O. Ktze. f., P_4), oleander (Nerium indicum Mill,P_5), rape (Brassica campestris L., P_g), Chinese tallow tree (Sapium sebiferum L., P_7), tung(Vernicia fordii (Hemsl.), P_8), and croton (Croton tiglium L., P_9), 7 chemicals, boric acid (C_1),borax (C_2), oxalic acid (C_3), sodium oxalite (C_4), sodium dihydrogen phosphate (C_6), sodiumsilicate (C_7) and sodium citrate (C_8), and a natural organic substance, humic acid (C_5), onurease activity of a neutral purple soil and recovery of urea nitrogen by maize were studied throughincubation and pot experiments. Hydroquinone (HQ) was applied as the reference inhibitor. Afterincubation at 37℃ for 24 h, 7 inhibitors with higher ability to inhibit urease activity wereselected and then incubated for 14 days at 25℃. Results of the incubation experiments showed thatsoil urease activity was greatly inhibited by them, and the inhibition effect followed an order ofP_2>P_4>C_3>C_2>P_3>C_1>HQ>P_1. The 7 selected materials reduced the accumulative amounts of Nreleased from urea and the maximum urease activity by 11.7%~28.4% and 26.7%~39.7%, respectively,and postponed the N release peak by 2~4 days in the incubation period of 14 days under constanttemperature, as compared to the control (no inhibitor). In the pot experiment with the 7 materialsat two levels of addition, low (L) and high (H), the C_1 (H), C_3 (H), C_1 (L), P_4 (L) and C_2 (L)treatments could significantly increase the dry weights of the aboveground parts and the totalbiomass of the maize plants and the apparent recovery rate of urea-N was increased by 6.3%~32.4% ascompared to the control (no hibitor). 展开更多
关键词 CHEMICALS plant materials recovery rate of fertilizer nitrogen ureaseactivity
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Influence of Acupuncture on Idiopathic Male Infertility in Assisted Reproductive Technology 被引量:1
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作者 张明敏 黄光英 +2 位作者 陆付耳 W.E Paulus K.Sterzik 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2002年第3期228-230,共3页
The clinical effects of acupuncture on idio pathic male infertility in sperm parameter and on therapeutic results in assiste d reproductive technology were investigated. 22 patients failed in intracytoplas mic sperm i... The clinical effects of acupuncture on idio pathic male infertility in sperm parameter and on therapeutic results in assiste d reproductive technology were investigated. 22 patients failed in intracytoplas mic sperm injection (ICSI) with idiopathic male infertility were treated with ac upuncture twice weekly for 8 weeks, followed by ICSI treatment again. The sperm concentration, motility, morphology, fertilization rates and embryo quality were observed. Quick sperm motility after acupuncture(18.3 %±9.6 %) was significa ntly improved as compared with that before treatment (11.0 %±7.5 %, P <0.01) . The normal sperm ratio was increased after acupuncture (21.1 %±10.4 % vs 16.2 %± 8.2 %, P <0.05). The fertilization rates after acupuncture (66.2 %) were obviously higher than that before treatment (40.2 %, P <0.01). There was no significant difference in sperm concentration and general sperm motility between before and after acupuncture. The embryo quality after acupuncture was improved , but the difference between them was not significant ( P >0.05). Acupuncture can improve sperm quality and fertilization rates in assisted reproductive techn ology. 展开更多
关键词 ACUPUNCTURE intracytoplasmic sperm injection fertilization rates embryo quality
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Research on the Behavior and Egg Fertilization Rate of Dwarf Layers and White Leghorn Chickens Fed in Floor-Rearing System
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作者 Long Liu Aiqiao Liu +3 位作者 Baogui Zhou Shoushan Du Peng Hai ZhonghuaNing 《Journal of Agricultural Science and Technology(A)》 2014年第1期86-92,共7页
Influenced by animal welfare requirements and expensive labor cost, producers tend to feed layers in non-cage system such as floor rearing. With the development of commercial lines of dwarf layers, the property of dwa... Influenced by animal welfare requirements and expensive labor cost, producers tend to feed layers in non-cage system such as floor rearing. With the development of commercial lines of dwarf layers, the property of dwarf layers' natural mating is drawing more and more attention. In this study, the authors hybridized Nongda Ill dwarf layers with White Leghorn chickens in floor-rearing system to research whether dwarf layers had defect in natural mating. Two steps of experiments were performed. The authors detected the fertilization rate of collected eggs, observed chickens' behavior in step I when a hen from other group was suddenly put into and recorded copulation number of every group in step II from 7:30 to 19:30. The results indicated that drawf cocks were as good as Leghorn cocks in natrual mating under floor-rearing system while drawf hens were better than Leghorn hens. Observation results showed no difference on reaction to intermixed hens between drawf layers and Leghorn layers. The best proportion of male to female for drawf layers was 1:8 in this experiment and dwarf cocks tended to mate dwarf hens rather than Leghorn hens. 展开更多
关键词 Dwarf layer BEHAVIOR natural mating fertilization rate floor-rearing.
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Growth Parameters of DK8031 Maize Variety as Affected by Varying Irrigation and Nitrogen Fertilizer Rates in Embu County, Kenya
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作者 Charles Nyambane Onyari Antony Mwangi Kibe Samuel Mwonga 《Journal of Environmental Science and Engineering(A)》 2015年第8期432-444,共13页
Determination of crop growth parameters of maize helps assess the performance of the crop for food security. A study was conducted in two seasons covering 2012 and 2013 to establish optimal irrigation and nitrogen fer... Determination of crop growth parameters of maize helps assess the performance of the crop for food security. A study was conducted in two seasons covering 2012 and 2013 to establish optimal irrigation and nitrogen fertilizer rates for drought tolerant hybrid maize (Zea mays L.), DK8031 variety, in sandy loam soils using furrow irrigation. Four additive irrigation levels (119.05 mm, 238.10 mm, 357.15 mm and 476.2 mm) were allocated the main plots while five nitrogen fertilizer rates (0 kg/ha, 60, 75 kg/ha, 90 kg/ha and 100 kg/ha) were allocated the sub-plots. Both irrigation and nitrogen fertilizer treatments significantly enhanced crop growth parameters under consideration. Stand count per treatment plot, plant height and number of leaves per ranged from 45-59 plants/plot, 215-238 cm and 14-16 leaves respectively. It was concluded that use of supplementary irrigation and phased nitrogen fertilizer rates for maize growing in areas such as Embu can greatly promote crop growth. 展开更多
关键词 Maize IRRIGATION nitrogen fertilizer rates plant height leaves per plant.
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Evaluation of Variable Rate Technology for Fertilizer Application in Permanent Pastures
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作者 J. M. Serrano J. M. Peca Shahidian 《Journal of Agricultural Science and Technology(A)》 2011年第4X期489-499,共11页
This paper describes the field tests carried out to evaluate the new Vicon RS-EDW centrifugal fertilizer spreader, to be used in Precision Agriculture. The results of initial dynamic calibration tests showed a signifi... This paper describes the field tests carried out to evaluate the new Vicon RS-EDW centrifugal fertilizer spreader, to be used in Precision Agriculture. The results of initial dynamic calibration tests showed a significant and systematic difference between the application rates of the two discs (about 20%). This difference had to be corrected by the manufacturer that carried out the necessary changes to the electric actuators. The fertilizer spreader had good distribution homogeneity, considering different working velocities and different positions in the parcel. The pattern distribution curve for 18% super phosphate fertilizer led to an effective working width of 28 meters, with a coefficient of variation of 15%. The longitudinal test, under experimental working conditions led to a machine delay time of 6-7 seconds. The results show an actual fertilization application density between 74%-90% of that determined for each location. These results confirm that the spreader can be used to spread fertilizer differentially in the field. 展开更多
关键词 Calibration centrifugal fertilizer spreader evaluation precision agriculture variable rate technology.
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Do Chinese Women Face Subtle Discrimination in Job Hiring?
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作者 Shelly Y.Wu 《Psychology Research》 2023年第12期609-613,共5页
Gender discrimination has long been the problem that exists in the entire world,including China.However,as more and more people are focusing on the general gender discrimination,the group recognized an extension of su... Gender discrimination has long been the problem that exists in the entire world,including China.However,as more and more people are focusing on the general gender discrimination,the group recognized an extension of such discrimination-pregnancy discrimination in job hiring(the discrimination that women who are pregnant or have the inclination to pregnancy receive in hiring).The possible subtle pregnancy discrimination may be one of the main causes that lead to the declining fertility rate in China.The group decided to conduct an experiment to determine whether women are receiving more subtle discrimination in job hiring due to their identity as mother than men with children,men without children,and women without children.Using the form of questionary and resumes,the team found that Chinese women are indeed enduring subtle discrimination in work hiring.The experiment highlights the importance to promote further equality among women.However,there are some confounding variables,like the level of patient of the HR who reads the resume,affecting the ultimate result of the study.Keywords:gender discrimination,women’s career,Chinese job market,pregnancy discrimination,fertility rate in China. 展开更多
关键词 gender discrimination women’s career Chinese job market pregnancy discrimination fertility rate in China
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Effects of a New Long-term Controlled-release Fertilizer on Growth and Development and Yield of Summer Maize 被引量:3
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作者 史桂芳 董浩 +4 位作者 毕军 夏光利 朱国梁 牟小翎 孙国波 《Agricultural Science & Technology》 CAS 2016年第10期2300-2302,2307,共4页
[Objective] The aim was to select the optimal amount of controlled-release fertilizer and provide theoretical references for controlled-release fertilizers use in summer maize. [Method] Long-term controlled-release fe... [Objective] The aim was to select the optimal amount of controlled-release fertilizer and provide theoretical references for controlled-release fertilizers use in summer maize. [Method] Long-term controlled-release fertilizers were applied once at sowing summer maize to explore effects on maize growth, yield, economic profits and environment. [Result] Maize yield reduced a little in the treatment group with 60% CRF, and increased in varying degrees in the rest groups in the range of 1.1%-7.4%, and some showed significant differences. [Conclusion] Controlled-release fertilizers can be applied once at the amount of 80% common fertilizer's, with con- sideration of maize yield, nitrogen use rate and economic profits, which is beneficial for summer maize application and promotion in North China. 展开更多
关键词 Long-term controlled release fertilizer Summer maize YIELD Nitrogen fertilizer use rate
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Grain Crop Fertilization Status and Factors Influencing Farmers' Decision Making on Fertilizer Use: China Case Study 被引量:5
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作者 闫湘 金继运 梁鸣早 《Agricultural Science & Technology》 CAS 2016年第10期2394-2398,2440,共6页
[Objective] China is the world's largest fertilizer consumer. Fertilizer plays an important role in maintaining China's food security. Along with population and economic growth, overuse of fertilizers has caused ser... [Objective] China is the world's largest fertilizer consumer. Fertilizer plays an important role in maintaining China's food security. Along with population and economic growth, overuse of fertilizers has caused serious environmental problems, such as soil acidification, decline in soil organic carbon, and agricultural non-point source pollution. This study aimed to analyze the factors influencing farmers" decision making on fertilizer use, and provide policy recommendations on ways to affect fertilization. [Method] An econometric model reflecting fertilization of rural households was estimated from a survey distributed to 1 043 households randomly selected from 19 provinces in China. [Result] Results of the study showed that education years of fertilizer decision maker, fertilizer quality, organic fertilizer application, fertilizer price, and agricultural product price had significant effects on the fertilizer application rate at 1% level. Soil nutrient affected the fertilizer application rate at 10% level. [Conclusion] Policies aimed at improving the reasonable use of fertilizer should focus on the regulation of chemical fertilizer price, foundation of the organic-inorganic fertilizer system, soil testing, formulated fertilization, and agricultural extension service. 展开更多
关键词 FARMERS Fertilizer application rate Influencing factors Double logarith- mic model
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Fair Plan 9: Engineering Human Population to Help Safeguard Earth’s Climate
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作者 Michael E. Schlesinger 《Atmospheric and Climate Sciences》 2016年第2期310-318,共9页
Our Fair Plan to Safeguard Earth’s Climate reduces the emission of greenhouse gases to zero over the 80-year time period 2020 to 2100. To accomplish this, humanity must reduce its carbon intensity—the amount of CO&l... Our Fair Plan to Safeguard Earth’s Climate reduces the emission of greenhouse gases to zero over the 80-year time period 2020 to 2100. To accomplish this, humanity must reduce its carbon intensity—the amount of CO<sub>2</sub> emitted per unit of energy—and its energy intensity—the amount of energy needed to generate a unit of Gross World Product. As shown in our Fair Plan 8 paper, reducing the future growth of the human population can also contribute to the reduction in greenhouse-gas emissions. Here, we explore this further. We project the historical decrease in Total Fertility Rate (TFR) across the 21<sup>st</sup> century toward its logistical asymptotic Reference value of 2.04 Births Per Woman (BPW). We then engineer the asymptotic TFR beginning in 2020 to 1.95, 1.85, 1.75, 1.65 & 1.55 BPW. We project the population across the 21<sup>st</sup> century for the Reference and engineered TFRs. We do so using the results of Basten, Lutz and Scherbov (2013) for the population evolution across the 21<sup>st</sup> century for 8 constant TFR values (=2.50, 2.25, 2.00, 1.75, 1.50, 1.25, 1.00 & 0.75 BPW). We find that purposefully engineering the asymptotic TFR can significantly contribute to achieving the reduction in greenhouse-gas emissions needed to transition to our Fair Plan to Safeguard Earth’s Climate. 展开更多
关键词 Climate Change Fair Plan Population Engineering Total fertility rate
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Nitrogen Runoff and Leaching Losses During Rice-Wheat Rotations in Taihu Lake Region,China 被引量:69
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作者 TIAN Yu-Hua YIN Bin +2 位作者 YANG Lin-Zhang YIN Shi-Xue ZHU Zhao-Liang 《Pedosphere》 SCIE CAS CSCD 2007年第4期445-456,共12页
Although nitrogen (N) loss through runoff and leaching from croplands is suspected to contribute to the deterioration of surrounding water systems, there is no conclusive evidence for paddy soils to prove this hypot... Although nitrogen (N) loss through runoff and leaching from croplands is suspected to contribute to the deterioration of surrounding water systems, there is no conclusive evidence for paddy soils to prove this hypothesis. In this study, field plot experiments were conducted to investigate N losses through runoff and leaching for two consecutive years with 3 N fertilization rates in rice (Oryza sativa L.)-wheat (Triticum aestivum L.) rotations in the Taihu Lake region, China. A water collection system was designed to collect runoff and leachates for both the rice and wheat seasons. Results showed that dissolved N (DN), rather than particulate N (PN), was the main form of N loss by runoff. The NO3^--N concentration in runoff was between 0.1 and 43.7 mg L^-1, whereas the NH4^+-N concentration ranged from below detection limit to 8.5 mg L^-1. Total N (TN) loads by runoff were 1.0-17.9 and 5.2-38.6 kg ha^-1 during rice and wheat seasons, respectively, and the main loss occurred at the early growing stage of the crops. Nitrogen concentrations in leachates during the rice seasons were below 1.0 mg L^-1 and independent of the N application rate, whereas those during the wheat season increased to 8.2 mg L^-1 and were affected by the fertilizer rate. Annual losses of TN through runoff and leaching were 13.7-48.1 kg ha^-1 from the rice-wheat cropping system, accounting for 5.6%-8.3% of the total applied N. It was concluded that reduction in the N fertilization rate, especially when the crop was small in biomass, could lower the N pollution potential for water systems. 展开更多
关键词 LEACHING N fertilization rate N loss paddy soil RUNOFF
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