With the change of cropping system in the middle reaches of the Yangtze River,the planting area of autumn maize is gradually increasing.However,the cultivation techniques are still under improvement for higher yield a...With the change of cropping system in the middle reaches of the Yangtze River,the planting area of autumn maize is gradually increasing.However,the cultivation techniques are still under improvement for higher yield and nitrogen efficiency of autumn maize.Increase in planting density with reduced nitrogen fertilizer application is one of the important paths to achieve high yield and high nitrogen utilization efficiency.Meanwhile,the effect needs to be verified for autumn maize.The semi-compact autumn maize variety Qinyu 58 was planted under different planting densities and nitrogen fertilizer amounts with the split plot design.Different nitrogen application rates were arranged in the main plots,including the conventional nitrogen application(N300,300 kg/hm^2),30%reduction from the conventional treatment(N210,210 kg/hm^2)and no nitrogen application(N0).Different planting densities were arranged in the sub-split plots,including the conventional planting density(D60,60000 plants/hm2),medium density(D78,78000 plants/hm^2)and high density(D93,93000 plants/hm2).The effects of nitrogen fertilizer,planting density and their interaction effects on canopy structure,dry matter accumulation,yield and nitrogen use efficiency of autumn maize were studied.The nitrogen application rate and planting density had obvious interaction effects on the yield formation of autumn maize.Compared with the conventional cultivation(N300D60),increasing the planting density with 30%reduction in nitrogen application(N210)can obviously increase the canopy light interception rate,LAI,dry matter accumulation and yield.However,there was no significant change in canopy light interception rate,LAI,dry matter accumulation,grain weight and yield between D93 and D78.Compared with N300D60,nitrogen translocation efficiency and nitrogen contribution proportion to grain nitrogen did not change significantly in autumn maize grown under N210 and D78 treatments,whereas nitrogen partial productivity,nitrogen agronomic efficiency and recovery and utilization efficiency of nitrogen fertilizer increased significantly.Moreover,high density(D93)planting at N210 plots significantly improved nitrogen transport efficiency and utilization efficiency in autumn maize.Therefore,the suitable planting density of the autumn maize variety Qinyu 58 in Hubei Province is recommended a value of 78000 plants/hm^2,with the nitrogen application rate of 210 kg/hm2,which can achieve the target of higher yield by increasing density and reducing nitrogen.展开更多
目的评价低脂饮食(LFD)与低碳水化合物饮食(LCD)干预非酒精性脂肪肝(NAFLD)的效果。方法利用PubMed、EMBASE、Medline、Cochrane library、web of science、中国知网(CNKI)、万方数据等数据库,检索自建库至2019年1月发表的有关于LFD与LC...目的评价低脂饮食(LFD)与低碳水化合物饮食(LCD)干预非酒精性脂肪肝(NAFLD)的效果。方法利用PubMed、EMBASE、Medline、Cochrane library、web of science、中国知网(CNKI)、万方数据等数据库,检索自建库至2019年1月发表的有关于LFD与LCD干预NAFLD患者的临床随机对照试验,根据饮食干预中碳水化合物的比例将研究分为极低碳水化合物饮食组(VLCKD)、低碳水化合物饮食组(LCD)、中等碳水化合物饮食组(MCD)及高碳水化合物饮食组(HCD)并使用Stata11.0对所获数据进行meta分析。结果共纳入符合要求的文献11篇,共计420例NAFLD患者。分析结果显示:VLCKD组相对于LFD组,在改善NAFLD患者体质量、TC、TG、HDL、LDL、ALT、AST、GGT及肝脏脂肪含量方面差异无统计学意义(P>0.05);MCD饮食较LFD组可以降低NAFLD患者的TG水平(MD=-32.141,95%CI[-58.280,-6.001],P=0.016),但在改善体质量、TC、HDL、LDL、ALT、AST、GGT及肝脂肪含量方面差异无统计学意义(P>0.05);HCD组相对于LFD组可以降低NAFLD患者的TC水平(MD=-0.59,95%CI[-0.979,-0.201],P=0.003),而在改善体质量、TG、HDL、LDL、ALT、AST、GGT及肝脂肪含量方面差异无统计学意义(P>0.05)。结论目前有关LCD与LFD在NAFLD治疗上孰优孰劣的证据仍然缺乏,应该进行更多的调查和循证研究来评估LCD长期作用及稳定性。展开更多
文摘With the change of cropping system in the middle reaches of the Yangtze River,the planting area of autumn maize is gradually increasing.However,the cultivation techniques are still under improvement for higher yield and nitrogen efficiency of autumn maize.Increase in planting density with reduced nitrogen fertilizer application is one of the important paths to achieve high yield and high nitrogen utilization efficiency.Meanwhile,the effect needs to be verified for autumn maize.The semi-compact autumn maize variety Qinyu 58 was planted under different planting densities and nitrogen fertilizer amounts with the split plot design.Different nitrogen application rates were arranged in the main plots,including the conventional nitrogen application(N300,300 kg/hm^2),30%reduction from the conventional treatment(N210,210 kg/hm^2)and no nitrogen application(N0).Different planting densities were arranged in the sub-split plots,including the conventional planting density(D60,60000 plants/hm2),medium density(D78,78000 plants/hm^2)and high density(D93,93000 plants/hm2).The effects of nitrogen fertilizer,planting density and their interaction effects on canopy structure,dry matter accumulation,yield and nitrogen use efficiency of autumn maize were studied.The nitrogen application rate and planting density had obvious interaction effects on the yield formation of autumn maize.Compared with the conventional cultivation(N300D60),increasing the planting density with 30%reduction in nitrogen application(N210)can obviously increase the canopy light interception rate,LAI,dry matter accumulation and yield.However,there was no significant change in canopy light interception rate,LAI,dry matter accumulation,grain weight and yield between D93 and D78.Compared with N300D60,nitrogen translocation efficiency and nitrogen contribution proportion to grain nitrogen did not change significantly in autumn maize grown under N210 and D78 treatments,whereas nitrogen partial productivity,nitrogen agronomic efficiency and recovery and utilization efficiency of nitrogen fertilizer increased significantly.Moreover,high density(D93)planting at N210 plots significantly improved nitrogen transport efficiency and utilization efficiency in autumn maize.Therefore,the suitable planting density of the autumn maize variety Qinyu 58 in Hubei Province is recommended a value of 78000 plants/hm^2,with the nitrogen application rate of 210 kg/hm2,which can achieve the target of higher yield by increasing density and reducing nitrogen.
文摘目的评价低脂饮食(LFD)与低碳水化合物饮食(LCD)干预非酒精性脂肪肝(NAFLD)的效果。方法利用PubMed、EMBASE、Medline、Cochrane library、web of science、中国知网(CNKI)、万方数据等数据库,检索自建库至2019年1月发表的有关于LFD与LCD干预NAFLD患者的临床随机对照试验,根据饮食干预中碳水化合物的比例将研究分为极低碳水化合物饮食组(VLCKD)、低碳水化合物饮食组(LCD)、中等碳水化合物饮食组(MCD)及高碳水化合物饮食组(HCD)并使用Stata11.0对所获数据进行meta分析。结果共纳入符合要求的文献11篇,共计420例NAFLD患者。分析结果显示:VLCKD组相对于LFD组,在改善NAFLD患者体质量、TC、TG、HDL、LDL、ALT、AST、GGT及肝脏脂肪含量方面差异无统计学意义(P>0.05);MCD饮食较LFD组可以降低NAFLD患者的TG水平(MD=-32.141,95%CI[-58.280,-6.001],P=0.016),但在改善体质量、TC、HDL、LDL、ALT、AST、GGT及肝脂肪含量方面差异无统计学意义(P>0.05);HCD组相对于LFD组可以降低NAFLD患者的TC水平(MD=-0.59,95%CI[-0.979,-0.201],P=0.003),而在改善体质量、TG、HDL、LDL、ALT、AST、GGT及肝脂肪含量方面差异无统计学意义(P>0.05)。结论目前有关LCD与LFD在NAFLD治疗上孰优孰劣的证据仍然缺乏,应该进行更多的调查和循证研究来评估LCD长期作用及稳定性。
