North China Plain(NCP) is the primary winter wheat production region in China, characterized by smallholder farming systems. Whereas the winter wheat average yield of smallholder farmers is currently low, the yield po...North China Plain(NCP) is the primary winter wheat production region in China, characterized by smallholder farming systems. Whereas the winter wheat average yield of smallholder farmers is currently low, the yield potential and limiting factors driving the current yield gap remain unclear. Therefore, increasing the wheat yield in NCP is essential for the national food security. This study monitored wheat yield, management practices and soil nutrient data in 132 farmers’ fields of Xushui County, Baoding City, Hebei Province during 2014–2016. These data were analyzed using variance and path analysis to determine the yield gap and the contribution of yield components(i.e., spikes per hectare, grain number per spike and 1 000-grain weight) to wheat yield. Then, the limiting factors of yield components and the optimizing strategies were identified by a boundary line approach. The results showed that the attainable potential yield for winter wheat was 10 514 kg ha^–1. The yield gaps varied strongly between three yield groups(i.e., high, middle and low), which were divided by yield level and contained 44 farmers in each group, and amounted to 2 493, 1 636 and 814 kg ha^–1, respectively. For the three yield components, only spikes per hectare was significantly different(P<0.01) among the three yield groups. For all 132 farmers’ fields, correlation between yield and spikes per hectare(r=0.51, P<0.01), was significantly positive, while correlations with grain number per spike(r=–0.16) and 1 000-grain weight(r=–0.10) were not significant. The path analysis also showed that the spikes per hectare of winter wheat were the most important component to the wheat yield. Boundary line analysis showed that seeding date was the most limiting factor of spikes per hectare with the highest contribution rate(26.7%), followed by basal N input(22.1%) and seeding rate(14.5%), which indicated that management factors in the seeding step were the most important for affecting spikes per hectare. For desired spikes per hectare(>6.598×10^6 ha^–1),the seeding rate should range from 210–300 kg ha^–1, seeding date should range from 3th to 8th October, and basal N input should range from 90–180 kg ha^–1. Compared to these reasonable ranges of management measures, most of the farmers’ practices were not suitable, and both lower and higher levels of management existed. It is concluded that the strategies for optimizing yield components could be achieved by improving wheat seeding quality and optimizing farmers’ nutrient management practices in the NCP.展开更多
Based on the analysis of the grain supply and demand gap’s current situation in China, this paper establishes an indicator system for the influence factors of grain supply and demand gap. Then this paper calculates t...Based on the analysis of the grain supply and demand gap’s current situation in China, this paper establishes an indicator system for the influence factors of grain supply and demand gap. Then this paper calculates the correlation degree between the main grain varieties’ supply and demand gap and its influence factors. The results show that sown area and unit yield have the greatest impact on wheat supply and demand gap;per capita disposable income and unit yield have the greatest impact on corn supply and demand gap;per capita disposable income and agricultural mechanization level have the greatest impact on the supply and demand gap of soybean and rice. From the analysis results, we can obtain the difference between the factors affecting the grain supply and demand gap, and provide a certain theoretical basis and new ideas for the balance of grain supply and demand in China.展开更多
Taking the relevant data of 27 provinces in China during 2013 and 2017 as samples,this paper firstly measured the agricultural total factor productivity( TFP) using Malmquist index method. Then,it built the panel data...Taking the relevant data of 27 provinces in China during 2013 and 2017 as samples,this paper firstly measured the agricultural total factor productivity( TFP) using Malmquist index method. Then,it built the panel data model,and empirically tested the impacts of agricultural TFP on the income gap between urban and rural residents. The results show that the improvement in agricultural TFP can promote the narrowing of the income gap between urban and rural residents,and the factors such as urbanization level and industrial structure also have significant impacts on the income gap between urban and rural residents. On the basis of these,it came up with recommendations,including increasing agricultural human capital investment and establishing agricultural production research institutions.展开更多
目的:通过对神经侧支发芽过程中外源性神经生长因子对生长相关蛋白-43(gr owt h associ at ed pr ot ei n-43,GAP-43)的调控,探讨神经侧支发芽再生的机制。方法:SD大鼠共40只,建立胫腓神经端侧吻合模型,随机分为神经生长因子(nervegr ow...目的:通过对神经侧支发芽过程中外源性神经生长因子对生长相关蛋白-43(gr owt h associ at ed pr ot ei n-43,GAP-43)的调控,探讨神经侧支发芽再生的机制。方法:SD大鼠共40只,建立胫腓神经端侧吻合模型,随机分为神经生长因子(nervegr owt h f act or,NGF)组和生理盐水(SAL)组,各组又分为1周、2周、4周和8周组。切取吻合近端和远端神经纵切片标本,进行GAP-43的免疫组织化学反应,并结合计算机图像分析进行反应强度的半定量分析。结果:NGF组GAP-43表达显著增高。结论:应用NGF可以促进端侧吻合后神经侧支发芽。展开更多
基金supported by the National Basic Research Program of China (2015CB150405)the Special Fund for Agro-scientific Research in the Public Interest, China (201103003)
文摘North China Plain(NCP) is the primary winter wheat production region in China, characterized by smallholder farming systems. Whereas the winter wheat average yield of smallholder farmers is currently low, the yield potential and limiting factors driving the current yield gap remain unclear. Therefore, increasing the wheat yield in NCP is essential for the national food security. This study monitored wheat yield, management practices and soil nutrient data in 132 farmers’ fields of Xushui County, Baoding City, Hebei Province during 2014–2016. These data were analyzed using variance and path analysis to determine the yield gap and the contribution of yield components(i.e., spikes per hectare, grain number per spike and 1 000-grain weight) to wheat yield. Then, the limiting factors of yield components and the optimizing strategies were identified by a boundary line approach. The results showed that the attainable potential yield for winter wheat was 10 514 kg ha^–1. The yield gaps varied strongly between three yield groups(i.e., high, middle and low), which were divided by yield level and contained 44 farmers in each group, and amounted to 2 493, 1 636 and 814 kg ha^–1, respectively. For the three yield components, only spikes per hectare was significantly different(P<0.01) among the three yield groups. For all 132 farmers’ fields, correlation between yield and spikes per hectare(r=0.51, P<0.01), was significantly positive, while correlations with grain number per spike(r=–0.16) and 1 000-grain weight(r=–0.10) were not significant. The path analysis also showed that the spikes per hectare of winter wheat were the most important component to the wheat yield. Boundary line analysis showed that seeding date was the most limiting factor of spikes per hectare with the highest contribution rate(26.7%), followed by basal N input(22.1%) and seeding rate(14.5%), which indicated that management factors in the seeding step were the most important for affecting spikes per hectare. For desired spikes per hectare(>6.598×10^6 ha^–1),the seeding rate should range from 210–300 kg ha^–1, seeding date should range from 3th to 8th October, and basal N input should range from 90–180 kg ha^–1. Compared to these reasonable ranges of management measures, most of the farmers’ practices were not suitable, and both lower and higher levels of management existed. It is concluded that the strategies for optimizing yield components could be achieved by improving wheat seeding quality and optimizing farmers’ nutrient management practices in the NCP.
文摘Based on the analysis of the grain supply and demand gap’s current situation in China, this paper establishes an indicator system for the influence factors of grain supply and demand gap. Then this paper calculates the correlation degree between the main grain varieties’ supply and demand gap and its influence factors. The results show that sown area and unit yield have the greatest impact on wheat supply and demand gap;per capita disposable income and unit yield have the greatest impact on corn supply and demand gap;per capita disposable income and agricultural mechanization level have the greatest impact on the supply and demand gap of soybean and rice. From the analysis results, we can obtain the difference between the factors affecting the grain supply and demand gap, and provide a certain theoretical basis and new ideas for the balance of grain supply and demand in China.
文摘Taking the relevant data of 27 provinces in China during 2013 and 2017 as samples,this paper firstly measured the agricultural total factor productivity( TFP) using Malmquist index method. Then,it built the panel data model,and empirically tested the impacts of agricultural TFP on the income gap between urban and rural residents. The results show that the improvement in agricultural TFP can promote the narrowing of the income gap between urban and rural residents,and the factors such as urbanization level and industrial structure also have significant impacts on the income gap between urban and rural residents. On the basis of these,it came up with recommendations,including increasing agricultural human capital investment and establishing agricultural production research institutions.
文摘目的:通过对神经侧支发芽过程中外源性神经生长因子对生长相关蛋白-43(gr owt h associ at ed pr ot ei n-43,GAP-43)的调控,探讨神经侧支发芽再生的机制。方法:SD大鼠共40只,建立胫腓神经端侧吻合模型,随机分为神经生长因子(nervegr owt h f act or,NGF)组和生理盐水(SAL)组,各组又分为1周、2周、4周和8周组。切取吻合近端和远端神经纵切片标本,进行GAP-43的免疫组织化学反应,并结合计算机图像分析进行反应强度的半定量分析。结果:NGF组GAP-43表达显著增高。结论:应用NGF可以促进端侧吻合后神经侧支发芽。
