The border effect(BE)is widely observed in crop field experiments,and it has been extensively studied in many crops.However,only limited attention has been paid to the BE of ratoon rice.We conducted field experiments ...The border effect(BE)is widely observed in crop field experiments,and it has been extensively studied in many crops.However,only limited attention has been paid to the BE of ratoon rice.We conducted field experiments on ratoon rice in Qichun County,Hubei Province,Central China in 2018 and 2019 to compare the BE in the main and ratoon crops,and to quantify the contribution of BE in the main crop to that in the ratoon crop.The BE of two hybrid varieties was measured for the outermost,second outermost,and third outermost rows in each plot of both crops.To determine the contribution of BE between the two crops,portions of hills in the outermost and second outermost rows were uprooted during the harvest of the main crop so that the second and third outermost rows then became the outermost rows in the ratoon crop.Overall,the BE on grain yield was greater in the main crop than in the ratoon crop.In the main crop,the BE on grain yield was 98.3%in the outermost row,which was explained by the BE on panicles m^(–2),spikelets/panicle,spikelets m^(–2),and total dry weight.In the ratoon crop,the BE on grain yield was reduced to 60.9 and 27.6%with and without the contribution of the BE in the main crop,respectively.Consequently,55.1%of the BE on grain yield in the ratoon crop was contributed from the main crop.High stubble dry weight and non-structural carbohydrate(NSC)accumulation at the harvest of the main crop were responsible for the contribution of BE in the main crop to that in the ratoon crop.Our results suggest that increases in stubble dry weight and NSC accumulation at the harvest of the main crop could be important strategies for developing high-yielding cropping practices in the rice ratooning system.展开更多
Nitrogen(N) and seeding rates are important factors affecting grain yield and N use efficiency(NUE) in directseeded rice. However, these factors have not been adequately investigated on direct-seeded and double-season...Nitrogen(N) and seeding rates are important factors affecting grain yield and N use efficiency(NUE) in directseeded rice. However, these factors have not been adequately investigated on direct-seeded and double-season rice(DDR) in Central China. The objective of this study was to evaluate the effects of various N and seeding rates on the grain yield and NUE of an ultrashort-duration variety grown under DDR. Field experiments were conducted in 2018 in Wuxue County and 2019 in Qichun County, Hubei Province, China with four N rates and three seeding rates.The results showed that the grain yield of the ultrashort-duration variety ranged from 6.32 to 8.23 t ha–1with a total growth duration of 85 to 97 days across all treatments with N application. Grain yield was increased significantly by N application in most cases, but seeding rate had an inconsistent effect on grain yield. Furthermore, the response of grain yield to the N rates was much higher than the response to seeding rates. The moderate N rates of 100–150 and 70–120 kg N ha–1in the early and late seasons, respectively, could fully express the yield potential of the ultrashort-duration variety grown under DDR. Remarkably higher N responses and agronomic NUE levels were achieved in the early-season rice compared with the late-season rice due to the difference in indigenous soil N supply capacity(INS) between the two seasons. Seasonal differences in INS and N response should be considered when crop management practices are optimized for achieving high grain yield and NUE in ultrashort-duration variety grown under DDR.展开更多
软件定义网络(Software Defined Network,SDN)是实现网络智能化的基础与主要技术途径。当前,商用的SDN网络一般应用于数据中心与软件定义广域网(Software-Defined WAN,SD-WAN)场景,其协议设计着眼于宽带、有线、固定的使用环境,普遍存...软件定义网络(Software Defined Network,SDN)是实现网络智能化的基础与主要技术途径。当前,商用的SDN网络一般应用于数据中心与软件定义广域网(Software-Defined WAN,SD-WAN)场景,其协议设计着眼于宽带、有线、固定的使用环境,普遍存在网络开销大,无法适应动态组网,很难应用于窄带、弱连接的战术边缘场景。基于此,文中在主流商用SDN协议的基础上,从控制平面自动构建、轻量化协议设计与业务流量调度等方面设计了一套面向战术边缘应用的、轻量化的SDN网络控制平面接口协议,仿真验证了所提方案的优越性。文中的研究可为智能化战术信息网络的设计提供一定的参考。展开更多
基金supported by the Major International(Regional)Joint Research Project of National Natural Science Foundation of China(32061143038)the earmarked fund for China Agriculture Research System(CARS-01-20)+1 种基金the National High Technology Research and Development Program of China(the 863 Project,2014AA10A605)the Fundamental Research Funds for the Central Universities,China(2662020ZKPY015).
文摘The border effect(BE)is widely observed in crop field experiments,and it has been extensively studied in many crops.However,only limited attention has been paid to the BE of ratoon rice.We conducted field experiments on ratoon rice in Qichun County,Hubei Province,Central China in 2018 and 2019 to compare the BE in the main and ratoon crops,and to quantify the contribution of BE in the main crop to that in the ratoon crop.The BE of two hybrid varieties was measured for the outermost,second outermost,and third outermost rows in each plot of both crops.To determine the contribution of BE between the two crops,portions of hills in the outermost and second outermost rows were uprooted during the harvest of the main crop so that the second and third outermost rows then became the outermost rows in the ratoon crop.Overall,the BE on grain yield was greater in the main crop than in the ratoon crop.In the main crop,the BE on grain yield was 98.3%in the outermost row,which was explained by the BE on panicles m^(–2),spikelets/panicle,spikelets m^(–2),and total dry weight.In the ratoon crop,the BE on grain yield was reduced to 60.9 and 27.6%with and without the contribution of the BE in the main crop,respectively.Consequently,55.1%of the BE on grain yield in the ratoon crop was contributed from the main crop.High stubble dry weight and non-structural carbohydrate(NSC)accumulation at the harvest of the main crop were responsible for the contribution of BE in the main crop to that in the ratoon crop.Our results suggest that increases in stubble dry weight and NSC accumulation at the harvest of the main crop could be important strategies for developing high-yielding cropping practices in the rice ratooning system.
基金supported by the National Natural Science Foundation of China(31971845 and 32101819)the earmarked fund for China Agriculture Research System(CARS-01-20)the China Postdoctoral Science Foundation(2021M691179)。
文摘Nitrogen(N) and seeding rates are important factors affecting grain yield and N use efficiency(NUE) in directseeded rice. However, these factors have not been adequately investigated on direct-seeded and double-season rice(DDR) in Central China. The objective of this study was to evaluate the effects of various N and seeding rates on the grain yield and NUE of an ultrashort-duration variety grown under DDR. Field experiments were conducted in 2018 in Wuxue County and 2019 in Qichun County, Hubei Province, China with four N rates and three seeding rates.The results showed that the grain yield of the ultrashort-duration variety ranged from 6.32 to 8.23 t ha–1with a total growth duration of 85 to 97 days across all treatments with N application. Grain yield was increased significantly by N application in most cases, but seeding rate had an inconsistent effect on grain yield. Furthermore, the response of grain yield to the N rates was much higher than the response to seeding rates. The moderate N rates of 100–150 and 70–120 kg N ha–1in the early and late seasons, respectively, could fully express the yield potential of the ultrashort-duration variety grown under DDR. Remarkably higher N responses and agronomic NUE levels were achieved in the early-season rice compared with the late-season rice due to the difference in indigenous soil N supply capacity(INS) between the two seasons. Seasonal differences in INS and N response should be considered when crop management practices are optimized for achieving high grain yield and NUE in ultrashort-duration variety grown under DDR.
文摘软件定义网络(Software Defined Network,SDN)是实现网络智能化的基础与主要技术途径。当前,商用的SDN网络一般应用于数据中心与软件定义广域网(Software-Defined WAN,SD-WAN)场景,其协议设计着眼于宽带、有线、固定的使用环境,普遍存在网络开销大,无法适应动态组网,很难应用于窄带、弱连接的战术边缘场景。基于此,文中在主流商用SDN协议的基础上,从控制平面自动构建、轻量化协议设计与业务流量调度等方面设计了一套面向战术边缘应用的、轻量化的SDN网络控制平面接口协议,仿真验证了所提方案的优越性。文中的研究可为智能化战术信息网络的设计提供一定的参考。
