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An optimized strategy of nitrogen-split application based on the leaf positional differences in chlorophyll meter readings

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Journal of Integrative Agriculture 2024年第8期23卷 2605-2617页

作者： gaozhao wu Xingyu Chen Yuguang Zang Ying Ye Xiaoqing Qian Weiyang Zhang Hao Zhang Lijun Liu Zujian Zhang Zhiqin Wang Junfei Gu Jianchang Yang Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Cultivation and Physiology/Agricultural College Yangzhou UniversityYangzhou 225009China Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops Yangzhou UniversityYangzhou 225009China Key Laboratory of Arable Land Quality Monitoring and Evaluation Ministry of Agriculture and Rural AffairsYangzhou UniversityYangzhou 225127China

Modern rice production faces the dual challenges of increasing grain yields while reducing inputs of chemical ***,the disequilibrium between the nitrogen(N)supplement from the soil and the demand for N of plants is a serious obstacle to achieving these ***-based diagnosis can help farmers make better choices regarding the timing and amount of topdressing N *** objective was to evaluate a non-destructive assessment of rice N demands based on the relative SPAD value(RSPAD)due to leaf positional *** this study,two field experiments were conducted,including a field experiment of different N rates(Exp.I)and an experiment to evaluate the new strategy of nitrogen-split application based on RSPAD(***).The results showed that higher N inputs significantly increased grain yield in modern high yielding super rice,but at the expense of lower nitrogen use efficiency(NUE).The N nutrition index(NNI)can adequately differentiate situations of excessive,optimal,and insufficient N nutrition in rice,and the optimal N rate for modern high yielding rice is higher than conventional *** RSPAD is calculated as the SPAD value of the top fully expanded leaf *** value of the third leaf,which takes into account the non-uniform N distribution within a *** RSPAD can be used as an indicator for higher yield and NUE,and guide better management of N fertilizer ***,we developed a new strategy of nitrogen-split application based on RSPAD,in which the N rate was reduced by 18.7%,yield was increased by 1.7%,and the agronomic N use efficiency was increased by 27.8%,when compared with standard farmers'*** strategy of N fertilization shows great potential for ensuring high yielding and improving NUE at lower N inputs.

关键词： canopy crop management practices nitrogen nitrogen nutrition index rice SPAD

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Irrigation regimes modulate non-structural carbohydrate remobilization and improve grain filling in rice(Oryza sativa L.)by regulating starch metabolism

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Journal of Integrative Agriculture 2024年第5期23卷 1507-1522页

作者： Yuguang Zang gaozhao wu Qiangqiang Li Yiwen Xu Mingming Xue Xingyu Chen Haiyan Wei Weiyang Zhang Hao Zhang Lijun Liu Zhiqin Wang Junfei Gu Jianchang Yang Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Cultivation and Physiology/Agricultural College YangzhouUniversityYangzhou225009China Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops Yangzhou UniversityYangzhou 225009China

Recently developed ‘super’ rice cultivars with greater yield potentials often suffer from the problem of poor grain filling, especially in inferior spikelets. Here, we studied the activities of enzymes related to starch metabolism in rice stems and grains, and the microstructures related to carbohydrate accumulation and transportation to investigate the effects of different water regimes on grain filling. Two ‘super’ rice cultivars were grown under two irrigation regimes of well-watered(WW) and alternate wetting and moderate soil drying(AWMD). Compared with the WW treatment,the activities of ADP glucose pyrophosphorylase(AGPase), starch synthase(StSase) and starch branching enzyme(SBE), and the accumulation of non-structural carbohydrates(NSCs) in the stems before heading were significantly improved, and more starch granules were stored in the stems in the AWMD treatment. After heading, the activities of α-amylase, β-amylase, sucrose phosphate synthase(SPS) and sucrose synthase in the synthetic direction(SSs)were increased in the stems to promote the remobilization of NSCs for grain filling under AWMD. During grain filling, the enzymatic activities of sucrose synthase in the cleavage direction(SSc), AGPase, StSase and SBE in the inferior spikelets were increased, which promoted grain filling, especially for the inferior spikelets under ***, there were no significant differences in vascular microstructures. The grain yield and grain weight could be improved by 13.1 and 7.5%, respectively, by optimizing of the irrigation regime. We concluded that the low activities of key enzymes in carbon metabolism is the key limitation for the poor grain filling, as opposed to the vascular microstructures, and AWMD can increase the amount of NSC accumulation in the stems before heading, improve the utilization rate of NSCs after heading, and increase the grain filling, especially in the inferior spikelets, by altering the activities of key enzymes in carbon metabolism.

关键词： rice(Oryza sativa L.) non-structural carbohydrates(NsCs) enzymatic activity grain illing starch granules vascular bundle

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换流站电磁噪声的计算机仿真模型

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武汉大学学报（工学版） 2010年第2期43卷 261-264,268页

作者：张小武吕金壮邬雄万保权武汉大学计算机学院湖北武汉430072 国网电力科学研究院湖北武汉430074 中国南方电网技术研究中心广东广州510620

高压直流换流站中的换流阀在运行过程中会产生高强度电磁噪声,在30-500 kHz频段对邻近的载波通讯系统形成潜在干扰.为预测该电磁噪声水平,以高肇直流系统载波频段噪声水平的实测结果为基础,建立了符合换流站实际运行参数和一次设备高频... 详细信息

高压直流换流站中的换流阀在运行过程中会产生高强度电磁噪声,在30-500 kHz频段对邻近的载波通讯系统形成潜在干扰.为预测该电磁噪声水平,以高肇直流系统载波频段噪声水平的实测结果为基础,建立了符合换流站实际运行参数和一次设备高频参数的仿真模型,通过对肇庆换流站的电磁噪声实测值与仿真计算结果的比较证明了模型的有效性.

关键词：换流站电磁噪声传导模型

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高肇直流工程直流滤波器C1不平衡保护分析及改进措施

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水电能源科学 2015年第12期33卷 181-184,164页

作者：邬乾晋杨光源张楠郑伟周全中国南方电网超高压输电公司检修试验中心广东广州510663

为解决高肇直流工程直流滤波器C1不平衡保护发生的多次误动事件、提高保护的正确动作可靠性,从高肇直流过程C1高压电容的接线形式、电容器的内部结构入手,分析了直流滤波器C1不平衡保护的原理,结合不平衡保护原理和保护误动后的故障录波... 详细信息

为解决高肇直流工程直流滤波器C1不平衡保护发生的多次误动事件、提高保护的正确动作可靠性,从高肇直流过程C1高压电容的接线形式、电容器的内部结构入手,分析了直流滤波器C1不平衡保护的原理,结合不平衡保护原理和保护误动后的故障录波,发现基于积分特性的保护判据从原理上不能躲开采集电流上下跳变的干扰,提出了基于非积分特性的保护逻辑改进措施,并利用RTDS数字仿真系统做了故障录波回放和故障仿真试验。试验结果表明,改进后的保护逻辑能有效避免测量干扰导致的保护误动。

关键词：高肇直流直流滤波器 C1不平衡保护 RTDS数字仿真系统

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