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Effects of long-term full straw return on yield and potassium response in wheat-maize rotation

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Journal of Integrative Agriculture 2015年第12期14卷 2467-2476页

作者： BAI You-lu WANG Lei LU Yan-li YANG Li-ping ZHOU Li-ping NI Lu CHENG Ming-fang institute of Agricultural {1. and Regional planning Chinese Academy of Agricultural Sciences

The effect of long-term straw return on crop yield, soil potassium（K） content, soil organic matter, and crop response to K from both straw and chemical K fertilizer（K_2SO_4） were investigated in a fixed site field experiment for winter wheat-summer maize rotation in 6 years for 1. seasons. The field experiment was located in northern part of North China Plain with a sandy soil in relatively low yield potential. Two factors, straw return and chemical K fertilizer, were studied with two levels in each factor. Field split design was employed, with two straw treatments, full straw return of previous crop（St） and no straw return, in main plots, and two chemical K fertilizer treatments, 0 and 60 kg K2 O ha^（–1., as sub-plots. The results showed that straw return significantly increased yields of winter wheat and summer maize by 1..5 and 1..2% in average, respectively, and the positive effect of straw return to crop yield showed more effective in lower yield season. Straw return significantly increased K absorption by the crops, with significant increase in straw part. In treatment with straw return, the K content in crop straw increased by 1..9 and 21.8% in wheat and maize, respectively, compared with no straw return treatment. But, straw return had little effect on K content in grain of the crops. Straw return had significant influences on total K uptake by wheat and maize plants, with an increase of 32.7 and 30.9%, respectively. There was a significant correlation between crop yield and K uptake by the plant. To produce 1.0 kg grain, the wheat and maize plants absorbed 3.26 and 2.24 kg K2 O, respectively. The contents of soil available K and soil organic matter were significantly affected by the straw return with an increase of 6.07 and 23.0%, respectively, compared to no straw return treatment. K_2SO_4 application in rate of 60 kg K2 O ha^（–1. showed no significant effect on wheat and maize yield, K content in crop straw, total K uptake by the crops, soil available K c

关键词： straw return potassium in straw wheat maize potassium response

Identification of homogeneous regions in the Pearl River Delta using a physically-based approach

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Identification of homogeneous regions in the Pearl River Del...

Chemical weathering and chemical runoffs in the seashore granite hills in South China

中国水利学会2021.术年会

作者：唐亦汉 Xue-zhi Tan Pei-yi Li Cheng-jia Su Xiao-hong Chen Guangdong Research institute of {1. resources and hydropower School of Civil Engineering Sun Yat-sen University Guangdong hydropower {1. and design institute

The increasing risk of flood in deltas calls for more reliable estimates of design flood levels. Applying a unified probability density function（PDF） for a whole delta area ignores the hydrodynamic diversity, and flood zones, where the flood level distributions in different spots are identical, need to be defined. A methodology to define flood zones, which considers the physical features of flood, has been proposed and applied in the Pearl River Delta（PRD）, Southern China. Results show that the flood zones defined solely according to the statistical characteristics are inapplicable for the spots that share similar statistical features but different driving forces of flood generation, es-pecially in spots where the river network density is high and unevenly distributed. The methodology proposed can solve this problem. Three flood zones are detected in the PRD area: Zone A is over 60 km away from the delta out-lets;Zone B is between 25 km and 60 km and Zone C is within 25 km towards the delta outlets. If one unified PDF is applied in the whole PRD, the overestimation of a 1.0-year design flood level Zone A can reach up to 0. 77 m. This research presents a sample to identify flood zones in a delta where the river network density is high, and the floods are induced by the interaction of river floods and tides.

关键词： Flood zone physical features design flood level estimation dense river network Pearl River Delta

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Science China Earth Sciences 2010年第8期53卷 1195-1204页

作者： GAO QuanZhou & TAO Zhen School of Geography and planning, Sun Yat-sen University, Guangzhou 51.275, China 1. School of Geography and planning Sun Yat-sen University Guangzhou 510275 China

Surface runoffs and the contents of major ions and dissolved silicon were surveyed and analyzed based on weekly sampling for one year in a granite watershed of Zhuhai City, Guangdong Province. The results demonstrated that the slope runoff played an essential role in feeding the rivulet during precipitation, whereas the groundwater was more important for the rivulet in the non-raining stages. Dissolved silicon, Na+, HCO3-, and Clions constituted the major chemical components of the rivulet water. Atmospheric CO2 and H2SO4 sourced from the oxidation of pyrite were the main erosive mediums in the natural chemical weathering. Natural chemical weathering, the wet and dry deposition of sea-salt, and acids precipitation contributed approximately equal shares of anions to the rivulet water. The ratio of NO3- to SO42- was more than 1.0 in the runoff of the studied seashore watershed, whereas it is less than 1.0 in the Xijiang River that is adjacent to the study area. This implied that the chemical composition of runoff is controlled mainly by the differences in atmospheric acid precipitation caused by human activities and lithology within the catchments under the same bio-climate zone. The CO2 flux consumed by the rock chemical weathering processes within the seashore granite watershed in South China was (0.35-1.37)×1.5 mol km-2 a-1.

关键词： chemical weathering granite ion sea-salt acid deposition CO2

Effects of rural domestic sewage reclaimed irrigation and regulation on heavy metals,PPCPs,water and nitrogen utilization,and microbial diversity in paddy field

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International Journal of Agricultural and Biological Engineering 2023年第4期16卷 245-256页

作者： Shizong Zheng Menghua Xiao Lei Wang Yuanyuan Li Wanchuan Xiao Dan Xu Jiafang Cai Rural water Conservancy Research {1. Zhejiang Institute of Hydraulics and EstuaryHangzhou 310020China Zhejiang institute of Marine {1. and design Hangzhou 310020China School of water Conservancy North China University of Water Resource and Electric PowerZhengzhou 450045China

Rural domestic reclaimed water(RDRW)is rural domestic sewage that being safely treated,the irrigation and reuse of RDRW are an effective way to alleviate the contradiction between supply and demand of water resources in South *** this study,four kinds of irrigation water sources(primary and secondary treated water R1.and R2,purified water R3 and river water CK)and three kinds of water level regulations(low,medium,and high field water level control of W1.W2 and W3)were set to study the impact of RDRW on soil and crop safety,water and nitrogen utilization and biodiversity for establishing the regulation mechanism of RDRW irrigation with field experiment,and monitoring was carried out in RDRW irrigation demonstration area to assess the effectiveness of *** results showed that,under RDRW irrigation,the contents of Cd and Pb increased slightly,while the contents of Cr,Cu and Zn decreased in paddy *** heavy metals content decreased along the direction of stem,leaf and grain in rice plants,but did not increase significantly in rice *** the increase of field water level,pharmaceutical and personal care products(PPCPs)content in 60-80 cm soil layer was accumulated,and the PPCPs content in rice husks was higher than that in grains,but it was at a very low *** to CK,RDRW irrigation can effectively increase rice yield,rainwater use efficiency(RUE)and nitrogen use efficiency(NUE)by 5.4%-7.6%,6.7%-9.4%and 21.7%-24.2%,respectively,and the species diversity,community diversity and richness in rice fields were ***,water level regulation of W3 with R2 water resource irrigation was conducive to the exertion of comprehensive *** monitoring of demonstration area showed that the consumption of fresh water was reduced by 530 mm,yield was increased by 9.6%,and the soil and crop were both ***-term irrigation of RDRW did not cause soil and crops pollution,however,it is still necessary to track and monitor the effect of the

关键词： reclaimed water irrigation heavy metals pharmaceutical and personal care products water and nitrogen use efficiency soil microbial diversity technique for order preference by similarity to an ideal solution

Accurate estimation of soil shear strength parameters

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Journal of Central South University 2019年第4期26卷 1000-1010页

作者： CHEN Li-hong LI Xu XU Yao CHEN Zu-yu DENG Gang Department of Civil Engineering Beijing Jiaotong University China institute of {1. resources and hydropower Research

The cost and safety of geotechnical engineering are highly depending on the accuracy of soil shear strength *** are three methods often used to estimate soil shear strength parameters,i.e.,moment method,3-sigma rule and linear regression *** this study,the accuracy of these three methods is *** linear regression method(LRM)can only offer the mean of shear strength *** engineers misuse the standard error of shear strength indexes as the standard *** misuse may highly underestimate the uncertainty and induce high risk to the geotechnical design.A modified LRM is proposed to determine both the mean and variance of shear strength *** moment method,three-sigma rule and LRM are used to analyze the tri-axial test data in Xiaolangdi Hydraulic Project and three numerical shear strength *** results demonstrate that:1.The modified LRM can offer the most accurate estimation to shear strength parameters;2)A dimensionless formula is much preferred in LRM rather than a dimensional *** stress ratio formula is much better than stress relation in the shear strength parameter *** proposed method is applicable to shear strength parameter analysis for tri-axial test data,direct shear test and the un-drained shear strength test of stratified clay.

关键词： linear regression method shear strength index tri-axial test reliability analysis data analysis uncertainty

Effects of water and nitrogen conditions under surge-root irrigation on growth and yield of apple trees

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排灌机械工程学报 2023年第2期41卷 179-186页

作者： YIN Yongle FEI Liangjun LI Zhe LIU Teng LI Zhongjie HAO Kun PENG Youliang institute of {1. resources and Hydroelectric Engineering Xi′an University of TechnologyXi′anShaanxi 710048China Shaanxi Provincial Land Engineering Construction Group Land Survey Planning and Design InstituteXi′anShaanxi 710064China Rural Revitalization planning and Development Guidance Center of Yulin YulinShaanxi 719000China

In order to explore the effects of different irrigation and nitrogen application on growth cha-racteristics and yield of apple trees under surge-root irrigation in mountainous areas of northern Shaanxi, field experiments were carried out with different apple trees. Three irrigation levels were applied: 85%-1.0%(H1., 70%-85%(H2) and 55%-70%(H3) of the field water capacity, respectively, and three nitrogen levels were N1.360 g/plant), N2(240 g/plant) and N3(1.0 g/plant). The results show that irrigation and nitrogen application has significant effects on new shoot length, flowering and fruit setting, fruit diameter, fruit volume and yield of apple. The leaf area index(LAI) shows a single trend during the growth period, and the peak value appears in the middle of July. Under the same irrigation level, compared with N3, N1.increases in yield, new shoot length, LAI, transverse diameter, longitudinal diameter, volume, flowering and fruit setting by 1..91., 28.31., 1..75%, 1..38%, 1..1.%, 36.60%, 20.92% and 5.1.%, respectively, while N2 also increases by 1..40%, 1..63%, 4.86%, 5.40%, 5.1.%, 1..01., 26.1.% and 1..74%, respectively. The rate of flowering and fruit setting decreases with the increase of nitrogen application. Under the same nitrogen level, compared with H3, H1.increases in yield, new shoot length, LAI, transverse diameter, longitudinal diameter, volume, flowering and fruit setting by 34.65%, 1..49%, 30.77%, 3.93%, 4.95%, 1..86%, 33.1.% and 28.62%, respectively, while H2 also increases by 33.67%, 1..42%, 67.52%, 3.81., 2.97%, 1..57%, 43.45% and 27.26%, respectively. The rate of flowering and fruit setting decreases first and then increases with the increase of irrigation amount. Compared with H3N3, the yield of other treatments increases by 2.69%-52.20%, while H2N1.treatment has the highest yield(26 852.55 kg/ha). Considering from the point of view of promoting growth and increasing yield, the best water and nitrogen combination mode of mountain apple in northe

关键词： mountain apple surge-root irrigation irrigation nitrogen growth yield

Research on Railway Real-time Online Power Supply Automation Network Communication System

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Research on Railway Real-time Online Power Supply Automation...

Projection of China’s future runoff based on the CMIP6 mid-high warming scenarios

作者： Li Liu Wei Liu Kaiqin Peng Wuhan Railway Vocational College of Technology Hubei Provincial water {1. and hydropower planning Survey and design institute

Railway construction has entered a stage of rapid *** design and construction of high-speed railways are further *** the face of competition from advanced technologies,it is very urgent to study the real-time online power supply automation system for *** the same time,network communication problems have become a core issue in the research and development of traction power supply automation *** this paper,the communication system is *** high-speed railway runs at high speed,the train time interval is short,and the maintenance time is *** the premise of considering the safe and reliable operation of the system,the whole data of TPSAS is re-planned according to the principle of management and control diversion *** solution for industrial Ethernet of traction substation is proposed,which is distributed switching double-loop fiber self-healing *** shows that TSAS adopts distributed-switched double-loop fiber self-healing Ethernet,which is a better choice for railway network communication systems.

关键词： Railway Power supply automation Industrial ethernet Communication real-time

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Science China Earth Sciences 2023年第3期66卷 528-546页

作者： Jiayue ZHOU Hui LU Kun YANG Ruijie JIANG Yuan YANG Wei WANG Xuejun ZHANG Department of Earth System Science Ministry of Education Key Laboratory of Earth System ModelingInstitute for Global Change StudiesTsinghua UniversityBeijing 100084China National Tibetan Plateau Data Center State Key Laboratory of Tibetan Plateau Earth System and Resource EnvironmentInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Center for Western Weather and water Extremes Scripps Institution of OceanographyUniversity of California San DiegoSan Diego 92037USA Changjiang institute of Survey PlanningDesign and ResearchWuhan 430010China State Key Laboratory of Simulation and Regulation of water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China Research Center on Flood and Drought Disaster Reduction of the Ministry of water {1. Beijing 100038China

The latest Coupled Model Intercomparison Project Phase 6(CMIP6)proposes new shared pathways(SSPs)that incorporate socioeconomic development with more comprehensive and scientific experimental designs;however,few studies have been performed on the projection of future multibasin hydrological changes in China based on CMIP6 *** this paper,we use the Equidistant Cumulative Distribution Function method(EDCDFm)to perform downscaling and bias correction in daily precipitation,daily maximum temperature,and daily minimum temperature for six CMIP6 models based on the historical gridded data from the high-resolution China Meteorological Forcing Dataset(CMFD).We use the bias-corrected precipitation,temperature,and daily mean wind speed to drive the variable infiltration capacity(VIC)hydrological model,and study the changes in multiyear average annual precipitation,annual evapotranspiration and total annual runoff depth relative to the historical baseline period(1.85–201.)for the Chinese mainland,basins and grid scales in the 21.t century future under the SSP2-4.5 and SSP5-8.5 *** study shows that the VIC model accurately simulates runoff in major Chinese basins;the model data accuracy improves substantially after downscaling bias correction;and the future multimodel-mean multiyear average annual precipitation,annual evapotranspiration,and total annual runoff depth for the Chinese mainland and each basin increase relative to the historical period in near future(2020–2049)and far future(2070–2099)under the SSP2-4.5 and *** new CMIP6-based results of this paper can provide a strong reference for extreme event prevention,{1. resource utilization and management in China in the 21.t century.

关键词： CMIP6 VIC model EDCDFm Chinese basins Future hydrological changes

Cascading dam breach process simulation using a coupled modeling platform

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Science China(Technological Sciences) 2019年第8期62卷 1455-1466页

作者： LIU ZhiPing GUO XinLei ZHOU XingBo FU Hui XIA QingFu LI ShaoJun State Key Laboratory of Simulation and Regulation of water Cycle in River Basin China Institute of Water Resources and Hydropower Research Beijing 100038 China China Renewable Energy Engineering institute Beijing 100120 China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China

This study evaluates the possibility of a cascade failure by developing a coupled breach-modeling platform based on onedimensional flow modeling of the river channel, flood propagation, regulation process of reservoir fluctuation, overtopping with breaching, and wave damping downstream. A hyperbolic model of the DB-IWHR was embedded into the platform to simulate the dam breaching process. Five breach models and software were used to calculate the Tangjiashan barrier lake breaching. The results of a sensitivity study were then compared with the measured data. The peak flow and the time of occurrence were confirmed to be predictable with a reasonable accuracy if the input values were within ranges appropriate for the model. The approach was applied to a case involving two layout planning schemes for a cascade of rock-filled dams under extreme operating conditions. The probability of the failure of a key control cascade downstream caused by a continuous cascade breach upstream was simulated. Moreover, measures to prevent the transmission of risk by advance warnings were investigated. The proposed methodology and the discharge capacity measures provide guidelines to assess the risk to a cascade of dams under extreme operating conditions and offer support for the {1. criteria of unusual discharge structures for very large dams.

关键词： cascades dam breach extreme operating condition sensitivity analysis flood discharge structure