Based on ASP.NET,a orange fruit tree fertilizer expert system software was developed.The system could simulate and decide an annual fertilization plan for young and mature trees in terms of geographical position and c...Based on ASP.NET,a orange fruit tree fertilizer expert system software was developed.The system could simulate and decide an annual fertilization plan for young and mature trees in terms of geographical position and climate.This paper introduced the design conditions,framework,production,and deployment of the system.It exhibited characters of orange specialty and was a typical online agriculture expert system.The use of the system for orange fruit management could decrease production cost,guarantee orange quality and improve economical benefit at the same time.Farmer using the system saved N input by 41-238 g/plant,P2O5 input 3-24 g/plant,and K2O input 1-36 g/plant,and got higher yield by 6-17 kg/plant.展开更多
耕地资源是进行农业生产的核心,对耕地生态进行风险评价,能够为人类活动对生态系统的影响提供预测。基于文献大数据分析软件和文献查阅方法,从Web of Science(WOS)核心数据库和CNKI数据库中有条件地分别筛选出380篇和306篇文章,采用Cite...耕地资源是进行农业生产的核心,对耕地生态进行风险评价,能够为人类活动对生态系统的影响提供预测。基于文献大数据分析软件和文献查阅方法,从Web of Science(WOS)核心数据库和CNKI数据库中有条件地分别筛选出380篇和306篇文章,采用CiteSpace V软件对目标领域的主题、关键词和WOS分类进行共现分析,对耕地生态风险评价研究领域的知识演化路径、研究内容和热点进行详细评述,旨在为未来耕地生态风险评价研究提供参考。结果表明:国内耕地生态风险评价研究的热点词聚类结果集中反映为“生态安全”“重金属”“生态足迹”“社会价值”和“耕地保护”五大类;国外耕地生态风险评价研究的热点词聚类结果集中反映为“农业灌溉土地”“土壤退化”“地统计分析”和“土地利用”四大类。通过研究得到三个方面的结论:①国外关于耕地生态风险评价的研究主题比较零散,主要集中在对耕地土壤重金属的分析与评估;②国内耕地生态风险评价的研究在2015—2017年进入活跃期,研究主题的演化趋势具有一定的政策指向性;③国外的耕地生态风险评价研究与国内的研究在方向和尺度上有很大的差异,具有明显的区域差异性。展开更多
The Nu-Salween River(NSR),the longest free-flow river in Southeast Asia,plays an irreplaceable role in social development and ecological protection.The lower NSR region is particularly valuable as it is inhabited by a...The Nu-Salween River(NSR),the longest free-flow river in Southeast Asia,plays an irreplaceable role in social development and ecological protection.The lower NSR region is particularly valuable as it is inhabited by approximately 6.7 million people.The basin has limited hydraulic conservancy infrastructure and insufficient ability to cope with climate change risks.Studying the hydrological characteristics and changes in the basin provides the scientific basis for rational protection and development of the basin.However,owing to the limitation of observation data,previous studies have focused on the local area and neglected the study of the lower reaches,which is not enough to reflect the spatial characteristics of the entire basin.In this study,the ECMWF 5th generation reanalysis data(ERA5)and Multi-Source Weighted-Ensemble Precipitation(MSWEP)were applied to develop a geomorphology-based hydrological model(GBHM)for reconstructing hydrological datasets(i.e.GBHM-ERA5 and GBHM-MSWEP).The reconstructed datasets covering the complete basin were verified against the gauge observation and compared with other commonly used streamflow products,including Global Flood Awareness System v2.1,GloFAS-Reanalysis dataset v3.0,and linear optimal runoff aggregate(LORA).The comparison results revealed that GBHM-ERA5 is significantly better than the other four datasets and provides a good reproduction of the hydrological characteristics and trends of the NSR.Detailed analysis of GBHM-ERA5 revealed that:(1)A multi-year mean surface runoff represented 39%of precipitation over the basin during 1980–2018,which had low surface runoff in the upstream,while areas around the Three Parallel Rivers Area and the estuary had abundant surface runoff.(2)The surface runoff and discharge coefficient of variations in spring were larger than those in other seasons,and the inter-annual variation in the downstream was smaller than that in the upstream and midstream regions.(3)More than 70%of the basin areas showed a decreasing trend in the surface runoff,except for parts of Nagqu,south of Shan State in Myanmar,and Thailand,where surface runoff has an increasing trend.(4)The downstream discharge has dropped significantly at a rate of approximately 680 million cubic metresper year,and the decline rate is greater than that of upstream and midstream,especially in summer.This study provides a data basis for subsequent studies in the NSR basin and further elucidates the impact of climate change on the basin,which is beneficial to river planning and promotes international cooperation on the water-and eco-security of the basin.展开更多
基金fund by the Major Science and Technology Program (2009ZX07102-004),Chinathe IPNI (International Plant Nutrition Institute) Program,Canada (2009ZX07102-004)
文摘Based on ASP.NET,a orange fruit tree fertilizer expert system software was developed.The system could simulate and decide an annual fertilization plan for young and mature trees in terms of geographical position and climate.This paper introduced the design conditions,framework,production,and deployment of the system.It exhibited characters of orange specialty and was a typical online agriculture expert system.The use of the system for orange fruit management could decrease production cost,guarantee orange quality and improve economical benefit at the same time.Farmer using the system saved N input by 41-238 g/plant,P2O5 input 3-24 g/plant,and K2O input 1-36 g/plant,and got higher yield by 6-17 kg/plant.
文摘耕地资源是进行农业生产的核心,对耕地生态进行风险评价,能够为人类活动对生态系统的影响提供预测。基于文献大数据分析软件和文献查阅方法,从Web of Science(WOS)核心数据库和CNKI数据库中有条件地分别筛选出380篇和306篇文章,采用CiteSpace V软件对目标领域的主题、关键词和WOS分类进行共现分析,对耕地生态风险评价研究领域的知识演化路径、研究内容和热点进行详细评述,旨在为未来耕地生态风险评价研究提供参考。结果表明:国内耕地生态风险评价研究的热点词聚类结果集中反映为“生态安全”“重金属”“生态足迹”“社会价值”和“耕地保护”五大类;国外耕地生态风险评价研究的热点词聚类结果集中反映为“农业灌溉土地”“土壤退化”“地统计分析”和“土地利用”四大类。通过研究得到三个方面的结论:①国外关于耕地生态风险评价的研究主题比较零散,主要集中在对耕地土壤重金属的分析与评估;②国内耕地生态风险评价的研究在2015—2017年进入活跃期,研究主题的演化趋势具有一定的政策指向性;③国外的耕地生态风险评价研究与国内的研究在方向和尺度上有很大的差异,具有明显的区域差异性。
基金This work is jointly supported by the National Key Research and Development Program of China(2016YFA0601603)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0206)+1 种基金the National Natural Science Foundation of China(91747101&41801260)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA20100103).
文摘The Nu-Salween River(NSR),the longest free-flow river in Southeast Asia,plays an irreplaceable role in social development and ecological protection.The lower NSR region is particularly valuable as it is inhabited by approximately 6.7 million people.The basin has limited hydraulic conservancy infrastructure and insufficient ability to cope with climate change risks.Studying the hydrological characteristics and changes in the basin provides the scientific basis for rational protection and development of the basin.However,owing to the limitation of observation data,previous studies have focused on the local area and neglected the study of the lower reaches,which is not enough to reflect the spatial characteristics of the entire basin.In this study,the ECMWF 5th generation reanalysis data(ERA5)and Multi-Source Weighted-Ensemble Precipitation(MSWEP)were applied to develop a geomorphology-based hydrological model(GBHM)for reconstructing hydrological datasets(i.e.GBHM-ERA5 and GBHM-MSWEP).The reconstructed datasets covering the complete basin were verified against the gauge observation and compared with other commonly used streamflow products,including Global Flood Awareness System v2.1,GloFAS-Reanalysis dataset v3.0,and linear optimal runoff aggregate(LORA).The comparison results revealed that GBHM-ERA5 is significantly better than the other four datasets and provides a good reproduction of the hydrological characteristics and trends of the NSR.Detailed analysis of GBHM-ERA5 revealed that:(1)A multi-year mean surface runoff represented 39%of precipitation over the basin during 1980–2018,which had low surface runoff in the upstream,while areas around the Three Parallel Rivers Area and the estuary had abundant surface runoff.(2)The surface runoff and discharge coefficient of variations in spring were larger than those in other seasons,and the inter-annual variation in the downstream was smaller than that in the upstream and midstream regions.(3)More than 70%of the basin areas showed a decreasing trend in the surface runoff,except for parts of Nagqu,south of Shan State in Myanmar,and Thailand,where surface runoff has an increasing trend.(4)The downstream discharge has dropped significantly at a rate of approximately 680 million cubic metresper year,and the decline rate is greater than that of upstream and midstream,especially in summer.This study provides a data basis for subsequent studies in the NSR basin and further elucidates the impact of climate change on the basin,which is beneficial to river planning and promotes international cooperation on the water-and eco-security of the basin.
