Paddy field is an important land use in subtropical China. Development of high soil fertility and productivity is the management goal of paddy field, Fertilization and management practices have not only influenced the...Paddy field is an important land use in subtropical China. Development of high soil fertility and productivity is the management goal of paddy field, Fertilization and management practices have not only influenced the status of organic matter and nutrients in the soil but also affected the environmental quality. This article investigates the contents of organic carbon and the nutrients, and the change over the last 20 years in highly productive paddy soils and their environmental application. Field soils were sampled and the analytical results were compared with the corresponding values in the Second Soil Survey in Yujiang County of Jiangxi Province, China. The results showed that surface soils at a depth of 0-10 cm in highly productive paddy fields in Yujiang County of Jiangxi Province had contents of organic carbon （20.2 ±3.88） g kg^-1, total nitrogen （2.09±0.55） g kg^-1, and available phosphorus （42.7 ±32.7） mg kg^-1, respectively, which were all at very rich levels. Over the last 20 years, the organic carbon pool of the highly productive paddy soils reached a steady state. Total N and available P significantly increased, whereas available K changed a little. The amount and percentage of P immobilization in the surface soil （0-10 cm） of highly productive paddy fields were （142.7 ~ 41.1） mg kg-~ and （36.2~ 10.4）% of added P, and CEC （7.93 ~ 1.32） cmol kg-~. These two parameters were not higher than the mean values of paddy soils and upland red soils in the areas. Results also showed that fertilizer P in highly productive paddy soils had a high mobility and was prone to move toward a water body, which is the main source of nutrients causing eutrophication. Because of a weak K-fixing capacity, the available K content was not high in highly productive paddy soils. This suggests that attention should be paid to the K balance and the increase of soil K pool.展开更多
Based on the data at 29 monitoring sites in the whole basin of the Yujiang River and the Xunjiang River in Guigang City during 2014-2021,the single-factor evaluation method and the modified Nemerow pollution index met...Based on the data at 29 monitoring sites in the whole basin of the Yujiang River and the Xunjiang River in Guigang City during 2014-2021,the single-factor evaluation method and the modified Nemerow pollution index method were used to analyze temporal and spatial distribution characteristics of water quality in the Yujiang River and the Xunjiang River basins.The results showed that the Wusi River(the Yujiang River)and the Dahuang River(the Xunjiang River)had the best water quality,while water quality of the Duchong River(the Yujiang River)was the worst,and the proportion of inferior to class V reached 93%.The second was the Shepo River(the Xunjiang River),and the proportions of inferior to class V and below class IV were 21%and 64%.Comprehensive Nemerow pollution index was used to evaluate the water quality of the Yujiang River and the Xunjiang River during 2014-2021.Five tributary sections with worse water quality were the Duchong River,Xiajiangkou,the Chencun River,the Liyu River,and the Dongtang River,and NH3-N and TP exceeded the standard seriously.Among them,water quality of the Duchong River was the worst and was slightly improved during 2018-2021,but it still exceeded the standard seriously.The analysis showed that the main source of serious eutrophication in the basin was the increase of NH3-N and TP concentrations caused by agricultural non-point source emissions.展开更多
Flooding is the most frequent disaster in China. It affects people＇s lives and properties, causing considerable economic loss. Flood forecast and operation of reservoirs are important in flood emergency management. A...Flooding is the most frequent disaster in China. It affects people＇s lives and properties, causing considerable economic loss. Flood forecast and operation of reservoirs are important in flood emergency management. Although great progress has been achieved in flood forecast and reservoir operation through using computer, network technology, and geographic information system technology in China, the prediction accuracy of models are not satisfactory due to the unavailability of real-time monitoring data. Also, real-time flood control scenario analysis is not effective in many regions and can seldom provide online decision support function. In this research, a decision support system for real-time flood forecasting in Yujiang River Basin, South China （DSS-YRB） is introduced in this paper. This system is based on hydrological and hydraulic mathematical models. The conceptual framework and detailed components of the proposed DSS-YRB is illustrated, which employs real-time rainfall data conversion, model-driven hydrologic forecasting, model calibration, data assimilation methods, and reservoir operational scenario analysis. Multi-tiered architecture offers great flexibility, portability, reusability, and relia- bility. The applied case study results show the development and application of a decision support system for realtime flood forecasting and operation is beneficial for flood control.展开更多
基金supported by the National Natural Science Foundation of China(40471066)the Knowledge Innovation Program of the Chinese Academy of Sciences(KZCX1-SW-01-05).
文摘Paddy field is an important land use in subtropical China. Development of high soil fertility and productivity is the management goal of paddy field, Fertilization and management practices have not only influenced the status of organic matter and nutrients in the soil but also affected the environmental quality. This article investigates the contents of organic carbon and the nutrients, and the change over the last 20 years in highly productive paddy soils and their environmental application. Field soils were sampled and the analytical results were compared with the corresponding values in the Second Soil Survey in Yujiang County of Jiangxi Province, China. The results showed that surface soils at a depth of 0-10 cm in highly productive paddy fields in Yujiang County of Jiangxi Province had contents of organic carbon （20.2 ±3.88） g kg^-1, total nitrogen （2.09±0.55） g kg^-1, and available phosphorus （42.7 ±32.7） mg kg^-1, respectively, which were all at very rich levels. Over the last 20 years, the organic carbon pool of the highly productive paddy soils reached a steady state. Total N and available P significantly increased, whereas available K changed a little. The amount and percentage of P immobilization in the surface soil （0-10 cm） of highly productive paddy fields were （142.7 ~ 41.1） mg kg-~ and （36.2~ 10.4）% of added P, and CEC （7.93 ~ 1.32） cmol kg-~. These two parameters were not higher than the mean values of paddy soils and upland red soils in the areas. Results also showed that fertilizer P in highly productive paddy soils had a high mobility and was prone to move toward a water body, which is the main source of nutrients causing eutrophication. Because of a weak K-fixing capacity, the available K content was not high in highly productive paddy soils. This suggests that attention should be paid to the K balance and the increase of soil K pool.
基金Supported by Young and Middle-aged Teachers’Basic Scientific Research Ability Improvement Project in Guangxi Colleges and Universities(2021KY1970)。
文摘Based on the data at 29 monitoring sites in the whole basin of the Yujiang River and the Xunjiang River in Guigang City during 2014-2021,the single-factor evaluation method and the modified Nemerow pollution index method were used to analyze temporal and spatial distribution characteristics of water quality in the Yujiang River and the Xunjiang River basins.The results showed that the Wusi River(the Yujiang River)and the Dahuang River(the Xunjiang River)had the best water quality,while water quality of the Duchong River(the Yujiang River)was the worst,and the proportion of inferior to class V reached 93%.The second was the Shepo River(the Xunjiang River),and the proportions of inferior to class V and below class IV were 21%and 64%.Comprehensive Nemerow pollution index was used to evaluate the water quality of the Yujiang River and the Xunjiang River during 2014-2021.Five tributary sections with worse water quality were the Duchong River,Xiajiangkou,the Chencun River,the Liyu River,and the Dongtang River,and NH3-N and TP exceeded the standard seriously.Among them,water quality of the Duchong River was the worst and was slightly improved during 2018-2021,but it still exceeded the standard seriously.The analysis showed that the main source of serious eutrophication in the basin was the increase of NH3-N and TP concentrations caused by agricultural non-point source emissions.
基金Acknowledgements This research was supported by the special fund of State Key Lab of Water Environment Simulation （11Z01ESPCN）, and the Science Foundation of China University of Petroleum, Beijing （JCXK-2011- 05 and KYJJ2012-01-33）. Also, the authors would like to extend special appreciation to the anonymous reviewers and the editor for their constructive comments and suggestions that are extremely helpful in improving this paper.
文摘Flooding is the most frequent disaster in China. It affects people＇s lives and properties, causing considerable economic loss. Flood forecast and operation of reservoirs are important in flood emergency management. Although great progress has been achieved in flood forecast and reservoir operation through using computer, network technology, and geographic information system technology in China, the prediction accuracy of models are not satisfactory due to the unavailability of real-time monitoring data. Also, real-time flood control scenario analysis is not effective in many regions and can seldom provide online decision support function. In this research, a decision support system for real-time flood forecasting in Yujiang River Basin, South China （DSS-YRB） is introduced in this paper. This system is based on hydrological and hydraulic mathematical models. The conceptual framework and detailed components of the proposed DSS-YRB is illustrated, which employs real-time rainfall data conversion, model-driven hydrologic forecasting, model calibration, data assimilation methods, and reservoir operational scenario analysis. Multi-tiered architecture offers great flexibility, portability, reusability, and relia- bility. The applied case study results show the development and application of a decision support system for realtime flood forecasting and operation is beneficial for flood control.
