Water and soil conservation is an important part of eco-civilization con-struction. It is a major part of eco-construction and lifeline of social and economy development. Therefore, water and soil conservation is of g...Water and soil conservation is an important part of eco-civilization con-struction. It is a major part of eco-construction and lifeline of social and economy development. Therefore, water and soil conservation is of great significance in maintaining eco-safety. The research concluded status quo and characters of water and soil losses in China and analyzed water and soil conservation and construction of eco-civilization from the perspectives of water and soil conservation and con-struction of eco-civilization.展开更多
A genomic DNA library was constructed to the elite rice cultivar “Minghui 63” using the cosmid SuperCos1 as the vector. The library consisted of 45000 clones with average insert size about 40 kb. It was estimated ...A genomic DNA library was constructed to the elite rice cultivar “Minghui 63” using the cosmid SuperCos1 as the vector. The library consisted of 45000 clones with average insert size about 40 kb. It was estimated that this library had a capacity of 4.2 times equivalent of the haploid genome of rice.展开更多
The authors assessed if wetlands can contribute to flood damage reduction in the Red River Basin, Minnesota, by providing reliable flood water storage. Hydrology and biodiversity in 28 natural and restored wetlands su...The authors assessed if wetlands can contribute to flood damage reduction in the Red River Basin, Minnesota, by providing reliable flood water storage. Hydrology and biodiversity in 28 natural and restored wetlands suggested uncontrolled natural wetlands provided the highest mean annual flood storage at 15 cm of runoff while single and 2-stage outlet controlled wetlands provided 3.0 and 8.1 cm of runoff control. Natural controlled wetlands, followed by 2-stage and single stage outlet controlled restorations provided 10.2, 6.6, and 2.2 cm of storage for early summer storm events. Two years of recorded water levels and a 20-year continuous meteorological record were used to model ＂temporary water level increases＂ in each wetland. Species diversity, hydrology, and watershed land use variables are inversely related where high quality and diverse wetlands had the lowest amplitude and frequency of water level increases, while low quality wetlands had the highest. Uncontrolled natural wetlands had the highest biological diversity and the lowest frequency and magnitude of temporary water levels increased. A significant biodiversity declines were measured where water level increases were greater than 2.7 meters. Strong multi-linear relationships between watershed land uses and watershed/wetland ratio explained wetland hydraulic performance and biodiversity relations （r2 ranging from 0.6-0.8）. Non-native wetland plant diversity increased with greater water level dynamics.展开更多
The tidal flat along the Changjiang(Yangtze) River estuary has long been reclaimed for the agricultural purposes, with the prevailing hydrological conditions during such pedogenic transformations being of great import...The tidal flat along the Changjiang(Yangtze) River estuary has long been reclaimed for the agricultural purposes, with the prevailing hydrological conditions during such pedogenic transformations being of great importance to their successful development. In this study, samples of surface sediment from Chongming Dongtan, situated at the mouth of the Changjiang River estuary, were collected and analyzed in order to understand how hydrological management can influence the concentrations of heavy metals and salt ions in pore water, and chemical fractionation of heavy metals during the reclamation process. We performed a series of experiments that simulated three dif ferent hydrological regimes: permanent flooding(R1), alternative five-day periods of wetting and drying(R2), continuous field capacity(R3). Our results exhibited good Pearson correlations coefficients between heavy metals and salt ions in the pore water for both R1 and R2. In particular, the concentrations of salt ions in the pore water decreased in all three regimes, but showed the biggest decline in R2. With this R2 experiment, the periodic concentration patterns in the pore water varied for Fe and Mn, but not for Cr, Cu, Pb and Zn. Neither the fractionation of Ni nor the residual fractions of any metals changed significantly in any regime. In R1, the reducible fractions of heavy metals(Cr, Cu, Zn and Pb) in the sediment decreased, while the acid extractable fractions increased. In R2, the acid extractable and the reducible fractions of Cr, Cu, Zn and Pb both decreased, as did the oxidizable fraction of Cu. These data suggest that an alternating hydrological regime can reduce both salinity and the availability of heavy metals in sediments.展开更多
Water is the source of all life, and is closely related to human civilization. It had a special significance in China, so the ancient Chinese created the dragon god as a symbol of China, the Chinese and Chinese civili...Water is the source of all life, and is closely related to human civilization. It had a special significance in China, so the ancient Chinese created the dragon god as a symbol of China, the Chinese and Chinese civilization. It can be said that the unique hydrological conditions on the territory of China created three great historical miracles： China, the Chinese people, and Chinese civilization. The Chinese have dedicated more effort than people in any other countries to water control and water use in order to make effective use of water resources and prevent flooding. It is their unparalleled achievements that have laid the foundation for these three miracles. Today, the Chinese people are facing unprecedented challenges in water control and water use. Exploring the historical Chinese relationship with water offers a good opportunity to understand the important role that water plays in long-term social development.展开更多
基金Supported by the Twelfth Five-year-plan in National Science and Technology for the Rural Development in China(2011BAD31B01)~~
文摘Water and soil conservation is an important part of eco-civilization con-struction. It is a major part of eco-construction and lifeline of social and economy development. Therefore, water and soil conservation is of great significance in maintaining eco-safety. The research concluded status quo and characters of water and soil losses in China and analyzed water and soil conservation and construction of eco-civilization from the perspectives of water and soil conservation and con-struction of eco-civilization.
文摘A genomic DNA library was constructed to the elite rice cultivar “Minghui 63” using the cosmid SuperCos1 as the vector. The library consisted of 45000 clones with average insert size about 40 kb. It was estimated that this library had a capacity of 4.2 times equivalent of the haploid genome of rice.
文摘The authors assessed if wetlands can contribute to flood damage reduction in the Red River Basin, Minnesota, by providing reliable flood water storage. Hydrology and biodiversity in 28 natural and restored wetlands suggested uncontrolled natural wetlands provided the highest mean annual flood storage at 15 cm of runoff while single and 2-stage outlet controlled wetlands provided 3.0 and 8.1 cm of runoff control. Natural controlled wetlands, followed by 2-stage and single stage outlet controlled restorations provided 10.2, 6.6, and 2.2 cm of storage for early summer storm events. Two years of recorded water levels and a 20-year continuous meteorological record were used to model ＂temporary water level increases＂ in each wetland. Species diversity, hydrology, and watershed land use variables are inversely related where high quality and diverse wetlands had the lowest amplitude and frequency of water level increases, while low quality wetlands had the highest. Uncontrolled natural wetlands had the highest biological diversity and the lowest frequency and magnitude of temporary water levels increased. A significant biodiversity declines were measured where water level increases were greater than 2.7 meters. Strong multi-linear relationships between watershed land uses and watershed/wetland ratio explained wetland hydraulic performance and biodiversity relations （r2 ranging from 0.6-0.8）. Non-native wetland plant diversity increased with greater water level dynamics.
基金Supported by the National Natural Science Foundation of China(Nos.41271466,41671461)
文摘The tidal flat along the Changjiang(Yangtze) River estuary has long been reclaimed for the agricultural purposes, with the prevailing hydrological conditions during such pedogenic transformations being of great importance to their successful development. In this study, samples of surface sediment from Chongming Dongtan, situated at the mouth of the Changjiang River estuary, were collected and analyzed in order to understand how hydrological management can influence the concentrations of heavy metals and salt ions in pore water, and chemical fractionation of heavy metals during the reclamation process. We performed a series of experiments that simulated three dif ferent hydrological regimes: permanent flooding(R1), alternative five-day periods of wetting and drying(R2), continuous field capacity(R3). Our results exhibited good Pearson correlations coefficients between heavy metals and salt ions in the pore water for both R1 and R2. In particular, the concentrations of salt ions in the pore water decreased in all three regimes, but showed the biggest decline in R2. With this R2 experiment, the periodic concentration patterns in the pore water varied for Fe and Mn, but not for Cr, Cu, Pb and Zn. Neither the fractionation of Ni nor the residual fractions of any metals changed significantly in any regime. In R1, the reducible fractions of heavy metals(Cr, Cu, Zn and Pb) in the sediment decreased, while the acid extractable fractions increased. In R2, the acid extractable and the reducible fractions of Cr, Cu, Zn and Pb both decreased, as did the oxidizable fraction of Cu. These data suggest that an alternating hydrological regime can reduce both salinity and the availability of heavy metals in sediments.
文摘Water is the source of all life, and is closely related to human civilization. It had a special significance in China, so the ancient Chinese created the dragon god as a symbol of China, the Chinese and Chinese civilization. It can be said that the unique hydrological conditions on the territory of China created three great historical miracles： China, the Chinese people, and Chinese civilization. The Chinese have dedicated more effort than people in any other countries to water control and water use in order to make effective use of water resources and prevent flooding. It is their unparalleled achievements that have laid the foundation for these three miracles. Today, the Chinese people are facing unprecedented challenges in water control and water use. Exploring the historical Chinese relationship with water offers a good opportunity to understand the important role that water plays in long-term social development.
