Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance o...Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance of water supply and demand in the region was established, and the security of water resource was assessed, from which the results that the effects of unified management of water resources in the Heihe River basin between Gansu Province and Inner Mongolia on regional hydrology are significant with a decrease in water supply diverted from Heihe River and an increase in groundwater extracted. In addition, it was found that the groundwater level has been steadily decreasing due to over pumping and decrease in recharges. In present year （2003）, the volume of potential groundwater in the irrigation districts is far small because of the groundwater overdraft; even in the particular regions, there is no availability of groundwater resources for use. By 2003, water supply is not sufficient to meet the water demand in the different irrigation districts, the sustainable development and utilization of water resources are not secured, and the water supply crisis occurs in Pingchuan irrigation district. Achieving water security for the sustainable development of society, agriculture, economy, industry, and livelihoods while maintaining or improving the abilities of the management and planning of water resources, determining of the reasonable percentage between water supply and groundwater utilization and water saving in agricultural irrigation are taken into account. If this does not occur, it is feared that the present performance of water development and planning may further aggravate the problem of scarcities of water resources and further damage the fragile ecological system.展开更多
This study addresses the adaptation of Nitraria sphaerocarpa to blown sand at the edge of a desert oasis with regard to the aspects of soil seed banks, seedlings, and population. Horizontally, the total number of seed...This study addresses the adaptation of Nitraria sphaerocarpa to blown sand at the edge of a desert oasis with regard to the aspects of soil seed banks, seedlings, and population. Horizontally, the total number of seeds per unit area decreased from the shrub canopy center to intershrub areas, and most seeds were found under shrub canopies. Vertically, the highest proportion of seeds was found at depths of 5-10 cm. The emergence percentage, seedling mass, and seedling height, which were significantly affected by both burial depth and seed size, were highest at the optimal burial depth of 2 cm, and decreased with increasing burial depth in each seed size-class. Although seedling mass was usually greatest for large seeds and least for small seeds at each burial depth, little difference was observed in seedling height at shallow burial depths of 0-3 cm. The population shows a patchy and discontinuous distribution pattern. Population height increases with increasing sand depth. Also the density increases with increasing depth of sand in the desert; however, there is a steady decrease when the depth of sand is more than 100 cm. This result indicates that the depth of sand that is most suitable for the growth of Nitraria sphaerocarpa is 100 cm. The size of the population is significantly correlated with the sand depth, which increases with increasing depth in the desert.展开更多
通过改变混合酸(盐酸-硝酸-氢氟酸-高氯酸)中高氯酸的比例,采用石墨管加热消解和电热板加热消解2种方式,残渣用逆王水提取,3%稀硝酸定容测定,建立了一种理想的酸分解方法用于电感耦合等离子体质谱/发射光谱法(ICP-MS/OES)测定地球化学...通过改变混合酸(盐酸-硝酸-氢氟酸-高氯酸)中高氯酸的比例,采用石墨管加热消解和电热板加热消解2种方式,残渣用逆王水提取,3%稀硝酸定容测定,建立了一种理想的酸分解方法用于电感耦合等离子体质谱/发射光谱法(ICP-MS/OES)测定地球化学样品主、次、痕量元素。结果表明,当使用10 mL逆王水、5 m L氢氟酸、石墨管加热消解(加入2~3 mL高氯酸),或电热板加热消解(加入3~4 mL高氯酸分解试样),使用10 mL 50%逆王水提取,对主、次、痕量元素分解效果都有提高,尤其对主量元素分解效果的提高最为明显。测定结果显示,5种元素方法检出限在0.011~42.8μg/g,相对标准偏差(n=9)在2.06%~7.56%,精密度和准确度均满足地质实验室质量管理规范要求,可快速、准确测定地球化学样品中的多元素。展开更多
基金This work was supported by the Knowledge Innovation Program from the Cold and Add Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences （CACX2003102）the Chinese Academy of Sciences （KZCX 1 - 10-03-01）the National Natural Science Foundation of China （40401012）.
文摘Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance of water supply and demand in the region was established, and the security of water resource was assessed, from which the results that the effects of unified management of water resources in the Heihe River basin between Gansu Province and Inner Mongolia on regional hydrology are significant with a decrease in water supply diverted from Heihe River and an increase in groundwater extracted. In addition, it was found that the groundwater level has been steadily decreasing due to over pumping and decrease in recharges. In present year （2003）, the volume of potential groundwater in the irrigation districts is far small because of the groundwater overdraft; even in the particular regions, there is no availability of groundwater resources for use. By 2003, water supply is not sufficient to meet the water demand in the different irrigation districts, the sustainable development and utilization of water resources are not secured, and the water supply crisis occurs in Pingchuan irrigation district. Achieving water security for the sustainable development of society, agriculture, economy, industry, and livelihoods while maintaining or improving the abilities of the management and planning of water resources, determining of the reasonable percentage between water supply and groundwater utilization and water saving in agricultural irrigation are taken into account. If this does not occur, it is feared that the present performance of water development and planning may further aggravate the problem of scarcities of water resources and further damage the fragile ecological system.
基金Project supported by the National Natural Science Foundation of China (No. 40571026).
文摘This study addresses the adaptation of Nitraria sphaerocarpa to blown sand at the edge of a desert oasis with regard to the aspects of soil seed banks, seedlings, and population. Horizontally, the total number of seeds per unit area decreased from the shrub canopy center to intershrub areas, and most seeds were found under shrub canopies. Vertically, the highest proportion of seeds was found at depths of 5-10 cm. The emergence percentage, seedling mass, and seedling height, which were significantly affected by both burial depth and seed size, were highest at the optimal burial depth of 2 cm, and decreased with increasing burial depth in each seed size-class. Although seedling mass was usually greatest for large seeds and least for small seeds at each burial depth, little difference was observed in seedling height at shallow burial depths of 0-3 cm. The population shows a patchy and discontinuous distribution pattern. Population height increases with increasing sand depth. Also the density increases with increasing depth of sand in the desert; however, there is a steady decrease when the depth of sand is more than 100 cm. This result indicates that the depth of sand that is most suitable for the growth of Nitraria sphaerocarpa is 100 cm. The size of the population is significantly correlated with the sand depth, which increases with increasing depth in the desert.
文摘通过改变混合酸(盐酸-硝酸-氢氟酸-高氯酸)中高氯酸的比例,采用石墨管加热消解和电热板加热消解2种方式,残渣用逆王水提取,3%稀硝酸定容测定,建立了一种理想的酸分解方法用于电感耦合等离子体质谱/发射光谱法(ICP-MS/OES)测定地球化学样品主、次、痕量元素。结果表明,当使用10 mL逆王水、5 m L氢氟酸、石墨管加热消解(加入2~3 mL高氯酸),或电热板加热消解(加入3~4 mL高氯酸分解试样),使用10 mL 50%逆王水提取,对主、次、痕量元素分解效果都有提高,尤其对主量元素分解效果的提高最为明显。测定结果显示,5种元素方法检出限在0.011~42.8μg/g,相对标准偏差(n=9)在2.06%~7.56%,精密度和准确度均满足地质实验室质量管理规范要求,可快速、准确测定地球化学样品中的多元素。
