检索结果-南通市图书馆

Migration and accumulation of heavy metals in disturbed landscapes in developing ore deposits, East Kazakhstan

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2013年第2期5卷 180-187页

作者： Gulzhan BEISEYEVA Jilili ABUDUWALI Kazakh Research institute of Soil Science and agrichemistry named for U.U.Uspanov State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences

This paper studied the contents of heavy metals and their accumulation in the disturbed landscapes in ore deposits of East Kazakhstan. A total of 14 sites were examined in Zyrynovsky and Tishinsk deposits and Ridder town, and 50 soil samples were taken. Results indicated that the contents of heavy metals in the soil reached the maximum permissible concentration. Emissions of the zinc plant negatively affected the soil of nearby territories. In the remediated areas, a high concentration of heavy metals was observed at a depth where the bulk soil borders the rock. Accumulation of heavy metals on the surface of the remediated areas occurred due to biological accumulation in the plant. Plants transmitted heavy elements through the root system to the upper vegetative organs, making them accumulate in the upper layers of the soil. The heavy metals migrated and accumulated from the lower layers to the surface layers of the soil. The absence of soil meso-fauna resulted in the contamination of soil by heavy metals. The analysis of water samples, taken from the waste storages and the waste waters with heavy metals in the Zyryanovsk deposit and Ridder town, revealed severe water contamination.

关键词： disturbed lands dumps waste storage heavy metals accumulation migration East Kazakhstan

Fractionation of Rare Earth Elements in Plants Ⅰ. Fractionation Patterns and Their Forming Mechanisms in Different Organs of Triticum Aestivum

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2005年第2期23卷 224-229页

作者：梁涛丁士明张朝生张自立阎军才李海涛 institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Department of Geography and Environmental Change institute National University of Ireland Galway Ireland Department of Soil and agrichemistry Anhui Agricultural University Hefei 230036China

Fractionations of rare earth elements (REEs) and the forming mechanisms in plants were studied using Triticum aestivum as plant material with application of exogenous REEs and hydroponic culture. REEs were significantly fractionated in different parts of Triticum aestivum. M-type tetrad effect could be observed in both root and shoot of Triticum aestivum, which might result from the different abilities of REEs to form phosphate precipitation. Middle REEs (MREEs), light REEs (LREEs) and heavy REEs (HREEs) were enriched in root, stem and leaf of Triticum aestivum, respectively. REE speciation calculations using VMINTEQ program show REEs in simulated xylem solution mainly exist as REE-EDTA^(- )and RE^(3+), but only HREEs are enriched in REE-EDTA^(-), while LREEs are enriched in the other REE species. It is suggested that the fractionation between LREEs and HREEs might be caused by the uptake of REE-EDTA^(-) in Triticum aestivum leaves, but might result from the uptake of the other REE species in their stems.

关键词： fractionation lanthanides tetrad effect Triticum aestivum rare earths

Effect of Rare Earths on Fractionation and Transformation of Soil Available Nitrogen

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2003年第5期21卷 582-586页

作者：丁士明梁涛张自立孙琴张朝生 institute of Geographic Sciences and Natural Resources Research Chinese Academy of Science Department of Soil & agrichemistry Anhui Agricultural University State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Department of Geography and Environmental Change institute National University of Ireland

The effect of rare earths (RE) on fractionation and transformation of available nitrogen in a yellow cinnamon soil was studied with soil cultivation. The results show that under the dry condition, when the extraneous RE are added to the soil, both concentrations of soil ammonium N and hydrolysable N increase, and the concentrations of soil nitric N decrease. The concentrations of soil available N increase with the increase of RE concentrations in soils when the RE concentrations are low, but it decreases with the increase of high RE concentrations in soils. The NOEC (no observed effect concentration) of the extraneous RE to available N in the soils is 443.8 mg·kg -1 . Under the inundated condition, low RE concentrations in soil has no significant effect on soil ammonium N and hydrolysable N. However, when the soil RE concentrations are high, both of them decrease with the increase of RE concentrations. The NOEC of the extraneous RE to soil ammonium N and hydrolysable N are 171.2 and 256.9 mg·kg -1 , respectively.

关键词： pedology nitrogen transformation yellow cinnamon soil rare earths

氮素形态对玉米根尖质外体铁组成影响的短期效应

在线全文

学校读者我要写书评

暂无评论

科学通报 2001年第24期46卷 2058-2062页

作者：邹春琴张福锁 H.E.Goldbach 中国农业大学植物营养系北京100094 institute of agrichemistry

探讨了在模拟铁缺乏条件下（高HCO3-）,分别短期供应铵态氮（NH4+-N）和硝态氮（NO3--N）对玉米（Zea mays L cv Lenz）根尖（0～3cm）质外体铁的组成和FeCN（ferricyanide）还原酶活性的影响.结果表明,玉米根尖质外体Fe（Ⅱ）的绝对浓... 详细信息

探讨了在模拟铁缺乏条件下（高HCO3-）,分别短期供应铵态氮（NH4+-N）和硝态氮（NO3--N）对玉米（Zea mays L cv Lenz）根尖（0～3cm）质外体铁的组成和FeCN（ferricyanide）还原酶活性的影响.结果表明,玉米根尖质外体Fe（Ⅱ）的绝对浓度和相对比例均较低,分别只有20～40nmol/L和7％～13％,绝大部分是以Fe（Ⅲ）形式存在,增加NH4+-N和NO3--N的处理时间有利于提高Fe（Ⅱ）的浓度.与NO3--N相比,NH4+-N提高了玉米根尖质外体Fe（Ⅱ）和交换性铁的浓度和比例,而NO3--N使FeCN还原酶活性增加.此外,还对质外体pH的变化与铁组分和FeCN还原酶活性的关系进行了讨论.

关键词：质外体铁组成氮素形态玉米铵态氮硝态氮短期效应 FeCN还原酶

Spatio-temporal pattern and changes of evapotranspiration in arid Central Asia and Xinjiang of China

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2012年第1期4卷 105-112页

作者： Xi CHEN BaiLian LI Qin LI JunLi LI Saparnov ABDULLA State Key Laboratory of Desert and Oasis Ecology Sino-US International Center of Ecology in Arid Land Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China Ecological Complexity and Modeling Laboratory Department of Botany and Plant Sciences University of California Riverside CA 92521-0124 USA University of Jinan Jinan 250022 China U.U.Uspanov Kazakh Research institute of Soil Science and agrichemistry Ministry of Agriculture of Kazakhstan Almaty 050060. Kazakhstan

Accurate inversion of land surface evapotranspiration （ET） in arid areas is of great significance for understanding global eco-hydrological process and exploring the spatio-temporal variation and ecological response of water resources. It is also important in the functional evaluation of regional water cycle and water balance, as well as the rational allocation and management of water resources. This study, based on model validation analysis at varied scales in fiwe Central Asian countries and China＇s Xinjiang, developed an appropriate approach for ET inversion in arid lands. The actual ET during growing seasons of the study area was defined, and the changes in water participating in evaporation in regional water cycle were then educed. The results show the simulation error of SEBS （Surface Energy Balance System） model under cloud amount consideration was 1.34% at 30-m spatial scale, 2.75% at 1-km spatial scale and 6,37% at 4-kin spatial scale. ET inversion for 1980-2007 applying SEBS model in the study area indicates：（1） the evaporation depth （May-September） by land types descends in the order of waters （660.24 ram）〉 cultivated land （464.66 mm）〉 woodland （388.44 mm）〉 urbanized land （168.16 mm）〉 grassland （160.48 mm）〉 unused land （83.08 mm）; and （2） ET during the 2005 growing season in Xinjiang and Central Asia was 2,168.68x108 m3 （with an evaporation/precipitation ratio of 1.05） and 9,741.03x108 m3 （with an evaporation/precipitation ratio of 1.4）, respectively. The results unveiled the spatio-temporal variation rules of ET process in arid areas, providing a reference for further research on the water cycle and water balance in similar arid regions.

关键词： Evapotranspiration (ET) arid areas SEBS model remote sensing Central Asia Xinjiang of China