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Nuclear Science and Techniques 2015年第4期26卷 46-50页

作者： Bouzid Nedjimi Brahim Beladel laboratory of exploration and valuation of the steppe ecosystem Faculty of Science of Nature and Life University of Djelfa University of Djelfa

Instrumental neutron activation analysis(INAA)has been used to determine some chemical element contents(K,Ca,Na,Fe,Zn,Co,Eu,Sb,and Sc)in Traganum nudatum Del(Chenopodiaceae family)consumed in North African rangelands by sheep *** were collected from the area of Djelfa in an arid steppe of *** show that pasture halophyte had sufficient levels of K,Ca,Zn,and Co to meet the requirements of ***,it seems that this halophyte shrub had substantial amounts of Na,higher than the critical level established by the National Research Council(NRC).Eu,Sb,and Sc were within the safety baseline of all the assayed elements recommended by the *** high Na content(～10 g/kg)in this halophytic species requires elevated intake of water by livestock.

关键词：仪器中子活化分析化学元素含量灌木评价盐生植物阿尔及利亚钙水平 INAA

Seasonal variation of selected trace elements in rare endemic species Thuriferous Juniper growing in the Aurès Mountains of Algeria

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Journal of Forestry Research 2017年第2期28卷 249-254页

作者： M.E.Bacha B.Nedjimi A.Ararem B.Beladel laboratory of exploration and Valorization of steppe ecosystem Faculty of Science of Nature and LifeUniversity of DjelfaCite Ain ChihP.O.Box 3117Djelfa 17000Algeria Neutron Activation Analysis Department Nuclear Research Center of BirineP.O.Box 180Ain Oussera 17200Algeria

We used energy dispersive X-ray fluorescence（EDXRF） to determine the seasonal variation of selected trace elements（Cr, Mn, Zn, Cu, Se and Fe） and some potential toxic elements（Cd, Pb and Br） in Juniperus thurifera subsp. africana Maire（Cupressaceae） a rare medicinal tree, growing indigenously in Aures Mountains of Algeria. The precision of the results was assessed by analyzing the certified reference material IPE44（WEPAL）grass leaves. Results showed J. thurifera was characterized by high Cr and Mn contents. During autumn and winter mineral concentrations were higher in general. The levels of Cr, Se and Mn were higher during autumn and winter than during spring and summer. Zn contents were higher during summer than in other seasons. Cu content did not vary by season. The potential toxic elements in J. thurifera（Pb [ Cd [ Br） were below the permissible limits recommended by the Joint WHO/FAO guidelines except for Pb in autumn and winter.

关键词： autumn winter seasonal certified EDXRF endemic subsp dispersive assessed medicinal

Effects of sand-fixing and windbreak forests on wind flow:a synthesis of results from field experiments and numerical simulations

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Journal of Arid Land 2017年第1期9卷 1-12页

作者： ZHAN Kejie LIU Shizeng YANG Zihui FANG Etian ZHOU Lanping HUANG Ning Key laboratory of Mechanics on Western Disaster and Environment in China(Ministry of Education) Department of MechanicsLanzhou UniversityLanzhou 730000China Minqin National Station for Desert steppe ecosystem Studies Minqin 733000China

Sand-fixing and windbreak forests are widely used to protect or/and improve the ecological environments in arid and semi-arid regions. A full understanding of wind flow characteristics is essential to arranging the patterns of these protective forests for enhancing the effectiveness. In this study, the wind velocity over the underlying surface with sand-fixing forests and windbreak forests at the heights of 1–49 m was monitored from two 50-m high observation towers in an oasis of Minqin, Gansu Province of China. The wind velocities were simulated at different locations over these protective forests between those two towers by a two-dimensional Computational Fluid Dynamics（CFD） model. The results showed that at the heights of 1–49 m, the wind velocity profiles followed a classical logarithm law at the edge of the oasis and a multilayer structure inside the oasis. With increasing number of sand-fixing forest and windbreak forest arrays, the wind velocity at the heights of 1–49 m generally decreased along the downstream direction of the prevailing wind. Specifically, below the height of windbreak forests, the wind velocity decelerates as the airflow approaches to the windbreak forests and then accelerates as the airflow passes over the windbreak forests. In contrast, above the height of windbreak forests, the wind velocity accelerates as the airflow approaches to the windbreak forests and then generally decelerates as the airflow passes over the windbreak forests. Both the array number and array spacing of sand-fixing and windbreak forests could influence the wind velocity. The wind protection effects of sand-fixing forests were closely related to the array spacing of windbreak forests and increased with the addition of sand-fixing forests when the array of the forests was adequately spaced. However, if the array spacing of windbreak forests was smaller than seven times of the heights of windbreak forests, the effects were reduced or completely masked by the effects of

关键词： wind velocity sand-fixing forest windbreak forest computational simulation Minqin

Differences in response of desert plants of different ecotypes to climate warming:a case study in Minqin, Northwest China

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Journal of Arid Land 2012年第2期4卷 140-150页

作者： ZhaoFeng CHANG ShuJuan ZHU FuGui HAN ShengNian ZHONG Minqin National Station for Desert steppe ecosystem Studies Minqin 733300 China Gansu Key laboratory of Desertification Combating Lanzhou 730070 China Gansu Desert Control Research Institute Lanzhou 730070 China

Globally climates are warming. How do desert plants of different ecotypes respond to the climate change？ This paper studied the differing responses to climate warming shown by desert plants of different ecotypes through analyzing the phenology and meteorological data of 22 desert plant species growing in Minqin Desert Bo- tanical Garden in Northwest China during the period 1974-2009. The results indicate：（1） The temperature in the study area has risen quickly since 1974, and plants＇ growing periods became longer. The spring phenology of mesophytes advanced, and the autumn phenology of xerophytes was delayed; （2） The starting dates of spring phenophase of mesophytes and xerophytes differed significantly and both showed an advancing trend; （3） The spring phenology of mesophytes advanced by more days than that of xerophytes, whereas the autumn phenology of mesophytes was delayed by less days than that of the xerophytes; and （4） Mesophytes are more sensitive than xerophytes to rising temperature in spring and falling temperature in autumn. These findings are of value in plant management and regional introduction of different species.

关键词： desert plants plant phenology phenophases ecotypes climate warming Minqin

Spatial heterogeneity of soil water content in the reversion process of desertification in arid areas

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Journal of Arid Land 2011年第4期3卷 268-277页

作者： QuanLin MA Fang CHENG YouJun LIU FangLin Wang DeKuai ZHANG HuJia JIN Gansu Key laboratory of Desertification Combating ＆ Minqin National Studies Station for Desert steppe ecosystem Gansu Desert Control Research Institute Lanzhou 730070 China Institute of Desertification Studies Chinese Academy of Forestry Beijing 100091 China

Sandy soils in arid,rain-fed environments have low and limited water content,which is a principal factor limiting vegetation development,and a key constraint controlling the structure and functions of the ecological systems in arid *** spatial heterogeneity of soil water content is a major soil property,and a focus of soil science and *** the southern edge of the Tengger Desert,sample plots were selected from mobile sand dunes in desertified lands that had been enclosed for 5,15 and 25 years,*** study explored the dynamic and spatial heterogeneity of soil water content in these different layers of soil that were also in the reversion process of *** results showed that the soil water content of the mobile sand dunes was highest when in the initial stages of the reversion process of desertification,while the soil water content in the 0-20 cm,20-40 cm and 40-60 cm layers of soil was 1.769%,3.011%,and 2.967% respectively,presenting a restoring tendency after 25 years of *** were significant differences,as a whole,in the soil water content among different restoration stages and different soil layers,*** in soil water content,in different soil layers,at different restoration stages,exhibited exponential or spherical *** spatial distribution of soil water content exhibited a mosaic patch pattern with obvious spatial *** ratio of the heterogeneity of spatial autocorrelation to gross spatial heterogeneity was greater than 50%.The gross spatial heterogeneity of the 0-20 cm layer of soil improved gradually,while those of the 20-40 cm and 40-60 cm layers improved initially,then weakened in the reversion process of *** study revealed that restoration with sand-binding vegetation reduced soil water content,and increased its spatial heterogeneity in arid ***,after 25 years of vegetation-soil system restoration,the soil water content started to increase and it

关键词： Tengger Desert reversion process of desertification soil water content sand-binding vegetation geostatistical analysis

Dynamics of Above-and Below-ground Biomass and C,N,P Accumulation in the Alpine steppe of Northern Tibet

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Journal of Mountain Science 2011年第6期8卷 838-844页

作者： LU Xuyang YAN Yan FAN Jihui CAO Yingzi WANG Xiaodan Key laboratory of Mountain Environment Evolvement and Regulation Institute of Mountain Hazards and Environment CAS Chengdu 610o41 China Shenzha Alpine steppe and Wetland ecosystem Observation and Experiment Station Institute of Mountain Hazards and Environment CAS Shenzha 85310o China

The temporal dynamics of the biomass, as well as the carbon （C）, nitrogen （N）, phosphorus （P） concentrations and accumulation contents, in above- and below-ground vegetation components were determined in the alpine steppe vegetation of Northern Tibet during the growing season of 2OLO. The highest levels of total biomass （311.68 g m-2）, total C （115.95 g m-2）, total N （2.60 g m-2）, and total P （0.90 g m-2） accumulation contents were obtained in August in 2010. Further, biomass and nutrient stocks in the below-ground components were higher than those of the above-ground components. The dominant species viz., Stipa purpurea and Carex moorcrofli had lower biomass and C, N, P accumulations than the companion species which including Oxytropis. spp., Artemisia capillaris Thunb., Aster tataricus L., and SO on.

关键词： Biomass Nutrient concentration Nutrient accumulation Alpine steppe Northern Tibet

High ecostoichiometric stability and accumulating SiO2 and NO3- as main physiological adaptive mechanisms for reed to adverse environments

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Research in Cold and Arid Regions 2024年第5期16卷 250-258页

作者： JianJun Kang Fan Yang DongMei Zhang LiWen Zhao Key laboratory of Ecological Safety and Sustainable Development in Arid Lands Linze Inland River Basin Research Station Chinese Ecosystem Research NetworkNorthwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Minqin National Studies Station for Desert steppe ecosystem Gansu Desert Control Research Institute

Previous studies have shown that nutrients accumulation played important roles in resisting to stress resistance of *** study examined the ecostoichiometric internal stability （EIS） of nutrients accumulation and,concomitantly identified the main resistant regulating substances and their contributions to stress resistance of reed （Gramineae） in arid desert *** （digging method） and soil samples （quartering method）) obtained from sand dune （SD）,desert steppe （DP）,interdune lowland （IL）,saline meadow （SM） and wetland （W） habitats were brought back to the lab for nutrients *** indicated that soil nutrients differed obviously,while reed maintained relatively stable ratios of SiO2:N,N:K,and P:K when the eco-environments changed in different ***,reed exhibits common adaptive characteristics by mainly accumulating large amounts of SiO2（122.6–174.0 g/kg） and NO3-（166.1–216.6 g/kg）,as well as moderate levels of soluble sugar （SS:24.0–55.0 g/kg）,which are mainly stored in leaves for stress *** contribution of ions to stress resistance was 80.03%–91.15%（with SiO2and NO3-accounting for 54.91%–63.10%）,whereas the contribution of solutes was only 8.85%–19.97%（with SS contributing to 5.14%–10.91%） in different *** findings suggest that maintaining relatively high EIS,while still accumulating SiO2and NO3-as main physiological regulators might be an effective strategy for reed to positively respond to adverse habitats,which provide a strong theoretical basis and technical reference for searching useful methods for restoration and reconstruction of the degraded ecosystems in desert oasis regions.

关键词： Adaptive strategy Desert oasis Gramineae Nutrients Stoichiometric characteristics

Characteristics of the lower layer of sandstorms in the Minqin desert-oasis zone

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Science China Earth Sciences 2011年第5期54卷 703-710页

作者： ZHAO Ming ZHAN KeJie YANG ZiHui FANG ErTian QIU GuoYu WANG QiangQiang ZHANG YinChang GUO ShuJiang LI AiDe ZHANG JingChun Gansu Minqin National Station for Desert steppe ecosystem Studies Wuwei 733000 China Gansu Desert Control Research Institute Wuwei 733000 China Key laboratory for Urban Habitat Environmental Science and Technology School of Environment and Energy Peking University Shenzhen Graduate School Shenzhen 518055 China

By measuring the sand-dust flux,vertical deposition,and the wind velocity throughout 19 sandstorms in the Minqin region,we quantitatively analyzed the horizontal distribution and vertical variation in sandstorm characteristics under different land cover *** effect of different land cover on mitigating sandstorms was also *** results indicated that,in the surface layer ranging from 0-50 m,the intensity of sand-dust horizontal flux and concentration of sand-dust decreased with the increase of the height in the desert and the edge of oasis,whereas the two physical quantities increased slightly with the increase of the height in the *** two physical quantities obey power function well under all three cover ***,in the desert and at the edge of oasis,the sand-dust vertical deposition decreased with the increase of the *** a partial unimodal distribution at the oasis site and the maximum deposition occurred at the height of 9 m,which corresponds to the middle height of farmland protection *** annual flux that passed through a section of 1 m in width and 50 m in height was 9169 kg in the desert,5318 kg at the edge of oasis,and 2345 kg in the *** the annual fluxes at the edge of oasis and in the oasis are 42% and 74% less,respectively,than that in the *** implies that the wind break forest significantly reduced the intensity of sandstorms.

关键词： Minqin the lower layer sand-dust horizontal flux vertical deposition

Stem sap flow of Haloxylon ammodendron at different ages and its response to physical factors in the Minqin oasis-desert transition zone, China

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Journal of Arid Land 2023年第7期15卷 842-857页

作者： QIANG Yuquan ZHANG Jinchun XU Xianying LIU Hujun DUAN Xiaofeng Minqin National Station for Desert steppe ecosystem Studies Minqin 733300China Gansu Desert Control Research Institute Lanzhou 730000China College of Forestry Gansu Agricultural UniversityLanzhou 730000China

Haloxylon ammodendron, with its tolerance of drought, high temperature, and salt alkali conditions, is one of the main sand-fixing plant species in the oasis-desert transition zone in China. This study used the TDP30(where TDP is the thermal dissipation probe) to measure hourly and daily variations in the stem sap flow velocity of H. ammodendron at three age-classes(10, 15, and 20 years old,which were denoted as H10, H15, and H20, respectively) in the Minqin oasis-desert transition zone,China, from May through October 2020. By simultaneously monitoring temperature, relative humidity,photosynthetically active radiation, wind speed, net radiation, rainfall, and soil moisture in this region, we comprehensively investigated the stem sap flow velocity of different-aged H. ammodendron plants(H10,H15, and H20) and revealed its response to physical factors. The results showed that, on sunny days, the hourly variation curves of the stem sap flow velocity of H. ammodendron plants at the three age-classes were mainly unimodal. In addition, the stem sap flow velocity of H. ammodendron plants decreased significantly from September to October, which also delayed its peak time of hourly variation. On rainy days, the stem sap flow velocity of H. ammodendron plants was multimodal and significantly lower than that on sunny *** daily water consumption of H. ammodendron plants at H10, H15, and H20 was 1.98, 2.82, and 1.91kg/d, respectively. Temperature was the key factor affecting the stem sap flow velocity of H. ammodendron at all age-classes. Net radiation was the critical factor influencing the stem sap flow velocity of *** at H10 and H15;however, for that at H20, it was vapor pressure deficit. The stem sap flow velocity of H. ammodendron was highly significantly correlated with soil moisture at the soil depths of 50and 100 cm, and the correlation was strengthened with increasing stand age. Altogether, our results revealed the dynamic changes of the stem sap flow

关键词： Haloxylon ammodendron stem sap flow stand age soil moisture water consumption Minqin oasis-desert transition zone

Canonical Correlation Factors Causing the Formation of Accumulated Sand-belts along the Oasis Fringe in Hexi Corridor

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Animal Husbandry and Feed Science 2014年第5期6卷 279-284页

作者： Chang Zhaofeng Wang Qiangqiang Zhang Jianhui Tang Jinnian Zhu Shujuan Fan Baoli Zhang Dabiao Liu Shizeng Zhang Guozhong Li Aide Minqin National Station for Desert steppe ecosystem Studies Gansu Desert Control Research Institute

Accumulated sand-belts refer to those formed along the oasis fringe,especially at the upwind location,due to the accumulation of sand blocked by farmland windbreak. In the 60 years since the foundation of new China,a lot of trees have been planted for desertification combating in northwest and north China,thus,accumulated sand-belts were formed at the upwind location. The formation and the ecological effects of the accumulated sand-belts along the oasis fringe is a new scientific concern. To study the formation causes of these belts in Hexi corridor,21 samples were selected,and the height / width of the belts,as well as the vegetation,soil,soil moisture and climatic factors were investigated. This paper analyzed the correlation between the height / width of the belts and the vegetation,soil,soil moisture and climatic factors using the methods of variance analysis,correlation analysis and canonical correlation analysis. The results indicate that: the accumulated sand-belts take a trend of being high and wide in the east whereas low and narrow in the west,and most of the parts tend to be stable; the species on the belts are dominated by Tamarix austromongolica,the vegetation cover and the pure vegetation cover of different dominant species on the leeward slope of the accumulated sand-belts vary significantly. The canonical correlation analysis shows that: the height and width of accumulated sand-belt is the interaction of precipitation,distance to the sand source,leeward vegetation cover and annual average wind speed. Moreover,the height of accumulated sand-belts are negatively correlated to the soil moisture at the depth of 30- 50 cm,air humidity and leeward vegetation cover,and the width of the belts is also negatively correlated with the distance to the sand source. The ecological effects of the accumulated sand-belts are both positive( stopping sands from moving into farmland,protective role as an obstacle)and negative( when the belts decay and activate one day,th

关键词： Height of accumulated sand-belt Width of accumulated sand-belt Climatic and environmental factors Canonical correlation factors Ecological effects Hexi of Gansu