Table of Content

15 November 2013, Volume 30 Issue 6 Previous Issue    Next Issue

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Regional Difference of Lakes in the Arid Regions in Central Asia LI Jun-Li, BAO An-Ming, HU Ru-Ji, WANG Ya-Jun 2013, 30 (6):  941-950.  Abstract ( 1537 )   PDF (3840KB) ( 1293 )   Lake is a kind of sensitive indicator of climate and environmental changes. Mapping of the area and monitoring of the change of lakes in arid regions are essential to estimate the effects of climate change and human activities on water resources. In this paper, the change of area of the lakes in Central Asia was mapped with the Landsat images in 2010, and the spatial distribution of number and area of the lakes was also discussed. The results were as follows: (1) There were 30 952 lakes larger than 0.01 km2 in Central Asia in 2010, and their total area was 496 674.35 km2; (2) There was a power exponential relationship between number and area of the lakes. If the lake size was increased from one logarithmic size class to the next bigger one, the lake number was statistically increased by 4-6 times, and total area of the lakes was enlarged by 1-2 times. Compared with the lakes in other regions in the world, the density of lakes in Central Asia was relatively low; (3) The latitudinal spatial distribution of the lakes was relatively uniform, and the large lakes were mainly distributed in the latitudinal zones of 41°-44°N, 46°N and 48°-50°N. The lakes in the lowaltitude regions were more, and their areas were large. However, the lakes in the highaltitude regions were also more, but their areas were small. The lakes in the mountainous regions, valley wetlands and steppes in north Kazakhstan were more than those in deserts; (4) In recent 20 years, the alpine lakes were stable or in an expansion trend, but areas of the lakes in plains were sharply reduced. References | Related Articles | Metrics

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Spatiotemporal Variation of Water Vapor in Upper Troposphere over Central Asia Based on AIRS Satellite Retrieval ZHANG Xue-Qin, LI Min-Jiao, SUN Tong 2013, 30 (6):  951-957.  Abstract ( 1921 )   PDF (2722KB) ( 1102 )   Water resources dispute has become as one of the highlight factors that threaten the national security in Central Asia. As an important component of global water cycle, the distribution and variation of water vapor in upper tropospheric is significative for water resources allocation in Central Asia. This paper discusses the spatiotemporal variation and anomaly of water vapor in upper troposphere over Central Asia during the period of 2003-2011 based on water vapor mass mixing ratio data from the Atmospheric Infrared Sounder (AIRS) satellite instrument, and the obvious differences between Central Asia and the Asian monsoon region (such as the Qinghai-Tibetan Plateau) and tropical monsoon area were revealed. The results revealed that water vapor in upper troposphere over the lowand midlatitude regions in Central Asia maintained a low value, and the monthly variation was relatively stable. Compared with the high water vapor concentration over the south Qinghai-Tibetan Plateau and the northern tropical monsoon area, the Central Asia from the Black Sea-Caspian Sea to west Xinjiang was detected as an area with low water vapor concentration. Water vapor in upper troposphere over Central Asia was slightly increased with a remarkable fluctuation in recent 9 years. The minimum and maximum values of water vapor occurred in 2009 and 2010 respectively, and this significant fluctuation between these two years affected significantly the linear trend of water vapor during the period of 2003-2011. Seasonally, the water vapor concentration was in a slight decrease trend in spring, a slight increase trend in summer, a significant increase trend in autumn, and there was a significant 2-3year fluctuation in winter. References | Related Articles | Metrics

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Variation of Runoff Volume in the Dagu River Basin in the Jiaodong Peninsula JIANG De-Juan, WANG Xiao-Li 2013, 30 (6):  965-972.  Abstract ( 1674 )   PDF (3733KB) ( 922 )   The Dagu River is the largest river in the Jiaodong Peninsula, and it is called as the mother river of Qingdao City. Runoff volume of the river has been sharply reduced since recent decades, and the dryingup of the river course has occurred frequently, which have seriously threatened the economic development and ecosystems. In this paper, the variation of annual and seasonal runoff volumes and the affecting factors were analyzed based on the data of monthly runoff volumes at 3 hydrological stations of Nancun, Chanzhi Reservoir and Yinfu Reservoir as well as the annual precipitation and air temperature data observed by Qingdao Meteorological Station during the period of 1964-2008. The results showed that the annual runoff volume of the river was in a slight reduction in recent 45 years, but its decadal difference was remarkable, especially since the 1980s. The annual runoff volume at Nancun Hydrological Station became zero for many years. There was a sharp change of annual runoff volumes at the 3 hydrological stations in the early1960s, and also a 4year fluctuation quasiperiodicity of annual runoff volume at Yinfu Reservoir Hydrological Station. Seasonally, 89.8% annual runoff volume at Nancun Hydrological Station occurred in flood season. Moreover, the runoff volume at Nancun Hydrological Station was in a notable reduction in flood season and other months except in August and September, its change was not obvious in nonflood season, but the runoff volume was 0 in most years from the 1980s. Seasonal difference of runoff volume between the hydrological stations of Chanzhi Reservoir and Yinfu Reservoir was low compared with that at Nancun Hydrological Station. Compared with the annual runoff volume during the period of 1964-1980, the percentages of reduced annual runoff depth by precipitation reduction and by human activities during the period of 1981-2008 were 52.38% and 47.62% respectively, which revealed that the runoff variation was strongly affected by these two factors. Furthermore, under the background of global climate change, human activities exacerbated the reduction of runoff volume and resulted in the Dagu River to be as a seasonal river. References | Related Articles | Metrics

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Exploitation and Utilization Potentials of Water Resources in Arid Oasis City—A Case Study in Urumqi TANG Hong, XIA Fu-Qiang, YANG De-Gang 2013, 30 (6):  973-980.  Abstract ( 1726 )   PDF (2573KB) ( 827 )   Shortage of water resources has seriously hampered the healthy development of oasis city. Based on the situation of exploitation and utilization of water resources in Urumqi during the period of 1995-2010, in this paper a comprehensive appraisal model was developed for assessing the exploitation and utilization potential of water resources. The results were as follows: (1) Surface water was the main water resources in Urumqi, where the annual volume of water resources was 11.20×108 m3, and the water resources volume per capita was much lower than that in whole Xinjiang. The exploitation and utilization ratio of water resources in Urumqi was rapidly increased, and even the water consumption was higher than the inflow volume; (2) Total water consumption was increased in a fluctuation way, and it was 10.89×108 m3 in 2010. Water consumption was dominated by agricultural production, but the proportion of water consumption for farming was decreased in recent years, and the industrial and domestic water consumption was gradually increased; (3) The background conditions of water resources in Urumqi were significantly deteriorated, but the utilization efficiency and management capability were rapidly improved. Holistically, the exploitation and utilization potential of water resources in Urumqi was gradually decreased in a fluctuation way due to the rapid population growth and economic development as well as the pollution of water resources. References | Related Articles | Metrics

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A Flood in the Ertix River Basin in Xinjiang NU 尔Lan-·Ha-Zai-Zi, MA Ha-Ti-·Mu-La-Ti-Bie-Ke, MA Ha-Sa-Ti-·Ha-Zi-Ha-Li 2013, 30 (6):  981-985.  Abstract ( 1777 )   PDF (1623KB) ( 987 )   A sudden snowmeltrainfall mixed flood with high flood peak and big volume occurred in all the distributaries of the Ertix River Basin on June 1, 2005. In which the flood occurred in the Kuyertes River, a headstream of the Ertix River, was the maximum recorded since recent 50 years, and the 2nd and 3rd maximum floods in the records occurred in the Burqin River and Haba River separately. The flood resulted in a huge economic loss in the local area. In this paper, the causes, process and characteristics of the flood were analyzed based on the observed data of flood, rainfall, temperature and atmospheric circulation pattern. The results were as followings: (1) Previous temperature and largescale precipitation played an important role in the formation process of the snowmeltprecipitation mixed flood in the Ertix River Basin; (2) Temperature change, 0 ℃layer height and precipitation were necessary for accurately predicting flood trend. The 4th basinwide flood recorded since recent more than 50 years occurred under global warming and the obvious increase of snowfall in the Altay region in winter, and the possibility of occurring disastrous flood would be increased; (3) Duration of snowmeltrainfall mixed flood is long, the flood peak is high, and the sandcarrying capability of such flood is strong, so these problems should be paid great attention to in designing the projects of urban flood prevention and control and water storage; (4) Construction of prewarning system of flood prevention and control should be enhanced, especially along the mountainous rivers if there are large cities or important projects downstream so as to decrease the losses caused by disastrous flood. References | Related Articles | Metrics

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Change of Soil Moisture Content under Different Plant Species in Mining and Non-mining Areas in Northwest Shanxi Province WANG Shang-Yi, NIU Jun-Jie, ZHU Wei-Xin, ZHANG Xiu-Wei 2013, 30 (6):  986-991.  Abstract ( 2029 )   PDF (1897KB) ( 989 )   Northwest Shanxi Province is an important part of the Loess Plateau and the farmingpasturing ecotone. On the one hand, it is difficult to guarantee the massive water consumption for mining development due to the serious shortage of water resources, and on the other hand, the aquifers have been seriously damaged and polluted by underground mining, so there is a sharp contradiction between shortage of water resources and massive water consumption. The change of soil moisture content in soil layer of 0-600 cm under 3 different plant species in mining and nonmining areas in northwest Shanxi Province was researched so as to ascertain the depth of soil desiccation, difference of soil moisture content under different plant species and the effect of mining on soil moisture content. The results revealed that the soil moisture content under the 3 plant species in mining and nonmining areas was in an order of Caragana korshinskii > Populus simonii > Hippophae rhamnoides, the depth of soil desiccation was in an order of P. simonii > H. rhamnoides > C. korshinskii, and the average soil moisture content was in an order of mining area < non-mining area. There was a significant positive correlation between soil moisture content and sampling sites and soil depth(P<0.01), but a significant negative one between soil moisture content and plant species (P<0.01). References | Related Articles | Metrics

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Relationship between Particulate Nutrient Content and Nutrient Content in Bulk Soil during Reversal of Desertification CHEN Xiao-Hong, DUAN Zheng-Hu, LUO Tian-Feng, TAN Ming-Liang 2013, 30 (6):  992-997.  Abstract ( 1246 )   PDF (1432KB) ( 937 )   Based on field investigation and laboratory analysis, the values of particulate soil nutrient content and nutrient content in bulk soil were examined using the method of timespace mutual substitution. The statistic analytical methods were used to analyze the relationship between the particulate soil nutrient content and nutrient content in bulk soil during the reversal of desertification in the multipleyear enclosed area to facilitate vegetation regeneration in Yanchi County, Ningxia Hui Autonomous Region. The results showed that, with the reduction of desertification degree, there was a gradual increase trend of the contents of SOC, N, P and K in each particle fraction and of SOC, N, P and K in bulk soil. Correlation analysis revealed that there was a significant positive correlation between the particulate soil nutrient contents in all the particle fractions and the soil nutrient contents in bulk soil. The enrichment of SOC, N, P and K contents in topsoil was a result jointly affected by both the fixation and storage of nutrients in bulk soil and the integration of nutrients in soil with different grains sizes during the reversal of desertification. Path analysis showed that the effects and importance of nutrients in soil with different grains sizes to nutrients in bulk soil were different, and the effects of unprotected particulate nutrients in very fine sand and moderatecoarse sand to nutrients in bulk soil was significant. References | Related Articles | Metrics

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Relationship between Osmotic Potential and Total Salt Content in Saline or Alkaline Soil in Xinjiang CHEN Chun-Xiu, TIAN Chang-Yan 2013, 30 (6):  998-1003.  Abstract ( 1852 )   PDF (1787KB) ( 1596 )   The relationship between osmotic potential and total soil salt content was used to indirectly describe soil salinization degree. Soil osmotic potential measured by extraction was closely related to the soilwater ratio. Therefore, it is very important for setting up the conversion relationships between osmotic potentials in 1∶1 and 1∶5 soilwater extracts. Four hundred and fifty saline or alkaline soil samples with different types and textures were collected in whole Xinjiang, and their osmotic potential (Ψs), total soil salt content ([WTBX]St[WTBZ]), pH value, and main cation and anion concentrations in 1∶1 and 1∶5 soilwater extracts were determined. The results showed that osmotic potential in 1∶1 soilwater extract was significantly associated with that in 1∶5 one, and the conversion relationship could be expressed by equation Ψs1∶1= 4.32Ψs1∶5+0.007 (R2=0.97,P<0.000 1). The relationship between osmotic potential and total soil salt content (St) could be expressed by equation Ψs1∶1=67.26-19.67ln(St1∶1+30.46) (R2=0.96, P]<0.000 1)  in 1∶1 soilwater extract and by equation Ψs 1∶5=232.59-39.82ln(St1∶5+343.68) (R 2=0.90, P<0.000 1) in 1∶5 soilwater extract respectively. For improving saline or alkaline soil and growing halophytes, these equations can be used to quantitatively assess the degree of soil salinization in Xinjiang, and the study results can provide a scientific basis for further researching saline soil or alkaline soil in Xinjiang References | Related Articles | Metrics

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Characteristics of Rare Earth Elements in Loess Profiles in the Ili Basin, Xinjiang GUO Li-Cheng, CHEN Xiu-Ling, SONG You-Gui, JIA Li-Min 2013, 30 (6):  1004-1012.  Abstract ( 1957 )   PDF (1903KB) ( 991 )   Studies on the relations between the Asian aridification and the climate fluctuation in the northern hemisphere and the reconstruction of palaeoenvironment in arid region in north China have attracted extensive global attention in recent years, and more effective means are needed to be applied to reveal the specific mechanisms of them. As we all known, rare earth elements (REE) with similar chemical properties and little changes during weathering transportation and diagenesis are widely used as the trace elements in studying the provenances of various sediments. REE characteristics are closely related to environmental change, so that REE can record the environment evolution in detail. Consequently, REE are widely used as the important indicators in studying paleoclimate. However, few studies on the characteristics and environmental significance of REE in loess in northwest inland area of China were carried out. The characteristics of rare earth elements in loess profiles in the Ili Basin and those in typical loess areas since the Epipleistocene were analyzed and compared. The results revealed that the average content of REE in loess profiles in the Ili Basin was similar to that in the typical loess profiles, and the REE distribution was in an inclined “Lshaped” pattern. The main fractional characteristics were similar and characterized by LREEenrichment and HREEdepletion, the distribution curves were negative oblique lines, and Eu performed a negative anomaly, but the anomaly of Ce was not obvious. Therefore, these loess profiles had the common characteristics, and loess was possibly originated from same sources. However, there were a few differences of the characteristics of REE in the loess profiles in different areas since the Epipleistocene, which was related to the existence of proximal sources of loess profiles in the Ili Basin, different sedimentation environment, and instability of upper air circulation. References | Related Articles | Metrics

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Variation of Soil Nutrient Content and pH Value under Picea crassifolia Forest in the Pailugou Drainage Basin in the Qilian Mountains LIU Xian-De, ZHAO Wei-Jun, ZHANG Xue-Long, JING Wen-Mao, FAN Li-Mei 2013, 30 (6):  1013-1020.  Abstract ( 3445 )   PDF (1601KB) ( 845 )   Forest graybrown soil is distributed in an area where Picea crassifolia grows in the midmountain zone of northern slope of the Qilian Mountains. In this study, P. crassifolia forests at altitudes of 2 900-3 000 m. in the Pailugou Drainage Basin in the Qilian Mountains were selected as the research objects, and 3 sample plots were designed every 100 m altitude gradient. Soil nutrient content and pH value under P. crassifolia forest at different altitudes and different soil depths were measured, and their relationship were researcehd. The results were as follows: (1) In the altitude gradient, the average contents of organic matter, total nitrogen and total phosphorus in soil layer of 0-40 cm at high altitude were higher than those at low altitude, and the difference was significant （P<0.05）. However, the contents of soil total potassium and available potassium at high altitude was lower than those at low altitude, and the difference was also significant（P<0.05）. There was no obvious change of available phosphorus content with the increase of altitude, and the difference was not significant （P＞0.05）.  Soil pH value was decreased with the increase of altitude, and the difference was not significant neither （P＞0.05）.  (2) In different soil depths, the average contents of organic matter, total nitrogen, total phosphorus, available phosphorus and available potassium in soil layer of 0-10 cm were higher than those in soil layers of 10-20 cm and 20-40 cm, and those in soil layer of 0-10 cm were significantly higher than those in soil layer of 20-40 cm （P<0.05）.  Soil pH value and total potassium content were increased with the increase of soil depth, the pH value difference between soil layers of 0-10 cm and 20-40 cm was significant （P<0.05）,but the difference of total potassium content among different soil layers was not significant （P＞0.05）.  (3) The correlation analysis of different soil nutrients and pH value revealed that the soil pH value and soil organic matter content were the dominant factors affecting nutrient supply of P. crassifolia  community in cycles of carbon, nitrogen, phosphorus and potassium. References | Related Articles | Metrics

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Response of Hydraulic Structure Parameters and Growth of Pinus sylvestris var. mongolica Seedling to Simulated Precipitation Gradient SONG Li-Ning, ZHU Jiao-Jun, KANG Hong-Zhang 2013, 30 (6):  1021-1027.  Abstract ( 1537 )   PDF (1485KB) ( 947 )   Water plays a key role in affecting the survival and growth of Pinus sylvestris var. mongolica  (MP) on sandy 1and. In order to understand the response of MP seedlings to water stress, in this study the responses of hydraulic structure and growth parameters of 2yearold MP seedlings to the stimulated precipitation gradients at three levels (105% mean annual precipitation: 500 mm, without drought stress, P1; 74% mean annual precipitation: 350 mm, moderate drought stress, P2; and 42% mean annual precipitation, 200 mm, drought stress, P3) were investigated. The results showed that the water saturated deficit of the seedlings was not changed with the decrease of precipitation, tissue density of the seedlings was significantly increased under P2, and the coefficient of water loss of seedlings was significantly decreased under P3. These revealed that the droughtresistance and waterholding capability of the seedlings were increased with the increase of drought stress. Height and base diameter increment of MP plants and biomass accumulation of organs were restricted by drought stress. The root weight ratio and rootshoot ratio were significantly increased under P2, which revealed that the biomass allocation pattern was altered under P2, and the waterholding capability of the seedlings were promoted. Compared with the situation under P2, the biomass allocation of the seedlings was not changed under P3. In conclusion, the hydraulic structure and biomass allocation of MP seedlings could be changed under P2, but only the hydraulic structure could be changed under P3, which was disadvantageous for the survival of MP seedlings in arid environment. References | Related Articles | Metrics

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Structure and Species Diversity of Meadow Community along the Shaliu River in the Qinghai Lake Basin LI Cheng-Xiu, LI Xiao-Yan, YANG Tai-Bao, LI Yue-Tan- 2013, 30 (6):  1028-1035.  Abstract ( 1691 )   PDF (2186KB) ( 719 )   The Qinghai Lake is located in the northeastern part of the Qinghai-Xizang Plateau. It is the largest inland saline lake in China and an important international wetland. It is also of great importance for protecting ecology in the northeast Qinghai-Xizang Plateau. The steppe in the Qinghai Lake Basin is an important component of terrestrial ecosystems and plays a significant role in biodiversity and ecosystem functions. The vegetation and its distribution in this region is affected by the existence of Qinghai Lake and complicated landscape features. The vegetation was degenerated during the past decades due to climate change, overgrazing and human activities, and the richness of plant species in the area was low. The study on the structure of plant communities in Qinghai Lake Basin can provide a scientific basis for researching the degeneration of riparian vegetation. This research would provide a valuable reference for protecting the biodiversity of the steppe and maintaining the grazing ecosystem functions in the headwaters of the three rivers. Therefore, some field samples were surveyed around the Shaliu River in the Qinghai Lake Basin. Plant communities, aboveground biomass productivity and species diversity in the different locations of the Shaliu River Basin were analyzed, and the factors related to the plant communities were lucubrated. Thirteen experimental locations were selected with altitude ranging from 3 200 m to 3 500 m. The research results were as follows: (1) There were 52 plant species in 39 genera and 13 families in the study area. The species richness, aboveground biomass and average vegetation coverage were significantly different from the different sample plots. The average vegetation coverage was 70%, and the average aboveground biomass was 131 g•m-2. The similarity of species was studied by using Cooccurrence Jaccard Index（CJ）.The result revealed that the value of CJ was decreased with the increase of distance between two profiles. The spatial variability is mainly affected by the local environment conditions; (2) The ShannonWiener index, species richness, species evenness index and aboveground biomass were increased at first and then decreased slight with increasing the distance of sample plots away from the lake, but the average vegetation coverage was increased at first, and then unchanged. Soil moisture content, soil salt content, altitude, [WTBX]etc[WTBZ]. may be the main factors resulted in the difference of spatial distribution of plant communities; (3) There was an inconspicuous linear correlation among the ShannonWiener index, species richness and aboveground biomass. References | Related Articles | Metrics

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Dynamic Change of Vegetation Coverage in Water wind Erosion Ecotone in the Loess Plateau SUN Yan-Ping, ZHANG Xiao-Ping, LIU Jian-Xiang, XU Jin-Peng, CHEN Wen-Kai 2013, 30 (6):  1036-1043.  Abstract ( 1347 )   PDF (2346KB) ( 859 )   NDVI (normalized difference vegetation index) of GIMMS (global inventory modeling and mapping studies) was taken as the data source and the dimidiate pixel model was used to extract the data of vegetation coverage with different grades in waterwind erosion ecotone in the Loess Plateau in periods of 1982-1989, 1990-1999 and 2000-2006. The transition matrix model was used to quantitatively analyze the change of vegetation coverage in the study area. The result showed that the vegetation coverage in the study area was holistically in an increase trend, and it was temporally increased at first and then decreased. Viewing from the spatial distribution, it was found that the proportion of moderatelow vegetation coverage was the highest, then that of low and moderate vegetation coverage, and that of high vegetation coverage was the lowest. In general, the development of vegetation coverage in the study area was virtuous from the period Ⅰ (1982-1989) to the period Ⅲ (2000-2006), and the environment was holistically improved except in some few regions. Analysis revealed that the center of low vegetation coverage was shifted southwestward, and that of moderatehigh and high vegetation coverage was shifted eastward, which indicated that the vegetation in Ningxia and central Gansu in southwest region of the study area was degenerated due to the decrease of precipitation and the impact of urbanization in recent 25 years. However, the ecological construction including the conversion of cropland to forest and grassland has brought good ecological benefits in Wuqi, Zhidan, Ansai, Yan[JP8]’a[JP]n and Dongsheng in Mu Us Sandy Land in the eastern part of the study area Related Articles | Metrics

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Poisonous Plants in Natural Grasslands in Urumqi County and Their Control Measures A De-Li-·Mai-Di, LIU Yan-Yan, GU Li-Nu-尔, KONG Xiao-Xin, NA Bi-Wu-La 2013, 30 (6):  1044-1048.  Abstract ( 1488 )   PDF (752KB) ( 950 )   Dry climate, overgrazing, damaged by rats and invasion of poisonous grass species are the main causes resulting in a degeneration of grasslands, and poisonous grasses have already resulted in a direct menace to all kinds of grasslands. In order to provide a rational scientific base, the distribution of poisonous grass species in natural grasslands in Urumqi County was studied. According to the identification of plant specimens, there were 46 main poisonous grass species in 29 genera and 17 families in the county, and their proportion was 5% of the total. The distribution area of poisonous plant species was 3.27×104 hm2, and it occupied 9.83% of the total grassland area. The main poisonous grass species included Achnatherum inebrians, Peganum harmala, Anabasis aphylla, Stipa capillata, Sophora alopecuroides, Thermopsis lanceolata and Pedicularis oederi. These poisonous plants were perennial herbs, their reproductive capacity was very strong, their growth was rapid, and these poisonous plants were high and competed sunshine, soil moisture and fertilizer with forages, such as Festuca ovina and Agropyron cristatum, which results in a death of fine forages in large area. Control of the growth of poisonous plants was studied, and some measures were put forward for controlling the poisonous plants. Based on the carrying capacity of the natural grasslands, the theoretical grazing intensity was determined so as to provide the advantageous conditions for regenerating fine forages by reducing the number of livestock, implementing a rotational grazing system, and controlling the growth of poisonous plants. Related Articles | Metrics

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Effects of Microhabitat on the Growth of Quercus wutaishanica Seedlings ZHENG Wei-Na- , WANG Xiao-An, GUO Hua, WANG Dan, LIU Peng- , LIU Shi-Li 2013, 30 (6):  1049-1055.  Abstract ( 1218 )   PDF (826KB) ( 940 )   In this paper, Quercus wutaishanica seedlings were selected as the research object to elucidate the effect of microhabitat on the growth of the seedlings. In the Q. wutaishanica forest in Malan forest zone on the Mt. Ziwuling, the growth parameters of 1-3-year-old Q. wutaishanica seedlings and the microhabitat variables were studied by using the typical line transect method and laboratory test. The results showed that the height, stem base diameter, bud number of seedlings of 3-year-old seedlings were significantly different from those of 1-year-old and 2-year-old seedlings. Along with the increase of seedling age, the seedling growth rate reduced gradually, and the microhabitat variables and the growth parameters of seedlings were in an increase trend, which revealed that there was a time lag in the effects of microhabitat on the growth of seedlings. Litters are one of the important factors of restricting seedling growth, a suitable shade of tree layer is an optimal environment for the growth of 1-year-old and 2-year-old seedlings, and the optimal environment for the growth of 3-year-old seedlings is gap. Therefore, gap is necessary for the ecesis of Q. wutaishanica. Related Articles | Metrics

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Change of Landscape Pattern along the Jiuquan-Jiayuguan Section of National Highway 312 XIE Yu-Chu, GONG Jie, QIAN Da-Wen, SUN Peng 2013, 30 (6):  1056-1063.  Abstract ( 2369 )   PDF (3278KB) ( 768 )   As a special land use in landscape, road plays a “corridorbarrier” role and affects surrounding landscapes. The research on road landscape ecology is of an important significance in arid area where the ecology is fragile. Based on the results interpreted from the Landsat TM/ETM+ images of Jiuquan and Jiayuguan cities in 1986, 1996, 2006 and 2010, the land use change and landscape change along the Jiuquan-Jiayuguan section of National Highway 312 (G312) and its ecological effects in different road buffers including 1 000, 2 000 and 3 000 m in width were analyzed using the means of GIS and landscape ecology. The results were as follows: (1) Landscape pattern was significantly changed during the period from 1986 to 2010. The area of construction land was rapidly enlarged, that of unused land was reduced, unused land was promptly converted to construction land, and the dominance of unused land was weakened. The aggregation and radiation effects of the G312 were quite difference from different road buffers; (2) Change of the corridor structure of the Jiuquan-Jiayuguan section of the G312 was significant, and the connectivity and channel function of the Jiuquan-Jiayuguan section of the G312 were increased; (3) Because of the infrastructural construction of G312 and its neighboring highway G30, the patch density and heterogeneity of landscapes along these highways were increased. A certain aggregation of some patches in different buffers was brought about, and the fragmentation, diversification and homogenization of landscapes along the G312 occurred; (4) Effects of the G312 on landscape pattern were the most significant within a buffer width zone of 2 000 m but over 3 000 m in central Jiuquan and Jiayuguan cities. Urban expansion, economic development and landscape pattern change were the important factors affecting the ecology along the G312. Related Articles | Metrics

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Gradient Change of Landscape Pattern in the Mainstream Area of the Tarim River BAI Yuan, XU Hai-Liang, LIU Xin-Hua, LING Hong-Bo, FU Jin-Yi 2013, 30 (6):  1064-1072.  Abstract ( 1228 )   PDF (2382KB) ( 954 )   In this paper, the holistic landscape pattern and its spatial difference in the mainstream area of the Tarim River in Xinjiang were analyzed based on GIS and quantitative analysis. According to the physical geographical features in the drainage basin, 35 buffer zones were delimited along the transversal gradient of 5 river sections, Fragstats was used to select the landscape indexes at both landscape level and landscape type level, and the landscape pattern gradients were analyzed and compared. The results were as follows: (1) The area of natural vegetation occupied 35.1% of the total landscape area, and that of other land use types occupied 54.88%, so the latter was the background of landscapes in the drainage basin. The area of lowcoverage grassland in a continuous distribution trend was the largest, that of highcoverage grassland was spatially distributed in an aggregated way, the patches of forestland were small and were separated by other landscapes, the patch number of farmland was the most, and the landscape diversity and landscape heterogeneity were decreased from the upper reaches to the lower reaches of the Tarim River; (2) Heterogeneity of the spatial pattern of land use was significantly high, showing a gradient pattern with geographical gradient and buffer zone, the river corridor change was the driving power resulting in the variation of landscape patterns, the corridor widths of the Tarim River was 8.6-10 km, 6.6-8.1 km, 4.8-4.9 km and 1.4-5 km along the river section 1, 2, 3 and 4 respectively. The change trend of the indexes with the change of buffer zone width could be used to reflect the intensity of potamic effect; (3) At the landscape type level, the landscape indices reflected the sensitivity degree of different landscape types to the potamic effect, the forestland was mainly distributed in a corridor width of 1-5 km, the sparse forestland in 1-10 km, the highcoverage grassland in 1-9 km, and the lowcoverage grassland in 1-12 km. An analysis method of landscape pattern in buffer zone was developed, and it was used to reveal the dynamic trend of landscape gradient and the extent of ecological benefits in the river corridoroasisdesert ecotone so as to formulate more effective development policy and provide a reliable basis for regenerating the degenerated ecology. Related Articles | Metrics

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Sustainable Development in Northern Slope of the Tianshan Mountains Based on Improved Model of Carrying Capacity Related to Resources WANG Fei, YANG De-Gang, WANG Chang-Jian, ZHANG Yu-Fang, TANG Hong, YIN Jing-Jing 2013, 30 (6):  1073-1080.  Abstract ( 1031 )   PDF (2250KB) ( 718 )   Endowment of natural and economic resources is not only an important guarantee of regional population growth, but also the basis of sustainable development. Based on the improved model of carrying capacity related to resources, in this study the values of population carrying capacity and economic carrying capacity related to resources in northern slope of the Tianshan Mountains during the period from 2000 to 2010 were calculated. The spatiotemporal evolution and difference of these two carrying capacities in 14 counties and cities were investigated. The results were as follows: ① Compared with the situation in whole Xinjiang, the population growth was high and there was an overload or serious overload of economy related to resources in northern slope of the Tianshan Mountains in recent decade; ② Compared with the situation in whole Xinjiang, water resources were advantageous to sustainable development in northern slope of the Tianshan Mountains, but land resources were disadvantageous to restrict population growth and economic development; ③Compared with the situation in northern slope of the Tianshan Mountains, the surplus degree of population carrying capacity related to resources was the highest in Karamay City, and the overload was the most serious in Bole City; the overload of economic carrying capacity related to resources was the most serious in Karamay City, and the surplus degree was the highest in Qitai County; ④ According to the overload status or surplus degree of population carrying capacity and economic carrying capacity related to resources in the 14 counties and cities, the northern slope of the Tianshan Mountains was classified into four matching modes. Related Articles | Metrics

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Dynamic Evolution of Landscape Pattern around the Historical and Cultural Resources in the Turpan Region MENG You, ZHANG Ying 2013, 30 (6):  1081-1086.  Abstract ( 2779 )   PDF (1156KB) ( 824 )   The Turpan region in Xinjiang is rich in historical and cultural resources. In this study, the change of landscapes around the historical and cultural resources in the Turpan region was analyzed by applying the means of remote sensing (RS), geographic information system (GIS) and statistics based on the RS images in 1990, 1999 and 2010. The main results were as follows: (1) The approaches of natural science and the technology of space information can be used to improve the quantitative studies on some social subjects in protecting the historical and cultural resources; (2) From the view of time, the change of total number of patches of the historical and cultural resources during the period of 1990-2010 was not significant, the Shannon diversity index was decreased from 0.965 2 to 0.837 6, Shannon evenness index was increased from 0.436 8 to 0.521 7, and the landscape dominance index was decreased to some extent; (3) From the view of different landscapes, the historical and cultural resources affected slightly by human activities were the marine cemetery, Asa Xeher ancient city ruins and Kotantur ancient city ruins; those affected strongly by human activities were the Gaochang ancient city ruins, Jiaohe ancient city ruins and Sugong Tower. According to the study results, some suggestions were put forward for protecting and managing the historical and cultural resources in the Turpan region. Related Articles | Metrics

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Research Progresses of Ecological Effects of Farmland Drainage System Evolution in Arid Area FENG Yi-Xing, LUO Ge-Ping, XU Wen-Qiang, HAN Qi-Fei, WANG Yuan-Gang- 2013, 30 (6):  1087-1093.  Abstract ( 1183 )   PDF (933KB) ( 1069 )   Soil salinization and its continual improvement during the formation and development of oasis drought about the farmland drainage system landscape in downstream of oasis and area nearby desert. However, the ecological benefits of farmland drainage system evolution were unclear, which limited the comprehensive understanding about the ecological processes of artificial oasis ecosystem. In this paper, the formation, evolution, process and development pattern of farmland drainage system in recent 50 years were analyzed using the aerial photos, Landsat MSS, TM/ETM and SPOT image data in the downstream of oasis based on the graph theory, network analysis and model for landscape connectivity. Effects of the evolution of farmland drainage system on the ecological corridor, soil properties, land use change and species diversity were studied based on the buffer analysis, spatial geostatistic model, GIS correlation analysis and community diversity measurement. Furthermore, the improved biogeochemical model was used to explore the effects of farmland drainage system evolution on the regional carbon cycle and water cycle as well as the interactional mechanism between the farmland drainage systems evolution and the terrestrial ecosystem. It is of an important scientific significance for achieving the oasis agricultural sustainable development to deeply understand the effects of human activities on ecological environment in arid area and enrich the content of oasis ecology research. Related Articles | Metrics

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Spatiotemporal Distribution and Formation Causes of Precipitation in the East of Northwest China during the Period of 1961-2009 ZHU Xiao-Wei, YANG Jian-Ling, CUI Yang, TAN Zhi-Qiang 2013, 30 (6):  1094-1099.  Abstract ( 1245 )   PDF (3695KB) ( 1053 )   The spatiotemporal distribution of precipitation was researched based on the monthly precipitation data form 99 meteorological stations in the east of northwest China. The results revealed that the precipitation in the study area was slightly decreased, especially in autumn, and there was no significant sharp change of annual precipitation. Precipitation in autumn was in an increase trend in recent decade. Precipitation in the east of northwest China occurred mainly in the southof Ningxia and the east of Qinghai. There were the 4, 8 and 12year periodicities of precipitation. EOF was used to analyze the annual precipitation, the first mode was identical in all the regions, the second one was different between the north and the south, and the third one was different between the west and the east. Based on the ground conditions, it was found that the landforms, especially the plateaus, Liupanshan Mountain, deserts and Gobi deserts (including the Badain Juran Desert, Tengger Desert and Mu Us Sand Land), were the important factors affecting precipitation in the east of northwest China. Related Articles | Metrics

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Near-surface Horizontal Aeolian Sand-dust Flux over an Oasis-desert Ecotone in Qira County, Xinjiang YANG Xing-Hua, HE Qing, CHENG Yu-Jing, FAN Xin-Ming 2013, 30 (6):  1100-1105.  Abstract ( 1223 )   PDF (1220KB) ( 826 )   Aeolian sanddust transport is a serious problem in many arid regions in the world, and it is considered to be as a significant part of global biogeochemical cycle. Deserts are the main sources of nearsurface aeolian sanddust transport, and aeolian sanddust transport process is closely related to the variation of nearsurface horizontal aeolian sanddust flux with height. In this paper, the variation of horizontal aeolian sanddust flux within height 2 m above the ground surface was discussed based on the oneyear observation on a level sand land in the south Taklimakan Desert by BSNE samplers. It was revealed that the horizontal aeolian sanddust flux was decreased with the increase of height, which could be described with the distribution of power function and exponential function. A 55%-58% amount of horizontal aeolian sanddust was transported within an air layer 0.5 m above the ground surface, a 73%-75% amount of that was transported within an air layer 1 m above the ground surface, and a 87%-89% amount of that was transported within 1.5 m above the ground surface. In the study area, the amount of horizontal aeolian sanddust load in a height range from 0 to 2 m was 1 846.7 kg•m-1, in which the amounts of PM80 and PM50 were 1 192.0 kg•m-1 and 387.9 kg•m-1 respectively. Related Articles | Metrics

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Precipitation in the Weihe River Basin in Recent 60 Years LAI Wen-Li, SONG Jin-Xi, ZHANG Jie, REN Chao-Liang, DU Jia 2013, 30 (6):  1106-1112.  Abstract ( 1928 )   PDF (3337KB) ( 1195 )   Based on the daily, monthly and annual precipitation data from the meteorological stations of Tianshui, Baoji, Wugong and Xi‘an during the period of 1951-2011, the change trend of precipitation was analyzed using the linear regression, MannKendall test and fiveyear moving average method. It could be concluded that the seasonal distribution of precipitation was quite different in the Wei River Basin, precipitation occurred mainly in summer and autumn, it was in an obvious decrease trend in spring and autumn, and its variation trend was not obvious in summer and winter. However, the seasonal distribution of precipitation was quite different from different years. There was a sharp change of seasonal precipitation except in summer, and also of annual precipitation. There was a 28-32year fluctuation period of precipitation. The precipitation days in the drainage basin were in a reduction trend, but the intensity of light rain was in an increase trend. During the period of 1976-1990, the rainstorm days were the most at the meteorological stations of Tianshui, Baoji and Wugong except at Xi[JP8]’a[JP]n Meteorological Station, and they were quite different from different years Related Articles | Metrics

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Assimilated Test of Humidity Field in Single Occultation Event MA Yu-Fen, LI Man, SHI Lian-Mei 2013, 30 (6):  1113-1121.  Abstract ( 1134 )   PDF (3687KB) ( 1253 )   A selected Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation (RO) event point was assimilated into the Advanced Weather Research and Forecast Model (WRF) Data Assimilation (DA) system. Analyses with and without single Wet Profile COSMIC occultation event were compared with each other. Zonal mean temperature, humidity and surface pressure differences between the GPS analyses and NOGPS analyses were examined. Particular case of occultation event wetPrf_C003.2009.145.00.32.G07_0001.0002_nc at 47.648°N and 73.830°E occurred at 00:32 o’clock, May 25th, 2009, used in this study, contained 400 pieces of records, in which 7 pieces were uncompleted, 85 pieces failed to pass the quality control procedure, and 307 were assimilated to the initial field. The wellobserved 393 pieces of records were distributed in the altitude range from 0.7 km to 31.4 km, latitude range from 47.399 34°N to 48.179 68°N, and longitude range from 73.669 02°E to 74.264 92°E. The typical duration of an occultation event was 3 minutes. Although only 307 pieces out of 400 items of the single point were ingested and water vapor was not directly related to wind, the assimilation did lead to an improvement of wind and temperature as well as the pressure analysis through internal model dynamic adjustment. Temperature was increased near the occultation event on the northwest side at 850 hPa and 500 hPa and on the southeast side at 200 hPa, but the temperature was decreased on the southeast side at 850 hPa and 500 hPa and on the northwest side at 200 hPa. The positive increment of water vapor mixing ratio occurred on the northwest side at all the levels, and the negative one on the southeast side. Both the positive and negative increments of temperature and water vapor mixing ratio were distributed around the occultation point in a quasisymmetry way. The increase and decrease of temperature occurred on both sides of 300 hPa level, but basically around the occultation point, and the increase and decrease of the water vapor mixing ratio occurred mainly at an altitude below 30 km. The maximum value (2.2×10-3 kg•kg-1) occurred near ground (47.5°N, 72.5°E). The DA of the single wet profile of GPS occultation point did contribute not only the improvement of prediction level of rainfall along the Tianshan Mountains, but also the reduction of false precipitation in the north piedmont of the Qinghai-Tibetan Plateau. Related Articles | Metrics

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Spatiotemporal Change of the Oasis in Gaotai County in Recent 50 Years TIAN Wen-Ting, JIE Yao-Wen, CHEN Yun-Hai 2013, 30 (6):  1122-1128.  Abstract ( 1152 )   PDF (4110KB) ( 982 )   Distribution of the oasis in Gaotai County, Gansu Province was extracted by taking the 13 images in recent 50 years as the data sources, including LandsatMSS/TM, KeyHole and KATE-200. The single dynamic degree and bidirectional dynamic degree of the oasis were calculated, the relative change rates of the oasis in all the townships and towns in Gaotai County were estomated, and an overlay analysis on the vector data about distribution of the oasis in 13 periods were carried out to get the area and spatial change of the oasis in time sequence. The results showed that the oasis in Gaotai County was in expansion in recent 50 years, especially during the period from 1990 to 1993. The analyzed results of bidirectional dynamic degree revealed that the conversion between oasis and nonoasis was violent. The stable parts of the oasis were mainly distributed along the Heihe River and around the residential areas, the changeable parts of the oasis were distributed surrounding the oasis. The urban and rural areas of Luotuo Town and Nanhua Town were the main areas where the oasis was in expansion, and the frequent expansion and shrinkage of the oasis occurred mainly in Luocheng, Xinba, Heiquan townships. Related Articles | Metrics

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Identification and Screening of Salt Tolerance of Main Cotton Varieties in Xinjiang YANG Shu-Ping, WEI Chang-Zhou, LIANG Yong-Chao 2013, 30 (6):  1129-1135.  Abstract ( 1383 )   PDF (1440KB) ( 921 )   Germination experiments and hydroponic experiments were carried out to identify the salt tolerance of 30 cotton varieties planted in Xinjiang. The results revealed that, in the 30 cotton varieties, proportion of the cotton varieties with high salt tolerance (at level Ⅰ) at their bud stage was 16.67% only, that with certain salt tolerance (at level Ⅱ) was 43.30%, and that sensitive to salt and with moderate salt tolerance was 40.00%. At seedling stage, there was no any cotton variety with high salt resistance, there were 8 cotton varieties with salt tolerance at level Ⅱ, and the proportion of cotton varieties with salt tolerance at level Ⅲ was 63.30%. At bud stage, there was an extremely significant positive correlation between the relative bud length and the relative root length, but a significant negative correlation between the relative bud length and the saltharmful index. At seedling stage, there was a significant positive correlation between the rootshoot ratio and the saltharmful index, and the salt tolerance at bud stage could be used to indirectly reflect the salt tolerance at cotton seedling stage. Related Articles | Metrics

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Value of Water and Soil Conservation in Land Ecosystem in the Guanzhong-Tianshui Economic Zone ZHANG Wei, LI Jing 2013, 30 (6):  1136-1143.  Abstract ( 1040 )   PDF (1715KB) ( 1011 )   Calculation of the value of water and soil conservation is of an important significance for sustainable land use and coordinate ecological and environment development. A case study of calculating the value of water and soil conservation in the Guanzhong-Tianshui economic zone in 1980, 2000, 2005 and 2010 was carried out based on the remote sensing data, DEM data and statistical data using the geographic information system and remote sensing means. The calculated results showed that the value of water and soil conservation in the Guanzhong-Tianshui economic zone was increased year by year, its increase trend became more significant, and it was increased by 2.54×1010 yuan during the period from 1980 to 2000, by 1.56×1010 yuan during the period from 2000 to 2005, and by 3.59×1010 yuan during the period from 2005 to 2010. In which the value of water and soil conservation was high in cultivated land, woodland and meadow, but low in waters, urban and rural construction land and unused land. In addition, there was a positive correlation between the distribution of value of water and soil conservation and vegetation coverage. In order to improve the value of water and soil conservation in the study area, it is suggested to strengthen the protection of basic farmland and woodland and grassland construction, and improve the coverage of woodland and meadow. Related Articles | Metrics

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Driving Forces and Dynamic Prediction of Cultivated Land Area Change in Xi’an YI Lang, REN Zhi-Yuan, LIU Yan-Xu 2013, 30 (6):  1144-1149.  Abstract ( 1336 )   PDF (1076KB) ( 951 )   The principal component analysis was used to extract the features of indicator factors, the grey prediction method was applied to construct the prediction indexes, and the MATLAB software and BP neural network were used to predict the change of area of cultivated land in Xi[JP8]’a[JP]n. The results showed that the BP neural network was characterized by the simple structure, fast convergence and high precision after analyzed with the principal component analysis. The accuracy of predicted annual reduction of area of cultivated land with the BP neural network was high, and the BP neural network was reliable and feasible. The predicted results showed that the area of cultivated land in Xi[JP8]’a[JP]n in 2013 was 248 826.67 hm2.The reduction of area of cultivated land in Xi[JP8]’a[JP]n was mainly caused by the rapid economic development and the increase of urbanization level. It was suggested to pay great attention to the planning and protection of cultivated land resources in Xi[’an in the urban development. Related Articles | Metrics