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干旱区研究

Table of Content

    15 July 2014, Volume 31 Issue 4 Previous Issue    Next Issue
    Characteristics of Atmospheric Boundary Layer and PM10 Pollution in a Cold Weather Process
    FENG Xin-Yuan, WANG Shi-Gong
    2014, 31 (4):  585-590. 
    Abstract ( 1462 )   PDF (1739KB) ( 1515 )  
    The characteristics of atmospheric boundary layer structure and turbulent flux transport in a cold weather process and their relations with PM10 pollution in Lanzhou on April 19, 2007 were analyzed based on the data of gradient measurements of meteorological tower, turbulent flux measurements and PM10 concentration observed at Semiarid Climate and Environment Observatory of Lanzhou University. The main results revealed that there was a temperature inverse layer before the occurrence of the cold weather process. As the cold front passed by, the temperature inverse layer was broken, and a mixing layer developed quickly. The vertical gradients of air temperature and humidity in the lower boundary layer was sharply decreased, and that of wind speed was significantly increased. The PM10 concentration was increased at first and then decreased. The vertical turbulent transport was very strong when the cold front passed by. The vertical momentum fluxes of meridional and latitudinal velocity were transported downward, and the vertical momentum flux of the meridional velocity was high. The turbulent momentum downward transported, especially the downward momentum flux of meridional velocity, was the main factor which caused the dust blowing and the PM10 pollution at the beginning of the cold weather process.
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    Scattering/absorption Properties of Aerosol and Its Affecting Factors over Urumqi in Spring and Winter
    CHEN Xue-Gang, WEI Jiang, REN Quan, ZHANG Ke-Lei
    2014, 31 (4):  591-595. 
    Abstract ( 1144 )   PDF (905KB) ( 978 )  
    The serious air pollution in Urumqi is caused by the special hill and valley terrains, irrational energy structure and increase of the consumption of heating energy in winter, which intensify the environmental problems. Even in the better environment, people still feel that the city is being shrouded by “black fog”. The present study investigated one of the important factors, [WTBX]i.e.[WTBZ] the impact of atmospheric aerosols on light. Aiming at revealing the different periods of aerosols affecting visible light, the integrating nephelometer was used to observe the scattering and absorption coefficients of aerosols during the period from January to May 2012. The variations of aerosol scattering and absorption coefficients in winter and spring were analyzed based on the meteorological and pollutant concentration data. The results showed that the change trends of scattering and absorption coefficients in winter and spring were similar, and their curves were Wshaped. The maximal values of scattering and absorbing coefficients in winter and spring were 1 210 Mm-1, 244 Mm-1, 95 Mm-1 and 42 Mm-1 respectively. Moreover, the scattering and absorbing coefficients in winter were 10-20 and 5-10 times of that in spring. The results indicated that the extinction of aerosols was mainly depended on scatting. There was a significant correlation between the relative humidity and wind speed and the scattering and absorbing coefficients. The reason was that the increase of air relative humidity helped the aerosol condensation and the increase of aerosol particle size. Wind speed had a positive effect on the scattering and absorption of aerosols, and it also played an important role in concentration reduction and dispersion of pollutants. There was a significant correlation between pollutant concentration and scattering and absorption coefficients, and the effect of PM 10 and NO2 on the scattering coefficient was higher than that of absorbing coefficient. The results indicated that the contribution of PM 10 to the scattering coefficient was higher than that to the absorption coefficient in north China. SO2 and NO2 affected significantly the scattering and absorbing coefficients of aerosols. It could be conclude that the effects of different pollutants on the scattering and absorption coefficients of aerosols were different.
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    Variation of Surface Ozone Concentration and Its  Affecting Factors in Korla City, Xinjiang
    LIU Xin-Chun, ZHONG Yu-Ting, HE Qing, YANG Xing-Hua, HUO Wen, AI Li-?Mai-Mai-Ti-Ming-
    2014, 31 (4):  596-603. 
    Abstract ( 1490 )   PDF (2547KB) ( 856 )  
    High surface ozone concentration causes harm to human health and also affects plant growth. Ozone is a kind of important greenhouse gas and affects global climate change. In this paper, the daily, weekly, monthly and seasonal variations of surface ozone concentration under different weather conditions were analyzed based on the observation data of surface ozone concentration in Korla City, the largest city in south Xinjiang during the period from July 1, 2010 to June 30, 2012 and also the corresponding meteorological data. Moreover, the main factors affecting the variation of ozone concentration were discussed. The results were as follows: ① The daily variation curve of ozone concentration was unimodal, and the nocturnal variation was gentle but the diurnal one was significant; ② The highest value of ozone concentration occurred on Sunday and the lowest one on Wednesday; ③ The highest average monthly concentration was 82.1 μg•m-3 and occurred in June 2011, and the lowest one was 19.2 μg•m-3; ④ Ozone concentration in spring and summer was higher than that in autumn and winter, and the variation trend was similar to that in other coastal and mainland large and mediumsized cities; ⑤ Seasonally, the daily ozone concentration varied the most significantly in summer and spring, then in autumn, and the slightest in winter. Under different weather conditions, the daily ozone concentration varied the most significantly on sunny day, then on dust weather day, and gently on rainy and cloudy days; ⑥ The daily variation of PM10 concentration was contrary to that of ozone concentration, and the latter was significantly earlier than the former; ⑦ The variation of near surface ozone concentration could be affected by some meteorological factors, such as the relative humidity, wind speed, wind direction and sunshine duration, so ozone pollution was jointly affected by many factors.
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    Impact of Climate Change and Human Activities on Vegetation Coverage in the Mongolian Plateau
    ZHOU Xi-Yin, SHI Hua-Ding, WANG Xiu-Ru
    2014, 31 (4):  604-610. 
    Abstract ( 1537 )   PDF (3019KB) ( 1645 )  
    Global climate change and Global Change and Terrestrial Ecosystems (GCTE) are currently the hot and difficult topics in researching global change. Climate change impacts significantly the global ecosystems, and it has become as an important issue to ascertain the interaction between climate change and ecosystems at different scales and reveal the responses of ecosystems to climate change. Based on GIMMS Normalized Difference Vegetation Index (NDVI) data in the Mongolian Plateau during the period from 1981 to 2006, the spatial and temporal variations of vegetation coverage were studied, and the factors affecting the change of vegetation coverage were analyzed from the perspectives of climate change and human activities. Vegetation coverage in the Mongolian Plateau was generally improved in a fluctuation way during the period of 1981-2006, and the improvement included the following phases: ① Relatively stable phase during the period of 1981-1988; ② Persistently increasing phase during the period of 1989-1993; ③ Relatively low phase during the period of 1994-1998; and ④ Persistently increasing phase during the period of 1999-2006. There was an obvious zonal spatial and temporal distribution of annual maximum NDVI in the Mongolian Plateau during the period of 1981-2006, and the NDVI change trend was different from different land use types: The vegetation in forest area with high NDVI value was in degeneration, there was a significant negative correlation between temperature and precipitation, and the area with vegetation regeneration was much smaller than that with vegetation degeneration. The vegetation coverage in farmland with relatively low NDVI value was in a significant increase trend, there was a significant increase trend of both temperature and precipitation, the NDVI value was obviously increased under the dramatic effect of human activities, and the area with vegetation regeneration in farmland and grasslands were much larger than that with vegetation degeneration.
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    Modification of Key Parameters in CoLM
    LIU Yong-Qiang, AI Li-·Mai-Mai-Ti-Ming, HE Qing-
    2014, 31 (4):  611-618. 
    Abstract ( 1453 )   PDF (1298KB) ( 883 )  
    It is one of the challenges in land modeling to modify and validate the land surface models based on the integrated observation in desert. Particularly, the key parameters and parameterization schemes for desert need to be evaluated insitu so as to improve the models. In this paper, the landsurface key parameters and modified parameterization schemes in the common land model (CoLM) were calibrated based on the annual data (from October 1, 2008 to September 30, 2009) observed in the hinterland of the Taklimakan Desert, and some data were ignored and removed due to the instrument malfunction or electronic and physical noise, [WTBX]etc.[WTBZ] First, aerodynamic roughness length was reevaluated based on the data obtained by Eddy Covariance System and MoninObukhov similarity theory; the accuracy of surface emissivity was improved with two different methods, which was calculated by contemporaneous different data; the fixed parameter of surface albedo was revised to parameterization scheme in order to consistent with its annual variation; the scheme of thermal roughness length that performed best was selected to replace the defaulted one; the original values of soil thermal conductivity were equal in 10 layers when the model was run, they were calibrated into different values in different layers. Second, the key parameters and parameterization schemes were revised and simulated in CoLM. The simulated values were compared with the observed ones. Third, the variation of standard deviation between the observation and simulation by revised parameters or parameterization schemes in every month were compared and analyzed.
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    Progress of Indices and Models of Drought Risk Assessment at Global Scale
    YIN Yuan-Yuan, WANG Jing-Ai, HUANG Xiao-Yun, LEI Yong-Deng
    2014, 31 (4):  619-626. 
    Abstract ( 1072 )   PDF (939KB) ( 890 )  
    In the context of climate change, the frequency and impact of drought at global scale is in an increase trend. As a scientific foundation and basis for disaster prevention and relief, the research on drought risk assessment has attracted widespread attention both at home and abroad. Drought risk assessment at national and regional scales started earlier and deeper, yet drought risk assessment at global scale is currently at the beginning stage. In this paper, a systemic review was carried out at the aspects of data sources, basic units, index system, risk assessment models, and case studies of global drought. Our findings indicated that a significant progress of drought risk assessment at national and regional scales has been achieved, which could provide the valuable references for drought risk research at global scale. With the development of quantitative study on drought hazard and socioeconomic vulnerability assessment, drought risk research at global scale is currently in a holistic trend of multiindex integration with an increasing number of quantitative assessment models. The drought assessment indicators tend to be constructed based on a multisource dataset and multifactor integration. It is important to develop more quantitative models for drought risk assessment. It is of great significance to explore and work out a set of vector units. Future drought risk assessment at various spatiotemporal scales should be carried out based on the quantitative construction of vulnerability curves so as to provide more scientific references for drought risk governance all over the world.
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    Climate Suitability Degree and Its Change for Spring Wheat in Dryland  in the Hilly-gully Region of the Loess Plateau —A Case Study in Mazichuan Village, Lijiabao Township, Dingxi City
    LI Yue, NIU Jun-Yi, LI Guang, NIE Zhi-Gang
    2014, 31 (4):  627-635. 
    Abstract ( 1064 )   PDF (2888KB) ( 746 )  
    In this paper, the climate suitability degree at different growth stages of spring wheat was studied so as to reveal the influence of global warming on agricultural production and assess quantitatively the effects of meteorological factors on the growth of spring wheat. The membership model and the climate suitability degree model were used to research the suitability degree of temperature, precipitation and sunshine at different growth stages of spring wheat in dryland during the period of 1970-2010 based on the fuzzy mathematical theory and the moving average simulation. The results showed that the suitability degree of temperature and precipitation at growing stage of spring wheat decreased, but the variation of suitability degree of sunshine was not significant. In growth period of spring wheat, the suitability degree of sunshine was the highest, then that of temperature, and that of precipitation was the lowest, so inadequate precipitation was the main meteorological factor restricting the growth of spring wheat in Gansu Province. The suitability degree of precipitation was the lowest at seedling stage of spring wheat, and then in heading period. The suitability degree of temperature was the lowest at seedling stage, the variation coefficient was the highest, and these revealed that precipitation and temperature were the key factors affecting the growth of spring wheat at seedling stage, and then in heading period. Precipitation was the most significant factor restricting the growth of spring wheat in dryland, and the climate suitability degree was in a decrease trend with climate change, which was negative for the growth of spring wheat. Global climate change has increased the climate risk of wheat production in the hillygully region of the Loess Plateau.
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    Response of Granularity Distribution to Wind Erosion in the Playa of the Ebinur Lake, Xinjiang, Northwest China
    GE Yong-Xiao, JI Li-Li-·A-Bu-Du-Wai-Li, MA Long, ZHANG Deng-Qing
    2014, 31 (4):  636-642. 
    Abstract ( 1257 )   PDF (1969KB) ( 1065 )  
    Wind erosion, especially in arid zone, is one of the basic geomorphologic processes that shapes different landscapes. The playa of the Ebinur Lake suffers from strong wind erosion, which may cause the occurrence of harmful sand (salt) storms. In order to understand the variation of granular distribution in the playa of the Ebinur Lake, the granular distribution parameters were used to characterize the response of granular distribution to wind erosion in the selected three regions in a bare desert including S1, S2 and S3, where [WTBX]Phragmites australis, Haloxylon ammodendron[WTBZ] and [WTBX]Halocnemum strobilaceum[WTBZ] are the dominant species. The results showed that the fraction content at the same soil depth was significantly different from the different sample sites due to the different time of the formation of deposits in different regions. Generally speaking, the study area S1 was mainly consisted of clay, silt and very fine sand, and the silt content was as high as 80.60%. In the study area S2, the sand content was as high as 87.71%, and the average particle size ranged from 2.25Φ to 3.54Φ. However, the study area S3 was consisted of silt, very fine sand, fine sand and midsized sand, and the average particle size varied from 3.38Φ to 5.65Φ. The response of fraction content and granular parameters of sediment from the three typical regions to wind erosion was different. The average particle sizes (0-10 cm) and granular distribution of sediment in the covered area were significantly different from that in the area without cover. Moreover, such difference was reduced with the increase of soil depth.
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    Meteorological and Antifrost Effects in Flower Season of Peach Trees Covered with Black Plastic Film in Early Spring
    XU Yan-Ping, YAO Xiao-Hong, WAN Xin, SHEN Dong-Mei, REN Hua-Rong, YANG Rui, WU Ting-Fang
    2014, 31 (4):  643-648. 
    Abstract ( 1246 )   PDF (679KB) ( 910 )  
    In order to effectively protect peach trees against frost disaster in early spring, the tests of meteorological and antifrost effects were carried out in Qi[JP8]n’[JP]an County, Gansu Province in flower season of peach trees covered with black plastic film in April 2012. The results revealed that black plastic film could be used to effectively increase the temperature and humidity of topsoil, the average temperature and humidity of topsoil (0-40 cm) could be increased by 0.3-0.4 ℃ and 2-6 percentage points, and the average temperature at 50-150 cm peach canopy was increased by 1.3 ℃. Thus, the growth of peach trees could be improved, the antifrost capability of peach trees could be improved, and the temperature of topsoil and peach canopy could be significantly increased, especially at night. The temperatures of peach canopies protected by covering black plastic film and smoking were 4.2 ℃ and 2.1 ℃ respectively during the period of 04:00-07:00 o’[JP]clock on April 13, 2012, and they were 1.2 ℃ and 0.9 ℃ higher than those without protection. Therefore, it was suggested to protect peach trees with black plastic film against frost disaster in early spring.
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    Water Sources of Three Typical Plants in the Beijing Mountain Areas in Rainy Season
    DENG Wen-Ping, YU Xin-Xiao, JIA Guo-Dong, LI Ya-Jun, LIU Yu-Jie
    2014, 31 (4):  649-657. 
    Abstract ( 1393 )   PDF (2248KB) ( 1205 )  
    Water is the most important factor affecting plant growth, primary production and ecosystem stability in rocky mountain areas in north China. In the rocky mountain areas in north China, there are three main plant species including Platycladus orlentalis, Quercus variabilis and Vitex negundo var. heterophylla, and they adapt to the dead soils well in such arid region and play an important role in vegetation regeneration in Beijing mountain areas. In order to understand the water sources of these species after rainfall in rainy season, the direct inference of hydrogen and oxygen isotopes and multisource mass balance assessment were used to estimate the water sources of these plant species based on the characteristics of stable isotopes of rainwater, soil water, groundwater and plant xylem water. The results were as follows: ① After rainfall, Platycladus orlentalis used mainly the upper soil (0-10 cm) water (35.8%) and the deepsoil (deeper than 80 cm) water (55.6%); ② The water sources of Q. variabilis were similar to those of P. orlentalis, the utilization rate of deepsoil water was higher than that of P. orlentalis,but that of uppersoil water was lower. The utilization rates of shallowsoil water and deepsoil water were 17.7% and 77.2% respectively; ③ The water sources of  Q. variabilis were the most complicated, but the proportion of uppersoil (0-10 cm) water was still dominant (46.6%). Our findings revealed that there was a difference of water use modes among plant species, thus the effective utilization of soil water was improved, the interspecific water competition in the semiarid ecosystem was reduced, and these were important for the species selection in ecological regeneration in the rocky mountain areas in north China.
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    Climate Response of Tree Ring Width at Upper Treeline in the Altay Mountains, Xinjiang
    CUI Yu, ZHANG Tong-Wen, YUAN Yu-Jiang, YU Shu-Long, SHANG Hua-Ming, ZHANG Rui-Bo
    2014, 31 (4):  658-664. 
    Abstract ( 1132 )   PDF (2465KB) ( 649 )  
    In this study 246 tree cores were obtained from 109 Larix sibirica trees at four sites (named as AKL, TEA, TZB and BLS) at the upper treeline in the Altay Mountains, northwest China. The correlation coefficients between the treering width chronologies and climate signals revealed that the correlation coefficient between the BLS and TEA chronologies was the highest (R=0.411, P<0.01). The synchronization of the highfrequency domain was higher than that of the lowfrequency domain in the four standardized treering width chronologies. The climate response of the treering width chronologies from the upper treeline in the Altay Mountains revealed that the main factor affecting the growth of tree rings from the AKL chronology in the northwest Altay Mountain was temperature; that in the TEA and TZB chronologies from the central Altay Mountain was precipitation, and then temperature; and that in the BLS chronology from the southeast Altay Mountain was precipitation. From the northwest to the southeast of the Altay Mountains, the effect of temperature on the growth of tree rings at the upper treeline was gradually decreased, but that of precipitation was gradually increased.
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    Status and Quality of Water Sources in the Kalamari  Ungulate Nature Reserve]—A Case Study in the Released Area of Equus przewalskii
    ZHANG Yong-Jun, ZHANG Feng, CAO Qing, HU De-Fu, CHU Hong-Jun
    2014, 31 (4):  665-671. 
    Abstract ( 1285 )   PDF (919KB) ( 1138 )  
    Water and water quality are the important factors for the survival of wild animals in arid area. In this study, three types of water sources, [WTBX]i.e.[WTBZ] the reconstructed water sources (RW), artificial water sources (AW) and natural water sources (NW) in the released area of [WTBX]Equus przewalskii[WTBZ] in the Kalamari Ungulate Nature Reserve, were systemically surveyed, the water samples were collected, and their quality was measured so as to scientifically assess water quality and conserve and manage the local wild animals in the nature reserve. ICP and IC were used to analyze water quality. High concentrations of Na, F- and SO2-4 were found in the local water sources, and their overstandard rates were 60%, 24% and 28% respectively. Na and SO2-4 concentrations in perpetual NWs were higher than their standards. Most ionic concentrations in the temporary NW were lower than those in the perpetual NW, except F- concentration which was 80% higher than the standard and much higher than that of other water sources. Except Mg and Fe, most ionic concentrations in the RW were similar to those in the perpetual NW. Compared with AW, the ionic concentrations in the RW were decreased except F- concentration. Holistically, the ionic concentrations were in an order of AW>NW≈RW. The results revealed that the F- concentration was high in the temporary NW, so it should be paid great attention to removing F- when reconstructing water sources. The volume and quality of RW are improved, and the RW are the most important water sources for wild animals in the nature reserve. So reconstruction of water sources is advantageous for wild animals, and it is suggested to do it from the extensive way to the intensive way so as to reduce the formation of AW.
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    Variation of Extreme Runoff Volume at Debouchure  of the Heihe River Based on GPD Model
    HUO Xue-Li, LIU You-Cun, HAO Yong-Hong, WANG Jie, HAN Tian-Ding, WANG Jian
    2014, 31 (4):  672-681. 
    Abstract ( 1360 )   PDF (1823KB) ( 1071 )  
    In this paper, the Generalized Pareto Distribution (GPD) model was used to predict the extreme values of average monthly runoff volume at debouchure of the Heihe River in different return periods. The return levels of extreme average monthly runoff volume in both flood season and dry season were analyzed based on the average monthly runoff volume data collected at Yingluoxia Hydrological Station from 1944 to 2010. In order to make the use of GPD model to predict the average minimum monthly runoff volume in dry season, the opposite number of the average monthly runoff volume below 20 m3•s-1 was taken to transform the minimum into the maximum. Under both cases, a proper threshold was selected by the mean residual life plot and by observing the change of modified scale parameter and shape parameter against thresholds. The maximum likelihood method was used to estimate the scale parameter and the shape parameter in GPD model. The different return levels of the extreme average monthly runoff volume of the Heihe River were calculated based on the fitted GPD model. The results showed that the average maximum monthly runoff volumes at the 25year, 50year, 100year and 150year return levels were 219.8 m3•s-1, 235.3 m3•s-1, 249.5 m3•s-1 and 257.4 m3•s-1, and the average minimum monthly runoff volumes at corresponding return levels were 9.0 m3•s-1 , 8.8 m3•s-1, 8.6 m3•s-1 and 8.5 m3•s-1, respectively. The results of the average minimum monthly runoff volume in dry season suggested that the cessation probability of the Heihe River was extremely small under current climate change. Moreover, the 95% confidence interval at the 100year return level of the extreme average maximum monthly runoff volume was ［228.3, 303.1］ in flood season, and the estimation of the 100year at return level of the average monthly runoff volume in dry season was very close to the average minimum monthly runoff volume observed by a deviation of 0.08 m3•s-1. The results indicated that the GPD model has a high accuracy in estimating the return levels of extreme values of average monthly runoff volume in the mountain areas of the Heihe River Basin.
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    Snow ice Disaster Indexes and Risk Assessment in the Pastoral Area in North Xinjiang
    WANG Jian-Gang, WANG Sheng-Tao, ZHUANG Xiao-Cui, BA He-Ti-?Si-Ha-Ke
    2014, 31 (4):  682-689. 
    Abstract ( 1034 )   PDF (4047KB) ( 735 )  
    The features and risk of snow ice disasters in north Xinjiang were researched after analyzing the H and L indexes based on the aggregation, weights and animal husbandry disaster losses of the snowice climate events. It was considered that the snowice disasters were chain structured, and the disaster intensity was related to the weights and aggregation degree of snowice climate events. Based on the information diffusion theory, the risk of snow ice disasters was assessed, the snowice disasters in north Xinjiang were holistically distributed in a northwestsoutheast zonal way, and the occurring frequency of snow ice disasters in the west, hilly regions and areas with thick snow cover was higher than that in the east, plains and areas with thin snow cover.
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    Permeability Coefficients of Streambed Sediment Tested with Different Aqueous Solutions
    YANG Xiao-Gang, LUO Lin, SONG Jin-Xi, REN Chao-Liang
    2014, 31 (4):  690-695. 
    Abstract ( 1286 )   PDF (1580KB) ( 1107 )  
    In this study, the effects of physical and chemical reactions of water on streambed permeability were deeply researched. The head down standpipe penetration test was used to test streambed vertical permeability coefficients, conducted at 98 test sites in the Weihe River Basin in Shaanxi Province, and the sediment samples were collected insitu from the test sites, and they were tested with different aqueous solutions in laboratory. The results showed that the streambed vertical permeability coefficients tested with tap water were much higher than those tested with river water or nutrient solution. The streambed vertical permeability coefficient tested with nutrient solution was decreased at first and then increased. The effect of aqueous alkali on streambed vertical permeability coefficient was negative. Moreover, there was an extremely significant negative correlation between streambed vertical permeability coefficient and alkalinity of river water, but an extremely significant positive one with CODMn.
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    Effects of Different Standing Forest Conditions on Runoff Formation  and Sediment Yield in the Central Tianshan Mountains
    WANG Xiao-Kang, ZHANG Yu-Tao, ZHANG Xin-Ping, LI Ji-Mei, LI Xiang
    2014, 31 (4):  696-701. 
    Abstract ( 1028 )   PDF (671KB) ( 749 )  
    In this study, the grey correlation analysis was used to analyze the factors affecting runoff formation and sediment yield in 14 runoff plots with different standing forest conditions in the central Tianshan Mountains.The research results revealed that there were the differences of the factors affecting runoff formation and sediment yield in these plots.The factors affecting sediment yield were in an order of precipitation>standing forest density>canopy live branch height>thickness of litters>canopy density>slope; the factors affecting runoff formation were in an order of precipitation>thickness of litters>canopy density>standing forest density>canopy live branch height>slope.The standing forest conditions affecting runoff formation and sediment yield were as follows: the natural forests were in an order of immature forest 3>nearmature forest>immature forest 4>mature forest>young growth>immature forest 2>immature forest 1; the plantations were in an order of mingled forest>tending forest pervious to light>pruning tending forest>forest without tending; and the shrubberies were in an order of the shrubberies with 0.6 coverage>the shrubberies with 0.8 coverage.
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    Effects of Soil Erosion on Soil Physicochemical Properties and Soil Microorganisms
    HU Chan-Juan, LIU Guo-Hua, GUO Lei, LIU Yu
    2014, 31 (4):  702-708. 
    Abstract ( 1291 )   PDF (3375KB) ( 982 )  
    Soil erosion is a serious problem in the Loess Plateau. It reduces soil productivity, causes irreversible soil and soil nutrient loss. Although many studies about the effects of soil erosion on soil nutrients, sediments and runoff have been done, the quantificational research on the relationship between soil erosion and soil nutrients, especially with soil microorganisms, was limited. In this study, the 137Cs tracer method was used to research the relationship between soil erosion with soil physicochemical properties and soil microorganisms in erosion environment in the hilly area of the Loess Plateau. The experiment was conducted in the Yangjuangou Valley located near Ya[JP8]n’[JP]an City in north Shaanxi Province, China. Four typical hill slopes including F (artificial forest), G (grass), GFG (grass on upper and lower slopes and artificial forest on middle slope) and FGF (artificial forest on upper and lower slopes and grass on middle slope) were chosen. On each of the four slopes, soil sampling sites were distributed on the summit, shoulder, backslope, footslope and toeslope along the hillslopes. Soil samples were collected in August 2007 for analyzing of the concentration of 137Cs which could indicate soil erosion degree, soil physicochemical properties including the soil organic carbon content, total soil nitrogen content, soil bulk density, electrical conductivity, pH value, soil water content and soil microbial properties including soil microbial carbon, soil microbial functional diversity and soil microbial community structure. The results showed that the concentration of 137Cs varied significantly between different slope positions, and the distribution of 137Cs along hillslope was different under four vegetation patterns. There was a significant regression relationship among soil organic carbon content, total soil nitrogen content, soil bulk density, electrical conductivity and 137Cs concentration.Soil organic carbon content, total soil nitrogen content and bulk density were increased with the increase of 137Cs concentration but the decrease of electrical conductivity. There was no significant correlation between the soil water content and pH value and the concentration of 137Cs. There was no direct impact of soil erosion on soil microbial biomass and neither the significant relationship between 137Cs concentration and soil microbial biomass. However, the regression analysis indicated that soil erosion could affect significantly soil microbial diversity and soil microbial community. Soil microbial functional diversity was decreased, and soil bacterial biomass was decreased at first and then increased with the increase of 137Cs concentration. In conclusion, soil erosion could directly impact the distribution of soil nutrients and soil structure on slope.
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    Effects of Vegetation Regeneration on Soil Organic Matter Content and Water Stable Aggregates in the Weibei Dryland
    DONG Li-Li
    2014, 31 (4):  709-714. 
    Abstract ( 1229 )   PDF (1415KB) ( 992 )  
    The formation of soil water stable aggregates and their protective effects on soil organic matter content can be changed by regenerating vegetation. The content of water stable aggregates and soil organic matter under different landuse types in north Liquan County, the Weibei Dryland was analyzed. The results showed that the percentage content of soil water stable aggregates larger than 0.25 mm, mean weight diameter and soil organic matter content were higher in woodland and permanent wasteland than those in farmland, and the fractal dimension of water stable aggregates in farmland was higher than that in woodland and permanent wasteland. Moment method parameter [WTBX](Cs)[WTBZ] was negative in farmland and oneyear waste land but positive in woodland and permanent wasteland. There was a linear positive correlation between soil organic matter content and mean weight diameter of water stable aggregates. Moreover, the organic matter content in soil water stable aggregate with a diameter less than 0.25 mm was the lowest, and it was increased linearly with the increase of diameter of water stable aggregate. Which revealed that the mineralization of soil organic matter within soil water stable aggregate was reduced, and soil organic matter provided a good material base for the formation of larger soil aggregate. Soil organic matter content and water stable aggregates can be improved by regenerating vegetation in the Weibei Dryland.
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    Enzyme Activities and Physicochemical Properties of Soils in the Ebinur Lake Nature Reserve in Xinjiang, China
    RAN Qi-Yang, 吕Guang-Hui , WEI Xue-Feng, LIU Dong, CUI Nan-
    2014, 31 (4):  715-722. 
    Abstract ( 1092 )   PDF (1355KB) ( 889 )  
    In this paper, the influence intensity of soil physicochemical properties on soil enzyme activities was studied with the methods of correlation analysis and path analysis based on analyzing 4 soil enzymatic activities including catalase, urease, invertase and alkaline phosphatase and 7 soil physicochemical properties including soil moisture content, total salt content, pH value, organic matter content, total N content, available phosphorus content, and available nitrogen content of different soils in a typical desert ecosystem in the Ebinur Lake Nature Reserve. The results showed that soil enzyme activities and physicochemical properties were obviously different from the five soil types. Specifically, the soil enzyme activities and physicochemical properties of chernozem soil were better than those of other soils. Path analysis revealed that soil organic matter content was the leading factor affecting soil enzyme activity; available phosphorus content was the main factor affecting soil catalase activity and had the maximum path coefficient and determinative coefficient; soil total nitrogen content was the decision factor of urease activity and had the highest direct path coefficient; available nitrogen content had the intensive effects on invertase and phosphatase activities; soil total salt content was the main factor of restricting soil invertase. Compared with correlation analysis and stepwise regression analysis, path analysis could be used to objectively and comprehensively assess the influences of soil physicochemical properties on soil enzyme activity.
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    Soil Conditions and Vegetation Regeneration in Zhangye City
    WANG Qiang, JIANG Zhi-Rong, ZHANG Yun-Liang
    2014, 31 (4):  723-727. 
    Abstract ( 1079 )   PDF (675KB) ( 910 )  
    AHP and Euclidean distance were used to research the soil habitat conditions and site conditions under different vegetation types so as to assess the relationships between soil habitat conditions and vegetation regeneration in Zhangye City, Gansu Province. The results showed that, according to the vegetation regeneration difficulty index, the vegetation regeneration difficulty was divided into four levels, [WTBX]i.e.[WTBZ] the level Ⅰ easy to regenerate vegetation (0-0.424), level Ⅱ with moderate difficult to regenerate vegetation (0.425-0.56), level Ⅲ with difficult to regenerate vegetation (0.57-0.774), and level Ⅳ with extreme difficult to regenerate vegetation (0.775-1). The factors restricting the vegetation regeneration in the city were mainly the soil moisture content and soil gravel content. The difficulties in regenerating vegetation were closely related to the vegetation types, soil conditions and habitat conditions. On the basis of the assessment, some suggestions were put forward for regenerating vegetation in Zhangye City based on the different difficulties.
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    Response of Populus euphratica Seedlings to Photosynthesis light  under Salt Stress
    LI Ju-Yan, ZHAO Cheng-Yi, YAN Ying-Yu, SHENG Yu, YU Bo, PENG Gang
    2014, 31 (4):  728-733. 
    Abstract ( 1252 )   PDF (1741KB) ( 857 )  
    As the dominant species of the riparian forests along the Tarim River in Xinjiang, northwest China, [WTBX]Populus euphratica[WTBZ] plays an important role in maintaining the functions of riparian ecosystem. Recent embankments along the river have altered the soil, water and salinity conditions of the riparian zones, which is expected to impact the survival and growth of [WTBX]P. euphratica[WTBZ] seedlings as well as the regeneration of the riparian forests. In order to assess the potential effects of these alterations on [WTBX]P. euphratica,[WTBZ] the photosynthesis of [WTBX]P. euphratica[WTBZ] seedlings under different soil salinity gradients was explored. The results indicated that the net photosynthetic rate [WTBX](Pn),[WTBZ] stomatal conductance [WTBX](Gs),[WTBZ] transpiration rate [WTBX](Tr)[WTBZ] and water use efficiency [WTBX](WUE)[WTBZ] of the seedlings were increased with the increase of the photosynthetically active radiation [WTBX](PAR)[WTBZ] in a range of 0-3 500 μmol•m-2•s-1, whereas the change of intercellular CO2 concentration [WTBX](Ci)[WTBZ] was reverse. Photosynthesis of seedlings was restrained, which was evidenced by the decrease of the mean values of [WTBX]Pn, Gs[WTBZ] and [WTBX]Tr[WTBZ] under the mild salinity stress (0.5 mol•L-1). However, the [WTBX]WUE[WTBZ] of seedlings was high to reduce water loss through regulating stomatal closure. Under severe salinity stress (2 mol•L-1), the Tr of seedlings was significantly decreased due to the insensitive stomatal regulation to light, and the average of [WTBX]Pn[WTBZ] was decreased by about 75%. With the increase of salinity, the maximal net photosynthetic rate [WTBX](P[WTBZ]nmax), lightsaturation point [WTBX](LSP),[WTBZ] dark respiration rate [WTBX](Rd)[WTBZ] and apparent quantum yield [WTBX](α)[WTBZ] of the seedlings were gradually decreased, but the light compensation point was gradually increased. The results suggested that the capability of light absorption, utilization and conversion of the seedlings was restrained under salinity stress.
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    Effect of Drought Stress on Germination and Physiological Properties of Phaseolus coccineus Seeds
    WANG Jing-Wei, JIN Xi-Jun, DU Wen-Yan, SHI Zhen-Sheng, ZHANG Yu-Xian
    2014, 31 (4):  734-738. 
    Abstract ( 1178 )   PDF (1595KB) ( 916 )  
    The germination and physiological indices of Phaseolus coccineus seeds were investigated under artificial drought stress using 5%, 10%, 15%, 20% and 25% polyethylene glycol solutions (PEG-6000). The results showed that the effects of moderate drought stress on the germination process, germination rate, germination index and vigor index of P. coccineus seeds were not significant, these seed germination indexes were inhibited with the increase of drought stress, and the higher the drought stress, the most significant the decrease would be. SOD, CAT and POD activities were increased at first and then decreased with the increase of drought stress, the maximum values of SOD and CAT occurred at 10% PEG, and that of POD at 15% PEG. The curves of MDA and Pro content were unimodal.
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    Dormancy and Germination of Iris halophila Seeds
    ZHUO Lu, GUAN Kai-Yun, LI Wen-Jun, BU Hai-Li-Qie-Mu·A-Bu-Du-Re-He-Man-
    2014, 31 (4):  739-743. 
    Abstract ( 1145 )   PDF (1024KB) ( 849 )  
    Iris halophila is an ornamental flower species distributed in arid regions, the germination percentage of its seeds is low, which causes a difficulty in its breeding, and the landscape application of this plant is severely constrained. The purpose of this study was to understand the dormancy ofI. halophila seeds through conducting the absorbent and germination experiments. The results revealed that 25/10 ℃ was the most suitable temperature for germination of I. halophila seeds, and a germination rate of 44.33% was attained; it was considered that the germination inhibitory substances in endosperm may be the main factor restricting the germination of I. halophila seeds; seed coat may mechanically restrict the release of inhibitory substances in endosperm; the seed germination percentage could be increased through scarification and removal of endosperm and GA3, and scarification would be the best way of improving the germination of I. halophila seeds.
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    Effects of Soil covering Thickness on Emergence Rate and Seedling Growth of Quercus wutaishanica
    WANG Juan-Ting, WANG Nai-Jiang, DANG Peng, ZHANG Ren-Fan, XI Shi-Hong
    2014, 31 (4):  744-749. 
    Abstract ( 1044 )   PDF (661KB) ( 996 )  
    In this study, the effects of soilcovering thickness and sowing time on the emergence rate and seedling growth of [WTBX]Quercus wutaishanica,[WTBZ] a kind of natural secondary forest on the Loess Plateau, were researched. The results were as follows: ① Soilcovering thickness affected significantly the emergence rate [WTBX](P<0.05),[WTBZ] the emergence rate was increased with the increase of soilcovering thickness and reached its maximum value when the soilcovering thickness was increased to 10 cm. The effect of soilcovering thickness on the seedling growth was not significant; ② The effect of sowing time on the emergence rate was significant when the soilcovering thickness was 0-3 cm [WTBX](P<0.05).[WTBZ] The emergence rate that the sowing time was on November 1 was higher than that on December 10 because of the temperature difference, and the emergence rates that the sowing time was on these two days were (11.9±1.2)%-(53.2±20.7)% and (1.5 %±0.8)%-(42.0±0.7)% respectively; the effect of sowing time on the seedling growth was not significant but the leaf area [WTBX](P<0.05).[WTBZ] Therefore, it could be concluded that soilcovering was advantageous for improving the emergence rate of [WTBX]Q. wutaishanica,[WTBZ] but its effect on the seedling growth was not significant.
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    Matching of Spectral Data of Typical Vegetation on Dune in the Horqin Sandy Land
    DUAN Rui-Lu, LIU Ting-Xi, ZHANG Sheng-Wei, DUAN Li-Min, TIAN Jing, WANG Zhao-Pu, TIAN Bo-
    2014, 31 (4):  750-755. 
    Abstract ( 1512 )   PDF (2304KB) ( 736 )  
    Spectral data are the joint affecting results of many factors, and there may be the “same objects with different spectra” or “different objects with the same spectra”. In this study, four common spectral matching algorithms, [WTBX]i.e.[WTBZ] the Minimum Distance (MD), Spectral Similarity Angle (SSA), Spectral Correlation Coefficient (SCC) and Spectral Information Divergence (SID), were used to carry out the matching analysis on the denoised spectral data of plants growing on sand dune in the Horqin Sandy Land. It was found that the minimum distance method could be used to distinguish the typical plant species on sand dune in the study area. On which a matching analysis of spectral derivative was carried out, it was found that the distinguishing effects of spectral similar angle and spectral correlation coefficient were significantly increased, and even a negative value of the matching degree of second derivative spectrum occurred. The band TM1, TM2, TM3 and TM4 of vegetation spectral data were selected to process, and it was verified that the band TM2 and TM4 could be used to improve the distingishing accuracy. After analyzing the basic information of single band with the statistically based analysis, it was found that the amount of information contained in a single band was in an order of TM1>TM4>TM2>TM3, and it was considered that the band TM4 should be the first choice to distinguish the plant species in the study area based on a comprehensive consideration of the highly overlapped spectral reflectance curve and the spectral matching results of single band of plant species.
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    Physiological Responses of Lycium ruthenicum  Murr. Seedlings to Drought Stress
    LI Yong-Jie, LI Jin, XU Ping, HE Hong-Wei
    2014, 31 (4):  756-762. 
    Abstract ( 1318 )   PDF (1645KB) ( 1149 )  
    The growth and physiological properties of Lycium ruthenicum Murr. seedlings under drought stress were studied so as to explore the defense mechanism of this plant species, reveal the mechanism of drought resistance in plants, and try to provide a theoretical basis for protecting, exploiting and utilizing the plant resources in the arid environment. L. ruthenicum Murr. seedlings were potted under four different soil moisture content levels, i.e. the optimal soil moisture content (CK), moderate drought stress (D1), moderate drought stress (D2), and severe drought stress (D3), which were controlled by weighing the soil and pots. The results were as follows: ① With increasing drought stress, the growth of plant height and base diameter, biomass and LMR of the seedlings were increased in treatment D1, but decreased in treatment D2 and D3; the RMR and root/shoot ratio were gradually increased in treatment D1 and D2, but decreased in treatment D3; ② The contents of Pro and soluble sugar were sharply increased in treatment D2 and D3; along with the drought stress time, the content of soluble protein was increased at first and then decreased; the content of MDA was increased at first, then decreased gradually, and increased again at last; ③ Along with the drought stress time, SOD activity was in an increase trend, the activities of POD and CAT were increased at first and then decreased. These results suggested that L. ruthenicum Murr. seedlings could reduce the water loss of aerial parts, increase the biomass of the roots to absorb more water, change the cell osmotic potential by accumulating the osmotic regulators to reduce the water loss within the cell and by regulating the growth and biomass allocation. Moreover, [WTBX]L. ruthenicum[WTBZ] Murr. can improve the activity of protective enzymes to weaken the role of membrane lipid peroxidation, and showed a strong drought tolerance.
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    Spatial Distribution Patterns and Type Structure of the Deserts in Xinjiang
    ZHANG Zhi-Wei, YANG Fa-Xiang, WU Ji-Long, ZHOU Jie, YIN Hui-Yan
    2014, 31 (4):  763-770. 
    Abstract ( 2223 )   PDF (2342KB) ( 1064 )  
    This paper was designed to compile the piece wise figures of deserts and their types in Xinjiang and to analyze the spatial distribution and structure of the deserts in Xinjiang based on the digital geomorphologic map (1∶1 000 000) and TM image data using Google Earth or GIS. The results were as follows: ① There are 577 desert fragments in Xinjiang, and they can be divided into 35 subareas. The deserts can be divided into six areas, i.e. the desert area in the Tarim Basin, desert area in the Junggar Basin, desert area in the Altay Mountains, west Junggar mountainous desert area, the Kunlun MountainAltun Mountain desert area, and Tianshan Mountain desert area; ② Area of the deserts in Xinjiang is 428 977.14 km2 and occupies a quarter (26.12%) of the total area of Xinjiang. Deserts are distributed widely in the plains, hilly regions and mountains. Spatially, the deserts are mainly distributed in the Tarim Basin and Junggar Basin. There is an obvious spatial heterogeneity of desert landscapes. The fragmentation degree of desert landscapes is high in the two large deserts in the Tarim Basin and Junggar Basin, and it is low in the two large basins but high in the mountainbasin ecotone; ③ There are the peculiar landforms dominated by dunes, longitudinal dunes, dunechains and sand ridges in Xinjiang, and the desert vegetation coverage is low.
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    Activity of Canis lupus in the Karamori Mountain Ungulate Nature Reserve Based on Trap Technique of Infrared Camera
    WANG Yuan, CHU Hong-Jun, HAN Li-Li, GE Yan, TAO Yong-Shan, BU Lan-
    2014, 31 (4):  771-778. 
    Abstract ( 1493 )   PDF (2617KB) ( 982 )  
    In this study, the activity of Canis lupus was monitored with trap technique of infrared camera in the Qiaomuxibai released area of Equus przewalskii in the Karamori Mountain Ungulate Nature Reserve in Xinjiang, China. It was found that the daily activity difference index (α) and diurnal activity index (β) of [WTBX]C. lupus[WTBZ] were quite different from different months (α: t=8.009, df=7, P<0.01; β: t=13.526, df=7, P<0.01, and β=0.45<13/24), which revealed that C. lupus is a species of nocturnal animal in the study area. The seasonal activity patterns of C. lupus during the period from 2011 to 2013 were obviously different (2011: χ2=13.087, [JP2]df=2, P=0.041 1; 2012: χ2=12.452, df=2, P=0.023 4; and 2013: χ2=18.998, df=2, P=0.032 6).[JP] It could be conclude that there were the differences in seasonal and annual activities of C. lupus in the study area.
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    Hg Contamination in the Vicinity of Tianye Industrial Zone in Xinjiang
    WANG Xin-Hua, PAN Xiang-Liang
    2014, 31 (4):  779-784. 
    Abstract ( 1583 )   PDF (1170KB) ( 793 )  
    Mercury (Hg) is a highly toxic pollutant to ecosystem and human health. In this study, Hg pollution and its potential ecological risk in the vicinity of Tianye PVC Factory in Xinjiang was investigated. The total Hg concentrations in air, water, soil and plant samples collected from the study area were analyzed by the RA-915+Zeeman mercury analyzer. The results showed that gaseous elemental mercury (GEM) concentrations were below the national standard in the Secondary Standard of Air and Environmental Quality. It was identified that the reservoir water quality was in class IV based on the total Hg concentration. The total Hg concentration in all soil samples was within the national standard in the Secondary Standard of Soil Environmental Quality. The total Hg concentration of rice was higher than the limit for national food safety standards, and that of onion, rape and corn was below the limit. The total Hg concentration of various species of fishes were within the national standards of food hygiene standard. The Hg concentration was in an order of carnivorous fishes>omnivorous fishes>plants of predatory fish, and also an order of fish without scales>fish with scales. The results revealed that the study area was slightly polluted by Hg, and there was a potential ecological risk.
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