Table of Content

15 May 2013, Volume 30 Issue 3 Previous Issue    Next Issue

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Characteristics of the Eco-geographical Pattern in Arid Land of Central Asia CHEN Xi, JIANG Feng-Qing, WANG Ya-Jun, LI Yao-Ming, HU Ru-Ji 2013, 30 (3):  385-390.  Abstract ( 2318 )   PDF (6002KB) ( 2211 )   The arid land in central Asia is the largest dry area located in the temperate and warm temperate zone of northern hemispheric earth.It is also the region characterized by very fragile ecology and environment and with plentiful natural and energy resources.It is necessarily that to reveal deeply the regional regulatory of eco-geographical pattern in order to meet the demands of ecological safety, rational utilization of natural and energy resources and social sustainable development.Thus, in this paper the evolution process of eco-geographical system in arid land of the central Asia is discussed in view of genetics and by using method of systemic theory.The main features of eco-geographical system is analyzed and the eco-geographical pattern is outlined according to regional geological geomorphologic, and climatic conditions and hydrological circulation process in arid land of the central Asia We recognize that the mountainous forest grassland-plain oasis in basins which is co-existed with desert constitutes a complex and complete eco-geographical system.This system is one of the most obvious and basic natural eco-geographical essence and characterizes the eco-geographical pattern in arid land of the central Asia.Obviously, to thoroughly understand this eco-geographical pattern will be of vital theoretic and practical importance to action on regional ecological restoration and reconstruction.The results of this paper can play an important role in formulating the strategy on sustainable social and economical development in arid land of central Asia. References | Related Articles | Metrics

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Water Problems Based on Spatial Matching Patterns of Water and Land Resources in Central Asia YAO Hai-Jiao, ZHOU Hong-Fei, SU Feng-Chun 2013, 30 (3):  391-395.  Abstract ( 1533 )   PDF (1009KB) ( 1395 )   Central Asia is one of the most prominent areas with serious ecological and environmental problems caused by utilization and development of water and land resources. The method of Gini coefficient and the data of water resources volume per unit area of cultivated land were used to analyze the matching relationship between water and land resources in Central Asia. Results showed that the spatial matching status of water and land resources is good when the five countries in Central Asia are as a unity. Through water transfer, a balance of water and land resources in Central Asia can be achieved. However, the matching level of water and land resources is quite different from different countries in Central Asia, and it is higher in the upstream countries than that in the downstream countries. Therefore, water volume is not the only water problem in Central Asia, but the rational redistribution and utilization of water resources among the countries there is the key water problem, especially in the international drainage basins and among the upstream and downstream countries. References | Related Articles | Metrics

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Climatic Characteristics in Central Asia Based on CRU Data HUANG Qiu-Xia, ZHAO Yong, HE Qing 2013, 30 (3):  396-403.  Abstract ( 2985 )   PDF (2751KB) ( 2868 )   Based on the CRU data in Central Asia during the period of 1971—2000, in this paper the method of linear regression was used to analyze the climate change in Central Asia in recent 30 years. The results showed that the desert regions in Turkmenistan and Uzbekistan were the aridest areas with the highest temperature in Central Asia. Precipitation in Tajikistan and Kyrgyzstan in winter and spring was higher than that in summer and autumn, and temperature range was relatively low. In Kazakhstan, precipitation occurred mainly in summer, and it decreased from the west to the east; the range of temperature was high, and it was warmer in the west than that in the east. The annual range of temperature in Central Asia was low. There was a significant difference of climate between Xinjiang of China and the five countries in Central Asia, precipitation in Xinjiang occurred mainly in the Tianshan Mountains and in summer, where the warming trend was obvious, and the change trend of maximum and minimum temperature was opposite to that in the western part of Central Asia. References | Related Articles | Metrics

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Spatiotemporal Change of Water Reserves in the Tianshan Mountains, Xinjiang Based on GRACE XU Min, YE Bai-Sheng, ZHAO Qiu-Dong, WANG Jian 2013, 30 (3):  404-411.  Abstract ( 2539 )   PDF (2783KB) ( 1735 )   Change of the volume of water reserves in the Tianshan Mountains was analyzed using the monthly gravity field data derived from GRACE satellite with Gaussian filter during the period from 2003 to 2010, and the spatial resolution was 1°×1°. Trend analysis was used to analyze the spatiotemporal variation trend of water reserves in the Tianshan Mountains in recent 8 years based on the monthly precipitation data observed by 31 state meteorological stations. Results showed that there was a significant spatial variation of water reserves in the Tianshan Mountains, the volume of water reserves in the eastern and western parts of the mountains was higher than that in the central part. Temporally, there was an obvious seasonal variation of water reserves and precipitation, and their change trends were similar. The growth of water reserves in the mountains was negative during the period from January to March, its minimum value, -21.7 mm•a-1, occurred in February. The growth of water reserves was positive during the period from April to December, and its maximum value, 29.9 mm•a-1, occurred in November. However, the volume of water reserves in the Tianshan Mountains was holistically in a decrease trend during the period from 2003 to 2010, it was decreased by 13×108 m3 in recent 8 years, and its average monthly decrease was 4.8 mm. Reduction of water reserves in the Tianshan Mountains was mainly caused by climate warming, aggravation of glacier melt and increase of the volume of irrigation water and domestic water in the piedmont oases. References | Related Articles | Metrics

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Spatiotemporal Variation of Groundwater Depth in Ganzhou District in Middle Reaches of the Heihe River Basin YAN Yun-Xia, WANG Sui-Ji, YAN Ming, HE Li 2013, 30 (3):  412-418.  Abstract ( 1323 )   PDF (2481KB) ( 1127 )   Temporal variation of groundwater depth in 4 groundwater-level monitoring wells in Ganzhou District of Gansu Province in middle reaches of the Heihe River Basin was analyzed. Based on the similarity of groundwater recharge sources, temporal variation trend of groundwater depth and proximity of the locations of groundwater-lever monitoring wells, Ganzhou District was divided into four subregions. Groundwater level in subregion Ⅰ was in a drawdown with a big fluctuation, but it was in a slight increase after 2001; it was in a continuous drawdown in subregion Ⅱ; it was in a slow drawdown in subregion Ⅲ before implementing the water redistribution project but in a sharp drawdown after implementing the project; it was increased at first and then in a drawdown in subregion Ⅳ. References | Related Articles | Metrics

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Change of the Lakes in the Qiangtang Nature Reserve LI Lin, YANG Xiu-Hai, ZHA Xi-Yang-Zong, ZHAO Wen, LA Ba-Zhuo-Ma 2013, 30 (3):  419-423.  Abstract ( 1869 )   PDF (1434KB) ( 974 )   Based on the MSS data in the 1970s, TM data in the 1990s and ETM data at the beginning of the 21st century in the Qiangtang Nature Reserve in Tibet, in this paper the area and spatiotemporal variation of the lakes larger than 1 km2 in the nature reserve were interpret with remote sensing analysis. The results show that the lakes in the Qiangtang Nature Reserve were in a shrinkage during the period from 1975 to 1990, their number was decreased from 388 to 277, their total area was reduced from 6 603.3 km2 to 5 539.7 km2 (reduced by 16.1%), but thereafter until 2000, area of the lakes was enlarged dramatically. Number of the lakes was increased by 164 and to 441, total area of the lakes was enlarged to 9 652.2 km2 and by 4 112.5 km2 (enlarged by 74.2%) compared with that in 1990. Regionally, change of the lakes in the east was significantly higher than that in the west. The average daily and monthly temperature, average monthly maximum and minimum temperature, monthly precipitation and evaporation at 6 meteorological stations including Shiquanhe, Gaize, Bange, Shenza, Naqu and Anduo were analyzed, and the results revealed that the temperature at the 6 stations was increased; precipitation was significantly increased in the east, and its change was not significant in the west; annual evaporation was in a decrease trend. It is considered that precipitation was the most important factor affecting the change of the lakes, and then temperature and evaporation. References | Related Articles | Metrics

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Effect of Drip Irrigation with Brackish Water with Different Salinities on Soil Alkali-hydrolyzable Nitrogen Content in Rhizosphere of Ziziphus jujuba Trees LI Fa-Yong, WANG Xing-Peng, LIN Jie, LI Ning 2013, 30 (3):  424-429.  Abstract ( 1282 )   PDF (1194KB) ( 841 )   This paper analyzed the effect of drip irrigation with brackish water with different salinities on the content of soil alkali-hydrolyzable nitrogen in rhizosphere of Ziziphus jujuba trees based on the experiment of irrigation with mixed salty water and fresh water. The results showed that the content of soil alkalihydrolyzable nitrogen in rhizosphere of Z. jujuba trees was increased with the increase of salinity of irrigation water when the migration and transformation time of soil alkali-hydrolyzable nitrogen was the same. The average value of soil alkali-hydrolyzable nitrogen content was increased at first and then decreased with the migration and transformation time of soil alkalihydrolyzable nitrogen when the salinity of irrigation water was the same. Under the same salinity of irrigation water, the change extent of soil alkali-hydrolyzable nitrogen content was in an increase trend, but the change rate was in a decrease trend. Based on analyzing the effect of irrigation brackish water with different salinities on soil alkali-hydrolyzable nitrogen content, the quantitative relationships among the salinity of brackish water and the migration and transformation time, average content, change extent and change rate of soil alkalihydrolyzable nitrogen were developed, and the regression equations were also derived in this study. References | Related Articles | Metrics

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Dynamic Change of Soil Respiration in Haloxylon ammodendron Community in Southern Edge of Junggar Basin in Snowmelt Season XIE Ji-Ping, ZHONG Wen-Zhao, HUANG Gang, LI Yan, WU Lin-Feng 2013, 30 (3):  430-437.  Abstract ( 1635 )   PDF (1284KB) ( 1084 )   Snowmelt affects highly the change of soil moisture content and temperature in topsoil in snow thawing season, and hence affects soil respiration in temperate arid land. In snow thawing season in early spring 2012, a carbon flux chamber was used to observe the dynamic change of soil respiration in Haloxylon ammodendron community in southern marginal zone of the Gurbantonggut Desert. The results showed that the variation of soil respiration rate was significant and ranged from 0.2 to 1.2 μmol•m-2•s-1. In snow thawing season, the mean soil respiration rate was increased at first and then decreased, and its maximum value was decreased with the decrease of soil moisture content. Soil respiration under bushwood was significantly higher than that out of the bushwood, and its variation under and out of the bushwood was similar. There was a significant correlation between soil moisture content and maximum soil respiration in snow thawing season, and also a significant correlation between soil temperature and soil respiration at daily scale. The study results revealed that there was a stimulating effect of snow thawing on soil respiration, and the change of snow cover in early spring affected significantly soil respiration in the Gurbantonggut Desert. References | Related Articles | Metrics

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Spatial Variation of Soil Moisture Content in the Dune-meadow Ecotone in the Horqin Sandy Land WANG Hai-Yan, LIU Ting-Xi, WANG Li, WU Yao, WANG Tian-Shuai, TONG Xin 2013, 30 (3):  438-443.  Abstract ( 1523 )   PDF (2471KB) ( 1120 )   The spatial distribution of soil moisture content is complex in the Horqin Sandy Land with dunemeadow landscape features, because of various landforms and different types of land use. The statistic theory and methods were used to study the spatial variation and distribution of soil moisture content through careful investigation, sampling and test analysis. The results showed that, at horizontal direction of the study area, soil moisture content in meadows was much higher than that in sand dunes. As for the meadows, the better the vegetation grew, the higher the soil moisture content and water retention capacity would be. It was contrary in the areas with sand dunes, soil moisture content and soil water retention in mobile dunes covered by sparse vegetation was higher than that in semi-fixed and semi-mobile dunes or fixed dunes. Vertically, there was a high fluctuation of soil moisture content in soil layer of 0-40 cm in depth in meadows with high and low vegetation coverage or in cropland, and soil moisture content in soil layer of 40-160 cm in depth was increased with the increase of soil depth. Soil moisture content was slightly increased with the increase of soil depth in mobile dunes, semi-mobile dunes and fixed dunes. In woodland, fallow land and cropland (in sandy land), the variation of soil moisture content was moderate. Spatially, soil moisture content was high in the central and eastern parts of the study area and decreased southward and northward. References | Related Articles | Metrics

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Total Soil Salinity in Artificial Forest in the Junggar Basin Based on Hyperspectrum CHEN Dong-Qiang, WANG Rang-Hui 2013, 30 (3):  444-448.  Abstract ( 1788 )   PDF (1117KB) ( 1001 )   With the rapid development of hyperspectral remote sensing, it is feasible to quantitatively investigate the important chemical components in soil. In this study, the values of NIR-Visible spectral reflectance of soil samples collected from the Junggar Basin in Xinjiang, China were measured with an ASD Pro FieldSpec3 hyperspectral meter so as to predict the total soil salinity based on the spectral reflectance of soil, and provide a theoretical basis for monitoring soil salinization. The Pearson correlation coefficient analysis was used to estimate the correlation between total salinity and spectral reflectance of soil. The results showed that there was a good correlation between soil spectral reflectance and total soil salinity. The highest correlation coefficient between second derivative of soil spectral reflectance and total soil salinity was 0.806, and the minimum rootmeansquare error was 1.508. Through the multiple statistics regression analysis based on spectral reflectance, the performance of inversion model of total soil salinity at wavelengths of 1 130 nm, 1 430 nm and 1 930 nm was good, these three wavelengths could be used to develop a regression equation for inversing the values of total soil salinity. References | Related Articles | Metrics

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Spatial Distribution and Evolution of Climatic Aridity in Desert  Steppe in Inner Mongolia in Recent 50 Years HAN Fang, LIU Peng-Tao, NIU Jian-Ming, WUlan Bater, ZHANG Qing, ZHANG Jing 2013, 30 (3):  449-456.  Abstract ( 2277 )   PDF (1706KB) ( 1249 )   According to the average daily temperature and daily precipitation data from 11 meteorological stations in desert steppe in Inner Mongolia during the period of 1961—2010, the temporal and spatial variation of climatic aridity in the steppe in recent 50 years was analyzed using the improved formula of Selianinov AI and ArcGIS software. The results are as follows: ① The average aridity and aridity degree increased gradually from the southeast to the northwest; ② Under the temperature increase and precipitation decrease in the steppe, the aridity index was in an increase trend in most regions except in the centralwestern region, that is the climatic drying trend in desert steppe in Inner Mongolia was significant; ③ According to the analyzed results of aridity, the 1970s was a relatively wet decade, and the aridity increased significantly in the early 21st century. The drought area was enlarged year by year, it was enlarged for nearly three times up to the early 21st century, and the drought trend was significant; ④ The 4.0-contour of aridity was gradually shifted towards the typical steppe southeastward. The 1960s was regarded as a starting decade, a relatively low variation occurred before the 1990s, but a significant variation occurred from the early 21st century. Moreover, the variation and the spatial shift amplitude were high in the east of the study area, and they were relatively low in the west. References | Related Articles | Metrics

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Effect of Abnormal East Asia North Wind on Spring Precipitation in the Eastern Region of Northwest China ZHAO Hong-Yan, YANG Yu-Feng, GUO Jun-Qin, WANG Xing, ZHAO Qing-Yun 2013, 30 (3):  457-461.  Abstract ( 1449 )   PDF (1185KB) ( 937 )   The values of spring East Asia north wind index were calculated based on the data of NCEP/NCAR reanalyzed monthly 500-hPa height field during the period from 1961 to 2010 and of monthly precipitation at 170 meteorological stations in Qinghai, Gansu and Shaanxi provinces and NingxiaHui Autonomous Region in the eastern region of northwest China. The history change of spring precipitation and the relationship between the decadal variation of East Asia north wind index and the spring precipitation in northwest China were analyzed. The results showed that, bordered by the Yellow River, precipitation was in an increase trend in the regions west from the Yellow River but a decrease trend in the regions east from the river. The precipitation decrease amplitude was significantly higher than the increase amplitude. Especially in recent 20 years, the precipitation decrease was more and more significant in the vast region east from the Yellow River, and the drought trend was obvious. Precipitation, however, was in an increased trend in south Qinghai Province and the Hexi Corridor in Gansu Province. The spring East Asia north wind increased gradually during this period, especially after the mid1990s. Further analysis showed that, when the spring East Asia north wind was strong, precipitation was decreased in most areas of the eastern region of northwest China except in south Qinghai Province. So it could be concluded that the abnormal strong spring East Asia north wind could cause a decrease of precipitation and an aggravation of drought in the regions east from the Yellow River. References | Related Articles | Metrics

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Effects of Parameterized Physical Process of WRF Model on Simulation of Precipitation in the Heihe River Basin ZHU Qing-Liang, JIANG Hao, WANG Ke-Li, LUO Xin-Ping 2013, 30 (3):  462-469.  Abstract ( 1906 )   PDF (2512KB) ( 1665 )   A rainfall event in the Heihe River Basin was taken as an experimental case, and the mesoscale WRF3.1 was applied to study the sensitivity of different parameterized schemes to rainfall simulation. Effects of the microphysics, cumulus convection, land surface processes and the planetary boundary layer in the WRF parameterized schemes on the sensitivity of rainfall simulation in the Heihe River Basin were discussed, and the simulated results were validated with the observation data from 12 meteorological stations in the basin. The results showed that there was no single parameterized scheme to perform well in the simulation, and a combination of various parameterized schemes would be better. The results suggested that the center, value, distribution and extent of rainfall could be simulated well if the Mellor-Yamada-Janjic planetary boundary layer parameterized scheme and the Noah land surface process parameterized scheme were applied simultaneously. The results also suggested that the results simulated with Ferrier scheme were better than those with WSM3, WSM5 and Lin schemes. The sensitivity of cumulus convection parameterized scheme to the rainfall simulation was significantly lower than that of other schemes. References | Related Articles | Metrics

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An Infrequent Snowstorm Weather over the Central Tianshan Mountains in Xinjiang AN Dong-Liang, ZHAO Jun-Rong 2013, 30 (3):  470-476.  Abstract ( 1520 )   PDF (2705KB) ( 765 )   An infrequent snowstorm occurred over a zone from Usu to Shihezi in the central part of northern piedmont of the Tianshan Mountains, Xinjiang, China during February 22-23, 2010. The snowstorm resulted in a serious economic loss, especially in facility agriculture, traffic, electric power and peopl[JP8]e’[JP]s daily life. In this paper, the NCEP/NCAR 1°×1° 6 h reanalysis data and the synoptic diagnostic method were used to analyze the circulation and physical quantity of the infrequent snowstorm weather. The results showed that the snowstorm occurred under an interaction of shortwave of strong frontal zone in periphery of the vortex and the south branch trough. The vertical structure of low-level convergence and upper-level divergence promoted the air rise and the aggregation and uplift of low-level warm air, and provided the trigger conditions of energy for snowstorm formation, occurrence and development. The snowstorm intensity and duration was positively correlated with the intensity, thickness and relative humidity of ascending motion, which is an indication for estimating the occurring time and spatial distribution of snowstorm in the study area. References | Related Articles | Metrics

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Variation of Wind Erosivity in the Wind Erosion and Wind-water Erosion Regions in the Loess Plateau JIANG Chong, CHEN Ai-Fang, YU Xiao-Yong, WANG Fei, MU Xing-Min, LI Rui 2013, 30 (3):  477-484.  Abstract ( 2400 )   PDF (1809KB) ( 1021 )   In this paper, the climatic factor index of wind erosion, climate trend rate, Pettitt sharp change point detection and Morlet wavelet transform were used to analyze the spatial distribution, spatiotemporal variation, sharp change and periodicity of wind speed as well as their effects on climatic factor index of wind erosion based on the data from 30 meteorological stations in the wind erosion and windwater erosion regions in the Loess Plateau during the period from 1961 to 2010. The results are as follows: ① The multi-year average wind speed was 2.2 m•s-1, and it was relatively high in most regions in Inner Mongolia and Ningxia Hui autonomous regions, but low in north Shaanxi Province, northwest Shanxi Province, east Gansu Province and some areas in Qinghai Province. Wind speed was the highest in spring, and then in summer, autumn and winter, it was holistically in a decrease trend in recent 50 years, lowest in the 1970s but highest in the 2000s; ② A sharp change of wind speed occurred at 83% stations, the holistic sharp change in the study area occurred in 1982, and the seasonal sharp change was similar to the annual one; ③ Three times of alternant change of wind speed occurred in recent 50 years, the wind speed was high during the periods of 1961—1977 and 1995—2010 but low during the period of 1977—1995, seasonal change of wind speed was similar, and the wind speed would be still low in near future; ④ The spatial distribution and spatiotemporal change trend of climatic factor index of average annual wind erosion was similar to the change of wind speed; ⑤ The climatic factor index of wind erosion was correlated negatively with relative humidity and precipitation, thus the increase of precipitation or relative humidity could restrain wind erosion; there were positive correlations among the climatic factor index of wind erosion and the potential evaporation, drought index and wind speed. The increase of wind speed, drought index, temperature and evaporation could promote wind erosion. References | Related Articles | Metrics

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Relationship between Number of Sunspots and Rainfall in Xi’an in Summer and Autumn ZHANG Xiao-nan, SHI Xing-Min, YANG Shang-Ying 2013, 30 (3):  485-490.  Abstract ( 1589 )   PDF (2794KB) ( 972 )   Based on the data of rainfall in Xi’an and the number of sunspots during the period from 1960 to 2007, a time series of precipitation was analyzed using the simple linear regression and Mann-Kendall test as well as other statistical methods. The wavelet analysis was used to study the relationship between the number of sunspots and rainfall in summer and autumn. The results showed that the proportion of rainfall in summer and autumn  was about 80% of annual precipitation in Xi’an. Rainfall in Xi’an in summer was in an increase trend, but that in autumn was in a decrease trend. Precipitation in Xi’an was closely related to the number of sunspots, and the maximum value of precipitation occurred when the maximum number of sunspots occurred or around 2 years. There was a 10-year periodic fluctuation of rainfall in summer, and also a 9-year periodic fluctuation of rainfall in autumn. There was a high correlation between the number of sunspots and precipitation at 9-year scale, a positive correlation between rainfall in summer and the number of sunspots with one or two-year difference, but a negative one between rainfall in autumn and the number of sunspots with one or two-year ahead of time. References | Related Articles | Metrics

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Edaphon Faunas and Their Implications in Salinized Soil in the Ningxia Yellow River Irrigated Area LI Feng-Xia, WANG Xue-Qin, GUO Yong-Zhong, XU Xing, KE Ying 2013, 30 (3):  491-496.  Abstract ( 1528 )   PDF (737KB) ( 1134 )   n order to know the dynamic change of soil edaphon faunas and the effect of soil chemical properties on edaphon in salinized soil at different degradation degrees, the distribution and seasonal dynamic change of edaphon, soil chemical properties, nutrient content and the correlation between edaphon and soil properties at different salinization levels in Huinong, Ningxia Hui Autonomous Region were studied using the plate dilution method and the conventional measurement of soil chemical properties. The results showed that, in the region with salinized soil, the pH value and basicity of slightlysalinized soil was the highest with the increase of soil salinization level, and they were higher in soil layer of 20-40 cm in depth than in soil layer of 0-20 cm. Soil nutrient content, bacteria, fungi and actinomycetes were all in a decrease trend with the severity increase of soil salinization, they were in an order of slightlysalinized soil>moderatelysalinized soil>severelysalinized soil, and they were significantly higher in soil layer of 0-20 cm than in soil layer of 20-40 cm. Temporally, the number of bacteria, fungi and actinomycetes was in an order of June>August>September. There was a significant correlation between edaphon faunas and soil nutrient content. There were the significant or highly significant positive correlations among the numbers of bacteria, fungi and actinomycetes and the contents of soil organic matter, total nitrogen, total phosphorus, alkalihydrolyzable nitrogen, available phosphorus and available potassium (P<0.05 or P<0.01) except the situation with the total potassium content. Therefore, the values of soil edaphon faunas can be regarded as the biological indexes to evaluate soil improvement level and evolution of soil salinization.　 References | Related Articles | Metrics

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Effect of ABA on Antioxidant Enzyme Activity of Cynodon dactylon with Different Cold Resistance under Low Temperature SUN Zong-Jiu, LI Pei-Ying, A Bu-Lai-Ti, SUN Qing-Ling 2013, 30 (3):  497-504.  Abstract ( 1692 )   PDF (3447KB) ( 838 )   Taking cold-sensitive bermudagrass (common bermudagrass and coastal bermudagrass) and cold-resistant bermudagrass (Xinnong No.1 and Kashgar bermudagrass) as the test materials, the effect of ABA (0 mg•L-1,5 mg•L-1, 15 mg•L-1 and 25 mg•L-1) on relative electric conductivity (EC), malondialdehyde content (MDA), superoxide dismutase activity (SOD), catalase activity (CAT) and peroxidase activity (POD) of leaves under 4 ℃ for 24 and 72 hours were studied. The results showed that the EC and MDA of bermudagrass were increased compared with the situation of CK2 (water spray and cultivation under room temperature) regardless of spraying ABA or not. But compared with the situation of CK1 (water spray and cultivation under 4 ℃), spray of ABA could induce the decrease of EC and MDA of bermudagrass, promote the increase of SOD activity, CAT activity and POD activity, protect the integrity of membrane system, and enhance the adaptation to low temperature. After carrying out a comprehensive analysis, it was considered that the suitable ABA concentration for cold-resistant bermudagrass was 15 mg•L-1, that for cold-sensitive bermudagrass was 5 mg•L-1under the consideration of adapting low temperature. With prolonging the time of low temperature, the increase rate of SOD activity and the decrease rate of MDA of cold-resistant bermudagrass were obviously higher than that of coldsensitive bermudagrass, which revealed that the difference of SOD activity was one of the reasons to cause the difference of cold resistance. References | Related Articles | Metrics

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A Revision of Pohlia Hedw.(Mielichhoferiaceae,Musci) in Xinjiang, China LIU Yong-Ying, MAI Mai-Ti-Ming-?Su-Lai-Man, ZHAO Jian-Cheng, CHEN Xiao-Ping 2013, 30 (3):  505-511.  Abstract ( 3442 )   PDF (2401KB) ( 1001 )   The phylogenetic position of the genus Pohlia Hedw. is uncertain yet. Traditionally, the genus was placed in the subfamilies Bryoideae or Pohlioideae of generalized family Bryaceae (sensu lato). Then it was accommodated into family Mniaceae or Mielichhoferiaceae. In this paper, a revision of Pohlia in Xinjiang Uygur Autonomous Region, China was provided based on the specimens and references. Two species, P. proligera and P. camptotrachela were deleted from the moss checklist of the region. Additions to two mosses in Xinjiang, P. longicollis and P. crudoides var. revolvens. P. minor were reduced to a synonym as P. elongata var. greenii. Pohlia in Xinjiang, including 8 species and 2 varieties, was newly updated in the checklist. About one third species of the total in China were distributed in Xinjiang. The diagnostic characteristics and habitats for the species were provided in the paper. The voucher specimens were deposited in the herbarium of Hebei Normal University (HBNU), herbarium of Xinjiang University (XJU), and Chinese National Herbarium, Chinese Academy of Sciences (PE). References | Related Articles | Metrics

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New Records of Cosmarium] Cord. in Xinjiang Akbar Yimit,Hasan Abdurehim, WANG Zhi-yong, Mamtimin Sulayman, LV Hai-ying 2013, 30 (3):  512-515.  Abstract ( 2080 )   PDF (644KB) ( 1087 )   In this study, some algal specimens were collected from the southern part (43°20′～43°50′ N, 88°19′～88°54′ E, 1 104～1 148 m a. s. l.) of the Dabancheng rift valley in Urumqi, Xinjiang, China in June and August 2010, where many wetlands including rivers, swamps, lakes and ponds are distributed. Desmids are very rich in the study area. By referring to a lot of literatures and using the methods of traditional identification, it was found that 6 species, i.e. Cosmarium bioculatum, C. depressum, C. ochthodes, C. pachydermum, C. punctulatum and C. rectangular, were reported for the first time in Xinjiang. In addition, the morphological characteristics of species identification were described. These new records would enrich the study data of Cosmarium in Xinjiang. References | Related Articles | Metrics

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Phylogenetic Relationship of Amygdalus ledebouriana Schlecht and Its Sibling Species in Xinjiang JIANG Feng-Qin, PAN Bo-Rong, YIN Lin-Ke, LIU Bin, LI Yan 2013, 30 (3):  516-519.  Abstract ( 1457 )   PDF (802KB) ( 1016 )   Amygdalus ledebouriana Schlecht (wild almond) is not only one of the rare wild plant resources, but also an endangered plant species. A. ledebouriana is only distributed in Xinjiang in northwest China. Chloroplast encoding intergenic genes (matK gene sequence) of A. ledebouriana and its sibling species were sequenced to investigate the phylogenetic relationship of wild almond, cultivated almond and the sibling species. Genetic relationship was inferred from the analysis of interspecific genetic distance based on Kimur[JP8]a’[JP]s twoparameter model and the neighborjoining (NJ) phylogenetic tree. The preliminary results indicated that there was a closer genetic distance between A. ledebouriana and A. mongolica and between A. ledebouriana and A. triloba, and a further genetic distance between A. ledebouriana and cultivated almond and between A. ledebouriana and the species of subgenus Amygdalus (A. persica, A. persica var. compressa and A. davidiana). Cultivated almond was more closely related to A. persica, A. persica var.compressa and ]A. davidiana than to the three species of almond, i.e. A. ledebouriana, A. mongolica and A. triloba. References | Related Articles | Metrics

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Long-term Dynamic Change of Helicoverpa armigera (Hübner) Population in Bt Cotton-growing Areas in South Xinjiang ZHANG Juan, MA Ji-Hong, LU Yi, WANG Pei-Ling, LI Xian-Chao, Lv Zhao-Zhi 2013, 30 (3):  520-526.  Abstract ( 1708 )   PDF (1208KB) ( 1214 )   Transgenic cotton has been engineered to produce insecticidal toxins from [WTBX]Bacillus thuringiensis (Bt) to resist cotton bollworms, [WTBX]Helicoverpa armigera (Hübner) has been commercially cultivated in China since 1997, and it has been intensively planted in Xinjiang fore more than 10 years, where cotton was cultivated in large area, and the crop systems were quite different from other areas. Therefore, it was suspected that the current results about the impact of Bt cotton planting on the seasonal population patterns of cotton bollworms may not reflect the actual situation in Xinjiang. The monitoring of cotton bollworms with light trapping was carried out in a high Bt density region in Markit County and in a low Bt density region in Awat County, Xinjiang during the period from 1999 to 2010. The analyzed results indicated that the population size of cotton bollworms was decreased only in the high Bt density region, but the change in the low Bt density region was not significant. There was a significant negative correlation between the percentage of Bt cotton planting and the light-trapped H. armigera moths. The population size of H. armigera moths of all three generations was decreased with the time of planting Bt cotton, the population size and light-trapped moths of the second generation were dramatically decreased compared with those of the overwinter and first generations, and the relative abundance of the second generation was also decreased gradually. These results demonstrated that cotton bollworm population was suppressed by high Bt density cultivation at present, especially for the second generation. References | Related Articles | Metrics

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Willingness to Pay of Urban and Suburban Households in Beijing for an Ecological Project in the Surrounding Areas MA Hua, LIU Hui, GONG Ya-Zhen, JIN Jian-Jun, MAO Xian-Qiang 2013, 30 (3):  527-533.  Abstract ( 1570 )   PDF (1086KB) ( 913 )   Contingent valuation method with dichotomous choice elicitation questions was used to estimate the willingness to pay (WTP) of urban and suburban residents in Beijing to the improved ecological services provided by the Beijing and Tianjin Sandstorm Source Control Project (BTSSCP). The results are that the mean WTP of residents in Beijing was 17.35-39.92 yuan RMB per household per month in 5 years; the total WTP of the benefited residents was less than the cost of the project; age, income and education level were the key factors affecting the respondents’ decision that whether they participated in the market, among which income and education level were more significant to affect suburban residents’participation decision. WTP was significantly related with the residents’income and household size. Although there was a difference of WTP between urban and suburban residents, the proportions of residents’ WTP in their income was similar, i.e. 0.28%-0.70% and 0.36%-0.65% respectively. References | Related Articles | Metrics

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Tracing Paleoenvironment Changes with Cosmogenic Nuclides 10Be and 26Al ZHAO Guo-Qing, ZHANG Li, WU Zhen-Kun, XIAN Feng, KONG Xiang-Hui 2013, 30 (3):  534-540.  Abstract ( 1778 )   PDF (1218KB) ( 1105 )   Cosmogenic nuclides 10 Be and 26Al have been widely applied to trace the paleoenvironment changes and the evolution of landforms during the Quaternary Period because of their unique formation mechanism, stable geochemical properties and long radioactive half-life. In this paper, the formation mechanism of 10Be and 26Al, application of atmospheric cosmogenic 10Be, basic principles of 10Be and 26Al dating, affecting factors and considerations in field sampling and laboratory test of 10Be and 26Al were discussed. The application of 10Be and 26Al in tracing the paleoenvironment changes was introduced so as to provide a useful reference for researching cosmogenic nuclides of 10Be and 26Al in geoscience and Quaternary geology in the future. References | Related Articles | Metrics

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Review of the Studies about the Latest Dried-up Time of the Lop Nur Lake in Recent 100 Years DUAN Han-Ming, AIlishir Kurban, ZHANG Yan, Abdumijit Ablekim 2013, 30 (3):  541-549.  Abstract ( 2125 )   PDF (1598KB) ( 1034 )   Dried-up of the Lop Nur Lake is an important event of environmental change in the arid zone of Central Asia, but scientists have not reached an agreement on the latest driedup time since the lake was submerged in 1921. After defining some relevant concepts and limiting the spatiotemporal range of the study object, in this paper the defects and doubts of present main viewpoints were analyzed one by one, and the change process and trend of the Lop Nur Lake surface as well as its water sources since the 1930s were also analyzed through comparing the relevant bibliography and re-interpreting the remote sensing images. Results indicated that the latest submergence of the Lop Nur Lake occurred in 1962, so the latest driedup of the lake maybe occurred in winter that year or not later than next summer. Climate was so arid in the study area that the lake changed frequently between expansion and shrinkage since the 1930s. Human activities including farming and damming resulted in the final driedup of the lake. References | Related Articles | Metrics

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Depositedsand Volume of High Vertical Sand Barrier under Different Stacking Modes KANG Xiang-Guang, LI Sheng-Yu, WANG Hai-Feng, LEI Jia-Qiang, XU Xin-Wen 2013, 30 (3):  550-555.  Abstract ( 1798 )   PDF (1074KB) ( 1120 )   In order to understand the nylon sand resistance nets for catching sand, the different stacking modes of nylon sand resistance nets were taken. In this study, three stacking modes of high vertical sand barriers were designed, and the stacking positions were designed separately on windward slope and leeward slope as well as at sand resistance nets. The distance between the stacked nylon sand resistance nets and the sand barriers and their length on both windward slope and leeward slope were the same, height of the nets was half of the sand barriers, and the stacked nylon sand resistance nets were higher than the nylon sand barriers. The sand barriers 1.2 m in height were selected to stack, and the stacking distance to the sand barriers was about 45 cm. The results are as follows: ① The depositedsand volume of the different stacking modes of high vertical sand barriers was different, and it was in an order of sand resistance nets>windward slope>leeward slope; ② The depositedsand volume of the three stacking modes was continuously increased with the increase of stacking sand resistance nets; ③ The sand resistance cost of the three stacking modes per unit volume was changed with the increase of stacking sand resistance nets: it was continuously decreased on windward slope and for sand resistance nets and stabilized finally; it was increased at first, then decreased and stabilized finally on leeward slope. The sand resistance cost per unit volume was in an order of resistance sand net References | Related Articles | Metrics

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The Environmental Kuznets Curve in Xi’an LI Hong-Yan, LI Jing, ZHANG Dong-Hai, CHEN Shan-Shan 2013, 30 (3):  556-562.  Abstract ( 1684 )   PDF (2190KB) ( 928 )   In this study, the statistical data of Xi’an City during the period from 1990 to 2010 and the software of Eview were used to fit the relationships between economic growth and the three environmental indicators (industrial waste gas, waste water and solid wastes) in Xi’an, validate whether the relationships were based on the environmental Kuznets curve (EKC), and analyze the factors affecting the environmental quality with the factor analysis method. The results are as follows: ① All of the relationships between the economic growth and the three environmental indicators fell short of the environmental Kuznets curve, the relationships between the economic growth and the emission of waste gas and drainage of waste water met the inverted N curve, and the relationship between the economic growth and the emission of solid wastes was based on U curve; ② The emission of waste gas and drainage of waste water were in a decrease trend, but the emission of solid wastes was still in an increase trend, and the highest point was not reached yet: ③ The change of environmental quality in Xi’an was mainly caused by economic factors. References | Related Articles | Metrics

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Land Use/Cover Change in Loess Tableland Areas —A Case Study in the Loess Tableland Areas in Xianyang, Shaanxi Province TIAN Yi-Chao, LIANG Ming-Zhong 2013, 30 (3):  563-569.  Abstract ( 1642 )   PDF (1697KB) ( 1041 )   Based on the remote sensing images in the years 1990 and 2000 and the data of digital elevation model,stream systems,railways,highways,precipitation and temperature,the integrated use of Binary Logistic Regression and CA-Markov model was developed to simulate the land use patterns in the loess tableland areas in Xianyang,Shaanxi Province,and the land use types there in the near future were predicted.The results are as follows: ① There was an expansion of construction land and woodland during the period from 2000 to 2010,but the area of arable land,grasslands,waters and unused land was reduced,in which the reduction trend of arable land and the expansion trend of construction land were similar; ② Investigating from the conversion direction of land use types,grassland was mainly changed into woodlands,and then into farmland,construction land and waters; construction land and woodland was mainly from arable land; the change of area of woodland and waters was not significant,unused land was mainly from arable land,and some unused land in small area was changed into arable land; ③ Through inputting the parameters which were combined with the results of Binary Logistic Regression,the application range of CA-Markov model was expanded,and the prediction of land use was improved to some degree; ④ It was predicted that the area of construction land in the study area in 2020 would be expanded dramatically,especially in the surrounding regions of the original construction land,along the railways and highways,and in Sanyuan County of Qindu District,Xianyang City. References | Related Articles | Metrics