Table of Content

15 July 2019, Volume 36 Issue 4 Previous Issue    Next Issue

Select

Cover 2019, 36 (4):  0-0.  Abstract ( 454 )   PDF (414KB) ( 85 )   References | Related Articles | Metrics

Select

Contents 2019, 36 (4):  0-0.  Abstract ( 141 )   PDF (309KB) ( 139 )   Related Articles | Metrics

Select

Hydrochemical Composition of Natural Waters and Its Affecting Factors in the East Hunshandak Sandy Land REN Xiao-zong, LI Jian-gang, LIU Min, LI Ji-yan 2019, 36 (4):  791-800.  Abstract ( 737 )   PDF (2076KB) ( 272 )   The East Hunshandak Sandy Land is located in the Inner Mongolia Plateau. Compared with other deserts in West China, water resources in Hunshandak Sandy Land are relatively abundant, even some rivers originate from the sandy land. In this study 24 water samples including 11 groundwater samples, 6 lake water samples, 5 river water samples and 2 spring water samples were collected from 2011 to 2012. Physical parameters including the pH value, oxidation-reduction potential, electrical conductivity, total dissolved solids and salinity were measured on site with a portable instrument. Major anions (Cl-, NO3- and SO42-) and cations (Na+, K+, Mg2+, Ca2+ and NH4+) were determined by electrochemical detectors of ion chromatography at the Institute of Geology and Geophysics, Chinese Academy of Sciences. The concentration of HCO3- was measured by titration with HCl following Gran Method. The results showed that total dissolved solids (TDS) of water samples ranged from 67 mg·L-1 to 660 mg·L-1, which revealed that freshwater was dominant in the natural waters in Hunshandak Sandy Land. Moreover, the concentration of calcium was the highest in cations in almost all water samples, while that of bicarbonate was the highest in anions except for some groundwater and spring water samples. The pH values of groundwater were commonly slightly lower than 7, while those of others, such as lake water, river water and spring water, were slightly higher than 7. In addition, almost all concentrations of cations and anions in groundwater were the highest in natural waters. The hydrochemical types were determined by the original Durov Diagram. The results showed that surface water was dominated by bicarbonate, but groundwater was dominated by bicarbonate, mixed type or sulfate. Gibbs Diagram was used to determine the factors affecting the hydrochemical composition of natural waters. Different from the deserts in the western and central parts of China, where the evaporation was so strong that evaporation-crystallization affected mainly the hydrochemical composition of the natural waters, and the water-rock interaction was the main factor affecting the natural waters in East Hunshandak Sandy Land. Ion ratios in samples indicated that the rock weathering in waters was different. The weathering degree of evaporative salt rock and silicate rock in groundwater is higher, while that of carbonate rock is lower, which may be caused by the insufficient supply of carbon dioxide due to the long water-rock interaction time in groundwater. On the contrary, due to the short water-rock interaction time and sufficient supply of carbon dioxide, the degree of weathering of evaporative and silicate rocks in surface water is low, while that of carbonate rocks is high. References | Related Articles | Metrics

Select

Variation of Soil Temperature in the Desert-Oasis Ecotone GOU Qian-qian, LI Qiao-qiao, QU Jian-jun, WANG Guo-hua 2019, 36 (4):  809-815.  Abstract ( 477 )   PDF (1565KB) ( 357 )   In this study, the data of soil temperature and meteorological factors at a station in an inland river basin in Linze from 2004 to 2014 were used to analyze the soil temperature variation and its main affecting factors in the desert-oasis ecotone in central Hexi Corridor. The results showed that both the daily and monthly changes of soil temperature were sine-curve-shaped, and the occurrence time of the highest and lowest temperature in each soil layer was gradually delayed with the increase of soil depth. The average annual soil temperature was generally decreased at first and then increased with the increase of soil depth. The correlation between air temperature and soil temperature was the most significant. Three distinct layers of soil temperature in this region were defined, i.e., the soil layers of 0-20 cm deep, around 40 cm deep and 60-100 cm deep. Finally, the empirical prediction equations between meteorological indexes and soil temperature of each soil layer were developed using the correlation analysis and the multiple stepwise linear regression. References | Related Articles | Metrics

Select

Age Structure of Malus sieversii Population in Ili of Xinjiang and Kazakhstan ZHANG Ping, Lü Zhao-zhi, ZHANG Xin, ZHAO Xiang-ping, ZHNAG Yong-guang, Gulzhanat Tanabekova, Maisupova Bagila, Adilbayeva Zhanera, CUI Zhi-jun 2019, 36 (4):  844-853.  Abstract ( 774 )   PDF (1405KB) ( 302 )   Environmental and human stress accelerate the loss of wild apple habitats in Central Asia, causing the decline of population and viability of wild apples. In this paper, the population of a tertiary relict plant Malus sieversii (Ledeb.) M. Roem (wild apple) was studied. The status of wild apple population was systematically surveyed, and the age structure, fruit yield and population dynamic change of wild apple in Xinjiang (Ili River Valley) of China and Kazakhstan were compared. The results showed that the population age structure was currently and even in the 1970s dominated by the middle-aged (15-50 cm) trees, and the proportion of young (0-15 cm) and old (50-75 cm) trees was low in the Ili River Valley of Xinjiang and Kazakhstan. Compared with the population in Xinjiang, the life vitality of wild apple population was weaker while the fruit yield was relatively high, and the population was in a severe decline (Deevey-Ⅲ) in Kazakhstan from 1969 to 1970. In 2013, the population of wild apple trees in Kazakhstan showed a strong life vitality and stable population structure (Deevey-Ⅱ). The key factor that resulted in the decline of wild apple population was the lack of young individual trees. Detailed advices were proposed to the conservation and regeneration of wild apple forest in Xinjiang and Kazakhstan. For Kazakhstan, an appropriate level of grazing was suggested to enhance the seed spreading and germinating. For Ili of Xinjiang, the conservation areas should be established, while the wild apple fruit collection and mowing in wild apple forest should be prohibited or under well control so as to protect the seedlings as well as the natural seed bank. References | Related Articles | Metrics

Select

Response of Plant Seedling Growth to the Changes in Precipitation and Wind Velocity in Horqin Sandy Land SUN Shan-shan, LIU Xin-ping, WEI Shui-lian, ZHANG Tong-hui, HE Yu-hui, Chelmeg, LYU Peng, WANG Ming-ming 2019, 36 (4):  870-877.  Abstract ( 682 )   PDF (1287KB) ( 285 )   To study the response of plant seedling growth to the change of precipitation and wind velocity in sandy land, we carried out simulation control experiments by artificial precipitation and wind screen reduction in 40 concrete square pools of 2 m×2 m×2 m during the period of seed germination starting in mid-April 2016. The results showed that: ① Wind velocity, precipitation and interaction of these two treatments had no significant effect on the species richness (P>0.05). The seed germination rates could be increased by 4.9% and 1.3% under the 20% wind velocity reduction and 60% precipitation increment, respectively, compared with those of controlled experiment. The species richness was increased by 7.2% under 20% reduction of wind velocity and 60% precipitation increment;②The seedling density and height fluctuated greatly under different precipitation treatments. A wind speed reduction can significantly promote seedling growth height in sandy land, especially for Salsola collina and Corispermum macrocarpum (P<0.01). Under the condition of natural wind speed, 30% precipitation increment obviously promoted the growth of seedling height, while 60% precipitation increment was contrary. Under the 20% wind velocity reduction, the growth height of Bassia dasyphylla seedlings could be greatly promoted by the 60% precipitation increment.The synergistic effects of the 40% wind velocity reduction and 30% and 60% precipitation increments resulted in a significant decrease in the growth height of the seedlings of Bassia dasyphylla, Salsola collina and Corispermum macrocarpum. ③ The effects of different wind velocity and precipitation treatments on species diversity, including the Simpson index (D), Shannon-Winner index (H) and Pielou evenness index (J), were not significant (P>0.05). In conclusion, the effect of 30% precipitation increment on the species richness during the period of seed germination was significant, wind velocity was the main factor affecting the height of plant seedlings. Under the natural conditions, the increase of seedling height was the maximum under 40% wind velocity reduction. The response of species diversity to the change of wind velocity and precipitation was not sensitive, which indicated that the community structure of the ecosystem was comparatively stable in the Horqin Sandy Land. References | Related Articles | Metrics

Select

Effects of Soil Water Stress on Photosynthetic Characteristics and Biomass of Medicago sativa LIU Jun, QI Guang-ping, KANG Yan-xia, MA Yan-lin, LI Zhi 2019, 36 (4):  893-900.  Abstract ( 434 )   PDF (1026KB) ( 263 )   Medicago sativa is an important legume forage in China, and it is strong in drought resistance. However, water deficit is still the main stress factor affecting its yield. The photosynthetic characteristics and yield of M. sativa under different water stress conditions were studied by carrying out the field experiments. The results showed that:  ① Soil water stress affected significantly the photoresponse parameters of M. sativa. With the increase of soil water stress, the maximum net photosynthetic rate, apparent quantum yield and light saturation point were decreased gradually, but the dark respiration rate and light compensation point were gradually increased, thus the dyssophotic absorption and conversion efficiency of M. sativa in its photosynthesis were directly affected;  ② With the increase of soil water stress, the net photosynthetic rate (Pn) and transpiration rate (Tr) of M. sativa leaves were reduced significantly, but the stomatal conductance (Gs) was decreased at first and then increased, which revealed that the stomatal factors under slight water stress were the main factors resulting in the Pn reduction, and the non-stomatal factors under moderate and severe water stress were the main factors resulting in the Pn reduction;  ③ When the photosynthetically active radiation (PAR) value was 1 200 μmol·m?2·s-1, the water use efficiency (WUE) of slight water stress was significantly higher than that of full irrigation (P<0.05), indicating that moderate water stress could improve the water use efficiency of M. sativa; ④ There was no significant difference of hay yield between slight water stress and fully irrigation, indicating that high forage yield and water-saving irrigation could be achieved under slight water stress. References | Related Articles | Metrics

Select

Drought Characteristics in Inner Mongolia Based on Precipitation Anomaly Percentage WU Ying-jie, LI Wei, WANG Wen-jun, QUAN Qiang, CHEN Xiao-jun, YIN Hang, ZHOU Quan-cheng, XU Kai-ran 2019, 36 (4):  943-952.  Abstract ( 867 )   PDF (2441KB) ( 305 )   The monthly precipitation data from 52 meteorological stations in Inner Mongolia from 1971 to 2015 were used. The methods of M-K test and precipitation anomaly percentage (Pa) were used to analyze the change trend and abrupt change of precipitation, and the spatiotemporal variation of drought at different time scales was also analyzed. The results showed that the inter-annual precipitation variation trend was basically maintained, and two abrupt changes took place in 1998 and 2012 in recent 45 years. Precipitation increased in spring, autumn and winter, but it was opposite in summer. Drought events occurred mainly in winter during the period from 1999 to 2011, and their frequency was the lowest in summer. Spatially, the annual precipitation decreased gradually from the east to the west. The change rate of precipitation was high in the area east of the Greater Khingan Mountains and west Bayan Nur, but it was low in Northwest Hulun Buir, central and southern parts of Tongliao, central part of Chifeng, and western Alxa. In addition, the probability of occurring drought at different levels was in an order of slight drought > extreme drought > moderate drought > severe drought. Drought events occurred generally in west Hulun Buir, Central-North Chifeng, North Tongliao, Central-West Xilin Gol League and West Alxa League. The Pa was in an increase trend in Central-East Hulun Buir, West Bayan Nur and East Alxa League, but it was in a decrease trend from South Hinggan League to Erdos and in Central-West Alxa. References | Related Articles | Metrics

Select

Variation of Aerosol and Its Effects on Precipitation in China Based on CMIP5 Models ZHAO Hong-fei, YANG Yi, DONG Jia-qi, LI Yu-zhen, LI Long-hui 2019, 36 (4):  953-962.  Abstract ( 671 )   PDF (1860KB) ( 332 )   Aerosol plays an important role in the physical and chemical processes in the atmosphere. As more and more aerosols are discharged into the atmosphere due to the enhancement of human activities, the climate problems caused by aerosol emissions have also attracted wide attention. The purposes of this study were to analyze the change of aerosol optical thickness (AOD) and its effects on precipitation by applying the linear trend analysis, correlation analysis and empirical orthogonal function (EOF). The spatiotemporal variation of aerosol and its effects on precipitation since the industrial revolution in China was also approached based on the multi-mode experimental data provided by the Phase Five of the Coupled Model Intercomparison Project (CMIP5). The result showed that the variation of AOD in China was in an increase trend from 1860 to 2000 (P<0.001), the increase trend was more significant in the area east of the “Hu’s Line” than that in the area west of it and after 1945. The increase rate after 1945 [0.380 7·(100a)-1] was significantly higher than that before 1945 [0.029 0·(100a)-1]. In the experiments in which the aerosol change was considered only, as the aerosol emissions were increased, precipitation was obviously decreased in 93.1% area of China (P<0.001). Precipitation was reduced predominantly in most of the southeast China, Sichuan Basin and southeast of Qinghai-Tibet Plateau, while the trend of precipitation reduction in northwest China was moderate. The decrease trend of precipitation was more significant after 1962 than that before it. The decrease rates were 118.04 mm·(100a)-1 in period after 1962 and 26.67 mm·(100a)-1 in period before 1962. The increase of aerosol emission served a role in the lessening of rainfall events’ frequency and precipitation intensity by inhibiting the light precipitation, and their reduction rates were 3.16 d·(100a)-1, 0.162 4 mm·d-1·(100a)-1, respectively. It provides an important scientific basis to study the climatic effects of AOD’s change on precipitation since the industrial revolution for better response to regional climate change in the future. References | Related Articles | Metrics

Select

Spatiotemporal Variation of Ozone Concentration and Its Affecting Factors over Inner Mongolia in Recent 3 Years CHEN Zhi-qing, SHAO Tian-jie, ZHAO Jing-bo 2019, 36 (4):  990-996.  Abstract ( 579 )   PDF (1811KB) ( 300 )   In order to study the O3 pollution over Inner Mongolia and its affecting factors, the data from the national environmental monitoring stations and national meteorological stations in 12 cities in Inner Mongolia from 2015 to 2017 were analyzed. The results showed that O3 pollution at different levels occurred in all the 12 cities. The overall O3 pollution in 2017 was aggravated compared with that in 2015, the O3 concentration was the highest and the O3 pollution was the most serious during the period from May to August, especially in July. Spatially, the O3 pollution was comparatively serious in the central and western parts of Inner Mongolia, which was synchronous with the economic development level. Particles, precursors and meteorological factors are the important factors affecting O3 concentration. There were the significantly negative correlations between the O3 concentration and the PM2.5, CO and NO2, and the O3 concentration decreased gradually with the increase of relative humidity. References | Related Articles | Metrics