Table of Content

15 July 2018, Volume 35 Issue 4 Previous Issue    Next Issue

Water and Soil Resources and Utilization

Select

Sensitivity of Runoff to LUCC and Climate Change in the Heihe River Basin LUO Kai-sheng, TAO Fu-lu 2018, 35 (4):  753-760.  doi: 10.13866/j.azr.2018.04.01 Abstract ( 1028 )   PDF (1108KB) ( 717 )   The purposes of this study was to quantitatively assess the sensitivity of runoff to climate change and land use/cover change (LUCC) in the Heihe River Basin during the period of 1980-2009. The study was based on the multiple data sources including the data of land use, digital elevation, soil, weather and runoff during the study period using the SWAT model. The results indicated that the sensitivity value of runoff to LUCC during the period of 1980-2009 was 0.020 mm·km-2. Moreover, the runoff changes caused by the variation of 1 mm precipitation in the upper, middle and lower streams were 0.49-0.288, 0.006-0.038 and 0-0.002 mm, and those caused by the variation of 1 ℃ temperature in the upper, middle and lower streams were 13.413-78.902, 1.105-6.500 and 0.461-2.710 mm, respectively. It was further found that the sensitivity of runoff to temperature was much higher than that to precipitation. The sensitivities of runoff to LUCC in the upper, middle and lower streams were 0.108, 0.004 and 0.001 mm·km-2 during the period from 1980 to 2009. Temporally, the sensitivity of runoff to LUCC in the whole drainage basin was holistically in a downward trend, and it was in a decrease trend in the upper stream but an increase trend in the lower reaches. The sensitivity of runoff to temperature in the drainage basin was in an increase trend during the period of 1980-2009. References | Related Articles | Metrics

Select

Effects of Water-retaining Agent and Microbial Agent on Soil Moisture and Nutrient Content SONG Shuang-shuang, SUN Bao-ping, ZHANG Jian-feng, WU Yi 2018, 35 (4):  761-769.  doi: 10.13866/j.azr.2018.04.02 Abstract ( 1149 )   PDF (1670KB) ( 821 )   As a high efficiency of water absorption material, polyacrylic acid potassium water-retaining agent and microbial agent can be mixed to significantly improve soil fertility. In this study, the polyacrylic acid potassium water-retaining agent was mixed with microbial agent to investigate their effects on soil moisture content, soil fertility and plant growth. Pot incubation tests were conducted to observe the growth of Pinus tabulaeformis and Medicago sativa. The contents of soil available N, P and K and soil moisture under these 2 plant species were tested and analyzed. Moreover, drought stress test was also carried out in the study. Results showed that the polyacrylic acid potassium water-retaining agent could be mixed with microbial agent to increase the contents of soil available N, P and K and soil moisture in varying degrees. Change trends of the contents of soil available nutrients under P. tabulaeformis and M. sativa were similar, but the optimal mix method was different for different plant species. For the annual P. tabulaeformis, the effect of high-concentration mix method on soil available N content was significant, and the effect of low-and moderate-concentration mix methods on the contents of soil available P and K was also high, and they were increased by 12%, 35% and 36% respectively. For M. sativa, the effect of high-concentration mix method on soil available N and P contents were significant, and the effect of low-and moderate-concentration mix method on soil available K was also high. The conditions of P. tabulaeformis and M. sativa growth and soil moisture level might be significantly improved when the moderate-concentration mix method was applied. For a defined area, it was needed to consider the actual conditions when using the water-retaining agent and microbial agent because of the different soil conditions, soil moisture level and nutrient level. References | Related Articles | Metrics

Select

Simulation of Daily Runoff Process in the Mainstream Area of the Tarim River Under Future Climate Scenario BAN Chun-guang, TAO Hui, DONG Yi-yang, ZHAO Cheng-yi 2018, 35 (4):  770-778.  doi: 10.13866/j.azr.2018.04.03 Abstract ( 5 )   PDF (2110KB) ( 0 )   In this study, the hydrological model of distributed MIKE SHE was used to calibrate and validate the change of monthly and annual runoff volumes at the hydrometric stations in the mainstream area of the Tarim River. The study was based on the air temperature and precipitation data observed by the meteorological stations named as Aral, Baicheng, Kuqa, Luntai, Korla and Tikanlik during the period of 1998-2007, and also the discharge data measured by three hydrometric stations including Xinquman, Yengbazar, and Qara during the period of 1998-2007. The climate model of HadGEM 2-ES was used to estimate the evolvement of runoff volume of mainstream of the Tarim River in the future (from 2021 to 2050) under climate scenarios. The results indicated that: ① The model of MIKE SHE was adopted to simulate the runoff process of mainstream of the Tarim River, and the model efficiency coefficients were all higher than 0.63, which showed that the applicability of this model was high; ② In the next 30 years, the monthly average temperature in the mainstream area of the Tarim River would be increased by 1.7-2.2 ℃ compared with that during the reference period (from 1981 to 2004), and the temperature increase in summer and autumn would be significant. Precipitation would be in an increase trend, its increase would be significant in spring but not in autumn; ③ Under the future climate scenarios, annual runoff volumes at the hydrometric stations would be in a decrease trend, especially in summer and autumn (P<0.01). In which the decrease of runoff volume at Qara Hydrometric Station in the lower reaches would be the most significantly (5.04%), but that at Xinquman Hydrometric Station in the upper reaches was the lowest (0.6%). In emission scenarios under various climatic conditions, the reduction of runoff volume was the least under RCP 2.6 (low emission) but the most under RCP 8.5 (high emission). The annual runoff volume of mainstream of the Tarim River under the future climate scenarios would be in a decrease trend, it would be more difficult to redistribute water resources, the ecological security would be threatened, and the human-land contradiction would become more serious. References | Related Articles | Metrics

Select

Effects of Subsurface Impermeable Film on Cotton Yield and Water Use Efficiency in Drip-irrigated Cotton Field HU Zhi-qiang, HOU Zhen-an, MIN Wei, YE Jun, WU Yan 2018, 35 (4):  779-788.  doi: 10.13866/j.azr.2018.04.04 Abstract ( 5 )   PDF (2130KB) ( 0 )   Over irrigation leads to deep percolation,which is one of the main pathways of water loss from drip irrigation field.Subsurface water retention technology (SWRT) can be used to effectively reduce the deep percolation and improve the water use efficiency.The objectives of this study were to determine the effects of irrigation volume and SWRT on soil moisture balance,cotton yield and water use efficiency in a drip-irrigated cotton field.The experimental was designed as 3×3 factorial with three irrigation volumes (340,440,and 540 mm) and three SWRT treatments (contrast,40 cm deep membrane and 60 cm deep membrane).Results showed that the soil moisture content (0-60 cm) and net soil water storage were significantly increased under the treatments of 40 cm and 60 cm deep membranes compared with that of contrast.Deep water percolation loss in soil layer deeper than 1 m was significantly increased with the increase of irrigation volume.Under 340 mm irrigation,there was no significant difference in deep water percolation loss among three SWRT treatments.Under 440 mm and 540 mm irrigation,the deep water percolation losses in the plots with 40 cm and 60 cm deep membranes were reduced by 64% and 72%,and 38% and 76%,respectively compared with those of contrast.Both the treatments of 40 cm and 60 cm deep membranes reduced significantly the evapotranspiration in the 340 mm irrigated plots.However,in the 540 mm irrigated plots,the 60 cm deep membrane treatment increased significantly the evapotranspiration compared with the contrast.In the 340 mm and 440 mm irrigated plots,the dry matter weight,yield,water use efficiency and economic benefits of cotton were significantly higher in the 40 cm and 60 cm deep membrane treatments than those in the contrast.But there were no significant differences between the 40 cm deep and 60 cm deep membrane treatments.In the 540 mm irrigated plots,the treatment of 60 cm deep membrane increased significantly the cotton dry matter weight and yield,water use efficiency and economic benefits.There was no significant difference between the 40 cm deep membrane and the contrast.Therefore,both the 40 cm and 60 cm deep membranes were suitable under low and moderate irrigation volumes (340 mm and 440 mm),and the SWRT of 60 cm deep membrane was preferable under high irrigation volume (540 mm). References | Related Articles | Metrics

Select

Soil Ecological Stoichiometry under the Planted of Pinus sylvestris var. mongolica Forests with Different Stand Ages in the Horqin Sandy Land SHU Min, JIANG Tao, WANG Dong-li, LIAN Zhao, TANG Jia-xi, KONG Tao, XU Yi-yuan, HAN Xiao-mei 2018, 35 (4):  789-795.  doi: 10.13866/j.azr.2018.04.05 Abstract ( 5 )   PDF (2672KB) ( 0 )   The observations of this study were to measure the contents of soil organic carbon (C), total nitrogen (N) and total phosphorus (P) in soil layer from 10 cm to 100 cm in depth under the planted Pinus sylvestris var. mongolica forests with different stand ages (for 15, 25, 35 and 45 years) over the Horqin Sandy Land. Moreover, the vertical distribution of ecological stoichiometric ratios of soil organic C, total N and total P under the planted forests with different stand ages was investigated so as to provide a theoretical basis for sustainable management of the planted forests. The results showed that the contents of soil organic C, total N and total P varied in ranges of 2.51-8.27, 0.12-0.45 and 0.14-0.21 g·kg-1 respectively, and all of them were below the national average level in China. As the increase of stand age of the forests, the contents of soil organic C, C/N and C/P were increased; the total N and total P were increased at first and then decreased, a significant decrease occurred under the forest with a 45 year stand age, and there was no significant change in N/P. As the increase of soil depth, both the soil organic C and total N were decreased, their contents were lower than one third of the total. While the C/N was increased but the C/P was decreased. The study results revealed that the soil C, N and P storages were increased although the contents of these soil nutrients were extremely poor in the Horqin Sandy Land. References | Related Articles | Metrics

Select

Soil Carbon Emission of Five Desert Shrubberies in the West Ordos Plateau WANG Shan, DANG Xiao-hong, GAO Yong, HU Sheng-rong, WANG Ze-yu, PAN Xia 2018, 35 (4):  796-803.  doi: 10.13866/j.azr.2018.04.06 Abstract ( 4 )   PDF (1489KB) ( 0 )   An Automated Soil CO2 Exchange Station was applied to study the soil CO2 emission and the main environmental factors of five desert shrubberies so as to get a more exact estimation of soil carbon emission and a clearer understanding of its affecting factors in the west Ordos Plateau. The results showed that the curve of daily variation of soil carbon emission rate was unimodal, and the maximum rate occurred during the period from 11:30 to 13:30 o’clock. The monthly soil carbon emission rate of the five desert shrubberies in growing season (from May to July) was much higher than that in non-growing season (October), and that of Helianthemum songaricum shrubbery was the highest and 0.76-1.67 times higher than that of other shrubberies. The annual average soil carbon emission rates under the shrubberies of Ammopiptanthus mongolicus, Zygophyllum xanthoxylum, Tetraena mongolica, H. songaricum and Reaumuria songarica were 8 090.63, 7 287.40, 7 868.16, 8 375.69 and 7 618.47 kg·hm-2·a-1 respectively. In the three future climate scenarios (low emission scenario B1, moderate emission scenario A1B and high emission scenario A2), the average soil carbon emission of five desert shrubberies would be increased by 8.30% compared with that in the baseline scenario, especially in the Z. xanthoxylum shrubbery. The response of soil carbon emission of different shrubberies to temperature change was different, but the difference was not significant. The research results could be referred in estimating carbon balance in arid and semiarid regions in the northwest China under global environmental change. References | Related Articles | Metrics

Select

Particle Size Distribution of Soil in Abandoned Farmland in Semiarid Area Based on Multifractal WANG Yan, String Bilge, JIA Xu, MENG Zhong-ju, LV Shi-jie 2018, 35 (4):  804-812.  doi: 10.13866/j.azr.2018.04.07 Abstract ( 5 )   PDF (2493KB) ( 0 )   In this study, the 5 types of abandoned farmland in the middle reaches of the Yinshan Mountain were lucubrated so as to investigate the characteristics of spatial variation and nonuniform soil particle size during the process of abandoned farmland succession. These types included the farmland abandoned in the same year and for 1, 2, 3 and 4 years respectively, and the distribution of soil particle size and of soil organic matter content at soil layer of 0-80 cm in depth was analyzed. Base on the multifractal theory analysis, the distribution of soil particles was determined, and its relationship with the variation of soil organic matter content was explored. The results showed that the sand content was positively correlated to multifractal parameters D0, D1 and α0, but it was negatively correlated to the organic matter content. The distribution of soil particle size was mainly affected by sand content in the study area. With the increase of sand content in soil, the distribution range of soil particle size became wider and more discrete, and the soil progressed in a coarse-grained succession. With the increase of farmland-abandoned years, both the cosmid content and organic matter content in topsoil were in a decrease trend, and there was an extremely significant positive correlation between them, so the change trend of cosmid content could be used to predict the change trend of organic matter content in topsoil. References | Related Articles | Metrics

Select

Loess Moisture Migration in Heifangtai of Gansu Province SHI Lan-jun, QIAO Xiao-ying, ZENG Lei, ZHAO Gui-zhang 2018, 35 (4):  813-820.  doi: 10.13866/j.azr.2018.04.08 Abstract ( 7 )   PDF (2842KB) ( 0 )   In this study,a numerical simulation of vadose water migration in Heifangtai of Gansu Province was carried out based on the analyzed results of the saturated-unsaturated loess moisture migration by using the Hydrus-1D software.The study was based on the field experiments and the saturated-unsaturated soil moisture migration theory.The simulation was verified using the field experiments,the fitted parameters of two kinds of soil were applied,and the simulated and measured values of soil moisture content were compared and analyzed.The results showed that; ① The soil moisture content changed in a fluctuation way; ② Soil water infiltration rate and the phreatic water evaporation rate were decreased with an increase of phreatic water depth; water infiltration rates of the two kinds of soil tended to be similar when the phreatic water depth was deeper than 300 cm,and the phreatic water evaporation rate of silty loam was lower than that of homogeneous loess.In conclusion,the spatiotemporal variation of soil moisture content was significant.The study results could be referred in researching the water distribution and change of landslide. References | Related Articles | Metrics

Climate andClimatic Resources

Select

Spatial Difference of Microclimate in Shelterbelts in Newly Reclaimed Land in Jiya Township in Hotan, Xinjiang MAO Dong-lei, CAI Fu-yan, ZHAO Feng, LEI Jia-qiang, LAI Feng-bing, XUE Jie 2018, 35 (4):  821-829.  doi: 10.13866/j.azr.2018.04.09 Abstract ( 10 )   PDF (2118KB) ( 0 )   The purposes of this study were to analyze the spatiotemporal differences of daily wind velocity,air temperature,relative humidity,solar radiation and photosynthetically active radiation in four site types in and out of the shelterbelts in newly reclaimed land in Jiya Township from 13 July to 3 August,2011.Moreover,the differences of daily meteorological factors in four landscape types on a fine day and during a sand-blowing weather were compared.Based on the field observation,the correlation statistical method was used to analyze the spatial differences of microclimatic factors.The results showed that the daily wind velocities at the height of 1 m in the shelterbelts of Populus alba,Calligonum mongolicum and Tamarix ramosissima were reduced by 76.43%,95.85% and 78.74% respectively than that over a sand-shifting land.The wind velocities at the height of 0.5 m were reduced by 78.07%,97.80% and 93.82% respectively than that over sand-shifting land.The vegetation coverages of shelterbelts of P.alba,C.mongolicum and T.ramosissima were 12%,80% and 40% respectively,which revealed that the effects of wind prevention would be better with the increase of vegetation coverage.The wind speed was lower near ground surface.The daily air temperatures in the shelterbelts of P.alba,C.mongolicum and T.ramosissima were decreased by 0.93 ℃,1.31 ℃ and 0.82 ℃ respectively than that over sand-shifting land,and the daily relative humidities were increased by 18.96%,23.34% and 14.78% respectively compared with that over sand-shifting land,which showed that the air temperature could be decreased but the air humidity increased by plants.The change trends of photosynthetically active radiation (PAR) and solar radiation were roughly the same,the maximum value of daily solar radiation occurred over sand-shifting land,and that of daily PAR in C.mongolicum shelterbelt,and both the lowest daily values in the P.alba shelterbelt.The change trends of air temperature on a fine day and during a sand-blowing weather were roughly the same.The variation of relative humidity was significant in the forenoon on fine day,and the relative humidity decreased gradually from sunrise during a sand-blowing weather.In summer,the spatial difference of microclimate in newly reclaimed land was affected by tree species,plant height,vegetation coverage,porosity and distances from shelterbelts. References | Related Articles | Metrics

Select

Surface Energy Balance Closure of Summer, Autumn and Winter in the Northern Margin of Taklimakan Desert CAO Huan-qi, HE Qing, JIN Li-li, LI Zhen-jie, YANG Xing-hua, HUO Wen 2018, 35 (4):  830-839.  doi: 10.13866/j.azr.2018.04.10 Abstract ( 765 )   PDF (2309KB) ( 681 )   Energy balance in the terrestrial ecosystem plays an important role in regional climate and water balance. In this study, the characteristics of surface energy balance were researched using the ordinary least square (OLS) method and energy balance ratio (EBR) method based on the surface flux data observed at Xiaotang land-atmospheric interation observation station in the northern marginal zone of the Taklimakan Desert during the period from July to December 2014. The results showed that, except for the latent heat flux, the daily variation curves of other energy flux components were inverted “U-shaped” and unimodal, which were characterized by seasonal variation and in an order of summer>autumn>winter. The energy balance was in an order of whole day>daytime>night and in a degressive trend. The energy closure degree of 5 cm deep soil heat flux was significantly higher than that of topsoil heat flux. The energy closure ratio fluctuated sharply at the sunrise and sunset, it was negative at night, and apparently higher in the afternoon than in the morning. Under the different weather conditions, the energy closure ratio was in an order of sunshine day>cloudy day>sandstorm day>rainfall day. References | Related Articles | Metrics

Select

Establishment and Spatial Distribution of Snowline in Xinjiang ZHANG Lian-cheng, HU Lie-qun, LI Shuai, HOU Xiao-gang, ZHENG Zhao-jun 2018, 35 (4):  840-845.  doi: 10.13866/j.azr.2018.04.11 Abstract ( 8 )   PDF (1215KB) ( 0 )   In this paper study, the daily snow product MOD10A1/MYD10A1 data in 2015 and the snow cover duration ratio method were used to extract the snowlines in Xinjiang, and the Kriging interpolation was used to establish the snowline fields in the study area. On which the spatial distribution of snowlines was studied. The results revealed that the mean absolute error (MAE) of snowline field established by the ordinary Kriging interpolation in Xinjiang was 4.49 m, the root mean square error (RMSE) was 48.93 m, and the errors could satisfy the accuracy requirements of this study. The analyzed results of the whole study area revealed that the snowline elevation was low in the north and east but high in the south and west, it varied in a range of 3 000-5 600 m a. s. l., its longitude and latitude zonal distribution patterns were typical, and the snowline fields were dense in the south but sparse in the north. Locally, the snowline elevation was high in the southern and eastern parts but low in the northern and western parts of the Tianshan Mountains; it was high in the central part but low on both sides of the Kunlun Mountain; and it decreased gradually from the northwest to the southeast of the Altay Mountain. The regional snowline distribution was quite different, the internal snowline distribution was complex, and the difference of snowline elevation was significant. References | Related Articles | Metrics

Select

Spatiotemporal Distribution of Cloud Liquid Water Volume over Three Main Mountains in Xinjiang ZHANG Xiao-juan, WANG Jun, HUANG Guan, CHEN Yong-hang, YANG Lian-mei, LI Hong-jun, LI Man, ZHENG Ning 2018, 35 (4):  846-854.  doi: 10.13866/j.azr.2018.04.12 Abstract ( 850 )   PDF (6395KB) ( 552 )   A case study on the spatiotemporal distribution of cloud liquid water over Xinjiang, especially over its three main mountainous with abundant cloud liquid water, was carried out using the cloud data set distributed by NASA (AIRS/Aqua L2 Standard Physical Retrieval (AIRS + AMSU) V006 (AIRX2RET)). The results showed that the cloud liquid water volume over north Xinjiang was higher than that over south Xinjiang, it was higher over the mountains than that over the desert basins, it over the windward slope of the mountains was as high as 500×10-6 kg·m-2, and it decreased from the west to the east. Affected by the general atmospheric circulation, the cloud liquid water over the whole study area, Tianshan Mountains and Altay Mountains was abundant in spring, and its volumes over these regions were all higher than 350×10-6 kg·m-2. The cloud water over the Kunlun Mountains was abundant in summer, but it was low over the whole study area in autumn and less than 20×10-6 kg·m-2. The average annual cloud water volume fluctuated between 42.47×10-6 kg·m-2 and 455.32×10-6 kg·m-2 in recent 13 years. The cloud liquid water was generally stable in the whole study area, but is was in a decrease trend in the three main mountainous. The cloud liquid water volume was in an upward trend in the study area from 2009 to 2010, especially in the Tianshan Mountains. The curves of annual cloud water volumes over the three main mountains were unimodal, and the highest values of cloud liquid water over the Altay, Tianshan and Kunlun mountains occurred from February to April, March to May and April to August, and the peak values were 822.30×10-6, 869.75×10-6 and 742.82×10-6 kg·m-2, respectively. References | Related Articles | Metrics

Select

Spatiotemporal Distribution of Temperature in the Tianshan Mountains Based on DEM LI Li, ZHANG Zheng-yong, LIU Lin, FAN Man-man 2018, 35 (4):  855-863.  doi: 10.13866/j.azr.2018.04.13 Abstract ( 4 )   PDF (2550KB) ( 0 )   Temperature in mountainous areas is mainly determined and decided by the solar radiation, and the distribution on the surface of the earth is closely and inescapably related to the regional topographic conditions, especially in mountainous areas. The GIS analysis technology and DEM as well as the data of temperature observation, slope of the terrain, slope aspect, terrain shading areas and other factors were used and utilized in this study on the basis of the traditional temperature statistical model. The purposes of this study were to carry out small-scale simulation and correction of air temperature in mountainous area, and to build a distributed mountainous terrain correction model. The results indicated that the values simulated by the modified model were better than those by the conventional temperature statistical model. The temperature distribution patterns and trends in the Tianshan mountainous areas were consistent with those obtained by other methods. The difference of temperature and space distribution was the lowest in winter but the highest in summer. The lapse rate of seasonal temperature variation was in an order of summer>spring>autumn>winter, and there was an obvious temperature inversion in a vertical zone of 1 000-2 000 m a.s.l. in winter. The change rate of the temperature with slop was the highest in a slope range of 0°-15°. The modified model is feasible and viable method for high-precision calculation of spatial distribution of air temperature in any regional unit in mountainous area, and could be referred a certain reference value for researching the air temperature simulation and ecological hydrological processes in mountainous areas. References | Related Articles | Metrics

Select

Spatiotemporal Variation of Accumulated Value of Temperature ≥10 ℃ in Tacheng During the Period of 1961－2016 KANG Li-juan, Batur Bake, FENG Li-ye, GE Yi-cheng, Sajidan Abudukerimu 2018, 35 (4):  864-871.  doi: 10.13866/j.azr.2018.04.14 Abstract ( 13 )   PDF (1597KB) ( 0 )   In this paper, the spatiotemporal variation of the accumulated value of temperature ≥10 ℃ in Tacheng was analyzed using the methods of linear climate tendency, cumulative anomalies, Mann-kendall mutation test and ArcGIS space interpolation based on the daily average temperature data from 6 meteorological stations in Tacheng during the period from 1961 to 2016. The results showed that the first date, last date, duration and accumulated value of temperature ≥10 ℃ in the study area were changed by -0.12 d·(10a)-1, 0.15 d·(10a)-1, 0.27 d·(10a)-1 and 75.39 ℃·(10a)-1 respectively. Moreover, the mutations of the last date, duration and accumulated value of temperature ≥10 ℃ occurred. The accumulated value of temperature ≥10 ℃ in the study area varied in a range from 2 450 ℃ to 3 950 ℃, and it was higher in the south than that in the north. Compared with the period Ⅱ (1995-2016) and period Ⅰ (1961-1994), the accumulated value of temperature ≥10 ℃ increased to some extent, the proportion of the area with accumulated value (2 450-3 150 ℃) of temperature ≥10 ℃ was reduced obviously, but the proportions of the areas with accumulated values of 3 150-3 450 ℃, 3 950-4 150 ℃ and 4 150-4 250 ℃ were increased. References | Related Articles | Metrics

Select

Application of CWT Method in Identifying Water Vapor Sources of Summer Precipitation in China MENG Hong-fei, ZHANG Ming-jun, WANG Sheng-jie, QIU Xue, DU Ming-xia, MA Rong 2018, 35 (4):  872-881.  doi: 10.13866/j.azr.2018.04.15 Abstract ( 17 )   PDF (5556KB) ( 7 )   The water vapor sources of summer precipitation over west China (Urumqi, Qilian and Madoi) and east China (Changsha and Guangzhou) were analyzed by the backward trajectory calculation module and concentration weighted trajectory (CWT) of TrajStat software and combined with water vapor flux. The results showed that: ① Summer precipitation in Urumqi, Qilian and Madoi was significantly affected by the westerly water vapor, that in Changsha by the Western Pacific water vapor, and that in Guangzhou by the Indian Ocean water vapor; ② Locally recycled water vapor participated in summer precipitation over 5 sampling sites. The recycled water vapor affecting summer precipitation in west China was mainly distributed in the mountainous areas and basins where the relative humidity was high and the areas where the evaporation capacity was high. In east China, however, the recycled water vapor affecting summer precipitation was mainly distributed in the places where the surface waters are concentrative; ③ Over west China, the change of d value of water vapor in airmass was affected by both evaporation and underlying surface in the process of water vapor movement. Over east China, however, it was generally affected by evaporation only. References | Related Articles | Metrics

Plant and Plant Physiology

Select

Significance of Photoinhibition Response Mechanism of Sabina vulgaris Ant.in the Mu Us Sandland ZHANG Jin-ling, CHEN Hai-peng, CHENG Da, LI Yu-ling 2018, 35 (4):  882-890.  doi: 10.13866/j.azr.2018.04.16 Abstract ( 718 )   PDF (1074KB) ( 426 )   Photoinhibition is common in plants which grow under natural conditions.For the duration of species,plants have developed a variety of photoinhibition defense mechanisms during their long-term adaptation and evolution,such as the exercise to avoid light by leaves and chloroplasts,photorespiration,active oxygen scavenging system,conversion of light harvesting pigment,protection by phenolic compounds (anthocyanin,for example),increasing non-photochemical dissipation,depending on the xanthophyll cycle thermal dissipation,and accelerating the turnover of D1 protein.Sabina vulgaris Ant.is the only natural evergreen coniferous shrub in the Mu Us Sandland,it has a strong vitality,a wide range of adaptability,good ecological function and high medical value.The photoinhibition defense mechanisms,such as the heat dissipation mechanism,play an important role during the natural regeneration of S.vulgaris in the desert with strong light environment.In this paper,the photoinhibition of plants and the main photoinhibition defense mechanisms in plants under strong light were reviewed.Light energy is the power source and the basic driving force of photosynthesis,energy shortage restricts photosynthesis,and photoinhibition of photosynthesis caused by light energy exceeds the photosynthesis need.Under strong light stress,photosynthetic pigment antenna absorbing the excessive solar light causes photoinhibition,and then affects the photosynthetic metabolism.Although the light is the direct reason of plant photoinhibition,drought and low or high temperature stress caused by saline and seasonal change lead indirectly to plant photoinhibition.There are two situations for photoinhibition: One is that plant can recover after suffering from photoinhibition,strong light provides more photochemical effect than the leaf photosynthesis,and photosynthesis process overload could cause lower photonutilization and lower photosynthetic quantum yield,this situation occurs often in the sun plants,which depends on the energy dissipation mechanism occurring mainly in photosystem Ⅱ (PSⅡ) reversible inactivation and relating to the light harvesting complex LHCⅡ (Light-harvesting complex Ⅱ) reversible detachment.The other is that plant cannot recover after suffering from photoinhibition called photodamage,extremely high radiation damages the photosynthetic pigment and thylakoid structure,this case occurs often in ombrophytes,which causes a photosynthetic organ damage dominated by the PSⅡ’s irreversible damage.The present research and prospect of the photoinhibition defense mechanisms of S.vulgaris were briefly summarized.In recent years,although there are many research reports about S.vulgaris, the research on photoinhibition defense mechanism of S.vulgaris is less.In general,the research about photoinhibition defense mechanisms of Sabina vulgaris still remains at the preliminary exploration stage,and how S.vulgaris defenses the photoinhibition by photosynthetic physiological and molecular mechanisms is not clear. References | Related Articles | Metrics

Select

Microstructures of Leaves of 10 Brachytheciaceae Plant Species from the Region of Glacier No.1 in the Tianshan Mountains WANG Jian-hong, CHEN Qiu-yan, WANG Hong, YUAN Zhen-yan, WU Yu-huan 2018, 35 (4):  891-898.  doi: 10.13866/j.azr.2018.04.17 Abstract ( 12 )   PDF (1580KB) ( 0 )   It is always difficult to classify the Brachytheciaceae plant species. In this study, the microstructures of leaves of 10 Brachytheciaceae plant species from the region of glacier No.1 in the Tianshan Mountains, Xinjiang were studied by light microscope and SEM. The results indicated that the leaf apexes of these 10 species are acuminate or long-hair-shaped. The leaf apex cells are transparent, short or narrow. The leaf cell walls are thick, and the water conducting cells are larger. When the leaves of the plant are dry, the cell wall has different degree of conversity, and also some tiny holes on the surface of the most specie. The microstructures of Brachythecium B.S.G., Cirriphyllum Grout. and Rhynchostegium B.S.G. are different. The morphological features of leaves of the plant species in different genera and even in the same genera are different due to the different growing environment, which revealed that the microstructures of these 10 species are closely related to the growing environment. The results of this study could provide some information for the classification of Brachytheciaceae plant species in the region of Glacier No.1 in the Tianshan Mountains. References | Related Articles | Metrics

Select

Sensitivity of Radial Growth of Populus euphratica to Temperature in the Upper Reaches of the Tarim River GOU Xiao-xia, YE Mao, WANG Liang-liang, GOU Xiao-hong 2018, 35 (4):  899-904.  doi: 10.13866/j.azr.2018.04.18 Abstract ( 7 )   PDF (1414KB) ( 0 )   Based on the meteorological data and the tree-ring data of Populus euphratica from the upper reaches of the Tarim River,the radial growth of P.euphratica and its correlations with climatic factors were analyzed.The sensitivity of radial growth of P.euphratica to temperature was investigated.The results showed that: ① In the past 170 years,the curve of tree-ring growth of P.euphratica was bimodal with a low value,and the two peaks occurred in 1857 and 1879 respectively.After 1879,the tree-ring growth was in a significant downward trend,and the lowest value occurred in 1955.After that,the tree-ring growth began to increase but decrease slightly after 1989; ② The tree-ring index was negatively correlated with the average temperature from June to September,which indicated that temperature was the main factor affecting the radial growth of P.euphratica in upper reaches of the Tarim River.The radial growth of P.euphratica was in a decrease trend with the increase of temperature; ③ The sensitivity of radial growth of P.euphratica to temperature change was different.The sensitivity of radial growth of P.euphratica to temperature was high at first and then low,and the most sensitive temperature of radial growth of P.euphratica was 18.6 ℃.So it was considered that 18.6 ℃ was the most optimal temperature for the growth of P.euphratica. References | Related Articles | Metrics

Select

Estimation of Annual Biomass of Individual Populus euphratica Based on Tree-ring Data HUANG Yun-mei, XU Hai-liang, ZHANG Gaung-peng, ZHAO Xin-feng 2018, 35 (4):  905-911.  doi: 10.13866/j.azr.2018.04.19 Abstract ( 12 )   PDF (1525KB) ( 0 )   In the downstream of the Tarim River,Populus euphratica is the key species in desert forests which play a crucial role of protecting the local ecological environment and alleviating wind-blown sand disasters.Biomass of P.euphratica is an important index in studying the functions and services of desert riparian forest ecosystem.P.euphratica, the only tree species in the desert in China,is a national second-class protected plant species with high value for its rareness.Therefore,the common destructive ways cannot be used to study the tree biomass,and it is difficult to precisely measure the biomass.In this research,an innovatively destructive way was used to collect the samples so as to calculate the values of annual stem biomass.For an individual tree,the experiment samples were taken from different heights of its stem to attain the corresponding tree-ring width.The results are as follows: ① There were the significant correlations between the tree-ring growth at different heights,and the average Pearson correlation coefficient was 0.878.The trunk densities at heights of 0-0.5,0.5-1,1-1.5,1.5-2 and 2-2.5 m were 500.2,475.6,502.2,477.2 and 420.194 kg·m-3 respectively,and the standard deviation was 32.7; ② Based on the information of tree-ring and trunk densities at different heights,the values of annual biomass of P.euphratica can be calculated accurately.In the experiment,the annual biomass of trunk at 0.5-1.5 m height varied in a range of 0.61-1.54 kg during the period of 1997-2013,and the average annual biomass was 0.92 kg.During the period from 2002 to 2003,the annual biomass increased obviously,and the average annual biomass was 1.54 kg.The sampling way in this research was less destructive and easy to operate,and could be effectively applied in practical use for calculating the annual aboveground biomass of individual P.euphratica trees.The estimation of annual stem biomass is of great significance for studying the change of ecological value of desert riparian forest. References | Related Articles | Metrics

Select

Relationship Between Soil Factors and Ephemeral Plant Species Diversity on Typical Sand Dunes in the Mosuowan Region LI Ya-ping, JIANG Jin, SONG Chun-wu, LI Zhe-hua 2018, 35 (4):  912-919.  doi: 10.13866/j.azr.2018.04.20 Abstract ( 12 )   PDF (1016KB) ( 0 )   In this study, the fixed dunes with vegetation coverage of 10%, 15% and 30% in the Mosuowan region in southern marginal zone of the Gurbantunggut Desert were selected as the typical sample plots to analyze the quadrats, environmental factors and species abundance using the canonical correlation and the means of canonical correlation analysis. Moreover, the relationships among the species diversity and the terrain factors as well as the soil physicochemical factors were analyzed. The results showed that there was a significant correlation between the species and the environmental factors, the first 4 axes could be used to explain 84.4% of total species variation, and soil sand was a sensitive indicator of species distribution. Species were distributed in a large number along the axes. Terrain affected significantly the species of Arnebia decumbens, Amberboa turanica, Echinops gmelinii and Salsola ruthenica; the species that were affected significantly by soil organic matter content, soil moisture content and soil pH value were Schismus arabicus, Ceratocarpus arenarius, Astragalus membranaceus and Erodium oxyrrhynchum. Results of the typical correlation analysis of different indicator groups revealed that the first pair of canonical correlation coefficient between the terrain and the species diversity was 0.54, the first pairs of canonical coefficients of soil physicochemical factors and species diversity were 0.93 and 0.96, the second pairs of canonical coefficients were 0.79 and 0.80, respectively, and there was a significant correlation. Among the topographical factors, the slope index affected mainly the species richness index Simpson; among the soil physicochemical factors, sand and soil organic matter content affected mainly the dominance index Shannon, and soil moisture content and pH value affected mainly the evenness index Pielou. The distribution of species in the study area was jointly affected by both terrain and soil factors. References | Related Articles | Metrics

Select

Effects of Supplementary Irrigation on Root System and Water Consumption of Winter Wheat in Semiarid Region YANG Wen-jia, WANG Shi-wen, LI Yu-lin, SUN Hai-ni, YIN Xiu-shuai, YIN Li-na, KE Qinq-bo, DENG Xi-ping 2018, 35 (4):  920-928.  doi: 10.13866/j.azr.2018.04.21 Abstract ( 11 )   PDF (1365KB) ( 0 )   Supplementary irrigation is an important approach for increasing crop yield in dryland agriculture.However,its effects on the crop yield,crop water use efficiency and soil water consumption are different in previous researches.In this study,the effects of supplementary irrigation on the yield,population,water use efficiency and root distribution of winter wheat and the soil moisture content were investigated.The field experiments were conducted in continues two years at Changwu Research Station in the Loess Plateau,China.The experiments included four different irrigation treatments: no irrigation (W0),30 mm irrigation at jointing stage (W1),30 mm irrigation at booting stage (W2),and 30 mm irrigation at jointing stage +30 mm irrigation at booting stage (W3).The results showed that the hsupplementary irrigation could be used to increase wheat yield,but not water use efficiency.The wheat yield could be increased more under the irrigation treatments of W1 and W3 than that under the W0 and W2.The proportions of water consumption during the jointing and flowering stages were 42% and 29% of the total water consumption during the whole growth period of winter wheat in the continue two years,and the supplemental irrigation increased the proportion of water consumption during the jointing-flowering stage in normal flow year,reduced the tillering polarization,and increased the population of winter wheat during its flowering stage.Supplementary irrigation affected significantly the root distribution by increasing shallow roots and decreasing deep roots.Compared with W0,the root densities at 1-2 m depth under the irrigation treatments of W1,W2 and W3 were decreased by 12%,7% and 16% in normal flow year,and by 31%,16% and 39% in high flow years.As a results,the supplementary irrigation failed to make the full use of deep soil water storage.In addition,the effect of supplementary irrigation on yield and water use efficiency of winter wheat was also significantly affected by rainfall during the growth period.To make the full use of deep soil water storage by deep roots is key approach in increasing crop yield and water use efficiency in dryland agriculture.The results of this study showed that the supplemental irrigation did not regulate the deep roots and deep water consumption,which brought about a yield increased without increasing water use efficiency.The result suggested that supplementary irrigation should be applied in the areas with less rainfall for increasing the crop water use efficiency,and how to regulate the deep root distribution with supplementary irrigation should be considered in the future research. References | Related Articles | Metrics

Select

An Overview of Stomatal and Non-stomatal Limitations to Photosynthesis of Plants GAO Guan-long, FENG Qi, ZHANG Xiao-you, SI Jian-hua, YU Teng-fei 2018, 35 (4):  929-937.  doi: 10.13866/j.azr.2018.04.22 Abstract ( 4881 )   PDF (952KB) ( 1918 )   External stresses affect the plant growth and metabolism in a number of ways, especially the photosynthesis (Pn). As Pn is an important factor affecting productivity, the study on its mechanism is still a hot issue in the field of plant physiology and ecology. Pn, however, is mainly restricted by stomatal or non-stomatal factors, and it has not been determined yet. This paper mainly discussed the methods for calculating the stomatal and non-stomatal limit values (Ls and Ci (sub-stomatal CO2 concentration)/gs (the stomatal conductance)), stomatal and non-stomatal limitations under different stresses and the effects on Pn: ① We summarized the methods for calculating the (relative) Ls and Ci/gs values, which could be the basis for judging the main restriction factors; ② We classified the external stresses and summarized the achievements from the aspects of manual controlling conditions (water, salt-alkali and multi-factor stresses) and natural conditions of the previous studies; ③ We analyzed the impact ways of stomatal and non-stomatal factors on Pn. The features of the Ls and Ci/gs, values and the mechanisms of one species at different growth and development stages and in different habitats (hydrothermal, salty, nutrient, and artificial and natural conditions) were explored and discussed, and this will be the key trend and direction for researching. References | Related Articles | Metrics

Oasis Ecology

Select

Effects of Different Irrigation and Fertilization Conditions on Soil N2O Emission from Oasis Farmland WANG Yong, ZHAO Cheng-yi 2018, 35 (4):  938-944.  doi: 10.13866/j.azr.2018.04.23 Abstract ( 16 )   PDF (843KB) ( 0 )   The effects of soil drying-wetting alternation on nitrous oxide (N2O) emission from oasis farmland were analyzed, which could provide the basis for optimizing irrigation and fertilization and reducing N2O emission of oasis farmland. A laboratory incubation experiment was performed to determine the effect of soil drying-wetting alternation on its N2O emission from oasis farmland in arid area. The 100 g dried soil was placed in a 730 mL mason jar, then the mason jar was placed in a 25 ℃ incubator, and the nitrogen content and soil moisture content were strictly controlled through connecting a syringe with a three-way valve to extract gas from the mason jar. The result are as follows: ① Soil drying-wetting alternation influenced significantly the cumulative N2O emission of oasis farmland soil. Without fertilization, the cumulative N2O emission of dryly-treated soil was 1.28 times of that of wetly-treated soil; ② Compared with non-nitrogen treatment, fertilization promoted significantly the soil N2O emission, the highest N2O emission occurred after nitrogen was applied for 0-4 days, and then the soil N2O emission was reduced obviously; ③ The N2O emission rate of the wetted soil was significantly higher than that of the dried soil after nitrogen was applied. The cumulative N2O emission of wetted soil was 2.07 mg·kg-1, and it was 1.16 times of that of dried soil. Therefore, the soil N2O emission from oasis farmland could be reduced by properly prolonging the time interval of drip irrigation and fertilization. References | Related Articles | Metrics

Select

Spatiotemporal Change of the Oasis in Gaochang, Turpan and Its Driving Factors During the Period of 1989-2016 LIU Ya-wen, Abdushalam Jalaliding, Alanuer Aniwaer, MAHPIRAT Nabi 2018, 35 (4):  945-953.  doi: 10.13866/j.azr.2018.04.24 Abstract ( 8 )   PDF (2823KB) ( 0 )   In this paper, the remote sensing images of Gaochang area in Xinjiang in 1989, 1997, 2002, 2009 and 2016 were taken as the data sources to extract the oasis distribution in the study area in recent 27 years. The GIS means, fragstats and related statistical methods were used to investigate the change of time sequence and spatial distribution of the Gaochang Oasis and of the driving factors. The results showed that the Gaochang Oasis was expanded during the study period, the oasis-non-oasis conversion was significant, the oasis area was enlarged from 413.47 km2 in 1989 to 800.48 km2 in 2016, and the oasis expansion was the most significant during the period of 1997-2002. The central area of the oasis was stable, and the area fluctuation occurred mainly in the eastern and western marginal zones. The fragmentation of the oasis landscape was reduced at first and then increased gradually, the landscape shape was tended to be complex, but the overall landscape structure was still relatively single and easily affected by human activities. In the past 27 years, the oasis change was affected by both the natural and human factors, in which the exploitation and utilization of water resources was the precondition of oasis expansion, and the farming population, economic development, agricultural modernization and policy were the main driving factors. References | Related Articles | Metrics

Select

Two Typical Land Use Modes in the Manas River Basin HE Ke, WU Shi-xin, ZHOU Hong-fei, YANG Zhong-hui, YANG Yi 2018, 35 (4):  954-962.  doi: 10.13866/j.azr.2018.04.25 Abstract ( 823 )   PDF (3197KB) ( 609 )   Xinjiang has two basic management modes, i.e. the “farm management mode” developed by Xinjiang Production and Construction Corps and the “local mode” formed by local governments. The comparison and analysis of the differences between the two typical land use modes is of great significance for understanding the effects of different human activities on land use. In this paper, a case study on two typical land use modes in the Manas River Basin in Xinjiang during the period of 1970s-2015 was carried out, and the land use dataset for the drainage basin was constructed. Moreover, the differences between the farm management mode and the local mode in land use change pattern and landscape pattern were investigated by using the land use index and landscape pattern index. The results are as follows: ① The differences of land use change between the two modes were mainly in the change of farmland and construction land, that is the change of farmland in state farms was more significant, but the change of construction land in local areas was more significant; ② Independent management mode was implemented in the local areas where the field size was small and the degree of fragmentation was high. In the state farms, however, the scale of land use was large, and the management was unified, the land consolidation frequency was high, land plots were constantly integrated, and the landscape pattern was tended to be simple; ③ compared with the local communities, there were the significant differences in land use change degree and landscape pattern. The difference was mainly caused by the different corps and the different land management modes. The analyzed results of the differences of land use change between the state farms and the local areas could be referred for the rational land use and regional sustainable development. References | Related Articles | Metrics

Select

Evaluation on Oasis Ecological Security in the Central-northwest Part of the Tarim Basin HE Zhen-zhen, WANG Hong-wei, YANG Sheng-tian, LIU Xiang-yun, WANG Pan, WANG Hui 2018, 35 (4):  963-970.  doi: 10.13866/j.azr.2018.04.26 Abstract ( 693 )   PDF (1400KB) ( 605 )   It is an important precondition for regional sustainable development to maintain the ecological security in oasis. In this paper, an evaluation index system was developed from the aspects of structure, functions and benefits of oasis ecosystem in the Ogan-Kuqa river oasis. The status and trend of ecological security in the oasis during the period of 2005-2014 were calculated and analyzed with the triangle model, and the affecting factors were analyzed by grey correlation analysis. The results showed that: ① The non-structural index (NSI) of the ecosystem was decreased year by year, which indicated that the components of the ecosystem structure system became more and more rational during the period from 2005 to 2014; the non-functional index (NFI) of the ecosystem was in a fluctuating trend; the ecosystem beneficial index (BI) was increased from 0.08 in 2005 to 0.69 in 2014, which indicated that the economic benefits, social benefits and ecological benefits of the oasis ecosystem were continuously improved; ② During the period from 2005 to 2014, the ecological security in the Ogan-Kuqa river oasis experienced the insecure and weak security statuses; the ecosystem in the oasis was not safe during the period of 2005-2010, the NFI, NSI and BI were in the high, medium and low ranges respectively. During the period of 2011-2014, the security of ecosystem in the Ogan-Kuqa river oasis was weak; ③ The two main factors that affected the ecological security in the Ogan-Kuqa river oasis during the period of 2005-2014 were the soil-water coordination and the afforestation area, and their correlation degree and weight were relatively high. Therefore, in order to realize the stability and the sustainable development of the oasis, it is necessary to return grain plots to forests and grasslands according to the local conditions. The results could provide the scientific basis for maintaining and further improving the ecological environment in oasis. References | Related Articles | Metrics

Others

Select

Diversity of Cultivable Fungi in Topsoil in the Degenerated Wild Fruit Forests in Ili CHEN Jie-zuo, WU Nan, ZHANG Bing-chang, RONG Xiao-ying, HU Wen-ge, ZHANG Yuan-ming 2018, 35 (4):  971-976.  doi: 10.13866/j.azr.2018.04.27 Abstract ( 9 )   PDF (1074KB) ( 0 )   The wild fruit forests in the Tianshan Mountains, Xinjiang are one of the areas where deciduous fruit trees are originally cultivated in the world, they have the large area and are the most primitive, densest and relatively rare in Eurasia. In recent years, the wild fruit forest ecosystems have been seriously damaged due to the large-scale human development, and the species diversity was decreased. Current research on wild fruit ecosystem focuses mainly on the aboveground biomass and its related aspects, but the microbial change in groundwater is paid little attention to. The objective of this study was to evaluate the diversity of cultivable fungi isolated from topsoil under health fruit trees (H soil) and diseased fruit trees (D soil) in a degenerated wild fruit forest. Dilution plate technique and 18s rDNA sequence analysis were applied to obtain the sequences of 25 difference strains isolated from the degenerated wild fruit forest, which were subsequently submitted to GenBank and compared with the known sequences to build up a phylogenetic tree. Results revealed that: ① These strains were clustered into 3 subdivisions, 6 classes, 8 orders, 11 families and 11genera; ② The dominant genera of the H soil was Penicillium, while Penicillium and Fusarium were the majority of the D soil, the endemic genera of H soil were Clonostachys and Purpureocillium, but Phoma and Leptosphaeria existed only in the D soil; ③ The Shannon-Wiener diversity index of the H soil was 2.10, it was higher than that of the D soil (1.98), the evenness index of the H soil was 0.91, and it was higher than that of the D soil (0.79). The biological characteristics of these cultivable fungi isolated from the wild fruit forest need to be further studied so as to be better applied in the soil pest control under the wild fruit forests. References | Related Articles | Metrics

Select

Diversity of Bacterial Communities in Rhizosphere Soil of Peganum harmala L.in Desert Steppe CHENG Lin, CHEN Ji-xiang, LI Yan-lin, WANG Yong-gang, ZHOU Yong-tao, ZHANG Yan 2018, 35 (4):  977-983.  doi: 10.13866/j.azr.2018.04.28 Abstract ( 9 )   PDF (1362KB) ( 0 )   Peganum harmala L.is strong in resistance against severe environment,such as drought and low temperature.Plants play an important role in maintaining the local ecological environment.In order to understand the mechanism of ecological adaptation and interaction with environment,the characteristics of bacterial communities in rhizosphere soil of P.harmala in a desert steppe in Baiyin,Gansu Province were studied using the high-throughput sequencing and culture-dependent method,and they were compared with those of surrounding soil.The results showed that the bacterial communities in the rhizosphere soil were consisted of 30.01% Actinobacteria,23.98% Proteobacteria,11.53% Bacteroidetes and 10.19% Acidobacteria.The dominant soil bacterial community in the surrounding desert steppe was composed of 55.05% Actinobacteria,21.11% Proteobacteria and 6.07% Acidobacteria.The cultivable bacterium group included Firmicutes,Proteobacteria and Actinobacteria.In the rhizosphere soil,the dominant bacteria were 23.53% Brevibacterium, 23.53% Bacillus,17.65% Pseudomonas and 11.76% Brevundimonas. The dominant populations of bacteria in the surrounding soil were 37.50% Arthrobacter, 18.75% Bacillus and 12.50% Pseudomonas. The difference of bacterial communities between the rhizosphere soil of P.harmala and its surrounding desert steppe soil was significant.The bacteria numbers and diversity index in the rhizosphere soil were significantly higher than those of the surrounding desert steppe soil.The results provided the scientific basis for exploring the interaction between the desert steppe plants and their rhizobacteria,and also for understanding the roles of the rhizobacteria in promoting plant growth and soil material transformation. References | Related Articles | Metrics

Select

Carbon Density and Its Distribution Pattern of Ecosystem in Saline Region LI Dian-peng, SUN Tao, YAO Mei-si, LIU Sui-yunhao, WANG Li-ping, WANG Hui, JIA Hong-tao 2018, 35 (4):  984-991.  doi: 10.13866/j.azr.2018.04.29 Abstract ( 712 )   PDF (1262KB) ( 544 )   Saline vegetation in arid area is widely distributed,and the plant species are numerous,which plays an important role in the ecosystem carbon balance and regional climate regulation.In this paper,the field investigation in the Dabancheng saline lake area in Xinjiang and the indoor analysis were carried out so as to study the characteristics of carbon density distribution of saline vegetation and soil in this arid area.The results showed that the soil organic carbon density decreased with the increase of soil depth,it varied in a range of 7.55-15.75 kg·m-2 within 0-100 cm soil layer,and its average value was 12.54 kg·m-2 and accounted for 97.84% of the total organic carbon density of plant community and soil.Lycium ruthenicum and Halimodendron halodendron are the dominant species in the halophyte communities,their average aboveground biomass was 261.38 g·m-2 and accounted for 70.49% of the total biomass.The biomass of herbaceous plant community was 109.45 g·m-2.The aboveground biomasses of shrub and herb layers were significantly higher than the biomasses of their litter layers (84.81±9.22) and (79.76±8.61) g·m-2.The underground biomass of halophytes decreased with the increase of soil depth,and it in 0-100 cm soil layer was 77.74 g·m-2.The carbon density of total biomass of halophytes was 276.48 g·m-2,in which the aboveground,litter and underground biomasses accounted for 62.09%,25.75% and 25.75% of the total respectively.The carbon density of aboveground vegetation and litters was significantly higher than that of herbaceous plants,that of root biomass varies and its 96.55% concentrated in 0-50 cm soil layer.The average carbon content of aboveground,underground and litter of halophytes was 43.09%,which was 13.80% higher than the value estimated with empirical coefficient (50%) and produced high deviation in estimating vegetation carbon reserve. References | Related Articles | Metrics

Select

Farmers’ Adaptive Capability Against Drought in Semiarid Area in Central Gansu Province: A Case Study in Yuzhong County WANG Ting, SHI Yu-zhong, LIU Qian, WEN Teng-fei, YANG Xin-jun 2018, 35 (4):  992-1000.  doi: 10.13866/j.azr.2018.04.30 Abstract ( 510 )   PDF (1239KB) ( 366 )   Drought is one of the scientific issues of concern in the context of global climate change,it not only affects the agricultural production,threatens farmers’ livelihoods,and even restricts the rural sustainable development. It can help us to improve farmers’ livelihood sustainability to study farmers’ adaptive capability against drought. In this paper,a case study on farmer’s adaptive capability against drought in Yuzhong County in central Gansu Province was carried out,and an evaluation model was established by means of concept of the social-ecological system framework (SES). Based on the surveyed data of farmers’ livelihood situation,the farmers were divided into the subsidy-dependent,agricultural-oriented,industrial-oriented,by-business and professional types,the adaptive capability of rural farmers in Yuzhong County was quantitatively assessed,and the factors affecting farmers’ adaptive capability were analyzed. The results showed that: ① The types of farmers were diversification,among them the proportion of industrial-oriented farmers was the highest,and that of professional farmers was the lowest; ② The overall stability of farmers’ adaptive capability against drought was poor,and there was a significant internal difference. The stability of types of farmers’ adaptive capability against drought was in an order of subsidy-dependent type>agricultural-oriented type>industrial-oriented type>by-business type>professional type; ③ The factors restricting farmers’ adaptive capability against drought were mainly the drought loss,natural capital,farmers’ cognition,water-saving irrigation and social capital. References | Related Articles | Metrics