Arid Zone Research

Progress of Wetland Researches in Arid and Semi-arid Regions in China

GOU Qian-qian, QU Jian-jun, WANG Guo-hua, XIAO Jian-hua, PANG Ying-jun

2015, 32 (2): 213-220. doi: 10.13866/j.azr.2015.02.01

Abstract ( 2028 )

PDF (1453KB) ( 1671 )

Wetlands in the arid and semi-arid regions in northwest China are of significance, and play an important role in global climate regulation, water holding, carbon cycle and biodiversity conservation. Thus, summarizing and analyzing the current status and progress of wetland researches is important for ecological conservation and environmental management. In this article, the authors summarized the progress of wetland researches in arid and semi-arid regions in 5 aspects, including formation, evolution, types and distribution of wetlands, plant community of wetlands, ecological effect of landscape pattern change and driving force of wetlands, carbon and nitrogen cycles of wetlands, and degradation and recovery of wetlands, then pointed out the lacks of present researches on wetlands. In the basis the above-mentioned, the authors suggested that strengthening the researches on dynamic change of plant community and landscape pattern, the response mechanism of dynamic process on the driving force, carbon and nitrogen cycles, and theory and technology system of degradation and restoration for wetlands.

References | Related Articles | Metrics

Effects of Different Land Use Patterns on Enzyme Activity of Aeolian Sandy Soil

HUANG Jing, WU Xiang-yun, SHAN Bao-qi, WANG Mei-ting

2015, 32 (2): 221-228. doi: 10.13866/j.azr.2015.02.02

Abstract ( 959 )

PDF (757KB) ( 699 )

Taking Manghailinzi village of Liuhe basin in the Zhangwu county, Liaoning Province as an example, the effects of different land use patterns on the six kinds of enzyme activities of aeolian sandy soil of the area were studied. The results showed that enzyme activity was at the lowest level because of sparse vegetation and few creatures in bare land. Enzyme activity of flood land was also at the lowest level because of the special geographical location of flood land where the soil was easily washed by river water. The flood land is not suitable for reclamation of cultivated land because farming would affect the releasing of flood water. Enzyme activity of farmland in non-flood land was in the middle level because cultivation and harvesting exacerbated soil erosion process and reduced the enzyme activity. The land was suggested to lie fallow. Enzyme activity of natural grassland was at the higher level, which illustrated natural grassland can improve the aeolian sandy soil enzyme activity to a certain extent. Due to soil surface litter and humus accumulation, adequate nutrition and better hydrothermal conditions, the enzyme activity in forest land was at the highest level. Therefore, the effect of improving sandy soil enzyme activity was the most obvious through planting poplar.

References | Related Articles | Metrics

Variation of Water Suitability for Special Fruit Trees in the Dryland Area of Southeast Gansu in Recent 30 Years

YAO Xiao-ying, ZHANG Qiang, WANG Jing-song, WANG Ying, LI Yue

2015, 32 (2): 229-234. doi: 10.13866/j.azr.2015.02.03

Abstract ( 662 )

PDF (1686KB) ( 1107 )

Basing on the fruit trees’ phonological observation data from 1998 to 2010 and meteorological data from 1981 to 2010 in main planting regions in the dryland area of southeast Gansu, the model of water suitability for fruit trees growing was set up with the FAO Penman-Monteith formula (1998 edition) and crop coefficient, the water requirement of fruit trees in different growth periods from 1981 to 2010 was calculated. The results showed that the drought in spring appeared more and more severe compared with other seasons during the period of fruit growing since 1980s.The water suitability of whole growth periods decreased with the time under the background of climate warming, the water supply to apple and grape was under good conditions, which annual mean water suitability was above 0.50; the water supply to big cherry and peach was under bad conditions, which annual mean water suitability was 0.41 and 0.47, respectively. The water suitability for 4 kinds of fruit trees decreased at the initial growth stage. The grape was with an optimal moisture condition, followed by apple. The water suitability of big cherry and peach was less than 0.40 since 2010s, and the contradiction was marked between supply and demand of water during initial growing of big cherry. The water suitability of grape and apple increased at the vigorous growth stage since 2010s. The amount of water requirement for peach and big cherry in fruit trees growing was lacking, and the water suitability of big cherry was only 0.31, with increased water stress because of the spring drought. The water suitability increased basically at the last growth stage, and the precipitation was more than the amount of water requirement for grape with the water suitability of above 1.0, 1.0 for apple. The precipitation was suitable for apple; it was above 0.5 for big cherry and peach. The precipitation could also satisfy requirement. The established model can assess the environmental climate of fruit trees and provide scientific suggestion for planting regions of fruit trees in the dryland area of southeast Gansu.

References | Related Articles | Metrics

Effects of Medlar Planting on Active Organic Carbon and Carbon Pool Management Index in Secondary Salinized Soil

LI Yin-ke, MA Quan-lin, WANG Yao-lin, SUN Tao, JIN Hu-jia, SONG De-wei, DU Juan

2015, 32 (2): 235-239. doi: 10.13866/j.azr.2015.02.04

Abstract ( 764 )

PDF (1172KB) ( 833 )

This study explored effects of medlar planting on contents of total organic carbon (TOC), active organic carbon (AOC), non active organic carbon (NAOC), and carbon pool management index (CPMI) in secondary salinized soil and compared those contents against what in abandoned salinized agricultural land. The result showed that the contents of TOC, AOC, and NAOC increased by 41.6%, 46.5% and 51.1%; 57.1%, 57.9%, and 54.4%; and 24.0% and 33.2%, 47.3%, respectively in the soil depth of 0-100 cm after medlar planting for 4, 7 and 11 years. The largest increases appeared at the soil depths of 0-10 cm and 60-80 cm. Carbon pool activity and carbon pool activity index had a little increase, carbon pool index (CPI) and CPMI were significantly increased after medlar planting in secondary salinized soil. The soil quality was improved effectively. Correlation analysis showed that the soil fertility improvement and the decrease of soil salinization were closely related to TOC, AOC, NAOC and CPI. The four indices could be used as the indicators to reflect the soil quality improvement of secondary salinized soil.

References | Related Articles | Metrics

Application and Development of Conservation Tillage Techniques in the Loess Plateau

KONG Wei-ping, CHENG Zi-yong, ZHANG Rui, HE Zhao-quan, HE Zheng-qian, ZHANG Xiao-xia, LIU Jing-xia, GAO Yang

2015, 32 (2): 240-250. doi: 10.13866/j.azr.2015.02.05

Abstract ( 714 )

PDF (1308KB) ( 1372 )

In the past several decades, the conservation tillage techniques in the Loess Plateau has evolved from single translating and imitating advanced foreign technology into specific techniques system combined with the many advantages (distinctive system, strict design according to local condition and advanced developmental idea with gradually inheriting and reform).On the context of global change, the role of conservation tillage techniques is also critical in terms of mitigation of greenhouse emissions in field-scale. Hereby, this paper summarized the design ideas and main contents of conservation tillage techniques in the Loess Plateau, and also illustrated the internal mechanism of the processes of field water ecology and erosion prevention effect under conservation tillage techniques. This paper analyzed emphatically the effect and cause of conservation tillage techniques on soil temperature, soil physical-chemical properties, yield performance and water use efficiency. Finally, this paper pointed out deficiency and limitation of current in aspects of exploitation, demonstration and extension of current conservation tillage techniques in dryland farming in the Loess Plateau. This paper concluded that the conservation tillage techniques combined with ridge-furrow plastic film mulching is main route of dryland farming in the Loess Plateau. All of these aspects were discussed aiming to provide theoretical guidance for sustainable management and sustainable exploitation of rainfed agricultural ecosystem in the Loess Plateau.

References | Related Articles | Metrics

Dry Matter and Water Use Efficiency of Annual Forage Crops in the Loess Plateau

ZHANG Qing-ping, TIAN Li-hua, LIU Yuan-bo, JIANG Hai-liang, SHEN Yu-ying

2015, 32 (2): 251-257. doi: 10.13866/j.azr.2015.02.06

Abstract ( 675 )

PDF (1293KB) ( 810 )

Annual forage crops are important feeding sources in early spring and winter seasons in areas of the Loess Plateau, with water use efficiency being an important indication of crop adaptability to local climate environment. In a rainfed area of eastern Gansu, dry matter, soil water deficit and water use efficiency of annual forage crops were determined. Annual forage crops were maize (Zea mays), Sudan grass (Sorghum sudanense), soybean (Glycine max), small millet (Setaria italica), millet (Panicum miliaceum), common vetch (Vicia sativa), pea (Glycine max), oat (Avena sativa) and spring wheat (Triticum aestivum). The results showed that soil water deficit of annual forage crops presented a ‘V’ curve, with the exception of Sudan grass; water use efficiency of spring wheat was higher than other crops at 6 weeks after emergence, whereas maize was the most efficient at 15 weeks after emergence. Variable amplitude of water use efficiency in millet and small millet was low. The crops of maize, spring wheat, small millet and millet were optimum under spring-sown condition in the Loess Plateau.

References | Related Articles | Metrics

Plant Community Diversity of Steppification Desert in West Ordos

WANG Le, ZHAO Li-qing, CHEN Yu, PEI Zhi-li

2015, 32 (2): 258-265. doi: 10.13866/j.azr.2015.02.07

Abstract ( 810 )

PDF (1825KB) ( 1058 )

The West Ordos,which is located in the core region of the Alashan-Ordos biodiversity center,is one of the key areas for biodiversity researches. In recent years, mineral resources are exploited in a large scale, industrial zones are expanding all the time and grazing continuously happens. The impacts of anthropogenic factors lead to a high degree of regional habitat fragmentation. If we take the change in the global climate into consideration , all of the above seriously threat to community diversity. In order to repair the broken habitat and construct a reasonable vegetation cover, we must know more about the composition of the native communities, especially we need to master the difference and relations between different layers of the communities and the desert communities with the neighbors. Here we use the field community investigation method to investigate and analyze 53 plots from 12 plant formations in this region. The results indicate that ① The west Ordos desert vegetation includes a number of mono-type and oligoro-types genera, such as Tetraena mongolica, Helianthemum ordosicum, Ammopiptanthus mongolicus, Potaninia mongolica, Tugarinovia mongolica. They not only increased the diversity of plant communities in West Ordos, but also reflected the uniqueness of plant diversity. ② Shrubs in West Ordos steppe desert, in terms of the composition of the life form spectrum, is 13.1% higher than that of adjacent desert steppe and become constructive or dominant species of communities in different habitats. Most of them are constructive or dominant species in different habitats and sufficiently reflect the feature of steppe desert. ③ By comparison of plant life form spectra between steppification desert and desertification steppe, shrub is 13.1% higher in steppification desert than desertification steppe. In terms of the water ecological type spectrum, the proportion of strong xerophytes is 15.9% higher in the desertification steppe nearby, although typical xerophytes are the dominant plants here. ④ There are many kinds of plant community types in West Ordos steppification desert. Species diversity of typical steppification desert communities (such as Form. Zygophyllum xanthoxylon, Form. Potaninia mongolica, Form. Ammopiptanthus mongolicus, Form. Tetraena mongolica, Form. Helianthemum soongoricum, Form. Artemisia ordosica) has a higher diversity and is of stability due to interactions between the herb layer and shrub layer. ⑤ Compared with desertification steppe, β-diversity is higher in West Ordos steppification desert communities. For this reason, West Ordos steppification desert can accommodate more communities for co-existing together.

References | Related Articles | Metrics

Change of Vegetation Cover Based on NDVI at Wuliangsu Lake Wetland

YUE Dan, LIU Dong-wei, WANG Li-xin, YI Ta-na

2015, 32 (2): 266-271. doi: 10.13866/j.azr.2015.02.08

Abstract ( 865 )

PDF (1232KB) ( 1221 )

Wetland ecosystem, called as the kidney of the earth, is the main part of terrestrial ecosystems. Wuliangsu Lake, as a large-scale, multi-function lake-wetland in the semi-desert area of China, has high ecological and social value. Vegetation cover is an important indicator used to monitor vegetation change for evaluating terrestrial environment. In this paper, remote sensing images from Landsat TM were used as data sources to study the change characteristics of Wuliangsu Lake in 3 periods (1987, 2000 and 2010).The normalized difference vegetation index ( NDVI) was calculated based on the TM satellite image data, and was in turn used to estimate vegetation cover at Wuliangsu Lake.The results showed that vegetation coves increased from south to north across Wuliangsu Lake during 1987 to 2010. The proportion of <20% vegetation cover decreased from 30.81% to 16.57%. The proportion of 20%-50% vegetation covers was not significantly changed with 14.50%. The proportion of high vegetation cover (>50%) increased significantly, which raised from 15.68% to 31.05%. In the whole region, the area of desertification land was decreased, while the farmland area was increased gradually. Climate change and anthropogenic factors are two driving forces in the change of vegetation cover. Human factors not only include the impact of human activities on vegetation boimass, but also in terms of the impact of different types of land use and related policies; climatic factors are mainly temperature and precipitation.

References | Related Articles | Metrics

Multifactor Analyses of Impacting Net Photosynthetic Rate for 27 Species in the Xillinhot Steppe

WANG Ran, LI Su-ying, REN Li-juan, ZHAO Yuan-yuan, WU Xiao-xia, FAN Qiang

2015, 32 (2): 272-278. doi: 10.13866/j.azr.2015.02.09

Abstract ( 727 )

PDF (812KB) ( 1107 )

The key impact factors of plants’ Pn (net photosynthetic rate) in the typical steppe were related with the fluctuation and stability of grassland productivity. This research tested the photosynthetic indexes and their environmental factors of 82 plants, 27 species in 22 sample plots. Pearson correlation analysis, multiple regression analysis, path analysis and decision coefficient were used to analyze the relationships between Pn and its impact factors. The results showed that the relationships between Pn and Gs(stomatal conductance), Tr(transpiration rate) of the steppe plants were significant positive correlation in Xillinhot steppe; Pn and Ci(intercellular CO₂ concentration) had a significant negative correlation; Pn and WUE(water use efficiency) has a linear relation. Among the environmental factors which influenced the steppe plants, Pn was increased with RH(ambient humidity), while Ta(air temperature) did not significantly influence Pn. Path analysis indicated that WUE, Tr, Gs and RH were major factors of impacting Pn for grasses. Decision coefficients showed that Tr, WUE, Gs and Ci promoted the decision variables of Pn, but Ta and RH were the restrictive factors for the photosynthesis of plants in the typical steppe. This research showed that Tr, WUE, Gs and RH were the main impact factors for Pn. The results in the paper could offer a basic analysis on the impact factors of grass productivity in the steppe area.

References | Related Articles | Metrics

Effects of NaCl Treatments on Growth and Ecophysiological Characteristics of Populus euphratica

LU Yan, LEI Jia-qiang, ZENG Fan-jiang, XU Li-shuai, PENG Shou-lan, LIU Guo-jun

2015, 32 (2): 279-285. doi: 10.13866/j.azr.2015.02.10

Abstract ( 666 )

PDF (2010KB) ( 943 )

A pot experiment was conducted to study the effects of different NaCl concentrations (0, 50, 100, 200 mmol·L^-1 and 400 mmol·L^-1) on the growth, leaf hydrogen peroxide (H₂O₂), malonaldehyde (MDA) content, superoxide dismutases (SOD), catalases (CAT), peroxidase (POD), ascorbate peroxidase (APX) enzymes activity, water potential, soluble sugar and proline contents of Populus euphratica. The results showed that plant heights were significantly inhibited under 200 mmol·L^-1 NaCl treatment compared with control; Basal stem diameter were significantly inhibited under 400 mmol·L^-1 NaCl treatment compared with control; Crown area, leaf dry mass and branch dry mass decreased remarkably under NaCl concentration ≥100 mmol·L^-1 compared with control level; Root dry mass decreased with the increasing in NaCl concentrations. Root shoot ratio decreased markedly under NaCl concentration ≥200 mmol·L^-1 compared with control. H₂O₂ and MDA content increased with the increasing in NaCl concentrations. SOD, POD, CAT and APX activities in leaves of P. euphratica increased compared with control lever at low NaCl concentrations (50 mmol·L^-1), whereas SOD, POD and APX activities began to descend under NaCl concentration ≥100 mmol·L^-1 compared with control level. Water potential in leaves of P. euphratica reduced with the increasing in NaCl concentrations. Being treated for 90 d, soluble sugar decreased with the increasing in NaCl concentrations. Proline content in leaves of P. euphratica first increased and then decreased compare with control level.

References | Related Articles | Metrics

New Record of Bryum Hedw. in Xinjiang

PATIGUL Omar, MARZIYA Ablimit, RABIYE Gupur, ZHAO Jian-cheng, MAMTIMIN Sulayman

2015, 32 (2): 286-289. doi: 10.13866/j.azr.2015.02.11

Abstract ( 678 )

PDF (2010KB) ( 734 )

Using classical taxonomic method, we identified the species of mosses collected from different regions of Xinjiang. The results showed that Bryum apiculatum Schwaegr. and Bryum paradoxum Schwaegr. were newly recorded species in Xinjiang. Although Bryum algovicum Sendt. ex C.Müll. and Bryum atrovirens Brid. were recorded in the Flora Bryophytorum Sinicorum, we did not put them in the Checklist of Mosses in Xinjiang, because of lacking the existing specimens. In this study, two Bryum species were confirmed to be distributed in Xinjiang. The taxonomic features and geographical distribution of these species are identified and the graphics of 3 species are made. The specimens are deposited in the herbarium of Xinjiang University (XJU).

References | Related Articles | Metrics

Estimate of the Climate Change in Alpine Mountains Areas based on Statistical Downscaling Method

MU Zhen-xia, JIANG Hui-fang

2015, 32 (2): 290-296. doi: 10.13866/j.azr.2015.02.12

Abstract ( 718 )

PDF (2103KB) ( 1012 )

Estimating the climate changes over alpine mountains areas is critical for understanding regional water resources changes and guiding reasonable water utilization and development. Based on the observed hydro-meteorological data, NCEP/NCAR reanalysis data and HadCM3 outputs, the climate change (2020-2090) in alpine mountains areas is projected by statistical downscaling method. The results show that the performances of calibration SDSM model are basically acceptable. On the whole, future precipitation in Xiehela station showed a decreasing trend, especially in July and August. However, precipitation fluctuation is complex under different climate change scenarios. The future temperature will be continuously increased, especially in the 2070s. Due to precipitation reduced, glaciers and snow reserves will be affected in the future. With the increasing warming of the study area, it would accelerate the glacier and snow melt and have a greater impact on water resources supply to the rivers in the alpine mountain region. At last, it will affect the regional socio-economic development and aggravate the contradiction of different water use sectors.

References | Related Articles | Metrics

Analysis of the Impact Factors of Atmospheric Transparency in Xinjiang

HU Lie-qun, LI Shuai, ZHENG Bei-wen

2015, 32 (2): 297-303. doi: 10.13866/j.azr.2015.02.13

Abstract ( 756 )

PDF (1333KB) ( 1154 )

Based on the direct radiation data and related meteorological and pollutant data from 1961-2012 in Urumqi and Kashgar,this study investigated the characteristics and the annual and the seasonal variations of the atmospheric transparencies in the two regions. The atmospheric transparencies in Urumqi and Kashgar presented decreasing trends in general in the last 52 years and accelerated in the both regions since 1990s. The analysis of the impact factors of the atmospheric transparency proved that there was a negative correlation between the atmospheric dust content and the atmospheric transparency. Compared with in a sunny day, the daily peak value of the atmospheric transparencies decreased by 35.0%, 61.6% and 96.9% in the dust, the blowing-sand and the sand-stormy days, respectively. Vapor pressure also had a negative correlation with the atmospheric transparency. The cloud amount had more effects on the atmospheric transparency in Kashgar than in Urumqi. The atmospheric transparency can decrease by 61.5% in cloudy days in Kashgar. The cloud height had a negative correlation with the atmospheric transparency. At the beginning of the 1990s, the atmospheric transparency in Urumqi sharply attenuated. The peak values of the atmospheric transparency appeared in autumn instead of in winter as used to be in both Urumqi and Karshgar which indicated that the air pollution made the atmospheric transparency getting worse under the process of urbanization. NO₂ and SO₂ significantly affected the atmospheric transparency while PM₁₀, PM_2.5, PM_1.0 and BC had certain effects on the atmospheric transparency. O₃ had no effect on the atmospheric transparency.

References | Related Articles | Metrics

Impact of Caragana microphylla Nabkhas on Airflow Structure and Wind Erosion in Inner Mongolia Plateau

AN Jing, HASI Eerdun, DU Hui-shi, YANG Yi , ZHANG Ping

2015, 32 (2): 304-312. doi: 10.13866/j.azr.2015.02.14

Abstract ( 680 )

PDF (2202KB) ( 783 )

Caragana microphylla Nabkhas is the main aeolian deposit in the agro-pastoral transitional zones in southeast Inner Mongolia Plateau. Field investigations on the airflow structure and wind-sand flow of some typical nebkhas showed that the direction and intensity of the airflow and the sediment transport rate varied with the different positions of the nebkhas. The airflow around the nebkhas and over the top of the nebkhas merged together at leeward and turbulences were developed thereafter with a vertical range of the height of the nebkhas and a horizontal range of 1.5 times of the height of the nebkhas. The wind velocity increased at windward and kept increase at the north and the south sides of the nebkhas, then reached the lowest velocity at leeward and then gradually increased back to the wildness wind speed. The main wind direction affected the airflow at leeward. Under the different wind directions, the wind velocity profile around the nebkhas showed non-logarithmic regularity. The wind velocity at the height of 0.3-0.6 m changed under different wind directions at the south side of nebkhas. In addition, sediment transport rates at the windward, the north and south the sides of the nebkhas were consistent with the change of the velocity. However, sediment transport rate at leeward changed because of the turbulence. Sediment transport rate decreased with the increase of the height at windward and at the both sides of the nebkhas, but showed no regularity at leeward.

References | Related Articles | Metrics

Climate Change in the Middle and the Lower Reaches of Kaidu River and Its Impact on the Runoff

LI Jian-tao, HAIMITI Yimiti, WEI Bin, ZHANG Yi-qiong

2015, 32 (2): 313-320. doi: 10.13866/j.azr.2015.02.15

Abstract ( 691 )

PDF (3253KB) ( 846 )

Based on the data from Dashankou and Yanqi hydrometeorological stations in the Kaidu River Basin from 1960 to 2010, this study analyzed the features of the temperature and precipitation changes and the responses of the runoff to the climate change using trend analysis, anomaly analysis, multiple regression and linear fitting. The results showed that the temperature in Kaidu River Basin presented an increasing trend in general in recent fifty years. The temperature increased by 1.08 ℃ at Dashankou station and 1.71 ℃ at Yanqi station. The temperature increased in winter was obvious than the increase in summer at Yanqi station while no obvious seasonal variations at Dashankou station. The annual precipitation fluctuations were significant at both stations. The precipitation presented a significant increase at Dashankou station and achieved the fifty-year peak value in 1998. Both temperature and precipitation affected the runoff of Kaidu River. The correlation of the runoff with the temperature and the precipitation was obvious at the upper of the Dashankou station but not the part of the river in Yanqi County. In general, runoff variation had positive correlations with the temperature and the precipitation.

References | Related Articles | Metrics

Diagnostic Analysis of the Effect of Planet Boundary Layer on a Hail Event in the Northeastern Edge of Qinghai-Tibetan Plateau

ZHANG Zhi-xian, ZHANG Qiang, TAO Ji-chun

2015, 32 (2): 321-328. doi: 10.13866/j.azr.2015.02.16

Abstract ( 779 )

PDF (2260KB) ( 699 )

The paper studied a heavy hail disaster occurring on the northeastern edge of Qinghai-Tibetan Plateau on 10th May 2012 based on an analysis to planet boundary layer and land surface process by using WRF V3.4 model. The results indicated that the hail disaster was caused by a secondary circulation because of the prior energy accumulating. The hail disaster was a extraordinarily serious calamitic event with the characteristics of a short-duration, high intensity, breaking out suddenly and multi-disasters accompanied with the synoptic-scale systems. At the time, the maximum height of convective boundary layer (CBL) in the early stage became thicker as a result of the energy accumulating, although the height was greatly lower than the average one. All of this demonstrated that the thermal convection environment of boundary layer maybe was the important energy source for the convection of weather development. Judging from the distribution of convective available potential energy (CAPE), the energy gradient was pretty and the thermodynamic system was extremely in homogenous. The latent heat flux and sensible heat flux value exceeded the average before the disaster. The height of absolute stable stratification, above the conditional unstable stratification in the near surface, was decreased gradually. The lapse rate of potential pseudo-equivalent temperature in conditional unstable layer had the tendency of increasing first and then decreasing, and its peak was 0.88 K·(100m)^-1 at 13:00. In the meanwhile, the horizontal gradient of potential temperature was maximum. The friction velocity exhibited a significant increase before and after this process probably because of the abnormal transfer of turbulent momentum and meso-scale momentum flux.

References | Related Articles | Metrics

Effects of the Landscape Pattern Dynamic Changes on Ecological Service Value —A Case Study in the Central Ningxia Arid Zone

WANG Chong-ling, ZHU Zhi-ling, BAI Lin-bo, CHENG Shu-jie, LU Cai-ling

2015, 32 (2): 329-335. doi: 10.13866/j.azr.2015.02.17

Abstract ( 744 )

PDF (1249KB) ( 1324 )

This study analyzed how the landscape pattern dynamic changes affected the ecological service values in grasslands and arable lands in the central arid zone of Ningxia since 1990s. Hongsibu area,Tongxin county,Haiyuan county and Yanchi county were selected as the study areas and TM images from 1989, 1999, 2006 and 2011 were selected as the main data sources. Remote sensing, GIS and landscape ecology research methods were adopted. The results showed that the areas of the grasslands and the irrigated lands significantly increased in the above mentioned regions, which played an important role in environment optimization. The land use pattern has been greatly changed due to the human activities. The degree of fragmentation and spatial heterogeneity obviously increased, which resulted in ecological environment degradation. Since the beginning of the 21st century, the adoption of the environmental polices such as the implementation of the returning grain plots to forest or grassland, grazing prohibition, water conservation measures and ecological migration engineering improved the quality of the ecological environment and the structure of the land use. Overall, the better the ecological environment, the higher the ecological service value. The ecosystem service value in certain degree reflected the quality of an ecological environment. The results of this study provided theoretical and practical knowledges to the land use policies and the ecological environment optimization.

References | Related Articles | Metrics

Responses of Heavy Metal Variation Patterns to Environmental Changes in the Upper Reaches of Hanjiang River Valley

BIAN Hong-yan, PANG Jiang-li, HUANG Chun-chang, CHA Xiao-chun

2015, 32 (2): 336-341. doi: 10.13866/j.azr.2015.02.18

Abstract ( 871 )

PDF (1934KB) ( 1026 )

Loess-paleosol sequences were recognized as one of the most completed terrestrial records of palemonsoon climate evolution. The chemical parameters and metallic elements were normally used to indicate the soil sources and environmental changes. This study investigated the characteristics of the long-term climate evolution in the upper reaches of the Hanjiang River Valley using the heavy metallic elements variations, which was not commonly adopted by previous researchers. Loess-paleosol soil samples were collected from the first step terrace of the upper reaches of the Hanjiang River Valley. The heavy metallic element contents of Ni、Mn、Cu、Zn、As、Ti、V、Pb in the soil were measured and analyzed as the main climate change indicators. Magnetic susceptibility, Rb/Sr ratio and clay content were selected as the supplement indicators. The results showed that Cu, Ni, As, Pb and Mn contents in the soil were affected by climate changes and the pedogenesis environment and were significantly and positively correlated with the index of Pedogenic (magnetic susceptibility, Rb/Sr ratio and clay fraction of particle-size). Strong pedogenesis made some soluble elements migrate to deeper soil layers, leading to relative enrichment of heavy metals in the paleosol. According to the vertical distribution of the heavy metallic elements, the upper reaches of the Hanjang Valley experienced 5 stages of the climatic changes since the lift of the first step terrace. The climate was warm and humid in the Mid-Holocence except a cold and dry event happened at 6-5 ka B.P.

References | Related Articles | Metrics

Comprehensive Assessment of Desertification Status Based on Remote Sensing and Principle Component Analysis

LIANG Wen-qiong, TIAN Shu-fang, ZHOU Jia-jing

2015, 32 (2): 342-346. doi: 10.13866/j.azr.2015.02.19

Abstract ( 776 )

PDF (961KB) ( 849 )

Because some of the desertification evaluation indices cannot be directly obtained by remote sensing, and simple visual interpretation or direct classification evaluation methods have strong subjectivity, a comprehensive evaluation method of the desertification status based on remote sensing in combination with principal component analysis was put forward. Five desertification evaluation indices were selected following the representative, comprehensive, predominant and operable principles. These indices were directly obtained from inversed ETM⁺ data. Comprehensive evaluation model was set up based on principal component analysis of priori data and the determination of indices weight. The present desertification status of the whole study area was evaluated by the model. Results indicate that the model is more objective than that method of analysis and is more suitable for the desertification evaluation at regional scale. And the evaluation effects of the model reflected the superiority of the remote sensing method at large environmental scale.

References | Related Articles | Metrics

Sand Masses Blocked by Double Nylon Mesh Sand Barriers with Different Intervals

KANG Xiang-guang, LI Sheng-yu, MA Xue-xi, WANG Hai-feng, LEI Jia-qiang, WANG Shi-jie

2015, 32 (2): 347-353. doi: 10.13866/j.azr.2015.02.20

Abstract ( 586 )

PDF (1973KB) ( 1030 )

This study analyzed the deposited sand masses and their spatial distributions in two nylon mesh sand barriers with four different horizontal spaces of 2H、5H、10H and 15H (H represents the distance between two nylon meshes). A sand-control experiment was set up in an inter-dune flat sand sheet in the central Taklimakan Desert. The results showed that there was a weak and negative linear correlation between the deposited sand mass and the distance between two nylon meshes. The meshes of 2H and 5H blocked the largest amount of sand masses while the meshes of 10H blocked the smallest amount of the sand masses. The meshes of 15H blocked the media amount of the sand masses. The results of the experiment were different with what were believed in general. The spatial distribution patterns of the deposited sand masses were obviously varied with the distances between the meshes. The sand masses were mainly deposited at the downwind position in the 2H meshes while the sand masses were blocked in between the meshes and at the downwind positions in 5H, 10H and 15H meshes. The amount of blocked sand masses at the windward side and at the downwind position had negative correlations with the distances between the meshes. However, the blocked sand masses in between the two meshes had positive correlations with the distances between the nylon meshes. The near-surface flow structure affected the amount and the spatial distributions of the sand masses blocked by the nylon meshes but the mechanism of the differentiation was needed to be explored further in the future.

References | Related Articles | Metrics

Habitat Selectivity and Seasonal Variations of Wolves (Canis lupus) in Southeastern Junggar Basin,Xinjiang

HAN Li-li, CHU Hong-jun, WANG Yuan, TAO Yong-shan, GE Yan

2015, 32 (2): 354-360. doi: 10.13866/j.azr.2015.02.21

Abstract ( 814 )

PDF (836KB) ( 877 )

Race samples and control quadrants were used to study habitat selectivity and seasonal variations of wolves in Mt. Kalamaili Ungulate Nature Reserve (MKUNR) of southeastern Junggar Basin,Xinjiang. The results showed that,in spring, wolves preferred to select mountain slope and mountaintop, 900-1 000 m of altitude, with distance of 2 to 4 km to permanent water source, 0.5-1 km to main road, 2-4 km to human community, and the canopy cover was 0.9-1. In summer, wolves preferred to select mountain slope and mountain trench, 900-1 000 m of altitude, with distance less than 2 km to permanent water source, 1.5-3 km to main road, 2-4 km to human community, and the canopy cover was 0.9-1. In winter, wolves preferred to select mountain slope and sand dune, under 800 m of altitude, with distance less than 2 km to permanent water source, 1.5-3 km to main road, 2-4 km to human community, and the canopy cover was 0.5-0.9. Principal component analysis (PCA) showed that habitat selectivity of wolves was mainly affected by human disturbance in spring, by water source in summer, and by food in winter.

References | Related Articles | Metrics

Accessibility of Tourism Transport Based on Link Performance Function—A Case of 3A Tourism Scenic Spots in Xinjiang

QIN Wen-min, ZHANG Xiao-lei, YANG Zhao-ping, LIU Qun, LIU Hua-xian

2015, 32 (2): 361-367. doi: 10.13866/j.azr.2015.02.22

Abstract ( 937 )

PDF (1213KB) ( 1545 )

Tourism transport system is the determinant of tourist destination and its market, it is the basis for optimizing distribution of scenic spots. Accessibility is a potent index and is often used to evaluate the potential ability of region development. Currently, grading approaches of accessibility have been widely used, among them, cumulative time cost grid is most widely used for its intuition and brevity in a practical application. However, the variables of cost function in cumulative time cost grid is too single to reflect the actual accessibility of survey region. To improve the traditional algorithm, a new algorithm has been proposed on the basis of Link Performance Function. In the new algorithm, transportation fees and the actual accessibility was incorporated into the cost function, which has higher reliability to reflect the actual accessibility of survey region. Taking 123 of 3A scenic spots in Xinjiang as the research objects, this article analyzed the spatial distribution of the actual accessibility and compared the two algorithms from the perspective of accessibility. Results shows that new algorithm has higher reliability than traditional algorithm, and it has stronger correlation with the density of road networks than the traditional measurement. The patterns of spatial distribution of accessibility changed from symmetrical triangle to stair-step shape from southeast to northwest of Xinjiang.

References | Related Articles | Metrics

Evaluation Index System of Comprehensive Benefit for Afforestation Carbon Sequestration Projects in Arid Area

SHI Qing-dong, WU You-jun, ZHAO Fu-sheng, YI Huai-feng, ZHANG Xin-ping, CHANG Shun-li, ZHANG Yu-tao, ZHANG Wei-yan

2015, 32 (2): 368-375. doi: 10.13866/j.azr.2015.02.23

Abstract ( 637 )

PDF (1193KB) ( 1323 )

With the development of afforestation carbon sequestration project work in China, it seems important to have an evaluation system to assess the comprehensive benefits of carbon sequestration projects afforestation. Based on the specific natural geographic environment in arid areas, this study adopted a comprehensive index system method and selected representative indicators to establish an evaluation index system for afforestation carbon sequestration projects in arid areas according to the characteristics and the functions of the projects from the perspectives of ecology, sociology and economics. This assessment system is different from other evaluation systems by introducing a greenhouse gas emission target index. This paper discussed the differences of greenhouse gas emission index with the traditional solid carbon target index and presented the calculation methods of indicators. The results of the study provided useful support to the development and the management of afforestation carbon sequestration projects in arid areas.

References | Related Articles | Metrics

Evaluation Methods of Large-Scale Tree-Planting for CO₂ Emission Reduction in Arid Areas

YI Huai-feng, SHI Qing-dong, WU You-jun, ZHAO Fu-sheng, ZHANG Yu-tao, ZHANG Xin-ping, CHANG Shun-li, ZHANG Wei-yan

2015, 32 (2): 376-381. doi: 10.13866/j.azr.2015.02.24

Abstract ( 678 )

PDF (787KB) ( 966 )

It is a widely recognized one of the most cost-effective way to increase forest carbon sinks to control the rising of CO₂ concentration in atmosphere through afforestation and reforestation. Carbon sinks of artificial plantations are also recognized as a probable and likely way to mitigate global climate change. According to the national and international calculation rules of tree-planting CO₂ emission reduction, this study proposed a method to calculate the effect of the large-scale tree-planting CO₂ emission reduction through afforestation and reforestation based on the characteristics of the natural environment in arid areas. This paper discussed the ways how the calculation factors of the emission reduction were selected and suggested that a comprehensive research system should be put in place to reinforce the researches on forest carbon sinks from the perspectives of policy, technology and marketing, which could clearly and quantitively measure our country’s contribution to mitigate global climate changes through afforestation and reforestation in the arid areas. The results of the study provided useful support to the development and the management of afforestation carbon sequestration projects in arid areas.

References | Related Articles | Metrics

Emission Reductions of Greenhouse Gas of Afforestation Carbon Sequestration Projects in Karamay

ZHAO Fu-sheng, SHI Qing-dong, YI Huai-feng, WU You-jun, ZHANG Xin-ping, ZHANG Wei-yan

2015, 32 (2): 382-387. doi: 10.13866/j.azr.2015.02.25

Abstract ( 749 )

PDF (789KB) ( 852 )

According to the calculation methods of certified emission reductions under the clean development mechanism of Kyoto Protocol, this study investigated the greenhouse gas (GHG) emission reductions under afforestation and reforestation projects in Karamay. We set up 2 fixed-point plots and 48 random plots inside the artificial forest; one fixed-point plot and 4 random plots outside the artificial forestry under a desert environment. Carbon storages of the artificial forest and the desert were calculated as well as the GHG emission and leakage of the artificial forest. The net GHG emission of the projects was calculated accordingly. The results showed that the GHG emission reductions was 432 751.59 t of CO₂ from the afforestation and reforestation projects in Karamay since 2001 to 2009 with an average annual emission reduction of 54 093.95 t of CO₂ over the period. The effect of the emission reductions was significant from the projects which indicated that it was feasible to adopt the afforestation and reforestation projects to reduce GHG emission in arid areas. The results of the study provided fundamental information for the development and the management of the projects.

References | Related Articles | Metrics

Research on Carbon Sinks of Poplar Plantations in Karamay

SHI Qing-san, MEIKERE Abulitifu, ZHANG Yu-tao, CHANG Shun-li, YI Huai-feng, Zhao Fu-sheng, ZHANG Wei-yan

2015, 32 (2): 388-394. doi: 10.13866/j.azr.2015.02.26

Abstract ( 694 )

PDF (1270KB) ( 885 )

With the expanding of the plantations in recent years, artificial forestry plays a more and more important role in carbon budget of the terrestrial ecosystem in China. This study estimated biomasses, carbon stocks, carbon densities and carbon sinks of the poplar plantations and the desert shruberies in Karamay through field investigations. According to the data observed and the modelling analysis, the study came with the following conclusions: ① The average unit biomass of the poplar plantations was 51.30 t·hm^-2; mean carbon density was 24.59 t·hm^-2; the total carbon storage was 73 715.41 t, which demonstrated that poplar plantations played a certain role in carbon sequestration. ② Compare with under the desert shrubberies, biomass, mean carbon density and the total carbon storage of poplar plantations increased 50.56 t·hm^-2, 24.26 t·hm^-2 and 72 726.14 t, respectively. The results of the study indicated that afforestation can effectively increase the carbon sequestration of the terrestrial vegetation ecosystem in a desert environment in arid areas. It is a feasible way to achieve the carbon emission targets.

References | Related Articles | Metrics

Biomass Estimation of a Large-Scale Poplar Plantations in Desert Environment

WANG An-long, MEIKERE Abulitifu, SHI Qing-san, ZHAO Fu-sheng, ZHANG Xin-ping, ZHANG Yu-tao, PENG Jia-bin

2015, 32 (2): 395-401. doi: 10.13866/j.azr.2015.02.27

Abstract ( 706 )

PDF (1069KB) ( 776 )

Using dimensional analysis and all harvesting method, this study measured and analyzed the biomasses of the arbor layer, the understory vegetation layer and the litter layer in the poplar plantations in Karamay. The results showed that the tree organ biomasses of the arbor layer decreased as an order of trunk (60.79%)>root (14.27%)>branch (9.84%)>bark (8.96%)>leave (6.14%). The biomass of the arbor vegetation with 6-12 cm diameter breast height (DBH) accounted for 61.78% of the arbor vegetation biomass. It was a better choice to adopt 8 m×0.75 m and 4.5 m×2 m single groove single plant models in this area. Populus alba var. pyramidalis was more suitable than than Populus russkii under the same tree-planting patterns in the poplar plantations. The mean biomasses of the arbor layer, the understory vegetation layer and the litter layer were 45.285 t·hm^-2, 1.753 t·hm^-2 and 4.171 t·hm^-2, respectively. The research provided theoretical and practical guidance for the implementation of the large-scale poplar plantations in desert environment.

References | Related Articles | Metrics

Biomass and Soil Physical-Chemical Properties of Poplar Plantations in Karamay

ZHANG Yu-tao, GUO Shu-fang, ZHANG Xin-ping, SHI Qing-dong, ZHAO Fu-sheng, CHANG Shun-li, PENG Jia-bin

2015, 32 (2): 402-409. doi: 10.13866/j.azr.2015.02.28

Abstract ( 862 )

PDF (909KB) ( 864 )

This study investigated the biomasses and the soil physical-chemical properties of the poplar plantations and the desert shrubbery communities around the artificial forest in Karamay. The study came with the following conclusions. First, the biomass of the understory vegetation layer and the litter layer of the poplar plantations was 5.87 t·hm^-2; the biomass of the desert shrubby communities around the plantations was 0.74 t·hm^-2. The biomass of the plantations was significantly higher than the biomass of the desert shrubbery communities around the plantations. Second, soil nutrients in the different soil layers within the plantations were lower than the biomass in the relative soil layers in the desert while the soil bulk density increased and the soil moisture significantly increased. Third, the soil organic matter of the plantation was lower than that of the desert. The topsoil of the plantation decreased 8.83% compared with the desert. However, the soil organic matters of the plantation at the soil depths of 10-30 cm and 30-50 cm increased 20.74% and 33.13% respectively compared with the desert. Fourth, within the plantations, there was a significant and positive correlation between organic matter of the litter and the soil moisture of each soil layers but no correlation between the soil organic matter and the soil nutrients.

References | Related Articles | Metrics

Impact of Afforestation on Increment of Transpiration of the Carbon Sink Forest in Western Junggar Basin, Xingjiang

ZHANG Xin-ping, LIANG Feng-chao, SHI Qing-dong, ZHAO Fu-sheng, ZHANG Yu-tao, PENG Jia-bin

2015, 32 (2): 410-416. doi: 10.13866/j.azr.2015.02.29

Abstract ( 643 )

PDF (1028KB) ( 1703 )

The study area was located in western Junggar Basin where the water resources are extremely scarcity. It is important to investigate and analyze the transpiration of the artificial forest before and after the afforestation. Through monitoring the sap flows of Populus russkii, Populus alba var.pyramidalis and Haloxylon ammodendron, we calculated the transpiration of the plantations within the artificial forest as well as the evapotranspiration of the Haloxylon forest around the plantations in the natural desert environment. Sapwood area was selected as the conversion scalar. The results showed that there was a significant difference in transpiration within the plantation from that outside the plantation. The water consumption from the transpiration within the plantation was 19 times of that of the Haloxylon forest around the plantation in Karamay.

References | Related Articles | Metrics

Table of Content