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| 1 | Impact of land use change on water resource allocation in the middle reaches of the Heihe River Basin in northwestern China显示文摘In recent decades, China has been experiencing rapid economic development, population growth and urbanization. These processes have stressed the shortages of water resources in China, especially in the arid re- gions of northwestern China. In order to sustain the expanding cropland, people increased groundwater exploitation in these regions. The purpose of this study was to quantitatively analyze the changes in land use and water re- sources, and their relationship in the middle reaches of the Heihe River Basin, a typical inland river basin in northwest China. The data of land use change were interpreted using aerial photographs(1965) and Landsat TM images(1986 and 2007). The data of irrigation water volume in the irrigation districts were spatialized in the middle reaches of the Heihe River Basin. The spatial variation of the groundwater depth was interpolated using the geo- statistical method. The results showed that the cultivated cropland area along oasis fringe increased by 15.38% and 43.60% during the periods 1965–1986 and 1986–2007, respectively. Surface water amount for irrigation had almost doubled from 1956 to 2010. The decrease of grassland area mainly occurred at the alluvial fan in front of the Qilian Mountains, with 36.47% during 1965–1986 and 38.56% during 1986–2007, respectively. The groundwater depth in front of the mountain constantly increased from 1986 to 2007. We found that the overuse of surface water and overexploitation of groundwater had direct consequences on the natural environments. We suggests that the efficiency of surface water resources use among different irrigation districts needs to be improved, which will sig- nificantly ease the conflicts between increasing water demand for irrigation and a shortage of water resources in the middle reaches of the Heihe River Basin. | YanYun NIAN Xin LI Jian ZHOU XiaoLi HU | 2014 | Journal of Arid Land2014，6，3： | 32 |
| 2 | Soil surface roughness change and its effect on runoff and erosion on the Loess Plateau of China显示文摘As an important parameter in the soil erosion model, soil surface roughness(SSR) is used to quantitatively describe the micro-relief on agricultural land. SSR has been extensively studied both experimentally and theoretically; however, no studies have focused on understanding SSR on the Loess Plateau of China. This study investigated changes in SSR for three different tillage practices on the Loess Plateau of China and the effects of SSR on runoff and erosion yield during simulated rainfall. The tillage practices used were zero tillage(ZT), shallow hoeing(SH) and contour ploughing(CP). Two rainfall intensities were applied, and three stages of water erosion processes(splash erosion(I), sheet erosion(II) and rill erosion(III)) were analyzed for each rainfall intensity. The chain method was used to measure changes in SSR both initially and after each stage of rainfall. A splash board was used to measure the splash erosion at stage I. Runoff and sediment data were collected continuously at 2-min intervals during rainfall erosion stages II and III. We found that SSR of the tilled surfaces ranged from 1.0% to 21.9% under the three tillage practices, and the order of the initial SSR for the three treatments was ZT0.49) for the ZT, SH and CP treatments. The runoff initiation time was longer in the SH and CP treatments than in the ZT treatment. There were no significant differences in the total runoff yields among the ZT, SH and CP treatments. Sediment loss was significantly smaller(P<0.05) in the SH and CP treatments than in the ZT treatment. | LongShan ZHAO XinLan LIANG FaQi WU | 2014 | Journal of Arid Land2014，6，4： | 30 |
| 3 | Effect of vegetation on soil water retention and storage in a semi-arid alpine forest catchment显示文摘The runoff generated from mountainous regions is recognized as the main water source for inland river basins in arid environments. Thus, the mechanisms by which catchments retain water in soils are to be understood. The water storage capacity of soil depends on its depth and capacity to retain water under gravitational drainage and evapotranspiration. The latter can be studied through soil water retention curve (SWRC), which is closely related to soil properties such as texture, bulk density, porosity, soil organic carbon content, and so on. The present study represented SWRCs using HYDRUS-1D. In the present study, we measured physical and hydraulic properties of soil samples collected from Sabina przewalskii forest (south-facing slope with highest solar radiation), shrubs (west-facing slope with medium radiation), and Picea crassifolia forest (north-facing slope with lowest radiation), and analyzed the differences in soil water storage capacity of these soil samples. Soil water content of those three vegetation covers were also measured to validate the soil water storage capacity and to analyze the relationship between soil organic matter content and soil water content. Statistical analysis showed that different vegetation covers could lead to different soil bulk densities and differences in soil water retention on the three slope aspects. Sand content, porosity, and organic carbon content of the P. crassifolia forest were relatively greater compared with those of the S. przewalskii forest and shrubs. However, silt content and soil bulk density were relatively smaller than those in the S. przewalskii forest and shrubs. In addition, there was a significant linear positive relationship between averaged soil water content and soil organic matter content (P<0.0001). However, this relationship is not significant in the P. crassifolia forest. As depicted in the SWRCs, the water storage capacity of the soil was 39.14% and 37.38% higher in the P. crassifolia forest than in the S. przewalskii forest and shrubs, respectively, at a similar soil depth. | Chao WANG ChuanYan ZHAO ZhongLin XU Yang WANG HuanHua PENG | 2013 | Journal of Arid Land2013，5，2： | 25 |
| 4 | Temporal and spatial variation of annual mean air temperature in arid and semiarid region in northwest China over a recent 46 year period显示文摘We analyzed the 1961-2006 mean surface air temperature data of 138 stations in China's northwest arid and semi-arid areas(CNASA),to measure climate change in terms of annual mean air temperature changes.We used methods of linear regression analysis,multinomial fitting,Empirical Or-thogonal Function(EOF),Rotated Empirical Orthogonal Function(REOF),Mann-Kendall,Glide T-examination,wavelet analysis and power spectrum analysis.The results show that(1) the warming rate of the annual mean air temperature in CNASA was 0.35oC/10a during the 1961-2006 study period.Some places in the west part of Xinjiang and east part of the Qinghai plateau,which is impacted by the terrain of leeward slope,exhibit smaller increasing trends.However,the majority of region has shown distinct warming in line with general global warming;(2) The standard deviation of the annual mean temperature distribution is non-uniform.The south Xinjiang and east Qinghai-south Gansu areas show relatively small standard deviations,but the inter-annual variation in annual mean air temperature in the greater part of the region is high;(3) Inner Mongolia,Shaanxi,Gansu,Ningxia and Tarim Basin are the areas where the temperature changes are most sensitive to the environment.The degree of uniformity in annual mean air temperature increase is higher in the arid and semi-arid area.From the early 1970s,the trend in tempera-ture changed from a decrease to an increase,and there was a marked increase in mean temperature in 1986.After that mean temperature went through a period of rapid increase.The entire area's 10 hottest years all occurred in or since the 1990s,and 90% of various sub-districts' hottest years also occurred after 1990.The process of temperature change appears to have a roughly 5-year and a 10-year cycle;(4) An-nual mean air temperature variation has regional differences.In Inner Mongolia-Xinjiang and Shaanxi-Gansu-Ningxia-Qinghai areas,the temperature variation in their northern areas was very different from that in their southern areas;(5) Using the REOF method we divided the region into 4 sub-regions:the Northern region,the Plateau region,the Southern Xinjiang region and the Eastern region.The region's annual mean air temperature transition has regional differences.The Plateau and Southern Xinjiang re-gions got warmer steadily without any obvious acceleration in the rate of warming.The Northern region's warming started about 5-years earlier than that of the low latitude Eastern region.The 'Startup region' of the Qinghai-Tibet Plateau,appears to undergo temperature changes 3 to 10 years earlier than the other regions,and exhibits inter-decadal variations 1 to 2 years ahead of the other regions. | Chen, ShaoYong Shi, YuanYuan Guo, YuZhen Zheng, YanXiang | 2010 | Journal of Arid Land2010，2，2： | 24 |
| 5 | Effects of grazing on carbon and nitrogen in plants and soils in a semiarid desert grassland,China显示文摘Grazing can modulate the feedback between vegetation and soil nutrient dynamics(carbon and nitrogen),altering the cycles of these elements in grassland ecosystems.For clarifying the impact of grazing on the C and N in plants and soils in the desert grassland of Ningxia,China,we examined the plant biomass,SOC(soil organic carbon),total soil N and stable isotope signatures of plants and soils from both the grazed and ungrazed sites.Significantly lower aboveground biomass,root biomass,litter biomass and vegetation coverage were found in the grazed site compared to the ungrazed site,with decreases of 42.0%,16.2%,59.4% and 30.0%,respectively.The effects of grazing on plant carbon,nitrogen,?15N and ?13C values were uniform among species.The levels of plant carbon and nitrogen in grasses were greater than those in the forbs(except for the carbon of Cynanchum komarovii and Euphorbia esula).Root 15 N and 13 C values increased with grazing,while the responses of root carbon and nitrogen to grazing showed no consistent patterns.Root 15 N and 13 C were increased by 79.0% and 22.4% in the grazed site compared to the ungrazed site,respectively.The values of SOC and total N were significantly lower in the grazed than in the ungrazed sites for all sampling depths(0–10 and 10–20 cm),and values of SOC and total N at the surface(0–10 cm) were lower than those in the deeper soils(10–20 cm).Soil ?15N values were not affected by grazing at any sampling depth,whereas soil ?13C values were significantly affected by grazing and increased by 19.3% and 8.6% in the soils at 0–10 and 10–20 cm,respectively.The soil ?13C values(–8.3‰ to –6.7‰) were higher than those for roots(–20.2‰ to –15.6‰) and plant tissues(–27.9‰ to –13.3‰).Our study suggests that grazing could greatly affect soil organic carbon and nitrogen in contrast to ungrazed grassland and that grazing appears to exert a negative effect on soil carbon and nitrogen in desert grassland. | Hui AN GuoQi LI | 2015 | Journal of Arid Land2015，7，3： | 24 |
| 6 | Vegetation cover change and the driving factors over northwest China显示文摘In this paper the spatio-temporal variation of vegetation cover in northwest China during the period of 1982-2006 and its driving factors were analyzed using GIMMS/NDVI data. The annual average NDVI was increased with a rate of 0.0005/a in northwest China and there was an obvious difference between regions. The trend line slopes of NDVI were higher than 0.0005 in the Tianshan Moutains and Altay Mountains of Xinjiang,the Qilian Mountains of Gansu and the eastern part of Qinghai,which indicated the vegetation cover was significantly increased in these areas. The trend line slopes of NDVI were lower than 0.0005 in the southern region of Qinghai,the border regions of Shaanxi and Ningxia,the parts of Gansu and Tarim Basin,Turpan and Tuoli in Xinjiang,which indicated the vegetation cover was declined in these areas. The NDVI of woodland,grassland and cultivated land had an ascending tendency during the study period. The study shows that the vegetation cover change was caused by both natural factors and human activities in northwest China. The natural vegetation change,such as forests was influenced by climate change,while human activities were the main reason to the change of planting vegetation. The changes of vegetation covers for different elevations,slopes and slope aspects were quite different. When the elevation is exceeded to 4,000 m,the NDVI increasing trend was very low;the NDVI at the slope of less than 25° was increased by the ecological construction;the variation of NDVI on sunny slope was stronger than that on shady slope. The temperature rose significantly in recent 25 years in northwest China by an average rate of 0.67oC/10a,and precipitation increased by an average rate of 8.15 mm/10a after 1986. There was positive correlation between vegetation cover and temperature and annual precipitation changes. Rising temperature increased the evaporation and drought of soils,which is not conducive to plant growth,and the irrigation in agricultural areas reduced the correlation between agricultural vegetation NDVI and precipitation. The improvement of agricultural production level and the projects of ecological construction are very important causes for the NDVI increase in northwest China,and the ecological effect of large-scale ecological construction projects has appeared. | ShengPei DAI Bo ZHANG HaiJun WANG YaMin WANG LingXia GUO XingMei WANG Dan LI | 2011 | Journal of Arid Land2011，3，1： | 22 |
| 7 | Responses of microbial activities and soil physical-chemical properties to the successional process of biological soil crusts in the Gurbantunggut Desert,Xinjiang显示文摘Biological soil crusts(BSCs) are capable of modifying nutrient availability to favor the establishment of biogeochemical cycles. Microbial activities serve as critical roles for both carbon and nutrient transformation in BSCs. However, little is known about microbial activities and physical-chemical properties of BSCs in the Gurbantunggut Desert, Xinjiang, China. In the present research, a sampling line with 1-m wide and 20-m long was set up in each of five typical interdune areas selected randomly in the Gurbantunggut Desert. Within each sampling line, samples of bare sand sheet, algal crusts, lichen crusts and moss crusts were randomly collected at the depth of 0–2 cm. Variations of microalgal biomass, microbial biomass, enzyme activities and soil physical-chemical properties in different succession of BSCs were analyzed. The relationships between microalgal biomass, microbial biomass, enzymatic activities and soil physical-chemical properties were explored by stepwise regression. Our results indicate that microalgal biomass, microbial biomass and most of enzyme activities increased as the BSCs developed and their highest values occurred in lichen or moss crusts. Except for total K, the contents of most soil nutrients(organic C, total N, total P, available N, available P and available K) were the lowest in the bare sand sheet and significantly increased with the BSCs development, reaching their highest values in moss crusts. However, pH values significantly decreased as the BSCs developed. Significant and positive correlations were observed between chlorophyll a and microbial biomass C. Total P and N were positively associated with chlorophyll a and microbial biomass C, whereas there was a significant and negative correlation between microbial biomass and available P. The growth of cyanobacteria and microorganism contributed C and N in the soil, which offered substrates for enzyme activities thus increasing enzyme activities. Probably, improvement in enzyme activities increased soil fertility and promoted the growth of cyanobacteria, eukaryotic algae and heterotrophic microorganism, with the accelerating succession of BSCs. The present research found that microalgal-microbial biomass and enzyme activities played important roles on the contents of nutrients in the successional stages of BSCs and helped us to understand developmental mechanism in the succession of BSCs. | BingChang ZHANG XiaoBing ZHOU YuanMing ZHANG | 2015 | Journal of Arid Land2015，7，1： | 23 |
| 8 | Saline dust storms and their ecological impacts in arid regions显示文摘In many arid and semiarid regions,saline playas represent a significant source of unconsoli-dated sediments available for aeolian transport,and severe saline dust storms occur frequently due to human disturbance.In this study,saline dust storms are reviewed systematically from the aspects of con-cept,general characteristics,conditions of occurrence,distribution and ecological impact.Our researches showed that saline dust storms are a kind of chemical dust storm originating in dry lake beds in arid and semiarid regions;large areas of unconsolidated saline playa sediments and frequent strong winds are the basic factors to saline dust storm occurrence;there are differentiation characteristics in deposition flux and chemical composition with wind-blown distance during saline dust storm diffusion;and saline dust storm diffusion to some extent increases glacier melt and results in soil salinization in arid regions.An under-standing of saline dust storms is important to guide disaster prevention and ecological rehabilitation. | Jilili Abuduwaili | 2010 | Journal of Arid Land2010，2，2： | 21 |
| 9 | Relationship between dew presence and Bassia dasyphylla plant growth显示文摘Dew has been recognized for its ecological significance and has also been identified as an additional source of water in arid zones.We used factorial control experiment,under dew presence in the field,to explore photosynthetic performance,water status and growth response of desert annual herbage.Bassia dasyphylla seedlings were grown in contrasting dew treatments (dew-absent and dew-present) and different watering regimes (normal and deficient).The effects of dew on the water status and photosynthetic performance of Bassia dasyphylla,grown in a desert area of the Hexi Corridor in Northwestern China,were evaluated.The results indicated the presence of dew significantly increased relative water content (RWC) of shoots and total biomass of plants in both water regimes,and enhanced the diurnal shoot water potential and stomatal conductance in the early morning,as well as photosynthetic rate,which reached its maximum only in the water-stressed regime.The presence of dew increased aboveground growth of plants and photosynthate accumulation in leaves,but decreased the root-to-shoot ratio in both water regimes.Dew may have an important role in improving plant water status and ameliorating the adverse effects of plants exposed to prolonged drought. | YanLi ZHUANG Sophia RATCLIFFE | 2012 | Journal of Arid Land2012，4，1： | 21 |
| 10 | Accumulation of soil organic carbon during natural restoration of desertified grassland in China's Horqin Sandy Land显示文摘China's Horqin Sandy Land,a formerly lush grassland,has experienced extensive desertification that caused considerable carbon(C) losses from the plant-soil system.Natural restoration through grazing exclusion is a widely suggested option to sequester C and to restore degraded land.In a desertified grassland,we investigated the C accumulation in the total and light fractions of the soil organic matter from 2005 to 2013 during natural restoration.To a depth of 20 cm,the light fraction organic carbon(LFOC) storage increased by 221 g C/m2(84%) and the total soil organic carbon(SOC) storage increased by 435 g C/m2(55%).The light fraction dry matter content represented a small proportion of the total soil mass(ranging from 0.74% in 2005 to 1.39% in 2013),but the proportion of total SOC storage accounted for by LFOC was remarkable(ranging from 33% to 40%).The C sequestration averaged 28 g C/(m2·a) for LFOC and 54 g C/(m2·a) for total SOC.The total SOC was strongly and significantly positively linearly related to the light fraction dry matter content and the proportions of fine sand and silt+clay.The light fraction organic matter played a major role in total SOC sequestration.Our results suggest that grazing exclusion can restore desertified grassland and has a high potential for sequestering SOC in the semiarid Horqin Sandy Land. | YuQiang LI XueYong ZHAO FengXia ZHANG Tala AWADA ShaoKun WANG HaLin ZHAO TongHui ZHANG YuLin LI | 2015 | Journal of Arid Land2015，7，3： | 21 |
| 11 | Modeling spatio-temporal distribution of soil moisture by deep learning-based cellular automata model显示文摘Soil moisture content (SMC) is a key hydrological parameter in agriculture,meteorology and climate change,and understanding of spatio-temporal distributions of SMC in farmlands is important to address the precise irrigation scheduling.However,the hybrid interaction of static and dynamic environmental parameters makes it particularly difficult to accurately and reliably model the distribution of SMC.At present,deep learning wins numerous contests in machine learning and hence deep belief network (DBN) ,a breakthrough in deep learning is trained to extract the transition functions for the simulation of the cell state changes.In this study,we used a novel macroscopic cellular automata (MCA) model by combining DBN to predict the SMC over an irrigated corn field (an area of 22 km^2) in the Zhangye oasis,Northwest China.Static and dynamic environmental variables were prepared with regard to the complex hydrological processes.The widely used neural network,multi-layer perceptron (MLP) ,was utilized for comparison to DBN.The hybrid models (MLP-MCA and DBN-MCA) were calibrated and validated on SMC data within four months,i.e.June to September 2012,which were automatically observed by a wireless sensor network (WSN) .Compared with MLP-MCA,the DBN-MCA model led to a decrease in root mean squared error (RMSE) by 18%.Thus,the differences of prediction errors increased due to the propagating errors of variables,difficulties of knowing soil properties and recording irrigation amount in practice.The sequential Gaussian simulation (s Gs) was performed to assess the uncertainty of soil moisture estimations.Calculated with a threshold of SMC for each grid cell,the local uncertainty of simulated results in the post processing suggested that the probability of SMC less than 25% will be difference in different areas at different time periods.The current results showed that the DBN-MCA model performs better than the MLP-MCA model,and the DBN-MCA model provides a powerful tool for predicting SMC in highly non-linear forms.Moreover,because modeling soil moisture by using environmental variables is gaining increasing popularity,DBN techniques could contribute a lot to enhancing the calibration of MCA-based SMC estimations and hence provide an alternative approach for SMC monitoring in irrigation systems on the basis of canals. | SONG Xiaodong ZHANG Ganlin LIU Feng LI Decheng ZHAO Yuguo YANG Jinling | 2016 | Journal of Arid Land2016，8，5： | 20 |
| 12 | Soil salt leaching under different irrigation regimes: HYDRUS-1D modelling and analysis显示文摘Field irrigation experiments were conducted in the Hetao Irrigation District of Inner Mongolia,China,to study the effects of irrigation regimes on salt leaching in the soil profile.The data were used to calibrate and validate the HYDRUS-1D model.The results demonstrated that the model can accurately simulate the water and salt dynamics in the soil profile.The HYDRUS-1D model was then used to simulate 15 distinct irrigation scenarios.The results of the simulation indicated that irrigation amount did not have a significant effect on soil water storage but that increases in irrigation amount could accelerate salt leaching.However,when the irrigation amount was larger than 20 cm,the acceleration was not obvious.Compared with irrigating only once,intermittent irrigation had a better effect on increasing soil water storage and salt leaching,but excessive irrigation times and intervals did not improve salt leaching.In addition,we found that the irrigation regime of 20 cm,irrigated twice at 1-d intervals,might significantly increase salt leaching in the plough layer and decrease the risks of deep seepage and groundwater contamination. | WenZhi ZENG Chi XU JingWei WU JieSheng HUANG | 2014 | Journal of Arid Land2014，6，1： | 20 |
| 13 | Climate change, water resources and sustainable development in the arid and semi-arid lands of Central Asia in the past 30 years显示文摘The countries of Central Asia are collectively known as the five '-stans': Uzbekistan, Kyrgyzstan, Turkmenistan, Tajikistan and Kazakhstan. In recent times, the Central Asian region has been affected by the shrinkage of the Aral Sea, widespread desertification, soil salinization, biodiversity loss, frequent sand storms, and many other ecological disasters. This paper is a review article based upon the collection, identification and collation of previous studies of environmental changes and regional developments in Central Asia in the past 30 years. Most recent studies have reached a consensus that the temperature rise in Central Asia is occurring faster than the global average. This warming trend will not only result in a higher evaporation in the basin oases, but also to a significant retreat of glaciers in the mountainous areas. Water is the key to sustainable development in the arid and semi-arid regions in Central Asia. The uneven distribution, over consumption, and pollution of water resources in Central Asia have caused severe water supply problems, which have been affecting regional harmony and development for the past 30 years. The widespread and significant land use changes in the 1990 s could be used to improve our understanding of natural variability and human interaction in the region. There has been a positive trend of trans-border cooperation among the Central Asian countries in recent years. International attention has grown and research projects have been initiated to provide water and ecosystem protection in Central Asia. However, the agreements that have been reached might not be able to deliver practical action in time to prevent severe ecological disasters. Water management should be based on hydrographic borders and ministries should be able to make timely decisions without political intervention. Fully integrated management of water resources, land use and industrial development is essential in Central Asia. The ecological crisis should provide sufficient motivation to reach a consensus on unified water management throughout the region. | YU Yang PI Yuanyue YU Xiang TA Zhijie SUN Lingxiao Markus DISSE ZENG Fanjiang LI Yaoming CHEN Xi YU Ruide | 2019 | Journal of Arid Land2019，11，1： | 20 |
| 14 | Combined effects of snow depth and nitrogen addition on ephemeral growth at the southern edge of the Gurbantunggut Desert,China显示文摘Water and nitrogen(N) inputs are considered as the two main limiting factors affecting plant growth.Changes in these inputs are expected to alter the structure and composition of the plant community,thereby influencing biodiversity and ecosystem function.Snowfall is a form of precipitation in winter,and snow melting can recharge soil water and result in a flourish of ephemerals during springtime in the Gurbantunggut Desert,ChinaA bi-factor experiment was designed and deployed during the snow-covering season from 2009 to 2010.The experiment aimed to explore the effects of different snow-covering depths and N addition levels on ephemerals.Findings indicated that deeper snow cover led to the increases in water content in topsoil as well as density and coverage of ephemeral plants in the same N treatment;by contrast,N addition sharply decreased the density of ephemerals in the same snow treatment.Meanwhile,N addition exhibited a different effect on the growth of ephemeral plants:in the 50% snow treatment,N addition limited the growth of ephemeral plants,showing that the height and the aboveground biomass of the ephemeral plants were lower than in those without N addition;while with the increases in snow depth(100% and 150% snow treatments),N addition benefited the growth of the dominant individual plants.Species richness was not significantly affected by snow in the same N treatment.However,N addition significantly decreased the species richness in the same snow-covering depth.The primary productivity of ephemerals in the N addition increased with the increase of snow depth.These variations indicated that the effect of N on the growth of ephemerals was restricted by water supply.With plenty of water(100% and 150% snow treatments),N addition contributed to the growth of ephemeral plants;while with less water(50% snow treatment),N addition restricted the growth of ephemeral plants. | LianLian FAN Yan LI LiSong TANG Jian MA | 2013 | Journal of Arid Land2013，5，4： | 19 |
| 15 | Estimating aboveground biomass in Mu Us Sandy Land using Landsat spectral derived vegetation indices over the past 30 years显示文摘Remote sensing is a valuable and effective tool for monitoring and estimating aboveground biomass(AGB) in large areas.The current international research on biomass estimation by remote sensing technique mainly focused on forests,grasslands and crops,with relatively few applications for desert ecosystems.In this paper,Landsat Thematic Mapper(TM)/Enhanced Thematic Mapper Plus(ETM+) images from 1988 to 2007 and the data of 283 AGB samples in August 2007 were used to estimate the AGB for Mu Us Sandy Land over the past 30 years.Moreover,temporal and spatial distribution characteristics of AGB and influencing factors of climate and underlying surface were also studied.Results show that:(1) Differences of correlations exist in the fitted equations between AGB and different vegetation indices in desert areas.The modified soil adjusted vegetation index(MSAVI) and soil adjusted vegetation index(SAVI) show relatively higher correlations with AGB,while the correlation between normalized difference vegetation index(NDVI) and AGB is relatively lower.Error testing shows that the AGB-MSAVI model established can be used to accurately estimate AGB of Mu Us Sandy Land in August.(2) AGB in Mu Us Sandy Land shows the fluctuant characteristics over the past 30 years,which decreased from the 1980s to the 1990s,and increased from the 1990s to 2007.AGB in 2007 had the highest value,with a total AGB of 3.352×106 t.Moreover,in the 1990s,AGB had the lowest value with a total AGB of 2.328×106 t.(3) AGB with relatively higher values was mainly located in the middle and southern parts of Mu Us Sandy Land in the 1980s.AGB was low in the whole area in the1990s,and relatively higher AGB values were mainly located in the southern parts of Uxin.In 2007,AGB in the whole area was relatively higher than those of the last twenty years,and higher AGB values were mainly located in the northern,western and middle parts of Mu Us Sandy Land. | Feng YAN Bo WU YanJiao WANG | 2013 | Journal of Arid Land2013，5，4： | 19 |
| 16 | Impact of livelihood diversification of rural households on their ecological footprint in agro-pastoral areas of northern China显示文摘Human-environment relationship is a focus of academic researches and an understanding of the relationship is important for making effective policies and decisions. In this study, based on rural household survey data of Taibus Banner, Duolun county and Zhengxiangbai Banner in the Inner Mongolia autonomous region of China, we identified the impact of livelihood diversification on ecosystems in these agro-pastoral areas by using the ecological footprint theory and methodology together with the one-way analysis of variance(ANOVA) and correlation analysis methods. In 2011, the total ecological footprint of consumption(EFC) was 0.665 g hm2, and the total ecological footprint of production(EFP) was 2.045 g hm2, which was more than three times the EFC. The ecological footprint of arable land consumption(EFAC) accounted for a large proportion of the EFC, and the ecological footprint of grassland production(EFGP) occupied a large proportion of the EFP. Both the ecological footprint of grassland consumption(EFGC) and EFGP had a significant positive correlation with the income, indicating that income was mainly depended on livestock production and the households with higher incomes consumed more livestock products. The full-time farming households(FTFHs) had the highest EFP, ecological footprint of arable land production(EFAP), EFGP and EFGC, followed by the part-time farming households(PTFHs) and non-farming households(NFHs), which indicated that part-time farming and non-farming employment reduced the occupancy and consumption of rural households on local ecosystems and natural resources to some extent. When farming households engaged in livestock rearing, both the EFAP and EFAC became smaller, while the EFP, EFC, EFGC and EFGP increased significantly. The differences in ecological footprints among different household groups should be taken into account when making ecosystem conservation policies. Encouraging the laborers who have the advantages of participating in non-farming employment to move out of the rural areas and increasing the diversification of livelihoods of rural households are important in reducing the environmental pressures and improving the welfare of households in the study area. Moreover, grassland should be utilized more effectively in the future. | HAO Haiguang ZHANG Jiping LI Xiubin ZHANG Huiyuan ZHANG Qiang | 2015 | Journal of Arid Land2015，7，5： | 19 |
| 17 | Interactive effects of wind speed,vegetation coverage and soil moisture in controlling wind erosion in a temperate desert steppe,Inner Mongolia of China显示文摘The rapid desertification of grasslands in Inner Mongolia of China poses a significant ecological threaten to northern China. The combined effects of anthropogenic disturbances(e.g., overgrazing) and biophysical processes(e.g., soil erosion) have led to vegetation degradation and the consequent acceleration of regional desertification. Thus, mitigating the accelerated wind erosion, a cause and effect of grassland desertification, is critical for the sustainable management of grasslands. Here, a combination of mobile wind tunnel experiments and wind erosion model was used to explore the effects of different levels of vegetation coverage, soil moisture and wind speed on wind erosion at different positions of a slope inside an enclosed desert steppe in the Xilamuren grassland of Inner Mongolia. The results indicated a significant spatial difference in wind erosion intensities depending on the vegetation coverage, with a strong decreasing trend from the top to the base of the slope. Increasing vegetation coverage resulted in a rapid decrease in wind erosion as explained by a power function correlation. Vegetation coverage was found to be a dominant control on wind erosion by increasing the surface roughness and by lowering the threshold wind velocity for erosion. The critical vegetation coverage required for effectively controlling wind erosion was found to be higher than 60%. Further, the wind erosion rates were negatively correlated with surface soil moisture and the mass flux in aeolian sand transport increased with increasing wind speed. We developed a mathematical model of wind erosion based on the results of an orthogonal array design. The results from the model simulation indicated that the standardized regression coefficients of the main effects of the three factors(vegetation coverage, soil moisture and wind speed) on the mass flux in aeolian sand transport were in the following order: wind speed>vegetation coverage>soil moisture. These three factors had different levels of interactive effects on the mass flux in aeolian sand transport. Our results will improve the understanding of the interactive effects of wind speed, vegetation coverage and soil moisture in controlling wind erosion in desert steppes, and will be helpful for the design of desertification control programs in future. | MENG Zhongju DANG Xiaohong GAO Yong REN Xiaomeng DING Yanlong WANG Meng | 2018 | Journal of Arid Land2018，10，4： | 19 |
| 18 | Volume fractal dimension of soil particles and relationships with soil physical-chemical properties and plant species diversity in an alpine grassland under different disturbance degrees显示文摘Fractal geometry is an important method in soil science,and many studies have used fractal theory to examine soil properties and the relationships with other eco-environmental factors.However,there have been few studies examining soil particle volume fractal dimension in alpine grasslands.To study the volume fractal dimension of soil particles(D) and its relationships with soil salt,soil nutrient and plant species diversity,we conducted an experiment on an alpine grassland under different disturbance degrees:non-disturbance(N 0),light disturbance(L),moderate disturbance(M) and heavy disturbance(H).The results showed that(1) Ds varied from 2.573 to 2.635 among the different disturbance degrees and increased with increasing degrees of disturbance.(2) Shannon-Wiener diversity index,Pielou's evenness index and Margalef richness index reached their highest values at the M degree,indicating that moderate disturbance is beneficial to the increase of plant species diversity.(3) In the L and M degrees,there was a significant positive correlation between D and clay content and a significant negative correlation between D and soil organic matter(SOM).In the H degree,D was significantly and positively correlated with total salt(TS).The results suggested that to a certain extent,D can be used to characterize the uniformity of soil texture in addition to soil fertility characteristics.(4) For the L degree,there was a significant negative correlation between D and the Shannon-Wiener diversity index;while for the M degree,there was a significant negative correlation between D and Pielou's evenness index. | YanYan LIU YanMing GONG Xin WANG YuKun HU | 2013 | Journal of Arid Land2013，5，4： | 18 |
| 19 | Leaf N and P stoichiometry of 57 plant species in the Karamori Mountain Ungulate Nature Reserve,Xinjiang,China显示文摘Nitrogen(N) and phosphorus(P) are the major nutrients that constrain plant growth and development,as well as the structure and function of ecosystems.Hence,leaf N and P patterns can contribute to a deep understanding of plant nutrient status,nutrient limitation type of ecosystems,plant life-history strategy and differentiation of functional groups.However,the status and pattern of leaf N and P stoichiometry in N-deficiency desert ecosystems remain unclear.Under this context,the leaf samples from 57 plant species in the Karamori Mountain Ungulate Nature Reserve,eastern Junggar Desert,China were investigated and the patterns and interrelations of leaf N and P were comparatively analyzed.The results showed that the average leaf N concentration,P concentration,and N:P ratio were 30.81 mg/g,1.77 mg/g and 17.72,respectively.This study found that the leaf N concentration and N:P ratio were significantly higher than those of studies conducted at global,national and regional scales;however,the leaf P concentration was at moderate level.Leaf N concentration was allometrically correlated with leaf P and N:P ratio across all species.Leaf N,P concentrations and N:P ratio differed to a certain extent among plant functional groups.C_4 plants and shrubs,particularly shrubs with assimilative branches,showed an obviously lower P concentration than those of C_3 plants,herbs and shrubs without assimilative branches.Shrubs with assimilative branches also had lower N concentration.Fabaceae plants had the highest leaf N,P concentrations(as well as Asteraceae) and N:P ratio;other families had a similar N,P-stoichiometry.The soil in this study was characterized by a lack of N(total N:P ratio was 0.605),but had high N availability compared with P(i.e.the available N:P ratio was 1.86).This might explain why plant leaves had high N concentration(leaf N:P ratio>16).In conclusion,the desert plants in the extreme environment in this study have formed their intrinsic and special stoichiometric characteristics in relation to their life-history strategy. | TAO Ye WU Ganlin ZHANG Yuanming ZHOU Xiaobing | 2016 | Journal of Arid Land2016，8，6： | 18 |
| 20 | Impact of nitrogen addition on plant community in a semi-arid temperate steppe in China显示文摘Increased nitrogen (N) deposition will often lead to a decline in species richness in grassland ecosystems but the shifts in functional groups and plant traits are still poorly understood in China.A field experiment was conducted at Duolun,Inner Mongolia,China,to investigate the effects of N addition on a temperate steppe ecosystem.Six N levels (0,3,6,12,24,and 48 g N/(m 2 a)) were added as three applications per year from 2005 to 2010.Enhanced N deposition,even as little as 3 g N/(m 2 a) above ambient N deposition (1.2 g N/(m 2 a)),led to a decline in species richness of the whole community.Increasing N addition can significantly stimulate aboveground biomass of perennial bunchgrasses (PB) but decrease perennial forbs (PF),and induce a slight change in the biomass of shrubs and semi-shrubs (SS).The biomass of annuals (AS) and perennial rhizome grasses (PR) accounts for only a small part of the total biomass.Species richness of PF decreased significantly with increasing N addition rate but there was a little change in the other functional groups.PB,as the dominant functional group,has a relatively higher height than others.Differences in the response of each functional group to N addition have site-specific and species-specific characteristics.We initially infer that N enrichment stimulated the growth of PB,which further suppressed the growth of other functional groups. | Ling SONG XueMei BAO XueJun LIU FuSuo ZHANG | 2012 | Journal of Arid Land2012，4，1： | 18 |
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