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Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

What represents a water source for the ecological restoration of a plant in an arid region is still up to debate. To address this issue, we conducted an in situ experiment in the Ulan Buh Desert of China, to study desert plants absorbing atmospheric water vapor. We selected Tamarisk, a common drought-salt-tolerant species in the desert, for ecological restoration as our research subject, used a newly designed lysimeter to monitor precipitation infiltration, and a sap flow system to track reverse sap flow that occurred in the shoot, branch, and stem during the precipitation event, and observed the precipitation redistribution process of the Tamarisk plot. The results showed that Tamarisk indeed directly absorbs precipitation water: when precipitation occurs, the main stem, lateral branch, and shoot all show the signs of reversed sap flow, and the reversed sap flow accounted for 21.5% of the annual sap flow in the shoot and branch, and 13.6% in the stem. The precipitation event in the desert was dominated by light precipitation events, which accounted for 81% of the annual precipitation events. It was found that light precipitation can be directly absorbed by the Tamarisk leaves, especially during nighttime or cloudy days. Even when the precipitation is absent, it was found that desert plants can still absorb water from the unsaturated atmospheric vapor; even the absorbed atmospheric water vapor was transported from the leaves to the stem, forming a reversed sap flow, as a reversed sap flow was observed when the atmospheric relative humidity reached 75%. This study indicated that the effect of light precipitation on desert plants was significant and should not be overlooked in terms of managing the ecological and hydrological systems in arid regions. [ABSTRACT FROM AUTHOR]

Nebkhas can be one of the most widespread biogenic landform types in the transition zone of a desert oasis. Desertification can be further prevented to improve the ecological functions for the soil fertility and sustainable development of oasis areas. The existing research focused mainly on the morphological, physicochemical and surface erosion of nebkhas. It is still lacking on the windbreak effects of nebkhas at different evolution stages and vegetation coverages, particularly from the perspective of wind speed field. This study aims to investigate the distribution of wind speed and windbreak effect of nebkhas under different evolution stages and vegetation coverages, in order to control the soil wind erosion. A single and two Nitraria tangutorum nebkhas in Ulan Buh desert-oasis ecotone were selected as the research objects. The wind speed distributions in vertical and horizontal planes of nebkhas were measured at four evolution stages (embryonic, developing, stable and activating stage), and three vegetation coverages (0, 40%, and 70%) using wind tunnel simulation tests. A systematic investigation was implemented to explore the effects of the evolution stage and vegetation coverage on the windbreak indicators, including the relative wind speed and windbreak efficiency. It was found that there was quite a similar variation in the wind speed around nebkhas at the initial wind speeds of 6, 8, and 10 m/s. The wind speed varied significantly in the range of 0-0.8H (H was the height of Nitraria tangutorum nebkhas) in the vertical direction and –H-5H from the center of nebkhas in the horizontal direction. The wind speed gradually recovered to the corresponding value without the place of nebkhas above the height of 1.2H. A comparison was made on the wind speed variations in the upstream deceleration zone, upper acceleration zone, bilateral jet stream area and leeward deceleration zone. It was found that all nebkhas in the leeward deceleration zone shown the most significant variation in the wind speed at different evolution stages. The maximum reduction of wind speed reached 90% for Nitraria tangutorum nebkhas at the stable stage with a vegetation coverage of 70%. Additionally, the experimental results show that both the evolution stage and vegetation coverage of nebkhas posed great effects on the wind speed distribution around the nebkhas and the windbreak efficiency. Specifically, there was a more significant reduction in the wind speed of Nitraria tangutorum nebkhas at the stable stage, indicating greater windbreak efficiency. However, a relatively weak reduction was observed in the nebkhas at an embryonic stage. The interaction was also considered on two nebkhas that were arranged in parallel to the wind direction. The more significant windbreak efficiency was found in the lowland between two nebkhasis, compared with a single one. And the windbreak efficiency of the second nebkha in the downstream region was slightly smaller than that of the lowland area between the two nebkhas. All nebkhas at different evolution stages show that the windbreak efficiencies around a single and two nebkhas increased with the increase of vegetation coverage. The finding can provide a theoretical basis for decision-making on the measures to control the soil wind erosion in the Ulan Buh desert-oasis ecotone. [ABSTRACT FROM AUTHOR]

[Objective] Studying the windbreak and sand fixation effects of highway protection systems can provide scientific basis for the prevention and control of sand damage on regional highways. [Methods] The protection system of the Deng-E Desert Highway in the northeast of Ulanbuhe Desert was taken as the research object, and synchronous observation was conducted on the sediment discharge and wind speed of the protective system. [Results](1) After the sand flow passes through the protection system, the wind speed and total sand transport at each height decrease, and the surface roughness increases. The wind speed in the upwind direction(point B) and downwind direction(point C) of the protection system decreases by 48.7%, 14.4%, and 3.9%, respectively, compared to point A from high to low. The total sand transport rate decreased by 86.4% and 98.3%, respectively, compared to point A, and the surface roughness increases from about 0 cm to 4.92 cm.(2) The vertical distribution of sand particle size shows a significant decrease in medium sand content and a significant increase in fine sand content. The particle size distribution of surface sediment decreases, the frequency distribution curve narrows in some bands, and the sorting ability deteriorates. The particle distribution is uniform and develops towards fine-grained direction, with a range of easily weathered particles ranging from 180 to 200 μm. [Conclusion] For road sand prevention projects, there should be a construction concept of “putting resistance first and combining resistance and fixation”. At the same time, the practice of road wind and sand prevention and fixation systems in this research area can provide important reference experience for road sand prevention in the other regions. [ABSTRACT FROM AUTHOR]

Many rivers are tightly coupled and intersected with aeolian sand dunes, whose geomorphological evolution involves not only fluvial processes but also aeolian processes that pose a new challenge to fluvial geomorphological studies. However, due to few field studies, our overall understanding of the desert channel geomorphic process is limited. In this paper, we present an outstanding example of desert river channel evolution regulated by aeolian–fluvial interactions in the Ulan Buh Desert of the Yellow River, based on a long time series data set (1966–2019) of channel cross-sections. The results indicate that the lateral addition of aeolian sand, the water–sediment relationship and human interference have a significant role at different periods of channel evolution. Before 1986, higher discharge, lower sediment content and greater intensity of aeolian activity caused aeolian–fluvial interactions and a relative scouring and silting balance in the channel, with little human activity. From 1986 to 2000, an increase in large reservoir operation, vegetation coverage and floodplain farming, coupled with water–sediment relationship variation, caused rapid deposition and shrinkage of the river channel. From 2000 to 2014, the channel kept a slight scouring state. With Haibowan reservoir operation beginning in 2014, the talweg experienced rapid scouring and undercut rebound. However, an expanding and stable floodplain accelerated sedimentation on the floodplain and weakened river lateral erosion, indicating that the channel has shown a shrinkage trend. Meanwhile, wavelet analysis results indicate that human interferences and aeolian activities have no significant role in the periodical characteristics of the channel's longitudinal erosion and deposition. Therefore, on the whole, increasing human interferences and decreasing wind dynamics have driven this desert wandering channel to be stable, and to gradually form a new balance between erosion and sedimentation. [ABSTRACT FROM AUTHOR]

The river flowing across the desert are controlled by the aeolian–fluvial interaction, with frequently scouring and depositing, which threaten the river banks safety. The floodplains are the main sediment sink, where aeolian sands and fluvial sediments are interacted. Exploring the characteristics and mechanism of selective deposition in the floodplain can provide insight into the influence mechanism of aeolian–fluvial interaction on desert river geomorphological process. Based on the sediment drilling data, this paper discusses the process and law of the selective deposition in the floodplain through the multi-dimensional analysis of the sediment grain-size in this desert reach of the Yellow River. The results show that the sedimentary structure of the river floodplain and bar shows a coarse and fine binary sedimentary interbedded under the control of the two origin components of aeolian and fluvial sediments, without forming a typical binary sedimentary structure. The median grain-size of the finer sediment layers is about 0.06 mm, which is comparable to that of upstream fluvial sediments. In addition, the median size of coarse sediment layers is about 0.19mm, which is consistent with the aeolian sand of the left bank. Meanwhile, the farther away from the desert dunes, the closer to the main channel, the characteristics of the interbedded river floodplain sedimentation gradually weaken, and binary sedimentary structure of floodplain gradually strengthened, which indicate the weakening of the coupling interactions between aeolian process and fluvial process and the gradual redution in the lateral infusion of the aeolian sand into the Yellow River, and the river channel are gradually stabilizing. [ABSTRACT FROM AUTHOR]

Desert farmland provides food for desert areas, but water is the main limiting factor of this region, thus desert farmland has an extremely fragile ecological environment. This study investigated the temporal and spatial variations of vegetation NDVI (Normalized Difference Vegetation Index) in the Ulan Buh Desert, China, from 1990 to 2022, using long-term Landsat satellite data obtained from the Google Earth Engine platform and local statistical data. The results showed that from 1990 to 2022, the NDVI exhibited relatively small fluctuations and a steady increase. Furthermore, the study analyzed the impact of climate factors, namely precipitation and temperature, on NDVI, and collected the groundwater lever changes under irrigation and farmland development. The results demonstrated a positive correlation between NDVI and both precipitation and temperature from 1990 to 2006. The study area experienced an overall trend of increasing humidity. Specifically, from 1990 to 2006, significant positive correlations with precipitation and temperature were observed in 4.4% and 5.5% of the region, respectively. From 2007 to 2022, significant positive correlations were observed in 5.4% and 72.8% of the region for precipitation and temperature, respectively. These findings suggest that temperature has become increasingly influential on vegetation NDVI, while the impact of precipitation remains relatively stable. Moreover, the study assessed the impact of human activities on vegetation NDVI. The results revealed that from 1990 to 2006, human activities contributed to 43.1% of the promotion of local vegetation NDVI, which increased to 90.9% from 2007 to 2022. This study provides valuable insights into the dynamics of vegetation in the Ulan Buh Desert and its response to climatic changes and human activities. The findings highlight the significance of climate conditions and human interventions in shaping the vegetation dynamics in the region, offering essential information for ecological restoration and conservation efforts. [ABSTRACT FROM AUTHOR]

Desertification is a primary threat to crop farming, the livestock industry, and the eco-environment in northwestern China. Through field research and satellite imagery, it has been discovered that there are 4–5 sand belts in the shape of handclasps connecting major deserts in the Alxa Plateau region of northern China. These sand belts have been expanding for several decades. However, eolian sand transport between major deserts through these expanding sand belts is still underestimated. Identifying the source areas of eolian sands in deserts provide essential knowledge to prevent desertification. In this study, we collected samples from the northern Ulan Buh Desert (UBD), the Yamalik Desert (YD), and the Langshan Mountains and analyzed their REE contents in the

As a typical desert in the Inner Mongolia Autonomous Region, the Ulan Buh Desert has a dry climate and scarce precipitation all year round. Groundwater has become the main factor limiting the growth of vegetation in this region. It is of great significance to study the influence of groundwater depth on the spatial distribution pattern of vegetation in this region. Based on the PIE-Engine platform and using long-term time-series Landsat data, this paper analyzed the spatial–temporal distribution characteristics and trends in vegetation coverage in the Ulan Buh Desert in the last 20 years using a pixel dichotomy model and the image difference method. The Kriging interpolation method was used to interpolate the groundwater depth data from 106 monitoring wells in the Ulan Buh Desert over the past 20 years, and the spatial distribution characteristics of groundwater depth in the Ulan Buh Desert were analyzed. Finally, the correlation coefficient between changes in vegetation coverage and changes in groundwater depth was calculated. The results showed the following: (1) The vegetation coverage in the Ulan Buh Desert was higher in the periphery and lower in the center of the desert. The overall vegetation level showed an increasing trend year by year; the growth rate was 4.73%/10 years, and the overall vegetation cover showed an improving trend. (2) The overall groundwater depth in the Ulan Buh Desert was deep in the southwest and shallow in the northeast. In the past 20 years, the groundwater depth in the Ulan Buh area has become shallower, and the ecological condition has gradually improved. (3) On the whole, the vegetation coverage varied with the groundwater depth, and the shallower the groundwater depth, the greater the vegetation coverage. When the groundwater depth increased to more than 4 m, the change in the groundwater depth had a significant effect on the vegetation coverage. However, when the groundwater depth was greater than 6 m, the change in the groundwater depth had no significant effect on the change in vegetation coverage. [ABSTRACT FROM AUTHOR]

What represents a water source for the ecological restoration of a plant in an arid region is still up to debate. To address this issue, we conducted an in situ experiment in the Ulan Buh Desert of China, to study desert plants absorbing atmospheric water vapor. We selected Tamarisk, a common drought-salt-tolerant species in the desert, for ecological restoration as our research subject, used a newly designed lysimeter to monitor precipitation infiltration, and a sap flow system to track reverse sap flow that occurred in the shoot, branch, and stem during the precipitation event, and observed the precipitation redistribution process of the Tamarisk plot. The results showed that Tamarisk indeed directly absorbs precipitation water: when precipitation occurs, the main stem, lateral branch, and shoot all show the signs of reversed sap flow, and the reversed sap flow accounted for 21.5% of the annual sap flow in the shoot and branch, and 13.6% in the stem. The precipitation event in the desert was dominated by light precipitation events, which accounted for 81% of the annual precipitation events. It was found that light precipitation can be directly absorbed by the Tamarisk leaves, especially during nighttime or cloudy days. Even when the precipitation is absent, it was found that desert plants can still absorb water from the unsaturated atmospheric vapor; even the absorbed atmospheric water vapor was transported from the leaves to the stem, forming a reversed sap flow, as a reversed sap flow was observed when the atmospheric relative humidity reached 75%. This study indicated that the effect of light precipitation on desert plants was significant and should not be overlooked in terms of managing the ecological and hydrological systems in arid regions.

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Most of the sand fixation technologies utilized locally and internationally are static or dynamic, making it challenging for a single sand fixation mode to function in a harsh environment. Therefore, the development of a sand fixation mode that combines resistance and consolidation has emerged as a trending topic in sand control research. Our team developed the wing bag sand barrier, which is a static and dynamic combination of sand fixation mode.Methods: In this study, we examined the characteristics of airflow velocity field and sand resistance near double-row wing bag sand barrier under different wind conditions to screen out the optimal mode of wing bag sand barrier. The analyses were conducted under nine configuration modes through the wind tunnel simulation experiment and the field experiment.Results: The inflection point of the airflow was always 5H on the windward side of the wing bag sand barrier, regardless of the wind speed. The protection range of the wing bag sand barrier with the same specifications was gradually weakened with the increase of the wind speed. However, there was an upward trend in both total sand accumulation and sand accumulation of each height layer. When the wind speed was slower than 8 m/s, the sand accumulation behind the barrier was mainly concentrated in the 0–10 cm height layer, and when the wind speed was 12 m/s, it was mainly concentrated in the 30–60 cm height layer. At the leeward side of the wing bag sand barrier, sand particles were rejected in the range of 0–30 cm; however, they were conducted in the range of 30–60 cm. The protective effect of the wing bag sand barrier simulated in the wind tunnel experiment was consistent with that of the field experiment.Discussion: For a wind speed of slower than 6 m/s, the recommended specification for the field-installed wing bag sand barrier was 25 cm × 20 cm or 30 cm × 20 cm. The specifications 25 cm × 20 cm and 25 cm × 25 cm were recommended at an inlet wind speed of 8 m/s. When the wind speed was greater than 12 m/s, the recommended specifications were 25 cm × 25 cm, 25 cm × 20 cm, and 20 cm × 25 cm.

Many rivers are tightly coupled and intersected with aeolian sand dunes, whose geomorphological evolution involves not only fluvial processes but also aeolian processes that pose a new challenge to fluvial geomorphological studies. However, due to few field studies, our overall understanding of the desert channel geomorphic process is limited. In this paper, we present an outstanding example of desert river channel evolution regulated by aeolian–fluvial interactions in the Ulan Buh Desert of the Yellow River, based on a long time series data set (1966–2019) of channel cross-sections. The results indicate that the lateral addition of aeolian sand, the water–sediment relationship and human interference have a significant role at different periods of channel evolution. Before 1986, higher discharge, lower sediment content and greater intensity of aeolian activity caused aeolian–fluvial interactions and a relative scouring and silting balance in the channel, with little human activity. From 1986 to 2000, an increase in large reservoir operation, vegetation coverage and floodplain farming, coupled with water–sediment relationship variation, caused rapid deposition and shrinkage of the river channel. From 2000 to 2014, the channel kept a slight scouring state. With Haibowan reservoir operation beginning in 2014, the talweg experienced rapid scouring and undercut rebound. However, an expanding and stable floodplain accelerated sedimentation on the floodplain and weakened river lateral erosion, indicating that the channel has shown a shrinkage trend. Meanwhile, wavelet analysis results indicate that human interferences and aeolian activities have no significant role in the periodical characteristics of the channel’s longitudinal erosion and deposition. Therefore, on the whole, increasing human interferences and decreasing wind dynamics have driven this desert wandering channel to be stable, and to gradually form a new balance between erosion and sedimentation.

Desert farmland provides food for desert areas, but water is the main limiting factor of this region, thus desert farmland has an extremely fragile ecological environment. This study investigated the temporal and spatial variations of vegetation NDVI (Normalized Difference Vegetation Index) in the Ulan Buh Desert, China, from 1990 to 2022, using long-term Landsat satellite data obtained from the Google Earth Engine platform and local statistical data. The results showed that from 1990 to 2022, the NDVI exhibited relatively small fluctuations and a steady increase. Furthermore, the study analyzed the impact of climate factors, namely precipitation and temperature, on NDVI, and collected the groundwater lever changes under irrigation and farmland development. The results demonstrated a positive correlation between NDVI and both precipitation and temperature from 1990 to 2006. The study area experienced an overall trend of increasing humidity. Specifically, from 1990 to 2006, significant positive correlations with precipitation and temperature were observed in 4.4% and 5.5% of the region, respectively. From 2007 to 2022, significant positive correlations were observed in 5.4% and 72.8% of the region for precipitation and temperature, respectively. These findings suggest that temperature has become increasingly influential on vegetation NDVI, while the impact of precipitation remains relatively stable. Moreover, the study assessed the impact of human activities on vegetation NDVI. The results revealed that from 1990 to 2006, human activities contributed to 43.1% of the promotion of local vegetation NDVI, which increased to 90.9% from 2007 to 2022. This study provides valuable insights into the dynamics of vegetation in the Ulan Buh Desert and its response to climatic changes and human activities. The findings highlight the significance of climate conditions and human interventions in shaping the vegetation dynamics in the region, offering essential information for ecological restoration and conservation efforts.

A clear understanding of the spatiotemporal evolution and driving factors of ecosystem service value (ESV) and the landscape ecological risk index (ERI) can effectively link human well-being and ecosystem security, which is essential for sustainable ecosystem management. Based on multitemporal land use data (1990, 2000, 2010, and 2018), the spatiotemporal evolution of ESV and the ERI in the Ulan Buh Desert was evaluated. The driving forces of ESV and the ERI were quantitatively evaluated by the Geodetector model. The results show that 1) from 1990 to 2018, total ESV in the Ulan Buh Desert increased from 7.00×108 yuan to 11.09×108 yuan. Low-ESV areas accounted for approximately 72.28% of the study area. High-ESV and moderate-high-ESV areas were mainly distributed along the Yellow River and the northeastern region. 2) During the study period, the ecological risk of the Ulan Buh Desert generally decreased; only the ecological risk of the northeastern region improved significantly, and high-risk areas were mainly distributed across sand dunes located in the middle of the desert. 3) There was a negative correlation between ESV and the ERI in the study area, and the main relationship was low value-high risk. 4) Driving force analysis results show that natural and human impact factors jointly affected the spatiotemporal differentiation of ESV and the ERI in the Ulan Buh Desert. Among the influencing factors, the interaction between the distance to a highway and annual precipitation had the strongest impact. The implementation of relevant policies in the study area should be guided by ESV and the ERI, and the protection and restoration of various ecosystems in the study area must be strengthened.

What is the water source for ecological restoration plants in arid region is still up to debate. To address this issue, we conducted an in-situ experiment in the Ulan Buh Desert of China. We selected Tamarisk, a common drought-salt-tolerance species in the desert for ecological restoration as our research subject, used a new designed lysimeter to monitor precipitation infiltration, a sap flow system to track reverse sap flow that occurred in shoot, branch, and stem during the precipitation event, and observed the precipitation redistribution process of the Tamarisk plot. The results showed that Tamarisk indeed directly absorb precipitation water, when precipitation occurs, the main stem, lateral branch, and shoot all show the signs of reversed sap flow, and the reversed sap flow accounted for 21.5% of the annual sap flow in the shoot and branch, and 13.6% in the stem. Precipitation event in desert was dominated by light precipitation events, which accounted for 81% of the annual precipitation events. It was found that light precipitation can be directly absorbed by the Tamarisk leaves, especially in nighttime or cloudy days. Even when the precipitation is absent, it was found that desert plants can still absorb unsaturated atmospheric vapor, as reversed sap flow was observed when the atmospheric relative humidity reached 75%. This study indicated that the effect of light precipitation on desert plants was significant and should not be overlooked in terms of managing the ecological and hydrological systems in arid regions. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As a typical desert in the Inner Mongolia Autonomous Region, the Ulan Buh Desert has a dry climate and scarce precipitation all year round. Groundwater has become the main factor limiting the growth of vegetation in this region. It is of great significance to study the influence of groundwater depth on the spatial distribution pattern of vegetation in this region. Based on the PIE-Engine platform and using long-term time-series Landsat data, this paper analyzed the spatial–temporal distribution characteristics and trends in vegetation coverage in the Ulan Buh Desert in the last 20 years using a pixel dichotomy model and the image difference method. The Kriging interpolation method was used to interpolate the groundwater depth data from 106 monitoring wells in the Ulan Buh Desert over the past 20 years, and the spatial distribution characteristics of groundwater depth in the Ulan Buh Desert were analyzed. Finally, the correlation coefficient between changes in vegetation coverage and changes in groundwater depth was calculated. The results showed the following: (1) The vegetation coverage in the Ulan Buh Desert was higher in the periphery and lower in the center of the desert. The overall vegetation level showed an increasing trend year by year; the growth rate was 4.73%/10 years, and the overall vegetation cover showed an improving trend. (2) The overall groundwater depth in the Ulan Buh Desert was deep in the southwest and shallow in the northeast. In the past 20 years, the groundwater depth in the Ulan Buh area has become shallower, and the ecological condition has gradually improved. (3) On the whole, the vegetation coverage varied with the groundwater depth, and the shallower the groundwater depth, the greater the vegetation coverage. When the groundwater depth increased to more than 4 m, the change in the groundwater depth had a significant effect on the vegetation coverage. However, when the groundwater depth was greater than 6 m, the change in the groundwater depth had no significant effect on the change in vegetation coverage.

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Knowledge of the microclimate and wind regimes of different land landscapes can be used to support natural resource development and agricultural productivity in desert areas. The aim of this study is to provide a theoretical basis and technical support for the management of Ulan Buh Desert Oasis and the comprehensive prevention and control of sandstorms from the surrounding desert in northern China. We examined the microclimate and wind regime of three landscapes—desert, desert–oasis ecotone, and oasis—and discussed the factors underlying the observed variations. Similar patterns were found in annual temperature, annual relative humidity, and wind speed between the desert, desert–oasis, and the oasis. Compared with the desert and the desert–oasis ecotone, the average annual temperature and wind speed in the oasis were lower by 2.56%–5.38% and 32.99%–37.05%, respectively. Average annual relative humidity in the oasis was higher than in other areas by 1.31%–2.57%. The desert, desert–oasis ecotone, and the oasis were dominated by westerly winds. Wind direction was relatively stable in the oasis and variable in the desert and desert–oasis ecotone. There were intermediate wind energy fields in the desert and the desert–oasis ecotone and a low wind energy field in the oasis. In the desert–oasis ecotone, drift potential (DP), resultant drift potential (RDP), and resultant drift direction (RDD) were 231.87 VU, 97.21 VU, and 104.33°, respectively. In the desert, DP was 228.45 VU, RDP was 92.65 VU, and RDD was 76.05°. In the oasis, the DP was 61.85 VU, RDP was 38.04 VU, and RDD was 92.97°. In the desert and the desert–oasis ecotone, sediment transport potential was the highest in spring, second highest in autumn, third highest in winter, and lowest in summer. In the oasis, it was the highest in winter, second highest in autumn, third highest in spring, and lowest in summer. There are complex variations in the dominant sediment transport directions in the desert and desert–oasis ecotone in the study area. Variations in the dominant sediment transport direction in the oasis are less complicated and are associated with the seasons. The oasis is primarily threatened by sandstorms from the south-southeast in spring.

A highly urgent need has been concerned to more conveniently monitor the moving speed of dunes along the Yellow River in the Ulan Buh Desert. Taking the coastal dune in Ulan Buh Desert as the research object, the seasonal geomorphological process and influencing factors were investigated using image data acquisition through UAV in this study. Results showed that: 1) The annual movement speed of dune was 1.08-2.27m/a, the multi-year average sand Drift Potential (DP) was 78.82 VU, and the annual Resultant Drift Potential (RDP) was 25.96 VU. It indicated that the study area was in a low wind energy environment. The 8-12 m/s level of sand DP accounted for 73.24% of annual sand DP. The intermediate directional wind variability (i.e. RDP/DP) was around 0.30-0.46. The average Resultant Drift Direction (RDD) was 88.40°, which was consistent with the dune movement direction. The westerly wind contributed 52.09% of the variation of the annual sand DP, indicating the main driving force for the annual movement of dunes. 2) The dune movement speed presented obvious seasonal characteristics. Specifically, the fastest was observed in spring, followed by late winter to early spring, and the slowest in summer. In late autumn to late winter, spring and autumn, the sand DP was around 8.48-20.49 VU, the RDD was 90.02°-95.54°, and the RDP/DP was 0.3-0.8, indicating an intermediate rate of directional wind variability. The westerly wind presented a significant effect on dune movement, particularly compatible with the annual RDD and dune movement direction. In late winter to early spring and late spring to summer, the dune with a relatively low movement speed usually adapted to the wind direction through morphological changes under the northeasterly wind (NE) and southerly wind (SSE, S, and SSW). The seasonal sand DP was mainly composed of 8-10 m/s level wind speed, accounting for 40.76%-56.93% of the whole season. 3) Overall, the seasonal and inter-annual sand DP was linearly positively correlated with dune movement distance. The fitting equation was y=1.02+0.006 62x (R ²=0.339, F=5.615 9, P=0.045 26). The fitting equation reached a significant level, indicating that the sand DP can be used to characterize the dune movement distance in the area. The comprehensive landscape was achieved for the dune movement monitored by UVA. Consequently, the wind speed above 8 m/s in the Westerly Group was the main driving force for dune movement in the study area. When the wind direction variability and the RDP were consistent with the movement direction of dunes, the dunes moved faster, otherwise, the dunes moved slowly. Anyway, UAVs can provide more convenient monitoring services for the movement of dunes on a larger scale. This finding can also provide a strong reference for UVA monitoring of dune movement in similar areas. [ABSTRACT FROM AUTHOR]

• The northern UBD and YD have similar trace metal compositions and source areas; • The BJD and southern Mongolian Gobi are the main direct sources of the UBD; • Nd isotopes indicate ∼ 25% input from the LM for sands in the northern UBD; • The northern UBD and YD act as an intersection for long-distance aeolian transport. Tracing the provenance of aeolian sand in deserts is essential for comprehending the mechanisms underlying desert formation and sediment transportation processes. There are multiple sand belts that interconnect major deserts within the Alxa Plateau of northern China, as evidenced by satellite images and field research. However, the aeolian sand transport from the Badain Jaran Desert (BJD) to the Yamalik Desert (YD) and Ulan Buh Desert (UBD) through these expanding sand belts is still being underestimated. In this study, we analyzed trace metal contents and Sr-Nd isotopic compositions in the < 125 μm fraction of dune sands in the northern UBD and YD, along with bedrocks from the Langshan Mountains (LM). Based on bivariate plots of Zr vs. Hf, Zr/Hf vs. Hf, Cr/V vs. Y/Ni, and Th/Co vs. Th/Sc, the aeolian sands in the northern UBD and YD have similar sources but are different from those in the southern UBD. Comparison of Sr-Nd isotopes with potential source areas suggests that fine-grained aeolian sands in the YD and northern UBD are mainly sourced from the BJD and the southern Mongolian Gobi. Although the heterogeneity of bedrock samples impeded the precise interpretation of contributions from all potential sources, the ε Nd (0) signatures in the UBD suggest that up to 25% of the fine-grained sand is derived from the LM, which displays highly negative ε Nd (0) values. On a larger geographical scale, the northern UBD serves as a transfer intersection for long-distance transportation of sand and dust ultimately sourced from the Central Asian Orogen and northern Tibetan Plateau. This study also demonstrates the essential role of sand belts in facilitating aeolian transport within the Alxa Deserts. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Microclimate characteristics of different underlying surfaces can pose a practical challenge to utilize climate resources for the normal growth of crops in desert areas. In this study, the microclimate differences were systematically analyzed in the three typical underlying surfaces. The data, including the air temperature, relative humidity (RH), wind speed and wind direction in desert area, desert-oasis ecotone and oasis in the northeastern of Ulan Buh Desert, were collected in synchronous observation from the “National Observation Station of Inner Mongolia Dengkou Desert Ecosystem” during January to December, 2018. The results showed that there were significantly different effects of the properties of underlying surface on microclimate characteristics. 1) The annual temperatures in desert area, desert-oasis ecotone and oasis were 9.66, 9.38 and 9.14 ℃, respectively. There were few differences in daytime between the three underlying surfaces, but great differences in night. There was obviously inversion phenomenon within 50 m above the ground, where the vegetation has the function of cooling and humidification in the high temperature season, whereas, it has a heat preservation effect in winter. The temperatures of the desert-oasis ecotone and the oasis increased by 0.05 and 0.18 ℃, compared with that of the desert area in the winter, while those decreased by 0.38-1.50 ℃ and 0.22-2.58 ℃, respectively, in spring, summer and autumn. 2) The annual and diurnal variations of relative humidity remained consistent in desert area, desert-oasis ecotone and oasis. The annual average relative humidity in the oasis increased by 1.31 to 2.57 percentage points, compared with that in the desert-oasis ecotone and desert area. In terms of seasons, the relative humidity in the oasis was 4.04-6.17, 0.93-1.94 percentage points higher than that in the desert area and the desert-oasis ecotone in summer and autumn. The relative humidity inside the oasis was 0.37-1.41percentage points, 6.55-8.71 percentage points lower than that in the desert area and the desert-oasis ecotone. The reason can be that the humidity inversion phenomenon occurred within 50 m above the ground. 3) The annual variations of wind direction were similar in the desert area and desert-oasis ecotone, where the main directions were the westerly winds (SW, WSW, W, WNW). The wind direction was changeable in the desert area and desert-oasis ecotone, whereas that relatively concentrated in the oasis. The average annual wind speed was reduced by 32.99%-37.05% in the oasis, compared with that in the desert-oasis ecotone and the desert area, indicating that the vegetation can effectively decrease the wind speed. Comprehensive analysis showed that the vegetation and oasis shelter forest systems in the transition zone of the northeastern of Ulan Buh Desert posed a good regulation effect on microclimates, such as cooling, humidifying, and reducing wind. The local microclimate in the study area demonstrated that the wind speed and humidity in summer and autumn, while, the temperature and humidity of spring and winter were mainly affected by inverse temperature and humidity. This finding can provide a theoretical basis to explore the microclimate ecological characteristics in arid areas, as well ecological protection and reasonable construction of oasis in desert areas. [ABSTRACT FROM AUTHOR]

Knowledge of moisture sources is of great significance for understanding climatic change and landscape evolution in desert environments. In this paper, we aim to clarify moisture origins for the Alashan (Alxa) Sand Seas (ALSS) in western Inner Mongolia and their transport pathways during the Last Glacial Maximum (LGM) and the mid-Holocene using modern analogues and paleoclimatic simulations. Precipitation data for the period 1959–2015 from meteorological stations in the study area and wind and specific humidity data from the European Center for Medium-Range Weather Forecasts (ECMWF) daily re-analysis were adopted to determine the moisture sources of summer precipitation in the ALSS. In addition paleoclimate simulations under PMIP3/CMIP5 protocols were used to detect the atmospheric circulation and precipitation at 21 ka BP and 6 ka BP over the ALSS. We also reviewed paleoclimate records from the ALSS to acquire a semi-quantitative re-construction of the moisture history during the late Pleistocene and Holocene. Our results suggest that the summer monsoon transported water vapor from the Indian Ocean and the South China Sea to the ALSS during July and August, causing increased precipitation. The dominant moisture source was from the southwest monsoon, while the East Asian summer monsoon also partly contributed to precipitation in the ALSS. The increased humidity during the period 8.2–4.2 ka BP in the ALSS, as derived from both climate simulation outputs and sedimentary records, was caused by monsoons according to the outputs of simulations. At 21 ka BP, the moisture sources of the ALSS were greatly associated with the prevailing westerlies. [ABSTRACT FROM AUTHOR]

Desertification is a primary threat to crop farming, the livestock industry, and the eco-environment in northwestern China. Through field research and satellite imagery, it has been discovered that there are 4-5 sand belts in the shape of handclasps connecting major deserts in the Alxa Plateau region of northern China. These sand belts have been expanding for several decades. However, eolian sand transport between major deserts through these expanding sand belts is still underestimated. Identifying the source areas of eolian sands in deserts provide essential knowledge to prevent desertification. In this study, we collected samples from the northern Ulan Buh Desert (UBD), the Yamalik Desert (YD), and the Langshan Mountains and analyzed their REE contents in the <125 μm fraction. We compared REE geochemical characteristics of fine-grained sands in the UBD with other recently published REE data for potential source areas. Our findings indicate that the primary origins of fine-grained sands in the northern UBD are from the Qilian Mountains (QM) and Badain Jaran Desert (BJD), which are transported through the YD. Contributions from the Gobi-Altay Mountains to the north are relatively minor. The Langshan Mountains and Hawula Mountains are not considered as the primary sources of fine-grained sands in the UBD. In contrast, surface sediments in the southern UBD have a local mixture of the paleo-lacustrine deposits, the Gobi sediments, and minor external inputs from the BJD and QM. Our findings demonstrate that sand belts connecting these deserts play a crucial role in the eolian transport of fine-grained sands. Therefore, both the Chinese government and scientists should pay close attention to them in future efforts to combat desertification., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 Published by Elsevier Ltd.)

This paper used the radioisotope (14C) dating and chloride mass balance to reveal groundwater age and groundwater recharge rates in Ulan Buh Desert. The results show that the saturated zone groundwater age range from 22 000 years to now by the 14C dating and correction. The chlorine mass balance deduces that the groundwater age at 5.5 m in the unsaturated zone is 2 645 a. The recharge rates of unsaturated zone groundwater range from 0.19 mm/a to 2.55 mm/a with a mean of 1.12 mm/a. Therefore, the amount of direct recharging for phreatic and confined water is also minimal from the unsaturated zone. [ABSTRACT FROM AUTHOR]

Abstract Aeolian sand transport into rivers is a crucial factor influencing channel sediment dynamics and fluvial processes in rivers that flow through desert areas. Few studies have examined the dynamic processes, controlling factors, and the amount of aeolian sand transported into river channels. Here, we report a case study of aeolian sand transport into in the upper reaches of the Yellow River as it flows along the eastern margin of the Ulan Buh Desert, which is a major desert in northern China. The present study is based on systematic monitoring of wind flow characteristics, aeolian sediment dynamics (saltation, creep and suspension), and the migration of typical sand dunes (mobile, semi-anchored, and anchored) from 2013 to 2016. The relationship between wind speed and wind-blown sand transport in the study area was determined. The relationship between the rate of aeolian sand transport (saltation and creep) and the wind speed 2 m above the ground surface can be depicted with a polynomial relation when the wind speed is ≥5.7 m/s, and with a power function when the wind speed is <5.7 m/s. Dune migration mainly occurred during March to May, and the dune migration rate was influenced by wind speed and other factors such as dune height and vegetation conditions. The rate of aeolian sand transport by wind-blown sand flow (particle saltation, creep, and suspension) and sand dune migration were calculated, and the annual aeolian sand transport rates into the river channel in 2013, 2014, 2015 and 2016 were estimated to be 1.47, 0.86, 0.52, and 0.50 million t/yr, respectively. These results are significantly lower than previous estimates made between the 1980s and 2000s. The decrease in sand flux may be attributed to the regional decline in wind speed over the last six decades which has caused a sharp reduction of the aeolian sand transport rate, the improved vegetation coverage in this area which has reduced the area of active and mobile dunes, and an embankment constructed adjacent to the Yellow River which has suppressed aeolian sand migration into the river channel. Highlights • Aeolian sand flux of the Ulan Buh Desert into the upper Yellow River is reevaluated. • In situ monitoring and survey of aeolian sand flux was conducted from 2013 to 2016. • Sand flux is evidently lower than previous estimates made from the 1980s to the 2000s. • Wind speed decline, improved vegetation, and channel embankment contribute to sand flux decrease. [ABSTRACT FROM AUTHOR]

The current researches of near surface sand movement pay more attention to the short period and single direction of the blowing sand structure characteristics, but the results were difficult to combine with the long-term geomorphological processes. The sand drift potential (DP) and sediment transport are two important index to reflect windblown sand activity intensity. In order to prove the characteristic of sand-drift activities of the blown-sand movement in the northeast edge of Ulan Buh Desert, we studied the variations of sand-driving wind regime, drift potential and sediment transport rate in the northeast edge of Ulan Buh Desert, and the dates of the annual wind speed, direction and sediment transport data were collected from the “Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station” during 2013-2017. We analyzed the dates by the methods of field observation, laboratory analysis and calculation. The results showed that: 1) the mean speed, frequency and maximum speed of sand-driving wind in the northeast edge of Ulan Buh Desert were 6.77 m/s, 19.74% and 20.76 m/s, respectively. These indexes were all largest in spring, the value were respectively 7.10 m/s, 24.63% and 18.43 m/s, which was main sandstorm activity period, followed by autumn, and were all smallest in winter, the value were6.53 m/s, 17.61% and 13.60 m/s, respectively. 2) The sand-driving wind direction of four seasons and the whole year were consistent with each other in the northeast edge of Ulan Buh Desert, and the main directions these were the easterly winds (NNE, NE, ENE, E) and the westerly winds (SW, WSW, W, WNW. 3) The yearly sand drift potential and the resultant drift potential(RDP) were respectively 183.38 VU and 73.41 VU, which belongs to an intermediate wind energy environment, and the yearly index of directional wind variability (RDP/DP) was 0.40, which belongs to a intermediate ratio. The yearly resultant drift direction (RDD) was 111.15°, which indicated the southeast by east direction. The sand material of the northeast edge of Ulan Buh Desert move to southeast by east direction. The seasonal variation characteristics and monthly variation characteristics in spring of the sand drift potential and the resultant drift potential, the sand drift potential and the resultant drift potential were largest in May, followed by November, and the smallest in January. 4) The sand transport quantity of the sixteen directions of northeast edge of Ulan Buh Desert was 35.11 kg/m·d, the sediment transport quantity of the WNW direction reached the maximum and the value was 3.21 kg/m·d, and the sediment transport rate showed obvious seasonal variation characteristics, while the sand transport quantity of spring was significantly higher than other seasons. The research results provide a basis for the ecological environment assessment of the northeast edge of Ulan Buh Desert, and provide a theoretical basis for regional desertification prevention and control measures. [ABSTRACT FROM AUTHOR]

Industrial symbiosis (IS), which is a concept that allows enterprises to reduce material consumption and production cost, is widely used to optimize eco-industrial parks (EIPs). However, the IS formed in different regions and industrial fields may have different performances in terms of environmental, economic, and social aspects, and few studies are focusing on the IS optimization of material exchange relationships in EIPs in desert areas. Therefore, a multi-objective mixed-integer linear programming (MILP) model is proposed in the present study to optimize the environmental, economic, and social objectives of IS in Ulan Buh Demonstration Eco-industrial Park (UBD-EIP). Then the model is solved using the augmented ε-constraint method and 20 efficient solutions are obtained. The results show that the construction of IS can reduce the environmental impact by 50.24%–50.79%, decrease the operating costs by 42.95%–43.57%, and create a considerable number of job opportunities. The trade-off between environmental and economic objectives suggests that an increase in priority for economic objectives results in higher levels of raw material consumption and waste emissions. The proposed model can help decision-makers of EIPs to choose appropriate material exchange relationships according to objective priority choices. This article enriches the types of objective functions for multi-objective optimizations and provides a reference for IS optimization and sustainable development of industries in desert areas and mixed agricultural-industrial systems. [Display omitted] • A multi-objective MILP model is proposed considering sustainability in desert areas. • IS is optimized in the EIP of desert areas based on field investigation data. • IS can improve environmental and economic performance and provide considerable jobs. • Raw material use and waste emissions increase as economic objective priority rises. • Changes in production sector capacity affect the IS structure significantly. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Irrigated farmland is the main food source of desert areas, and moisture is the main limiting factor of desert farmland crop productivity. Study on the influence of irrigation on desert farmland soil moisture can guide the agricultural water resource utilization and agricultural production in those regions. At present, the efficiency of irrigation water usage in Northwest China is as low as approximately 40% of the irrigated water. To understand the response of farmland soil moisture in different soil types on irrigation in the Ulan Buh Desert of Inner Mongolia of China, this experimental study takes advantage of different infiltration characteristics and hydraulic conductivities of sand, clay, and loam to determine an optimized soil combination scheme with the purpose of establishing a hydraulic barrier that reduces infiltration. This study includes three comparative experiments with each consisting of a 100 cm thick of filled sand, or clay, or loam soil underneath a 50 cm plough soil, with a total thickness of 150 cm soil profile. A new type of lysimeter is installed below the above-mentioned 150 cm soil profile to continuously measure deep soil recharge (DSR), and the ECH2O-5 soil moisture sensors are installed at different depths over the 150 cm soil profile to simultaneously monitor the soil moisture above the lysimeter. The study analyzes the characteristics of soil moisture dynamics, the irrigation-related recharge on soil moisture, and the DSR characteristics before and after irrigation, during the early sowing period from 2 April to 2 May 2017. Research results show that: (1) Irrigation significantly influences the soil moisture of 0-150 cm depths. The soil moisture increase after the irrigation follows the order from high to low when it is in the order of loam, sand, and clay. (2) Irrigation-induced soil moisture recharge occurs on all three soil combinations at 0-150 cm layers, and the order of soil moisture recharge from high to low is: clay (54.3 mm, 43.39% of the total irrigation), loam (39.83 mm, 31.83% of the total irrigation), and sand (33.47 mm, 26.75% of the total irrigation). (3) After the irrigation event, DSR below 150 cm occurs for all three soil combinations. This study reveals the characteristics of irrigation-induced soil moisture recharge and DSR, and it shows that farmland consisting of an upper 50 cm plough soil and a lower 100 cm filled clay soil can save more water resource at the study site, which is useful in agricultural control measure and water resource management in arid regions. [ABSTRACT FROM AUTHOR]

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The Ulan Buh Desert has a fragile natural environment, which is in the western part of Inner Mongolia arid climate zone and the farming and animal husbandry ecotone. In order to explore the driving force mechanism of the Land Cover Change, the paper constructed the natural-human driving force model by the Markov Chain based on Landsat MSS 1973,1977 remote sensing image data, analyzed the natural-human driving force contribution rate to the Land Cover Change in Ulan Buh Desert The results showed that in 1989-2013 the main driving force of the Ulan Buh Desert Land Cover Change is the natural factors, average contribution rate is 89.46%, then is the human driving force, the rate is 10.54%. The natural-human driving force contribution rate for every land cover type is different, in natural part, the minimum rate is saline-alkali land for 45.20%, while the maximum is sandy land (90.63%). The human driving force rate of forest land, grassland and water was negative, it shows that human factors slows down or hinder the growth of this kind of land cover. Because of the humanistic attribute, the natural effect of the cultivated land and construction land was abandoned, die rates of human driving are significantly different the change of human driving force is 24.94%, while the change of construction land is 62.9%. [ABSTRACT FROM AUTHOR]

Deserts are the main source of dust storms in the surface layer, aeolian sand-dust transport is a serious problem in many arid and semi-arid regions in the world, and it is considered to be a significant part of global biogeochemical cycle. Aeolian dust transport processes are closely related to the variation of the height of near-surface horizontal and deposition dust flux. Ulan Buh Desert is one of the 8 largest deserts in China, and is also one of the important dust source regions in northern China. In this paper, fixed monitoring stations were set up in both the desert-oasis ecotone and the oasis at the northeast edge of Ulan Buh Desert, the near-surface (0-50 m) wind speed and sand-dust flux data obtained from the dust observation tower at the Inner Mongolia Dengkou Desert Ecosystem Research Station of the State Forestry Administration in 2013 were analyzed to reveal the spatio-temporal variation characteristics of wind speed and sand-dust flux at the northeast edge of Ulan Buh Desert. The results showed as follows: 1) Both the average wind speed of the year and the average wind speed of different seasons of the near-surface layer in both desert-oasis ecotone and oasis increased with the increase of the height, and the wind speed profile characteristics could be expressed by power exponential function. The wind speed in the desert-oasis ecotone was significantly higher than that in the oasis. 2) The near-surface horizontal sand-dust flux and dust-falling amount in both desert-oasis ecotone and oasis decreased with the increase of the height, and the distribution characteristics also accorded with power exponential function. The horizontal sand-dust flux in the oasis-desert ecotone was significantly higher than that in the oasis, which obviously indicated that the protection forest in the oasis has the effects of weakening the transportation of sand dust. The horizontal sand-dust flux and dust-falling amount in the desert-oasis ecotone had a linear correlation relationship, while the horizontal sand-dust flux and dust-falling amount in the oasis showed an exponent relationship. 3) The variation characteristics of horizontal sand-dust flux and dust-falling amount in the artificial oasis and the oasis-desert ecotone were gradually decreased with the increase of the height in the 4 seasons of a year, the horizontal sand-dust flux and dust-falling amount were concentrated in spring, followed by summer, while those in autumn and winter were relatively low; the horizontal dust flux and the dust-falling amount of oasis-desert transition belt were significantly higher than the inner oasis. The horizontal dust flux and dust-falling amount in the oasis-desert ecotone were significantly higher than that in the oasis in all 4 seasons of a year. The results reveal the spatio-temporal variation rules of near-surface wind speed and sand-dust activity, and illuminate the mechanism of the effects of oasis protection forest on weakening surface wind speed and sand-dust activities, which can help to provide a theoretical basis and reference for the desertification combating and the establishment of oasis protection forest. [ABSTRACT FROM AUTHOR]

[Objective] To establish drought resistance evaluation index system of desert shrubs, and provide scientific support for selecting quality tree species. [Method] Taking 2-year-old seedlings of 12 desert shrubs in Ulan Buh Desert ecosystem as the test materials, 7 water physiological indexes were tested, principal component analysis and cluster analysis were applied to explore drought resistance of the shrubs. [Results] (a) Water potential of Ephedra, distachya Linn., Nitraia tangutorum Bobr., Caragana korshinskii Kom. was lower than that of the other 9 species; bound water content (Va) and bound water/free water ratio (Va\Vs) of ZygophyUum xanthoxylon Maxim, was 64.20% and 3.3, higher than the others'; transpiration rate of Atraphaxis bracteata A. Los., Nitraia tangutorum Bobr. and Tamarix elongata Ldb. was significantly lower than the others'; constant weight time of Haloxylon ammodendron (C. A. Mey.) Bunge and Ephedra distachya Linn, was the longest (144 h); residual moisture content of Ammopiptanthus mongolicus Maxim, was the highest (44.80%). (b) Water potential, bound water/free water (Va/Vs), residual moisture content, bound water, constant weight time, and transpiration rate had great impact on drought resistance of plant, and the accumulative variance contribution rate achieved 87.59%. [Conclusion] According to the drought resistance, the 12 species were classified into 3 categories, namely shrubs with strong drought resistance (Ephedra distachya linn.), shrubs with moderate drought resistance (Haloxylon ammodendron (C. A. Mey.) Bunge, Nitraia tangutorum Bobr., and ZygophyUum xanthoxylon Maxim.); shrubs with poor drought resistance (Hedysarunn scoparium Fisch, Hedysarum mongolicum Turcz., Tamarix elongata Ldb., Caragana korshinskii Kom., Ammopiptanthus mongolicus Maxim., Atraphaxis bracteata A. Los., Calligonum mongolicum Mattel, and Caragana microphyila Lam.). [ABSTRACT FROM AUTHOR]

Hetao Plain, composed of hundreds of oases, is one of the most important grain-producing areas in China. Most crops, especially wheat and corn, depend on irrigation, thus water availability is a key issue for grain productivity on this land. The Yellow River is the main water source for irrigation and a crisis of water resources for agricultural use occurs because of increasingly reduced river flows and water-using competition with industry and human residential use. In order to understand the current situation and distribution of water resources on these oases, we collected 20-yr's data of river runoff, irrigation volumes, infiltration and precipitation to examine the relationships between water resources distribution and its agricultural use. We found that the oasis in Dengkou county was short of water resources with a water deficit rate of 5.14% in 2010. Based on the trend of the data, water deficit will continue to increase as the population grows in the future. Water resource is a limiting factor to agricultural development in this region and proper management of water use and strategies for water resource conservation are urgently needed. Especially, based on our results we suggest that current irrigation methods need to be greatly improved to save the water that was lost from evaporation.

Irrigated farmland is the main food source of desert areas, and moisture is the main limiting factor of desert farmland crop productivity. Study on the influence of irrigation on desert farmland soil moisture can guide the agricultural water resource utilization and agricultural production in those regions. At present, the efficiency of irrigation water usage in Northwest China is as low as approximately 40% of the irrigated water. To understand the response of farmland soil moisture in different soil types on irrigation in the Ulan Buh Desert of Inner Mongolia of China, this experimental study takes advantage of different infiltration characteristics and hydraulic conductivities of sand, clay, and loam to determine an optimized soil combination scheme with the purpose of establishing a hydraulic barrier that reduces infiltration. This study includes three comparative experiments with each consisting of a 100 cm thick of filled sand, or clay, or loam soil underneath a 50 cm plough soil, with a total thickness of 150 cm soil profile. A new type of lysimeter is installed below the above-mentioned 150 cm soil profile to continuously measure deep soil recharge (DSR), and the ECH2O-5 soil moisture sensors are installed at different depths over the 150 cm soil profile to simultaneously monitor the soil moisture above the lysimeter. The study analyzes the characteristics of soil moisture dynamics, the irrigation-related recharge on soil moisture, and the DSR characteristics before and after irrigation, during the early sowing period from 2 April to 2 May 2017. Research results show that: (1) Irrigation significantly influences the soil moisture of 0–150 cm depths. The soil moisture increase after the irrigation follows the order from high to low when it is in the order of loam, sand, and clay. (2) Irrigation-induced soil moisture recharge occurs on all three soil combinations at 0–150 cm layers, and the order of soil moisture recharge from high to low is: clay (54.3 mm, 43.39% of the total irrigation), loam (39.83 mm, 31.83% of the total irrigation), and sand (33.47 mm, 26.75% of the total irrigation). (3) After the irrigation event, DSR below 150 cm occurs for all three soil combinations. This study reveals the characteristics of irrigation-induced soil moisture recharge and DSR, and it shows that farmland consisting of an upper 50 cm plough soil and a lower 100 cm filled clay soil can save more water resource at the study site, which is useful in agricultural control measure and water resource management in arid regions.

• The MixSIAR model can be used to trace the sediment source of aeolian sand. • The Mountains surrounding the Ulan Buh Desert are its dominant sediment source contributor. • Fine sands from the upwind areas of the Ulan Buh Desert plays a significant role in its sediment source. • Paleo-lacustrine sediments serve as a direct sediment source for the desert. • The coupling of fluvial and wind systems promotes the accumulation of the desert. Identifying and quantifying source contributions of aeolian sands in desert where extensive dunes and paleo-lakes coexist is crucial to elucidate the formation mechanism of aeolian and lacustrine landforms in the earth system. In this study, we identified the aeolian sediment sources in the Ulan Buh Desert (UBD) using geomorphological and sedimentological methods, and further quantified the source contributions via the sediment source fingerprinting (SSF) method within MixSIAR modelling framework. Our results revealed that the mean contribution from each source to the UBD sediments were assessed to be 32.2 % for detrital deposits weathered and eroded from the Helan Mountains (HLM), Bayan Urals Mountains (BUM), and Langshan Mountains (LM), 26.2 % for aeolian and Gobi deposits from the adjacent Yamalik Desert (YMD) and Bayin Wendur Desert (BWD), 26.1 % for aeolian and Gobi sediments from the upwind Badain Jaran Desert (BJD), and 15.5 % for the paleo-lacustrine sediments in the UBD. The bulk fraction sands in the UBD are mainly contributed by detrital deposits from its surrounding mountains, whereas the fine sands are supplied by the upwind deserts of the UBD. As shown by the dunes migration rate (averaged 9.1 m/yr) and direction (averaged 118.3°) in the YMD, sands from upwind desert can be easily transported to the adjacent downwind desert, i.e., the UBD. Therefore, much attention should be paid to their role in sediment source contribution rather than ignore them for their limited area. Similarly, although the sediment source contribution from paleo-lacustrine deposits within the desert is relatively small, they served as a direct source for the UBD. The GOF evaluation demonstrated that the MixSIAR Bayesian model is an effective approach to aid aeolian sediment fingerprinting. In addition, we found that the aeolian sediments in the UBD is the combined results of wind and fluvial systems. [ABSTRACT FROM AUTHOR]

The Ulan Buh Desert (UBD), in southwestern Inner Mongolia, is one of the main dune fields and dust source areas in northern China. The formation of the desert and associated environmental changes since the middle Pleistocene are still unclear due to a lack of depositional records and environmental proxy index analyses. In this study, quartz and K-feldspar optical dating, environmental proxy indexes of grain size, loss on ignition, pollen, and ostracod analysis were employed to supplement the sediment record of a 120.5 m drill core, WL12ZK-1, from the southern UBD. In combination with previous stratigraphic records obtained from drill cores WL10ZK-1 (35 m deep) and WL10ZK-2 (32 m deep) from the northern UBD, and drill core WL12ZK-2 (80 m deep) from the northeastern UBD, these proxies indicate there has been essentially an arid environment in the UBD, with desert or steppe vegetation, since the middle Pleistocene, and that sand dunes were widely distributed in the UBD beginning at least ∼230 ka ago. The Yellow River filled a freshwater paleolake beginning ∼15 ka ago that covered both the UBD and the adjacent Hetao Plain. The paleolake lasted until ∼87 ka, and was associated with wetlands along its margins. Steppe vegetation was present in the surrounding region. An arid environment appeared again after ∼87 ka, and there is no evidence of a large stable lake in the UBD at any time thereafter. Sand dune deposition and a very arid desert environment were present throughout the last glacial period and lasted into the early Holocene. During the Holocene these arid conditions were interrupted by minor wetland intervals. Deserts in southern Inner Mongolia formed at least since the middle Pleistocene, expanded during the last glaciation and into the early Holocene and again after ∼2 ka. We suggest that a combination of tectonic activity and climate change may be responsible for desert formation and environmental changes in southern Inner Mongolia since the middle Pleistocene, with additional human influence exacerbating these conditions in the late Holocene. [ABSTRACT FROM AUTHOR]

Understanding the changes and influencing factors of soil organic carbon density (SOCD) during the conversion of uncultivated natural soil to croplands is of great significance for the assessment of carbon sequestration in arid areas. In this study, we compared SOCD in the uncultivated soil and that in croplands with different cultivation years (2-5, 12-15, 25-30, 40-50 years) in the Northeastern Ulan Buh Desert. The change of SOCD and its influencing factors at 0-2 m soil depth during the conversion of uncultivated natural soil to croplands were explored by the method of replacing time with space. The results showed that SOCD at the shallow soil depth (0-0.4 m) in croplands increased continuously with cultivation years, but basically at low levels (0.990-1.983 kg·m -2 ). The SOCD at deep soil (1.2-2 m) increased in the croplands with longer cultivation years (25-30 and 40-50 years), whereas no obvious change trends in both the croplands with shorter cultivation years (2-5 and 12-15 years) and the uncultivated natural soil. The SOCD at deep soil (1.2-2 m) were relatively large (28.9%-38.6%) of the 0-2 m soil depth of uncultivated natural soil and croplands with different cultivation years. The vertical distribution of SOCD in croplands with different cultivation years were well fitted by quadratic functions (with R 2 ranging from 0.757 to 0.972). It was noteworthy that soil clay and silt contents had dominant influences on SOCD at all the soil profile (0-2 m), and that cultivation years mainly contributed to the accumulation of SOC at the shallow soil (0-0.4 m).

Abstract: The evolution of arid environments in northern China was a major environmental change during the Quaternary. Here we present the dating and environmental proxy results from a 35m long core (A-WL10ZK-1) collected from the Ulan Buh Desert (UBD), along with supplemental data from four other cores. The UBD is one of the main desert dune fields in China and our results indicate the UBD has undergone complex evolution during the late Quaternary. Most of the present UBD was covered by a Jilantai-Hetao Mega-paleolake lasting until ~90ka ago. A sandy desert environment prevailed throughout the UBD during the last glacial period and early Holocene. A wetland environment characterized by the formation of numerous interdunal ponds in the northern UBD occurred at ~8–7ka, although a dune field persisted in the southern UBD. The modern UBD landscape formed after these wetlands dried up. During the last 2000years, eolian sand from the Badain Jaran Desert has invaded the northern UBD, while farming and overgrazing resulted in the formation of the eastern UBD. We suggest that the formation of UBD landforms is related to the disintegration of the megalake Jilantai-Hetao and to summer monsoon changes during the last glaciation and Holocene. [Copyright &y& Elsevier]

Abstract: The Ulan Buh Desert (UBD), in southwestern Inner Mongolia, is one of the main dune fields and dust source areas in northern China. In the southern UBD, consisting primarily of high pyramidal and complex sand dunes, the process of desert evolution remains unclear due to a lack of depositional records and adequate age controls. In this study, we present the stratigraphic record of a 120.5m deep core (WL12ZK-1) collected in this sandy desert region. A 22.6m thick deposit of lacustrine clay/silty clay bracketed between 37m (top) and 54.7m (bottom) thick layers of eolian sand, provides evidence of a desert–lake–desert sequence in the southern UBD. Quartz Optical Stimulated Luminescence (OSL) and K-feldspar multi-elevated-temperature post-IR IRSL (Met-pIRIR) dating technologies were employed to provide a chronology for this sequence. Internal checks of the quartz OSL dating indicate that the quartz single-aliquot regenerative-dose protocol is appropriate for equivalent dose determination and that the quartz ages younger than 60ka are acceptable. The reliability of the K-feldspar ages is confirmed by both internal checks and an age-temperature plot. The combined stratigraphy and chronology indicate a sand desert landscape developed in the southern UBD at least ~232ka ago, and that a paleolake was present beginning sometime before ~155ka and lasting until ~87ka, with several possible lake level fluctuations. Desert landforms developed synchronously in the southern and northern UBD after the paleolake regressed. A combination of tectonic activity and climate change may be responsible for this sequence. [Copyright &y& Elsevier]

Abstract: Located in southwestern Inner Mongolia in northern China, the Ulan Buh Desert (UBD) has evolved significantly during the Holocene. The northern desert is adjacent to Hetao Plain, an important agriculture area since the Han Dynasty (~200B.C.). A series of aeolian sand–lacustrine sequences from the desert were measured and dated by using differential global positioning system (DGPS) and optically stimulated luminescence (OSL) technologies respectively. These lacustrine remains with similar deposit sequences have almost identical elevations and depositional ages, indicating that they belonged to a unified paleolake. In addition, the Holocene paleolake/desert evolution process in UBD is established. Aeolian activity prevailed before ~8.3ka, and a unified Ulan Buh Paleolake containing the modern Jilantai Salt Lake covered the northern desert during 7.8–7.1ka ago. The paleolake shrank and broke apart after 6.5ka ago. Thereafter, the paleolake evolved into the modern UBD and Jilantai Salt Lake. The study of one sand–lacustrine section at the southern edge of Hetao Plain shows that the Tushenze Paleolake had a similar evolution process to Ulan Buh Paleolake, though they may not be connected to each other, as suggested by the elevation difference. The Ulan Buh desert–lake evolution was likely due to the climate changes in the monsoon-influenced region during the early–middle Holocene. [Copyright &y& Elsevier]

The dynamic change of soil water as a function of leaf area index and the soil water deficit value, prerequisites for assuring the survival of plants, were simulated. We established a dynamic soil water model based on a theory of water balance, the characteristics of the environment, and the physiological ecology of the plants in the Ulan Buh Desert, northwestern China. We estimated the soil water carrying capacity of the vegetation in our study area of the desert. The results showed that the proportion of soil evaporation in the total amount of precipitation was greater than 60% in the wandering and semifixed sands and 44.8%in the fixed sand. When the leaf area index was less than 1.7 m2/m2, the soil water deficit was maintained at a low level, but when the leaf area index continued to increase, the soil water deficit increased rapidly as well. In consequence, we come to the conclusion that the leaf area index of the soil water carrying capacity of the vegetation is 1.7 m2/m2 in our study area. [ABSTRACT FROM AUTHOR]

Extensive investigations and studies on topography, sedimentary and chronology show new evidence for the formation and evolution of the Ulan Buh desert during early Holocene. Evidence on clay-sand strata and plant roots under interdune lowlands, lake shorelines covered by plenty of Corbicula largillierti and large amounts of dry salt lakes in the central region of the desert prove that many megalakes existed in the hinterland of Ulan Buh desert. Several OSL samples collected from Aeolian sands overlying lacustrine sediments in profiles around Jilantai Salt Lake and interdune lowlands in the southern Ulan Buh desert suggest that the desert began around 7 ka B.P.. The formation of Ulan Buh desert may have resulted from the shrinking of Jilantai megalakes and sands blown from exposed loose sediments. [ABSTRACT FROM AUTHOR]