The areas used to be covered by shifting sand dunes have been reclaimed rapidly in recent years.However,it is a challenge to reclaim high sand dunes because it is rather costly to level the high dunes to gentle arable...The areas used to be covered by shifting sand dunes have been reclaimed rapidly in recent years.However,it is a challenge to reclaim high sand dunes because it is rather costly to level the high dunes to gentle arable lands.In this study,a wind guide plate was used to change the characteristics of natural wind to level the sand dunes.The use of wind energy could significantly increase the efficiency of dune leveling and decrease the cost.Low wind velocity is a typical characteristic in Ulan Buh Desert of China where the average wind speed is much lower than the threshold velocity for sand movement.The experiment of this study was conducted to accelerate the wind velocity by a wind guide plate to level a sand dune.Results show that the threshold velocity for sand movement is 3.32 m/s at 10 cm above the sand surface in Ulan Buh Desert.A wind guide plate set at an angle less than 50°could significantly increase the wind velocity.The wind velocity could be accelerated up to the threshold velocity for sand movement behind a plate when the plate is at the angles of 20°,25°,35°and 40°.The most significant acceleration of wind velocity appears at 1.5 and 3.0 m behind the plate with an angle of 25°.An obvious wind velocity acceleration zone exists behind the wind guide plate when the angles are at 25°,35°,40°and 45°,with the most obvious zone under the angle of 45°.The results also show that the total amount of sand transferred over the experimental period increased by 6.1%under the effects of wind guide plates compared to the sand moved without wind guide plates.The results of the study will provide theoretical and practical supports for desert management in sand dune areas.展开更多
[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 B...[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 korshinski Kom.was lower than that of the other 9 species;bound water content(V_a) and bound water/free water ratio(V_a/V_s) of Zygophyl um 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(V_a/V_s),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 Zygophyllum 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.,Cal igonum mongolicum Mattei.,and Caragana microphylla Lam.).展开更多
The Ulan Buh Desert is one of the eight deserts in China that provides wind erosion prevention service(i.e.,the ecosystem;vegetation,production,and construction activities that promote sand fixation).It is significant...The Ulan Buh Desert is one of the eight deserts in China that provides wind erosion prevention service(i.e.,the ecosystem;vegetation,production,and construction activities that promote sand fixation).It is significant for the construction of the national ecological barrier,and the protection of the ecological security in the Yellow River and North China.In this study,we selected two representative years(2008 and 2018)and quantified wind erosion prevention service from the Ulan Buh Desert using the RWEQ model.Meanwhile,the HYSPLIT model was used to simulate the spatial flow process from the service supply area to the beneficiary area and to determine its scope.The specific dust reduction amount in the beneficiary area was then calculated.The energy and the time-space relation of wind erosion prevention service in the areas that receive benefits from Ulan Buh Desert were compared before and after implementing environmental restoration measures.The results showed that:(1)the total amount of wind erosion prevention in the Ulan Buh Desert in 2018 was 2.12×10^(10)kg,which was 5.17 times higher than that in 2008;(2)in 2018,the distribution density of the flow path of wind erosion prevention service was lower than that in 2008,and the flow paths in each year were concentrated in the beneficiary areas with the path distribution frequency of less than 10%;(3)the total dust reduction in the downwind area of the Ulan Buh Desert in 2018 was higher than that in 2008,totaling 15.54 million tons.Inner Mongolia Autonomous Region and Shanxi Province had the most significant amount of dust reduction.展开更多
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 pr...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.展开更多
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 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 naturalhuman 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, the 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%.展开更多
GPR reflecting sections and core profiles revealed that sand dunes of the northern Ulan Buh Desert are overlying shallow lacustrine or palustrine sediments. Optical dating results of sediments from three core profiles...GPR reflecting sections and core profiles revealed that sand dunes of the northern Ulan Buh Desert are overlying shallow lacustrine or palustrine sediments. Optical dating results of sediments from three core profiles indicate that the area of the northern Ulan Buh Desert was still covered by the shallow lake or marsh during 8.4-6.4 ka, and eolian sand started to accumulate since around 2 ka. Such a result supports the idea that the present desert landform of the northern Ulan Buh Desert started to form since 2 ka, which was likely a response to the desertification caused by ruin of the Han Dynasty and the large-scale abandonment of farming of the Han nationality. Our research results are consistent with the previous archaeological studies, and support the idea that the Ulan Buh Desert is composed of two parts with different histories, i.e., the old southern Ulan Buh Desert and the young northern Ulan Buh Desert.展开更多
基金supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2015BAC06B00)the Natural Science Foundation of the Inner Mongolia Autonomous Region of China(2014ZD03)
文摘The areas used to be covered by shifting sand dunes have been reclaimed rapidly in recent years.However,it is a challenge to reclaim high sand dunes because it is rather costly to level the high dunes to gentle arable lands.In this study,a wind guide plate was used to change the characteristics of natural wind to level the sand dunes.The use of wind energy could significantly increase the efficiency of dune leveling and decrease the cost.Low wind velocity is a typical characteristic in Ulan Buh Desert of China where the average wind speed is much lower than the threshold velocity for sand movement.The experiment of this study was conducted to accelerate the wind velocity by a wind guide plate to level a sand dune.Results show that the threshold velocity for sand movement is 3.32 m/s at 10 cm above the sand surface in Ulan Buh Desert.A wind guide plate set at an angle less than 50°could significantly increase the wind velocity.The wind velocity could be accelerated up to the threshold velocity for sand movement behind a plate when the plate is at the angles of 20°,25°,35°and 40°.The most significant acceleration of wind velocity appears at 1.5 and 3.0 m behind the plate with an angle of 25°.An obvious wind velocity acceleration zone exists behind the wind guide plate when the angles are at 25°,35°,40°and 45°,with the most obvious zone under the angle of 45°.The results also show that the total amount of sand transferred over the experimental period increased by 6.1%under the effects of wind guide plates compared to the sand moved without wind guide plates.The results of the study will provide theoretical and practical supports for desert management in sand dune areas.
基金Sponsored by Scientific Research Program of National Forestry Public Welfare Trade(201504710)
文摘[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 korshinski Kom.was lower than that of the other 9 species;bound water content(V_a) and bound water/free water ratio(V_a/V_s) of Zygophyl um 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(V_a/V_s),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 Zygophyllum 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.,Cal igonum mongolicum Mattei.,and Caragana microphylla Lam.).
基金This research was funded by the National Key Research and De-velopment Program(Grant No.2019YFC0507600/2019YFC0507601)the National Natural Science Foundation of China(Grant No.41671080).
文摘The Ulan Buh Desert is one of the eight deserts in China that provides wind erosion prevention service(i.e.,the ecosystem;vegetation,production,and construction activities that promote sand fixation).It is significant for the construction of the national ecological barrier,and the protection of the ecological security in the Yellow River and North China.In this study,we selected two representative years(2008 and 2018)and quantified wind erosion prevention service from the Ulan Buh Desert using the RWEQ model.Meanwhile,the HYSPLIT model was used to simulate the spatial flow process from the service supply area to the beneficiary area and to determine its scope.The specific dust reduction amount in the beneficiary area was then calculated.The energy and the time-space relation of wind erosion prevention service in the areas that receive benefits from Ulan Buh Desert were compared before and after implementing environmental restoration measures.The results showed that:(1)the total amount of wind erosion prevention in the Ulan Buh Desert in 2018 was 2.12×10^(10)kg,which was 5.17 times higher than that in 2008;(2)in 2018,the distribution density of the flow path of wind erosion prevention service was lower than that in 2008,and the flow paths in each year were concentrated in the beneficiary areas with the path distribution frequency of less than 10%;(3)the total dust reduction in the downwind area of the Ulan Buh Desert in 2018 was higher than that in 2008,totaling 15.54 million tons.Inner Mongolia Autonomous Region and Shanxi Province had the most significant amount of dust reduction.
基金supported by the State Public Forestry Special Project of Aeolian Sand Industrialization Utilization and Vegetation Restoration,China(201204205)
文摘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.
文摘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 naturalhuman 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, the 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%.
基金supported by the Innovative Research Team Project of National Natural Science Foundation of China (Grant No.40721061)National Natural Science Foundation of China (Grant Nos. 40502016,40972116)the Fundamental Research Funds for the Central Universities (Grant No.LZUJBKY-2009-68)
文摘GPR reflecting sections and core profiles revealed that sand dunes of the northern Ulan Buh Desert are overlying shallow lacustrine or palustrine sediments. Optical dating results of sediments from three core profiles indicate that the area of the northern Ulan Buh Desert was still covered by the shallow lake or marsh during 8.4-6.4 ka, and eolian sand started to accumulate since around 2 ka. Such a result supports the idea that the present desert landform of the northern Ulan Buh Desert started to form since 2 ka, which was likely a response to the desertification caused by ruin of the Han Dynasty and the large-scale abandonment of farming of the Han nationality. Our research results are consistent with the previous archaeological studies, and support the idea that the Ulan Buh Desert is composed of two parts with different histories, i.e., the old southern Ulan Buh Desert and the young northern Ulan Buh Desert.
