Subjects: Geosciences >> Geology submitted time 2024-05-15 Cooperative journals: 《干旱区科学》
Abstract： Human activities lead to the accumulation of a large amount of nitrogen and phosphorus in sediments in rivers. Simultaneously, nitrogen and phosphorus can be affected by environment and re-enter the upper water body, causing secondary pollution of the river water. In this study, laboratory simulation experiments were conducted initially to investigate the release of nitrogen and phosphorus from river sediments in Urumqi City and the surrounding areas in Xinjiang Uygur Autonomous Region of China and determine the factors that influence their release. The results of this study showed significant short-term differences in nitrogen and phosphorus release characteristics from sediments at different sampling points. The proposed secondary kinetics model (i.e., pseudo-second-order kinetics model) better fitted the release process of sediment nitrogen and phosphorus. The release of nitrogen and phosphorus from sediments is a complex process driven by multiple factors, therefore, we tested the influence of three factors (pH, temperature, and disturbance intensity) on the release of nitrogen and phosphorus from sediments in this study. The most amount of nitrate nitrogen (NO3–-N) was released under neutral conditions, while the most significant release of ammonia nitrogen (NH4+-N) occurred under acidic and alkaline conditions. The release of nitrite nitrogen (NO2–-N) was less affected by pH. The dissolved total phosphorus (DTP) released significantly in the alkaline water environment, while the release of dissolved organic phosphorus (DOP) was more significant in acidic water. The release amount of soluble reactive phosphorus (SRP) increased with an increase in pH. The sediments released nitrogen and phosphorus at higher temperatures, particularly NH4+-N, NO3–-N, and SRP. The highest amount of DOP was released at 15.0°C. An increase in disturbance intensity exacerbated the release of nitrogen and phosphorus from sediments. NH4+-N, DTP, and SRP levels increased linearly with the intensity of disturbance, while NO3–-N and NO2–-N were more stable. This study provides valuable information for protecting and restoring the water environment in arid areas and has significant practical reference value.
Subjects: Geosciences >> Geology submitted time 2024-05-15 Cooperative journals: 《干旱区科学》
Abstract： The southern margin of the Gurbantunggut Desert, China, is characterized by alternating layers of aeolian and alluvial deposits. Investigating the characteristics of arenaceous sediment in this area is of significant importance for understanding the interactive processes of wind and water forces, as well as the provenance of sediment. However, there are relatively few investigations on the characteristics of such sediment at present. In this study, we researched three aeolian-alluvial interactive stratigraphic profiles and different types of surface sediment on the desert-oasis transitional zone of southern margin of the Gurbantunggut Desert. Based on the optically stimulated luminescence (OSL) dating of aeolian sand and analyses of quartz sand grain size and surface micro-texture, we explored the aeolian-alluvial environmental change at southern margin of the desert in Holocene, as well as the provenance of sediment. The results indicated that the grain size characteristics of different types of sediment in the stratigraphic profiles were similar to those of modern dune sand, interdune sand, muddy desert surface soil, and riverbed sand. Their frequency curves were unimodal or bimodal, and cumulative probability curves were two-segment or three-segment, mainly composed of suspension load and saltation load. The quartz sand in the sediment at southern margin of the desert had undergone alternating transformation of various exogenic forces, with short transportation distance and time, and sedimentary environment was relatively humid. In Holocene, southern margin of the desert primarily featured braided river deposits, and during intermittent period of river activity, there were also aeolian deposits such as sand sheet deposits, stabilized dune deposits, and mobile dune deposits. The provenance for Holocene alluvial deposits at southern margin of the desert remains relatively constant, with the debris of the Tianshan Mountains being the primary provenance. Aeolian sand is mainly near-source recharge, which is formed by in situ deposition of fluvial or lacustrine materials in southern margin of the desert transported by wind erosion, and its provenance was still the weathered debris of the Tianshan Mountains. In addition, the sand in interior of the desert may be transported by northwest wind in desert-scale, thus affecting the development of dunes in southern margin of the desert. The results of this study provide a reference for understanding the composition and provenance changes of desert sand in the context of global climate change.
Subjects: Geosciences >> Geology submitted time 2023-09-27 Cooperative journals: 《干旱区地理》
Abstract：覆盖会影响尾矿水、热分布，研究植物纤维毯覆盖对尾矿砂水热分布的影响，对微生物诱导碳酸钙沉淀（Microbial induced calcite precipitation，MICP）技术控制尾矿污染扩散过程中调控水热条件具有实际意义。于2022年夏季在中国科学院新疆生态与地理研究所莫索湾沙漠研究站，布设基于不同材料（黄麻、稻草、椰丝和棕榈）、不同规格（300 gm-2、500 gm-2、700 gm-2和900 gm-2）的植物纤维毯覆盖于尾矿砂的田间模拟试验，通过测定尾矿砂温度、含水率与蒸发量变化，探究植物纤维毯覆盖对尾矿砂水热分布的影响。结果表明：（1） 植物纤维毯覆盖能降低0~20 cm尾矿砂温度、减小日温差及日变化幅度，其中900 gm-2的稻草纤维毯（D9）降温作用最强，日变化幅度最小。（2） 植物纤维毯覆盖能改善0~30 cm尾矿砂的保水性，减少水分蒸发损失。（3） 植物纤维毯覆盖能抑制尾矿砂水分蒸发，试验结束时，相同规格下累积蒸发抑制效率除D9略大于900 gm-2的黄麻纤维毯（H9）外，均表现为：黄麻>稻草>棕榈>椰丝，且均随规格增大而增大，其中D9抑制蒸发效率高达71.3%。（4） 植物纤维毯覆盖干旱区尾矿砂的最佳节水降温方案为D9。综上所述，植物纤维毯覆盖能有效节水降温，研究结果可为干旱区应用MICP技术控制尾矿污染扩散过程中调控水热条件提供理论支撑。
Subjects: Geosciences >> Geology submitted time 2023-09-19 Cooperative journals: 《干旱区地理》
Abstract： The in-depth implementation of aid policy for Xinjiang promotes the efficiency of tourism aid in theregion and improves the high-quality development of its tourism economy. Based on the three-stage data envelopment analysis and Tobit model, this paper measured the factors influencing the efficiency of tourism aid in Xinjiang from 2015 to 2019 and regional differences. The results show that: (1) Environmental factors have a strong influence on tourism aid efficiency. Overall, there is a large margin for improvement in tourism aid efficiency,which is mainly affected by efficiencies of scale. The trend of efficiency value change is pure technical efficiency>scale efficiency>comprehensive efficiency, and a distribution pattern corresponding to high values in thenorth of the region and low values in the south is evident. (2) Regional dummy variables, investment level, percapita educational investment, and attraction of tourism resources significantly improved efficiency. (3) From theperspective of vertical and horizontal compatibility and internal and external suitability, the mechanism influencing the efficiency of tourism aid in Xinjiang is summarized as comprising three periods, three dimensions, andseven aspects, and the changes and evolutionary course of tourism aid in Xinjiang are identified. The results havetheoretical value and a meaningful reference for the macro-adjustment of aid policy in Xinjiang and the optimalallocation of aid resources in the future.
Subjects: Geosciences >> Geology submitted time 2023-09-19 Cooperative journals: 《干旱区地理》
Abstract： In recent years, China has made great progress in the construction and management of national naturereserves such as the Daqingshan National Nature Reserve in Inner Mongolia. However, the associated ecologicalbenefits have not been effectively assessed. The purpose of this study is to assess whether the establishment ofthe Daqingshan National Nature Reserve has contributed to the ecological recovery and improvement of the area.Examining changes in vegetation dynamics can be an effective tool for regional ecological engineering assessment, and this study analyzes such changes using the normalized difference vegetation index (NDVI). Based onthe Google Earth Engine (GEE) cloud platform, the study uses Landsat remote sensing imagery to extract NDVIdata for the nature reserve for the years 1995 to 2020. Spatial and temporal variation in NDVI and variation drivers before and after the establishment of the reserve were analyzed using Pearson correlation, residual analysisand the Lindeman-Merenda-Gold (LMG) model. A decreasing NDVI trend was identified during the 1995—2008period in 69.04% of the studied area, while an increasing NDVI trend was identified during the 2008—2020 period in 94.98% of the studied area. These results indicate that the quality of vegetation in the study area has improved significantly since it became a national nature reserve. Negative impacts from human activities and climatic warming during the 1995—2008 period led to decreases in NDVI in the studied area, with climate warming being the dominant factor. An increase in precipitation and positive impacts from human activities drove increasesin NDVI in the studied area during the 2008—2020 period, with positive human impacts arising from ecologicalenvironmental protection engineering implementation being the main reasons for vegetation recovery during thisperiod. The selection of Landsat remote sensing images and the use of the GEE integrated computing environment enabled the study to obtain vegetation monitoring data over a long time span and at a high spatial resolution. Spatiotemporal variation in vegetation was also more accurately portrayed using the NDVI measure, therebyenriching the technical means for long time-sequence and small region-scale vegetation monitoring. The resultsof this study provide clear evidence of the ecological benefits brought by the establishment of the Daqingshan National Nature Reserve. At the same time, the study provides basic information and technical support for futureecological-environmental management decisions concerning the protected area.
Subjects: Geosciences >> Geology submitted time 2023-08-23 Cooperative journals: 《中国科学院院刊》
Abstract： In order to implement the spirit of General Secretary Xi Jinping’s important speech on strengthening the comprehensive control of desertification and promoting key ecological engineering projects such as the “Three-North Shelterbelt Program”, this study is designated to make concrete efforts to win the battle against desertification on the edge of Hexi Corridor–Taklimakan Desert. The study deeply explores the situation of wind-blown sand flux and prevention tasks in the area. Based on the characteristics of desertified land and wind-blown sand activities on the edge of Hexi Corridor–Taklimakan Desert, the goal is set to effectively prevent the spread of sand and control dust sources. The core focus is on wind prevention, sand resistance, and dust control. The strategic thinking has been formulated for the counterattack battle on the edge of Hexi Corridor–Taklimakan Desert. By systematically analyzing the source areas and paths of “wind, sand, and dust” and targeting the key zones of the desert edge and areas requiring prevention, the key areas and tasks are proposed for desertification control on the edge of the Hexi Corridor–Taklimakan Desert, so as to provide scientific and technological support for winning the battle against desertification on the edge of Hexi Corridor–Taklimakan Desert.
Subjects: Geosciences >> Geology submitted time 2023-08-23 Cooperative journals: 《中国科学院院刊》
Abstract： Over the past 45 years, China has accomplished great achievements in carrying out “Three-North” project. Through largescale vegetation construction, the trends of land desertification, soil salinization, soil erosion and the deterioration of people’s living environment in the “Three-North” areas have been effectively restrained. The people in the desert area are getting rid of poverty and living a healthy life. In the new era, the “Three-North” project has encountered new demands, new challenges and new opportunities, and it is urgent to achieve a significant transform and upgrade and to improve quality and efficiency. This paper summarizes the current situation of the “Three-North” project construction, focuses on the three-north project general planning and the sixth phase planning and the realization path of the “three transformations”, interprets the strategic planning of the “three iconic battles” in the next ten years, and describes the strategic vision of “New Three-North” in the future. A series of specific policy suggestions are put forward such as strengthening institution and capacity building , demonstration zone planning and strengthening scientific and technological support.
Subjects: Geosciences >> Geology submitted time 2023-08-23 Cooperative journals: 《中国科学院院刊》
Abstract： China has made remarkable achievements in combating desertification over the past 70 years. At present, China has entered a new stage of combating desertification while facing many problems such as large desertification land base and high difficulty in combating desertification, and it is more important to meet the national strategic needs of ecological construction, rural revitalization, and the development and utilization of renewable energy in desert, Gobi, and wasteland areas. The strategic choice of combating desertification in China in the new era is overall improvement and key breakthroughs. The core of the strategy is whole-area governance, innovation-driven, and technology integration. The institutional arrangement of preferential policies is to fully implement the “one desert, four mechanisms” (cultivation, prevention, combating, and utilization), make every effort to win the “three iconic battles” of the “Three-North” battle, give priority to the implementation of key demonstration projects, and accelerate the update of policy. A new engine of science and technology will be built to improve the quality and efficiency for combating desertification, draw a bright vision of Chinese-style modernization featuring integration of production, life, and ecology and harmonization between human being and desert, and promote the “Chinese solution” of combating desertification to benefit the whole world.
Subjects: Geosciences >> Geology submitted time 2023-07-28
Abstract： [Objective] Based on the field survey data of Guangxi Shankou National Mangrove Ecological Nature Reserve (hereinafter referred to as Shankou Mangrove Reserve) in 2022, this study selects remote sensing images of six periods from 1987 to 2021 by combining with LUCC and Landscape Pattern Index, and utilizes the object-oriented image classification methodology, which focuses on exploring the process of change of the mangrove wetland in Shankou, Guangxi, and the important influencing factors. [Results] From the perspective of land use: during the past 35 years in the study area, there has been a continuous conversion between land classes, in which the area of cultivated land has been continuously reduced, the area of rice-grass beaches and aquaculture pits have increased in large proportion, the rice-grass beaches have mainly encroached on the former coastal beaches, and the aquaculture pits have mainly been converted from forested land and cultivated land; from the perspective of the landscape: the degree of landscape fragmentation has been continuously increased, the connectivity has been reduced gradually, the shape of the landscape has gradually become more complex, and the land class succession has become more frequent. frequent; Pearson correlation analysis showed that there was a highly significant or significant correlation between land use change and landscape indices of coastal mudflat, mizuna mudflat and aquaculture ponds. [Conclusion] Over the past 35 years, the Yamaguchi Mangrove Reserve has experienced significant land use changes, and invasive species (mikusa beaches) and anthropogenic disturbances (aquaculture pits and ponds) are the main factors affecting the changes of mangrove wetlands in the area, and are also the main causes of the continuous increase in landscape fragmentation; the study adopts a multivariate approach and a multi-dimensional analysis to expose the variability of regional influencing factors, and provides theoretical bases for environmental management and conservation efforts in typical mangrove ecosystems. management and protection of typical mangrove ecosystems by providing theoretical basis.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Geology submitted time 2023-05-17 Cooperative journals: 《干旱区地理》
Abstract： There are more than 54 spots of Danxia landforms in Shaanxi Province, northwest China, which are distributed in the Weibei Uplift and Yishan Slope of the Ordos Basin. In terms of landscape, both positive and negative Danxia landforms have considerable regional differentiation from southwest to northeast of the province. The sandstones of aeolian desert facies with mainly near horizontal or gently inclined Danxia occurrences are the most widely distributed. They are characterized by gully Danxia, wave Danxia, and colored hills, and most of them are in their early stage. The spatial structure type of Danxia landform distribution in Shaanxi Province is condensed, with two high-density areas (Ganquan-Zhidan-Ansai-Fuxian Danxia area and Yulin Jingbian Danxia area), one medium-density area (Zhaojin-Xunyi-Binxian Danxia area), and two low-density areas (Baoji Jiulongshan area and Fugu Lianhuachan area) according to the nearest neighbor index and nuclear density analysis methods. From the viewpoint of the formation mechanism, Mesozoic sedimentation in the Ordos Basin laid the material foundation for the Danxia landform, regional tectonic evolution controls the distribution of positive and negative landforms, and characteristics of joints and fissures are critical in the landscape pattern of the Danxia landform, and water and wind erosions are the leading forces shaping the landscape form of the Danxia landform.
Subjects: Geosciences >> Geology submitted time 2023-03-28 Cooperative journals: 《干旱区研究》
Abstract： As a typical erosion geomorphic unit in the loess areas, gullies continuously erode loess surface under the action of internal and external forces, rainfall, and other factors. There are significant differences in the degree of development of gullies and valleys. Evaluating the development pattern of gullies and valleys can enhance the understanding of their organized, systematic formation and evolution. In addition, comprehensive quantitative indexes can facilitate the understanding of the longitudinal, lateral, and horizontal characteristics of gullies and valleys from multiple perspectives, which can help in the accurate and effective implementation of gully consolidation and loess protection projects, and reduce the constraints on development caused by this fragile geological environment. Evaluating the development of loess valleys is also crucial for exploring the intrinsic mechanism of valley formation, soil erosion, and guiding the ecological restoration of loess areas. In this study, ten quantitative indicators of gully development were selected based on the horizontal spatial, climatic, and pointline characteristics of the gullies, and used to establish an indexed evaluation model of the developmental stages of Dongzhi Loess Plateau gullies based on the efficient multi-factor comprehensive indexing evaluation capacity of the combined entropy-weight rank-sum ratio (RSR) method. Results showed that: (1) The highest weight of 16.08% could be attributed to the normalized vegetation index (NDVI) based on the entropy weighting method, followed by gully density (15.621%), both of which are important indicators for predicting the degree of gully development. (2) The combined entropy weighting RSR method could classify the 82 gullies of Dongzhi Loess Plateau into juvenile, youth, prime, and old age categories, with the percentage of gully area under the prime and old age categories accounting for 88.48% and 88.48%, respectively, while the eastern and northern parts of Dongzhi Loess Plateau exhibited more developed features and strong erosion on the loess surface. (3) The degree of gully development was highly correlated with the underlying palaeomorphology, tectonic geology, and loess thickness. (4) A significant model variance consistency test at P<0.001, with a linear regression R2 fit of 0.986 was observed, which indicated a good performance of the model.
Subjects: Geosciences >> Geology submitted time 2023-03-13 Cooperative journals: 《干旱区研究》
Abstract： Gravel is the product of various hydrological and erosion processes and is a symbol of grassland and soil degradation and ecosystem deterioration. Consequently, gravel also affects various erosion processes. Studying the spatial differentiation of gravel in the Northern Tibetan Plateau is of considerable importance for the restoration of regional ecological environments. In this paper, the size and spatial location of surface gravel were studied, and the spatial heterogeneity was systematically analyzed by Moran’s I index, spatial variogram, geographic detector, and regression analysis. The following results are presented. (1) The global Moran’s I index is 0.481, which shows a significant positive correlation. Meanwhile, the local Moran’s I index shows a high-high gravel accumulation pattern in the eastern part of the study area, low-low in the middle part, and mostly random distribution in the rest of the study area. (2) Gravel spatial heterogeneity is dominated by structural factors. However, some differences are found between the best fitting model of the variogram and the values of characteristic parameters; that is, certain anisotropy characteristics exist. (3) The geographic detector results showed that NDVI and land-use type were the main factors affecting the spatial heterogeneity of gravel size in the study area, while population density, vegetation type, and annual average precipitation were the secondary factors. (4) The results of regression analysis revealed that the optimal scale regression was the best regression model, and NDVI had the largest influence on gravel size, followed by land-use type, annual mean precipitation, and vegetation type.
Subjects: Geosciences >> Geology submitted time 2023-02-02 Cooperative journals: 《干旱区地理》
Abstract：针对宁夏中部干旱带压砂地土壤肥力下降、灰绿板岩矿质元素淋溶释放规律不明等问题，通过室内模拟灰绿板岩冻融干湿循环交替试验，采用修正的Elovich方程、抛物线方程、双常数速率方程、一级动力学方程对各矿质元素的累积释放曲线进行拟合，研究不同粒径板岩在冻融干湿循环作用下的释放动力学特征及最优动力学方程。结果表明：两种粒径灰绿板岩淋溶液中矿质元素淋溶总量随循环次数增大而增大，1 cm粒径灰绿板岩矿质元素累积淋溶总量、淋溶速率在不同循环次数下均大于3 cm粒径。灰绿板岩矿质元素淋溶释放是多因素共同控制的物理、化学过程，其释放过程可大致分为快速反应阶段和反应趋于平衡阶段；压砂地土壤中Ca、K、Mg、P元素的供给量运用修正的Elovich方程预测结果较好，抛物线方程更适用于描述S元素的释放规律。研究结果可为宁夏中部干旱带旱作农田土壤肥力调控提供决策参考。
Subjects: Geosciences >> Geology submitted time 2022-12-20 Cooperative journals: 《干旱区研究》
Abstract：
Habitat quality is an important basis for biodiversity conservation and improvement of the regional ecological environment. With an ecological civilization construction as the background, the spatial- temporal adaptation and driving mechanism of habitat quality is significant to study. Based on land use data in Shaanxi Province in 2000, 2010, and 2020, the characteristics and driving factors in the spatial-temporal adaptations of the quality of habitat in three regions were analyzed using the InVEST model, Theil index model, and geographic detector model. The results showed the following: (1) from 2000 to 2020, the average quality of habitat showed a stable and slightly increasing trend, and the spatial distribution difference was obvious, with the average habitat quality in southern Shaanxi and northern Shaanxi being higher compared to Guanzhong; (2) the difference of habitat quality among the three regions was larger in southern and central Shaanxi compared to northern Shaanxi; (3) the province and the driving factors in the three different regions, vegetation and terrain factors for the habitat quality, and land utilization factor are the main influencing factors of the three major areas affected by the spatial scale. As time goes on, the influence degree gradually strengthens, and the terrain and vegetation factors have different effects on three areas; (4) In addition to single factors, significant impacts on habitat quality changes in the three regions produced cooperative effects on socioeconomic and natural environmental factors.
Subjects: Geosciences >> Geology submitted time 2022-12-20 Cooperative journals: 《干旱区研究》
Abstract：
The Tazhong-38th Corp Desert Highway, currently under construction, extends from the hinterland of Taklamakan Desert to its southeastern edge. Different degrees of wind and sand hazards are distributed along the whole route, posing serious threats to the construction, service, and maintenance of the desert highway. Based on remote sensing image interpretation and wind data analysis, the wind and sand environment characteristics and dune movement rules in different sections of the desert highway were assessed, and a corresponding sand hazard prevention system framework is proposed. Our analysis showed that the prevailing wind directions along the desert highway are NE, ENE, and E, and the frequency of sandy wind increases from 21.7% to 33.8%. The wind direction characteristic develops from sharp bimodal to blunt bimodal, and the wind and sand hazards gradually become more severe: the drift potential along the section ranges from 178.23 to 309.43 VU, the wind energy environment is low to medium, the resultant drift direction is between SW-WSW, and the wind direction variation rate is medium. The annual average dune movement speed is between 3.16 and 6.26 m.a-1 , and there are obvious spatial differences in dune movement speed and direction. The consistency between dune movement direction and the resultant drift direction is poor in some sections. Based on the above environmental characteristics of the desert highway sections, a sand control system for the desert highway, combining blocking and solidification, is proposed. The results of our study have practical application value in the development of prevention and mitigation measures for desert highway sand damage.
Subjects: Geosciences >> Geology submitted time 2022-12-20 Cooperative journals: 《干旱区研究》
Abstract：
With the basis of climate change, nitrogen deposition will have an impact on N2O emissions between the soil and atmosphere in the alpine wetland in the arid region of Northwest China. Taking the alpine wetland at Swan Lake of Bayinbuluke in the middle of Tianshan Mountain as a study area, three nitrogen addition treatments (0, 10, and 20 kg·hm− 2 ·a − 1 ) were set in different water conditions (perennial seeper area, seasonal water area, and perennial dry area). The measurement of N2O was made via static chamber-gas chromatography during the growing season. The relationship between N2O emissions and main environmental factors was explored. The results showed that the following: (1) increased N significantly contributed to N2O emissions under different water conditions in the alpine wetland ecosystem (P < 0.05). Under 0 kg·hm− 2 ·a − 1 treatment, the N2O accumulation showed an uptake from the ecosystem with the growing season. Under 10 and 20 kg·hm− 2 ·a − 1 treatments, the N2O accumulation were emitted. The cumulative N2O emissions increased significantly when nitrogen deposition increased in different water conditions. Increased nitrogen deposition influenced the wetland ecosystem from N2O to sink to the N2O source. (2) nitrogen application significantly affected the rate of N2O emissions from the ecosystem (P < 0.01). In seasonal water area, the relationship between the average N2O emission rate (F), nitrogen addition (N), and soil temperature (T) at a depth of 5 cm was in accordance with the multiple first- order equation (F = −2.763 + 0.209N + 0.151T, R2 = 0.483, P < 0.01). Therefore, N deposition increases N2O emissions in the alpine wetland in the arid region of Northwest China.
Subjects: Geosciences >> Geology submitted time 2022-12-20 Cooperative journals: 《干旱区研究》
Abstract：
Land expansion is facing problems, such as extensive utilization of resources, destruction of ecological environments, and imbalanced regional development. Clarifying the adaptation of the land’s functions is conducive to regional coordinated development. The main contents include evaluating the adaptation of the land’s functions in the Hohhot- Baotou- Erdos region in 1990, 2000, 2010, and 2018, and analyzing its temporal and spatial adaptation characteristics. This paper evaluates the synergy/trade-off relationship of the adaptation of the land’s functions based on the coupled coordination model and the bivariate spatial autocorrelation model. The main conclusions are as follows: first, the land functions in the region of Hohhot-Baotou-Erdos have significant temporal and spatial differentiation characteristics, the production/living functions rise locally, and the spatial distribution takes each municipal district as the high- value center circle/semi- circle distribution pattern with a decreasing outward gradient; second, the overall trend of the ecological function is continuously downward and its spatial agglomeration has the scale-dependent effect of a natural landscape; third, the synergy trade- off relationship of the spatial-temporal differentiation characteristics of the land’s functions are obvious. The coupling coordination degree of land and spatial functions of each flag county has been on the rise from the time sequence adaptation characteristics, and the number of flag counties increases; however, the overall level is low; fourth, the synergy/trade-off relationship of various functions in land space has obvious spatial differentiation characteristics, and this relationship alternately changes with time. The spatial distribution and agglomeration effect of the synergy/trade-off relationship of production and living functions is significant, and the spatial distribution of the this relationship between production/living ecological functions tends to be discrete. Ultimately, the spatial coupling effect of the synergy/trade-off relationship between various functions is at a low level as a whole.
Subjects: Geosciences >> Geology submitted time 2022-12-20 Cooperative journals: 《干旱区研究》
Abstract：
In China, the county is not only an important contributor to carbon emissions and a major carbon sink zone but also a key administrative unit for the implementation of China’s national goals for carbon peak and carbon neutrality. Focusing on Qingcheng County as a typical county in the Loess Plateau, we investigate the carbon emission characteristics and spatiotemporal patterns, to raise awareness of the need for ecological protection of the Yellow River Basin, while achieving high- quality development and green and low carbon transformation. The key results of our study are as follows. (1) The change and structure of county carbon emission in underdeveloped areas have distinct characteristics. Industries below the designated size are the largest source of carbon emissions in Qingcheng County, having a low proportion of industrial carbon emissions but a relatively high proportion of service sector and household carbon emissions. (2) The spatial distribution of carbon emissions in Qingcheng County conforms to the Pareto Principle: 80% of carbon emissions are concentrated in 20% of the region, which is characterized by“overall dispersion and local agglomeration”. The high carbon zones are mainly concentrated in the valley, broken plateau area, and urban area. The medium carbon zones are mainly distributed in the broken plateau area and along the traffic line. Low carbon zones are widely distributed in ridge, hill, and gully areas. (3) The county carbon emissions in the Loess Plateau show clear temporal and spatial pattern differences that are affected by differences in topography. The largest patch index of medium and high carbon zones, such as urban areas, industrial zones, and major towns, increases, the integrity improves, the diversity of carbon sources decreases, and the types tend to be single. The carbon source diversity increases and the aggregation degree decreases in the ecotone between medium carbon zones and low carbon zones, such as transportation lines and residential areas.
Subjects: Geosciences >> Geology submitted time 2022-12-20 Cooperative journals: 《干旱区研究》
Abstract：
Microorganism and enzyme activities in the soil are important biological indicators of soil quality. Farmland soil polluted by heavy metal in Ningyuanbu Town of the Jinchuan District in Gansu Province was the object of this study. To analyze the content of heavy metals (Zn, Pb, Cd, Cr, Cu, Ni, As, Hg), microorganisms (bacteria, fungi, actinomycetes), and enzyme activity (urease, alkaline phosphatase, catalase, dehydrogenase), 26 samples in soil layers of 0-20 cm and 20-40 cm were collected. The results showed that the over-standard rates of Ni, Cu, and As in the soil layer of 0-20 cm were 15.4%, 30.8%, and 38.5%, respectively. The over-standard rates of Ni, Cu, and As in the soil layer of 20-40 cm were 7.7%. There was a negative correlation between Pb, Hg, Ni, Cu, Cd, and As, along with bacteria, urease, alkaline phosphatase, catalase, and dehydrogenase. Cr showed a positive correlation with fungi and actinomycetes. Zn showed a positive correlation with bacteria. Pb, Zn, and Cr were the major factors that dominated soil biological traits, and the contribution rate was 72.4% , 16.2% , and 4.9%, respectively. Catalase activity was sensitive to nickel, copper, cadmium, and arsenic pollution, which can be used as an effective index for the evaluation of soil quality in these areas.
Subjects: Geosciences >> Geology submitted time 2022-12-20 Cooperative journals: 《干旱区研究》
Abstract：
Blowout is an important manifestation of grassland desertification that is a common for a wind erosion landform in sandy grassland and is highly destructive to grassland vegetation. The blowouts that were in the active development stage of HulunBuir grassland were the object of this research, and the surrounding grassland was the control in which the soil moisture was measured in different locations and different depth. The results show the following: (1) Blowouts caused the“crevasse”effect of soil moisture in grassland that lead to a significant decrease in the soil of the surrounding grassland in a range of nearly 20 m. A close proximity to the pit results in lower soil moisture, A“dry zone”was formed in the range of 0-3 m at the edge of the pit, and the soil moisture was reduced by 45.15% compared with the control. (2) Soil moisture of the pit decreased by 44.44%, and no significant difference was observed in the soil moisture between the surrounding sand accumulation area and the lightly overlying sand area compared to the control. (3) There was a great difference in soil moisture of the pit in the soil layers and sand accumulation area. Cv could reach more than 50%. As soil depth increased, the soil moisture increased first and then decreased. (4) The sand accumulation area of blowouts could realize a certain“water storage”effect after the rainy season, the pit and edge zone had a serious“water loss”effect. The soil was extremely dry soil provided conditions for the expansion and morphological development of blowouts.
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