Maowusu Desert Research Articles

Assessing the impact of agriculture, coal mining, and ecological restoration on water sustainability in the Mu Us Sandyland

Balancing water demand for socio–economic development and ecosystem stability presents a challenge for regional sustainable management, especially in drylands. Previous studies have indicated that large–scale ecological restoration projects (ERPs) lead to a decline in terrestrial water storage (TWS) in the Mu Us Sandyland (MUS). However, the effects of other human activities (e.g., cropland reclamation, coal mining) on water resources remain unclear, raising concerns regarding water crisis and human–natural system sustainability. Through the utilization of coal mine location data, we found that the impact of coal mass loss on the Gravity Recovery and Climate Experiment (GRACE) products cannot be ignored in MUS, especially in the coal–rich northeastern part. Combining these data with auxiliary datasets, we observed a significant (p < 0.05) decrease in TWS (−0.85 cm yr−1) and groundwater storage (GWS, −0.95 cm yr−1) in the MUS, with human activities accounting for 79.23 % of TWS and 90.45 % of GWS reductions, primarily due to increased agricultural and industrial water consumption. Agricultural water consumption increased 2.23 times from 2001 to 2020, attributed to enhanced water use intensity (62.6 %) and cropland expansion (37.4 %). Industrial water consumption in Shenmu, a representative coal county, experienced a 4.16–fold rise between 2001 and 2020. Despite these challenges, local governments have alleviated water stress, ensured food security, and increased household income by comprehensive management strategies, such as enhancing water–saving technology and enforcing stringent policies. Previous studies have overestimated the amount of water resources consumed by ERPs. However, ERPs has played a critical role in stabilizing the regional ecological environment and ensuring the region as a vital food and energy supplier. Our findings can guide for socio-economic development and water management policies in similar regions.

An improvement of the Revised Wind Erosion Equation by considering the effect of non-photosynthetic vegetation

Non-photosynthetic vegetation (NPV) can significantly impact the magnitude of wind erosion. However, most wind erosion models did not take NPV into account, which led to large uncertainties in wind erosion simulation. To reduce these uncertainties, the effects of NPV on wind erosion should be considered in wind erosion simulations. Herein, we collected the hyperspectral and fractional coverage (fNPV) data of NPV from the Mu Us Sandy Land (MUSL). Through constructing a model between the normalized difference tillage index (NDTI) and fNPV, the fNPV values in the MUSL from 2014 to 2017 were estimated by Landsat 8-OLI images and were used to improve the combined vegetation factor (COG) in the Revised Wind Erosion Equation (RWEQ) model to improve this model. Then, the improved RWEQ model was employed to simulate the wind erosion process of the MUSL during these years. The results showed that the mean values of the fNPV in the MUSL from 2014 to 2017 were approximately 2.71 times higher than those estimated by NDVI data (MOD13Q1). The improved RWEQ that considering the NPV significantly improved the precision of the simulation results, as validated by measured data. Compared with the wind erosion modulus (WEM) without NPV, the decreased values caused by NPV were 130.48 t/km2/a (annum), 91.79 t/km2/a, 85.51 t/km2/a and 93.76 t/km2/a from 2014 to 2017, respectively, and the rates of decrease in wind erosion in the corresponding year were 26.52 %, 16.9 %, 21.47 % and 31.33 %, respectively. We believe that integrating NPV monitoring technology into wind erosion models could significantly improve the accuracy of wind erosion simulation, and this study provides new insight into wind erosion modelling, which would be of interest to scholars in the fields of wind erosion and dust emission.

Geochemical evidence for changes in provenance and paleoclimate during the Holocene obtained from a fluvial–eolian sequence in the southern Mu Us Desert, north-central China

Identifying the sources and weathering degree of sediments in the northern deserts of China is crucial to understand the evolution of the Asian monsoon system and corresponding induced changes in surface processes. Great progress has been made in the reconstruction of paleoclimate and paleoenvironment from the Early Holocene onwards based on chronostratigraphy and proxies of aeolian sedimentary sequences in the Mu Us Desert (MUD). However, previous studies have given rise to some controversial over the timing of the Holocene optimum period, and there is a scarcity of studies on the sediment provenance evolution of the desert during the Holocene and its internal relationship with the East Asian summer (EASM) and winter (EAWM) monsoons. Here, we provide new elemental geochemical data from a fluvial–aeolian sedimentary sequence in the southern MUD; we then combine these data with other available elemental data and hydroclimatology information to investigate the characteristics of sediment source evolution and their possible connection with the EASM and EAWM on the southern margin of the MUD-desert/loess transition zone since the latter part of the Early-Holocene. The elemental composition and geochemical characteristics of the studied sedimentary sequence differed markedly in the periods before and after 6.4 ka BP, suggesting a change in the source of the sediments across this boundary. From the late Early-Holocene (10.6 cal. ka BP), sediments were dominated by the chemical weathering products of local source material, with a gradual increase in chemical weathering over time, indicating a gradual strengthening of the EASM; the EASM reached its peak Holocene strength at 8.4–6.4 ka BP, accompanied by a moderate level of chemical weathering. After 6.4 ka BP, with the weakening of monsoon precipitation, the EAWM began to strengthen, and long-distance transport of source material from the west and northwest increased; however, chemical weathering of local source material driven by the EASM remained dominant until 4.0 ka BP. After 4.0 ka BP, the EAWM became dominant, and sediments showed strong sedimentary cycles, mainly transported from long-distance sources by aeolian activity, and the MUD became an important sedimentary sink for the northern-central deserts. After 0.7 ka BP, the sediments in the MUD became a mixture of different-age sediments due to river scouring and the transport of pre-existing sediments along the shoreline. Collectively, the elemental geochemical and other proxy data from Holocene sediments on the southern margin of the MUD record an inverse relationship between the EASM and EAWM; these two monsoonal circulations have alternated in their control of the sedimentary source characteristics and geomorphological environmental evolution processes across the southern margin of the MUD during the Holocene.

Seasonal Drought Dynamics and the Time-Lag Effect in the MU Us Sandy Land (China) Under the Lens of Climate Change

Sand prevention and control are the main tasks of desertification control. The MU Us Sandy Land (MUSL), one of China’s four main deserts, frequently experiences droughts and has a very fragile biological environment. Climate change is the main factor leading to drought, and it may result in more serious drought situations in the future. The Temperature Vegetation Dryness Index (TVDI) was established using land surface temperature and normalized difference vegetation index data. In this paper, we investigate spatial and temporal change characteristics, future change trends, and the time-lag effect of TVDI on climate factors at different scales in MUSL from 2001 to 2020 using Sen + Mann–Kendall trend analysis, Hurstexponent, partial correlation analysis, and lag analysis methods. The results show that (1) the overall drought shows a spatial characteristic of gradually alleviating from west to east (TVDI = 0.6). A significant drying trend dominated 38.5% of the pixels in the fall (Z = 1.99), and a highly significant drying trend dominated the rest of the three seasons (Z average = 2.95) and the whole year (Z = 3.47). (2) In the future, dry autumn, winter, and the whole year will be dominated by continuous drying, and spring and summer will mainly change from dry to wet. The main relationships between winter TVDI and temperature (−0.06) and precipitation (−0.07) were negative, while evapotranspiration (0.18) showed a positive correlation. The six land use types in spring, summer, fall, and the whole year were primarily non-significantly positively correlated with temperature and evapotranspiration. (3) At the seasonal scale, the sensitive factors in spring and autumn were opposite, with spring TVDI responding quickly to precipitation (0.3 months) and being less sensitive to temperature (1.8 months) and evapotranspiration (2 months). At the interannual scale, desert land TVDI was most sensitive to precipitation (2.6 months) and least responsive to temperature (3 months).

Effects of Salix psammophila on groundwater recharge in a semiarid area of north China

Study regionThe semiarid Mu Us Sandy Land (MUSL) was selected for this study. It is in the farming‐pastoral ecotone of north China and functions as an eco-environmental barrier. Study focusAfforestation can mitigate desertification and soil erosion by improving hydrologic condition, which is particularly true for semiarid and arid regions. However, little is known about the quantitative response of hydrologic improvement to afforestation level that can be measured by leaf area index (LAI). The objective was to setup and use a physically-based model to quantitatively assess the dynamics of water fluxes from Salix psammophila afforestation in the MUSL. New hydrological insights for the regionAcross the assessment period of 28 April to 3 October 2016, the total transpiration was determined to be about 294.4 mm. As LAI increased, while the transpiration tended to increase and the evaporation to decrease, the evapotranspiration tended to increase with increase of LAI until LAI =2.0 and then plateaued for LAI >2.0. On the other hand, the recharge rate tended to decrease with increase of LAI until LAI =2.0 and then plateaued for LAI >2.0. Overall, the impacts of Salix psammophila afforestation on soil-water replenishment and groundwater recharge would plateau for LAI >2.0, mandating a good balance between solving large-scope eco-environmental problems by Salix psammophila afforestation and sustaining water resources in the long run.

The feasibility of utilizing sifted desert sand (

To deal with the shortage of the raw materials, like cement, gravel, and sand in the construction and building materials (CBM) industry, the feasibility of utilizing the desert sand (DS) was investigated. In this research, the DS sourced from Maowusu desert was applied. As inspired by that the smaller the particles, the more reactive of the powder, the particles smaller than 75 μm (which is called sifted desert sand, SDS) was sieved with its physical properties and chemical compositions being evaluated and compared with the original DS. It showed that compared with DS powder, the SDS particles have much smaller size (median diameter = 52 μm) and smoother surfaces, with lower SiO2 content, and much higher contents of alkaline oxide, Al2O3 and CaO in particular, which indicated a higher activity of the SDS. Then, the SDS was used to partly replace the cement clinker with varying dosages to prepare the paste samples. The results indicated that the compressive strength of the pastes at 3 days, 7 days, and 28 days all follow an order of increasing firstly, then decreasing gradually, with increasing SDS content. Then, analytical calculation was applied to determine the strength of the SDS-cement paste and the values were compared with the experimentally measured values to probe into the role SDS played. Via combination with microstructure examination, it showed that when SDS was introduced, except for the dilution effect and nucleation effect, the chemical effect including that alkaline oxide, like Al2O3 and CaO could dissolve from the SDS and further participate into the hydration also plays a significant role in the strength development of the composite. The micro-morphology that the SDS particles and matrix pastes were chemically bonded with no distinct Interfacial transition zone observed also verified this. These both indicated that SDS could be used as a kind of supplementary cementitious material, rather than merely as a kind of inert admixture. Finally, the space coordination theory was applied to further illustrate the reason why 10 % is the optimal dosage. This research provides an approach of utilizing the DS in CBM industry with a more effective way.

High-northern-latitude forcing modulated fluvial‒aeolian interplay during the Last Glacial Period in the Mu Us Desert, northern central China

Substantial stratigraphic evidence from the Late Quaternary at orbital- and millennial‒scales indicates that the formation and evolution of aeolian‒sand landscapes results from the interaction between regional aeolian and fluvial‒lacustrine activity. In many deserts (sandy lands) across the planet, fluvial‒aeolian interplay at the glacial‒interglacial scale since the Late Quaternary has been responsive to monsoonal precipitation, and linked to atmospheric CO2 and periodic variations in insolation. However, the patterns of fluvial‒aeolian interplay and their relationship with climate change are not always consistent over a given timescale during the Late Pleistocene. The paucity of studies on fluvial‒aeolian interplay in the Mu Us Desert (MUD) during the Last Glacial Period (LGP) hinders our understanding of the relationships between the dynamics of aeolian and fluvial‒lacustrine landscapes and their drivers. Here, based on a comprehensive field survey and stratigraphic dating of a typical fluvial‒aeolian sequence in the MUD, we synthesized the chronology of fluvial‒lacustrine and aeolian strata during the LGP. Our results show that extensive development of a fluvial‒lacustrine environment in the MUD during the LG mainly occurred during the late Last Glacial Maximum (LGMa, 20.1–18.4 ka BP) and Bølling/Allerød interstadial (14.8–12.6 ka BP), while thicker aeolian sands extensively accumulated during the Heinrich Stadial 2, Heinrich Stadial 1, and Younger Dryas periods. However, the development of fluvial‒lacustrine environments showed considerable spatial heterogeneity, mainly occurring on the southern and eastern margins of the desert, while they were extremely rare in the central and western parts of the desert owing to strong wind erosion. Comparisons with other high-resolution geological records from the Asian monsoon region reveal that the fluvial‒aeolian interplay in the MUD during the LGP was highly consistent with the evolution pattern of the East Asian summer monsoon (EASM) on the millennial‒centennial scale, and indicate that the development of fluvial‒lacustrine environments was mainly controlled by an increase in monsoonal precipitation during strengthening of the EASM. Consistency with other broad changes at high latitudes in the Northern Hemisphere suggests that fluvial‒aeolian interplay during the LGP in northern Chinese deserts, as represented by the MUD, was mainly controlled by changes in high-northern-latitude ice volume and the Atlantic Meridional Overturning Circulation.

Dynamics of soil wind erosion in the Mu Us sandy land (in northern China) affected by cropland reclamation from 2000 to 2020

In recent decades, the wind speed displayed an obvious declining trend in northern China. Under this background, large amounts of grassland and sandy land have been reclaimed into cropland in the Mu Us Sandy Land (MUSL), and whether cropland reclamation will cause an increase in wind erosion has aroused widespread concern. Additionally, there are two reclamation patterns including croplands reclaimed by herdsmen and enterprises in this round of cropland reclamation, whether the different reclamation patterns will induce differential wind erosion is also a scientific question. These questions have influenced the policy of cropland reclamation. Consequently, the Revised Wind Erosion Equation (RWEQ) validated by field observations was applied to simulate the wind erosion of the MUSL from 2000 to 2020. Furthermore, by simulating the wind erosion modulus (WEM) under different scenarios, the climatic fluctuations and cropland reclamation effects on the WEM were distinguished. The results showed that the WEMs of the MUSL decreased during the simulated period. Moreover, the average annual WEM of croplands reclaimed by herdsmen was higher than that reclaimed by enterprises by 18.49% and 12.85% during the 2015 phase (during 2013 to 2017) and 2020 phase (during 2018 to 2020), respectively. The average WEM of the newly reclaimed croplands (reclaimed after 2013) increased 42% relative to the old croplands (reclaimed before 2013), but compared with the original land use types, the WEM of newly reclaimed cropland decreased by 134.55 and 158.94 t/km2/a (annum) during the 2015 phase and 2020 phase, respectively. During the fallow period of the cropland reclaimed by enterprises, the WEM was two times as high as that during planting, so corresponding measures to reduce wind erosion during fallow should be implemented. This study resolves the question of whether cropland will lead to an increase in wind erosion and provides valuable information for reclamation in the MUSL.

A Study of the Change in Surface Parameters during the Last Four Decades in the MuUs Desert Based on Remote Sensing Data

As an important part of the Earth’s environmental system, sandy soils are particularly sensitive to changes in the climatic environment. As one of the four major desert regions in China, the MuUs desert has transformed from a desert to an oasis after more than half a century of ecological management. In this paper, we analyzed the spatial and temporal patterns of surface albedo, evapotranspiration, and fraction vegetation cover in the MuUs desert based on the Global Land Surface Satellite (GLASS) product with high spatial and temporal resolution and assessed the relationships between their variability and snow cover, air temperature, and precipitation. It is of great significance to understand the effect of desertification control and climate change after the conversion of land surface types in the MuUs region. The results show that the desertification control in the MuUs area has achieved remarkable results since 1982. The fraction vegetation coverage of the MuUs desert showed a significant increasing trend, with an interannual change rate of 1.32% each decade−1. The surface albedo of MuUs desert decreased significantly. Affected by vegetation and snow cover, it was lower in summer and higher in winter. The evapotranspiration showed a significant upward trend, higher in summer and lower in winter, which is significantly correlated with the changes in surface albedo, air temperature, and vegetation. In addition, the local-scale biophysical effects caused by vegetation change have influenced the climate of the MuUs region, manifested as the increase in precipitation and air temperature. In general, with the support of relevant policies and human construction projects, the overall ecological environment in the MuUs desert is developing in a good way.

Desertification in the Mu Us Sandy Land in China: Response to climate change and human activity from 2000 to 2020

China is a country largely affected by desertification. The main purpose of this article is to analyze interannual and seasonal changes in fractional vegetation cover (FVC) in the Mu Us Sandy Land (MUSL). It uses fused remote sensing data to quantitatively analyze the response of FVC to climate change and human activities. The results showed that desertification in the MUSL had improved over the past 20 years. Grade V desertification decreased from more than 60% in 2000 to about 15% in 2020. In some years, degradation appeared to be affected by climate factors and human activity, especially in the northwestern portion of the study area. The FVC in summer was slightly higher than that in autumn and far higher than recorded in spring and winter. Spatially, the northwestern and central parts of the study area were unstable, with high coefficients of variation. FVC gradually increased from northwest to southeast, and areas with the fastest increase in FVC were concentrated along the eastern and southern edges of the study area. The correlations between FVC and precipitation and dryness were slightly positive, but the correlation between FVC and temperature showed regional differences. The increase of population density is not a key factor limiting the growth of vegetation; the policy of “grazing prohibition, grazing rest, and rotational grazing” has allowed the restoration of vegetation; and afforestation is an effective way to promote the increase in FVC.

Redistribution process of precipitation in ecological restoration activity of Pinus sylvestris var. mongolica in Mu Us Sandy Land, China

Precipitation is the most important water resource in semi-arid regions of China. The redistribution of precipitation among atmospheric water, soil water and groundwater are related to the land surface afforested ecological system. The study took widely replanted Pinus sylvestris var. Mongolica (PSM) in Mu Us Sandy Land (MUSL) as a research object and monitored precipitation, soil moisture, sap flow, and deep soil recharge (DSR) to find out moisture distribution in shallow soil layers. Results showed that the restoration process of PSM in MUSL changed the distribution of precipitation, with part of it infiltrating downward as DSR and part of it being stored in the shallow soil. Consequently, evapotranspiration increased and DSR significantly decreased, resulting in up to 466.9 mm of precipitation returning to the atmosphere through evapotranspiration in 2016. Vegetation increased soil water storage (SWS) capacity, with maximum SWS in PSM plot and bare sandy land (BSL) being 260 mm and 197 mm per unit horizontal area, respectively in 2016. DSR decreased from 54% of precipitation in the BSL plot to 0.2% of precipitation in the PSM plot in 2016. A great portion of infiltrated water was stored in the PSM ecosystem, resulting in a time lag of infiltration to reach the deep soil layer, and the infiltration rate in the BSL plot was 11 times of that in the PSM plot. SWS decreased 16 mm and 7.6 mm per unit horizontal area over a one-year period (from March to October, non-freezing time) in 2017 and 2019, respectively. The PSM annual sap flow was maintained at a relatively constant level of 154 mm/yr. Through in-situ measurement and comparative analysis of the precipitation redistribution of the BSL plot and the PSM plot, we find that PSM can significantly reduce the shallow soil water storage and DSR. However, substantial reduction of shallow soil water storage and DSR is detrimental for the long-term development of PSM forest. Therefore, it is necessary to reduce PSM density to cut the water consumption by PSM per unit area, thus to augment the shallow SWS and DSR, which will be beneficial for the PSM to survive under extreme drought conditions in the future. This study helps us understand the role of precipitation-induced groundwater recharge in the process of vegetation restoration in semi-arid regions and explains the possible causes of PSM forest degradation.

Effects of Different Cropland Reclamation Periods on Soil Particle Size and Nutrients From the Perspective of Wind Erosion in the Mu Us Sandy Land

Land use changes could notably influence the magnitude and distribution of wind erosion. In recent decades, land reclamation flourished in the Mu Us Sandy Land (MUSL) to supplement cultivated lands (CLs) occupied by urbanization. To analyze the effects of land reclamation on wind erosion, the soil texture and soil nutrients in arable and uncultivated lands should be evaluated. In this study, we collected 54 paired soil samples from CLs and nearby uncultivated lands (NULs) in the MUSL considering land use data pertaining to different phases. Then, the soil particle distribution (PSD) and contents of soil organic carbon (SOC) and total nitrogen (TN) were measured in the laboratory. The results indicated that after 1–15 years (Yr) of cultivation, compared to the NULs, particles ranging from 60 to 400 μm obviously decreased. With increasing number of cultivation years, the wind sorting effects accumulated, and the content of erodible particles susceptible to wind erosion decreased. Among the CLs with different cultivation years, new CLs exhibited the highest erodible particle content, and medium CLs exhibited the lowest erodible particle fraction content. The SOC contents in the medium and fine sand groups among the new CLs was significantly influenced by wind erosion, whereas the TN content was primarily controlled by nitrogenous fertilizer application. After cultivation for longer than 40 years, the total SOC and TN contents in the CLs were significantly higher than those in the NULs. Among the CLs, the wind sorting effects and number of cultivation years obviously influenced the SOC content, whereas the TN content in the CLs was mainly influenced by nitrogenous fertilizer utilization. Rapid urbanization of Shaanxi Province, a new round of national ecological policy adjustments and altered wind environments are the main reasons for the development of new CLs, and a superior location and soil physicochemical properties contribute to the occurrence of old CLs. Based on the above analysis, we propose that conservative cultivation is the key to the protection of new CLs from wind erosion hazards.

NDVI-based vegetation dynamics and their responses to climate change and human activities from 1982 to 2020: A case study in the Mu Us Sandy Land, China

Critical ecological restoration and reconstruction information can be presented by distinguishing the vegetation dynamics due to human activities and climate changes and by determining the main driving factors. In this study, the long-term (1982–2020) satellite-derived Normalized Difference Vegetation Index (NDVI) data sets and climatic factors were employed to analyze the spatiotemporal patterns of the vegetation dynamics in Mu Us Sandy Land (MUSL). In addition, this study investigated their links to variations of temperatures (T) and precipitations (P), and the contribution of human activities and climate change to the vegetation dynamics using the residual analysis were investigated. The results revealed a statistically significant overall greening trend in NDVI changes in 1982–2020 at the MUSL regional scale. To be more specific, this greening trend underwent two distinct periods separated by the breakpoint in 2006. The NDVI first slowly increased before 2006, and then the greening trend rose dramatically after 2006. At the pixel scale, pixels exhibiting greening tendencies exceeded browning trends observably. The correlation between the NDVI and P and T was largely positive, indicating that the P and the T could well explain the dynamic vegetation changes. However, the climatic driving factors for the vegetation growth in the MUSL varied at different time scales. On the monthly scale, T was the main climatic driving factor for the vegetation growth, while P dominated at the annual scale. In addition, the residual analysis indicated that human activities accounted for 56.44% of the NDVI change, while climate change accounted for 43.56%, demonstrating that human activities acted as the dominant drive for vegetation changes. As opposed to the above, degradation was attributed to human activities (52.23%) and climate change (47.77%), respectively. These results are expected to deepen the insights into the driving factors of vegetation change and provide theoretical guidance for ecological management and sustainable development in the MUSL.

Quantitative Reconstruction of Precipitation and Lake Areas During Early to Middle Holocene in Mu Us Desert, North China

Paleoclimatic researches have revealed that the East Asian summer monsoon (EASM) strengthened and precipitation increased in north China during the early to middle Holocene. The lacustrine landform and sediment recorded approximately simultaneous Holocene high lake levels. However, relatively few studies have been reported involving the quantitative reconstruction of precipitation and lake areas in the Mu Us Desert (MUD), northwest edge area of the modern EASM. Based on the lacustrine landform, and by using the lake hydrologic model, this study quantitatively reconstructed precipitation and lake areas during the early to middle Holocene in the MUD. The results revealed the following: 1) A total of 127 paleolakes existed in the closed drainage area during the early to middle Holocene. The area of paleolakes was 896.1 km2, which is 2.96 times that of modern lakes. The relative height between the highstand and the modern lake surface is ∼5–9 m. 2) Precipitation during the early to middle Holocene decreased from 550 mm in the southeast to 350 mm in the northwest. The 400 mm isohyet moved 130–170 km to the northwest, roughly coincident with the modern 250 mm isohyet. 3) The relative increase in precipitation was ∼32–60%, and the increase in the west was significantly higher than in the east. The precipitation gradient in much of the MUD was lower than the present. The results show that the monsoon edge area and monsoon rain belt migrated to the northwest during the early to middle Holocene. The MUD was stably dominated by the EASM. Data also showed that the spatio-temporal pattern of the climate during the early to middle Holocene was relatively humid with a decreased precipitation gradient for millennia.

Effects of Climate Change and Human Activities on Aeolian Desertification Reversal in Mu Us Sandy Land, China

The aeolian desertification in Mu Us Sandy Land (MUSL) in northern China have been paid much attention, but the relative contributions of climate change and human activities to desertification dynamics are still not clear. Based on the Landsat MSS, TM, ETM+ and OLI images in 1975, 1990, 1995, 2000, 2005, 2010 and 2015, we developed a database of aeolian desertification land distribution, discussed the spatial and temporal variation of aeolian desertification, and discovered the relative contributions of climate change and human activities to desertification reversal, using the trends of the potential net primary productivity (NPP) and the human-influenced NPP with meteorological data and MODIS NPP products. The results indicated that aeolian desertification developed firstly from 1975 to 2000, with serious and severe aeolian desertification land continually increasing, and then changed into a reversal state from 2000 to 2015, as the serious aeolian desertification land decreased, although the severe, moderate and light aeolian desertification land lightly increased. Human activities were the dominant factor in desertification dynamics in MUSL and had different contributions to aeolian desertification reversal in different periods. This study will improve our understanding of the processes of aeolian desertification.

陕北长城沿线植被恢复与生态系统防风固沙服务模拟分析

PDF HTML阅读 XML下载 导出引用 引用提醒 陕北长城沿线植被恢复与生态系统防风固沙服务模拟分析 DOI: 10.5846/stxb202107272038 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（41771576，42071285）；陕西省2022年重点研发计划项目（2022SF-382）；陕西省自然科学基础研究计划资助项目（2018JM4010） Simulation analysis of vegetation restoration and ecosystem wind prevention and sand fixation service along the Great Wall in Northern Shaanxi Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探究风沙边缘地区植被恢复与生态系统防风固沙服务能力之间的作用机制以及如何保证防风固沙服务的可持续发展，选择毛乌素沙漠边缘地区--陕北长城沿线为研究区。利用Theil-Sen斜率估算、M-K显著性检验、修正风蚀方程（Revised Wind Erosion Equation，RWEQ）和情景分析法，评估分析2000-2018年该地风沙治理工程效果和生态系统防风固沙服务的时空变化，并着重分析在风蚀因子改变的条件下，植被恢复对土壤风蚀和生态系统防风固沙服务能力的影响。结果表明：（1）在2000-2018年风沙治理工程中陕北长城沿线地区植被恢复状况显著改善，表明多年来在风蚀治理工作中取得显著的效果。（2）在实际情景中，随着植被不断的恢复，风蚀发生的危险程度总体在减小，而风蚀因子是导致实际风蚀量显著改变的主要原因。从生态系统防风固沙服务角度出发，在不同年份防风固沙总量变化显著，2005年和2010年防风固沙量达到最小、最大值，分别为4569.18万t和64164.44万t，差异明显，致使2005和2010年防风固沙服务能力也达到历史最低和最高值。（3）通过最小风蚀因子情景模拟间接表明：植被恢复能够遏制风蚀现象的发生。但在最大风蚀因子情景下，风蚀现象依旧明显，而植被所发挥的生态系统防风固沙服务能力越显著。（4）综合上述3种情景，每年潜在风蚀量 > 防风固沙量 > 实际风蚀量，说明在最大危害程度内生态系统防风固沙服务具有明显的效果。通过研究不仅证实植被是实现防风固沙服务功能可持续发展的必要条件，同时恢复植被对风沙区域进一步发展状况与趋势有着至关重要的作用。 Abstract:In order to explore the mechanism between vegetation restoration and the ecosystem service capacity of the wind prevention and sand fixation (WPSF), this study selected the region along the Great Wall of Northern Shanaxi which is in the edge of Maowusu Desert as the study area to ensure the sustainable development of ecosystem WPSF services. By using Theil-Sen slope estimation, M-K significance test, the Revised Wind Erosion Equation (RWEQ) and scenario analysis method, the paper evaluated and analyzed the effects of the implementation of the Sand Dust Control Project and the spatio-temporal change of ecosystem WPSF service in the study area from 2000 to 2018, and focused on the effects of vegetation restoration on soil wind erosion and ecosystem WPSF service capacity under the condition of changing wind erosion factor. The results showed that:(1) the vegetation restoration along the Great Wall of Northern Shanaxi has improved significantly during the period from 2000 to 2018, which indicates that significant effects have been achieved in the Sand Dust Control Project over the years.(2) In the real condition, with the continuous improvement of vegetation restoration from 2000 to 2018, the overall risk of soil wind erosion has been decreasing, and the wind erosion factor is the main reason for the significant change of the actual amount of wind erosion. From the point of view of ecosystem WPSF services, the total amount of WPSF in different years changed significantly. The amount of WPSF reached a minimum of 45.691 million tons in 2005, but a maximum of 641.644 million tons in 2010. As a result, the service capacity of WPSF also reached the lowest and highest levels in 2005 and 2010.(3) Through scenario simulation, it indirectly indicated that vegetation restoration could restrain the occurrence of wind erosion under the condition of the minimum wind erosion factor. However, under the condition of the maximum wind erosion factor, the wind erosion was still serious, and the ecosystem WPSF service ability of vegetation was more significant.(4) Under the three scenarios, the order is the annual potential wind erosion > wind prevention and sand fixation > actual wind erosion, which shows that the ecosystem WPSF service has obvious effect on the maximum disaster risk degree. In a word, the study proves that the vegetation restoration is not only a necessary condition for the sustainable development of ecosystem WPSF service function, but also plays a vital role in the further development of wind-sand region. 参考文献 相似文献 引证文献

Technological Breakthrough for the Afforestation of Populus euphratica in the Mu Us Desert in China

The Mu Us Desert (MUD) is one of the four largest sandy lands in China. On 22 April 2020, the Shaanxi Forestry Bureau announced that the desertification land control rate in Yulin reached 93.24%, which means that the Mu Us Desert was about to “disappear” from the territory of Shaanxi. However, the problem of biological diversity, mostly for Pinus sylvestris and shrubs in the Mu Us Desert, remains serious. In order to consolidate the current forest conservation efforts, Populus euphratica has been considered an ideal candidate since the 1950s. However, the low survival rate and conservation rate of Populus euphratica in the MUD led us to perform further large-scale introduction for over 70 years. In this study, by using root control seedling technology, the survival and the conservation rate of Populus euphratica were increased to more than 90%. This study makes possible the introduction of Populus euphratica in the MUD, and the successful introduction of Populus euphratica will provide a new barrier for forest ecosystem stability in the desertification control project in the Yulin area.

Numerical Analysis on the Sandy Slope Reinforced with Sand Bags

In recent decades, many expressways and railways have been construction in Western China. One of important projects is Menghua Railway as a major energy transportation line. Since most of its Contract I routine is located in Maowusu Desert, it seems the first choice is to utilize the sandy soil to construct the railway subgrade. The sand bag structure is explored as a reinforcement method for as railway sandy subgrade by numerical analysis. The Flac3D is selected as the calculation tool with its GeogridSEL structural element used to simulate the function of geotextile bag. It is assumed the geotextiles remain elastic in the calculation, and the failure occurs at the interface between geotextiles and surrounding soil. The results show that when bagged sand is used, the internal friction angle of sandy soil can be appropriately reduced, or a steeper slope can be used, but the friction angle between bagged sand and geotextile is required to be larger. At the same time, if the internal friction angle of sand is small, in order to obtain a smaller slope, geotextile is required to be subjected to a larger tensile stress.

Metagenomics Reveal Correlations Between Microbial Organisms in Soils and the Health of Populus euphratica

Biological diversity plays an important role in the stability of ecosystems. The Mu Us Desert (MUD), located in Northern China, is an aeolian desert. Although it has been governed by a series of ecological restoration programs, the MUD still has limited biological diversity. Populus euphratica (P. euphratica), a xerophytic plant, has great potential to improve the biological diversity of the MUD. However, the survival rate of P. euphratica in the MUD has been very low. The current study tried to explore the mechanism of the high death rate of P. euphratica in the microbiome perspective. The correlation study between soil community composition and soil properties showed that water-filled pore space (WFPS), pH, EC, AP, NO3–, and NH4+ possess higher potential to change the bacterial community (18%) than the fungal community (9%). Principal coordinate analysis indicated that the composition of both bacteria (Proteobacteria and Bacteroidetes) and fungi (Ascomycota) in the root soil can be increased by P. euphratica. By systematically comparing between the fungal diversity in the root soil around P. euphratica and the pathogenic fungus extract from the pathogenic site of P. euphratica, we found that the high death rate of P. euphratica was associated with specific pathogenic fungus Alternaria alternate and Didymella glomerata. In addition, the microbiome composition analysis indicated that P. euphratica planting could also influence the portions of bacteria community, which also has great potential to lead to future infection. However, as the extraction and separation of bacteria from plants is challenging, the correlation between pathogenic bacteria and the high death rate of P. euphratica was not studied here and could be explored in future work.

Effects of revegetation on climate in the Mu Us Sandy Land of China

The ecological environment in China's arid and semi-arid regions has been improving over the past few decades. Using the Mu Us Sandy Land (MUSL) as a case study, we examine the consequent climate feedbacks and the impacts of revegetation on regional climate by incorporating high-resolution remote-sensing vegetation data into the WRF-Noah model. From 2001 to 2010, although a small portion of the grassland was degraded in MUSL, vegetation overall improved, with green fraction and leaf area index increased and surface albedo decreased. The model simulation suggests a cooling of the near-surface temperature by 0.12–0.32 °C on average and up to >0.5 °C in summer, with a reduction in nighttime minimum of 0.15–0.46 °C and in daytime maximum of <0.13 °C. The cooling is accompanied by a slight increase in 2-m air humidity. The near-surface cooling and wetting are induced by revegetation-enhanced evapotranspiration, but they have insignificant effect on the local precipitation. The results of this study imply that while revegetation has positive effects on the ecological systems in MUSL, it bears the cost of an increase in evapotranspiration of 51 mm per summer, which may exacerbate the water shortages in the region.