Desertification In Region Research Articles

Hydrogeochemical Response of Cave Drips to Precipitation during Rainfall in a Karst Desertification Region: A Case Study of Shijiangjun Cave, South China

Exploring the hydrogeochemistry of cave drip water and its response to precipitation events in karst rocky desertification regions is of great significance to the paleoenvironment reconstruction of the karst desertification process using speleothem. We selected three perennial drip sites in the Shijiangjun Cave, located in Guizhou Province, Southwest China, and carried out high-frequency monitoring and sampling during two rainfalls from 22 to 25 May 2016. The major hydrogeochemical parameters of drip water and their relationships with karst desertification were analyzed. The results show that the hydrogeochemistry of the drip water in the Shijiangjun Cave, characterized by HCO3-Ca·Mg, was dominated by the dissolution of calcareous dolomite. The three drip sites were classified into the delayed response type (W1) and the rapid response type (W2 and W3) based on the response speed of the drip water indicators to precipitation, which were highly influenced by the piston effect and precipitation dilution, respectively. Furthermore, the response sensitivity of the drip water indicators to precipitation was constrained by the desertification degree in the rainy season, specifically, the faster response appeared in the higher desertification degree area. It is essential to select appropriate drip sites and establish an applicable indicator system for the evolutional history reconstruction of karst desertification using speleothems.

Relationship between species distribution of sandy alpine grasslands and microtopography in the source regions of Yangtze river

Dynamic of sandy alpine grasslands affect the progress and reversal of desertification in source regions of the Yangtse Rivers. To understand geomorphic driving mechanism of species distribution pattern, we examined the species compositions and delineated the most important landform factors influencing species distribution of sandy alpine grassland using two-way indicator species analysis (TWINSPAN), detrended correspondence analysis (DCA), and canonical correspondence analysis (CCA). Field survey were conducted in summer of 2016 using stratified random methods in hilly sloped lands, floodplains, foothills, and valley land of study region. In total, 29 plant species grouped into 27 genera and 16 families were identified. Leymus secalinus, Elymus dahuricus and Corispermum declinatum are the dominant species of sandy alpine grassland communities in different microtopography. The present vegetation reflected xerosere character, which indicated that desertification of alpine grassland is in progress. Standard frequency distribution of species varied with different microtopography, the proportion of dominant species was generally lower than rare species, and the vegetation community was in a highly successional stage. Seven groups were distinguished through TWINSPAN, distribution of which in the DCA ordination graph showed species with similar ecotype is clustered together. The results of the CCA ordination revealed that slope and aspect are the dominant factors among microtopography determining the species distribution of sandy alpine grassland.

An evaluation of the use of IMERG products for representing drought in a typical rocky karst region experiencing rocky desertification in Guangxi, China

ABSTRACT Droughts are very common and threatening disasters in regions where groundwater storage is difficult. High-resolution satellite estimations such as the Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) provide a new solution for drought monitoring in areas with this special terrain. In this study, the pre-evaluation of products is conducted before drought monitoring, then based on the Standardized Precipitation Index (SPI), the application in drought presentation is evaluated over Guangxi, a Chinese province where the karst areas are being eroded by rocky desertification. The main results are as follows: (1) The monthly estimating by IMERG products is reliable, and the best performance for daily scale appears in regions with rich rainfall and severe rocky desertification, while high errors occur in the same place. (2) IMERG products can be an alternative to gauge-based data in drought monitoring over karst rocky desertification regions like Guangxi, where multiple droughts happened from 2000 to 2017. The SPI of IMERG_F has the best spatial consistency, and better results are presented over humid rocky desertification regions.

Environmental Audit to Limit the Expansion of Desertification in different Regions of Iraq

This paper deals the cognitive foundations of environmental auditing, in addition to explaining the impact of environmental audit procedures on the development and improvement of forests to overcome the problem of receding herbal cover and the expansion of desertification phenomenon. The aim is to clarify the cognitive bases of environmental auditing and environmental audit procedures to reduce the phenomenon of desertification, which contributes to stopping environmental deterioration. The research relied on the descriptive analytical method to track and examine its material, in addition to the statistical method and analysis of the time period (2006-2020). The proposal of the audit matrix and the identification of risks from three criteria for the purpose of evaluating the risks facing the sustainable management of forests in the Republic of Iraq and through the results of the risk evaluation according to the standards three requires working to avoid the frequent reality of these risks in accordance to these criteria in applying environmental audit of its negative impact within the investment budget. In addition to this matter, the development of the necessary plans for the tasks to complete the implementation of green belts projects, which can become environmental audit based on the necessary allocations to complete and sustain green belts.

A novel approach on the delineation of a multipurpose energy-greenbelt to produce biofuel and combat desertification in arid regions

Jatropha curcas L. (JCL) is one of the most prominent energy crops due to its superior agronomical traits, where it can grow in non-arable lands and harsh climates with minimal water requirements. A significant number of studies were published on the utilisation of JCL for biofuel production, whereas there are no studies on its use in greenbelt (GB) or windbreak technologies reported thus far. Meanwhile, a few approaches on the delineation of greenbelts to fight desertification in the arid regions exist in literature. This study presents a novel approach to delineate a multipurpose energy-greenbelt using JCL crop for biofuel production, as well as to preserve the soil and enhance air quality, thereby helping to combat desertification and sand-dust storms (SDS). The methodology is demonstrated using a case study in the state of Qatar for the diversification of its renewable energy resources. Moreover, Qatar is also suffering from land degradation due to erosion factors and desert creep. A multi-dimensional approach is proposed for this purpose using satellite and meteorological data to initially select the optimal plantation sites that potentially contribute to the highest possible biofuel yield. The spatial analysis was carried out using the analytical hierarchy process (AHP) technique for multi-criteria decision making in the geographic information system (ArcGIS). In addition, the Landsat and MODIS satellite imagery were utilised in combination with historical records from the weather stations to evaluate the patterns of SDS, land degradation and urban expansion, to best define optimal GB pathway. COMSOL Multiphysics software was subsequently employed to evaluate the performance of Jatropha-GB and determine its optimal density. The different solutions for GB delineation spans 166.6–227.8 km length and (6 × 6 m) of field density. It is expected that the economic and environmental benefits from the derived GB configuration include: (a) protection of up to 87% of Qatar farms against further deterioration; (b) yield of up to 36 M gallon of green liquid fuels; (c) capture of 0.33 M tonnes of CO2 per 1 km GB-depth annually; and (d) provide a better air quality for around 95% of the Qatar population.

Evaluation of ecological quality in southeast Chongqing based on modified remote sensing ecological index

Rocky desertification is a serious ecological and environmental problem in Southwest China. Quickly and scientifically reveal the distribution and changes of ecological environment quality in rocky desertification areas, which is of great significance to rocky desertification restoration, ecological environment governance and sustainable development. Based on the remote sensing ecological index (RSEI), in addition to greenness, humidity, dryness, and heat, combined with the degree of rocky desertification, this study used the principal component analysis (PCA) method to construct a modified remote sensing ecological index (MRSEI). Then, the temporal and spatial variation characteristics and imaging factors of the ecological environment quality in the typical rocky desertification region of southeastern Chongqing from 2001 to 2021 were explored. The results revealed that the greenness and humidity indicators had a positive effect on the ecological quality, while the indicators of dryness, heat and rocky desertification had the opposite impact. From 2001 to 2021, the ecological environment quality in southeastern Chongqing showed a trend of gradual improvement, and the improvement area accounted for about 70% of the total area. The elevation, slope, monthly average precipitation, and land use pattern were the main factors influencing the quality of the ecological environment in the region.

An integrated approach for the assessment and monitoring of land degradation and desertification in semi-arid regions using physico-chemical and geospatial modeling techniques.

Land degradation (LD) and desertification are serious ecological, environmental, and social-economic threats in the world, and there is a demanding need to develop accountable and reproducible techniques to assess them at different scales. This study assesses LD and desertification with the help of remote sensing (RS) and geographical information system (GIS) in the study region for the period past 29 years, i.e., from 1990 to 2019. The severity of LD and desertification was assessed quantitatively by collecting twelve soil samples in the study region and analyzing the eleven soil physico-chemical parameters and these values have made correlated with digital number (DN) values with LANDSAT 8 OLI/TIRS satellite image. The land cover analysis of LANDSAT imagery revealed that the water body slightly increased from 0.29% in 1990 to 0.46% in 2019, and built-up-land increased from 2.87% in 1990 to 5.31% in 2019. Vegetation decreased from 52.03% in 1990 to 28.57%. Fallow land, degraded land, and desertified lands increased at alarming rates, respectively 13.71% to 26.35, 18.57% to 22.31%, and 12.53% to 17.00%. It is also established that the multi-temporal analysis of change detection data can provide a sophisticated measure of ecosystem health and variation, and that, over the last 29 years, considerable progress has been made in the respective research.

The Evolution of Desertification Control and Restoration Technology in Typical Ecologically Vulnerable Regions

Global economic development and increasing human activities have brought great challenges to fragile ecosystems. In order to avoid, reduce, and reverse desertification, Chinese and foreign scientists and ecological governance institutions have developed a series of ecological restoration technologies (ERTs) and models in the past few decades. These technologies can improve residents' livelihoods, strengthen disaster resilience, and launch a comprehensive review of degraded ecosystems in desertification regions. However, some studies and practices have limited the selection and promotion of good technologies and the assessments of these technologies, resulting in the waste and loss of funds and manpower. The objective of this study is to identify desertification control and restoration technologies and models, summarize the evolutionary features and trends of these technologies under different natural conditions, and evaluate the various ERTs that are now available. The data sources of this study include the databases of international organizations, CNKI, related literature and reports, and questionnaires from institutions and experts. First, the three stages of ERTs evolution were summarized, and the key events and social-economic developments were identified as the driving forces of evolution. Then, the four categories of ERTs were identified as biological, engineering, agricultural, and management ERTs. Finally, the key ERTs were evaluated in the five dimensions of the degree of difficulty, the degree of maturity, effectiveness, suitability, and potential for transfer. The management ERTs scores for the degree of difficulty, the degree of maturity, and potential for transfer are higher. This study provides a reference for adapting to local conditions, the comprehensive management, rational development, and utilization of dryland resources, improving the application of ecological technologies, and promoting the export and import of the excellent technologies.

Effect of Cultivated Pastures on Soil Bacterial Communities in the Karst Rocky Desertification Area.

Soil bacteria play an important role in regulating the process of vegetation restoration in karst ecosystems. However, the effects of vegetation restoration for different cultivated pastures on soil bacterial communities in the karst rocky desertification regions remain unclear. Therefore, we hypothesized that mixed pasture is the most effective for soil bacterial communities among different vegetation restorations. In this study, we systematically studied the soil properties and soil bacterial communities in four vegetation restoration modes [i.e., Dactylis glomerata pasture (DG), Lolium perenne pasture (LP), Lolium perenne + Trifolium repens mixed pasture (LT), and natural grassland (NG)] by using 16S rDNA Illumina sequencing, combined with six soil indicators and data models. We found that the vegetation restoration of cultivated pastures can improve the soil nutrient content compared with the natural grassland, especially LT treatment. LT treatment significantly increased the MBC content and Shannon index. The vegetation restoration of cultivated pastures significantly increased the relative abundance of Proteobacteria, but LT treatment significantly decreased the relative abundance of Acidobacteria. Soil pH and MBC significantly correlated with the alpha diversity of soil bacterial. Soil pH and SOC were the main factors that can affect the soil bacterial community. FAPROTAX analysis showed LT treatment significantly decreased the relative abundance of aerobic chemoheterotrophs. The results showed that the bacterial communities were highly beneficial to soil restoration in the LT treatment, and it confirmed our hypothesis. This finding provides a scientific reference for the restoration of degraded ecosystems in karst rocky desertification areas.

Geo-environmental monitoring and assessment of land degradation and desertification in the semi-arid regions using Landsat 8 OLI / TIRS, LST, and NDVI approach

This research aims to find a relation between measured Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) for assessing land degradation and desertification in semi-arid regions using LANDSAT 8. In the twenty-first century, soil loss has been a serious environmental problem due to anthropogenic pressure and climate change. Monitoring and assessing land degradation vulnerability is becoming increasingly important for sustainable land resource management, especially in semi-arid ecosystems. The purpose of this research is to retrieve the LST and examine the relationship between LST and NDVI, in addition to LST and Landsat 8 bands. The association between LST and Landsat 8 bands is found to be positive, as well as the regression coefficient from NDVI to LST is also found to be strong Positive. The resultant of the NDVI is further classified into five categories based on the pixel values, and they are reclassified into five categories for land cover assessment, they are namely waterbodies, degraded lands, desertified lands, vegetation, and built-up lands. The results reveal that the desertified lands are occupying an area of 13.62%, degraded lands occupy 48.91%, built-up lands occupy 8.39%, vegetation lands occupy 27.34%, and water bodies occupy 1.71% in the study region. These research findings can be used to optimize the technique for future research in the field of degradation assessment, thermal comfort zone assessment, and sustainable agricultural growth.

Studies on Hydrological Processes on Karst Slopes for Control of Soil and Water Loss

Soil and water loss in karst areas seriously restricts the sustainable development of karst ecosystems, the economy and society in southwest China, which has been a concern of, and studied by, many scholars in China and abroad. Soil and water loss has a great influence on the evolution of rocky desertification, groundwater quality, drought and flood disasters in karst regions. This paper aimed to provide a review of studies of slope hydrological processes in soil and water loss. In this paper, 322 related articles retrieved from the Web of Science database and CNKI database were systematically reviewed. Firstly, a quantitative study was conducted to analyze the annual number, countries and research progress of the published literature. Secondly, the main progress and achievements of slope hydrology and soil erosion control technology were classified and summarized according to theoretical research, mechanism research, technology research and technical demonstration. Finally, the key problems and future research prospects are put forward, starting with the existing technology, in order to find more suitable soil and water loss control measures in karst regions and achieve economic and ecological benefits.

Consistency Analysis and Accuracy Assessment of Three Global Ten-Meter Land Cover Products in Rocky Desertification Region—A Case Study of Southwest China

Rocky desertification is one of the most critical ecological and environmental problems in areas underlain by carbonate rocks globally. Land cover and land use in the region affects large-scale ecosystem processes on a global scale, and many Earth system models rely on accurate land cover information. Therefore, it is important to evaluate current global land cover products and to understand the differences between them, and the findings of these studies can provide guidance to different researchers when using or making land cover products. Whereas there are many studies on the assessment of coarser resolution land cover products, there are few studies on the assessment of higher resolution land cover products (10 m). In order to provide guidance for users of 10 m data, this paper uses the rock deserted southwest region of China as the experimental area. We analyzed the consistency and accuracy of the FROM-GLC, ESA WorldCover 10 and ESRI products using spatial pattern consistency, absolute accuracy assessment of three validation samples, and analyzed their intrinsic relationships among classification systems, classification methods, and validation samples. The results show that (1) the overall accuracy of the FROM-GLC product is the highest, ranging from 49.47 to 62.42%; followed by the overall accuracy of the ESA product, ranging from 45.13 to 64.50%; and the overall accuracy of the ESRI product is the lowest, between 39.03 and 61.94%. (2) The consistency between FROM-GLC and ESA is higher than the consistency between other products, with an area correlation coefficient of 0.94. Analysis of the spatial consistency of the three products shows that the proportion of perfectly consistent areas is low at 44.89%, mainly in areas with low surface heterogeneity and more homogeneous cover types. (3) Across the study area, the main land cover types such as forest and water bodies were the most consistent across the three product species, while the grassland, shrubland, and bareland were lower. All products showed high accuracy in homogeneous areas, with local accuracy varied in other areas, especially at high altitudes in the central and western regions. Therefore, land cover users cannot use these products directly when conducting relevant studies in rocky desertification areas, as their use may introduce serious errors.

The Stem Sap Flow and Water Sources for Tamarix ramosissima in an Artificial Shelterbelt With a Deep Groundwater Table in Northwest China.

The shelterbelt forest between oases and the desert plays a vital role in preventing aeolian disasters and desertification in arid regions of northwest China. Tamarix ramosissima (T. ramosissima), a typical perennial and native xerophyte shrub in Northwest China, grows naturally and is widely used in building artificial shelterbelt forests. The balance between water consumption and the availability of water determines the survival and growth of T. ramosissima. How T. ramosissima copes with extremely low rainfall and a deep groundwater table remains unknown. To answer this, the transpiration and the water sources of T. ramosissima were investigated by the heat balance and oxygen isotopic analysis method, respectively. Our results show that the daily T. ramosissima stem sap flow (SSF) was positively correlated with air temperature (Ta), photosynthetically active radiation (PAR), and the vapor pressure deficit (VPD). We found no significant relationship between the daily SSF and soil moisture in shallow (0–40 cm) and middle (40–160 cm) soil layers. Oxygen isotope results showed that T. ramosissima mainly sources (>90%) water from deep soil moisture (160–400 cm) and groundwater (910 cm). Diurnally, T. ramosissima SSF showed a hysteresis response to variations in PAR, Ta, and VPD, which suggests that transpiration suffers increasingly from water stress with increasing PAR, Ta, and VPD. Our results indicate that PAR, Ta, and VPD are the dominant factors that control T. ramosissima SSF, not precipitation and shallow soil moisture. Deep soil water and groundwater are the primary sources for T. ramosissima in this extremely water-limited environment. These results provide information that is essential for proper water resource management during vegetation restoration and ecological reafforestation in water-limited regions.

Different Arbuscular Mycorrhizal Fungi Established by Two Inoculation Methods Improve Growth and Drought Resistance of Cinnamomum Migao Seedlings Differently.

Simple SummaryDrought is a global climatic phenomenon and one of the main factors that negatively affect plant growth. Karst is a unique type of ecosystem where ecological degradation is becoming more and more serious due to the aggravation of global drought. Vegetation restoration is an effective method for preventing ecological degradation in Karst ecosystems. Cinnamomum migao is selected as the tree species for vegetation restoration, because it is a unique, fast-growing medicinal plant of Southwest China that only thrives in Karst regions. Arbuscular mycorrhizal fungi (AMF) are an important component of the soil biota in ecosystems and alleviate drought stress in plants by forming a mutualistic symbiosis. Most previous studies just considered the effects of AMF species on drought resistance but did not evaluate different inoculation methods. The aim of the present study was to compare the effects of different AMF resulting from the use of different inoculation methods on the growth and drought resistance of C. migao seedlings in Karst soil. The findings of this study will improve the success rate of reforestation programs in Karst ecosystems through the utilization of these important microorganisms.Drought stress is one of the greatest obstacles affecting field crop productivity in arid and semi-arid regions, and its severity and frequency are expected to increase due to human-induced changes to the environment and climate. Drought has led to rocky desertification in Karst regions. Cinnamomum migao is a unique, fast-growing medicinal plant of Southwest China that only thrives in Karst regions. Arbuscular mycorrhizal fungi (AMF) symbiosis alleviates drought stress in plants; however, establishment and function of the symbiotic interaction between AMF host plant in relation to the inoculation method remain unclear. Therefore, we conducted an experiment to investigate the effects of AMF species (Glomus etunicatum and Funneliformis mosseae) and two inoculation methods (seed vs. seedling inoculation) under drought stress on C. migao seedlings, and quantified mycorrhizal colonization, AMF spore density, root vigor, relative water content, C. migao growth, antioxidant enzyme activities, and osmotic adjustment. Inoculation with AMF (G. etunicatum and F. mosseae) positively affected the growth and root vigor of Cinnamomum migao under drought stress, regardless of the inoculation method. Additionally, both AMF species markedly upregulated antioxidant enzyme activities and osmotic adjustment substances, regardless of the inoculation method. Our results showed that the collective stimulatory effect of G. etunicatum is more efficient than that of F. mosseae. AMF application could promote afforestation with C. migao to prevent rocky desertification in Karst regions where water is the greatest limiting factor on plant growth and yield.

Caring of the Fringe? Mediterranean Desertification between Peri-Urban Ecology and Socioeconomics

This commentary debates on the role of multiple socioeconomic drivers of fringe land degradation (including, but not limited to, population and social dynamics, economic polarization, and developmental policies), as a novel contribution to the desertification assessment in Southern European metropolitan regions, a recognized hotspot of desertification at the global scale. Expanding rapidly all over the world, metropolitan regions are a geographical space where land degradation drivers and processes assume typical relationships that require further research supporting dedicated policy strategies. To assure a better comprehension of the environmental-economic nexus at the base of land degradation in peri-urban areas, we provided a classification of relevant socioeconomic and territorial dimensions in both macro-scale and micro-scale degradation processes. We also identified the related (contextual) factors that determine an increased risk of desertification in metropolitan regions. Micro-scale factors, such as agricultural prices and off-farm employment, reflect some potential causes of fringe land degradation, with a mostly local and on-site role. Technological change, agricultural prices, and household income influence land vulnerability, but their impact on fringe land degradation was less investigated and supposed to be quite moderate in most cases. Macro-scale factors such as population density, rural poverty, and environmental policies—being extensively studied on a qualitative base—were taken as important drivers of fringe land degradation, although their impact still remains undefined. Regional disparities in land resource distribution, rural poverty, and unsustainable management of environmental resources like soil and water were indirect consequences of land degradation in peri-urban districts. Based on a comparative review of theoretical and empirical findings, strategies mitigating degradation of fringe land and reducing desertification risk in potentially affected metropolitan regions were finally discussed for the Northern Mediterranean basin and generalized to other socioeconomic contexts.

Vegetation recovery and recent degradation in different karst landforms of southwest China over the past two decades using GEE satellite archives

Over the past two decades, eco-engineering has been recognized as an important restoration approach to promote vegetation regrowth and greenness in a widespread rocky desertification land of southwest China. However, it remains unclear of recovery patterns and dominating drivers in different types of karst landforms. Here we use multi-satellite archives based on Google Earth Engine (GEE) to reveal the rapid greening process although encountered severe drought, especially in Karst Peak-Cluster Depression (+0.0035y−1) and Karst Trough Valley (+0.0035y−1) influenced by subtropical monsoon climate and afforestation endeavor, while degradation happened recently at non-karst areas of west highland in Karst Fault Basin (−0.0043y−1 since 2006) and Karst Plateau (−0.0039y−1 since 2014) influenced by decreasing rainfall. Afforestation project and sloping land conversion program is found to play crucial part in explaining a large part of the greening trend in Peak-Cluster Depression and Trough Valley but not in other landforms, suggesting that geomorphic heterogeneity should be further considered in restoration implementation and vegetation assessment, in conjunction with climate change and anthropogenic factors. Our study provides a helpful perspective for karst conservation priorities of various rocky desertification region ecosystems.

湘西石漠化区3种造林模式土壤真菌群落结构差异

PDF HTML阅读 XML下载 导出引用 引用提醒 湘西石漠化区3种造林模式土壤真菌群落结构差异 DOI: 10.5846/stxb202008072061 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 中央级科研院所基本科研业务费重点项目（CAFYBB2019SZ003）；中南林业科技大学研究生科技创新基金（CX20192026） Differences of soil fungal community structure under three afforestation modes in rocky desertification region of Western Hunan Province Author: Affiliation: Fund Project: “Degradation mechanism and restoration technology of typical forests in South China 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:湘西石漠化地区是我国生态系统脆弱而又敏感的区域，土壤微生物在维持石漠化区森林生态系统结构和功能稳定中发挥重要作用。选取石漠化地区立地条件相同的32年生的马尾松纯林、光皮桦纯林及马尾松-光皮桦混交林为研究对象，以立地条件相似的未造林荒地演变成的灌草群落作为对照，比较分析石漠化地区不同造林模式对土壤真菌群落结构和多样性的影响及其主要驱动因素。采用Illumina HiSeq第二代高通量测序技术，分析了3种森林土壤真菌群落组成及多样性。结果表明，不同造林模式下土壤真菌优势类群不同，光皮桦、马尾松-光皮桦混交林以及石漠化灌草地土壤真菌优势门均为子囊菌门（Ascomycota），且在石漠化灌草地相对丰度最大，为64.0%；马尾松则以担子菌门（Basidiomycota）为优势类群，其相对丰度占57.9%。混交林土壤真菌物种总数和Shannon指数显著高于马尾松和光皮桦林地，整体上真菌群落多样性表现为：未造林灌草地 > 混交林 > 马尾松林 > 光皮桦林。与未造林灌草地相比，马尾松-光皮桦混交林和光皮桦纯林显著提升了土壤有机碳（SOC）和全氮（TN）含量。Mantel test检验结果显示，真菌群落结构与全磷（TP）、有机碳（SOC）、铵态氮（NH4+-N）、硝态氮（NO3--N）、全氮（TN）、pH和含水量（SWC）具有显著相关性（P<0.05），其中土壤SOC、TN、pH值对真菌群落结构影响最大。冗余分析（RDA）结果发现，子囊菌（Ascomycota）与pH、TP、SOC、TN、AP、NO3--N含量均呈正相关；担子菌门（Basidiomycota）和被孢霉门（Mortierellomycota）主要与NH4+-N成正相关，与pH、TP、SOC、TN、AP、NO3--N呈负相，而罗氏菌门（Rozellomycota）与SWC呈正相关（P<0.05）。综上，相比针叶纯林，石漠化地区针阔混交林能通过增加土壤SOC、TN而显著提高真菌群落多样性，促进土壤肥力状况的提升。此研究结果可以为石漠化区人工植被恢复以及土壤肥力管理提供依据。 Abstract:Rocky desertification area in Western Hunan province is a fragile and sensitive area of ecosystem in China. Soil microorganisms play an important role in maintaining the stability of forest ecosystem structure and function in rocky desertification area. Thirty two year-old pure Pinus massoniana forest, pure Betula luminifera forest and mixed Pinus massoniana and Betula luminifera forest in rocky desertification area with the same site conditions were selected as the research objects. The non-forested shrub grassland with the similar site conditions was taken as the control to compare and analyze the influence of different afforestation modes on soil fungal community structure and diversity and their main driving factors. The composition and diversity of soil fungal communities in three forests were analyzed by Illumina HiSeq second-generation high-throughput sequencing technology. The results showed that the dominant groups of soil fungi were different under different afforestation modes. The dominant phylum of soil fungi in Betula luminifera, mixed forest and non-forested shrub grassland were Ascomycota, and the relative abundance was the largest in non-forested shrub grassland, which was 64.0%. Basidiomycota was the dominant group in Pinus massoniana, its relative abundance accounted for 57.9%. The total number of soil fungal species and Shannon index of mixed forest were significantly higher than those of Pinus massoniana and Betula luminifera forest. On the whole, the diversity of fungal community was as follows:non-forested shrub grassland > mixed forest > Pinus massoniana forest > Betula luminifera forest. The contents of soil organic carbon (SOC) and total nitrogen (TN) in the mixed forest and Betula luminifera pure forest were significantly higher than those in non-forested shrub grassland. Mantel test showed that fungal community structure was significantly correlated with total phosphorus (TP), SOC, ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N), TN, pH and water content (SWC) (P<0.05). Soil SOC, TN and pH had the greatest impact on fungal community structure. Redundancy analysis (RDA) showed Ascomycetes were positively correlated with pH, TP, SOC, TN, AP and NO3--N content; Basidiomycetes and Mortierella were mainly positively correlated with NH4+-N, and negatively correlated with pH, TP, SOC, TN, AP and NO3--N. There was a positive correlation between Rozellomycota and SWC. In conclusion, compared with pure coniferous forest, coniferous and broad-leaved mixed forest in rocky desertification area can significantly improve the diversity of fungal community by increasing soil SOC and TN, and promote the improvement of soil fertility. The results can provide basis for artificial vegetation restoration and soil fertility management in rocky desertification area. 参考文献 相似文献 引证文献

Solar Energy Resources in Desertification Regions of China and Development Suggestions

To achieve the goal of carbon peaking and carbon neutralization, we need to accelerate the construction of a clean, low-carbon, safe and efficient energy system, implement renewable energy substitution actions, and constantly increase the proportion of non fossil energy consumption. China's deserts, Gobi and desert areas cover a vast area, and solar energy resources are abundant. The regions that can be developed by technology account for more than 60% of the whole country. Give full play to the characteristics of desert, Gobi and desert areas that are rich in wind and solar energy resources, have good construction conditions, and are less affected by land use. In combination with the power grid and consumption and utilization conditions, comprehensively promote large-scale development and high-quality development of solar energy, it is an important measure to promote the clean, low-carbon, safe and efficient transformation of the energy structure. To vigorously develop photovoltaic projects in desert, Gobi and desert areas, we need to adhere to large-scale and intensive development, to adhere to multi energy complementary ecological integration development, demonstration and guidance, which can help strengthen the comprehensive utilization of land, solar energy resources and other resources, and also obtain significant ecological, economic and carbon reduction benefits. At the same time, developing photovoltaic bases in desert regions can also improve the supply capacity of renewable energy and increase the supply level of clean low-carbon energy.

Fighting climate change: soil bacteria communities and topography play a role in plant colonization of desert areas.

Global warming has exacerbated desertification in arid regions. Exploring the environmental variables and microbial communities that drive the dynamics of geographic patterns of desert crops is important for large-scale standardization of crops that can control desertification. Here, predictions based on future climate data from CMIP6 show that a steady expand in the suitable production areas for three desert plants (Cistanche deserticola, Cynomorium songaricum and Cistanche salsa) under global warming, demonstrating their high adaptability to future climate change. We examined the biogeography of three desert plant soil bacteria communities and assessed the environmental factors affecting the community assembly process. The α-diversity significantly decreased along elevated latitudes, indicating that the soil bacterial communities of the three species have latitude diversity patterns. The neutral community model evaluated 66.6% of the explained variance of the bacterial community in the soil of desert plants and Modified Stochasticity Ratio <0.5, suggesting that deterministic processes dominate the assembly of bacterial communities in three desert plants. Moreover, topography (longitude, elevation) and precipitation as well as key OTUs (OTU4911: Streptomyces eurythermus and OTU4672: Streptomyces flaveus) drive the colonization of three desert plants. This research offers a promising solution for desert management in arid areas under global warming.

Analysis on the influence of rainfall characteristics on soil and water loss in rocky desertification region

Analysis on the influence of rainfall characteristics on soil and water loss in rocky desertification region