Desert Highway Research Articles

Bioprospecting of Soil-Derived Actinobacteria Along the Alar-Hotan Desert Highway in the Taklamakan Desert.

Taklamakan desert is known as the largest dunefield in China and as the second largest shifting sand desert in the world. Although with long history and glorious culture, the Taklamakan desert remains largely unexplored and numerous microorganisms have not been harvested in culture or taxonomically identified yet. The main objective of this study is to explore the diversity, novelty, and pharmacological potential of the cultivable actinomycetes from soil samples at various sites along the Alar-Hotan desert highway in the Taklamakan desert. A total of 590 actinobacterial strains were recovered by the culture-dependent approach. Phylogenetic analysis based on 16S ribosomal RNA (rRNA) gene sequences unveiled a significant level of actinobacterial diversity with 55 genera distributed in 27 families of 12 orders. Thirty-six strains showed relatively low 16S rRNA similarities (<98.65%) with validly described species, among which four strains had already been characterized as novel taxa by our previous research. One hundred and forty-six actinobacterial isolates were selected as representatives to evaluate the antibacterial activities and mechanism of action by the paper-disk diffusion method and a double fluorescent protein reporter “pDualrep2” system, respectively. A total of 61 isolates exhibited antagonistic activity against the tested “ESKAPE” pathogens, among which seven strains could produce bioactive metabolites either to be able to block translation machinery or to induce SOS-response in the pDualrep2 system. Notably, Saccharothrix sp. 16Sb2-4, harboring a promising antibacterial potential with the mechanism of interfering with protein translation, was analyzed in detail to gain deeper insights into its bioactive metabolites. Through ultra-performance liquid chromatography (UPLC)-quadrupole time-of-flight (QToF)-MS/MS based molecular networking analysis and databases identification, four families of compounds (1–16) were putatively identified. Subsequent bioassay-guided separation resulted in purification of four 16-membered macrolide antibiotics, aldgamycin H (8), aldgamycin K (9), aldgamycin G (10), and swalpamycin B (11), and their structures were elucidated by HR-electrospray ionization source (ESI)-MS and NMR spectroscopy. All compounds 8–11 displayed antibacterial activities by inhibiting protein synthesis in the pDualrep2 system. In conclusion, this work demonstrates that Taklamakan desert is a potentially unique reservoir of versatile actinobacteria, which can be a promising source for discovery of novel species and diverse bioactive compounds.

Hydrothermal Effects of Freeze-Thaw in the Taklimakan Desert

The Taklimakan Desert, also known as the “Sea of Death”, is the largest desert in China and also the world’s second largest remote desert. The road crossing the Taklimakan Desert is the longest desert road in the world and has been the center of the Silk Road since ancient times. Based on field observation data (November 2013 to May 2014) collected from the Tazhong and Xiaotang stations, we studied the interannual and diurnal variations of soil temperature, soil moisture content, and surface heat fluxes during different freezing and thawing periods. The annual and daily changes of soil temperature, soil moisture content, and surface energy fluxes at different freezing and thawing stages were analyzed. We illustrated the coupling relationship between water and heat in freezing-thawing soil in the Taklimakan Desert. We established a coupling model of soil water and heat during freezing and thawing. During the soil freezing period, the soil temperatures at different depths generally trended downward. The temperature difference between the Tazhong station and the Xiaotang station was 4~8.5 °C. The freezing time of soil at 20 cm depth occurred about 11 days after that at 10 cm depth. The effect of ambient temperature on soil temperature gradually weakened with the increase of soil depth. With the occurrence of the soil freezing process, the initial soil moisture contents at 5 cm, 10 cm, 20 cm, and 40 cm depths at the Xiaotang station were 6%, 10%, 29%, and 59%, respectively, and those at the Tazhong station were 5%, 3.6%, 4.4%, and 5.8%, respectively. As the ambient temperature decreased, the freezing front continued to move downward and the liquid soil water content at each depth decreased. The desert highway is closely related to the economic development and prosperity of southern Xinjiang. Therefore, it is important to maintain and inspect the safety and applicability of freeze-thaw zones and avoid casualties from vehicles and personnel.

Overview of the Measures and Techniques Used to Protect Traffic Lines against Shifting Sands in China

Shifting sands are one of the main contributors to desertification in China. This paper briefly reviews the measures and techniques which are used to protect traffic lines by stabilizing and fixing sands in the desert and desertification-affected arid and semi-arid areas in north China. We introduce the types and features of these measures and techniques, including mechanical, chemical, and biological measures, and outline how they have been applied in different areas and in different traffic lines over the past six decades, from 1950s to 2010s, taking the Baotou-Lanzhou railway, the Qinghai-Tibet railway, and the Tarim Desert highway as examples Mechanical measures such as erecting sand-retaining wind walls and placing straw checkerboards have proved to be very efficient for stabilizing shifting sands and protecting traffic lines that pass through the desert areas. Chemical measures are not widely used in the current sand fixing systems because of their high cost and potential pollution risks. Biological measures are preferred because they exhibit much better sand fixation performance and longer duration than the former two types of measures despite their relatively high cost. A combination of different measures is usually adopted in some areas to attain better sand-fixing effects. Stabilizing sand dune surfaces with mechanical measures or irrigation from underground water or river if available helps early recruitment of some drought-tolerant plants (xerophytes). We also point out the restrictions for existing sand-fixing measures and techniques and future research orientation. This review has implications for addressing eco-environmental issues associated with infrastructure construction that is part of the Belt and Road Initiative in desert and desertification-affected arid and semi-arid areas in the Mongolian Plateau.

Damage by wind-blown sand and its control measures along the Taklimakan Desert Highway in China

Desertification is one of the most serious environmental problems in the world, especially in the arid desert regions. Combating desertification, therefore, is an urgent task on a regional or even global scale. The Taklimakan Desert in China is the second largest mobile desert in the world and has been called the “Dead Sea” due to few organisms can exist in such a harsh environment. The Taklimakan Desert Highway, the longest desert highway (a total length of 446 km) across the mobile desert in the world, was built in the 1990s within the Taklimakan Desert. It has an important strategic significance regarding oil and gas resources exploration and plays a vital role in the socio-economic development of southern Xinjiang, China. However, wind-blow sand seriously damages the smoothness of the desert highway and, in this case, mechanical sand control system (including sand barrier fences and straw checkerboards) was used early in the life of the desert highway to protect the road. Unfortunately, more than 70% of the sand barrier fences and straw checkerboards have lost their functions, and the desert highway has often been buried and frequently blocked since 1999. To solve this problem, a long artificial shelterbelt with the length of 437 km was built along the desert highway since 2000. However, some potential problems still exist for the sustainable development of the desert highway, such as water shortage, strong sandstorms, extreme environmental characteristics and large maintenance costs. The study aims to provide an overview of the damages caused by wind-blown sand and the effects of sand control measures along the Taklimakan Desert Highway. Ultimately, we provide some suggestions for the biological sand control system to ensure the sustainable development of the Taklimakan Desert Highway, such as screening drought-resistant species to reduce the irrigation requirement and ensure the sound development of groundwater, screening halophytes to restore vegetation in the case of soil salinization, and planting cash crops, such as Cistanche, Wolfberry, Apocynum and other cash crops to decrease the high cost of maintenance on highways and shelterbelts.

Effects of windblown sand damage on desert highway guardrails

Barriers, which are normally used as highway safety instruments, cause adverse sand deposition damage to pavements along desert highways. To select a suitable barrier type for desert highways, this study conducted wind tunnel experiments and field test to measure the velocity field and sediment deposition morphology for different types of barriers. The results indicate that the velocity decreases in the foot of the subgrade, and the smooth air flow is maintained along the pavement. Wind velocity decreases slightly under the W-beam bottom, and the maximum velocity reduction is in the lee of the W-beam barrier. Wind velocity considerably decreases before and after the concrete barrier because of the dense structure of the barrier. Cable barriers slightly disturb the air flow and marginally decrease its velocity. Sediment deposition characteristic measurements demonstrate that for W-beam median barrier, sand is deposited on pavement in the lee of the barrier; further, for both W-beam roadside barrier and median barriers, sand is easy to be deposited in the front and back of the barrier, mainly on the windward pavement. For concrete barriers, considerable amount of sand is deposited in the front and back of the barriers, which induces the serious sand deposition damage on the pavement. The cable barrier causes minimal sand deposition, and it is a recommended structure for the barrier selection of desert highways. Further, small wind incidence angles are also favorable when designing desert highways.

Vertical Distribution of Soil Dissolved Carbon and Its Influencing Factors in the Artificial Shelterbelt Irrigated with Saline Water in an Extreme Drought Desert

Dissolved carbon (DC) is the most active carbon fraction in soils. Vegetation restoration and reconstruction accelerate the carbon cycle in arid desert regions. Studying the DC distribution in soil profiles of artificial shelterbelt under saline irrigation can provide theoretical support and decision-making basis for artificial shelterbelt management, development, and utilization in arid desert areas. In this study, we took the artificial shelterbelts drip-irrigated with five different mineralization and one shifting sandy land (CK) along the Taklimakan Desert Highway as sampling plots, analyzed and discussed the vertical distribution characteristics of soil dissolved organic carbon (SDOC) and dissolved inorganic carbon (SDIC) in the 0-1 m profiles, and further analyzed their relationships among different factors. The results showed that SDOC and SDIC of CK and shelterbelts under 2.82 g·L-1 irrigation showed an "I" type distribution with a linear function relationship. The SDOC and SDIC of four other treatments showed a "Γ" type distribution with power function relationships. The fluctuation ability and contribution degree of SDOC and SDIC of different treatments in the surface layer were higher than those in the lower layers, and the fluctuation and contribution intensity of SDOC were higher than those of SDIC. Except for 2.82 g·L-1 treatment, the average SDOC contents of other treatments were 2-4 times those of SDIC. The average SDOC content of 2.82 g·L-1 treatment was lower than CK; other treatments were 3-5 times that of CK; and the average SDIC content of all treatments increased 15.0%-57.9% than CK. For the 0-5 cm layer, SDOC content increased with the irrigation water mineralization except the 2.82 g·L-1 treatment, but SDIC content firstly increased and then decreased with increasing mineralization, and that for the 4.82 g·L-1 treatment was highest. The SDOC and SDIC were positively correlated with EC, SOC, irrigation water mineralization, SIC, and soil moisture, for which they both showed a weak positive correlation with soil moisture; they were negatively correlated with soil depth. The SDOC and SDIC showed a weak negative correlation and a weak positive correlation with pH, respectively. In summary, the mineralization of irrigation water has an important impact on the vertical distribution of SDOC and SDIC, and their distribution also has close relationships with EC, SOC, SIC, soil moisture, and soil depth, which is of great significance for plantations in extremely drought deserts.

Groundwater hydrology and characteristics of the tertiary aquifers, Northwest Cairo, Egypt

ABSTRACT The study area lies to the northwest of Cairo at Km.34 (Cairo – Alexandria Desert Highway) between latitudes 30° 00' 00" N & 30° 10' 00" N and longitudes 30° 50' 00" E & 31° 10' 35" E. It attains an area of about 590 Km2. The main objective of the present work is to focus on the configuration and assessment of groundwater potentials of the Tertiary aquifers including the Lower Miocene (Moghra Formation), Oligocene and Eocene limestone. These aquifers are considered as moderately productive where their transmissivity values are (197.5 &1352), 92.9 and 150 m2/day and their specific capacity are (5.9 & 12.7), 7.6 and 5.2 m3/h/m, for the Miocene, Oligocene and Eocene aquifers, respectively. The general flow direction of the groundwater is from east to west and from southeast to northwest with some local changes which may be attributed to the over-exploitation at these locations. The ranges of the water salinities of these aquifers are 288-3776, 2000-3100 and 2715-13120 mg/l for the Miocene, Oligocene and Eocene aquifers, respectively. The inferred faults play an important role in the direct hydraulic connection between the three aquifers.

The Desert Highway for Our God

Research Article| May 01 2019 The Desert Highway for Our God William Deverell William Deverell william deverell is a Professor of History at USC and Director of the Huntington-USC Institute on California and the West. Search for other works by this author on: This Site PubMed Google Scholar California History (2019) 96 (2): 3–5. https://doi.org/10.1525/ch.2019.96.2.3 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation William Deverell; The Desert Highway for Our God. California History 1 May 2019; 96 (2): 3–5. doi: https://doi.org/10.1525/ch.2019.96.2.3 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentCalifornia History Search This content is only available via PDF. © 2019 by the Regents of the University of California. All rights reserved. Please direct all requests for permission to photocopy or reproduce article content through the University of California Press's Reprints and Permissions web page, http://www.ucpress.edu/journals.php?p=reprints.2019 Article PDF first page preview Close Modal You do not currently have access to this content.

Inspection and Assessment of Highway Bridges in Jordan along the Desert Highway: A Case Study

Bridges, especially highway bridges, are a key factor in nations’ development and flourish. Thus, great care should be taken to maintain and inspect their safety and serviceability. An immediate repair will prevent the loss of life and vehicles damage while crossing underpass and overpassing the heavy deteriorated bridges. Reinforced or pre-stressed concrete bridge girders become structurally deficient because of severed reasons including, increasing in the load requirements, corrosion of pre-stressing strands or reinforcement bars and collision of over-height trucks with the bulb of the concrete girders. The purpose of this case study is to evaluate and assess the damages of the highway bridges in Jordan. Since there is no mandatory program in Jordan for inspection of bridges and evaluating their conditions, this paper presents an inspection and assessment of two highway bridges along the desert highway which is the essential nerve connecting Jordan cities, and it also serves as an international road between many middle east countries. These two Bridges have never been investigated or checked since their construction in the late 1980s. The study results showed that the main factor causing the deterioration of these bridges is the collision of the over-height trucks with their elements. Relying on the collected data, solutions and repair methods were introduced to rehabilitate these bridges and assure their structural safety.

Characteristics of Decomposition in the Soil Organic Carbon of the Tarim Desert Highway Shelter-belt

The Tarim Desert Highway Shelter-belt is in hinterland of the Taklimakan Desert, the decomposition of litter is an important source of the soil nutrients in the shelter-belt. To study the decomposition law of organic carbon after having input the litters into the soil, the decomposition mode of the litters was tested. The organic carbon contents at the soil surface and subsurface of the three kinds of shelter-belt plants were studied in terms of decomposition time, soil depth, and the change of water salinity. The results show that, with the increase of decomposition time and soil depth, the content of soil organic carbon increased; the content of soil organic carbon increased with the increase of salinity of the irrigation water. In terms of the effect of content of the soil organic carbon, Tamarix chinensis > Calligonum mongolicum > Haloxylon ammodendron. With the increase of decomposition time, the content of organic carbon at the soil surface increased, and the fastest increase appeared in the winter and the early spring, The content of organic carbon at the soil subsurface increased the most in the late spring and the summer; with the increase of decomposition time, the content of soil organic carbon was more obvious in different saline water, and the content of soil organic carbon increased with the decreasing salinity of the irrigation water. The results of this study can help to evaluate the potential of the carbon sequestration of the shelter-belt and provide scientific basis for the scientific management of the shelter-belt.

Influence of plantation of a shelter-belt on component of organic carbon in the Taklimakan desert over last decade

The soils were collected from the Taklimakan Desert Highway shelter-belt with different planting years in Xinjiang, northwest of China. The soil organic carbon stork (SOCstork) in each layers. By chemical and physical pretreatment, we measured four carbon passive organic carbons, i.e., microaggregates organic carbon(OCMIA), humus organic carbon (OCHS), carbon resistance to oxidation (OCNaClO) and acid hydrolysis (OCHCl). The results showed that the OC and SOCstorkwas decreased with soil depth mainly in 0-50 cm. The artificial vegetation have more influence on TOC, OCMIAand OCHSthan OCNaClOand OCHCl. The Tamarix chinensis shelter-belt is the most helpful for carbon sequestration in sandy soil and stabilization in surface layer than Calligonum mongolicunl and Haloxylon ammodendron.

MINAT BELI KONSUMEN TOKO SEPATU BATA DIPASAR RAYA PADANG DILIHAT DARI SIKAP DAN IKLAN

The company is engaged in the manufacture, import, export and distribution of leather shoes, built-up canvas, casual and sports shoes, injection slippers, and special shoes for industry. This study aimed to analyze the influence of each variable, the attitude (X1), advertising (X2) toward purchase intention. Data were collected through questionnaires. to 100 respondents Bata store consumer markets desert highway by using accidental sampling method to determine the respondents to each variable. By using the validity test, reliability test, descriptive analysis, multiple linear regression analysis, the coefficient of determination (R2), t-test, f. Data analysis technique used is multiple linear analysis. The result of this study shows that attitude and advertising have a significant effect on consumer buying interest in the purchase of shoes brick desert highway market.

Soil aggregation formation in relation to planting time, water salinity, and species in the Taklimakan Desert Highway shelterbelt

Purpose Soil formation and development can play an important role in the control of desertification in artificially forested desert areas. Here, we aimed to investigate soil aggregate formation in the Taklimakan Desert Highway shelterbelt (TDHS), China.

The Shammakh to Ayl Archaeological Survey, Southern Jordan (2010–2012)

The Shammakh to Ayl Archaeological Survey, Southern Jordan (2010–2012)

Moderate irrigation intervals facilitate establishment of two desert shrubs in the Taklimakan Desert Highway Shelterbelt in China.

BackgroundWater influences various physiological and ecological processes of plants in different ecosystems, especially in desert ecosystems. The purpose of this study is to investigate the response of physiological and morphological acclimation of two shrubs Haloxylon ammodendron and Calligonum mongolicunl to variations in irrigation intervals.Methodology/Principal findingsThe irrigation frequency was set as 1-, 2-, 4-, 8- and 12-week intervals respectively from March to October during 2012–2014 to investigate the response of physiological and morphological acclimation of two desert shrubs Haloxylon ammodendron and Calligonum mongolicunl to variations in the irrigation system. The irrigation interval significantly affected the individual-scale carbon acquisition and biomass allocation pattern of both species. Under good water conditions (1- and 2-week intervals), carbon assimilation was significantly higher than other treatments; while, under water shortage conditions (8- and 12-week intervals), there was much defoliation; and under moderate irrigation intervals (4 weeks), the assimilative organs grew gently with almost no defoliation occurring.Conclusion/SignificanceBoth studied species maintained similar ecophysiologically adaptive strategies, while C. mongolicunl was more sensitive to drought stress because of its shallow root system and preferential belowground allocation of resources. A moderate irrigation interval of 4 weeks was a suitable pattern for both plants since it not only saved water but also met the water demands of the plants.

Litter decomposition and nutrient dynamics of three woody halophytes in the Taklimakan Desert Highway Shelterbelt

ABSTRACTLitter decomposition is a crucial biogeochemical process for C and nutrient cycling in nutrient-constrained environments, but the controlling factors on litter decomposition in an extremely arid desert region such as the Taklimakan Desert are relatively unknown. To evaluate the litter decomposition and nutrient dynamic characteristics, five primary litter types of three woody halophytes (Haloxylon ammodendron, Calligonum arborescens, and Tamarix ramosissima) along the Taklimakan Desert Highway Shelterbelt were monitored in litterbags during 420 days, when placed on the soil surface and buried by sand, respectively. The results indicated that the decomposition rate decreased in the order of assimilative branches of H. ammodendron (HA, 0.94), branches of T. ramosissima (TB, 0.55), assimilative branches of C. arborescens (CA, 0.53), seeds of C. arborescens (CS, 0.41), and old branches of H. ammodendron (HB, 0.21) in the surface placement. In contrast, the litters buried by sand displayed a significantly accelerated decomposition rate (F = 12.28, P < 0.01), which were 1.3, 1.8, 1.3, 2.3, and 2.8 times of that at surface placement for HA, TB, CA, CS, and HB, respectively. Decomposition of the litters was primarily affected by initial content of C and K, lignin and cellulose in both placements, and varied among decomposition stages and conditions. The old branches of H. ammodendron and branches of T. ramosissima presented P accumulation in both placements, whereas nutrients (N, P, K) and C showed a release pattern during the litter decomposition process, which was influenced by initial litter contents and decomposition rate.

咸水滴灌下塔里木沙漠公路防护林土壤生化作用强度及微生物生态特征

PDF HTML阅读 XML下载 导出引用 引用提醒 咸水滴灌下塔里木沙漠公路防护林土壤生化作用强度及微生物生态特征 DOI: 10.5846/stxb201606131142 作者: 作者单位: 中国科学院新疆生态与地理研究所,中国科学院新疆生态与地理研究所,中国科学院新疆生态与地理研究所,中国科学院新疆生态与地理研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41571498） Biochemical intensity and microbial eco-characterization of soils irrigated with saline water from the Tarim Desert Highway shelter-belt Author: Affiliation: Xinjiang Institute of Ecology and Geography,CAS,Xinjiang Institute of Ecology and Geography,CAS,Xinjiang Institute of Ecology and Geography,CAS,Xinjiang Institute of Ecology and Geography,CAS 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:土壤生化作用强度是表征土壤生物学活性的重要指标。选择传统研究方法，从氨化作用、硝化作用、固氮作用、纤维素分解、呼吸作用以及酶活性6个方面，揭示了咸水滴灌下塔里木沙漠公路防护林地土壤生化作用强度的分异规律。结果表明，（1）随防护林定植年限的增大，土壤氨化作用、固氮作用、纤维素分解和呼吸作用的强度均明显增强，其中氨化作用和呼吸作用变化尤为明显；而硝化作用强度有所减弱。（2）0-50 cm土体内，随土壤深度增大，生化作用强度提高，氨化作用、硝化作用、固氮作用、纤维素分解和呼吸作用强度的垂直差异均达极显著水平（F > F0.01）。（3）随防护林定植年限的增大，不同土壤酶活性的变化各异，其中，过氧化氢酶活性显著增大（F > F0.01），纤维素酶和蔗糖酶的活性明显提高（F > F0.05），而蛋白酶、磷酸酶和脲酶的活性变化不大（F < F0.05）。（4）回归分析表明，不同生化强度因子与土壤环境因子的最优回归方程不同，但决定系数均大于0.95；全盐、全氮和速效氮进入了所有回归方程，是决定塔里木沙漠公路防护林地土壤生化强度的关键土壤环境因子。因此，咸水滴灌条件下，塔克拉玛干沙漠腹地防护林土壤生化作用强度不断提高的趋势，这对于防护林工程的科学管理有重要指示意义。 Abstract:Biochemical intensity of soil is an important index for characterizing biological activity. In this study, traditional research methods were employed to determine the soil biochemical characteristics of the Tarim Desert Highway shelter-belt from six aspects, including ammonification, nitrification, azotification, cellulose decomposition, respiration, and enzymatic activity. The main experimental results were as follows:(1) With increasing years since planting, ammonification and respiration showed the greatest improvements; azotification and cellulose decomposition also showed significant improvements, but nitrification was weakened. (2) Vertical differences in ammonification, nitrification, azotification, cellulose decomposition, and respiration in the 0-50 cm soil layer reached highly significant levels (F > F0.01), and biochemical activity of the soil increased with depth. (3) As years since planting increased, catalase activity showed the greatest increase (F > F0.01), cellulose and invertase activity also significantly increased (F > F0.05), and protease, phosphatase, and urease activity only minimally increased (F < F0.05). (4) The optimal regression equations between different biochemical intensity factors and soil environmental factors differed, but the regression determination coefficients were > 0.95. Total salt, total nitrogen, and available nitrogen were included in all of the regression equations and were key factors in the determination of biochemical intensity of the soil in the Tarim Desert Highway shelter-belt. Therefore, in the hinterland of the Taklamakan Desert, biochemical intensity of soils from the shelter-belt lands that were drip-irrigated with saline water exhibited an increasing trend. This knowledge will aid in the scientific management of the shelter-belt project. 参考文献 相似文献 引证文献

塔里木沙漠公路防护林地表凋落物分解对施肥的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 塔里木沙漠公路防护林地表凋落物分解对施肥的响应 DOI: 10.5846/stxb201509061830 作者: 作者单位: 中国科学院新疆生态与地理研究所,中国科学院新疆生态与地理研究所,中国科学院新疆生态与地理研究所,中国科学院新疆生态与地理研究所,中国科学院新疆生态与地理研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41271341，41030530，41301038）；塔里木油田公司项目（971012080007）；水利公益性行业科研专项（201401049） Effects of fertilizer addition on surface litter decomposition in the Tarim Desert Highway shelterbelt Author: Affiliation: Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences,Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences,Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences,Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences,Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences 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:为探讨沙漠公路防护林地表凋落物的分解速率和养分释放动态对施肥的响应，采用凋落物分解袋法，对塔里木沙漠公路防护林地乔木状沙拐枣（Calligonum arborescens）同化枝、梭梭（Haloxylon ammodendron）同化枝和多枝柽柳（Tamarix ramosissima）枝凋落物在施肥处理下的分解及养分释放特征进行研究。结果表明：经过420d的分解，3种凋落物质量残留率在对照（不施肥）、施用氮肥、施用磷钾复合肥处理间存在显著性差异（P < 0.05）。乔木状沙拐枣同化枝、梭梭同化枝和多枝柽柳枝在对照处理下的质量残留率分别为56.95%、31.32%和50.24%。施肥处理下3种凋落物均呈现出梭梭同化枝分解速率最快，多枝柽柳枝次之，乔木状沙拐枣同化枝分解最慢。施用磷钾复合肥极显著提高了3种凋落物的分解速率（P < 0.01）；施用氮肥则促进多枝柽柳枝的分解，抑制乔木状沙拐枣和梭梭同化枝的分解。凋落物分解过程中，对照组3种植物凋落物的C、N、P和K元素均呈现净释放状态；施肥后凋落物的N、P和K元素呈现出富集-释放的模式。凋落物初始P含量和C/N、C/P比值是分解初期的主导因素，初始K、木质素、纤维素含量和C/N、木质素/N比值是分解后期的主要控制因素。研究表明，施肥显著影响沙漠公路防护林地表凋落物的分解，增加防护林地表凋落物的养分归还量，延后养分释放的时间，改善塔里木沙漠公路防护林地的土壤肥力。凋落物初始C/N比值是预测塔里木沙漠凋落物分解的重要因素，且不同分解时期影响凋落物分解的初始化学组成有所差异。 Abstract:Litter decomposition determines the nutrient and carbon cycling processes and regulates nutrient return to the soil in many terrestrial ecosystems. Wood plant litter decomposition is a crucial biogeochemical process for carbon and nutrient cycling, especially in arid and nutrient-constrained ecosystems. However, the role of litter decomposition in extreme drought deserts and the determining factors remain debatable and poorly understood. The Tarim Desert Highway Shelterbelt consists of three artificial plant species that account for the majority of net primary productivity, and their litters are the major contributors to carbon and nutrient recycling. In such artificial desert shelter forests, the addition of fertilizer causes contradictory effects on litter decomposition and nutrient dynamics. This study aims to (1) examine how the addition of fertilizer affects surface litter decomposition and nutrient dynamics, and (2) determine the major factors influencing litter decomposition in arid deserts. The litterbag method was used to investigate the assimilative branches decomposition of Calligonum arborescens and Haloxylon ammodendron, and the branches decomposition of Tamarix ramosissima in the Taklimakan Desert Research Station. Filled litterbags were placed on soil surfaces at different plots in March 2013. Fertilizer addition and irrigation were implemented from March to November during the experiment. Litterbags were collected in May, July, September, and November of 2013, and in March and May of 2014. The mass remaining, elemental content (carbon, nitrogen, phosphorus, and potassium), and decomposition rates of litter were analyzed at each decomposition stage. Results showed that after 420 days of decomposition, significant differences were found among control (without fertilizer), addition of nitrogen fertilizer, and phosphorus and potassium compound fertilizer treatments. The mass remaining for the assimilative branches of C. arborescens, assimilative branches of H. ammodendron, and branches of T. ramosissima without fertilizer addition were 56.95%, 31.32%, and 50.24%, respectively. The decomposition rate of fertilizer treatments among different litters was the highest for the assimilative branches of H. ammodendron, followed by the branches of T. ramosissima, and then the assimilative branches of C. arborescens. The addition of phosphorus and potassium compound fertilizer significantly accelerated the litter decomposition rate of the three plant species, whereas nitrogen fertilizer increased the decomposition rate of the branches of T. ramosissima and restrained the decomposition rate of the assimilative branches of C. arborescens and H. ammodendron. During the decomposition process, litter nutrients presented net release patterns in the treatments without fertilizer. In contrast, the nitrogen, phosphorus, and potassium contents of the fertilizer treatments showed an accumulation-release pattern. The litter decomposition rate was determined by the initial phosphorus content and C/N and C/P ratios at the initial decomposition stage. However, the decomposition rate was controlled by the initial potassium, lignin, and cellulose contents and C/N, and lignin/N ratios at the final stage. Overall, the results suggest that the addition of fertilizer significantly changed the decomposition rate of surface litters, increased the amount of returned nutrients, and postponed the time of nutrient release. Improving soil fertility in the Tarim Desert Highway shelterbelt is essential in enhancing the quality of this valuable ecosystem. The initial litter C/N ratio is critical to surface litter decomposition in the Tarim Desert, and the initial chemical composition to surface litter decomposition rate varies at different decomposition stages. 参考文献 相似文献 引证文献

Population Redistribution to Achieve Balanced Regional Sustainable Development in Upper Egypt (2006-2027)

The main objective of the study is to present practical solutions for the problem of building (and demolition) on agricultural lands in Upper Egypt; shortage of available lands for urban expansion; limiting slum areas at cities margins and random building in rural areas; creating new communities that achieve sustainable regional development; and redistribution of population and labor force in Upper Egypt. The study depends on population census data of 2006 for future estimates. The study adopts the descriptive analytical approach. The main results were as follows: - The problem of building (and demolition) on agricultural lands in Egypt represents a matter of life or death for the Egyptians. - The present pattern of random housing in cities and villages is neither sustainable nor balanced. - The traditional Egyptian villages must be re-planned without allowing for rebuilding old houses. - It is imperative to look for new locations to establish new communities to absorb the population increase and satisfy housing needs. The most important recommendations were as follows: - Preventing building in old cities, especially at the margins close to agricultural lands. - Preventing building on agricultural lands for any reason. - Establishing new twin cities (and villages) at the western desert highway, from Giza to Aswan. - Adopting the desert housing pattern (Hassan Fatehy engineering) to reduce costs and materials consumption. - Relocating specific governmental agencies from old to new communities. - Relocating boys secondary schools from old to new communities. - Utilizing the evacuated buildings of secondary schools to decrease densities of primary and preparatory schools in old communities. - Adoption of new and renewable energy sources, such as solar energy and biogas. - Establishing factories for wastes re-cycling at suitable sites in new communities. - Declaring a clear-cut stand as for no conciliation with building on agricultural lands, and imposing severe penalties up to land confiscation.

Effect of shifting sand burial on soil evaporation and moisture–salt distribution in a hyper-arid desert

It is a serious threat for the sustainable protection of the Taklimakan Desert Highway Shelterbelt (TDHS) from shifting sand burial. To explore the effects of shifting sand burial on soil evaporation, salt accumulation and their distribution, Micro-lysimeters were used under sand burial of different thickness (1, 3 and 5 cm) and particle size (<0.063, 0.063–0.20 and 0.20–2.00 mm). The results demonstrated that: (1) soil daily evaporation and accumulative evaporation decreased with the sand burial thickness, and thus evaporative inhibiting efficiency increased. Consequently, the soil water content increased with sand burial thickness (1.48–12.70%) than the control; (2) finer-textured (<0.063 mm) sand burial (0–2 cm depth) promoted soil evaporation and salt accumulation at topsoil, accumulative evaporation increased 5.1 mm and electrical conductivity (EC) of topsoil increased 13.30 dS m−1 compared with the control; and (3) while topsoil EC decreased 1.65–6.46 dS m−1 with the increase in sand burial thickness, soil EC beneath the sand burial interface showed a reverse trend. We concluded that shifting sand burial has obvious effects on soil water evaporation, salt accumulation and water-salt redistribution, and it could be considered to save water and reduce salt accumulation in arid desert areas like the TDHS with saline irrigation.