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Reasonable grazing may balance the conflict between grassland utilization and soil conservation in the semi-arid hilly areas, China

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Journal of Arid Land 2024年第8期16卷 1130-1146页

作者： SUN Hui zhao yunge GAO Liqian XU Mingxiang College of Forestry Northwest A&F UniversityYangling 712100China College of Soil and Water Conservation Science and Engineering Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100China

Soil erosion caused by unsustainable grazing is a major driver of grassland ecosystem degradation in many semi-arid hilly areas in ***,grazing exclusion is considered as an effective method for solving this issue in such ***,some ecological and economic problems,such as slow grassland rejuvenation and limited economic conditions,have become obstacles for the sustainable utilization of grassland ***,we hypothesized that the conflict between grassland use and soil conservation may be balanced by a reasonable grazing *** this study,a two-year grazing fence experiment with five grazing intensity gradients was conducted in a typical grassland of the Loess Plateau in China to evaluate the responses of vegetation characteristics and soil and water losses to grazing *** five grazing intensity gradients were 2.2,3.0,4.2,6.7,and 16.7 goats/hm2,which were represented by G1-G5,respectively,and no grazing was used as *** results showed that a reasonable grazing intensity was conducive to the sustainable utilization of grassland *** biomass under G1-G4 grazing intensity significantly increased by 51.9%,42.1%,36.9%,and 36.7%,respectively,compared with *** addition,vegetation coverage increased by 19.6%under G1 grazing *** diversity showed a single peak trend with increasing grazing *** Shannon-Wiener diversity index under G1-G4 grazing intensities significantly increased by 22.8%,22.5%,13.3%,and 8.3%,respectively,compared with ***,grazing increased the risk of soil *** with control,runoff yields under G1-G5 grazing intensities increased by 1.4,2.6,2.8,4.3,and 3.9 times,respectively,and sediment yields under G1-G5 grazing intensities were 3.0,13.0,20.8,34.3,and 37.7 times greater,respectively,than those under *** result was mainly attributed to a visible decrease in litter biomass after grazing,which decreased by 50.5%,72.6%,79.0%,80.0%

关键词： fence-controlled grazing rehabilitated grassland vegetation community characteristics soil erosion sediment biocrusts Loess Plateau

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Characteristic stress variation and microcrack evolution of granite subjected to uniaxial compression using acoustic emission methods

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3511-3523页

作者： yunge zhao Xibing Li Linqi Huang Zhichao Zhang Zihou Xu School of Resources and Safety Engineering Central South UniversityChangsha410083China

The size of mineral grain has a significant impact on the initiation and propagation of microcracks within *** this study,fine-,medium-,and coarse-grained granites were used to investigate microcrack evolution and characteristic stress under uniaxial compression using the acoustic emission(AE),digital image correlation(DIC),and nuclear magnetic resonance(NMR)*** experimental results show that the characteristic stress of each granite decreased considerably with increasing grain *** inflection points of the b-value occurred earlier with an increase in grain sizes,indicating that the larger grains promote the generation and propagation of *** distribution characteristics of the average frequency(AF)and the ratio of rise time to amplitude(RA)indicate that the proportion of shear microcracks increases with increasing grain *** NMR results indicate that the porosity and the proportion of large pores increased with increasing grain size,which may intensify the microcrack ***,analysis of the DIC and AE event rates suggests that the high-displacement regions could serve as a criterion for the degree of microcrack *** study found that granites with larger grains had a higher proportion of high-displacement regions,which can lead to larger-scale cracking or even *** findings are not only beneficial to understand the pattern of microcrack evolution with different grain sizes,but also provide guidance for rock monitoring and instability assessment.

关键词： Grain size Acoustic emission(AE) Characteristic stress Microcrack evolution Fracture mode

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Biocrusts impact soil properties and ecological stoichiometry characteristics in frozen ground regions on the Qinghai-Tibet Plateau

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Soil Ecology Letters 2024年第3期6卷 151-162页

作者： Jiao Ming yunge zhao Yingying Sun Zhe Liu The Research Center of Soil and Water Conservation and Ecological Environment Chinese Academy of Sciences and Ministry of EducationYangling 712100China College of Soil&Water Conservation Science and Engineering(Institute of Soil and Water Conservation) Northwest A&F UniversityYangling 712100China Institute of Soil and Water Conservation Chinese Academy of Sciences&Ministry of Water ResourcesYangling 712100China Shaanxi Provincial Land Engineering Construction Group Co. Ltd.Xi'an 710075China

Biocrusts(BSCs)are widely distributed in frozen ground regions on the Qinghai-Tibet Plateau,and they are considered an important component of cold ***,the specific impacts of BSCs on frozen soil remains relatively *** aim of our study was to clarify the influence of BSCs(light BSCs and dark BSCs in two different succession stages)on the physical properties and ecological stoichiometry characteristics of frozen *** results showed that BSCs increased the silt particle content in 20–40 cm soil layer,leading to a decrease in soil bulk *** the field water capacity increased about 10%–40%compared to bare ***,BSCs significantly increased the contents of soil organic carbon(SOC,22.6–30.8 g kg^(-1))and total nitrogen(TN,2.1–2.8 g kg^(-1))in the upper 40 cm soil layer,both of them were approximately 1.3–2.0 and 1.3–4.0 times higher than those observed in bare ***,BSCs did not have significant influence on soil total phosphorus(TP).BSCs had a significant impact on the stoichiometric ratios within 40 *** C/N ratios of the two types of BSCs ranged from 8.8 to 13.5,the C/P ratios ranged from 6.6 to 13.8,and the N/P ratios ranged from 0.6 to 1.2,which were all higher than those of the bare *** were no significant differences among the C/N,C/P,and N/P ratios between two types of ***,the increment of C/P and N/P ratios of dark BSCs were significantly higher than those of light BSCs within 0–30 cm,which indicated that a reduction in the availability of phosphorus during the later stages of BSCs *** findings provided a theoretical basis for further research on the ecological functions of BSCs in frozen ground regions.

关键词： biocrusts frozen soil soil properties stoichiometry characteristics Qinghai-Tibet Plateau

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故宫藏曲阳白石造像中龙的类型与来源

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紫禁城 2024年第2期 88-99页

作者：赵芸格故宫博物院器物部

龙作为佛教重要护法之一,常在佛教造像中出现。在故宫博物院保存的曲阳佛造像中就可见龙的身影。曲阳出土的佛造像上可见双树背屏上的盘龙、背屏上端的腾龙以及盘龙腾龙的组合形式。与邺城北吴庄和青州龙兴寺造像中的龙形象进行对比.

关键词：佛造像青州龙兴寺背屏曲阳佛教造像腾龙故宫博物院

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故宫博物院藏南华寺罗汉像考

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紫禁城 2024年第6期 80-91页

作者：赵芸格故宫博物院器物部

南华寺是中国佛教禅宗的主要道场,被誉为“岭南禅林之冠”“粤区西天宝林”。南华寺中数量最多、艺术价值最高的当属北宋木雕五百罗汉像。南华寺罗汉像现存三百六十尊,故宫博物院保存有五十尊,其中部分罗汉像底座前刻有发愿文。

关键词：发愿文南华寺佛教禅宗罗汉像故宫博物院道场

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黄土高原典型维管植物冠层下生物结皮的分布与预测

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应用生态学报 2024年第9期35卷 2571-2580页

作者：刘宁鱼舜尧张采月赵允格中国科学院教育部水土保持与生态环境研究中心陕西杨凌712100 西北农林科技大学水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室陕西杨凌712100 中国科学院水利部水土保持研究所陕西杨凌712100 中国科学院大学北京100049

维管植物可影响生物结皮的生存环境,进而影响其分布,目前鲜有研究关注维管植物的冠层特征与生物结皮空间分布特征的关系。本研究以黄土高原水蚀风蚀交错区为研究区,调查了维管植物冠层下方生物结皮的分布特征,采用相关性分析和随机森林... 详细信息

维管植物可影响生物结皮的生存环境,进而影响其分布,目前鲜有研究关注维管植物的冠层特征与生物结皮空间分布特征的关系。本研究以黄土高原水蚀风蚀交错区为研究区,调查了维管植物冠层下方生物结皮的分布特征,采用相关性分析和随机森林重要性排序的方法,分析了维管植物冠层特征与生物结皮空间分布的关系,基于随机森林模型构建了维管植物冠层下生物结皮面积的预测模型。结果表明:1)研究区生物结皮类型以藻结皮为主,藓结皮次之。2)维管植物冠层影响生物结皮空间分布,生物结皮主要分布在270°~315°和315°~360°两个方位,在90°~135°和135°~180°两个方位分布较少。3)径向上,生物结皮盖度由维管植物根部向冠层边缘表现出逐渐升高的趋势。4)冠层下生物结皮面积与维管植物冠层面积、长冠幅、短冠幅呈极显著正相关。5)冠层面积、长冠幅、短冠幅对冠层下生物结皮的重要性分别为13.7%、12.1%和11.9%,株高和物种类型的重要性较低,分别为6.7%和4.4%。6)随机森林模型在基于维管植物特征对生物结皮的预测中表现良好,预测精度为0.59(R^(2)),均方根差为1.2 m^(2),能够应用于维管植物冠层下生物结皮面积的预测和估算。本研究为进一步理解半干旱气候区维管植物与生物结皮之间的关系及生物结皮空间分布预测提供了理论依据。

关键词：维管植物生物结皮冠层特征空间分布随机森林

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斑块面积对干燥-复水条件下藓类植物生理活性的影响

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生态学报 2024年第5期44卷 2081-2088页

作者：乔羽赵允格高丽倩井海梦张珺雨西北农林科技大学资源环境学院杨凌712100 中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室杨凌712100

干扰会导致生物结皮斑块破碎并退化。为明确生物结皮斑块破碎诱发生物结皮退化机理,以黄土丘陵区土生对齿藓(Didymodon vinealis)结皮为研究对象,研究了干燥-复水条件下,单株和直径1 cm、2 cm、3 cm、4 cm、5 cm的藓结皮斑块内土生对齿... 详细信息

干扰会导致生物结皮斑块破碎并退化。为明确生物结皮斑块破碎诱发生物结皮退化机理,以黄土丘陵区土生对齿藓(Didymodon vinealis)结皮为研究对象,研究了干燥-复水条件下,单株和直径1 cm、2 cm、3 cm、4 cm、5 cm的藓结皮斑块内土生对齿藓的干燥速率、渗透调节物质、丙二醛和光合色素含量等的变化,以期揭示干扰后生物结皮退化的生物学机理。结果表明(1)除单株外,干燥速率随斑块面积减小而增加,直径1 cm斑块内藓的干燥速率是直径5 cm的2倍。(2)反复干燥-复水25天后,直径小于5 cm的斑块内藓的可溶性糖、可溶性蛋白和叶绿素含量低于直径5 cm斑块内藓的含量,丙二醛含量随斑块面积变化无明显规律。(3)干燥速率与斑块面积、可溶性糖、可溶性蛋白及叶绿素含量均呈极显著负相关。以上结果表明,藓结皮斑块面积通过影响斑块内藓类植物干燥速率进而影响其渗透调节和光合作用能力。藓结皮斑块面积减小,藓类植物干燥速率增大,生理活性降低,是藓结皮斑块破碎诱发其退化的原因。研究从藓类植物生理的角度,阐明了干扰后藓类植物衰亡的生理学原因,为生物结皮的保护和管理提供了科学依据。

关键词：藓结皮斑块面积干燥速率光合色素渗透调节

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干燥速率对黄土丘陵区林下藓类植物生理特征的影响

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生态学杂志 2024年第2期43卷 445-454页

作者：孙会高丽倩许明祥郭玥微赵允格西北农林科技大学林学院陕西杨凌712100 西北农林科技大学水土保持研究所陕西杨凌712100 中国科学院教育部水土保持与生态环境研究中心黄土高原土壤侵蚀与旱地农业国家重点实验室陕西杨凌712100

藓类植物是林地常见地被物,具有重要生态功能。水分是影响藓类植物生长发育最重要的因素,水分变化会引起藓类植物的生理响应。以黄土丘陵区林下厚角绢藓(Entodon concinnus)、荫地绢藓(Entodon caliginosus)、青藓(Barchythecium albica... 详细信息

藓类植物是林地常见地被物,具有重要生态功能。水分是影响藓类植物生长发育最重要的因素,水分变化会引起藓类植物的生理响应。以黄土丘陵区林下厚角绢藓(Entodon concinnus)、荫地绢藓(Entodon caliginosus)、青藓(Barchythecium albicans)为对象,研究了干燥速率对其生理特征的影响,以期明确其生理耐干性。结果表明:(1)3种藓在干燥后均受到了水分胁迫,3种藓干燥后的丙二醛(MDA)、可溶性蛋白、可溶性糖含量、过氧化物酶(POD)和超氧化物歧化酶(SOD)活性增加。(2)干燥速率对3种藓水分的胁迫程度不同,快干加剧了藓类植物的水分胁迫,快干后3种藓MDA、可溶性蛋白、可溶性糖含量,POD、SOD活性大于慢干。(3)干燥过程对藓类植物造成的水分胁迫有种间差异,3种藓干燥后MDA、可溶性蛋白、可溶性糖含量、POD、SOD活性增幅不同。(4)青藓有较高的耐干性,干燥后其氧化损伤较低,MDA含量在快干后显著低于荫地绢藓37.7%,慢干后显著低于厚角绢藓39.3%。青藓细胞调节能力较高,可溶性糖含量在快干后分别高出厚角绢藓和荫地绢藓57.3%和50.9%,慢干后分别高13.6%和99.8%。青藓抗氧化能力较强,快干后其POD活性较厚角绢藓和荫地绢藓分别增加120%和260%,慢干后分别增加19.4%和240.0%。同时,青藓具有较强的光合恢复能力,快干-复水后青藓叶绿素含量恢复率64.4%,显著高出厚角绢藓和荫地绢藓的55.7%和13.1%。以上结果表明,干燥增加了林下藓类植物的水分胁迫,干燥速率的增加可加剧藓类水分胁迫程度。不同藓种耐干性有差异,耐干性较强的藓种在干燥过程中有较强抵抗水分胁迫能力。研究结果可为藓类植物的生态功能研究及多样性保护提供科学依据。

关键词：林下藓类干燥速率干燥-复水抗氧化能力渗透调节能力

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Interactions between wind and water erosion change sediment yield and particle distribution under simulated conditions

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Journal of Arid Land 2015年第5期7卷 590-598页

作者： TUO Dengfeng XU Mingxiang zhao yunge GAO Liqian State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F University Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources

Wind and water erosion are among the most important causes of soil loss, and understanding their interactions is important for estimating soil quality and environmental impacts in regions where both types of erosion occur. We used a wind tunnel and simulated rainfall to study sediment yield, particle-size distribution and the fractal dimension of the sediment particles under wind and water erosion. The experiment was conducted with wind ero- sion firstly and water erosion thereafter, under three wind speeds （0, 11 and 14 m/s） and three rainfall intensities （60, 80 and 100 ram/h）. The results showed that the sediment yield was positively correlated with wind speed and rain- fall intensity （P〈0.01）. Wind erosion exacerbated water erosion and increased sediment yield by 7.25%-38.97% relative to the absence of wind erosion. Wind erosion changed the sediment particle distribution by influencing the micro-topography of the sloping land surface. The clay, silt and sand contents of eroded sediment were also posi- tively correlated with wind speed and rainfall intensity （P〈0.01）. Wind erosion increased clay and silt contents by 0.35%-19.60% and 5.80%-21.10%, respectively, and decreased sand content by 2.40%-8.33%, relative to the absence of wind erosion. The effect of wind erosion on sediment particles became weaker with increasing rainfall intensities, which was consistent with the variation in sediment yield. However, particle-size distribution was not closely correlated with sediment yield （P〉0.05）. The fractal dimension of the sediment particles was significantly different under different intensities of water erosion （P〈0.05）, but no significant difference was found under wind and water erosion. The findings reported in this study implicated that both water and wind erosion should be controlled to reduce their intensifying effects, and the controlling of wind erosion could significantly reduce water erosion in this wind-water erosion crisscross region.

关键词： sediment yield particle-size distribution fractal dimension wind and water erosion

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温度和初始pH对生物结皮中4种优势蓝藻生长的影响

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应用生态学报 2024年第2期35卷 516-522页

作者：王一帆李璇罗珊珊黄卓超丁真玉珍周楠赵允格西北农林科技大学资源环境学院陕西杨凌712100 西北农林科技大学生命科学学院陕西杨凌712100 西北农林科技大学水土保持科学与工程学院陕西杨凌712100 西北农林科技大学水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室陕西杨凌712100

生物土壤结皮对干旱半干旱地区生态环境健康及可持续发展有重要意义。具鞘微鞘藻、伪枝藻、念珠藻和鱼腥藻是生物结皮中蓝藻的优势种,对其大规模培养有着广阔的应用前景。以4种蓝藻为材料,采用室内液体培养方法,研究了5个温度(10、20、2... 详细信息

生物土壤结皮对干旱半干旱地区生态环境健康及可持续发展有重要意义。具鞘微鞘藻、伪枝藻、念珠藻和鱼腥藻是生物结皮中蓝藻的优势种,对其大规模培养有着广阔的应用前景。以4种蓝藻为材料,采用室内液体培养方法,研究了5个温度(10、20、25、30、35℃)和5个溶液初始pH(4、6、8、10、12)对4种藻生物量和溶液pH的影响。结果表明:在20℃以下温度培养,供试4种藻生物量增长缓慢,在25~35℃下4种藻均能正常生长,其中25和30℃下藻类生物量增长最快。不同藻种的最适培养温度略有区别,伪枝藻和念珠藻最适培养温度为25~30℃,具鞘微鞘藻和鱼腥藻为30℃。供试4种藻对溶液pH有极强的调节能力,均能够在5个初始pH环境中进行增殖,在初始pH为4的培养环境下能达到最大生物量和比生长速率,在初始pH为12下生物量和比生长速率最低。研究为生物结皮中优势藻的扩繁提供了科学依据。

关键词：具鞘微鞘藻伪枝藻念珠藻鱼腥藻生物量 pH

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