当代中国民粹主义的生发土壤及其生成背景

作为现代化进程的产物、一种具有周期复发性的社会政治现象,民粹主义在历史发展进程中不断徘徊于全球各地,给国家治理带来巨大纷扰。然而,民粹主义并非是从天上掉下来的或者是某些人心血来潮发明出来的,而是在特定社会历史环境下、受多重因素影响而衍生出来的,其有着自身独特的生发机制——"民"、"粹"、"民粹关系"以及"网络"基本上构成了当代中国网络时代民粹主义的生发土壤与生成背景。

Seed germination and seedling development of Prunus armeniaca under different burial depths in soil

A semi-greenhouse study was conducted to understand the effects of soil burial depth on seed germination and seedling development. The seeds of wild apricot （Prunus armeniaca） were buried at the soil depths of 0-cm, 4-cm, 8-cm, and 12-cm, respectively, to simulate the seed hoarding behavior of rodents in the field. The results revealed that the rates of seed germination and established seedlings from buried seeds were both the highest in 4-cm burial depth group, and then decreased with increasing soil depth. The number of rotten seeds increased in deeper burial depth. It is unfavourable for seed germination at 0-cm burial depth （i.e., seeds were laid on soil surface）. There was insignificant effect of burial depth on growth of established seedlings. The results from this study indicated that proper burial depth in soil would be helpful for the seed germination and seedling growth. The seedlings derived from buried seeds at shallower depth （4 cm） in this research have advantage in their early development.

Research Advance on Sod Culture in Peach Orchard

Sod culture in peach orchards is an advanced soil management. The significances of sod culture in peach orchard are introduced, as well as the sod ways. The effects of sod culture in a peach orchard on soil, microclimate and growth and development of peach tree, and disease, pest and weed are reviewed. The problems in sod culture in peach orchard in China are summarized. Sod culture could increase soil fertility, improve soil physical properties, relieve soil temperature change, increase soil microbial growth and soil enzyme activity, improve microclimate and fruit quality, reduce physiological disease, insect pests and weeds.

Age and Some Genetic Characteristics of Vertisols in China

The ages of organic matter of some dark-colored horizons and calcareous concretions in some Vertisols from tropical, subtropical and warm-temperate zones of China were studied using radiocarb on dating method. The relationship between soil age and genesis of Vertisols was also expounded based on the study of their genetic charactens-tics and micromorphological features. The results show that although Vertisols have developed for a relatively long time, their weathering and soil forming process are weak and young with little horizonation. This is closely related to their special geochemical soil forming environment. Low-lying terrain, heavy texture, clay minerals dominated by montmorillonites and alternative drying- wetting climate give rise to the vertic features expressed in intense swelling-shrinking and cracking-closing in soils. As a result, the soil development and soil leaching process are resisted, and the climatic effect on the horizonation is impeded. Moreover, pedoturbation eliminates the horizonation in the upper part of soil profile, and postpones their evolution into zonal soils. So Vertisols show certain pedogenic inertia and stay at relatively young developmental stage. Therefore, Vertisols are intrazonal soils dominated by local soil forming factors such as the relief and parent materials.

Soil Development and Fertility Characteristics of Inland Valleys in the Rain Forest Zone of Nigeria: Mineralogical Composition and Particle-Size Distribution

The particle-size distribution and mineralogical composition of the clay （〈 2 μm） and fine-sand （0.25-0.10 mm） fractions in soils of two inland valleys in Abakaliki and Bende, Southeast Nigeria, were investigated to provide basic information on soil-forming processes and agricultural potentials. These soils were silty or clayey, deriving from Cretaceous or Tertiary shale materials. The particle-size distribution and its computation on a clay-free basis revealed relatively remarkable lithologic breaks in a couple of pedons. The effect of lithologic discontinuities on soil mineralogical composition was not, however, conspicuous. Petrographic investigation revealed that quartz predominantly comprised the fine-sand fraction in the soils at both study sites. Nevertheless, the clay mineralogical composition of the soils was a mixture of kaolinite, irregularly interstratified smectite-illite intergrades （S/I）, hydroxyl-A1 interlayered 2：1 type clays （HICs）, vermiculite, smectite, halloysite and illite along with fine-sized quartz in Abakaliki. The soils of Bende predominantly contained smectite, which was partially interlayered with hydroxyl-A1 and kaolinite. It is suggested that seasonal floodwater has slowed the disintegration of weatherable clay minerals inherited from the shale, while quartz originating from the sandstone is predominant in the fine-sand fraction. Additionally, a possible soil-forming process observed at the both study sites was ferrolysis, which was indicated by a clear decreasing pattern of HICs downward in the soil profiles, The entry of S/I and vertical distribution patterns for a couple of clay minerals in the pedon suggested that the soils in Abakaliki have developed under the significant influence of aeolian dust delivered by the Harmattan. The findings might describe a site-specific deposition pattern of Harmattan dusts as well as hydromorphic soil-forming processes in the wetlands of the inland valleys.

Morphogenesis of Vertisols：A Model Study

Studies on Vertisols of Southwest China show that the distribution of organic matter, mechanicalcomposition, carbonates and spore-pollen in their profiles exhibits a definite differentiation and the radiocarbon age has a functional variation with soil depth, which suggests that pedoturbation model is a kind of incomplete model for genetic study and that the disturbance and inversion of solums of Vertisol are not as rapid and absolute as expected. In further consideration of the characters of swelling pressure and shear strength of Vertisol, vertic soil and other zonal soils, it is speculated that soil mechanics model is more adaptable for interpreting the morphogenesis of Vertisols without any contradiction with soil properties.

Organochlorine pesticides in soils from the Issyk-Kul region in the western Tian Shan Mountains,Kyrgyzstan：Implication for spatial distribution,source apportionment and ecological risk assessment

As organchlorine pesticides(OCPs) may be an ecologic threat to mountain environments due to their tendency to deposit and accumulate in mountain regions undergoing long-range air transport, OCPs were analyzed in soils collected from an intermontane basin of the western Tian Shan Mountains, which is the UNESCO protected natural reserve of Issyk-Kul. Total OCP concentrations in the Issyk-Kul region ranged from 4.63 to 414 ng/g dw, of which two extraordinary high OCP concentrations(414 ng/g dw and 213 ng/g dw, respectively) influenced by an abandoned dumping site and urban sewage, respectively, were found. Principal component analysis(PCA) and correlation analysis inferred that the OCP inputs in the east of the Issyk-Kul region were mainly from local endogenous sources, and exogenous input via LRAT processes were prominent in the west and south. Additionally, the isomeric and parent substance/metabolite ratios revealed most pesticides accumulated in this region were from old usage, while DDTs had fresh input because of possibly illegal regional application and a slow degradation from the dumping site. Furthermore, ecological risk assessment revealed that no frequently adverse ecological effects were observed in the Issyk-Kul region, but potential risks on neighbouring organisms induced by p,p'-DDT and γ-HCH in dumping site and urban sewage should be considered when devising an efficient management plan to prevent secondary pollution.

Modeling for Volatilization and Bioremediation of Toluene-contaminated Soil by Bioventing

A two-dimensional numerical model is developed to simulate the flow,transport and biodegradation of toluene during bioventing （BV） processes in the unsaturated zones.The simulation for a single well BV system is used to illustrate the effect of air injection rate on remediation efficiency.The air is injected into the vadose zone to create a positive pressure.Simulation results show that air injection rate is a primary parameter governing the dispersal,redistribution and surface loss of contaminant.At injection rates of 81.504 m3·d-1 （Run 1） and 407.52 m3·d-1 （Run 2）,the total removed mass of toluene is 169.14 kg and 170.59 kg respectively.Ratios of volatilization to bio-degradation in Run 1 and Run 2 are 0.57︰1 and 0.89︰1,respectively,indicating that lower air injection rate enhances the biodegradation efficiency greatly.Air injection rate should be optimized to meet oxygen demand and to minimize the operational cost.

Vascular plants distribution in relation to topography and environmental variables in alpine zone of Kedarnath Wild Life Sanctuary,West Himalaya

The present study was carried out in Tungnath alpine meadows of Kedarnath Wild Life Sanctuary, Western Himalaya from subalpine to upper alpine zone. A total of four summits were selected along an altitudinal gradient and sampled for detailed vegetation analysis using multi summit approach as per Global observation research initiative in alpine environments(GLORIA). Species richness, diversity, and evenness among four summits as well as the interaction between environmental variables with plant communities were assessed. Monthly mean soil temperature was calculated using data retrieved from geo-precision temperature logger in order to identify the trend of soil temperature among different season and altitudinal gradient and its implications to plant communities. Soil samples were analyzed fromeach summit by collecting randomized composite soil samples. The indirect non-metric multidimensional scaling(NMDS) and direct canonical correspondence analysis(CCA) tools of ordination techniques to determine the linkage between plant species from various sample summits and biotic/abiotic environmental gradients were used in the present study. The results of the study demonstrated increase in species richness as soil temperature increases, the ecotone representing summits were found most warm summits followed by highest species richness. Annual soil temperature increased by 1.43°C at timberline ecotone. Whereas, at upper alpine zone the soil temperature increased by 0.810 C from year 2015 to 2016. S?rensen's similarity index was found to be increased between subalpine and upper alpine zone with increase in the presence of subalpine plant species at upper alpine zone. Both the ordination tools separate the subalpine summit and their respective vegetation from summits representingtimberline ecotone and upper alpine zone. Soil p H, altitude, soil cation exchange capacity were found as the key abiotic drivers for distribution of plant species.

Effects of Humus Fertilizer from Fermented Branches on Microorganisms and Enzyme Activity in the Soil under Dracontomelon duperreranum Trees

[Objective] This study aimed to explore the effect of humus fertilizer from fermented branches on pH, total porosity, contents of organic matter, alkaline hy- drolysable nitrogen, available phosphorus, rapidly available potassium, the number of microorganisms and the activity of enzymes in the soil under Dracontomelon duper- reranum trees. [Method] Experiments were carried out to study the physical and chemical properties of soil under Dracontomelon duperreranum trees, and soil with- out any fertilizer treatment was used as control. [Result] The results showed that application of humus fertilizer from fermented branches raised the total porosity of soil, and improved the contents of soil organic matter, available phosphorus, rapidly available potassium, the number of soil microorganisms and the activity of soil en- zymes. In addition, the number of soil microorganisms was positively related to the activity of soil enzymes. [Conclusion] Application of humus fertilizer from fermented branches markedly raised the ratio of the number of bacteria to the number of fungi, and promoted the transformation of fungi-rich soil into bacteria-rich soil, which thus significantly enhanced the soil fertility and improved the soil environment under Dracontomelon duperreranum trees.

Nymphaeaceae Salisb. and Trapaceae Dumort. Families in the Collection of O.V. Fomina Botanical Garden

On basis of aquatic and riverside-aquatic plants collection of O.V. fomina botanical garden is conducted research of ontogenesis, ecology, phenology, carpogenesis, biomorphology, life forms, adaptatations, of this group＇s plants, peculiarities of their cultivation and application in conditions of temperate zone of Ukraine. Special values in research have ancient genera and species, which include representatives ofNymphaeaceae salisb, and trapaceae Dumort. families, 22 species, 6 varieties, 1 hybrid, 30 cultivars of which are presented in collection of garden in open and covered soil. For the first time in covered soil of two conservatories ecological modeling was conducted. Placement of plants is done in form of 5 models of artificial ecotopes, in 155 abatises. Four ecobiomorphological groups based on rhizome system were determined for Nymphaeaceae, among which conditionally-rhizome and conditionally-stolone are provided for the first time.

Rehabilitation Soils with Date Palm Mulching Treatments

Kuwait is located in hyper arid desert environment. This geographical location and irrational human activities accelerate the expansion of land degradation problem. In order to rehabilitate the degraded areas it is necessary to use soil and water resources in sustainable manner. Owing to these reasons it is essential to use appropriate methods based on the scientific diagnostics of the problem. It is compulsory to identify, specify and test different efficient, cost-effective and environment friendly sound sustainable sand control measures such as, semi-circular bunds, square micro catchment and checker board palm leaves to rehabilitate degraded lands in Liyah refilled quarries. To evaluate the impact of rehabilitation method through mulching with date palm leaves soil samples were collected （control and rehabilitation sites with square micro catchment） prior to the implementation plan and post completion of the project （three years）. In this study will be highlighted on detail the results of using square micro catchment and with short brief descriptions on other water harvesting techniques. The results showed an improvement of physical soil properties after the application of these techniques. Soil fertility increased through increasing the quantity of fine and very fine sand. The soil moisture at the surface soil increased from 0.085% to 1.62% after the treatment. The untreated soil has high bulk density about 2 g/cm3 and low porosity about 27%. However, after the soil was ploughed and mulched the bulk density decreased to 0.03 g/cm3. And porosity improved 98%. This study conserved the irrigation water through reducing the proportion of soil evaporation, in addition to the creation of optimum condition for plant growth. The aim of this study was to analyze the effect of using organic mulch date palm leaves with water harvesting techniques on the physical and biological properties of degraded soil in Liyah area.

Determination of Hg in soil by ultrasonic slurry sampling hydride generation atomic fluorescence spectrometry

Ultrasonic aided slurry sampling hydride generation atomic fluorescence spectrometry （USS-HG-AFS） was developed for the determination of Hg in soil samples from a sewage-irrigated farm. 500 mg grounded soil was suspended in agar solution by an ultrasound water bath before the HG-AFS determination. The results for the reference material of soil （serial number GBW-07411） agreed satisfactorily with the certified values. Results obtained by the developed procedure compared well with those after traditional acid digestion of samples. The detection limit are 6.7ngL-1 for Hg respectively, with average relative standard deviation values of 6.4% for analysis of a series of soil samples of different origin. The recoveries of the anatytes varied in the range from 95 to 107%. This observation has stimulated interest in fast, accurate and sensitive analytical methods for determination of metals in soil.

Biochar Effect on Water Evaporation and Hydraulic Conductivity in Sandy Soil

Biochar, as a kind of soil amendment, has important effects on soil water retention. In this research, 4 different kinds of biochars were used to investigate their influences on hydraulic properties and water evaporation in a sandy soil from Hebei Province, China. Biochar had strong absorption ability in the sandy soil. The ratio of water content in the biochar to that in the sandy soil was less than the corresponding ratio of porosity. Because of the different hydraulic properties between the sandy soil and the biochar, the saturated hydraulic conductivity of the sandy soil gradually decreased with the increasing biochar addition. The biochar with larger pore volume and average pore diameter had better water retention. More water was retained in the sandy soil when the biochar was added in a single layer, but not when the biochar was uniformly mixed with soil. Particle size of the added biochar had a significant influence on the hydraulic properties of the mixture of sand and biochar. Grinding the biochar into powder destroyed the pore structure, which simultaneously reduced the water absorption ability and hydraulic conductivity of the biochar. For this reason, adding biochar powder to the sandy soil would not decrease the water evaporation loss of the soil itself.

Effects of mosaic biological soil crusts on vascular plant establishment in a coastal saline land of the Yellow River Delta, China

Aims The effects of biocrusts on vascular plants are rarely evaluated in coastal saline lands.Our aim was to examine whether and how a mosaic of biocrusts affect seed germination of two typical herbaceous plants in a coastal saline land of the Yellow River Delta,to enhance our understanding by which substrate heterogeneity influences plant community dynamics.Methods We conducted growth chamber experiments to investigate the effects of biocrusts and uncrusted soil from bare patch-,Phragmites australis-,Suaeda glauca-and Tamarix chinensis-dominated habitats on seed germination percentage and mean germination time of two herbaceous plants:the perennial P.australis and the annual S.glauca.We also explored the mechanisms underlying the effects of substrate on seed germination.Important Findings Compared with uncrusted soil,biocrusts increased water content,nutrient accumulation and concentration of most salt ions,but they reduced soil pH value.Biocrusts with mosses directly decreased soil pH value and concentration of Mg2+,resulting in an indirect increase in seed germination percentage of S.glaucas.The low soil pH value also resulted in an indirect decrease in seed germination speed of P.australis in their own habitats.Bare patch directly increased accumulation of Cl?,resulting in an indirect decrease in seed germination speed of P.australis.These results suggest that biocrusts with mosses in P.australis habitats offer a window of opportunity for germination of S.glaucas.Biocrusts combined with habitat type have the potential to influence plant community structure through an effect on seed germination and establishment.

Biochar for Sustainable Soil Health:A Review of Prospects and Concerns

Biochar as a soil amendment is confronted with the challenge that it must benefit soil health as it can be by no means separated from soils once it is added. The available literature even though sparse and mostly based on short-term studies has been encouraging and the trend obtained so far has raised many hopes. Biochar has been reported to positively impact an array of soil processes ranging from benefiting soil biology, controlling soil-borne pathogens, enhancing nitrogen fixation, improving soil physical and chemical properties,decreasing nitrate(NO-3) leaching and nitrous oxide(N2O) emission to remediation of contaminated soils. However, very little biochar is still utilized as soil amendment mainly because these benefits are yet to be quantified, and also the mechanisms by which the soil health is improved are poorly understood. Due to the infancy of research regarding this subject, there are still more questions than answers. The future research efforts must focus on carrying out long-term experiments and uncover the mechanisms underlying these processes so that key concerns surrounding the use of biochar are addressed before its large scale application is recommended.

A distributed scheme developed for eco-hydrological modeling in the upper Heihe River

Modeling the hydrological processes at catchment scale requires a flexible distributed scheme to represent the catchment to- pography, river network and vegetation pattern. This study has developed a distributed scheme for eco-hydrological simulation in the upper Heihe River. Based on a 1 km x 1 km grid system, the study catchment is divided into 461 sub-catchments, whose main streams form the streamflow pathway. Furthermore, a 1 km grid is represented by a number of topographically similar ＂hillslope-valley＂ systems, and the hillslope is the basic unit of the eco-hydrological simulation. This model is tested with a simplified hydrological simulation focusing on soil-water dynamics and streamflow routing. Based on a 12-year simulation from 2001 to 2012, it is found that variability in hydrological behavior is closely associated with climatic and landscape condi- tions especially vegetation types. The subsurface and groundwater flows dominate the total river runoff. This implies that the soil freezing and thawing process would significantly influence the runoff generation in the upper Heihe basin. Furthermore, the runoff components and water balance characteristics vary among different vegetation types, showing the importance of coupling the vegetation pattern into catchment hydrological simulation. This paper also discusses the model improvement to be done in future study.

Factors Affecting the Performance of Single-Chamber Soil Microbial Fuel Cells for Power Generation

There is limited information about the factors that affect the power generation of single-chamber microbial fuel cells （MFCs） using soil organic matter as a fuel source. We examined the effect of soil and water depths, and temperature on the performance of soil MFCs with anode being embedded in the flooded soil and cathode in the overlaying water. Results showed that the MFC with 5 cm deep soil and 3 cm overlaying water exhibited the highest open circuit voltage of 562 mV and a power density of 0.72 mW m-2. The ohmic resistance increased with more soil and water. The polarization resistance of cathode increased with more soil while that of anode increased with more water. During the 30 d operation, the cell voltage positively correlated with temperature and reached a maximum of 162 mV with a 500 ft external load. After the operation, the bacterial 16S rRNA gene from the soil and anode was sequenced. The bacteria in the soil were more diverse than those adhere to the anode where the bacteria were mainly affiliated to Eseherichia coli and Deltaproteobacteria. In summary, the two bacterial groups may generate electricity and the electrical properties were affected by temperature and the depth of soil and water.

Plant Growth-Promoting Traits in Rhizobacteria of Heavy Metal-Resistant Plants and Their Effects on Brassica nigra Seed Germination

Phytoremediation is an emerging technology that uses plants and their associated microbes to clean up pollutants from the soil, water, and air. In order to select the plant growth-promoting rhizobacteria （PGPR） for phytoremediation of heavy metal contamination, 60 bacterial strains were isolated from the rhizosphere of two endemic plants, Prosopis laevigata and Spharealcea angustifolia, in a heavy metal-contaminated zone in Mexico. These rhizobacterial strains were characterized for the growth at different pH and salinity, extracellular enzyme production, solubilization of phosphate, heavy metal resistance, and plant growth-promoting （PGP） traits, including production of siderophores and indol-3-acetic acid （IAA）. Overall, the obtained rhizobacteria presented multiple PGP traits. These rhizoba^teria were also resistant to high levels of heavy metals （including As as a metalloid） （up to 480 mmol L-1 As（V）, 24 mmol L-1 Pb（II）, 21 mmol L-1 Cu（II）, and 4.5 mmol L-1 Zn（II））. Seven rhizobacterial strains with the best PGP traits were identified as members of Alcaligenes, Bacillus, Curtobacterium, and Microbacterium, and were selected for further bioassay. The inoculation of Brassica nigra seeds with Microbacteriurn sp. CE3R2, Microbacterium sp. NE1R5, Curtobacterium sp. NM1R1, and Microbacterium sp. NM3E9 facilitated the root development; they significantly improved the B. nigra seed germination and root growth in the presence of heavy metals such as 2.2 mmol L-1 Zn（II）. The rhizobacterial strains isolated in the present study had the potential to be used as efficient bioinoculants in phytorremediation of soils contaminated with multiple heavy metals.