South Mountain Research Articles

Meteorological, snow, streamflow, topographic, and vegetation height data from four western juniper-dominated experimental catchments in southwestern Idaho, USA

Abstract. Meteorological, snow, streamflow, topographic, and vegetation height data are presented from the South Mountain experimental catchments. This study site was established in 2007 as a collaborative, long-term research laboratory to address the impacts of western juniper encroachment and woodland treatments in the interior Great Basin region of the western USA. The data provide detailed information on the weather and hydrologic response from four highly instrumented catchments in the late stages of woodland encroachment in a sagebrush steppe landscape. Hourly data from six meteorologic stations and four weirs have been carefully processed, quality-checked, and are serially complete. These data are ideal for hydrologic, ecosystem, and biogeochemical modeling. Data presented are publicly available from the USDA National Agricultural Library administered by the Agricultural Research Service (https://data.nal.usda.gov/dataset/data-weather-snow-and-streamflow-data-four-western-juniper-dominated-experimental-catchments, doi:10.15482/USDA.ADC/1254010).

Mountain Waves, Downslope Winds, and Low-Level Blocking Forced by a Midlatitude Cyclone Encountering an Isolated Ridge

Abstract The interaction of a midlatitude cyclone with an isolated north–south mountain barrier is examined using numerical simulation. A prototypical cyclone develops from an isolated disturbance in a baroclinically unstable shear flow upstream of the ridge, producing a cold front that interacts strongly with the topography. The structure and evolution of the lee waves launched by the topography are analyzed, including their temporal and their north–south variation along the ridge. Typical mountain wave patterns are generated by a 500-m-high mountain, but these waves often exhibit significant differences from the waves produced in 2D or 3D simulations with steady large-scale-flow structures corresponding to the instantaneous conditions over the mountain in the evolving flow. When the mountain height is 2 km, substantial wave breaking occurs, both at low levels in the lee and in the lower stratosphere. Despite the north–south uniformity of the terrain profile, large north–south variations are apparent in wave structure and downslope winds. In particular, for a 24-h period beginning after the cold front passes the upstream side of the ridge toward the south, strong downslope winds occur only in the northern half of the lee of the ridge. Just prior to this period, the movement of the cold front across the northern lee slopes is complex and accompanied by a burst of strong downslope winds and intense vertical velocities.

The dynamics of contemporary glaciers in the mountains of the south of East Siberia.

The dynamics of contemporary glaciers in the mountains of the south of East Siberia.

浙江省区域经济发展差异及影响因素分析

从1978年至今，浙江省成为东部沿海发达地区，在经济发展方面取得了巨大成就，各区域之间的差异也开始发生变化。本文主要从协调发展浙江区域经济的角度出发，首先对浙江区域经济差异从80年代以来的变化分析得出，无论是从环杭州湾地区、浙中与东南沿海地区、浙西南山区这三大区域中，还是从省内的11个市域来看，它们之间的绝对差异都在不断扩大，相对差异也在总体上不断扩大。之后，将选用的指标与浙江省整体经济发展水平(人均GDP)的相关关系进行检验，发现人均城乡居民储蓄存款、人均固定资产投资、人均城乡居民社会消费品零售总额、人均农林牧渔业总产值、人均工业总产值及公路客运量对人均GDP增长有显著促进作用。 Since 1978, Zhejiang has become a developed area in the east coast, with great achievements in economic development, and the differences between regions have begun to change. This article is mainly from the perspective of the coordinated development of regional economy in Zhejiang, the first since the 80s of Zhejiang regional economic difference change analysis, both in terms of the ring of the Hangzhou bay region, and southeast coastal area of middle of Zhejiang, Zhejiang south mountain district in the three areas, or from the province’s 11 district, the absolute difference between them is growing, the relative difference is also expanding on the whole. We will choose indicators and overall level of economic development in Zhejiang province (the GDP) correlation test, and find that urban and rural residents per capita savings deposits of urban and rural residents per capita, per capita investment in fixed assets, total retail sales of social consumer goods, animal husbandry fishery output per capita, per capita gross industrial output value and the highway passenger quantity significant promoting effect on growth of GDP per capita.

Assessment of Beshagard Mountain Tectonic Activity (South of Jazmurian Depration) Application IRAT Index

Morphometry status of tectonic active areas around the Beshagard mountain is as a result of the interaction of neotectonic movements, erosion and subsidence processes. Bashagard mountain contains two attached mountains (GhaleTohi imountain and Bashagard mountain) with an altitude of 2000 meters at the south of the Jazmurian subsidence surrounded by Quaternary and Neogene. The boundary between the north Makran and Jazmurian subsidence is a fault that located between Band-e-Ziarat unit and western alluvial fan and units of Ganj, Mokhtarabad and Rameshk in the south. Tectonic activity has a significant impact on their morphometry status and drainage basin system. We studied geomorphological patterns of drainage and mountain fronts features for clear changes and high style of mountain. In this study, we studied seven geomorphological indicators for each basin including Vf, Bs, Smf, Sl, Af, RA, Hi between west and south mountain front of Jazmurian. Morphometric indexes were divided in three categories. The average of seven indicators is an index of relative tectonic activity (IRAT). The level of tectonic activity of each IRAT category was determined. Finally, tectonic activity was evaluated for each drainage basin. Results show good similarity between IRAT category and ratio of tectonic activity of the number of drainage basins. The streams profile shows the uplift movement in the western part of subsidence Jazmurian. Thus, the achievements obtained from the analysis of topographic indices, the region’s river system and geomorphological evidence show the movements of uplift and movement of right-lateral strike-slip of Jiroft fault in the west and reverse faulting of Kranj and Jazmurian faults at east of subsidence Jazmurian that all indicates the diagonal tectonic movements.

New Records of Reptiles on the Red Sea Coast, Egypt, with Notes on Zoogeography

New records of 20 reptile species and subspecies on the Red Sea coast of Sinai Peninsula and Eastern Desert in Egypt are given. A zoogeographical analyses of the herpetofauna and comparison of the species compositions results to estimate the biodiversity for each subregion of Eastern Egypt. The faunal richness, taxonomic diversity and endemism level in hyperarid deserts of the Egypt are discussed. Mountainous South Sinai and southern part of the South Eastern Desert is suggested to consider as biodiversity hotspots in Eastern Egypt.

New Records of Reptiles on the Red Sea Coast, Egypt, with Notes on Zoogeography

New records of 20 reptile species and subspecies on the Red Sea coast of Sinai Peninsula and Eastern Desert in Egypt are given. A zoogeographical analyses of the herpetofauna and comparison of the species compositions results to estimate the biodiversity for each subregion of Eastern Egypt. The faunal richness, taxonomic diversity and endemism level in hyperarid deserts of the Egypt are discussed. Mountainous South Sinai and southern part of the South Eastern Desert is suggested to consider as biodiversity hotspots in Eastern Egypt.

The Ascent of the Artist in Ernest Buckler’s The Mountain and the Valley (1952)

With his first novel, The Mountain and the Valley (1952), Canadian writer Ernest Buckler chose to stay true to the longstanding tradition of the Künstlerroman, best illustrated by one of the greatest modernist writers of the twentieth century, James Joyce and his A Portrait of the Artist as a Young Man (1916). Like Joyce who chose to revisit the genre, Buckler decided to write about the throes of a young artist who seeks to escape from tradition and life in the country. The Mountain and the Valley relates the intellectual coming of age of David Canaan, a young character whose artistic sensitivity sets him apart from the rest of his community in the Annapolis Valley, a valley in the Nova Scotian hinterland of Canada. The story is set in the small town of Entremont which, as its very name suggests, is surrounded by two mountains that isolate and confine the characters to a life of routine and deny them access to time and progress. The North and South Mountains do not merely enclose the characters in the seasonal life of the farmer, they frame the narrative of David Canaan that begins and concludes with the ascent of the South Mountain where he dies prematurely at the age of thirty. This article will study the relationship between the image of the mountain, the plotline and the very act of writing itself as a creative process that the writer constantly interrogates. Is writing the only way to represent the emergence and uniqueness of a writer who is awakening to his own consciousness? I will try to explain how the mountain not only shapes the novel, but also a text made salient through contact with a seeming monolithic mountain. As a result, salience will be understood as the emphasis laid on the artist’s awakening, an awakening that cannot be studied separately from the geographical space the protagonist inhabits. Relief-related discourse will inevitably lead to discourse related to the awakening to one’s own consciousness.

Identification of debris-flow hazards in warm deserts through analyzing past occurrences: Case study in South Mountain, Sonoran Desert, USA

After recognition that debris flows co-occur with human activities, the next step in a hazards analysis involves estimating debris-flow probability. Prior research published in this journal in 2010 used varnish microlamination (VML) dating to determine a minimum occurrence of 5 flows per century over the last 8100years in a small mountain range of South Mountain adjacent to neighborhoods of Phoenix, Arizona. This analysis led to the conclusion that debris flows originating in small mountain ranges in arid regions like the Sonoran Desert could pose a hazard. Two major precipitation events in the summer of 2014 generated 35 debris flows in the same study area of South Mountain—providing support for the importance of probability analysis as a key step in a hazards analysis in warm desert settings. Two distinct mechanisms generated the 2014 debris flows: intense precipitation on steep slopes in the first storm; and a firehose effect whereby runoff from the second storm was funneled rapidly by cleaned-out debris-flow chutes to remobilize Pleistocene debris-flow deposits. When compared to a global database on debris flows, the 2014 storms were among the most intense to generate desert debris flows — indicating that storms of lesser intensity are capable of generating debris flows in warm desert settings. The 87Sr/86Sr analyses of fines and clasts in South Mountain debris flows of different ages reveal that desert dust supplies the fines. Thus, wetter climatic periods of intense rock decay are not needed to resupply desert slopes with fines; instead, a combination of dust deposition supplying fines and dirt cracking generating coarse clasts can re-arm chutes in a warm desert setting with abundant dust.

Numerical simulation of the impact of reforestation on winter meteorology and environment in a semi-arid urban valley, Northwestern China

Since 1999 Chinese government has made great effort to reforest the south and north mountains surrounding urban Lanzhou – a city located in a river valley, Northwestern China. Until 2009 obvious land use change occurred, with 69.2% of the reforested area been changed from grasslands, croplands, barren or sparsely vegetated land to closed shrublands and 20.6% from closed shrublands, grasslands, and croplands to forests. Reforestation changes land-surface properties, with possible impact on the evolution of atmospheric variables. To understand to what extent the local meteorology and environment could be affected by reforestation in winter, and through what processes, two sets of simulations were conducted using the Weather Research and Forecasting model (WRF) and the FLEXible PARTicle (FLEXPART) dispersion model for a control case with high-resolution remotely sensed land cover data for 2009 and a scenario assuming no reforestation since 1999. Results suggested that the changes in albedo, surface exchange coefficient and surface soil heat conductivity related to reforestation led to the changes in surface net radiation and surface energy partitioning, which in turn affected the meteorological fields and enhanced the mountain-valley wind circulation. Replacement of shrublands and grassland with forest in the south mountain through reforestation play a dominant role in the enhancement of mountain-valley wind circulation. Reforestation increased the amount of air exchanged between the valley and the outside during the day, with the largest hourly increase of 10% on calm weather days and a monthly mean hourly increase of 2% for the study period (Dec. 2009). Reforestation affected the spatial distribution of pollutants and slightly improved the urban air quality, especially in the eastern valley. Results from this study provide useful information for future urban air quality management and reforestation plan, and some experience for cities with similar situations in the world.

Fluxo das águas subterrâneas em um aquífero carbonático ‘subajustado’ em clima semiárido: aplicação de traçadores ambientais para a Bacia Salt, Novo México (EUA)

The Salt Basin is a semiarid hydrologically closed drainage basin in southern New Mexico, USA. The aquifers in the basin consist largely of Permian limestone and dolomite. Groundwater flows from the high elevations (∼2,500 m) of the Sacramento Mountains south into the Salt Lakes, which are saline playas. The aquifer is ‘underfit’ in the sense that depths to groundwater are great (∼300 m), implying that the aquifer could transmit much more water than it does. In this study, it is speculated that this characteristic is a result of a geologically recent reduction in recharge due to warming and drying at the end of the last glacial period. Water use is currently limited, but the basin has been proposed for large-scale groundwater extraction and export projects. Wells in the basin are of limited utility for hydraulic testing; therefore, the study focused on environmental tracers (major-ion geochemistry, stable isotopes of O, H, and C, and 14C dating) for basin analysis. The groundwater evolves from a Ca–HCO3 type water into a Ca–Mg (Na) – HCO3–Mg (Cl) water as it flows toward the center of the basin due to dedolomitization driven by gypsum dissolution. Carbon-14 ages corrected for dedolomitization ranged from less than 1,000 years in the recharge area to 19,000 years near the basin center. Stable isotopes are consistent with the presence of glacial-period recharge that is much less evaporated than modern. This supports the hypothesis that the underfit nature of the aquifer is a result of a geologically recent reduction in recharge.

Composition of sediment records late Quaternary paleogeographic evolution of Santa Clara Valley, California

Gravel and sand samples from alluvium in five wells in the Santa Clara Valley, California (USA), have particle compositions that help constrain patterns of Quaternary basin evolution and sediment dispersal within the valley. Samples were collected from depths as great as 307 m, and paleomagnetic results obtained by other workers suggest that the sediment sampled ranges in age to ca. 800 ka. The gravel contains common to abundant Mesozoic graywacke and metavolcanic rocks; less common clast types indicate derivation from other Mesozoic rocks. Clasts having lithologies that match Cenozoic source rocks are minor in amount. The abundance of metavolcanic rocks, as well as serpentinite, blueschist, and eclogite, among the less common gravel clasts, generally increases with depth in each well. Sand samples contain a variety of mostly metamorphic heavy minerals, including some distinctive blueschist facies minerals. Blue amphibole and chrome spinel are rare to common in the sand, and their abundance also increases with depth. The most useful clasts for determining the location of the sediment source are the metavolcanic rocks and some of the less common clasts. Metavolcanic rocks, common in modern outcrops only in the Santa Cruz Mountains south and west of the Santa Clara Valley, also are common in the gravel. In contrast, with only a few exceptions at shallow levels in the northeasternmost wells, distinctive gravel clasts with sources east of the valley are nearly absent. These observations suggest that most of the sediment was derived from the south and west. Thus, the topographic asymmetry of the valley, with its modern axial drainage east of the valley center, evidently has persisted for at least the past 800 k.y. The increased abundance of pebbles of serpentinite, blueschist, and eclogite and of sand-sized particles of blue amphibole and chrome spinel with depth suggests a change in source through time. The source for these clasts in the deeper levels, and perhaps also some of the metavolcanic clasts, evidently was a basement high within the valley that was gradually buried as the basin filled with sediment. The gravel in the wells has a composition different from that of any previously described outcrops of Pliocene and Pleistocene nonmarine gravels, including the Santa Clara Formation, exposed around the margins of the Santa Clara Valley. This difference suggests that the Santa Clara Formation and similar units are not present in the parts of the valley penetrated by the wells.

Reflecting on heritage and power: dynamics, strategies and appropriations in the Catalan Pyrenees and the French Alps

In this article we will explore the way in which different agents appropriate and use heritage to compete in specific power scenarios. We approach heritage discourses and practices as defining specific political arenas within which power relations are reconfigured. The protection of spaces and places as well as the processes of patrimonialisation that take place inside specific localities give rise to the emergence of new ways of exercising power. We will examine two ethnographic cases from South European mountain areas: the Parc National des Écrins in the French Alps and a Romanesque church in the Catalan Pyrenees. An analysis of both the protected area and the constructed heritage will enable us to focus on heritage as being produced, identified and valued within specific logics and value systems. We examine the dynamics that heritage and heritage policies produce in each context as well as the interest they promote. Heritage both organises different fields of forces and is appropriated by politicians, experts, and economic actors. We will discuss the entanglements, forces and dynamics that are activated and played out as a result of heritage processes in the larger process of contemporary political transformations.

Constraining tectonic compression processes by reservoir pressure evolution: Overpressure generation and evolution in the Kelasu Thrust Belt of Kuqa Foreland Basin, NW China

The Kuqa Foreland Basin (KFB) immediately south of the South Tianshan Mountains is a major hydrocarbon producing basin in west China. The Kelasu Thrust Belt in the basin is the most favorable zone for hydrocarbon accumulations. Widespread overpressures are present in both the Cretaceous and Paleogene reservoirs with pressure coefficients up to 2.1. The tectonic compression process in KFB resulted from the South Tianshan Mountains uplift is examined from the viewpoint of the overpressure generation and evolution in the Kelasu Thrust Belt. The overpressure evolution in the reservoir sandstones were reconstructed through fluid inclusion analysis combined with PVT and basin modeling. Overpressures at present day in the mudstone units in the Kelasu Thrust Belt and reservoir sandstones of the Dabei Gas Field and the Keshen zone are believed to have been generated by horizontal tectonic compression. Both disequilibrium compaction and horizontal tectonic compression are thought to contribute to the overpressure development at present day in the reservoir of the Kela-2 Gas Field with the reservoir sandstones showing anomalously high primary porosities and low densities from wireline log and core data. The overpressure evolution for the Cretaceous reservoir sandstone in the Kelasu Thrust Belt evolved through four stages: a normal hydrostatic pressure (>12–5 Ma), a rapidly increasing overpressure (∼5–3 Ma), an overpressure release (∼3–1.64 Ma) and overpressure preservation (∼1.64–0 Ma). Overpressure developed in the second stage (∼5–3 Ma) was generated by disequilibrium compaction as tectonic compression due to the uplift of the Tianshan Mountains acted at the northern monocline of KFB from 5 Ma to 3 Ma, which provided abundant sediments for the KFB and caused the anomalously high sedimentation rate during the N2k deposition. From 3 Ma to 1.64 Ma, the action of tectonic compression extended from the northern monocline to the Kelasu Thrust Belt and returned to the northern monocline of KFB from 1.64 Ma to present day. Therefore, the horizontal tectonic compression was the dominant overpressure mechanism for the overpressure generation in the third stage (∼3–1.64 Ma) and overpressure caused by disequilibrium compaction from 5 Ma to 3 Ma was only preserved in the Kela-2 Gas Field until present day.

Hurricane Camille 1969 and Storm-Triggered Landslides in the Appalachians and a Perspective in a Warmer Climate

This study analyzes storm-triggered landslides in the US Appalachians, in the current geological setting. Concave valleys that favor the convergence of surface runoff are the primary locales for landslides. If the slopes are weathered to the same degree and have the same vegetation coverage, slope orientation (azimuthal) is not critical for slope stability. However, it is found that for the region south of the Black Mountains (North Carolina), north-facing slopes are more prone to slide, because, for the regions not limited by water availability (annual precipitation), the northern slopes usually are grass slopes. For the slopes of the Blue Ridge Mountains, south facing slopes are more prone to slide. Gravity measurements over the past decade reveal that geological conditions, the chute system and underground cracks over the region are stable. Future changes in storm-triggered landslide frequency are primarily controlled by changes in extreme precipitation. Thus, a series of ensemble climate model experiments is carried out to investigate possible changes in future extreme precipitation events, using a weather model forced by atmospheric perturbations from ensemble climate models. Over 50 locations are identified as prone to future landslides. Many of these locales are natural habitats to the Appalachian salamanders. In a future warmer climate, more severe extreme precipitation events are projected because of increased atmospheric water vapor and more frequent passages of tropical cyclone remnants. There is also a likely shift of tropical cyclone tracks and associated extreme precipitations, and the cluster center of Appalachians’s scarps is expected to move westward, with ecological consequences for the endemic salamanders.

间作栽培对连作马铃薯根际土壤微生物群落的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 间作栽培对连作马铃薯根际土壤微生物群落的影响 DOI: 10.5846/stxb201412072425 作者: 作者单位: 宁夏大学农学院 银川 750021, 宁夏大学农学院 银川 750021, 宁夏大学农学院 银川 750021, 宁夏大学农学院 银川 750021, 宁夏大学农学院 银川 750021, 宁夏大学农学院 银川 750021, 宁夏大学农学院 银川 750021 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(31160104);国家"十二五"科技支撑计划课题(2011BAD29B07) Effects of intercropping on soil microbial communities after long-term potato monoculture Author: Affiliation: School of Agriculture,Ningxia University,School of Agriculture,Ningxia University,School of Agriculture,Ningxia University,School of Agriculture,Ningxia University,School of Agriculture,Ningxia University,School of Agriculture,Ningxia University,School of Agriculture,Ningxia University 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:连作严重影响了作物的产量和品质,而土壤微生物群落结构与功能对土壤生态系统和植物健康至关重要。以连作10a土壤为基质,单作马铃薯为对照,采用磷脂脂肪酸(Phospholipid fatty acids)、BIOLOGA技术和真菌形态学鉴定方法,研究了玉米、蚕豆与马铃薯间作模式下土壤微生物群落结构、功能和丛植菌根(Arbuscular Mycorrhizal)真菌对土壤环境变化的响应。结果表明:间作调控下,马铃薯根际土壤微生物主要类群结构发生显著改变;玉米间作马铃薯,土壤微生物群落总生物量降低,但群落功能多样性提高,促进了以羧酸类、多聚化合物、芳香类化合物、氨基酸类化合物为碳源的微生物类群代谢活性增强;蚕豆间作增加了土壤微生物总生物量,仅促进了以碳水化合物为碳源的微生物类群代谢活性。间作改变了作物根际土壤AM真菌的种、属数,AM真菌多样性降低,优势种由明球囊霉、地球囊霉转变为玉米间作体系里的福摩萨球囊霉、球泡球囊霉;蚕豆间作体系里福摩萨球囊霉和疣状无梗囊霉是优势种。间作栽培下AM真菌优势种群的变化可能受植物间的共生关系、微生物结构与功能等因素的制约。间作条件下,玉米显著影响了马铃薯根际土壤微生物群落功能多样性,而蚕豆则显著改变了微生物群落结构多样性;玉米、蚕豆对马铃薯根际土壤微生物群落功能与结构变化的影响不同步;间作调控后持续的土壤微生物群落结构与功能观察才有助于解释土壤微生物结构变化引起的功能响应。 Abstract:Soil microorganisms are one of the main components of the soil ecosystem and play an important role in agro-ecosystem function and sustainable agricultural development. Arbuscular mycorrhizal fungi (AMF) are important components of soil microbial communities because of their symbiotic relationships with many crop species. The increase in potato production area in the south mountain region of Ningxia, China, made crop rotation difficult and long-term potato monoculture led to significant yield reductions due to pests and devastating diseases. Plant complementarity may decrease interspecific competition through resource partitioning, and facilitation may improve the availability of resources. AMF seem to play an important role in these interactions, so intercropping potatoes with a different crop species and AMF may moderate yield reductions in a long-term potato monoculture system. The objective of this study was to investigate soil microbial community composition and the changes in AMF diversity due to the transition from continuous potato monoculture to an intercropping system. We studied two different intercropping systems, maize-potato and faba bean-potato, in a field where a potato monoculture system had been applied continuously for 10 a. The composition and the functional diversity of soil microbial communities were accessed by measuring the phospholipid fatty acids contents (PLFA) and by community level physiological profiles (CLPPs) using the Eco-plate technique. Then we identified AMF by morphological characteristics and calculated their relative abundance. The results showed that soil microbial community structures changed with the transition from continuous potato monoculture to the intercropping system. In the maize-potato intercropping system, PLFA levels decreased, whereas the metabolic activity of microbial functional groups, as well as the carbon utilization of carboxylic acid, polymer compounds, aromatic compounds, and amino acids, increased. In the faba bean-potato intercropping system, only carbohydrate utilization by microorganisms increased. The total PLFA content was lower in the maize-potato intercropping system than in the faba bean-potato system. The biomasses of gram-negative bacteria, gram-positive bacteria, Pseudomonas, and AMF were lower by 35.1%, 28.0%, 24.8%, and 9.0%, respectively, in the maize-potato intercropping system than in the continuous monoculture system. Conversely, the fungal biomass was higher by 21.1% in the maize-potato intercropping system than in the continuous monoculture system. However, there was a reverse tendency in the faba bean-potato intercropping system. AMF species richness decreased in the continuous monoculture system compared to the faba bean-potato intercropping system, while the dominant species in the latter was Ganoderma formosanum. The change in AMF dominant species might be restricted by some integrated factors, including the symbiotic relationship with different crops and the diversity of soil microorganism structure and function. These results suggest that the performance of soil microbial communities is not always consistent with changes in the structure of soil microbial functional groups in intercropping systems. The maize-potato intercropping system may enhance the diversity of soil microbial functional groups, whereas in the faba bean-potato intercropping system, the diversity of soil microbial functional groups is higher. We may conclude that different microbial species have different rhizosphere effects on potato cultivation. 参考文献 相似文献 引证文献

Evaluating process domains in small arid granitic watersheds: Case study of Pima Wash, South Mountains, Sonoran Desert, USA

This paper provides support for the concept of geomorphic process domains developed by Montgomery (1999) by linking geomorphic processes to ecological variations seen in the Pima arid granitic watershed of the Sonoran Desert, Phoenix, Arizona. Closer joint spacing shows a statistically significant correlation with lower percentages of mineral grain attachment as measured by digital image processing of backscattered electron microscope imagery. Lower mineral grain attachment leads to more frequent spalling of rock surfaces, as measured by varnish microlamination (VML) ages of the last spalling event. In contrast, more distant joint spacing leads to in situ 10Be erosion rates of 3.4–8.5mm/ka and the emergence of low domes and kopje granitic landforms; these low domes also serve as knickpoints along ephemeral washes. Distant jointing thus plays a key role in generating the bare bedrock surfaces that funnel limited precipitation to bedrock margins — enhancing the canopy cover of perennial plants next to the bare bedrock. Joint-influenced geomorphic processes at Pima Wash generate four distinct process domains: (PD1) armored drainage divides; (PD2) slopes with different granite landforms; (PD3) mid- and upper basin channels that mix knickzones, strath floodplains, and sandy alluvial sections; and (PD4) the main ephemeral channel transitioning to the piedmont. Distant jointing promotes bedrock exposure and rock armoring along drainage divides in PD1 that then concentrates runoff and promotes perennial plant growth. More distant joint spacing on slopes in PD2 promotes exposure of granitic bedrock forms that shed overland flow to their margin and promotes flora and fauna growths along the margins of low granitic domes and kopjes. Similarly, wider joint spacing along ephemeral washes in PD3 leads to knickpoints, which in turn act to concentrate moisture immediately downstream. The stream terraces in PD4 influence the ecology through xeric desert pavements on terrace treads and roofs for coyotes (Canis latrans) and gray fox (Urocyon Cinereoargenteus) dens on terrace scarps via stage 3 pedogenic carbonate. These four process domains occur in six other randomly selected granitic watersheds with drainage areas <5km2 in the Mojave and Sonoran Deserts. Results on rates of geomorphic processes in the Pima Wash watershed provide new insight in the desert geomorphology of small granitic watersheds. Catchment-wide denudation rates (CWDRs) recorded by 10Be sampled along the main ephemeral wash vary between 15 and 23mm/ka and do not appear to be influenced by knickpoint or knickzone occurrence; instead slightly lower CWDRs appear to be associated with sediment contributions by subbasins with more abundance of bare bedrock forms. Resampling for CWDR after a 500-year flood event from hurricane moisture at two sites along the main ephemeral channel revealed no detectable changes; this finding confirms the average representativeness of CWDR as a long-term denudation proxy and also means that sediment transport on these arid granitic hillslopes must be incremental and without rapid crest to wash transport. The first reported measurements of incision rates into a small granitic Sonoran Desert watershed, using 10Be and VML, reveal rates on the order of 70–180mm/ka in the lower quarter of Pima Wash for the last 60ka — producing a narrow and deep trench. As this base-level fall propagates upstream, erosion focuses on weaker material with higher joint densities; this facilitates the emergence of domes and kopje landforms with more widely spaced jointing.

Combined effects of wind and solar irradiance on the spatial variation of midday air temperature over a mountainous terrain

When the midday temperature distribution in a mountainous region was estimated using data from a nearby weather station, the correction of elevation difference based on temperature lapse caused a large error. An empirical approach reflecting the effects of solar irradiance and advection was suggested in order to increase the reliability of the results. The normalized slope irradiance, which was determined by normalizing the solar irradiance difference between a horizontal surface and a sloping surface from 1100 to 1500 LST on a clear day, and the deviation relationship between the horizontal surface and the sloping surface at the 1500 LST temperature on each day were presented as simple empirical formulas. In order to simulate the phenomenon that causes immigrant air parcels to push out or mix with the existing air parcels in order to decrease the solar radiation effects, an advection correction factor was added to exponentially reduce the solar radiation effect with an increase in wind speed. In order to validate this technique, we estimated the 1500 LST air temperatures on 177 clear days in 2012 and 2013 at 10 sites with different slope aspects in a mountainous catchment and compared these values to the actual measured data. The results showed that this technique greatly improved the error bias and the overestimation of the solar radiation effect in comparison with the existing methods. By applying this technique to the Korea Meteorological Administration’s 5-km grid data, it was possible to determine the temperature distribution at a 30-m resolution over a mountainous rural area south of Jiri Mountain National Park, Korea.

Age of source rocks of the Late Precambrian metaterrigenous sediments of the South Ulutau mountains, Central Kazakhstan: U-Pb and Sm-Nd isotope data

Age of source rocks of the Late Precambrian metaterrigenous sediments of the South Ulutau mountains, Central Kazakhstan: U-Pb and Sm-Nd isotope data

Granodiorites of the South Mountain Batholith (Nova Scotia, Canada) derived by partial melting of Avalonia granulite rocks beneath the Meguma terrane: Implications for the heat source of the Late Devonian granites of the Northern Appalachians

The Late Devonian South Mountain Batholith (SMB) of Nova Scotia is the largest batholith of the northern Appalachians. The peraluminous granitic rocks range from biotite granodiorite to leucogranite. Samples collected from a drill core of the Scrag Lake granodioritic pluton of the western SMB are chemically homogeneous from the surface to a depth of ~1425m. The homogeneous composition implies that the granodiorite was derived from a relatively homogeneous source and that country rock assimilation was not an important source for the parental magma. Equilibrium partial melt modeling of underlying sub-Meguma granulite rocks indicates that they are the primary source rocks of the granodiorites. We suggest that mantle-derived magmas intruded the lower crust and induce large-scale melting of the granulite basement rocks to produce the granodiorites. Fractional crystallization of the granodiorites plus assimilation of Meguma Supergroup metasediments likely produces the silica-rich rocks of the SMB. The cause of mantle melting is uncertain however it may be related to the transitioning of the northern Appalachians from a position above the deep mantle Pacific large low shear velocity province (LLSVP) to a higher shear velocity region of the mantle.