956 resultados para Arid lands
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The objectives of this "Statewide Comprehensive Outdoor Recreation Plan" are to inventory existing recreation areas in Iowa, determine current demand, define and analyze problems, determine needs, delineate responsibilities, correlate planning, present an action plan and establish a priority system for the development of outdoor recreational facilities.
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Durante el siglo XIX se ejecutan en Catalunya proyectos de grandes regadíos en las tierras con mejores aptitudes para ello, como son las de la Depresión Central leridana, las del delta del Ebro o las del Bajo Llobregat. La excepción será la llanura del Ampurdán, concretamente, su mitad norte. No obstante, la profusión de intentos es elevada, aunque ninguno dará resultados prácticos hasta los años 60 del siglo XX. Esto ha reforzado su desconocimiento y, mediante el artículo, se quiere paliar este déficit. En primer lugar, se repasan algunos de los viajeros y eruditos que, entre los siglos XVII y XIX, facilitaron datos sobre los riegos existentes y algunas propuestas para mejorarlos. A continuación se analizarán los tres intentos más significativos para ampliarlos durante la segunda mitad del XIX. Se abordarán sus objetivos, sus peculiaridades, sus promotores, los discursos que los justificaron y los motivos de su fracaso
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A high resolution mineralogical study (bulk-rock and clay-fraction) was carried out upon the hemipelagic strata of the Angles section (Vocontian Basin, SE France) in which the Valanginian positive C-isotope excursion occurs. To investigate sea-level fluctuations and climate change respectively, a Detrital Index (DI: (phyllosilicates and quartz)/calcite) and a Weathering Index (WI: kaolinite/(illite + chlorite)) were established and compared to second-order sea-level fluctuations. In addition, the mineralogical data were compared with the High Nutrient Index (HNI, based on calcareous nannofossil taxa) data obtained by Duchamp-Alphonse et al. (2007), in order to assess the link between the hydrolysis conditions recorded on the surrounding continents and the trophic conditions inferred for the Vocontian Basin. It appears that the mineralogical distribution along the northwestern Tethyan margin is mainly influenced by sea-level changes during the Early Valanginian (Pertransiens to Stephanophorus ammonite Zones) and by climate variations from the late Early Valanginian to the base of the Hauterivian (top of the Stephanophorus to the Radiatus ammonite Zones). The sea-level fall observed in the Pertransiens ammonite Zone (Early Valanginian) is well expressed by an increase in detrital inputs (an increase in the DI) associated with a more proximal source and a shallower marine environment, whereas the sea-level rise recorded in the Stephanophorus ammonite Zone corresponds to a decrease in detrital influx (a decrease in the DI) as the source becomes more distal and the environment deeper. Interpretation of both DI and WI, indicates that the positive C-isotope excursion (top of the Stephanophorus to the Verrucosum ammonite Zones) is associated with an increase of detrital inputs under a stable, warm and humid climate, probably related to greenhouse conditions, the strongest hydrolysis conditions being reached at the maximum of the positive C-isotope excursion. From the Verrucosum ammonite Zone to the base of the Hauterivian (Radiatus ammonite Zone) climatic conditions evolved from weak hydrolysis conditions and, most likely, a cooler climate (resulting in a decrease in detrital inputs) to a seasonal climate in which more humid seasons alternated with more arid ones. The comparison of the WI to the HNI shows that the nutrification recorded al: the Angles section from the top of the Stephanophorus to the Radiatus ammonite Zones (including the positive C-isotope shift), is associated with climatic changes in the source areas. At that time, increased nutrient inputs were generally triggered by increased weathering processes in the source areas due to acceleration in the hydrological cycle under greenhouse conditions This scenario accords with the widely questioned palaeoenvironmental model proposed by Lini et al., (1992) and suggests that increasing greenhouse conditions are the main factor that drove the palaeoenvironmental changes observed in the hemipelagic realm of the Vocontian Basin, during the Valanginian positive C-isotope shift. This high-resolution mineralogical study highlights short-term climatic changes during the Valanginian, probably associated to rapid changes in the C-cycle. Coeval Massive Parana-Etendeka flood basalt eruptions may explain such rapid perturbations. (C) 2011 Elsevier B.V. All rights reserved.
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New stratigraphic data along a profile from the Helvetic Gotthard massif to the remnants of the North Penninic basin in eastern Ticino and Graubunden are presented. The stratigraphic record together with existing geochemical and structural data, motivate a new interpretation of the fossil European distal margin. We introduce a new group of Triassic facies, the North-Penninic-Triassic (NPT), which is characterised by the Ladinian ``dolomie bicolori''. The NPT was located in-between the Brianconnais carbonate platform and the Helvetic lands. The observed horizontal transition, coupled with the stratigraphic superposition of a Helvetic Liassic on a Briaconnais Triassic in the Luzzone-Terri nappe, links, prior to Jurassic rifting, the Brianconnais paleogeographic domain at the Helvetic margin, south of the Gotthard. Our observations suggest that the Jurassic rifting separated the Brianconnais domain from the Helvetic margin by complex and protracted extension. The syn-rift stratigraphic record in the Adula nappe and surroundings suggests the presence of a diffuse rising area with only moderately subsiding basins above a thinned continental and proto-oceanic crust. Strong subsidence occurred in a second phase following protracted extension and the resulting delamination of the rising area. The stratigraphic coherency in the Adula's Mesozoic questions the idea of a lithospheric m lange in the eclogitic Adula nappe, which is more likely to be a coherent alpine tectonic unit. The structural and stratigraphic observations in the Piz Terri-Lunschania zone suggest the activity of syn-rift detachments. During the alpine collision these faults are reactivated (and inverted) and played a major role in allowing the Adula subduction, the ``Penninic Thrust'' above it and in creating the structural complexity of the Central Alps. (C) 2012 Elsevier B.V. All rights reserved.
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Over the past two decades, soil ecotoxicologists have made strides in utilizing the basic concepts and advancements in soil zoology and ecology. They have applied the existing tools, and developed new ones to investigate how chemical contamination can affect soil ecosystems, including the degradation or destruction of soil quality and habitats or the diminishment of belowground biodiversity. Soil ecotoxicologists are applying a suite of standard protocols, originally developed as laboratory tests with single chemicals (e.g., pesticides), and further enhancing both the approaches and protocols for the assessment of contaminated lands. However, ecological relevance of some approaches remains unresolved. The authors discuss the main challenges for a coherent ecotoxicological assessment of soil ecosystems amid contaminated lands, and provide recommendations on how to integrate the effects of physical and chemical soil properties, the variations in the diversity of soil invertebrates, and the interactions among organisms of various trophic levels. The review examines new international approaches and test methods using examples from three continents (in particular research conducted in Brazil), and provides recommendations for improving ecological relevance of ecotoxicological investigations of contaminated lands.
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The objective of this work was to evaluate the species composition and functional groups of ants in nonagricultural (NA) and in irrigated areas (S, seasonal irrigation; P, irrigation with well water; W, irrigation with wastewater) in an arid agricultural region in central Mexico, throughout 2005 and 2006. A total of 52,358 ants belonging to 6 subfamilies, 21 genera and 39 species was collected using pitfall traps. The species best represented in all plots were: Forelius pruinosus, Pheidole obtusospinosa, Monomorium minimum and Dorymyrmex spp. NA plots recorded the highest density of ants. The highest values for diversity (H') and equitativity (J') were recorded in NA and P plots, while the lowest were recorded in W plots. Cluster analysis showed two different groups regarding species composition: NA-S and W-P. Functional groups recorded were: dominant Dolichoderinae, three species; subordinate Camponotini, five species; hot climate specialists, three species; tropical climate specialists, seven species; cold climate specialists, five species; cryptic species, one species; opportunists, six species; generalized Myrmicinae, nine species. Agricultural activity affects the structure of the ant community with epiedaphic forage, and the constant use of irrigation wastewater in conjunction with intense agricultural practices has negative effect upon species richness of epiedaphic ants.
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Miller Creek is on the 2006 Section 303d Impaired Waters List and has a 19,926 acre watershed. All indicators, as reported in the Miller Creek assessment, show that the impairment is due to sediment and nutrient delivery from upland runoff which contributes to elevated water temperatures, excessive algae, and low dissolved oxygen levels within the stream. In an effort to control these problems, the Miller Creek Water Quality Project will target areas of 5 tons per acre or greater soil loss or with 0.5 tons per acre or greater sediment delivery rates. The assessment revealed these targeted priority lands make up 32% or 6,395 acres of the Miller Creek watershed. Priority lands include cropland, pasture land, timber, and sensitive riparian areas. It is the goal of this project to reduce sediment delivery by 70% on 60% or 3,837 acres of these priority lands. This will be accomplished through installation of strategically placed structural practices, rotational grazing systems, and buffer strips. These practices will reduce soil loss, reduce sediment delivery, improve water quality, and improve wildlife habitat in the watershed. Utilizing partnerships with NRCS and IDALS-DSC will be important in making this project successful. In addition to using matching funds from EQIP, WHIP, and CRP, the Monroe SWCD is committed to prioritizing local cost share funds through IFIP and REAP for use in the Miller Creek Watershed.
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The Central Park Lake Watershed Assessment and Management Plan identified four categories where improvements are needed to remove the 23 acre lake from the impaired waters list. These include the wastewater system, runoff from surrounding lands, in-lake nutrient re-suspension and runoff from hard surfaces within the park. The lake is currently impaired for bacteria, algae and pH. Through outcomes of the Watershed Assessment and Management Plan, this proposal includes for abandonment and reclamation of the single cell wastewater lagoon site, replacement with three conventional septic systems and construction of two wetlands. One of the wetlands is located on the same site as the reclaimed lagoon and the other is located to intercept sediment and trap nutrients transported by tile lines. The prescribed wastewater system improvements are based on assessment by grab samples test by the State Hygienic Lab, development of a Preliminary Engineering Report, soil analysis and communication with IDNR wastewater officials. The two wetland sites were assessed by officials from IDALS and the Jones County SWCD. This project is part of $1.7 million lake restoration effort to reclaim the 47 year old lake. The lake has a positive economic impact of more than $7.6 million annually and supports an average annual visitation of 58,145, according to the Iowa Lakes Valuation Project, conducted by Iowa State University.
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The Muchakinock Creek Watershed Project began in February of 2005 to treat upland soil erosion in the creek that has lead to a 303(d) impairment. The Mahaska SWCD is currently administering this cost-share program to promote terraces, basins and grade stabilization structures. The District is now seeking funding from WIRB to treat specific abandoned mine lands in the Muchakinock Creek Watershed. These areas contribute sediment to the creek at levels second only to agricultural lands as well as acid mine drainage from open pits mines that have been left to decay across the county. The WIRB funding would be used to compliment Federal Abandoned Mine Land (AML) funding in the reclamation of these areas.
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This document includes the history, photos and maps of Iowa's state parks including forest & scientific preserves and scenic & historic parks.
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The object of this research project is to construct and evaluate several bituminous concrete base overlays with various high penetration bituminous products which have the potential to reduce future maintenance and construction costs. In September of 1981 nine different bituminous test sections were constructed on Osceola County roads A-34 and A-46 east of Ashton. Asphalt binders used were AC-5 asphalt cement, SC-800 liquid asphalt, MC-3000 cutback asphalt, CSS-1 emulsion and HFMS-2 emulsion. Aggregate for four of the test sections consisted of salvaged bituminous pavement and new aggregate combined. Each section was road mixed using a different binder arid placed 2-1/4" thick with a motor patrol. The other five test sections consisted of an AC-5 Type B asphalt concrete control section and four plant-mixed, cold-laid bituminous concrete overlay sections using new aggregate. The material was mixed in a continuous drum mix plant and laid with a full width paver.
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The objective of this work was to obtain prevalence estimates of cloudy vaginal mucus in artificially inseminated Holstein cows raised under intense heat, in order to assess the effect of meteorological conditions on its occurrence during estrus and to determine its effect on conception rate. In a first study, an association was established between the occurrence of cloudy vaginal mucus during estrus and the conception rate of inseminated cows (18,620 services), raised under intense heat (mean annual temperature of 22°C), at highly technified farms, in the arid region of northern Mexico. In a second study, data from these large dairy operations were used to assess the effect of meteorological conditions throughout the year on the occurrence of cloudy vaginal mucus during artificial insemination (76,899 estruses). The overall rate of estruses with cloudy vaginal mucus was 21.4% (16,470/76,899; 95% confidence interval = 21.1-21.7%). The conception rate of cows with clean vaginal mucus was higher than that of cows with abnormal mucus (30.6 vs. 22%). Prevalence of estruses with cloudy vaginal mucus was strongly dependent on high ambient temperature and markedly higher in May and June. Acceptable conception rates in high milk-yielding Holstein cows can only be obtained with cows showing clear and translucid mucus at artificial insemination.
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The Valanginian is marked by a major platform demise inducing a hiatus in the northern Tethyan neritic carbonate record from the top of the lower Valanginian to the lower Hauterivian. New biostratigraphic and chemostratigraphic data from the Ollioules section (Provence Platform, southern France) are presented here, demonstrating that a large part of the upper Valanginian is preserved in an inner platform environment. The thick, upper Valanginian, aggrading carbonate succession is observed in an aborted rift domain, implying relatively low subsidence. In this context, a relatively long-term sea-level rise was required to sustain a keep-up style of carbonate production. Like the Apulian Platform, the remarkable preservation of the Provence Platform may have been favored by its remoteness from terrigenous source areas, as suggested by the low clastic inputs and low P-accumulation rates. Two main biotic community replacements are observed in Ollioules. The first saw the development of abundant microbialites and algae at the onset of the late Valanginian. A Tubiphytes concentration occurred during the coolest climatic conditions and the transition towards arid conditions, whereas the subsequent Lithocodium-Bacinella and orbitolinids assemblages developed under low nutrient conditions during a warmer interval. Both assemblages may have been triggered by increased alkalinity. The second community replacement saw the installation of coral- and rudist-dominated communities during the latest Valanginian to early Hauterivian. They indicate a change to oligotrophic, open marine conditions. Six medium-scale sequences have been defined in Ollioules, indicating short-term transgressive-regressive trends superimposed on a long-term transgression. Low nutrient inputs and relatively low subsidence in an aggradational context may explain the survival of the isolated Provence Carbonate Platform during a time of widespread drowning episodes and platform demise in the northern Tethyan domain. (c) 2012 Elsevier B.V. All rights reserved.
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In order to establish guidelines for irrigation water management of banana cv. Pacovan (AAB group, Prata sub-group) in Petrolina County, northeastern Brazil, the root distribution and activity were measured on an irrigated plantation, in a medium texture soil, with plants spaced in a 3 x 3 m grid. Root distribution was evaluated by the soil profile method aided by digital image analysis, while root activity was indirectly determined by the changing of soil water content and by the direction of soil water flux. Data were collected since planting in January 1999 to the 3rd harvest in September 2001. Effective rooting depth increased from 0.4 m at 91 days after planting (dap), to 0.6 m at 370, 510, and 903 dap, while water absorption by roots was predominantly in the top 0,6 m.
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The water consumption and the crop coefficient of the banana cv. Pacovan were estimated in Petrolina County, northeastern Brazil, in order to establish guidelines to irrigation water management. Evaluations were carried out since planting in January 1999 to the 3rd harvest in September 2001 on a microsprinkler irrigated orchard, with plants spaced in a 3 x 3 m grid. Average daily water consumption was 3.9, 4.0, and 3.3 mm in the 1st, 2nd and 3rd growing seasons, respectively. Crop coefficient values increased from 0.7 (vegetative growth) to 1.1 (flowering). Even with high soil water availability, transpiration was reduced due to high evaporative demand.