Made available in DSpace on 2014-06-11T19:27:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-10-17Bitstream added on 2014-06-13T20:36:27Z : No. of bitstreams: 1 aquino_a_me_rcla.pdf: 2664343 bytes, checksum: 2664dac2efd41911b0423e12757905d3 (MD5) / Trata-se do estudo macro, micromorfológico, mineralógico, físico e químico da cobertura de solos de uma área experimental para fins de irrigação com efluente de esgoto tratado. A área localiza-se na cidade de Piracicaba, na Fazenda Taquaral, arrendada à Usina Cosan, para cultivo da cana-de-açúcar. A área cedida pela Usina, unidade Santa Helena, para o experimento foi dividida em 10 parcelas e, tanto essas, quanto o efluente, receberão um determinado tipo de tratamento. Os objetivos deste trabalho foram compreender o funcionamento atual dos solos da área experimental e verificar a possibilidade de influência e/ou modificações da cobertura de solos com a utilização do efluente. A metodologia adaptada para a pesquisa foi a Análise Estrutural da Cobertura Pedológica (BOULET, 1982 a, b). A caracterização dos solos foi feita em uma seqüência de solos e por meio de doze sondagens em cada parcela, de 0 a 100 cm de profundidade. As análises realizadas foram morfológica, física, química e mineralógica, tanto para a seqüência quanto para as sondagens. A análise micromorfológica foi realizada apenas para os solos da seqüência. As características do efluente foram cedidas pelo Departamento de Água e Esgoto de Piracicaba. As análises permitiram classificar o solo da área como Argissolo Vermelho-Amarelo Eutrófico típico, caracterizar e entender o funcionamento atual dos solos, antes da irrigação com o efluente e deduzir as possíveis mudanças do sistema solo a partir do início da irrigação. / The present work is a macro, micromorphological, mineralogical, physical and chemical study in an experimental area with the purpose of irrigation with treated sewage effluent. The area is located in the city of Piracicaba, at Taquaral Farm and leased to Cosan factory for sugar cane cultivation. The area was ceded by the factory for the experiment and divided in 10 parts, in accordance with the kind of treatment to be used with the effluent. This work had the purpose to analyze the soils of the experimental area, to understand its dynamics and to check the possibility of influence and change on the soils’ covering by the usage of effluents. The soil study was based on the methodology of the Structural Analysis of the Pedological Cover (BOULET, et al. 1982. a, b), with adapt. The soil characterization was made in a sequence of soil and through twelve investigations in each part, until 100cm depth. The analysis made were morphological, physical, chemical and mineralogical, for the sequence as well as for the investigations. The micromorphological analysis was made only in the sequence of soil. The effluent characteristics were provided by the Piracicaba Water and Sewage Department. The soil was classified into Typic Hapludults and the analyses were important to characterize and understand the soil’ dynamic before irrigation with treated sewage effluent and deduce the changes in the soil system with the effluent irrigation.

Revegetation is a reclamation method used to stabilize land that has been disturbed (i.e. Uranium contamination) by mining in an effort to establish a sustainable plant community. During 1986-88, large amounts of topsoil were removed at the site adjacent to the Tuba City disposal cell to remove windblown contaminated soil and construct the Uranium disposal cell. Re-establishing a sustainable plant community is critical to minimizing dust emissions, controlling erosion, and improving rangeland condition, and enhancing evapotranspiration. The objective of this study was to evaluate the long-term effectiveness of revegetation efforts by 1) comparing plant species composition and abundance on the reclaimed area and native rangeland protected from grazing, 2) current rangeland condition by comparing plant communities on grazed and protected native rangeland 3) differences in soil fertility, particle size distribution, and morphology that could be influencing vegetation differences in the three areas, 4) landscape-scale evapotranspiration rates and effects on groundwater recharge in the three plant communities, and 5) the value of using relatively undisturbed Legacy Management parcels as reference areas. Plant cover in the revegetated area was greater in 2014 (24%) than in 1998 (15%); however, plant species composition and diversity in the revegetated area and in the reference area remained markedly different. The effectiveness of revegetation is improving, but given the extended amount of time the improvement is not matching the protected area’s percent cover. The reference area showed highest cover during the early cool-season. However, the grazed area possessed the highest plant species composition and highest foliar cover in the late warm-season. The vegetation relevé estimate and foliar cover statistics show the revegetated area (24%) was significantly less than the surrounding vegetation (35%), even after 26 years since original revegetation. These results are critical in assisting Legacy Management to identify environmentally sustainable methods for the continuous management of this site and others in the area.

Cover crops not only improve soil conditions, but can also suppress weed growth. In a field experiment the influence of two cover crops, Secale cereale (stooling rye), and Lolium multiflorum (annual ryegrass), on the growth of Zea mays (maize) and C. esculentus (yellow nutsedge) was compared to the latter crop and weed’s growth at three control treatments which involved weed residues left on the soil surface, application of herbicides and weed control by hoeing. Maize emergence and growth were delayed in the presence of residues of both cover crop species, especially in annual ryegrass residues. C. esculentus growth was significantly inhibited in the area between the maize planting rows by the cover crops for the first 14 days after maize emergence, but this growth suppressing effect diminished after 28 days. In a controlled environment study, the influence of the same cover crops, together with Avena sativa (oats) and three cultivars of annual ryegrass were evaluated. Maize and C. esculentus growth were suppressed, especially by the root residues of the cover crops with the annual ryegrass cultivar ‘Midmar’ being the most suppressive. Chemical analysis of the leachate of root residues indicated the presence of phenolic acids and benzoxazolin-2(3 H)-one (BOA). It is suggested that weed growth could be reduced by the allelochemicals leached from cover crop residues but in order to achieve prolonged, effective weed control the combination of mulch retained on the soil surface and the application of herbicides will required. In an integrated weed management approach a possible reduction in the type and number of herbicide applications required for effective weed control, could be implemented. / Thesis (PhD)--University of Pretoria, 2012. / Plant Production and Soil Science / unrestricted

As landscapes become increasingly urbanized, there is an associated increase in impervious cover. Impervious surfaces, such as roads, rooftops, and parking lots contribute to the physical, hydrological, chemical, and biological alteration of stream systems. Biotic assemblages consistently degrade with increased watershed impervious cover; however, at low levels of impervious cover, these assemblages exhibit wide variability in biotic integrity. This study investigated which reach- and watershed-scale factors explained biotic condition (i.e., richness, flow traits, thermal traits, and tolerance for macroinvertebrates and fishes) at similar levels of low imperviousness. The primary objective was to identify factors that confer resistance for biota, such that they retain high biotic integrity at low levels of impervious cover, and, conversely, to determine which factors make biota more vulnerable to urban disturbance, such that they have low biotic integrity despite low levels of impervious cover. Forty sites were selected across Massachusetts within two narrow bands of impervious cover: 1–4% (n = 20) and 7–10% (n = 20). Models with reach-scale variables (reflecting habitat heterogeneity, flow, temperature, or water quality) or watershed-scale variables (representing natural characteristics, land use, flow alterations, and other measures of urbanization or impervious) explained additional variance compared to models with impervious cover alone. Reach-scale factors tended to explain more variance than watershed-scale factors for all biotic responses except fluvial fishes, with overall more variance explained for fish than macroinvertebrate assemblages. At the reach scale, colder water temperatures, higher dissolved oxygen, and more large wood were related to higher proportions of fluvial, coldwater, and intolerant fishes. For macroinvertebrates, warmer water temperature, smaller sediment size, and higher nitrate were related to higher macroinvertebrate richness and tolerance. At the watershed scale, air temperature emerged as an important predictor for both taxonomic groups and across response metrics; air temperature was highly correlated with high-elevation watersheds. Other important watershed-scale predictors were open water and dams, flow alteration, and other urban measures such as housing density, impervious in a 120-m buffer, and road crossings. Restoration should focus on strategies to reduce impacts that would degrade in-stream conditions that allow for higher biotic integrity, such as habitat heterogeneity, more large wood, and colder water temperatures. Similarly, watersheds should be prioritized for protection with those characteristics potentially more resistant to urban disturbance, such as high-elevation regions that retained high biotic integrity despite higher dam density, more road crossings, and more flow alteration.

archives@tulane.edu / 1 / Joseph Skelton

Limited photosynthetically active radiation (PAR) can reduce interseeded cover crop growth in corn (Zea mays L.). Two experiments in North Dakota evaluated the effect that hybrid relative maturity (RM), row width, and cover crop planting date have on cereal rye (Secale cereale L.) and winter camelina [Camelina sativa (L.) Crantz.] establishment when interseeded into 80 and 89 RM hybrids at V7 and R4 growth stages in 56- and 76 cm corn row widths. Cover crop biomass was typically less than 100 kg ha-1. In the following spring larger amounts of PAR beneath the 80 RM hybrid increased cover crop biomass by 20.8 kg ha-1. Cover crop biomass tended to be greater in the 76 cm row width but was not significantly different from the 56 cm width. Cover crops decreased residual soil nitrate by 6.0 kg ha-1 in the fall and by 15.6 kg ha-1 in the spring.

In the Midwest, it can be beneficial to interseed cover crops into corn (Zea mays L.) since there is a limited time for them to establish and grow after corn harvest. Research conducted in four environments in North Dakota quantified the impacts of planting method and time of planting when grown with or without corn competition on the establishment, and development of three cover crop species. Limited light intensity (less than 20%) under the corn canopy drastically reduced cover crop development. Soil water can also constrain cover crop establishment. Model simulations suggest soil water is more limiting for cover crop establishment in August compared with June or July. Interseeded cover crops had no effect on corn yield or the following soybean (Glycine max (L.) Merr.] crop due to minimal amounts of biomass produced.

Faba bean (Vicia faba Roth) is grown worldwide as a protein source for food, used for animal feed, and is a common cover crop in Europe, but is underutilized in Midwest farming systems. Faba bean, field pea (Pisum sativum L.), and forage pea were evaluated for biomass and chemical composition when sown after wheat. Faba bean, forage pea, balansa clover (Trifolium michelanium Savi), red clover (T. pratense L.), and rye (Secale cereale L.) were evaluated similarly when intersown into maize. Cover crops after wheat had no significant biomass differences, averaging 1210 kg ha-1, enough to support 1.5 animal unit month (AUM) ha-1 for a 450 kg cow with calf. Rye yielded the greatest (374 kg ha-1) of the intercrops with faba bean averaging similarly and other intercrops averaging significantly less. Intercrops did not affect maize yield. Faba bean has similar potential as other commonly used cover crops in the Midwest.

Att spela popmusik på orgel är en vanlig uppgift för kyrkomusiker i samband med t.ex. dop, vigsel, konfirmation och begravning. Behovet av att i en kyrkomusikalisk yrkessituation inom begränsade tidsramar skapa funktionella orgelarrangemang av musiken är utgångspunkten för denna studie, där processen att göra orgelcovers av fyra utvalda ABBA-låtar beskrivs och illustreras. Med enkelhet, originaltrohet och replikerbarhet som arbetets grundprinciper skapas låtarnas orgelversioner utifrån ABBA:s originalinspelningar och auktoriserade notutgåvor. Olika instrumentationer och arrangeringstekniker för att återge originalets helhetsklang och perceptuellt signifikanta element såsom beat, basgångar, stämsång, ”fills” och särskilda klangfärger prövas och motiveras utifrån förlagans egenskaper och orgelinstrumentets egenart. Som resultat eftersträvas klangrika, varierade och flexibla orgelversioner av låtarna i fråga som bygger på ett begränsat antal generella modeller för instrumentation och kan sparas och återskapas utifrån anteckningar om modellerna utan framställning av särskilda notexemplar. Arbetet ger prov på instrumentellt definierad arrangeringsprocess där originalverken är givna studioinspelningar och ”sound” utgör en viktig konstnärlig referens. / <p>Till dokumentationen hör inspelade orgelversioner av låtarna: 1. Waterloo,</p><p>2. Dancing Queen, 3. Take A Chance On Me och 4. The Winner Takes It All</p>

Bridge piers within moving water are exposed to an additional failure mechanism known as scour. Upon the scour depth reaching the foundation of the pier, the structural integrity of the pier, and consequently the bridge, can be jeopardized. Bridge pier scour is the result of a three-dimensional flow separation consisting primarily of the horseshoe vortex, flow acceleration along the sides of the pier, and wake vortices. There are numerous factors that can affect bridge pier scour, of which many of them have been studied extensively. However, there are still some factors where the knowledge base is limited: one example is the presence of an ice cover around bridge piers. In order to reduce the risk of failure induced by scour, regardless of the cause, a preferred option is to use scour countermeasures. However, an ideal countermeasure does not exist. Therefore, the purpose of this research is to design and test an improved bridge pier scour countermeasure, while also better understanding the effects an ice cover has on scour. Achieving a new countermeasure design consisted of a hybrid approach that combined both numerical and experimental modelling. The numerical model was used in an iterative manner to expedite the design process, as well as to reduce experimental costs. Upon testing and improving the initial collar design numerically, physical models were constructed for the purpose of testing experimentally. Experimental tests were performed at a 1:30 scale in the presence of a sand bed. The same experimental setup was used to investigate bridge pier scour under an ice cover, except a rigid structure was constructed to replicate an ice cover. The artificial ice cover possessed either a smooth or a rough underside and was installed in such a way to replicate a floating or fixed (pressurized) ice cover. The purpose of the new countermeasure design was to improve on the flat plate collar by guiding the horseshoe vortex in a novel manner. By doing so, the quantity of erosive forces contacting the bed was greatly reduced. In order to reach a final design, a series of prototype designs were tested, and are outlined in this thesis, as they provide valuable insight into the scour problem. The final countermeasure design resembles a contoured collar but is made of riprap, where it was found to reduce the scour depth and volume by 81.0% and 92.3%, respectively, while using 18% less riprap than the conventional flat riprap countermeasure. Upon investigating scour in the presence of an ice cover, it was found that the quantity of scour increases as the ice cover becomes rougher and as the flow becomes more pressurized beneath. Specifically, the scour depth under the rough ice cover and the most pressurized condition increased by 412%. It was demonstrated that implementing any device which increases the width of the pier has inherent limitations for reducing scour. Instead, having a depression around the pier, especially made of riprap, such that it is flush with the bed and can help guide the horseshoe vortex, was found to greatly reduce scouring. Furthermore, it was observed that the presence of any ice cover on the surface of the water generates greater pier scour, therefore necessitating that ice cover always be taken into consideration when designing bridges in cold climates.