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Soil conservation and the white agrarian environment in Colonial Zimbabwe, c. 1908-1980Maravanyika, Simeon January 2013 (has links)
This thesis utilizes three theoretical approaches; political ecology, settler culture and community conservation to examine soil conservation and the white agrarian environment in colonial Zimbabwe to evaluate to what extent players in government and the agricultural sector were conscious or concerned about preservation and conservation of the soil. The thesis also examines the role of local and international ideas in the colony’s conservationist tradition, and whether the soil conservation movement was identity-forming among the colony’s settler farmers. The history of conservation on settler farms in colonial Zimbabwe can be periodized into three broad timeframes - from the 1890s to around the mid-1930s, between 1934 and 1965 and the Unilateral Declaration of Independence (UDI) period. In the first three and half decades of the 20th century the history of conservation can best be described as being characterized by a series of “dilemmas.” The British South Africa Company (BSA Co.) administration did not pursue soil conservation in any significant, synchronized or sustained manner. In the second period, from 1934 to 1965, there was considerable progress in the construction of conservation works on settler farms. This process was the result of recommendations made by Natural Resources Commission, a body that was appointed in 1938 to investigate the status of the colony’s natural resources. The mid-1940s were characterized by the formation of Intensive Conservation Areas (ICAs) in settler farming districts whose mandate was to oversee the construction of conservation works to rehabilitate settler farms. With the support of the Natural Resources Board (NRB), and the Department of Conservation and Extension (CONEX), formed in 1948 to provide expertise on conservation-related matters and extension support, all settler farming areas were covered by trained CONEX staff, though in most instances very thinly distributed due to high demand for their service and manpower constraints in the department. The third period, the UDI era, was characterized by attempts by the minority settler government to forestall majority rule in the colony. Malawi and Zambia (formerly Nyasaland and Northern Rhodesia, respectively) had been granted their independence by Britain in 1964. As decolonization was taking place in other parts of Africa, black majority rule in colonial Zimbabwe also seemed imminent. To the alarm of the white minority government, Britain had set out to grant majority rule to its African colonies, including Southern Rhodesia (renamed Rhodesia after Zambia’s independence). The Ian Smith-led government of Rhodesia, feeling betrayed, declared UDI on 11 November 1965, delaying Zimbabwean independence by another 15 years. With the end of the Federation in 1963, the colony could no longer rely on federal resources as it had done between 1953 and 1963. Sanctions, imposed in reaction to UDI, further put the regime in a tight corner. Their impact was quite significant. Fuel had to be rationed, and general belt-tightening across the board inevitably followed as major Rhodesian exports such as tobacco and minerals were embargoed on international markets. The start of the liberation war at the end of the 1960s further complicated matters. / Thesis (DPhil)--University of Pretoria, 2013. / gm2014 / Historical and Heritage Studies / Unrestricted
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Protierozní opatření na orné půdě ve vnímání zemědělců / Farmers perception of anti-erosion practices on arable landTyslová, Radka January 2018 (has links)
(in english): Modern agriculture faces soil erosion as one of its problems in the Czech Republic. Soil conservation practices are implemented to prevent erosion. This thesis reports on perception of the soil conservation practices by farmers themselves. Hypothesis of the research is based on declaration of organic farming in the Czech Republic: to specifically protect natural sources. Main research question is: Is there a difference in perception of soil conservation practices between certified organic farmers and farmers using conventional methods? As a concept to examine perception, this thesis uses the theory of planned behavior developed by Icek Ajzen. Results show that farmers' attitudes towards soil conservation practices in general are negative. Their attitudes can be explained by intermingling beliefs about erosion, the agriculture subsidy system and own soil quality. Specific practices are evaluated by other than anti-erosion effects. The farmers do not perceive social pressure from their peers to adopt soil conservation practices and their perceived control over adoption of a practice is low. Evaluating the level of difficulty of specific practices, smaller farmers feel substantial difficulties regarding financial issues. The results do not indicate a difference in perception of soil...
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Exploring the Utility of High Resolution Imagery for Determining Wetland SignaturesDeLury, Judith Ann 03 July 2012 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Wetland habitats are characterized by periodic inundation and saturation by water creating anaerobic conditions that generate hydric soils and support hydrophytic vegetation. Wetland habitats provide important ecological functions including breeding grounds for fish, other wildlife, water purification, reduction in flooding, species diversity, recreation, food production, aesthetic value, and transformation of nutrients (Tiner, 1999). The multiple benefits of wetlands make them an important resource to monitor.
A literature review suggests a combination of geospatial variables and methods should be tested for appropriateness in wetland delineation within local settings. Advancements in geospatial data technology and ease of accessing new, higher resolution geospatial data make study at local levels easier and more feasible (Barrette et al, 2000).
The purpose of the current study is to evaluate new sources of geospatial data as potential variables to improve wetland identification and delineation. High resolution multispectral digital imagery, topographic data, and soils information are used to derive and evaluate independent variables. Regression analysis was used to analyze the data.
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The Effectiveness of the Conservation of Human Beings and of Soil by the CCC Camp in Denton, TexasVinson, Denny 06 1900 (has links)
The organization of the Emergency Conservation Work was found to possess many faults. The Seventy-Fifth Congress, taking cognizance of some of the more glaring imperfections, approved a measure reorganizing and re-establishing the Emergency Conservation Work under the name of The Civilian Conservation Corp. The bill eliminated many of the defects of the former organization, and invested authority and defined duties and regulations in such a manner that a more efficient institution resulted.
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Inlet-Adjacent Shoreline Behavior at Three Stabilized Inlets in Palm Beach County, FL (USA)Unknown Date (has links)
Shorelines are a primary source of attraction for the nearly two million tourists who visit Palm Beach County annually. Many of Palm Beach County beaches are located on barrier islands, separated by a series of inlets which serve as access points to the Intracoastal Waterway. However, inlets are often cited as a source of erosion, through interruption of littoral drift and interaction with nearshore hydrodynamics (e.g., causing wave diffraction or refraction). In an effort to mitigate potential negative impacts of the economically important tidal inlets, Palm Beach County has installed a sand transfer plant (STP) at two inlet locations, the Lake Worth Inlet and the South Lake Worth Inlet. Through analysis of annual aerial photography and beach profile surveys taken between 2000 and 2009, this study will determine what effect, if any, these sand transfer plants are having on the inlet-adjacent shorelines north and south of the two inlets with STP, as well as an inlet without an STP (Boca Inlet). This study hopes to increase the understanding of shoreline dynamics in Palm Beach County, which could recognize important alongshore patterns, such as the occurrence of erosional hot spots, to assist in future mitigation efforts. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection
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Avaliação da degradação do solo através da dinâmica da matéria orgânica, na micro bacia do Arroio Morungava, Gravataí, RSGomes, Márcia da Silva 15 September 2009 (has links)
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Previous issue date: 2009-09-15 / Nenhuma / A degradação dos solos é um dos principais problemas relacionados ao desenvolvimento sustentável, e um dos grandes desafios a serem enfrentados já neste século. A ação do homem no planejamento e desenvolvimento da ocupação do espaço na Terra requer cada vez mais uma visão ampla sobre as necessidades da população, os recursos terrestres e aquáticos disponíveis e o conhecimento sobre o comportamento dos processos naturais, para racionalmente compatibilizar necessidades crescentes com recursos limitados. A crescente degradação do solo sob exploração agrícola em todo o mundo despertou nos últimos anos uma preocupação com a qualidade do solo e a sustentabilidade da produção agrícola. A matéria orgânica do solo é um fator relevante na qualidade deste, sendo uma fonte de energia, de carbono e doadora de elétrons da grande maioria dos organismos, o que evidencia sua importância para a biota desempenhar suas funções no sentido de promover as propriedades do solo. O objetivo deste trabalho é avaliar a degradação do solo na microbacia do arroio Morungava, com uso da Equação Universal de Perda de Solo (EUPS), através de análise da variação temporal da matéria orgânica nos horizontes superficiais, em solos Hidromórficos e Argissolos, sob práticas de cultivo em diferentes períodos de uso (18 meses de cultivo; 10 anos de cultivo; 15 anos de cultivo e mais de 30 anos de cultivo), utilizando áreas de mata nativa como referência. Em condições naturais os argissolos mostram um aumento de matéria orgânica (MO) com a profundidade. Nos horizontes superficiais dos solos cultivados analisados observa-se perda de MO por erosão e oxidação superficial, com pouca translocação vertical. Neste caso, a erosão superficial acelerada antropicamente, faz com que o Horizonte B dos argissolos fique próximo a superfície, eventualmente exposto, com o passar do tempo. Já os solos hidromórficos verificam-se grandes perdas iniciais com a retirada de matas nativas, o que pode ser em parte atribuído à oxidação acelerada da MO, devido às mudanças ambientais. Para os solos hidromórficos com mais de 15 anos de uso, verifica-se um comportamento inverso, ocorrendo um significativo aumento superficial da MO, o que pode ser devido ao aporte de MO originado dos argissolos adjacentes. Assim, as planícies aluvionares, para tempos de uso superiores há 15 anos, devem provavelmente atuar como zonas de acumulação de MO na bacia hidrográfica. Há um provável processo menos intenso de translocação vertical, o qual é observado nos primeiros 10 anos de uso dos hidromórficos. Quanto à avaliação espacial de perda de MO observa-se taxas com variação de 0 até 239,15 t ha¯¹ ano¯¹ com o uso do solo atual. Assim, 54,12 % da área apresentam taxas de perda de MO entre 0 a 0,5 t ha¯¹ ano¯¹ 42,21 % variam de 0,5 a 5 t ha¯¹ ano¯¹e os demais 3,67 % de área apresentam perdas de MO acima de 5 t ha¯¹ ano¯¹. Em um cenário onde a legislação ambiental (Código Florestal Federal - Lei 4.771 de 1965 e Código Florestal Estadual - Lei 9.519 de 1992) é cumprida, com reflorestamento nas Áreas de Preservação Permanente ? APPs, referente às encostas com declividade acima de 45º e faixas de 30 metros de cada lado, ao longo dos cursos d´água, observa-se 62,17 % da área com taxas de perda de MO entre 0 a 0,5 t ha¯¹ ano¯¹, 36,86 % variam de 0,5 a 5 t ha¯¹ ano¯¹e os demais 0,97 % de área apresentam perdas de MO acima de 5 t ha¯¹ ano¯¹, chegando a atingir 37,28 t ha¯¹ ano¯¹em alguns pontos. Para um cenário onde a faixa de preservação é de apenas 5 metros de cada lado, ao longo dos cursos d´águas, de acordo com a legislação ambiental do Estado de Santa Catarina (Art. 114 da Lei Estadual 14.675, de 13 abril de 2009), observa-se que as taxas de perda de MO aumentam. No cenário anterior as perdas acima de 5 t ha¯¹ ano¯¹, atingem apenas 0,97% do total da área. Aplicando a legislação do Estado de Santa Catarina, as taxas de perda acima de 5 t ha¯¹ ano¯¹, atingem 1,03 % do total da área. As taxas baixas de perda de MO (abaixo de 0,5 t ha¯¹ ano¯¹) para o cenário de 30 metros de preservação chegam a 62,17% da área. Já no cenário com faixa de preservação de apenas 5 metros, as taxas baixas de perda de MO chegam a 53,16% da área. Apesar de ser uma diferença pequena de taxas de perda de MO, estas taxas apresentadas comprovam que a diminuição das faixas de preservação de 30 metros para cinco metros, acarretará em prejuízos ao meio ambiente. Em um cenário onde toda a faixa de preservação de 30 metros de cada lado, ao longo dos cursos d´água, é retirada, as taxas de perda de MO variam de 0 até 239,15 t ha¯¹ ano¯¹. Neste caso 53,16 % da área apresenta taxas de perda de MO entre 0 a 0,5 t ha¯¹ ano¯¹, 43,02 % variam de 0,5 a 5 t ha¯¹ ano¯¹ e 3,82 % de área apresentam perdas de MO acima de 5 t ha¯¹ ano¯¹, chegando a atingir 239,15 t ha¯¹ ano¯¹ em alguns pontos. Essas taxas de perda são equivalentes ao uso do solo atual da área. Isto ocorre pelo fato da microbacia do arroio Morungava apresentar grandes extensões de faixa de preservação ao longo desses cursos d´água, totalmente desmatadas. O cenário criado para desmatamento de 30 metros é semelhante à situação real da área. A partir dos resultados obtidos das coletas de campo e dados gerados em laboratório, conclui-se que a micro bacia do arroio Morungava está sofrendo processo erosivo acelerado com o decorrer dos anos, principalmente em zonas de maior declividade, onde predominam os argissolos. Já os solos em posição fisiográficas com baixa erosão potencial superficial, como os hidromórficos, atuam como zonas de acumulação de sedimentos e matéria orgânica. Verifica-se uma variação ampla nas taxas de perda de MO com o uso do solo atual, com teores elevados nas áreas com maior declividade. Estes teores, de acordo com cenários gerados de reflorestamento, podem diminuir com o cumprimento da legislação ambiental. Assim pode-se afirmar que a EUPS foi fundamental para avaliar a perda de matéria orgânica na microbacia. / Soil degradation is one of the main concerns regarding sustainable development, and one of the challenges to be faced on this century. Mankind actions on planning and development of Earth occupation, needs more and more a broader view of population needs, available terrestrial and hydric resources and knowledge over natural processes behavior, to rationally conciliate growing needs with limited resources. The worldwide growing soil degradation due to agricultural exploitation, over the last years awoke a concern with soil quality and agricultural production sustainability. The soil organic matter is a relevant factor for its quality, being energy and Carbone source and an electron donator to most organisms, which only shows how it is important to biota?s functions and promote soil proprieties. The objective of this study is to evaluate the soil degradation at the micro basin of the Morungava stream, using the Universal Soil Loss Equation (USLE), through temporal variation analysis of organic matter on superficial horizons, on hydromorphic and argillaceous soils, under cultivation on different usage periods (18 months of cultivation, 10 years of cultivation, 15 years of cultivation and more than 30 years of cultivation), utilizing areas of native forest as reference. In natural conditions argillaceous soils show an increase in organic matter (OM) as it deepens. On the analyzed cultivated soils superficial horizons, was observed a loss of OM due to erosion and superficial oxidation, with low vertical translocation. In this case, the superficial erosion hasten by anthropic influence, causes the B horizon of argillaceous soils to be near the surface, eventually exposed with time. On the hydromorphic soils, there are big initial losses with the removal of native forests, which can be in part caused by hasten oxidation of OM due to environmental changes. To hydromorphic soils with more than 15 years of usage, a inverse behavior is observed, occurring a significant increase of superficial OM, which can be due to the arrive of OM from the adjacent argillaceous soils. So, the alluvial plains, to usage periods greater than 15 years, probably act as OM accumulation zones on the basin. There is a probable process less intense of vertical translocation, which is observed during the first 10 years of hydromorphic soil usage. As for the spatial evaluation of OM loss, its observed with variation from 0 to 239,15 t.ha¯¹.year¯¹ with current soil usage. This way, 54,12% of the area presents OM loss rate between 0 and 0,5 t.ha¯¹.year¯¹, 42,21% varies from 0,5 to 5 t.ha¯¹.year¯¹, and the remaining 3,67% of the area show OM losses superior to 5 t.ha¯¹.year¯¹. In a scenery where the environmental legislation (Federal Forest Code ? Law 4.771 of 1965 and State Forest Code ? Law 9.519 of 1992) is followed, with reforesting of Permanent Preservation Areas (APPs), referring to acclivity superior to 45° and a 30 meters preservation band from the margins of any watercourse, is observed that 62,17% of the area have a OM loss rate between 0 and 0,5 t.ha¯¹.year¯¹, 36,86% varies from 0,5 to 5 t.ha¯¹.year¯¹ and the remaining 0,97% have a OM loss rate superior to 5 t.ha¯¹.year¯¹, peaking 37,28 t.ha¯¹.year¯¹ at some points. In a scenery where the preservation band is only 5 meters from the margin of watercourses, in accordance with the environmental legislation of Santa Catarina state (Art.114 State Law 14.675 from 2009, April 13), its observed an increase in the OM loss Rates. If in the previous scenery the OM losses over 5 t.ha¯¹.ano¯¹, were only 0,97% of total area, applying the Santa Catarina State Law, the OM losses over 5 t.ha¯¹.ano¯¹, are 1,03% of total area. The low OM loss rates (under 0,5 t.ha¯¹.ano¯¹,) on the 30 meters preservation scenery were 62,17% of the area, applying the Santa Catarina state 5 meters preservation scenery it drops to 53,16% of the area. Even if it is a small difference on OM loss rates, these rates testify that the reduction of the preservation bands will incur in harm to the environment. In a scenery where all the preservation band is removed along the watercourses, the OM loss rates varies from 0 to 239,15 t.ha¯¹.year¯¹. In which case 53,16% of the area presents OM loss rates from 0 to 0,5 t.ha¯¹.year¯¹, 43,02% varies from 0,5 to 5 t.ha¯¹.year¯¹ and 3,82% of the area show OM losses over 5 t.ha¯¹.year¯¹, peaking 239,15 t.ha¯¹.year¯¹ at some points. Those loss rates are equivalent to those of the current soil usage in this area. This is due to the fact that the micro basin of the Morungava stream presents great extensions of preservation bands along its watercourses totally depleted. The scenery created with no preservation band is similar to the current situation of the area. From the gotten results of the collections of field and data generated in laboratory, one concludes that the micro basin of the Morungava stream is suffering sped up erosive process with elapsing of the years, mainly in zones of bigger declivity, where the argissolos predominate. Already the ground in position fisiográficas with low superficial potential erosion, as the hidromórficos, act as zones of accumulation of sediments and organic matter. An ample variation in the taxes of loss ME with the use of the ground is verified current, with texts raised in the areas with bigger declivity. These texts, scenes in accordance with generated of reforestation, can diminish with the fulfilment of the ambient legislation. Thus it can be affirmed that the EUPS was basic to evaluate the loss of organic matter in the micron basin.
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Outback or at home? : environment, social change and pastoralism in Central AustraliaGill, Nicholas, Geography & Oceanography, Australian Defence Force Academy, UNSW January 2000 (has links)
This thesis examines the responses of non-indigenous pastoralists in Central Australian rangelands to two social movements that profoundly challenge their occupancy, use and management of land. Contemporary environmentalism and Aboriginal land rights have both challenged the status of pastoralists as valued primary producers and bearers of a worthy pioneer heritage. Instead, pastoralists have become associated with land degradation, biodiversity loss, and Aboriginal dispossession. Such pressure has intensified in the 1990s in the wake of the native Title debate, and various conservation campaigns in the arid and semi-arid rangelands. The pressure on pastoralists occur in the context of wider reassessment of the social and economic values or rangelands in which pastoralism is seen as having declined in value compared to ???post-production??? land uses. Reassessments of rangelands in turn are part of the global changes in the status of rural areas, and of the growing flexibility in the very meaning of ???rural???. Through ethnographic fieldwork among largely non-indigenous pastoralists in Central Australia, this thesis investigates the nature and foundations of pastoralists??? responses to these changes and critiques. Through memory, history, labour and experience of land, non-indigenous pastoralists construct a narrative of land, themselves and others in which the presence of pastoralism in Central Australia is naturalised, and Central Australia is narrated as an inherently pastoral landscape. Particular types of environmental knowledge and experience, based in actual environmental events and processes form the foundation for a discourse of pastoral property rights. Pastoralists accommodate environmental concerns, through advocating environmental stewardship. They do this in such a way that Central Australia is maintained as a singularly pastoral landscape, and one in which a European, or ???white???, frame of reference continues to dominate. In this way the domesticated pastoral landscapes of colonialism and nationalism are reproduced. The thesis also examines Aboriginal pastoralism as a distinctive form of pastoralism, which fulfils distinctly Aboriginal land use and cultural aspirations, and undermines the conventional meaning of ???pastoralism??? itself. The thesis ends by suggesting that improved dialogue over rangelands futures depends on greater understanding of the details and complexities of local relationships between groups of people, and between people and land.
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Use and Abuse of Southwestern Rivers: The Pueblo DwellerDiPeso, Charles C. 23 April 1971 (has links)
From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / In response to the 20th century crisis of environmental destruction by unrestricted technological exploitation, some archaeologists are studying alternative modes of resource development as practiced by earlier men. The pueblo Indians of the arid southwestern deserts were basically upland corn farmers, who, after A.D. 1000, found it necessary to exploit their environment because of varying combinations of climatic change and increased population pressures. In the northeastern part of the state of Chihuahua, urban engineers, ca 1050, harnessed the entire Casas Grandes dendritic pattern by installing a set of linked hydraulic appointments which included various upslope protective devices such as linear border, check dams and riverside and hillside terraces. Not only were they able to visualize an entire dendritic pattern as the target area, but also they were able to conceive of rainfall and topsoil as a single factor in their control designs. Although large amounts of human labor were needed to construct and maintain these systems, few raw materials were needed. When the mountain-born waters reached the lower valleys, they were clear and sluggish, did not flood the bottomlands, and because of the reduced speed, could easily be diverted into canals and reservoirs, supplying the cities with domestic water and the farmers with irrigation water. Many further studies are needed of these pre-Columbian systems.
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Sediment removal from urban runoff using seep berms and vegetative filtrationHamade, Firas Nadim 13 January 2014 (has links)
Previous field demonstration projects in metro-Atlanta have shown that seep berms, which are elongated sedimentation basins at the outlet of a disturbed land area, can provide high suspended sediment trap efficiencies with respect to coarse sediments on construction sites having drainage areas greater than five acres. Previous literature has shown that vegetative filter strips are efficient traps for fine suspended sediment in stormwater runoff. A combination of a seep berm and vegetative filter in series was studied in this thesis as an erosion control measure with quantification of its flow resistance and sediment removal efficiency. First, a field demonstration project was implemented to evaluate seep berms as a viable erosion control measure through a side-by-side comparison with the more commonly-used silt fences on construction sites with drainage areas less than five acres in metro Atlanta. High suspended sediment trap efficiencies were recorded for the seep berm on two separate sites, and the seep berm was shown to be superior to silt fences with respect to sediment control in the site runoff. Then a vegetative filter was studied in the laboratory in a specially-built flume for that purpose. The relationship between vegetative drag coefficient and various parameters reflecting flow conditions and vegetation density in steady, uniform open channel flow was studied in the flume. Both rigid, emergent vegetation and submerged, flexible vegetation were studied at two different plant densities. The application of porous media flow concepts to open channel flow through vegetation resulted in a collapse of data for vegetative drag coefficient for the various vegetation types and densities into a single relationship when plotted against vegetative stem Reynolds number. Point velocity and turbulence intensity profiles at different locations in the vegetative filter were recorded with an acoustic Doppler velocimeter to observe the turbulence structure of the flow and its effects on vegetative drag and settling of sediment. A sediment slurry consisting of a suspension of fine sand was fed into the flume, and an automated sampler was used to measure suspended sediment concentrations along the vegetative filter length for a series of discharges from which sediment flux and trap efficiency could be determined. Experimental data for trap efficiency were plotted against a dimensionless settling efficiency for each type of vegetation and density. These relationships, along with the one developed for the coefficient of drag, were applied in a numerical design technique that allows designers to determine the flow depth, velocity and trap efficiency of a vegetative filter of known dimensions for a given flow rate, sediment grain size distribution, slope, and vegetation density. In a typical design example, the combined trap efficiency proved that a seep berm followed by a vegetative filter can be a very effective erosion control measure.
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Experimentelle Untersuchung zum Einfluss der Makroporendichte auf das Infiltrationsverhalten landwirtschaftlich genutzter BödenBornkampf, Constance 28 January 2014 (has links) (PDF)
Soil is an important ecosystem and at the same time filter and storage for water. With respect to flood and erosion prevention, it is important to improve water retention and infiltration rates in soils to reduce surface run-off. The aim of the study is to quantify the influence of biogenic macropores on infiltration. The effect of the cropping system and management practices on macropore density and infiltration rate was examined. Soil hydraulic conductivity was determined by soil column experiments and field investigations using a hood infiltrometer and rainfall-simulation experiments. Macropores have a great effect on hydraulic conductivity. A large macropore-density results in high infiltration rates. This relationship is described with the skinfactor, applying the Erosion-2D model to adjust infiltration rates. Conservative agricultural management practices show positive effects on earthworm population and hence macropore density. The beneficial effects of no-tillage include less soil disturbance, greater quantities of crop-residues remaining on the soil surface and increased soil moisture.
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