Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

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Agriculture contributes about 70 percent of Malawi's Gross Domestic Product and sustains the livelihood of over 85 percent of the rural population. Soil erosion, which has reached alarming proportions, is threatening this resource base. Despite being rated the most serious environmental problem, soil erosion research lags behind in the listing of agricultural research priorities, particularly with regard to factors influencing the implementation of soil conservation policy and legislation. This study aimed to assess the impact of such policy implementation on smallholder farmer soil conservation practices. A postal, self administered, structured questionnaire was used to interview twenty-three farmers and fourteen agricultural extension staff members. The questions were designed to assess the influence of their perceptions of soil erosion as a problem and its causes. They also sought to assess how effectively relevant policy had been implemented before and after independence. Socio-economic information was additionally elicited from the farmers. After preliminary analysis of these questionnaires, ten days was spent in the field verifying data collected. A Spearman's Rank correlation analysis at 95 percent confidence level was carried out between various components of the farmers' socioeconomic profile data and their responses to the perception questions. Perceptions regarding different aspects of soil erosion and conservation were found to be influenced by the sex, age and educational level of respondents. The study revealed that both farmers and extension staff perceived soil erosion as a problem, had a sound knowledge of the mechanics of the process and attributed it to anthropogenic factors. While both farmers and extension staff attributed declining yields and fertility to accelerated soil erosion, they appeared to have difficulty in identifying physical indicators of such activity in the field. The study also revealed that both believed the top-down approach of the pre-independence period and the post-independence to 1990 period, had been partially effective. Since 1990, policy implementation has become more effective as a result of a more democratic governance and increased extension staff awareness of sustainability concepts which stress the need to incorporate the aspirations of farmers in a bottom-up implementation. This awareness led to the formulation of a new soil and water conservation policy in 1996 which ensures the voices of decision makers are taken into account in policy review. Once legislated, this policy bodes well for further improvements in soil conservation efforts in Malawi. However, the study also revealed that effective implementation of this policy will be dependent on the government providing adequate support and skills to both extension staff and farmers. / Thesis (M.Sc.)-University of Natal, Durban, 2003.

Soil material exported from river catchments by soil erosion is a key issue in environmental sustainability. Although soil erosion processes have been thoroughly investigated, their dynamics, specifically the continuity of erosion processes and sediment source locality, are less studied. The aim of this investigation was to evaluate the changes in the fluxes and characteristics of sediments during their downslope and downstream transport. The study was conducted in a 1000 ha catchment of the Drakensberg foothills, South Africa. Sediment fluxes were monitored at nested scales during the 2009-2011 rainy seasons using 1×1m and 2×5 m erosion plots and H-flumes coupled to automatic samplers from 23 ha, 100 ha catchments. In addition, soil texture, colour and total organic carbon and nitrogen contents in sediments exported from the nested scales and a 1000 ha catchment were compared to in-situ surface and sub-surface soil horizons in a 23 ha catchment river bank and hillslope soils and fluvial sediments. There was a sharp increase of sediment fluxes with increasing slope length (846±201 gm-1y-1 for 1 m2 vs 6820±1714 gm-1y-1 for 10 m2), revealing a limited contribution of splash erosion compared to rain-impacted flow erosion. Sediment fluxes decreased to 500±100 gm-1y-1 and 100±10 gm-1y-1 at the 23 ha and 100 ha catchments respectively, indicating the occurrence of sedimentation during sediment downslope and downstream transport. A principal component analysis (PCA) suggested that rain impacted flow erosion efficiency at the 10 m2 scale was significantly correlated with soil bulk density, clay content and antecedent rainfall (P<0.05). Moreover, strong correlations existed between runoff, sediment concentration and soil loss and selected soil surface and environmental variables at the plot scales. Correlations became weaker at the catchment scales due to increasing landscape heterogeneity and the complexity of soil erosion dynamics. An additional PCA suggested that stream bank erosion contributed to 63% of the soil loss from the 23 ha catchment. During their downstream transport, sediments were discriminated by the second PCA axis, which correlated with the clay and fine silt content, 100 ha sediments showed negative coordinates to this axis while 1000 ha catchment sediment had positive coordinates. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

Subsurface solutional pathways make limestone terrains sensitive to changes in soil properties that regulate flows to the epikarst. This study examines biogeomorphic factors responsible for changed water movements and erosion in fluviokarst slopes deforested 200 years ago along the Kentucky River, Kentucky. In this project, infiltration and water content data from forest and fescue grass soil profiles were analyzed within a detailed overview of system factors regulating hillslope hydrology. Results show that grass has growth and rooting characteristics that tend to create a larger volume of lateral water movement in upper soil layers than occurs under forests. This sets up the current emergent pattern of erosion in which water perches at grass slope bases and overwhelms pre-existing epikarst drainage. Tree roots are able to cause solution at multiple discrete points of entry into fractures and bedding planes, increasing storage capacity and releasing sediment over time. Grass roots do not enter bedrock, and their rooting depth limits diffuse vertical preferential flow in root channels to above one meter. In the areas dense clay soils, flow under grass is conducted sideways either through the regolith or at the bedrock surface. Rapid flow along rock faces in hillslope benches likely moves fines via subsurface routes from the hillslope shoulders, causing the exposure of flat outcrops under grass. Lower growing season evapotranspiration also promotes higher grass summer flow volumes. Gullying occurs at sensitive points where cutters pass from the uphill grassed area into the forest, or where flow across the bedrock surface crosses grass/forest boundaries oriented vertical to the slope. At these locations, loss of the protective grass root mat, coupled with instigation of tree root preferential flow in saturated soils, causes soil pipes to develop. Fluviokarst land management decisions should be based on site-specific slope, soil depth, and epkarst drainage conditions, since zones sensitive to erosion are formed by spatial and temporal conjunctions of a large number of lithologic, karst, soil, climate, and vegetation factors. This study shows that it is the composite of differing influences created by forest and grass that make forests critical for soil retention in high-energy limestone terrains.

Für die Erstellung von Bewirtschaftungs- und Maßnahmenplänen (FFH, EU-WRRL) ist es erforderlich, den bislang noch sehr hohen Aufwand für die Datenbeschaffung und -generierung im Rahmen der Modellierung mit EROSION 3D zu senken. Erreicht werden soll eine schnellere sowie effizientere Abschätzung von Landnutzungsänderungen, Landschaftseingriffen, des Klimawandels usw. auf Oberflächenabfluss, Bodenabtrag sowie Sedimenteintrag in Gewässer mit EROSION 3D. Im vorliegenden Projekt ist es gelungen, Parametrisierung und Modellanwendung so zu kombinieren, dass eine Bodenabtragssimulation mit dem Modell EROSION 3D flächendeckend für Sachsen mit vertretbarem Zeitaufwand durchführbar ist. Der korrigierte und angepasste Geo-Basisdatensatz liefert die Primärinformationen zur Datenbankabfrage der Parametrisierungssoftware DPROC. Durch eine interaktive Flächenauswahl, kombiniert mit einem Flächendatenzuschnitt, können Landnutzungs- und Bearbeitungsszenarien für hydrologische Einzugsgebiete oder Oberflächenwasserkörper schnell parametrisiert werden. Die grundlegend korrigierte und erweiterte Datenbank des DPROC erlaubt die verbesserte Abschätzung erosionsrelevanter Bodenparameter, besonders für die dauerhaft konservierende Bodenbearbeitung und die Direktsaat. Die umfangreiche Dokumentation der Arbeitsschritte und die Transparenz der Datenbank ermöglichen es, jederzeit Aktualisierungen (Geo-Basisdaten) und Erweiterungen (DPROC-Datenbank) vorzunehmen. Von den Projektergebnissen profitieren vor allem die Anwender des Programms EROSION 3D. Beim Druck des Dokumentes ist zu beachten, dass die Karten im Format DIN A3 erstellt wurden.

Corrigenda pasted onto front end-paper. / Bibliography: leaves 307-326. / xvii, 326 leaves : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / A study was undertaken of erosion and sedimentation in a catchment in South Australia. An erosion and sedimentation model was developed and interfaced with the existing digital terrain models called TAPES-C and THALES, to estimate soil erosion and deposition in Sauerbier Creek catchment. / Thesis (Ph.D.)--University of Adelaide, Dept. of Civil and Environmental Engineering, 1999?

Corrigenda pasted onto front end-paper. / Bibliography: leaves 307-326. / xvii, 326 leaves : ill., maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / A study was undertaken of erosion and sedimentation in a catchment in South Australia. An erosion and sedimentation model was developed and interfaced with the existing digital terrain models called TAPES-C and THALES, to estimate soil erosion and deposition in Sauerbier Creek catchment. / Thesis (Ph.D.)--University of Adelaide, Dept. of Civil and Environmental Engineering, 1999?

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 6, 2007) Includes bibliographical references.