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The aim of the study was to evaluate the intensity of soil erosion within the catchment of two closed depressions in the Nałęczów Plateau (Lublin Upland). The amount of erosion was assessed from the depth of accumulated soil material, and the calculated amount was related to the time of agricul-tural land use. The studies were carried out in the catchment of the area of 0.54 ha. Within the catchment, 75 intact soil cores were taken and analysed to determine the depth of soil horizons and accumulated soil material. Depositional soils were represented by 25 soil cores. The average thickness of the accumulated material was 0.75 m with a maximum of 1.78 m. The results showed that the catchment of two combined closed depressions evolved to the form of a small valley (trough) after 185 years of agricultural use. The volume of soil material accumulated in the catchment, calculated from the thickness of the depositional material in soil profiles collected in a regular grid, was 1797.4 m3, and the volume calculated from the profiles located in transects that crossed the catchment axis was higher by 2%. The average rate of erosion in the catchment of the two combined depressions was 24.3 Mg ha-1
The objective of this study is to establish a geographical information system method for spatial assessment of soil erosion based on the universal soil loss equation (USLE), and to evaluate the utility of GIS with regard to soil erosion mapping. The study area, Goynuk, covers 1,437 square kilometers and is located in the southeastern part of Bolu, Turkey. In this study, USLE factors including rainfall erosivity (R-factor), soil erodibility (K-factor), slope and slope length (LS-factor), vegetative cover (C-factor), and conservation practice (Pfactor) were studied and reviewed. Each factor, which consists of a set of logically related geographic features and attributes, was used as an input for analysis. A land use map of the study area was generated from (Landsat TM 2000) satellite imagery. A digital elevation model (DEM) interpolated from elevation contours was used to generate the slope and LS-factor. Spatial vegetative cover, extracted from Landsat TM imagery, was used to determine the spatial C-factor and P-factor, values of which are based on experimental results from the literature. USLE model calculation applied to the resultant polygonal layer gave values of soil loss in tons/ha/year. These are then ranked into three classes as low, moderate, and high. The study indicated that highly eroded areas are bare lands and steep conditions, whereas less eroded areas are low slope classes. As a conclusion the study confirms that the use of GIS and remotely sensed data can greatly enhance spatial modeling for soil erosion.
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The use of the information system NIT (Numerical Information about Terrain) for the evaluation of the potential soil water erosion hazard on the river Wieprz basin has been proposed. Maps of the elementary classes of erosion hazards including slope decline, soil cover, geological structure and land use were prepared. The maps were also combined to form a mozaic cartogramme. The information gathered was presented in the form of a scheme and map illustrating the spatial distribution of potential hazards of water erosion in the investigated river Wieprz basin.
The work presents the research results on soil susceptibility to surface wash out, executed on model object (10 experimental plots of different soil kinds in black fallow at terrain slope 10%) in simulated rain (sprinkling) conditions.
Land degradation caused by soil erosion (sheet and rill erosion) and soil fertility decline is a serious threat in the Ethiopian highlands, especially in the Gumara watershed. In this study the SWAT (Soil and Water Assessment Tool) model was applied to the Gumara watershed to predict sediment yield and runoff, to establish the spatial distribution of sediment yield and to test the potential of watershed management measures to reduce sediment loadings from hotspot areas. The model was calibrated using five years of flow and sediment records and validated using data for the next three years. Out of 30 SWAT sub-basins, 18 sub-watersheds (72%) were identified as erosion prone areas contributing to a mean annual sediment load ranging from 11 to 22 t ha-1 yr-1. The model was used to evaluate the potential of vegetation filter strips of various widths to reduce sediment production from critical micro watersheds. The installation of vegetation filter strips on vulnerable land was shown to result in a 58 to 74% reduction in sediment yield for strip widths of 5 m and 10 m respectively.
Máchovo Lake is a historical reservoir founded by Czech King Charles IV. in 14th century. Located in northern part of central Bohemia it has been widely used for recreation purposes for many decades (or even centuries). Its catchments (ca 100 sq km) consist of intensively used agricultural land (ca 25% of area) and of large forested area under nature protection. Several other lakes (ponds) are chained on the two reservoir’s inlets. Irrespective of its great recreation potential Máchovo Lake is one of the Bohemian lakes known for its problems with eutrophication and water quality. The project was set up to point out sources of nutrients and to search for proper solutions. Sediment loads in every lake within the catchments were measured and sampled in order to quantify the nutrients and other pollution. Point and non point sources of phosphorus and other nutrients were searched. Sediment transport within catchments was modelled using WaTEM/SEDEM model. Interestingly, the water quality in the particular ponds varies signifi cantly even though each one of several hundred years old ponds is heavily silted. Soil erosion protection measures within catchments were proposed altogether with flood protection measures in the stream valleys and waste water treatment facilities in surrounding villages. Setting up water quality sampling devices in selected stream profi les was tested and designed. The continual proper management should lead to water quality improvement.
The technique provides for the determination of the size and percentage of aggregates of the coarse fraction on the surface of a friable soil followed by the determination of the aggregation index to be used in assessing spatial and temporal resistance of soil to erosion and defl ation. The uses of this technique make routine sampling and aggregate analysis after Savvinov unnecessary. Its some outcomes for soils of Poland are given.
Erosion factors of a part of Western Serbia, that is, different precipitation amounts and intensities, influencing humus-silicate soil formed on the serpentine, with an 18% inclination toward the northwestsoutheast at the altitude of 300 m, enabled quantitative runoff amounts and soil losses of the fallow and of autochthonous vegetation plot to be defined over a three-year study period. Throughout the trial, the mean annual runoff from the fallow plot amounted to 28.75 l·m⁻², and erosion losses of the soil were 2648.42 g·m⁻². Mean annual runoff and soil losses from the autochthonous vegetation plot were 12.37 l·m-2 and 0.98 g·m⁻², respectively. The total variability of runoff from the fallow plot due to precipitations was 28.1% and that from the plot under autochthonous vegetation was 0.2%. The total variability of soil losses from the fallow plot, due to precipitation, was 43.6% and that from the plot under autochthonous vegetation was 49%.
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