scholarly journals Quantification and Evaluation of Soil Erosion in the Estuaries of Cameroon, Gulf of Guinea: Case of Nylon Area

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Eric Flavien Mbiakouo-Djomo ◽  
Ebénézer Njeugna ◽  
Denis Tcheukam-Toko ◽  
Didier Fokwa
Keyword(s):  
Soil Erosion ◽  
Catchment Area ◽  
Direct Method ◽  
Water Erosion ◽  
Gulf Of Guinea ◽  
Bare Ground ◽  
Average Potential ◽  
High Level ◽  
A Direct Method ◽  
Soil Losses

The area of Nylon represents a sensible and vulnerable environment where water erosion is the cause of many soil losses contributing to the production and movement of sediments from the upstream to the lowest depths. The high level of rainfall in this town, soil texture (sand-clay-silt), and the anarchic occupation of the area play a part in the important deterioration of the bare ground on the upstream of the catchment area. This causes with time an instability of structures and living places which can lead to their progressive disappearance. In order to assess the quantities of displaced sediments, the studies on the quantification of soil moved annually by water erosion are carried out. A direct method is used consisting in using a minisimulator of rain (NEME) in order to understand the phenomena involved and assess the quantity of sediments which can be moved. It helps in assessing erosion caused by the rain and extrapolating results over the catchment area of the chosen field of study. USLE relation has permit to make an extrapolation of the quantity of soil affected, and the result shows that the average potential of loss of soil is 153.57 t/ha/annum.

scholarly journals Soil loss by water erosion in areas under maize and jack beans intercropped and monocultures

2014 ◽  
Vol 38 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Pedro Luiz Terra Lima ◽  
Marx Leandro Naves Silva ◽  
Nilton Curi ◽  
John Quinton
Keyword(s):  
Soil Erosion ◽  
Soil Loss ◽  
Soil Management ◽  
Bare Soil ◽  
Water Erosion ◽  
Management Systems ◽  
Water Runoff ◽  
Jack Bean ◽  
Favorable Conditions ◽  
Soil Losses

Adequate soil management can create favorable conditions to reduce erosion and water runoff, consequently increase water soil recharge. Among management systems intercropping is highly used, especially for medium and small farmers. It is a system where two or more crops with different architectures and vegetative cycles are explored simultaneously at the same location. This research investigated the effects of maize intercropped with jack bean on soil losses due to water erosion, estimate C factor of Universal Soil Losses Equation (USLE) and how it can be affected by soil coverage. The results obtained also contribute to database generation, important to model and estimate soil erosion. Total soil loss by erosion caused by natural rain, at Lavras, Minas Gerais, Brazil, were: 4.20, 1.86, 1.38 and 1.14 Mg ha-1, respectively, for bare soil, maize, jack bean and the intercropping of both species, during evaluated period. Values of C factor of USLE were: 0.039, 0.054 and 0.077 Mg ha Mg-1 ha-1 for maize, jack bean and intercropping between both crops, respectively. Maize presented lower vegetation cover index, followed by jack beans and consortium of the studied species. Intercropping between species showed greater potential on soil erosion control, since its cultivation resulted in lower soil losses than single crops cultivation, and this aspect is really important for small and medium farmers in the studied region.

scholarly journals Application of the pseudoinverse computation in reconstruction of blurred images

Filomat ◽  
2012 ◽  
Vol 26 (3) ◽  
pp. 453-465 ◽  
Author(s):  
Sladjana Miljkovic ◽  
Marko Miladinovic ◽  
Predrag Stanimirovic ◽  
Igor Stojanovic
Keyword(s):  
Mathematical Model ◽  
Direct Method ◽  
Motion Blur ◽  
Linear Motion ◽  
Numerical Examples ◽  
High Level ◽  
Blurred Images ◽  
Programming Package ◽  
A Direct Method ◽  
Very High

We present a direct method for removing uniform linear motion blur from images. The method is based on a straightforward construction of the Moore-Penrose inverse of the blurring matrix for a given mathematical model. The computational load of the method is decreased significantly with respect to other competitive methods, while the resolution of the restored images remains at a very high level. The method is implemented in the programming package MATLand respective numerical examples are presented.

scholarly journals Spatially distributed GIS-realized mathematical model of rainstorm erosion losses of soil

2019 ◽  
Vol 28 (3) ◽  
pp. 562-571
Author(s):  
А. A. Svetlitchnyi ◽  
A. V. Piatkova
Keyword(s):  
Mathematical Model ◽  
Soil Erosion ◽  
Water Balance ◽  
Water Erosion ◽  
Physical Geography ◽  
Forest Steppe ◽  
Spatially Distributed ◽  
Soil Losses ◽  
Slope Runoff ◽  
Distributed Gis

In connection with the wide and ever increasing spread of erosion degradation of agricultural lands in Ukraine, the task of developing mathematical models and methods for calculating water erosion of soils corresponding to the current level of erosion study and the demands of soil protection practices is becoming increasingly important. The article is devoted to the development of a spatially distributed GIS-implemented mathematical model of rainstorm soil erosion, which accounts for most of the annual soil losses (in the Steppe zone, for example, about 90 %). The development of the model is based on the most theoretically and informationally grounded model for the Steppe and Forest-Steppe of Ukraine , “the logical-mathematical model of rainstorm soil outwash” developed by H. I. Shvebs (1974, 1981), as well as the results of theoretical and field studies and mathematical modeling of the slope runoff and water erosion of soil, carried out at the Department of Physical Geography and Environmental Management of Odessa I. I. Mechnikov National University in the 1990s - 2010s, and also the possibilities of modern geoinformation technologies. For the spatial implementation of the model, a raster model of spatial data and operators of the PCRaster GIS-package (University of Utrecht, the Netherlands) were used, integrated with the Basic programming language into a single system that provides an implementation of the computational algorithm. The developed physical-statistical model of soil erosion-sedimentation takes into account the peculiarities of the formation of slope runoff and soil outwash in conditions of excessive nonstationarity of heavy rainfall, as well as spatial heterogeneity of all major natural and economic factors of water erosion on a slope, including slope steepness, exposure, longitudinal and transverse forms of slopes, soil erodibility, structure of sown areas and anti-erosion measures. Checking the adequacy of the mathematical model was performed using observational data of four experimental catchments ; two runoff plots of the Moldavan water-balance station with total area of 0.08 ha, the Ploska catchment with area of 8.5 ha (Boguslav field experimental base of Ukrainian Hydrometeorological Institute) and the Sukha catchment with area of 63 ha (Veliko-Anadol water-balance station) with observation periods of 17-31 years. Comparison of the calculated average over the catchment area of mean annual values of rainstorm soil losses, with the corresponding values obtained from measurements on these catchments, made on the basis of Nash-Sutcliff efficiency criterion (NS), allowed us to evaluate the quality of the model as good (NS = 0.72).

ESTIMATES OF SOIL EROSION AND DEPOSITION FOR SOME SASKATCHEWAN SOILS

1983 ◽  
Vol 63 (3) ◽  
pp. 607-617 ◽  
Author(s):  
E. DE JONG ◽  
C. B. M. BEGG ◽  
R. G. KACHANOSKI
Keyword(s):  
Soil Erosion ◽  
Wind Erosion ◽  
Water Erosion ◽  
Simultaneous Occurrence ◽  
Erosion And Deposition ◽  
The Past ◽  
Middle Slope ◽  
The 1950S ◽  
Wind And Water Erosion ◽  
Soil Losses

137Cs from the atmospheric testing of nuclear devices in the 1950s and 1960s was used to estimate soil erosion in eight small basins in hummocky topography. Three basins had not been cultivated since the 1950s and in these 137Cs showed little or no separation according to landscape position. In the cultivated basins, 137Cs increased from the top to the bottom of the slopes reflecting the simultaneous occurrence of soil erosion on the upper slopes and deposition on the lower slopes. The redistribution of 137Cs was least in a cultivated basin where water erosion was minimal. From the 137Cs it was estimated that over the past 20–25 yr the upper slopes in the cultivated basins had lost 20–60 kg soil/m2, whereas the lower slopes had gained 25–80 kg/m2. Some middle-slope positions lost soil, others gained. An attempt to construct 137Cs and soil balances for each of the cultivated basins was only partially successful. The inability to accurately delineate areas of erosion and areas of deposition is probably the major obstacle in calculating accurate balances for the basins. The 137Cs balances did show promise of being able to separate soil losses by wind and water erosion. Key words: Water erosion, wind erosion, 137Cs, deposition, universal soil loss equation

scholarly journals A Simple Direct Method to Obtain Kinetic Parameters for Polymer Thermal Decomposition

2021 ◽  
Vol 11 (23) ◽  
pp. 11300
Author(s):  
David Lázaro ◽  
Alain Alonso ◽  
Mariano Lázaro ◽  
Daniel Alvear
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Direct Method ◽  
Reaction Model ◽  
Exponential Factor ◽  
Gaseous Fuels ◽  
High Level ◽  
A Direct Method ◽  
Polymer Combustion ◽  
Model Expression

In a fire, the polymer combustion occurs when gaseous fuels react with oxygen. The heating of a material could force the release of gaseous fuels during thermal decomposition and pyrolysis. The rate of pyrolysis to define the gaseous fuels is usually interpreted by means of the Arrhenius expression and a reaction model expression, which are characterized by an activation energy, a pre-exponential factor, and a reaction order value. Many methods are available for determining kinetic parameters from thermogravimetric experimental data. However, the most challenging issue is achieving an adequate balance between accuracy and simplicity. This work proposes a direct method for determining the kinetic parameters with only a thermogravimetric experiment at a single heating rate. The method was validated with six polymers, and the results were compared with those from similar procedures, such as the Lyon method and generalized direct method. The results achieved using the simpler approach of the proposed method show a high level of accuracy.

The soil loss by water erosion at the European part of Russia

2020 ◽  
Author(s):  
Kirill Maltsev ◽  
Oleg Yermolaev
Keyword(s):  
Comparative Analysis ◽  
Soil Erosion ◽  
Soil Loss ◽  
Arable Land ◽  
Water Erosion ◽  
European Part ◽  
The European Union ◽  
Taiga Forest ◽  
European Part Of Russia ◽  
Soil Losses

<p>A quantitative assessment of the potential soil erosion on arable land in the European part of Russia (EPR) was carried out. The total area of arable land of the EPR is about 650,000 km<sup>2</sup>. The majority of the population of Russia lives here - about 95 million people. The level of generalization of work is regional and corresponds to a scale of 1: 500,000.</p><p>As a research method, mathematical modeling based on modified for Russia’s natural conditions USLE equation for calculating potential soil loss from erosion. Another leading method for assessing soil erosion and presenting results is GIS. A raster model of data presentation was used in the calculations, including a model of slope angles, slope lengths, soil erodibility, erosive rainfall potential, water reserves in snow, intra-annual redistribution of rainfall, and land use types.</p><p>New data have been obtained on the value of soil erosion losses during melt and storm runoff periods and total annual losses. An electronic map of soil erosion losses on arable lands of the European part of Russia has been compiled, which allows determining spatial features of soil erosion rates.</p><p>The average soil erosion losses, taking into account the soil-protective coefficients of agricultural crops for the study area, are 4.04 t / ha per year. In annual soil losses due to erosion, storm 3.78 prevails, soil loss from melt water is almost an order of magnitude less - t / ha 0.26. About half of the territory is located in conditions under which the soil loss does not exceed 0.5 t / ha per year.</p><p>The rate of potential soil erosion on arable land in the European part of Russia naturally decreases in the direction from the taiga-forest to the steppe landscape zone. The band of maximum potential soil erosion of the west-east sub-latitudinal strike is clearly distinguished, confined to the subzone of mixed and broad-leaved forests with very high plowing. A comparative analysis of our data and data obtained in the mid-1980s showed a reduction in soil loss from water erosion in all landscape zones. In addition, a comparative analysis of the data obtained by us and the data for the European Union was carried out, which showed that the soil losses on the EPR are slightly higher.</p>

Sources of Nitrogen and Phosphorus in the Catchment Area of Neusiedlersee/Fertö, Austria/Hungary

1993 ◽  
Vol 28 (3-5) ◽  
pp. 101-110 ◽  
Author(s):  
W. v. d. Emde ◽  
H. Fleckseder ◽  
N. Matsché ◽  
F. Plahl-Wabnegg ◽  
G. Spatzierer ◽  
...  
Keyword(s):  
Point Source ◽  
Catchment Area ◽  
Management Practice ◽  
Water Erosion ◽  
Nonpoint Source ◽  
Point Sources ◽  
Source Control ◽  
Nitrogen And Phosphorus ◽  
Catchment Areas ◽  
The One

Neusiedlersee (in German) / Fertö tó (in Hungarian) is a shallow lake at the Austro-Hungarian border. In the late 1970s, the question arose what to do in order to protect the lake against eutrophication. A preliminary report established the need for point-source control as well as gave first estimates for non-point source inputs. The proposed point-source control was quickly implemented, non-point sources were - among other topics - studied in detail in the period 1982 - 1986. The preliminary work had shown, based on integrated sampling and data from literature, that the aeolic input outweighed the one via water erosion (work was for totP only). In contrast to this, the 1982 - 1986 study showed that (a) water erosion by far dominates over aeolic inputs and (b) the size of nonpoint-source inputs was assessed for the largest catchment area in pronounced detail, whereas additional estimates were undertaken for smaller additional catchment areas. The methods as well as the results are presented in the following. The paper concludes with some remarks on the present management practice of nonpoint-source inputs.

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