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The methodological aspect investigation of intensity of chemical erosion  [PDF]
Manojlovi? Predrag A.
Glasnik Srpskog Geografskog Dru?tva , 2002, DOI: 10.2298/gsgd0202035m
Abstract: Researching of intensity of chemical erosion nowadays includes different methods, which can be divided into three groups: laboratory experiments, terrain experiments and empirical methods. This work analyses some methods and results that are obtained by their use.
Contribution to the research of the chemical intensity erosion in the western Serbia
Dragi?evi? Slavoljub,Manojlovi? Predrag A.,Mustafi? Sanja
Glasnik Srpskog Geografskog Dru?tva , 2003, DOI: 10.2298/gsgd0301007d
Abstract: Based on the research of the chemical erosion intensity in the upper course of Tamnava, the appearance of its negative value has been found. Further researches, that enclose the lower course, confirmed this fact. This research opened the important question about the causes of this phenomena. Analytical method eliminated all expected causes and led to conclusion that the reason for this should be found by using the more precise research of the mineralisation of the precipitations. It was necessary to continue the measurings of the precipitation mineralisation in the greater number of locations and in the wider time period, as well as in the different meteorological conditions, and after that to establish the subordination between the amount of precipitations and the entered TDS. Only after these additive researches we could be able to find out the relation between ''entry'' and ''exit'' and to find out the intensity of the chemical erosion in this, and in the other river basins. For now, we are able only to find out the carrying of TDS, as well as the reduction of the chemical evacuation for the non - carbonated part of the basin (corrected value).
Excess erosion and deposition in the catchments of Kamenichka and Radanjska river, Republic of Macedonia  [PDF]
Milevski Ivica
Glasnik Srpskog Geografskog Dru?tva , 2009, DOI: 10.2298/gsgd0904109m
Abstract: One of the greatest environmental problems in the Republic of Macedonia is accelerated soil erosion caused by high human impact during last centuries on to the susceptible landscape. Natural factors itself are very suitable for development of such erosion: from mostly erodible rocks and soils on the mountainous slopes around the depressions, to the generally continental, semi-arid climate and slight vegetation cover. Because of that, there are sites with severe erosion and deposition like those in the catchments of Kamenichka River and Radanjska River, two torrential tributaries of Bregalnica. In these catchments there are varieties of erosion-related landforms: rills, gullies, badlands, landslides, as well as valley-type alluvial fans and huge alluvial plains. Such devastating accelerated erosion and deposition largely transformed original landscape, and represent significant environmental, social, and economic problem in local areas. Because of that, some measures of protection and conservation were taken from 1950-ties in both catchments. But it is obvious that the final effect of these measures is far of enough, so new efforts must be implemented to revitalizing these abandoned lands.
The erosion intensity changes in Zaje ar municipality  [PDF]
Dragi?evi? Slavoljub,Novkovi? Ivan,Milutinovi? Milena
Glasnik Srpskog Geografskog Dru?tva , 2009, DOI: 10.2298/gsgd0904003d
Abstract: Apart from other geomorphologic processes (glacial erosion, nivation, abrasion) which are predominantly determined by the intensity of natural factors, soil erosion is significantly determined by anthropogenic influences. Despite the fact that the physical-geographic factors are important determinants of the erosion intensity this geomorphologic process has also demographic, socio-economic, environmental, and multidisciplinary aspects as well. Control works, some demographic characteristics of the territory and the type of land use are the direct and indirect anthropogenic influences and modifiers of the intensity of this process. The basic idea of this paper is to assess the basic socio-geographic change over certain area and to determine its effects on the erosion intensity.
A PROPOSED APPROACH OF SEDIMENT SOURCES AND EROSION PROCESSES IDENTIFICATION AT LARGE CATCHMENTS
Preksedis Marco Ndomba,Felix W. Mtalo,?nund Killingtveit
Journal of Urban and Environmental Engineering , 2007,
Abstract: In the subject of identifying sediment sources and erosion processes at catchment level researchers have proposed various methods. Most of the techniques have been applied in isolation. A few workers have combined some methods but still they could not ascertain their findings. As a result they recommended more sophisticated methods in order to compare the results. Little however has been done to correlate suspended sediment concentrations using spatial and temporal hydrological variables like rainfall and surface runoff at reasonable time step such as daily time series. In this study selected methods by previous workers are used and compared. The hydrological variables mapping technique has complemented the results of various renowned sediment sources identification techniques. The introduced method gives not only probable sources and processes but also it additionally identifies location based sediment sources using rainfall stations as pointers. The combined results from both methods indicate that either clay soil land plots or agricultural areas are potential sediment source areas. The result is comparable to previous researchers’ findings in the Pangani River basin that mapped the erosion zones using simple empirical and complex physics-based mathematical models. Although, the methods adopted in this study lacked high-resolution data, the authors believe that the methods and modifications applied give a quick, reliable and more insight to future sediment yield modelling efforts at a catchment level. For instance, a distributed watershed sediment yield model would be appropriate based on high spatial and temporal variation of the hydrological variables as reported in this study. Also, the results suggest that Sediment yield model that simulates sheet erosion might be an ideal tool since the major source areas of the transported sediment are topsoils or sheet erosion.
On-Site Effects and Cost of Fertility Erosion from Five Small Reservoir Catchments in the Upper East Region of Ghana
BK Amegashie, C Quansah, AW Agyare, M Bonsu, SN Odai
Journal of Science and Technology (Ghana) , 2012,
Abstract: A study was carried out in the Upper East Region of Ghana to assess the on-site effects and the cost of fertility erosion from five small reservoir catchments (Dua, Doba, Zebilla, Kumpalgogo and Bugri). The catchment soils and reservoir sediments were sampled and analyzed for their bulk density and nutrient content. The mean reduction in soil depth in the various catchments was 3.996±3.806 mm y-1 in the order of Kumpalgogo>Dua>Bugri>Zebilla>Doba. The corresponding decrease in the water holding capacity of the top 20 cm depth of the catchment soils ranged from 0.563 to 4.698 % per year. The percentage loss in the total nutrient stocks in the top 20 cm of the catchments as eroded sediment-bound nutrients ranged from 9.63 to 64.71, 7.87 to 56.83, 6.12 to 54.82, 1.26 to 40.14, 49.86 to 12.65, 16.84 to 72.07 for OC, N, P, K, Ca and Mg, respectively. The total amount of nutrient loss in kg ha-1 among the reservoirs ranged from 2383 to 19672 for OC, 153 to 3048 for N, 3.15 to 42.59 for P, 41 to 290 for K, 432 to 2158 for Ca, and 63 to 483 for Mg. The cost of N, P and K removed by erosion was calculated by the Replacement Cost Method. The total cost per year (GH¢ ha-1 y-1) of fertilizers (sulphate of ammonia, single superphosphate and muriate of potash) was 286.15 for Dua, 74.289 for Doba, 225.061 for Zebilla, 1119.997 for Kumpalgogo and 96.376 for Bugri. The study has amply shown that soil loss through erosion reduces top soil depth, nutrient stocks and the water holding capacity of catchment soils. This will adversely affect crop productivity if no control measures are implemented. This can also lead to land degradation.
Changes of the intensity of Ljig river basin erosion: Influence of anthropogenic factor  [PDF]
Dragi?evi? Slavoljub,Stepi? Milomir
Glasnik Srpskog Geografskog Dru?tva , 2006, DOI: 10.2298/gsgd0602037d
Abstract: According to new field investigations as well as mapping of erosion in Ljig river basin we have found out that its intensity has changed in regard to period of 40 years ago. The most expressive changes were noticed in Ljig river basin. As we have not noticed changes in physical-geographical factors the cause of the intensity decrease might be only influenced by indirect anthropogenic factor. Processes of growing old and decrease of rural population, migration village-town, marginalization of agriculture and decrease of cattle reserves caused the changes of land utilization. Agriculture areas were becoming overgrown with growing wild vegetation which restrained gradually considerable expressed processes of erosion in the past.
Evaluate the Accuracy of Fargas and BLM Models for Identification of Erosion Intensity  [PDF]
Naser Abdi
Open Journal of Geology (OJG) , 2016, DOI: 10.4236/ojg.2016.611103
Abstract: Erosion process not only changes the land use to badlands, but also produces sediments that are dumped in the dam reservoirs, reduces the reservoir volume and finally makes it useless. So, it is necessary to do study on erosion intensity and the sediment production evaluation for which there are some methods and models. The experimental Fargas and BLM models are largely used for this issue, in Iran as well as many other countries, separately or together based on the data availability. These studies results are as data for sediment supply estimation in different watershed management studies. So, the result accuracy is important for determination of sediment occurrence. This study evaluates these models’ results accuracy, in order to find the limitations and any solutions. Therefore, these two models were used and run in the same area, Aghbolagh drainage basin, Iran; the results were compared and evaluated. These models are based on some factors like rock type, drainage density, surface erosion and litter cover. The study includes field and laboratory analysis. The data were combined in GIS software and processed. The results reveal that, Fargas model predicts 3.67%, 14.26% and 81.06% of the area susceptible for high, severe and very severe erosion respectively; whilst, referring to BLM model outcome, 42.96% area has high sensitivity; 42.96% and 24.94% of the area have high and severe sensitivity for erosion, respectively. Furthermore, both models show same severity for around 18% of the study area. So, for these two models results very low similarities are concluded, which could be an indication of low reliability of the results, especially when they are used separately without any combination or comparison. Finally, it is recommended to use both of them together, or use another method beside each mentioned models.
Erosion, deposition and replacement of soil organic carbon in Mediterranean catchments: a geomorphological, isotopic and land use change approach  [PDF]
E. Nadeu,A. A. Berhe,J. de Vente,C. Boix-Fayos
Biogeosciences Discussions , 2011, DOI: 10.5194/bgd-8-8351-2011
Abstract: The assessment of the net effect of soil erosion on the global carbon budget is still incomplete because of lack of enough focused studies and field data. Two of the major gaps on our understanding of the erosion induced terrestrial carbon sink issue include rate of eroded soil organic carbon (OC) replacement by production of new photosynthate and stability of eroded OC post deposition. Here we examine the effect of erosion processes and land use change on the stock, type and stability of OC in two medium-sized subcatchments (18 and 50 ha in size) in SE Spain. We analysed soil samples from drainage areas and depositional settings for stock and isotopic composition of OC (14C and 13C) and particle size distribution. In addition, we conducted land use change analysis for the period 1956–2008 and a geomorphological survey of the current erosion processes taking place in the slope-streambed connections. Our findings demonstrate how land use change influenced the dominating erosion processes and, thus, the source of eroding sediments. Carbon isotopes used as tracers revealed that in one of the subcatchments the deposited sediments derived from deep soil (average Δ14C of 271.5 ‰) through non-selective erosion processes. In the other subcatchment, topsoil material was predominantly eroded and the average Δ14C in sediments was 64.2 ‰. Replacement of eroded soil OC was positive (4 and 11 times-fold losses by erosion) for the analyzed soil profiles in the slopes suggesting that erosion processes do not necessarily provoke a decrease in soil OC stock.
Erosion, deposition and replacement of soil organic carbon in Mediterranean catchments: a geomorphological, isotopic and land use change approach
E. Nadeu, A. A. Berhe, J. de Vente,C. Boix-Fayos
Biogeosciences (BG) & Discussions (BGD) , 2012,
Abstract: Determination of whether soil erosion can constitute a net terrestrial carbon dioxide (CO2) sink continues to suffer from lack of sufficient focused studies and field data. Two of the major gaps in our understanding of the erosion induced terrestrial carbon sink issue include rate of eroded soil organic carbon replacement by production of new photosynthate and stability of eroded organic carbon (OC) post deposition. Here we examined the effect of erosion processes and land use change on the stock, type, and stability of OC in two medium-sized subcatchments (18 and 50 ha in size) in SE Spain. We analysed soil samples from drainage areas and depositional settings for stock and isotopic composition of OC (14C and 13C), and particle size distribution. In addition, we conducted land use change analysis for the period 1956–2008 and a geomorphological survey of the current erosion processes taking place in the slope-streambed connections. Our findings demonstrate that land use change influenced the dominating erosion processes and, thus, the source of eroding sediments. Carbon isotopes used as tracers revealed that in one of the subcatchments the deposited sediments were derived from deep soil (average Δ14C of 271.5 ‰) through non-selective erosion processes and channel incision. In the other subcatchment, topsoil material was predominantly eroded and the average Δ14C in sediments was 64.2 ‰. Replacement of eroded soil OC was taking place in the analysed soil profiles in the slopes suggesting that erosion processes do not necessarily provoke a decrease in soil OC stock over time.
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