The effect of slope steepness and antecedent moisture content on interrill erosion, runoff and sediment size distribution in the highlands of Ethiopia

Defersha, Mengistu B.; Quraishi, Shoeb; Melesse, Assefa M.

doi:10.5194/hess-15-2367-2011

Cited by 86 publications

(62 citation statements)

References 14 publications

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“…Thus, only the few areas that have limited infiltration capacity produced runoff. These areas are characteristically dry at the beginning of the rainy phase with loose soil and, as shown by Defersha et al (2011), are able to contribute greater amounts of sediment than those contributed from wet soils.…”

Section: Similarity Of All Three Watershedsmentioning

confidence: 99%

Suspended sediment concentration–discharge relationships in the (sub-) humid Ethiopian highlands

Guzmán

Tilahun

Zegeye

et al. 2013

Hydrol. Earth Syst. Sci.

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Abstract. Loss of top soil and subsequent filling up of reservoirs in much of the lands with variable relief in developing countries degrades environmental resources necessary for subsistence. In the Ethiopia highlands, sediment mobilization from rain-fed agricultural fields is one of the leading factors causing land degradation. Sediment rating curves, produced from long-term sediment concentration and discharge data, attempt to predict suspended sediment concentration variations, which exhibit a distinct shift with the progression of the rainy season. In this paper, we calculate sediment rating curves and examine this shift in concentration for three watersheds in which rain-fed agriculture is practiced to differing extents. High sediment concentrations with low flows are found at the beginning of the rainy season of the semi-monsoonal climate, while high flows and low sediment concentrations occur at the end of the rainy season. Results show that a reasonably unique set of rating curves were obtained by separating biweekly data into early, mid, and late rainfall periods and by making adjustments for the ratio of plowed cropland. The shift from high to low concentrations suggests that diminishing sediment supply and dilution from greater base flow during the end of the rainfall period play important roles in characterizing changing sediment concentrations during the rainy season.

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Section: Similarity Of All Three Watershedsmentioning

confidence: 99%

Suspended sediment concentration–discharge relationships in the (sub-) humid Ethiopian highlands

Guzmán

Tilahun

Zegeye

et al. 2013

Hydrol. Earth Syst. Sci.

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“…A 15 cm thick soil layer was then placed on the top and separated from the mineral pumice by a sheet of porous jute (Defersha et al, 2011;Khaledi Darvishan et al, 2014). The soil was ultimately compacted by a PVC roller filled with cement to achieve the bulk density of 1.376 g cm −3 almost equal to that measured for the soil under natural conditions (Khaledi Darvishan et al, 2014).…”

Section: Soil Characteristicsmentioning

confidence: 99%

“…Three layers of mineral pumice grains with different sizes and total thickness of 15 cm were used as a filter layer and placed at the bottom of the plots in order to simulate natural drainage condition and decreasing plot weight (Defersha et al, 2011;Khaledi Darvishan et al, 2014). A 15 cm thick soil layer was then placed on the top and separated from the mineral pumice by a sheet of porous jute (Defersha et al, 2011;Khaledi Darvishan et al, 2014).…”

Section: Soil Characteristicsmentioning

confidence: 99%

“…The collected soil was carried to the lab and air dried to optimum moisture content to maintain the relative stability of the soil aggregates (Kukal and Sarkar, 2011;Khaledi Darvishan et al, 2014;Moreno-Ramón et al, 2014;Brevik et al, 2015). The pebbles and plant residues were removed from the soil by passing it through a 8 mm sieve to obtain maximum similarity with the soil natural conditions (Defersha et al, 2011;Khaledi Darvishan et al, 2014;Ziadat et al, 2013).…”

Section: Soil Characteristicsmentioning

confidence: 99%

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Reducing sediment concentration and soil loss using organic and inorganic amendments at plot scale

et al. 2015

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Abstract. Various organic and inorganic mulches are used for soil conservation purposes, the effectiveness of which on soil characteristics has not been comprehensively considered from different aspects. The present study surveys the efficiency of straw mulch, manure and TA-200 polyacrylamide with respective rates of 500, 300 and 50 g m −2 in changing sediment concentration and soil loss. The experiments were conducted for sandy-loam soil taken from a summer rangeland, the Alborz Mountains, northern Iran. The experiments were performed under laboratory conditions with simulated rainfall intensities of 30, 50, 70 and 90 mm h −1 and a slope of 30 %. The results showed that the straw mulch decreased soil erosion at rate of 45.60 % compared to the control plots and performed better than manure (8.98 % reduction) and PAM (4.74 % reduction). The results showed that the maximum reduction in sediment concentration and soil loss for all soil amendments occurred at the rainfall intensity of 90 mm h −1 with the rates of 58.69 and 63.24 % for straw mulch, 14.65 and 13.14 % for manure and 20.15 and 23.44 % for TA-200.

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“…The collected soil was air-dried to the optimum soil moisture content (Fox and Bryan, 1999). All plant residues and pebbles were removed from the soil (Agassi and Bradford, 1999), and finally the soil was passed through a 8.0 mm sieve (Ekwue and Harrilal, 2010;Defersha et al, 2011;Khaledi Darvishan et al, 2014). The prepared soil was then transferred into the nine plots with the depth of about 15 cm.…”

Section: Installation and Preparation Of Plotsmentioning

confidence: 99%

The impact of standard preparation practice on the runoff and soil erosion rates under laboratory conditions

2016

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Abstract. The use of laboratory methods in soil erosion studies, rainfall simulation experiments, Gerlach troughs, and other measurements such as ring infiltrometer has been recently considered more and more because of many advantages in controlling rainfall properties and high accuracy of sampling and measurements. However, different stages of soil removal, transfer, preparation and placement in laboratory plots cause significant changes in soil structure and, subsequently, the results of runoff, sediment concentration and soil loss. Knowing the rate of changes in sediment concentration and soil loss variables with respect to the soil preparation for laboratory studies is therefore inevitable to generalize the laboratory results to field conditions. However, there has been little attention given to evaluate the effects of soil preparation on sediment variables. The present study was therefore conducted to compare sediment concentration and soil loss in natural and prepared soil. To achieve the study purposes, 18 field 1× 1 m plots were adopted in an 18 % gradient slope with sandy-clay-loam soil in the Kojour watershed, northern Iran. A portable rainfall simulator was then used to simulate rainfall events using one or two nozzles of BEX: 3/8 S24W for various rainfall intensities with a constant height of 3 m above the soil surface. Three rainfall intensities of 40, 60 and 80 mm h −1 were simulated on both prepared and natural soil treatments with three replications. The sediment concentration and soil loss at five 3 min intervals after time to runoff were then measured. The results showed the significant increasing effects of soil preparation (p ≤ 0.01) on the average sediment concentration and soil loss. The increasing rates of runoff coefficient, sediment concentration and soil loss due to the study soil preparation method for laboratory soil erosion plots were 179, 183 and 1050 % (2.79, 2.83 and 11.50 times), respectively.

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The effect of slope steepness and antecedent moisture content on interrill erosion, runoff and sediment size distribution in the highlands of Ethiopia

Cited by 86 publications

References 14 publications

Suspended sediment concentration–discharge relationships in the (sub-) humid Ethiopian highlands

Suspended sediment concentration–discharge relationships in the (sub-) humid Ethiopian highlands

Reducing sediment concentration and soil loss using organic and inorganic amendments at plot scale

The impact of standard preparation practice on the runoff and soil erosion rates under laboratory conditions

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