scholarly journals Runoff and soil loss responses of cultivated land managed with graded soil bunds of different ages in the Upper Blue Nile basin, Ethiopia

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Mengie Belayneh ◽  
Teshome Yirgu ◽  
Dereje Tsegaye

Abstract Background In view of a wide range of on-site and off-site impacts of soil erosion, different soil and water conservation measures have been implemented mainly over the last two decades in the Gumara watershed and Ethiopia at large. But their effects have not been sufficiently documented, and maintenance of structures received very little attention. This study investigated the effectiveness of graded soil bunds of zero and 11 years of age in reducing runoff and soil loss. Six hydrologically isolated experimental runoff plots (three treatments × two replicates) were prepared to observe rainfall, runoff, and sediment concentrations in the 2019 summer rainfall season (covering approximately 70% of the annual rainfall). Results Newly constructed soil bunds reduced runoff by 34.94 and 25.56% compared to the old and non-treated counterparts, respectively. Similarly, 59.6 and 48.3% soil loss reductions were observed. The amount of soil loss in non-treated plots was twice that from the new plots and even 1.6 times higher than that from the old-graded soil bund treatments. The rate of soil loss in the new- and old-graded soil bund-treated and non-treated plots was 23.5, 45.6, and 58.1 t ha−1 year−1, respectively. However, the effectiveness of the old soil bunds was much lower (only − 12.6 and − 21.7% in runoff and soil loss, respectively) than its new equivalent. Graded soil bunds, in its new form, reduced runoff, runoff coefficient, and soil loss significantly (P < 0.05). Regardless of the treatments, from the start of the rainy season to the end, runoff and runoff coefficient showed an increase, but sediment concentration decreased. Newly constructed soil bund is the most effective in reducing runoff and soil loss. Conclusion Graded soil bunds reduced runoff and soil loss significantly, but the rate even in the treated plots was very high when compared to both the soil loss tolerance (1–6 t ha−1 year−1) and formation rate (10–14 t ha−1 year−1) estimated for the area. Hence, these structures need to be supported by other measures such as grass strips, agro-forestry, and percolation ditches, for better results. Besides, regular maintenance by either removing sediments from bund furrows or increasing the bund height is recommended for sustained reduction of runoff and soil loss.

2014 ◽  
Vol 6 (2) ◽  
pp. 2915-2938 ◽  
Author(s):  
S. H. R. Sadeghi ◽  
L. Gholami ◽  
E. Sharifi Moghadam ◽  
A. Khaledi Darvishan

Abstract. Amendments can control the runoff and soil loss by protecting soil surface. However, scale effects on runoff and soil loss control has not been considered yet. The present study has been formulated to determine the efficiency of two plot sizes of 6 and 0.25 m2 covered by straw mulch with rate of 0.5 kg m−2 in changing the time to runoff, runoff coefficient, sediment concentration and soil loss under laboratory conditions. The study has been conducted for a sandy-loam soil taken from summer rangeland, Alborz Mountains, Northern Iran under simulated rainfall intensities of 50 and 90 mm h−1 and in 3 replicates. The results of the study showed that the straw mulch had more significant effect in in reducing runoff coefficient, sediment concentration and soil loss at 0.25 m2 plot scale. The maximum effectiveness in time to runoff for both the scales, observed in rainfall intensity of 90 mm h−1. The maximum increasing and decreasing rates in time to runoff and runoff coefficient observed in the rainfall intensity of 90 mm h−1 with the amounts of 367.92 and 96.71% for 0.25 m2 plot and the amounts of 110.10 and 15.08% for 6 m2 plot respectively. The maximum change of soil loss in both the intensities of 50 and 90 mm h−1 occurred at 0.25 m2 plot with the amount of 100% whereas at 6 m2 plot, decreasing rates of soil loss for in both the intensities of 50 and 90 mm h−1 were 46.74 and 63.24%, respectively.


Solid Earth ◽  
2015 ◽  
Vol 6 (1) ◽  
pp. 1-8 ◽  
Author(s):  
S. H. R. Sadeghi ◽  
L. Gholami ◽  
E. Sharifi ◽  
A. Khaledi Darvishan ◽  
M. Homaee

Abstract. Amendments can control the runoff and soil loss by protecting the soil surface. However, scale effects on runoff and soil loss control have not been considered yet. The present study has been formulated to determine the efficiency of two plot sizes of 6 and 0.25 m2 covered by 0.5 kg m−2 of straw mulch with regard to changing the time to runoff, runoff coefficient, sediment concentration and soil loss under laboratory conditions. The study used a sandy-loam soil taken from summer rangeland, Alborz Mountains, northern Iran, and was conducted under simulated rainfall intensities of 50 and 90 mm h−1 and in three replicates. The results of the study showed that the straw mulch had a more significant effect on reducing the runoff coefficient, sediment concentration and soil loss on a 0.25 m2 plot scale. The maximum effectiveness in time to runoff for both the scales was observed at a rainfall intensity of 90 mm h−1. The maximum increasing and decreasing rates in time to runoff and runoff coefficient were observed at a rainfall intensity of 90 mm h−1, with 367.92 and 96.71% for the 0.25 m2 plot and 110.10 and 15.08% for the 6 m2 plot. The maximum reduction in the runoff coefficient was in the 0.25 m2 plot for the two rainfall intensities of 50 and 90 mm h−1, with rates of −89.34 and −96.71%. The maximum change in soil loss at the intensities of both 50 and 90 mm h−1 occurred in the 0.25 m2 plot, with 100%, whereas in the 6 m2 plot, decreasing rates of soil loss for the intensities of both 50 and 90 mm h−1 were 46.74 and 63.24%, respectively.


2018 ◽  
Vol 46 (2) ◽  
pp. 553-562 ◽  
Author(s):  
Ataollah KAVIAN ◽  
Leila GHOLAMI ◽  
Maziar MOHAMMADI ◽  
Velibor SPALEVIC ◽  
Moghadeseh FALAH SORAKI

Soil erosion is one of the key challenges in soil and water conservation. Vegetation that covers soil and organic and inorganic mulch is very useful for the control of erosion processes. This study examined treatment with wheat residual (as agriculture mulch) on infiltration, time to runoff, runoff coefficient, sediment concentration and soil erosion processes. The study has been conducted for sandy-loam soil taken from summer rangeland (Northern Iran) with simulated rainfall intensities of 50 and 100 mm h-1. The experiment was conducted in slopes of 30% in three replications with two amounts of wheat residual of 50 and 90 %. The results showed that conservation percent of soil erosion for wheat residual 50 and 90% was 61.68 and 73.25%, respectively (in rainfall intensity of 50 mm h-1). Also, the conservation percent of soil erosion for wheat residual of 50 and 90% cover was 70.68 and 90.55, respectively (in rainfall intensity of 100 mm h-1). It was concluded that the conservation treatments could reduce runoff coefficient, sediment concentration and soil erosion and increase the time to runoff and infiltration coefficient. This effect was significant on time for infiltration, sediment concentration and soil erosion variables (R2=0.99), time to runoff and runoff coefficient variables (R2=0.95). The interaction effects of rainfall intensity and soil conservation was significant for sediment concentration and soil erosion variables (R2=0.99).


2013 ◽  
Vol 34 (3) ◽  
pp. 236-259 ◽  
Author(s):  
Gebeyehu Taye ◽  
Jean Poesen ◽  
Bas Van Wesemael ◽  
Matthias Vanmaercke ◽  
Daniel Teka ◽  
...  

2012 ◽  
Vol 58 (No. 8) ◽  
pp. 337-344 ◽  
Author(s):  
A. Parsakhoo ◽  
M. Lotfalian ◽  
A. Kavian ◽  
S.A. Hosseini ◽  
M. Demir

The effects of Rubus hyrcanus L. and Philonotis marchica (Hedw.) Bridon on runoff generation and soil loss from cutslopes of forest roads were investigated. The study was conducted at the northern forest of Iran, about 30 km south of the city of Sari. Runoff and sedimentation after each rainfall simulation and chemical and physical soil properties were measured in 14 plots with an area of 0.48 m<sup>2</sup>. The obtained results indicate that the vegetation dominated by Philonotis marchica exhibited the higher runoff coefficient and soil loss, with averages of 27.25% and 92.40&nbsp;g&middot;m<sup>&ndash;2</sup>&middot;h<sup>&ndash;1</sup>(gram per square meter per hour), respectively, in comparison to Rubus hyrcanus. For Philonotis marchica (Hedw.) Brid. the sediment concentration increased quickly at the beginning of rainfall simulations and after 10&ndash;12 min there was a fast decrease in sediment concentration. The peak of sediment concentration was for the Rubus hyrcanus L. in the 13<sup>th</sup>&ndash;15<sup>th</sup> min In conclusion, Rubus hyrcanus L. prevented or decreased the risk of runoff and soil loss from cutslopes of forest roads in our study area. &nbsp;


1983 ◽  
Vol 63 (2) ◽  
pp. 271-280 ◽  
Author(s):  
G. J. WALL ◽  
J. GREUEL ◽  
W. T. DICKINSON

The use of the universal soil loss equation in Canada to estimate soil loss potential for soil and water conservation planning purposes has been limited by the lack of published rainfall erosion indices and by the arduous procedure generally accepted for determination of these indices. This study was conducted to develop and test relatively simple methods to develop annual rainfall erosion indices and associated seasonal distribution patterns. An approach to the determination of a rainfall-runoff factor to accommodate the effect of winter conditions has also been included. The relatively simple techniques for estimating average annual rainfall erosion indices and seasonal distribution patterns of rainfall erosion have been found to yield comparable values to those determined by more tedious methods. These erosion indices and associated distribution patterns have proven useful for the development of a first approximation of rainfall erosion maps for Canadian locations east of the Rocky Mountains. Key words: Rainfall erosion indices, USLE


2014 ◽  
Vol 22 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Leila Gholami ◽  
Kazimierz Banasik ◽  
Seyed Hamidreza Sadeghi ◽  
Abdulvahed Khaledi Darvishan ◽  
Leszek Hejduk

Abstract Mulches have extraordinary potential in reducing surface runoff, increasing infiltration of water into the soil and decreasing soil erosion. The straw mulches as a biological material, has the ability to be a significant physical barrier against the impact of raindrops and reduce the detachment of soil aggregates. The present study is an attempt to determine the efficiency of straw mulch as conservation treatment in changes in the splash erosion, time-to-runoff, runoff coefficient, infiltration coefficient, time-to-drainage, drainage coefficient, sediment concentration and soil loss. The laboratory experiments have been conducted for sandy-loam soil taken from deforested area, about 15 km of Warsaw west, Poland under lab conditions with simulated rainfall intensities of 60 and 120 mmh–1, in 4 soil moistures of 12, 25, 33 and 40% and the slope of 9%. Compared with bare treatments, results of straw mulch application showed the significant conservation effects on splash erosion, runoff coefficient, sediment concentration and soil loss and significant enhancement effects on infiltration and drainage. The results of Spearman-Rho correlation showed the significant (p < 0.05) correlation with r = –0.873, 0.873, 0.878 and 0.764 between rainfall intensity and drainage coefficient, downstream splash, sediment concentration and soil loss and with r = –0.976, 0.927 and –0.927 between initial soil moisture content and time-to-runoff, runoff coefficient and infiltration coefficient, respectively.


Author(s):  
Jianbo LIU ◽  
Guangyao GAO ◽  
Shuai WANG ◽  
Bojie FU

ABSTRACTThe purpose of this paper was to study the interaction effects of rainfall regime and slope length on runoff and soil loss under different land uses. Event runoff and soil loss in forest, shrub and grass were measured in plots with lengths of 5, 9 and 13m in the Loess Plateau from 2008 to 2016. A total of 59 erosive rainfall events were recorded and classified into three rainfall regimes. Firstly, the results showed that the runoff coefficient was grass>shrub>forest, and soil loss was grass>forest>shrub, but the differences between forest and shrub in runoff and between grass and forest in soil loss did not reach significant levels. Secondly, rainfall regimes had an important effect on runoff and soil loss under different land uses. The lowest runoff coefficients and the highest soil loss in regime 2 were found in shrub and forest land, respectively, which differed from that of regime 1. In total, rainfall regime 1 had the highest runoff coefficient of 0.84–2.06%, followed by regime 3 with 0.33–0.88% and regime 2 with 0.04–0.06%. Soil loss in forest and grass land had a different order of regime 3>regime 1>regime 2. Thirdly, both the runoff coefficient and soil loss decreased with increasing plot length, while the effect of slope length on runoff/soil loss were influenced by land use type and rainfall regimes.


Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2299 ◽  
Author(s):  
Demesew A. Mhiret ◽  
Dessalegn C. Dagnew ◽  
Tilashwork C. Alemie ◽  
Christian D. Guzman ◽  
Seifu A. Tilahun ◽  
...  

The Ethiopian highlands suffer from severe land degradation, including erosion. In response, the Ethiopian government has implemented soil and water conservation practices (SWCPs). At the same time, due to its economic value, the acreage of eucalyptus has expanded, with croplands and pastures converted to eucalyptus plantations. The impact of these changes on soil loss has not been investigated experimentally. The objective of this study, therefore, is to examine the impacts of these changes on stream discharge and sediment load in a sub-humid watershed. The study covers a nine-year period that included installation of SWCPs, a three-fold increase from 1.5 ha in 2010 to 5 ha in 2018 in eucalyptus, and the upgrading of an unpaved to the paved road. Precipitation, runoff, and sediment concentration were monitored by installing weirs at the outlets of the main and four nested watersheds. A total of 867 storm events were collected in the nine years. Runoff and sediment concentration decreased by more than half in nine years. In the main watershed W5, we estimated that evapotranspiration by eucalyptus during the dry phase (November to May) increased approximately from 30 mm a−1 in 2010 to 100 mm a−1 in 2018. In watershed W3 it increased from 2 mm a−1 to 400 mm a−1, requiring more rainfall before saturation excess runoff began in the rain phase. The reduction in runoff led to a decreased sediment load from 70 Mg ha−1 a−1 in 2010 to 2.8 Mg ha−1 a−1 in 2018, though the reduction in discharge may have negative impacts on ecology and downstream water resources. SWCPs became sediment-filled and minimally effective by 2018. This indicates that these techniques are either inappropriate for this sub-humid watershed or require improved design and maintenance.


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