scholarly journals Estimating soil erosion risk and evaluating erosion control measures for soil conservation planning at Koga watershed in the highlands of Ethiopia

Solid Earth ◽  
2017 ◽  
Vol 8 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Tegegne Molla ◽  
Biniam Sisheber

Abstract. Soil erosion is one of the major factors affecting sustainability of agricultural production in Ethiopia. The objective of this paper is to estimate soil erosion using the universal soil loss equation (RUSLE) model and to evaluate soil conservation practices in a data-scarce watershed region. For this purpose, soil data, rainfall, erosion control practices, satellite images and topographic maps were collected to determine the RUSLE factors. In addition, measurements of randomly selected soil and water conservation structures were done at three sub-watersheds (Asanat, Debreyakob and Rim). This study was conducted in Koga watershed at upper part of the Blue Nile basin which is affected by high soil erosion rates. The area is characterized by undulating topography caused by intensive agricultural practices with poor soil conservation practices. The soil loss rates were determined and conservation strategies have been evaluated under different slope classes and land uses. The results showed that the watershed is affected by high soil erosion rates (on average 42 t ha−1 yr−1), greater than the maximum tolerable soil loss (18 t ha−1 yr−1). The highest soil loss (456 t ha−1 yr−1) estimated from the upper watershed occurred on cultivated lands of steep slopes. As a result, soil erosion is mainly aggravated by land-use conflicts and topographic factors and the rugged topographic land forms of the area. The study also demonstrated that the contribution of existing soil conservation structures to erosion control is very small due to incorrect design and poor management. About 35 % out of the existing structures can reduce soil loss significantly since they were constructed correctly. Most of the existing structures were demolished due to the sediment overload, vulnerability to livestock damage and intense rainfall. Therefore, appropriate and standardized soil and water conservation measures for different erosion-prone land uses and land forms need to be implemented in Koga watershed.

2017 ◽  
Author(s):  
Kaisar

This study aims to (1) Predicting the actual erosion and erosion determine which allowed the various patterns of farming in the village Palatta Tapango District of Polewali Mandar, (2) Formulate soil and water conservation measures on each pattern farm. This researh was conducted in the village of the District Palatta Tapango Polewali Mandar. Data collected through direct observation of the research object in the field. The method used in predicting the amount of erosion is common soil loss equation (USLE method). The result showed that the amount of erosion that accurs in six patterns of farming is 42.76 tons per hectare per year. Based sixth farming patterns were obtained magnitude of the rate erosion on any bentukpola,namely (1)Gamal, banan, jackfruit, durian, Grass 17.86 tonnes per hectare per year, (2) Brown, of falm, Rambutan, Gamal, Litter 10.08 tons per hectare per year, (3) Sengon, Banana, Mango, Chocholate, Coffe, Bushes 4.70 tonnes per hectare per year, (4) Brown, Pinus, Litter 4.20 tonnes per hectare per year, (5) of palm, Brown, jackfruit, banana,Gamal, Litter 3.61 tonnes per hectare per year, and (6) Langsat, Durian, Brown, grass 2,31 tons per hectare per year. The amount of erosion that occurs in various patterns of faming still exceeds the amount of erosion is allowed. To that end, the necessary efforts to reduce the rate of erosion of soil conservation practices and land uses that provide protection or land cover better.


2020 ◽  
Vol 13 (3) ◽  
pp. 1117
Author(s):  
Julio Caetano Tomazoni ◽  
Ana Paula Vansan

Este trabalho tem como objetivo avaliar a erosão hídrica laminar do solo, por meio da Equação Universal de Perdas de Solos Revisada (RUSLE) na bacia hidrográfica do rio São José, localizada no município de Francisco Beltrão (PR).  A perda de solo média anual (A) foi determinada através da RUSLE para os anos 2000, 2005, 2009, 2015 e 2017 utilizando-se técnicas de geoprocessamento com o auxílio do software ArcGis 10.0. O fator erosividade da chuva (R) foi determinado utilizando-se dados pluviométricos correspondentes ao período de 1974 a 2016. O fator erodibilidade do solo (K) foi obtido através da análise de amostras de solo coletadas in loco. O fator topográfico (LS) foi estimado por meio dos dados altimétricos e hidrográficos da bacia. Os fatores de uso e manejo do solo (C) e de práticas conservacionistas do solo (P) foram determinados por meio da caracterização multitemporal do uso e ocupação do solo, através de imagens de satélite. O potencial natural de erosão (PNE) foi determinado pela multiplicação dos fatores R, K e LS.A estimativa de perda de solo (A) foi determinada pela multiplicação do PNE pelos fatores C e P.  Use of Geoprocessing Techniques to Study Laminar Water Erosion in Watershed of Southwest Paraná A B S T R A C TThe objective of this work is evaluate the soil erosion by the Universal Equation of Soil Losses Revised (RUSLE) in the São José river basin, located in the municipality of Francisco Beltrão (PR). The average annual soil loss (A) was determined through RUSLE for the years 2000, 2005, 2009, 2015 and 2017 using geoprocessing techniques with ArcGis 10.0 software. Rainfallerosivity (R) was determined using rainfall data from 1974 to 2016, being determined at 11521.26 11521,26 MJ.mm.ha-1.h-1.year-1. The soil erodibility factor (K) was obtained through the analysis of soil samples collected on the spot (0,03018 t.ha.h/ha.MJ.mm, 0,02771 t.ha.h/ha.MJ.mm e 0,02342 t.ha.h/ha.MJ.mm). The topographic factor (LS) was estimated by the altimetric and hydrographic data of the basin. Soil use and management (C) and soil conservation (P) were determined through multitemporal characterization of land use and occupation, using satellite images. The natural erosion potential (NEP) was determined by multiplying the R, K and LS factors, with more than half of the total area of the watershed with very strong PNE. The soil loss estimate (A) was determined by multiplying the NEP by factors C and P with predominance of the class called low (0 to 10 t/ha/year) denoting the reduction of erosion rates through factors C and P, helping to protect the soil from the erosion process.Key words: Soil Erosion; Watershed, Revised Universal Soil Loss Equation, Geoprocessing, Software.


Agropedology ◽  
2019 ◽  
Vol 28 (2) ◽  
Author(s):  
S. V. Shejale ◽  
◽  
S. B. Nandgude ◽  
S. S. Salunkhe ◽  
M. A. Phadtare ◽  
...  

Present research work was carried out on soil erosion and crop productivity loss in Palghar and Thane districts. The study also describes tolerable soil loss and relationship between top-soil loss and yield loss. The estimated average annual soil loss was 40.45 t ha-1yr-1 before adoption of the soil and water conservation measures (by USLE method) and estimated average tolerable soil loss was 9.36 t ha-1 yr-1, for Palghar district. Similarly, for Thane district the estimated average annual soil loss and tolerable soil loss were found to be 35.89 t ha-1 yr-1 and 9.61 t ha-1 yr-1, respectively for Thane district. The estimated average conservation practice factor (P) factors were obtained as 0.32 for Palghar district and 0.30 for Thane district to bring the soil loss below the tolerable limit. After adoption of soil and water conservation measures, the estimated soil loss were 9.02 t ha-1 yr-1 and 9.38 t ha-1 yr-1 for Palghar and Thane districts, respectively.


2020 ◽  
Vol 12 (9) ◽  
pp. 1365 ◽  
Author(s):  
Panos Panagos ◽  
Cristiano Ballabio ◽  
Jean Poesen ◽  
Emanuele Lugato ◽  
Simone Scarpa ◽  
...  

Soil erosion is one of the eight threats in the Soil Thematic Strategy, the main policy instrument dedicated to soil protection in the European Union (EU). During the last decade, soil erosion indicators have been included in monitoring the performance of the Common Agricultural Policy (CAP) and the progress towards the Sustainable Development Goals (SDGs). This study comes five years after the assessment of soil loss by water erosion in the EU [Environmental science & policy 54, 438–447 (2015)], where a soil erosion modelling baseline for 2010 was developed. Here, we present an update of the EU assessment of soil loss by water erosion for the year 2016. The estimated long-term average erosion rate decreased by 0.4% between 2010 and 2016. This small decrease of soil loss was due to a limited increase of applied soil conservation practices and land cover change observed at the EU level. The modelling results suggest that, currently, ca. 25% of the EU land has erosion rates higher than the recommended sustainable threshold (2 t ha−1 yr−1) and more than 6% of agricultural lands suffer from severe erosion (11 t ha−1 yr−1). The results suggest that a more incisive set of measures of soil conservation is needed to mitigate soil erosion across the EU. However, targeted measures are recommendable at regional and national level as soil erosion trends are diverse between countries which show heterogeneous application of conservation practices.


Water SA ◽  
2019 ◽  
Vol 45 (1 January) ◽  
Author(s):  
Daniel Otim ◽  
Jeff Smithers ◽  
Aidan Senzanje ◽  
Rianto Van Antwerpen

This paper contains a critical review of the norms employed in the design of soil and water conservation structures in the South African sugar industry and highlights research needs in order to update them. Sugarcane in South Africa is grown on wide-ranging soils, sometimes in non-ideal climates and on steep topographies where soils are vulnerable to erosion. A consequence of unsustainable soil loss is reduction in field production capacity. Sugarcane fields are protected against erosion through, inter alia, the use of engineered waterways, contour banks and spill-over roads. The South African Sugarcane Research Institute (SASRI), previously known as the South African Sugar Experiment Station (SASEX), developed a nomograph to easily compute the maximum width of field panels based on soil type, tillage method, replant method, surface structures to control runoff, surface cover and slope. This was followed by guidelines and norms for the design of soil and water conservation structures. However, the nomograph was developed based on an acceptable soil loss of 20 t·ha−1·yr−1, yet soil formation rates in South Africa range between 0.25 and 0.38 t·ha−1·yr−1. Comparisons between design norms in the National Soil Conservation Manual and norms used in the sugar industry clearly show discrepancies that need to be investigated. The design of soil conservation structures includes the design of both contour bank spacing and hydraulic capacity. The sustainable soil loss method is recommended in the design of contour spacing and it determines contour spacing based on evaluation of site-specific sheet and rill erosion potential of the planned contour spacing while the hydraulic design employs Manning’s equation. Considering that increases in both design rainfall and design floods are anticipated in South Africa, it is necessary to incorporate these projections in the design of soil and water conservation structures. Many soil loss models exist, of which empirical models are the most robust and provide stable performances. The majority of empirical models are lumped models which estimate average annual soil loss. The Modified Universal Soil Loss Equation (MUSLE) estimates event-based erosion and, given that the majority of soil erosion occurs during a few extreme events annually, the design norms should be updated using the MUSLE.


2020 ◽  
Vol 12 (3) ◽  
pp. 934 ◽  
Author(s):  
Mengfan Cai ◽  
Chunjiang An ◽  
Christophe Guy ◽  
Chen Lu

Soil and water conservation practices (SWCPs) are widely used to control soil and water loss. Quantifying the effect of SWCPs and climate change on soil and water erosion is important for regional environmental management. In this study, the Soil Conservation Service Curve Number (SCS-CN) and the Modified Universal Soil Loss Equation (MUSLE) were employed to investigate the patterns of surface runoff and soil erosion with different SWCPs in the hilly region on the Loess Plateau of China. The impact of climate change under RCP4.5 and RCP8.5 emission scenarios was considered from 2020 to 2050. Surface runoff grew with the increased rainfall and rainfall erosivity, while soil erosion presented large variations between years due to uneven distribution of rainfall and rainfall erosivity under two scenarios. Different SWCPs significantly reduced surface soil and water loss. Compared with bare slopes, the reduction rates were 15–40% for surface runoff and 35–67% for soil erosion under RCP4.5 and RCP8.5 emission scenarios, respectively. The combination of shrub and horizontal terracing was recommended due to its low water cost for sediment control among seven SWCPs.


1993 ◽  
Vol 73 (4) ◽  
pp. 515-526 ◽  
Author(s):  
Y. Z. Cao ◽  
D. R. Coote ◽  
C. Wang ◽  
M. C. Nolin

137Cs in the soil was used to estimate soil erosion at two National Soil Conservation Program benchmark sites in the province of Quebec (sites 15-QU and 16-QU). The 137Cs baseline in an uneroded forest area was approximately 3100 Bq m−2. The 137Cs content at site 15-QU ranged from 1072 Bq m−2 to 6389 Bq m−2, while at site 16-QU it ranged from 663 Bq m−2 to 5444 Bq m−2. Computed net erosion over the past 30 yr at site 15-QU varied from a loss of 9.65 kg m−2 yr−1 to a gain of 10.88 kg m−2 yr−1 and at site 16-QU from a loss of 6.38 kg m−2 yr−1 to a gain of 1.73 kg m−2 yr−1. The average net erosion rates were 2.43 kg m−2 yr−1 at site 15-QU and 1.29 kg m−2 yr−1 at site 16-QU. Soil samples collected on a grid pattern indicated that 90% and 83% of the area at sites 15-QU and 16-QU, respectively, was subjected to net soil loss. A comparison of total 137Cs movement from eroded areas to depositional areas showed that 24.2% of 137Cs was lost from site 15-QU, while about 17.6% of 137Cs was lost from site 16-QU. Mapping of 137Cs content and calculated soil loss and deposition showed that soil erosion was closely related to topography.Under similar slope conditions, the soil erosion rates were 27–68% higher at site 15-QU than at site 16-QU. Higher tillage frequency and use of silage corn were the suggested reasons for the higher soil erosion rates at site 15-QU compared with site 16-QU, which had been used for hay and small grains. Key words: 137Cs, erosion, deposition, soil conservation


Soil Research ◽  
2012 ◽  
Vol 50 (8) ◽  
pp. 645 ◽  
Author(s):  
Rody Nigel ◽  
Soonil D. D. V. Rughooputh

Soil erosion by water is one of the most important natural resources management problems in the world. The damages it causes on-site are soil loss, breakdown of soil structure, and decline in organic matter content, nutrient content, fertility, and infiltration rate. Lands with the highest erosion risk on Mauritius Island are crop cultivations (sugarcane, tea, vegetables) on erosion-susceptible terrain (slopes >20% coupled with highly erodible soils). The locations of such lands on Mauritius were mapped during previous, qualitatively based regional-scale erosion studies. In order to propose soil conservation strategies, there is a need to apply a more quantitative approach to supplement the previous, qualitatively based studies. This paper reports an application of the Revised Universal Soil Loss Equation (RUSLE) within a geographical information system in order to estimate soil loss on the island, and particularly for the high-erosion areas. Results show that total soil loss on the island is estimated at 298 259 t year–1, with soil loss from high-erosion areas summing 84 780 t year–1 (28% of total soil loss). If all of the high-erosion areas were afforested, their soil loss would be reduced to 10 264 t year–1, i.e. a reduction of 88% for the high-erosion areas and a reduction of 25% for the island. This study thus calls for soil and water conservation programs directed to these erosion-prone areas before the land degradation and environmental damage they are causing become irreversible. The methodological approach used in this work to quantitatively estimate soil loss from erosion-prone areas can be adopted in other countries as the basis for a nationwide erosion assessment in order to better inform environmental policy needs for soil and water conservation.


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