Estimating soil erosion in sub-Saharan Africa based on landscape similarity mapping and using the revised universal soil loss equation (RUSLE)

Tamene, Lulseged; Le, Quang Bao

doi:10.1007/s10705-015-9674-9

Cited by 72 publications

(55 citation statements)

References 39 publications

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“…Results of study are also in agreement with Tamene & Le (2015) findings on soil erosion in sub-Saharan Africa, these researchers reported that soil loss ranged from 25-75t/ha/year. However the results are far less than the results obtained by Karamage et al (2016) who observed the average soil loss of 250 t/ha/year in his study on extent of cropland and related soil erosion risk in Rwanda and 490 t/ha/year in his study of usle-based assessment of soil erosion by water in the Nyabarongo River Catchment, Rwanda.…”

Section: Discussionsupporting

confidence: 90%

Estimation of soil erosion risk, its valuation and economic implications for agricultural production in western part of Rwanda

Kabirigi¹,

Mugambi²,

Musana³

et al. 2017

JEBAS

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Multifunctional soil conservation strategies have the capacity to control soil erosion as well as increase its quality, thus leading to sustained yields as long as planners have knowledge on the severity of soil loss. A comprehensive methodology that integrates Revised Universal Soil Loss Equation (RUSLE) model and Geographic Information System (GIS) techniques was adopted to determine the soil erosion vulnerability within Katabuvuga, Nyamyumba and Mukamira watersheds in western part of Rwanda, with the aim of supporting planning of land and water management interventions. The dominant slop class in all watershed was 16-40% covering 50% in Katabuvuga watershed, 43% in Mukamira watershed and 70.6% in Nyamyumba watershed. High erosion risk was recorded in Mukamira (72 %) and it was followed by Nyamyumba (46 %). The average soil loss in selected watersheds was 32t/ha/year. Among the various studied watershed, highest average loss was reported in Nyamyumba watershed (37t/ha/year) while the lowest average was in Mukamira watershed (28t/ha/year). Soil loss was higher in cropland and lower in settlement. The average loss of nutrients was 1705 kg/ha/year of carbon, 155 kg/ha/year of nitrogen, 3 kg/ha/year of phosphurus and 111 kg/ha/year of potassium, the highest nutrient loss occurred in cropland. Based on the cost of NPK the average value of N lost per ha per year is 167507 Rwandan Francs (Rwf) while the value of P and K loss per ha per year is 3309 Rwf and 120189 Rwf respectively.

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Section: Discussionsupporting

confidence: 90%

Estimation of soil erosion risk, its valuation and economic implications for agricultural production in western part of Rwanda

Kabirigi¹,

Mugambi²,

Musana³

et al. 2017

JEBAS

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“…The mean estimates of 39.2 t ha −1 y −1 of soil eroded in 2015 ( Figure 6b) and 41.4 t ha −1 y −1 from Buberuka highlands AEZ (Table A1) are in accordance with the work of Kagabo et al [29], Kabirigi et al [36] and Karamage et al [37], but far less from the results reported by Karamage et al [9,26] ( Table 5). In addition, our findings are relatively comparable with a recent study conducted over the entire East Africa region with a mean soil loss of 34.2 t ha −1 y −1 for Rwanda [83], and in line with mean soil erosion rates ranging between 35 t ha −1 y −1 and 75 t ha −1 y −1 predicted in Sub-Saharan Africa [84]. Comparing the results of Karamage et al [9,26] (Table 4) with the findings of this study and other studies carried out in Rwanda and in the region, suggests that their results may be overestimates, an issue previously highlighted by Kabirigi et al [36].…”

Section: Perspective Of Soil Erosion By Water In Rwandasupporting

confidence: 91%

Land Use Change Impacts on Water Erosion in Rwanda

Nambajimana

Zhou

et al. 2019

Sustainability

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Rwanda has experienced accelerated soil erosion as a result of unsustainable human activities and changes in land use. Therefore, this study aimed at applying the RUSLE (Revised Universal Soil Loss Equation) model using GIS (Geographical Information System) and remote sensing to assess water erosion in Rwanda, focusing on the erosion-prone lands for the time span 2000 to 2015. The estimated mean annual soil losses were 48.6 t ha −1 y −1 and 39.2 t ha −1 y −1 in 2000 and 2015, respectively, resulting in total nationwide losses of approximately 110 and 89 million tons. Over the 15 years, 34.6% of the total area of evaluated LULC (land use/land cover) types have undergone changes. The highest mean soil loss of 91.6 t ha −1 y −1 occurred in the area changing from grassland to forestland (0.5%) while a mean soil loss of 10.0 t ha −1 y −1 was observed for grassland converting to cropland (4.4%). An attempt has been made to identify the embedded driving forces of soil erosion in Rwanda. As a result, we found that mean soil loss for Rwanda's districts in 2015 was significantly correlated with poverty (r = 0.45, p = 0.013), increased use of chemical fertilizers (r = 0.77, p = 0.005), and especially was related to extreme poverty (r = 0.77, p = 0.000). The soil conservation scenario analysis for Rwanda's cropland in 2015 revealed that terracing could reduce the soil loss by 24.8% (from 14.6 t ha −1 y −1 to 11.7 t ha −1 y −1 ). Most importantly, the study suggests that (1) terracing integrated with mulching and cover crops could effectively control water erosion while ameliorating soil quality and fertility, and (2) reforestation schemes targeting the rapid-growing tree species are therefore recommended as an important feature for erosion control in the study area.

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“…In most of Sub-Saharan Africa, more than 50% of the population heavily relies on local agriculture for food [3], where poor land management usually leads to extreme soil erosion [4]. Today, soil erosion is the major cause of land degradation in Sub-Saharan Africa with serious impacts on agricultural productivity [5]. Numerous studies have highlighted that land conversion to agricultural land use stands as a catalyst for accelerated soil erosion rates [6][7][8][9][10]; and if these agriculture-related erosion rates remain far beyond the rates of soil production, the global society will eventually be compelled to either adopt agricultural methods that sustain the soil or face increasing competition over a shrinking agricultural land base [6].…”

Section: Introductionmentioning

confidence: 99%

Extent of Cropland and Related Soil Erosion Risk in Rwanda

et al. 2016

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Land conversion to cropland is one of the major causes of severe soil erosion in Africa. This study assesses the current cropland extent and the related soil erosion risk in Rwanda, a country that experienced the most rapid population growth and cropland expansion in Africa over the last decade. The land cover land use (LCLU) map of Rwanda in 2015 was developed using Landsat-8 imagery. Based on the obtained LCLU map and the spatial datasets of precipitation, soil properties and elevation, the soil erosion rate of Rwanda was assessed at 30-m spatial resolution, using the Revised Universal Soil Loss Equation (RUSLE) model. According to the results, the mean soil erosion rate was 250 t¨ha´1¨a´1 over the entire country, with a total soil loss rate of approximately 595 million tons per year. The mean soil erosion rate over cropland, which occupied 56% of the national land area, was estimated at 421 t¨ha´1¨a´1 and was responsible for about 95% of the national soil loss. About 24% of the croplands in Rwanda had a soil erosion rate larger than 300 t¨ha´1¨a´1, indicating their unsuitability for cultivation. With a mean soil erosion rate of 1642 t¨ha´1¨a´1, these unsuitable croplands were responsible for 90% of the national soil loss. Most of the unsuitable croplands are distributed in the Congo Nile Ridge, Volcanic Range mountain areas in the west and the Buberuka highlands in the north, regions characterized by steep slopes (>30%) and strong rainfall. Soil conservation practices, such as the terracing cultivation method, are paramount to preserve the soil. According to our assessment, terracing alone could reduce the mean cropland soil erosion rate and the national soil loss by 79% and 75%, respectively. After terracing, only a small proportion of 7.6% of the current croplands would still be exposed to extreme soil erosion with a rate >300 t¨ha´1¨a´1. These irremediable cropland areas should be returned to mountain forest to foster environmental sustainability or further sustainable alternative erosion control techniques may be applied, such as applying Vetiver Eco-engineering Technology due to its economical soil erosion control and stabilization of steep slopes and the construction of erosion control dams to absorb and break down excess runoff from unusually intense storms in various parts of the watersheds.

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Estimating soil erosion in sub-Saharan Africa based on landscape similarity mapping and using the revised universal soil loss equation (RUSLE)

Cited by 72 publications

References 39 publications

Estimation of soil erosion risk, its valuation and economic implications for agricultural production in western part of Rwanda

Estimation of soil erosion risk, its valuation and economic implications for agricultural production in western part of Rwanda

Land Use Change Impacts on Water Erosion in Rwanda

Extent of Cropland and Related Soil Erosion Risk in Rwanda

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