Harmonisation of the soil map of Africa at the continental scale

Dewitte, Olivier; Jones, Arwyn; Spaargaren, Otto; Breuning‐Madsen, Henrik; Brossard, Michel; Dampha, A.; Deckers, Jozef; Gallali, Tahar; Hallett, Stephen R; Jones, Robert J. A.; Kilasara, Method; Roux, Pieter Le; Michéli, Erika; Montanarella, Luca; Thiombiano, L.; Ranst, Éric Van; Yemefack, Martin; Zougmoré, Robert B.

doi:10.1016/j.geoderma.2013.07.007

Cited by 171 publications

(107 citation statements)

References 16 publications

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“…The restricted available quantity of suspended river particulates did not allow us to determine their clay mineralogy. However, information on soil types was provided for each studied river subbasins using the soil atlas of Africa (Dewitte et al, 2013). All data about lithology and soil types are reported in Table 5.…”

Section: Rivers Of Northern Irelandmentioning

confidence: 99%

The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology

Bayon

Delvigne

Ponzevera

et al. 2018

Geochimica et Cosmochimica Acta

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The d 30 Si stable isotopic composition of silicon in soils and fine-grained sediments can provide insights into weathering processes on continents, with important implications on the Si budget of modern and past oceans. To further constrain the factors controlling the distribution of Si isotopes in sediments, we have analysed a large number (n = 50) of separate size-fractions of sediments and suspended particulate materials collected near the mouth of rivers worldwide. This includes some of the world's largest rivers (e.g. Amazon, Congo, Mackenzie, Mississippi, Murray-Darling, Nile, Yangtze) and rivers from the case study areas of the Congo River Basin and Northern Ireland. Silt-size fractions exhibit a mean Si isotopic composition (d 30 Si = À0.21 ± 0.19‰; 2 s.d.) similar to that previously inferred for the upper continental crust. In contrast, clay-size fractions display a much larger range of d 30 Si values from À0.11‰ to À2.16‰, which yield a global d 30 Si clay of À0.57 ± 0.60‰ (2 s.d.) representative of the mean composition of the average weathered continental crust. Overall, these new data show that the Si isotopic signature transported by river clays is controlled by the degree of chemical weathering, as inferred from strong relationships with Al/Si ratios. At a global scale, the clay-bound Si isotopic composition of the world's largest river systems demonstrates a link with climate, defining a general correlation with mean annual temperature (MAT) in corresponding drainage basins. While the distribution of Si isotopes in river sediments also appears to be influenced by the tectonic setting, lithological effects and sediment recycling from former sedimentary cycles, our results pave the way for their use as paleo-weathering and paleo-climate proxies in the sedimentary record.

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Section: Rivers Of Northern Irelandmentioning

confidence: 99%

The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology

Bayon

Delvigne

Ponzevera

et al. 2018

Geochimica et Cosmochimica Acta

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“…Sub-Saharan Africa is an enormous region of 24.6 million km 2 , with a huge range of soil and land management types [24]. The predominant soils (Table 1) are Arenosols (21.5%), Cambisols (10.8%), and Ferralsols (10.4%), and Leptosols (17.5%).…”

Section: Spatial Scalesmentioning

confidence: 99%

The State of Soil Degradation in Sub-Saharan Africa: Baselines, Trajectories, and Solutions

et al. 2015

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Abstract:The primary cause of soil degradation in sub-Saharan Africa (SSA) is expansion and intensification of agriculture in efforts to feed its growing population. Effective solutions will support resilient systems, and must cut across agricultural, environmental, and socioeconomic objectives. While many studies compare and contrast the effects of different management practices on soil properties, soil degradation can only be evaluated within a specific temporal and spatial context using multiple indicators. The extent and rate of soil degradation in SSA is still under debate as there are no reliable data, just gross estimates. Nevertheless, certain soils are losing their ability to provide food and essential ecosystem services, and we know that soil fertility depletion is the primary cause. We synthesize data from studies that examined degradation in SSA at broad spatial and temporal scales and quantified multiple soil degradation indicators, and we found clear indications of degradation across multiple indicators. However, different indicators have different trajectories-pH and cation exchange capacity tend to decline linearly, and soil organic carbon and yields non-linearly. Future research should focus on how soil degradation in SSA leads to changes in ecosystem services, and how to manage these soils now and in the future. OPEN ACCESS

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“…01 on the most stable soils (El Garouani et al,2008). Our results are obtained by using soil analysis of 54 soil samplesand aggregate data of soil analysis provided by FAO in their harmonized database of the World Soil (Dewitte et al,2013) and Sheet information of OMAFRA based on USLE (Stone and Hilborn, 2012).…”

Section: Rainfall Erosivity Factor Rmentioning

confidence: 99%

Modelling Reservoir Sedimentation at Bin El Ouidane Dam, Morocco

Sabri¹,

Boukdir²,

Maslouhi³

et al. 2018

AGR

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This study was conducted in the Oued El Abid watershed upstream of the Bin El Ouidane dam, in Tadla-Azilal province (Morocco) to quantify the dam siltation rates. To assess the annual soil erosion and the sediment yield the universal soil loss equation (USLE) was used. A geographic information system (GIS) was used to generate and integrate maps of the USLE factors. A spatial distribution of soil erosion in the Oued El Abid watershed was obtained. The soil erosion was determined for each rural commune in order to identify the soil erosion hotspot and estimate the amount of soil that has been transported downstream (Bin El Ouidane Dam). Soil erosion ranged from very limited values for flat and well covered areas to over 2100 t /ha/y in mountainous areas with sparse vegetation. The total annual soil loss within the watershed is estimated at 19. 6 million tons per year. An equation of sediment delivery ratio (SDR) based on river gradient was calculated. It was found that the value of SDR at the outlet of the watershed Oued El Abid was 0. 65 with a sediment yield of 12. 74 million tons per year which affect the durability of the dam.

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Harmonisation of the soil map of Africa at the continental scale

Cited by 171 publications

References 16 publications

The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology

The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology

The State of Soil Degradation in Sub-Saharan Africa: Baselines, Trajectories, and Solutions

Modelling Reservoir Sedimentation at Bin El Ouidane Dam, Morocco

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