| 1. |
- Ardö, Jonas, et al.
(författare)
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Assessment of soil organic carbon in semi-arid Sudan using GIS and the CENTURY model
- 2003
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Ingår i: Journal of Arid Environments. - : Elsevier BV. - 1095-922X .- 0140-1963. ; 54:4, s. 633-651
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Tidskriftsartikel (refereegranskat)abstract
- Using the UNFCCC as a basis, and the objectives of estimating soil organic carbon (SOC) changes during the period 1900-2100, a spatially explicit database of climate, land cover and soil texture was compiled for a 262,000 km(2) region in semi-arid Sudan. The area is characterized by low input cultivation of millet, sorghum and sesame combined with livestock grazing. By integrating the database with the CENTURY ecosystem model, we were able to estimate historical, current and future pools of SOC as a function of land management and climate. The SOC (upper 20 cm) decrease from 1900 to 2000 was estimated to be 6.8 Mt and the maximum potential carbon sink (SOC increase) for the period 2000 to 2 100 was estimated to be 17 Mt. Cropland and grassland lost 293 and 152t SOC km(-2) respectively whereas the savannahs gained 76t SOC km(-2) from 1900 to 2000. The SOC sequestration scenario simulated during 2000-2100 recovered 94, 84 and 75 tkm(-2) for cropland, grassland and savannah respectively. In addition to climate and soils, cropping intensity, fallow periods, fire frequency and grazing intensity also influence cropland SOC variation. Grassland and savannah SOC variations depend on grazing intensity and fire return interval. Land management may affect future amounts of SOC in semi-arid areas thereby turning them from sources into sinks of carbon. SOC estimates were reasonably consistent with measurements (r(2) = 0.70, n = 13).
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| 2. |
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| 3. |
- Ardö, Jonas, et al.
(författare)
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Soil carbon sequestration in traditional farming in Sudanese dry lands
- 2004
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Ingår i: Environmental Management. - : Springer Science and Business Media LLC. - 0364-152X .- 1432-1009. ; 33, s. 318-329
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Tidskriftsartikel (refereegranskat)abstract
- Do altered land management practices offer possibilities to sequester carbon in the soil and thereby mitigate increasing atmospheric CO2 as well as improve local soil fertility? This study investigates the impact of fallow periods on soil organic carbon in semiarid subsistence agroecosystems on sandy and poor soils in Kordofan, Sudan. The area is characterized by low-input cultivation of millet and sorghum in combination with livestock grazing. Recently, cultivation intensity has increased and the fallow periods have been shortened. Soil carbon contents were assessed for sites that have been under various cultivation intensities, ranging from 30 years of fallow to 30 years of continuous cultivation. Soil organic carbon showed a significant negative relationship with cultivation intensity. Measurements indicate a mean increase of approximately 4 g soil organic carbon (SOC) per square meter per year during fallow periods. The possibilities of increasing soil organic carbon by land management were also estimated through simulations using the Century model. Modeling suggested that reverting an intensely cropped millet site to permanent grassland would sequester approximately 1-2 g SOC/m(2)/yr, with higher rates during the early part of the period. Continuous intense cultivation could decrease the currently low soil carbon levels even further. These results indicate that altered land management could contribute to transforming degraded semiarid agroecosystems from a source to a weak sink for atmospheric CO2. Possible data improvements and uncertainties are discussed.
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| 4. |
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| 5. |
- Arneth, Almut, et al.
(författare)
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Restoring Degraded Lands
- 2021
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Ingår i: Annual Review of Environment and Resources. - : Annual Reviews. - 1543-5938 .- 1545-2050. ; 46, s. 569-599
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Forskningsöversikt (refereegranskat)abstract
- Land degradation continues to be an enormous challenge to human societies, reducing food security, emitting greenhouse gases and aerosols, driving the loss of biodiversity, polluting water, and undermining a wide range of ecosystem services beyond food supply and water and climate regulation. Climate change will exacerbate several degradation processes. Investment in diverse restoration efforts, including sustainable agricultural and forest land management, as well as land set aside for conservation wherever possible, will generate co-benefits for climate change mitigation and adaptation and morebroadly for human and societal well-being and the economy. This review highlights the magnitude of the degradation problem and some of the key challenges for ecological restoration. There are biophysical as well as societal limits to restoration. Better integrating policies to jointly address poverty, land degradation, and greenhouse gas emissions and removals is fundamental to reducing many existing barriers and contributing to climate-resilient sustainable development.
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| 6. |
- Buramuge, Victorino Américo, et al.
(författare)
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Exploring Spatial Distributions of Land Use and Land Cover Change in Fire-Affected Areas of Miombo Woodlands of the Beira Corridor, Central Mozambique
- 2023
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Ingår i: Fire. - : MDPI AG. - 2571-6255. ; 6:2
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Tidskriftsartikel (refereegranskat)abstract
- Miombo woodlands (MW) are increasingly experiencing widespread land use and land cover change (LULCC). This study explores the influence of fire, agriculture, and slope variability on LULCC in the miombo of the Beira Corridor. Land use and land cover data were derived from three Landsat images for 2001, 2008, and 2018. Slope attributes were derived from the Shuttle Radar Topography Mission (SRTM). Monthly burned data of Moderate-Resolution Imaging Spectroradiometer (MODIS) were used to map fire frequency. The derived data were then used to investigate the relationship between LULCC and fire, agriculture, and slope, based on geographically weighted regression (GWR). In addition, the relationship between LULCC and slope was assessed. Our findings indicate that fire frequency, agriculture, and slope were significantly spatially non-stationary. We found that LULCC was negatively correlated with agriculture in open miombo, but positively correlated in dense miombo. A positive relationship between LULCC and fire was found for dense and open miombo. Changes in agriculture, dense miombo, and open miombo increased towards high slopes. The study improves the understanding of the spatial effect of LULCC drivers. The development and implementation of effective fire management actions is required to promote sustainable forest management and preservation of critical ecosystem services.
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| 7. |
- Dent, David, et al.
(författare)
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Land
- 2007
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Ingår i: Global Environmental Outlook 4. - 9789280728361 ; , s. 81-114
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 8. |
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| 9. |
- Eklundh, Lars, et al.
(författare)
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Vegetation index trends for the African Sahel 1982-1999
- 2003
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Ingår i: Geophysical Research Letters. - 1944-8007. ; 30:8, s. 1430-1433
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Tidskriftsartikel (refereegranskat)abstract
- [1] Pathfinder AVHRR NDVI data have been analyzed for the African Sahel to study recent trends in vegetation greenness. A strong increase in seasonal NDVI was observed over large areas in the Sahel during the period 1982-1999. The increase is interpreted as a vegetation recovery from the drought periods of the 1980's. Although strong shifts in satellite overpass times have led to shifting solar zenith angles (SZA) over the time period, only minimal influence of SZA's on the Pathfinder NDVI was found in our data. A preliminary analysis of rainfall data indicates increasing rainfall during the period. The observed trends may have important implications to the Sahel including changes to the water cycle, energy exchange and carbon storage.
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| 10. |
- Elmqvist, Bodil, et al.
(författare)
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A traditional agroforestry system under threat: an analysis of the gum arabic market and cultivation in the Sudan
- 2005
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Ingår i: Agroforestry Systems. - : Springer Science and Business Media LLC. - 1572-9680 .- 0167-4366. ; 64:3, s. 211-218
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Tidskriftsartikel (refereegranskat)abstract
- The main aim of this study is to review the environmental and socioeconomic sustainability of the gum arabic farming system in central Sudan. A further aim is to analyse some of the main factors influencing production in recent decades in order to understand the future trade potential and consequently the smallholder livelihood. The study shows that end-user imports of gum arabic have increased during recent decades. Gum arabic is mainly for uses such as soft drinks, confectionary, and pharmaceuticals. However, even with this increased demand the production in Sudan, the main country of production, is declining. The producers, mainly smallholders, suger from fluctuating prices. If the gum arabic farming system should be able to provide the environmental benefits of improved soil fertility and the socioeconomic benefits of risk spreading and dry season income opportunities, the prices paid to smallholders must be stabilized at a fair level, otherwise a shift to other crops or practices might take place.
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