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1.
  • Öborn, Ingrid, et al. (författare)
  • Restoring rangelands for nutrition and health for humans and livestock
  • 2023
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Drylands cover 40% of the global land area and host 2 billion people, of which 90% live in low- or middleincome countries. Drylands often face severe land degradation, low agricultural productivity, rapid population growth, widespread poverty, and poor health. Governance structures and institutions are often eroded. Livestock-based livelihoods, largely depending on seasonal migration are common. Pastoralist communities and their land are highly vulnerable to climate shocks, while there are also changes in land tenure, insecurity/conflicts and rapid infrastructure development. Drylands Transform is an interdisciplinary research project revolving around the UN Sustainable Development Goals (SDGs). The project aim is to contribute new knowledge to a transformative change and sustainable development of drylands in East Africa to help escape the ongoing negative spiral of land, livestock and livelihood degradation. We investigate the links between land health, livelihoods, human well-being, and land management and governance with several study sites along the Kenya-Uganda border. Through strong stakeholder engagement we will explore challenges and pathways towards a social-ecological transformation in these drylands. The entry point is the urgent need to identify and enhance synergies between food and nutrition security (SDG2), land and ecosystem health (SDG15) and governance and justice (SDG16) for sustainable dryland development, aiming to improve health and equity (SDGs 3 and 5), while minimizing trade-offs between agricultural productivity, natural resources management and climate change. We are using innovative field research approaches focusing on livelihood improvement through rangeland (grazing areas) restoration and governance interventions. We will present results from the initial work to assess land health using the Land Degradation Surveillance Framework and explore the links with human health and well-being through household survey data. We will also show how we will co-develop sustainable dryland management options (e.g., field experiments with fodder grasses and shrubs) with local communities and set-up knowledge sharing hubs.
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2.
  • Bargues Tobella, Aida, et al. (författare)
  • Strategies trees use to overcome seasonal water limitation in an agroforestry system in semiarid West Africa
  • 2017
  • Ingår i: Ecohydrology. - : Wiley. - 1936-0584 .- 1936-0592. ; 10
  • Tidskriftsartikel (refereegranskat)abstract
    • Agroforestry parklands, in which annual crops are grown under scattered mature trees, constitute the most prevalent farming system in semiarid West Africa, covering vast areas of land. The most dominant tree species in these systems is Vitellaria paradoxa, an indigenous tree to West Africa. Despite the importance of this tree in the region, no study to our knowledge has examined its sources and patterns of water uptake. In this study, we used oxygen stable isotopes at natural abundance levels to investigate water sources used by V. paradoxa both in the dry and wet season in an agroforestry parkland in Burkina Faso. We found that during the wet season soil moisture was highest near the soil surface (< 10 cm depth), yet during this time V. paradoxa preferentially accessed water from slightly deeper soil depths, obtaining ca. 90% of its water from 10 to 50 cm depth. In contrast, soil moisture in the upper soil layers was significantly lower during the dry season and as a result V. paradoxa shifted to deeper water sources, obtaining ca. 30% of its water from groundwater and ca. 50% from 30 to 600 cm depth. We also found a negative relationship between tree size and the contribution of groundwater during the dry season, whereas during the wet season V. paradoxa predominantly used water near the soil surface regardless of tree size. Knowledge about the sources and patterns of tree water uptake provides crucial information to better understand how trees influence the local water balance.
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3.
  • Bostedt, Göran, et al. (författare)
  • Adaptive pastoralists—Insights into local and regional patterns in livelihood adaptation choices among pastoralists in Kenya
  • 2023
  • Ingår i: Pastoralism. - : Springer Nature. - 2041-7136. ; 13:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Pastoralist adaptation strategies have to address multiple, overlapping, and often inter-related processes of socio-ecological change. The present study addresses the need for inter-regional comparative studies that account for different geographic, climate, and socio-economic contexts in order to understand how pastoralists adapt to changes in livelihood conditions. The paper uses data from a unique survey study of pastoralist households in four neighbouring counties in dryland Kenya. Taking our point of departure from an empirically based classification of the livelihood strategies available to pastoralists in the Horn of Africa, the survey offers novel insights into adaptation and fodder management strategies of pastoralist individuals and households. The results show that the use of migration as a strategy is more dependent on the ability to migrate than climate conditions. This is the case in localities where a substantial part of the land is subdivided, the population density is high, and where opportunities for migration are subsequently restricted. Diversification of livelihoods as a strategy is largely defined by opportunity. Intensification through active fodder management is mainly common in areas where there has been a proliferation of managed enclosures. Climate change will test the adaptive capacity of pastoralists in the studied region, and diversification and intensification strategies of both herd composition and livelihoods can be seen as strategies for increased climate resilience.
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4.
  • Bostedt, Göran, 1966-, et al. (författare)
  • Agroforestry Extension and Dietary Diversity : An Analysis of the Importance of Fruit and Vegetable Consumption in West Pokot, Kenya
  • 2016
  • Ingår i: Food Security. - : Springer Science and Business Media LLC. - 1876-4517 .- 1876-4525. ; 8:1, s. 271-284
  • Tidskriftsartikel (refereegranskat)abstract
    • Worldwide, the challenges of nomadic, pastoralist systems are causing their slow but steady disappearance in favour of sedentary agropastoralism. This paper draws upon an existing household data set from a survey collected and organized by the Swedish non-governmental organization (NGO) Vi Agroforestry, directed at a livestock-based, agro-pastoralist area in West Pokot County, western Kenya. The study focuses on the question of food diversity and malnutrition and the role of agroforestry extension services, i.e. knowledge spread, transfer and development. Our basic hypothesis is that certain fruit and vegetable related food groups are under-consumed in West Pokot, especially in the dryland areas. The results of the study shows that agroforestry, combined with advice through extension efforts can imply a transition path for pastoralists which involves improved dietary diversity, especially concerning food groups that include roots, tubers, fruits and leafy vegetables. From the results certain restrictions that hinder this transition become clear. An important but often overlooked factor is lack of information and knowledge as a determinant of household behavior in developing countries. NGOs such as Vi Agroforestry can play an important role in overcoming this restriction by providing extension services. Developing countries in general are not information-rich environments, a fact that is especially the case for poor citizens living in rural areas. The paper illustrates that careful attention to the information and knowledge available to households is necessary when designing development cooperation.
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5.
  • Bostedt, Göran, 1966-, et al. (författare)
  • Saving and borrowing behaviour among agropastoralists in West Pokot County, Kenya
  • 2021
  • Ingår i: Journal of International Development. - : John Wiley & Sons. - 0954-1748 .- 1099-1328. ; 33:6, s. 1043-1062
  • Tidskriftsartikel (refereegranskat)abstract
    • Financial inclusion is an important development impetus, where knowledge of saving and borrowing behaviour provides valuable insights. This study focuses on access to and use of financial services among agropastoralists in rural Kenya, using survey-based household data from 2007 and 2017. Surveys show that households with savings increased from about 57% to 71%—coinciding with increased access to financial training and growing use of informal group-based savings organizations. Share of households that had access to credit also increased during this period, from about 26% to 54%. Support to group-based savings organizations can stimulate financial inclusion among agropastoralists. 
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6.
  • Burian, Alfred, et al. (författare)
  • A community-based evaluation of population growth and agro-pastoralist resilience in Sub-Saharan drylands
  • 2019
  • Ingår i: Environmental Science and Policy. - : Elsevier BV. - 1462-9011 .- 1873-6416. ; 92, s. 323-330
  • Tidskriftsartikel (refereegranskat)abstract
    • Human population growth is considered together with climate warming as major driver of change in Sub-Saharan Africa. Research on the implications of increased population densities often utilises community knowledge but without incorporating the view of local stakeholders. In this study, we applied a community centred approach to assess direct and indirect consequences of population growth in drylands of north-western Kenya. Combined social, agricultural and geo-spatial analyses allowed us to identify major system transitions, determine their linkage to population growth and deduce consequences for local livelihoods and community resilience. Community-members reported positive and negative consequences of fourfold population growth since 1974 but evaluated its overall effect as clearly beneficial. This overall positive effect was based on both, positive developments and the successful mitigation of potential system stressors. First, food security was maintained despite high growth rates because a shift from migratory pastoralism to a more labour-intensive agro-pastoralist system helped to increase agricultural productivity. Additionally, land-use changes were linked to land privatisation and improved erosion protection on private land, decoupling population growth from environmental degradation. We detected, however also early warning signs of reduced community resilience as households were unable to fully recover livestock densities after catastrophic events. A population-growth driven reduction in household land-sizes and the decreased monetary value of agricultural production were identified as drivers of this development. The extrapolation of our results to establish a general relationship between population densities, land-use and household resilience in Sub-Saharan drylands suggest that further system transformations will be required to ensure regional food-security.
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7.
  • Carvalho, Ricardo, 1985-, et al. (författare)
  • Household Bioenergy Transitions with Alternative Biomass Feedstocks and Technologies: An Integrated System to Mitigate Environmental Risks in Western Kenya
  • 2018
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • In Kenya, over 50% of the total primary energy consumption is from traditional solid-fuel cooking, being this a major cause of deforestation and household air pollution (HAP). Western Kenya has an agricultural biofuel feedstock of over 1.9 million Mt, which could be processed to supply cookstoves with crop-residue pellets and improved wood fallows. The sociotechnical viability of two novel bioenergy value chains were analysed using the Long-Range Energy Alternatives Planning system. Three scenarios of transition to efficient cookstoves and decentralized biofuel and electricity production systems were tested. In the “Optimal scenario”, the current feedstock in the Kisumu and Siaya counties could satisfy over 80% of the cooking energy demand by 2030. Here, the net greenhouse gas emissions from charcoal production and HAP could be reduced by 87% to 12.6 thousand Mt CO2e. Further work should integrate socioeconomic indicators reflecting additional local/regional stakeholders´ collaboration channels (cost-effective) to support the bioenergy transitions. 
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8.
  • Carvalho, Ricardo L., et al. (författare)
  • Bioenergy strategies to address deforestation and household air pollution in western Kenya
  • 2019
  • Ingår i: European Biomass Conference and Exhibition Proceedings. - : ETA-Florence Renewable Energies. ; , s. 1536-1542
  • Konferensbidrag (refereegranskat)abstract
    • Over 640 million people in Africa are expected to rely on solid-fuels for cooking by 2040. In Western Kenya, cooking inefficiently persists as a major cause of burden disease due to household air pollution. The Long-Range Energy Alternatives Planning (LEAP) system and the Life-Cycle Assessment tool Simapro 8.5 were applied for analyzing biomass strategies for the region. The calculation of the residential energy consumption and emissions was based on scientific reviews and original data from experimental studies. The research shows the effect of four biomass strategies on the reduction of wood fuel use and short-lived climate pollutant emissions. A Business As Usual scenario (BAU) considered the trends in energy use until 2035. Transition scenarios to Improved Cookstoves (ICS), Pellet-fired Gasifier Stoves (PGS) and Biogas Stoves (BGS) considered the transition to wood-logs, biomass pellets and biogas, respectively. An Integrated (INT) scenario evaluated a mix of the ICS, PGS and BGS. The study shows that, energy use will increase by 8% (BGS), 20% (INT), 26% (PGS), 42% (ICS) and 56% (BAU). The BGS has the lowest impact on global warming, particle formation, terrestrial acidification, fossil resource scarcity, water consumption, as well as on eutrophication followed by the PGS and INT.
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9.
  • Carvalho, Ricardo Luís, et al. (författare)
  • Environmental Sustainability of Bioenergy Strategies in Western Kenya to Address Household Air Pollution
  • 2020
  • Ingår i: Energies. - : MDPI. - 1996-1073. ; 13:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Over 640 million people in Africa are expected to rely on solid-fuels for cooking by 2040. In Western Kenya, cooking inefficiently persists as a major cause of burden of disease due to household air pollution. Efficient biomass cooking is a local-based renewable energy solution to address this issue. The Life-Cycle Assessment tool Simapro 8.5 is applied for analyzing the environmental impact of four biomass cooking strategies for the Kisumu County, with analysis based on a previous energy modelling study, and literature and background data from the Ecoinvent and Agrifootprint databases applied to the region. A Business-As-Usual scenario (BAU) considers the trends in energy use until 2035. Transition scenarios to Improved Cookstoves (ICS), Pellet-fired Gasifier Stoves (PGS) and Biogas Stoves (BGS) consider the transition to wood-logs, biomass pellets and biogas, respectively. An Integrated (INT) scenario evaluates a mix of the ICS, PGS and BGS. In the BGS, the available biomass waste is sufficient to be upcycled and fulfill cooking demands by 2035. This scenario has the lowest impact on all impact categories analyzed followed by the PGS and INT. Further work should address a detailed socio-economic analysis of the analyzed scenarios.
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10.
  • Carvalho, Ricardo L., et al. (författare)
  • Household air pollution mitigation with integrated biomass/cookstove strategies in Western Kenya
  • 2019
  • Ingår i: Energy Policy. - : Elsevier. - 0301-4215 .- 1873-6777. ; 131, s. 168-186
  • Tidskriftsartikel (refereegranskat)abstract
    • Traditional cooking is today's largest global environmental health risk. Over 640 million people in Africa are expected to rely on biomass for cooking by 2040. In Kenya, cooking inefficiently with wood and charcoal persists as a cause of deforestation and household air pollution. This research analyses the effects of four biomass cookstove strategies on reducing air pollutant emissions in Kisumu County between 2015 and 2035 using the Long-Range Energy Alternatives Planning system. The Business as Usual scenario (BAU) was developed considering the historical trends in household energy use. Energy transition scenarios to Improved Cookstoves (ICS), Pellet Gasifier Stoves (PGS) and Biogas Stoves (BGS) were applied to examine the impact of these systems on energy savings and air pollution mitigation. An integrated scenario (INT) was evaluated as a mix of the ICS, PGS and BGS. The highest energy savings, in relation to the BAU, are achieved in the BGS (30.9%), followed by the INT (23.5%), PGS (19.4%) and ICS (9.2%). The BGS offers the highest reduction in the GHG (37.6%), CH4 (94.3%), NMVOCs (85.0%), CO (97.4%), PM2.5 (64.7%) and BC (48.4%) emissions, and the PGS the highest reduction in the N2O (83.0%) and NOx (90.7%) emissions, in relation to the BAU.
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11.
  • Dahlin, Sigrun, et al. (författare)
  • Effect of grass-diet and grass-legume-diet manure applied to planting holes on smallholder maize production in Rwanda
  • 2021
  • Ingår i: Field Crops Research. - : Elsevier BV. - 0378-4290 .- 1872-6852. ; 263
  • Tidskriftsartikel (refereegranskat)abstract
    • Animal manure provides plant nutrients and also affects soil nutrient availability, pH buffering and soil physical properties through its contribution to soil organic matter pools. However, the quality and quantity of manure are often low on smallholder farms in sub-Saharan Africa and the initial effect of manuring on crop yield may be small or even negative. In a two-factorial experiment over four seasons in southern Rwanda, the fertiliser value to a maize crop of manures produced by cattle fed a basal diet of only Chloris gayana grass or a mixed C. gayanaAcacia angustissima diet was compared with that of NPK 17-17-17 and no fertiliser. The potential liming effect of the manures was also evaluated through inclusion (or not) of travertine as the second factor. All amendments were applied only to maize planting holes. The crop failed in season 1 due to drought, but manure application (5 t ha-1) approximately doubled maize yield compared with the unfertilised control during seasons 2-4, while NPK (70 kg N ha-1) increased yield by 3- to 4-fold, with corresponding improvements in crop performance indicators. The mixed diet increased manure quality and maize yield compared with the grass diet in season 4. Liming showed a consistent tendency to improve crop performance indicators and yield, but significant differences were only identified in some cases, possibly because the pH increase was small. The results suggest that in regions where manure availability is limiting, application of reduced rates only to planting holes may be an efficient technology. Enhanced animal feed can result in higher quality manure, and ultimately increase crop yield, if nutrient losses during manure handling and storage can be limited.
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12.
  • Egberth, Mikael, et al. (författare)
  • Combining airborne laser scanning and Landsat data for statistical modeling of soil carbon and tree biomass in Tanzanian Miombo woodlands
  • 2017
  • Ingår i: Carbon Balance and Management. - : BioMed Central (BMC). - 1750-0680. ; 12:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Soil carbon and biomass depletion can be used to identify and quantify degraded soils,and by using remote sensing, there is potential to map soil conditions over large areas.Landsat 8 Operational Land Imager satellite data and airborne laser scanning datawere evaluated separately and in combination for modeling soil organic carbon, aboveground tree biomass and below ground tree biomass. The test site is situated in theLiwale district in southeastern Tanzania and is dominated by Miombo woodlands. Treedata from 15m radius field-surveyed plots and samples of soil carbon down to a depthof 30cm were used as reference data for tree biomass and soil carbon estimations.Cross-validated plot level error (RMSE) for predicting soil organic carbon was 28%using only Landsat 8, 26% using laser only, and 23% for the combination of the two.The plot level error for above ground tree biomass was 66% when using only Landsat8, 50% for laser and 49% for the combination of Landsat 8 and laser data. Results forbelow ground tree biomass were similar to above ground biomass. Additionally it wasfound that an early dry season satellite image was preferable for modelling biomasswhile images from later in the dry season were better for modelling soil carbon.The results show that laser data is superior to Landsat 8 when predicting both soilcarbon and biomass above and below ground in landscapes dominated by Miombowoodlands. Furthermore, the combination of laser data and Landsat data weremarginally better than using laser data only.
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13.
  • Ekblad, Alf, 1957-, et al. (författare)
  • C-13-discrimination during microbial respiration of added C-3-, C-4- and C-13-labelled sugars to a C-3-forest soil
  • 2002
  • Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 131:2, s. 245-249
  • Tidskriftsartikel (refereegranskat)abstract
    • We tested whether 13C-discrimination during microbial respiration, or during CO2 sampling in the field, can explain changes observed in the δ13C of emitted CO2 that follow the addition of C4-sucrose, as a microbial substrate, to the soil of a C3-ecosystem. We approached this problem by adding C3-glucose (δ13C=–23.4‰), C4-sucrose (–10.8‰) or 13C-labelled glucose (103.7‰) to the intact mor layer, the upper organic soil (–26.5‰, bulk soil organic matter), of a boreal Pinus sylvestris L. forest. If 13C-discrimination is significant, it should generate illusory differences in the calculated contributions from the added C and endogenous C3-C to total soil respiration, when C4-sucrose or 13C-labelled glucose is added. Further, if discrimination occurs, we should also be able to detect a shift in the δ13C of respired CO2 after the addition of C3-glucose. The addition of the three sugar solutions gave similar increases in soil respiration (up to a doubling 1 h after the additions), while the addition of water gave no increase in respiration. There was no change in δ13C of the emitted CO2 after additions of H2O or C3-glucose. In contrast, the addition of C4-sucrose and 13C-labelled glucose gave δ13C values of evolved CO2 that were 4.5‰ and 30.3‰ higher than the pre-sugar values, respectively. The calculated respiration rates of the added carbon sources, C4-C or 13C-labelled C, were very similar. Also, we found very similar sugar-induced increases in respiration of endogenous C3-C in the plots supplied with C4-sucrose and 13C-labelled glucose, accounting for about 50% of the total increase in respiration 1 h after addition. Our results confirm that any microbial 13C-discrimination during respiration is minor.
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14.
  • García-López, Naxto, et al. (författare)
  • An integrated agroforestry-bioenergy system for enhanced energy and food security in rural sub-Saharan Africa
  • 2024
  • Ingår i: Ambio. - 0044-7447 .- 1654-7209.
  • Tidskriftsartikel (refereegranskat)abstract
    • Most people in rural sub-Saharan Africa lack access to electricity and rely on traditional, inefficient, and polluting cooking solutions that have adverse impacts on both human health and the environment. Here, we propose a novel integrated agroforestry-bioenergy system that combines sustainable biomass production in sequential agroforestry systems with biomass-based cleaner cooking solutions and rural electricity production in small-scale combined heat and power plants and estimate the biophysical system outcomes. Despite conservative assumptions, we demonstrate that on-farm biomass production can cover the household’s fuelwood demand for cooking and still generate a surplus of woody biomass for electricity production via gasification. Agroforestry and biochar soil amendments should increase agricultural productivity and food security. In addition to enhanced energy security, the proposed system should also contribute to improving cooking conditions and health, enhancing soil fertility and food security, climate change mitigation, gender equality, and rural poverty reduction.
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15.
  • Högberg, Peter, et al. (författare)
  • Large-scale forest girdling shows that current photosynthesis drives soil respiration
  • 2001
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 411:6839, s. 789-792
  • Tidskriftsartikel (refereegranskat)abstract
    • The respiratory activities of plant roots, of their mycorrhizal fungi and of the free-living microbial heterotrophs (decomposers) in soils are significant components of the global carbon balance, but their relative contributions remain uncertain. To separate mycorrhizal root respiration from heterotrophic respiration in a boreal pine forest, we conducted a large-scale tree-girdling experiment, comprising 9 plots each containing about 120 trees. Tree-girdling involves stripping the stem bark to the depth of the current xylem at breast height terminating the supply of current photosynthates to roots and their mycorrhizal fungi without physically disturbing the delicate root-microbe-soil system. Here we report that girdling reduced soil respiration within 1-2 months by about 54% relative to respiration on ungirdled control plots, and that decreases of up to 37% were detected within 5 days. These values clearly show that the flux of current assimilates to roots is a key driver of soil respiration; they are conservative estimates of root respiration, however, because girdling increased the use of starch reserves in the roots. Our results indicate that models of soil respiration should incorporate measures of photosynthesis and of seasonal patterns of photosynthate allocation to roots.
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16.
  • Ilstedt, Ulrik, et al. (författare)
  • Intermediate tree cover can maximize groundwater recharge in the seasonally dry tropics
  • 2016
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
  • Tidskriftsartikel (refereegranskat)abstract
    • Water scarcity contributes to the poverty of around one-third of the world's people. Despite many benefits, tree planting in dry regions is often discouraged by concerns that trees reduce water availability. Yet relevant studies from the tropics are scarce, and the impacts of intermediate tree cover remain unexplored. We developed and tested an optimum tree cover theory in which groundwater recharge is maximized at an intermediate tree density. Below this optimal tree density the benefits from any additional trees on water percolation exceed their extra water use, leading to increased groundwater recharge, while above the optimum the opposite occurs. Our results, based on groundwater budgets calibrated with measurements of drainage and transpiration in a cultivated woodland in West Africa, demonstrate that groundwater recharge was maximised at intermediate tree densities. In contrast to the prevailing view, we therefore find that moderate tree cover can increase groundwater recharge, and that tree planting and various tree management options can improve groundwater resources. We evaluate the necessary conditions for these results to hold and suggest that they are likely to be common in the seasonally dry tropics, offering potential for widespread tree establishment and increased benefits for hundreds of millions of people
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17.
  • Karmebäck, Vera, et al. (författare)
  • Assessing gender roles in a changing landscape: diversified agro-pastoralism in drylands of West Pokot, Kenya
  • 2015
  • Ingår i: Pastoralism. - : Springer Science and Business Media LLC. - 2041-7128 .- 2041-7136. ; 5:21
  • Tidskriftsartikel (refereegranskat)abstract
    • Previous studies in drylands have shown that while gender roles are becoming more flexible, privatization and formalization of land tenure tends to marginalize women in drylands while environmental degradation leads to differential changes in gender workload. Chepareria, a ward in West Pokot County, has undergone the above-mentioned tenure and environmental changes and is nowadays dominated by private enclosures as a land management approach. This study reviewed in which ways these rangeland enclosures have influenced gender roles in the dryland systems of Chepareria in West Pokot, with specific regard to division of labour, financial responsibilities and decision-making processes on the household level, and also tries to identify the underlying driving forces that have contributed to the observed changes.Our results indicate that the workload of women has increased under new land fragmentation processes in rangelands due to increased responsibilities in cattle herding and income generation, but also that due to this, women have gained higher influence in household decisions concerning the family economy. It was found that women to a larger extent than before are engaged in small-scale business such as the selling of farm products and poultry keeping, hence getting financial resources under their own control. In this way, women are involved in decision-making processes and income generation to a higher extent than before, though they are still excluded from certain traditionally male-dominated spheres both within and beyond the household, such as the sale of cattle and the handling of larger amounts of financial resources.Under the new land fragmentation processes in Chepareria, women are increasingly seen as crucial income earners and they are enjoying a higher degree of financial independence, more decision-making power and a louder voice than before in household and public matters.
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18.
  • Knutsson, Per, 1971, et al. (författare)
  • Perspectives on enclosures in pastoralist drylands: From contradictory evidence to the formulation of innovative land management strategies
  • 2021
  • Ingår i: World Development Perspectives. - : Elsevier BV. - 2452-2929 .- 2468-0532. ; 23
  • Tidskriftsartikel (refereegranskat)abstract
    • Drylands in Sub-Saharan Africa are subject to rapid and enduring population increase, agricultural expansion, land large-scale infrastructure developments, as well as climate change, affecting some 265 million pastoralists and agro-pastoralists. These changes are promoting a transition from traditional pastoralist ways of life characterized by seasonal mobility, towards more sedentary livelihoods based on more intensive and commercial uses of land-based resources. As part of of this ongoing transition, establishment of enclosures on pastoralist commons is emerging as a default, but highly contested, development pathway. Based on a review of the current enclosure debate across the natural, economic, and social sciences, with a geographical focus on the East African drylands, we discuss the potential and limitations of enclosures as land management tool, and propose a conceptual framework for how enclosures can act as an integral part of sustainable pastoralist land use. Such a framework constitute an important piece of the puzzle for more productively linking the urgent need of innovative ways of managing pastoralist rangelands, to the present international and national commitments to restoration of degraded lands.
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19.
  • Kätterer, Thomas, et al. (författare)
  • Biochar addition persistently increased soil fertility and yields in maize-soybean rotations over 10 years in sub-humid regions of Kenya
  • 2019
  • Ingår i: Field Crops Research. - : Elsevier BV. - 0378-4290 .- 1872-6852. ; 235, s. 18-26
  • Tidskriftsartikel (refereegranskat)abstract
    • Application of biochar has been shown to increase soil fertility and enable soil carbon sequestration, indicating potential for agricultural and environmental benefits from using locally produced biochar on African smallholder farms. However, previous studies have been rather short-term and little is known about the longer-term effects of biochar application on crop yields. Biochar contains ash, but the potential liming effect and nutrient release from ash may be short-lasting. To investigate long-term effects, we set up a series of field trials replicated at three sites in Kenya in 2006. The trials are still on-going and are possibly the longest biochar trials in sub-Saharan Africa. Here, we report effects on crop yield and soil properties over 10 years after applying biochar, produced mainly from Acacia spp., at a rate of 50 + 50 Mg ha(-1) during the first two seasons. Maize (Zea mays) and soybean (Glycine max) were grown in rotation, with or without inorganic fertiliser, and crop yield was monitored. For comparison of soil properties, additional plots were kept in bare fallow. Biochar addition slightly increased soil porosity, pH, plant-available phosphorus and soil water-holding capacity. Crop yield responded positively to biochar at all sites and yield responses were similar with and without mineral fertiliser, i.e., the effects of biochar and mineral fertiliser were additive. The seasonal yield increase due to biochar application was in average around 1.2 Mg ha(-1) for maize and 0.4 Mg for soybean, independently of fertilisation, over seasons and sites. Application of mineral fertiliser to maize increased maize yield by 1.6 Mg ha(-1) and the subsequent, unfertilized soybean yield by 0.6 Mg ha(-1), illustrating a carry-over effect. Most importantly, the effect on maize and soybean yield of adding biochar to soil persisted over the whole 10-year period. Analysis of the carbon (C) balance in topsoil indicated that about 40% of biochar C was apparently lost through mineralization, erosion or vertical translocation. Moreover, changes in soil carbon/nitrogen ratios indicated that biochar application increased nitrogen mineralization from native soil organic matter.
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20.
  • Kätterer, Thomas, et al. (författare)
  • Maize grain yield responses to realistic biochar application rates on smallholder farms in Kenya
  • 2022
  • Ingår i: Agronomy for Sustainable Development. - : Springer-Verlag Italia s.r.l.. - 1774-0746 .- 1773-0155. ; 42:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite efforts to increase agricultural production sustainably in sub-Saharan Africa, large gaps remain between actual and potential yield of food crops. Adding biochar to degraded cropland soils in the African tropics has significant potential to enhance crop productivity. Biochar-based farming can also mitigate climate change, through soil carbon storage. This study involved six smallholder farms at sites in eastern, central, and western Kenya that are characterized by different pedo-climatic conditions. We examined the response of non-fertilized and fertilized maize monoculture to three dosages of biochar that are realistic for domestic production by farmers at each of the sites over four growing seasons. Commonly available biomass wastes in each agro-ecosystem (coconut shells, coffee husks, maize cobs) were used as feedstock for biochar, which was applied at 1, 5, and 10 Mg ha−1 at the start of the experiment. Across seasons and fertilizer treatments, maize grain yield (dry matter) showed consistently positive responses, with an average increase of 1.0, 2.6, and 4.0 Mg ha−1, respectively, above the control for the three biochar application rates. Absolute responses of maize grain yield to specific biochar doses were similar across the four investigated seasons and replicate farms within sites, and uncorrelated to yield levels in the control treatment. Here, we show for the first time that yield response to biochar decreased with increasing application rate, indicating that it may be better to spread a given amount of biochar over a large area rather than concentrating it to a smaller area, at least when biochar is applied along plant rows at rates ≥1 Mg ha−1, as in our experiment. This study demonstrated that application of biochar, locally produced from available biomass residues, is a promising approach to enhance agricultural production and carbon storage on smallholder farms under a wide range of pedo-climatic conditions in Kenya. 
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21.
  • Lulandala, Lufunyo, et al. (författare)
  • Excessive livestock grazing overrides the positive effects of trees on infiltration capacity and modifies preferential flow in dry Miombo woodlands
  • 2022
  • Ingår i: Land Degradation and Development. - : Wiley. - 1085-3278 .- 1099-145X. ; 33, s. 581-595
  • Tidskriftsartikel (refereegranskat)abstract
    • The increase in livestock grazing in African drylands such as miombo woodlands threatens land productivity and ecosystem functioning. Trees have positive effects on soil hydraulic properties, but few studies have looked at grazing intensity and hydrological functioning in different land uses. Therefore, we conducted a biophysical survey in Morogoro Rural District, Tanzania, where we identified four main land uses and land cover types, that is, Forest reserve, open-access forest, cropland under fallow, and active cropland. We assessed grazing intensity, measured infiltration capacity, and conducted dye tracer experiments to assess the degree of preferential flow in 64 plots. We also tested the effect of grazing exclusion on infiltration capacity in 12-year-old fenced plots. Our results show that irrespective of land use or cover type, soil bulk density increased by 10% from low to high grazing intensity, whereas infiltration capacity and soil organic carbon decreased by 55% and 28%, respectively. We found a positive relationship between infiltration capacity and tree basal area in plots with lowest grazing intensities. However, at higher grazing, the infiltration capacity remained low independently of the basal area. Preferential flow in deeper soils was six-times higher in areas with no grazing, indicating higher deep soil and groundwater recharge potential at low grazing intensities. We conclude that the negative impacts on soil hydrological functioning of excessive livestock grazing override the positive effect of trees, but restricting grazing can reverse the impact.
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22.
  • Lulandala, Lufunyo, et al. (författare)
  • The size of clearings for charcoal production in miombo woodlands affects soil hydrological properties and soil organic carbon
  • 2023
  • Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 529
  • Tidskriftsartikel (refereegranskat)abstract
    • Charcoal production is a major driver of forest degradation in miombo woodlands. Forests play a crucial role in regulating the hydrological cycle, so it is critical to understand how forest degradation and management practices impact water availability, particularly in drylands. Few studies have examined the effect of forest clearing size on the hydrological functioning of soil, particularly under real-world conditions where, following clearing, forests are subject to multiple and prolonged anthropogenic disturbances, as occurs in miombo woodlands which are cleared for charcoal production and commonly used for livestock grazing. The pilot project Transforming Tanzania's Charcoal Sector was established in 2012 with the aim of establishing a sustainable wood harvesting system for charcoal production based on rotational harvesting cycles that allow for natural forest regeneration. Two clearing sizes were established: large clearings (300 × 300 m) harvested by clear-felling, and small clearings (50 × 50 m) harvested in a checkerboard pattern. We examined the effect of these two clearing sizes on soil hydrological properties and soil organic carbon (SOC) in Kilosa district, Morogoro, Tanzania. Our analysis included four treatments: large clearings, small clearings, small intact plots (unharvested plots within the checkboard pattern), and village land forest reserve. For each treatment we assessed the tree cover and measured soil infiltration capacity, soil bulk density, SOC stock, and texture. We also examined the relationship between these variables and the distance to the closest road to better understand the impact of livestock and human disturbance. Our results show that large clearings had the lowest mean infiltration capacity (121 ± 3 mm h−1) and SOC stock content (12 ± 0.2 tonnes ha−1), and the highest bulk density (1.6 ± 0.005 g cm−3) of all the treatments. We found a positive relationship between infiltration capacity and basal area (R2 = 0.71) across all treatments. We also found that infiltration capacity, SOC stock and tree basal area increased with increasing distance from the closest road, while bulk density decreased. We conclude that, in terms of their impact on soil hydrological functioning and SOC stock, small clearings, while not completely unaffected, are better than larger ones. In small clearings, concurrent reductions in tree cover and a relatively low impact on soil hydrological properties could result in increased soil and groundwater recharge compared to unharvested forest areas. Controlling livestock grazing can further minimize soil degradation, producing additional gains.
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23.
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24.
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25.
  • Mahmoud, Yahia, et al. (författare)
  • Biochar production and application in small-scale farming in Kenya : Yield increases and local perceptions
  • 2019
  • Konferensbidrag (refereegranskat)abstract
    • Degradation of agricultural soils and forest resources are two pervasive challenges in rural landscapes of sub-Saharan Africa. Biochar-producing biomass gasification technologies attract evermore interest because these can empower small-scale farmers to produce energy and food more sustainably byimproving energy use efficiencies, lowering emissions and strengthening climate resilience. In order to assess the potential impacts and the feasibility of soil biochar amendments we are carrying out on-farm trials with 150 households in three agroecosystems in Kenya. A participatory approach was followed for testing uptake of gasifier cook stoves and effects of biochar use on crop production. The outcomes that will be presented include: (a) the degree of feasibility, (b) the effects on crop yields, (c) the general attitudes towards the idea of using the cookstoves to produce biochar, and (d) patterns of biomass fuel use. Effects of domestically produced biochar, at rates of 1-10 t DW ha-1, on the production of maize (Zea mays) and kale (Brassica oleracea) were compared with normal farming practices. At the site located in Kwale the yield increases of maize showed a strong positive correlation with biochar dose. In the first season, yields increased from 0.9 Mg ha-1 in the control plot to 4.4Mg ha-1 in average in the biochar-amended plots. At another site (Siaya), an average biochar dose of 2.8 Mg ha-1 lead to an increase in maize yields from 2.9 to 3.8 Mg ha-1 in average in the first season and from 1.7 to 2.5 Mg ha-1 in the second season after biochar addition. Findings from this action research indicate that producing and using biochar on small-scale farms offers suitable opportunities to close yield gaps across Kenya and in similar agro-ecological environments.
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26.
  • Mukangango, Marguerite, et al. (författare)
  • Biomass production and nutrient content of three agroforestry tree species growing on an acid Anthropic Ferralsol under recurrent harvesting at different cutting heights
  • 2020
  • Ingår i: Agroforestry Systems. - : Springer Science and Business Media LLC. - 0167-4366 .- 1572-9680. ; 94, s. 857-867
  • Tidskriftsartikel (refereegranskat)abstract
    • Agroforestry systems may alleviate challenges relating to soil degradation and low livestock production for smallholder farmers. Species-adjusted management regimes will determine how agroforestry fits in farming systems. Long-term productivity of biomass in agroforestry systems managed for fodder production requires tree species that coppice after repeated cutting. This study evaluated the effect of different cutting heights (0.3 and 1.0 m) and repeated harvests (1-5) on biomass production and chemical composition of the leguminous trees Acacia angustissima, Leucaena pallida and Mimosa scabrella in a field study on an Anthropic Ferralsol in Southern Rwanda. Shoot biomass production was highest at 0.3 m cutting height for A. angustissima and L. pallida, but M. scabrella could not survive that cutting height. Shoot biomass was highest for A. angustissima and lowest for M. scabrella, which did not adapt to repeated harvests. Leaf:stem ratio was not affected by cutting height. Cutting height did not affect crude protein (CP), but neutral detergent fibre (NDF), acid detergent fibre (ADF) and total polyphenol (TP) concentrations were higher at 1.0 m cutting height than at 0.3 m. Crude protein was highest in A. angustissima and lowest in M. scabrella, while NDF and ADF were highest in M. scabrella. Although all species provided high feed quality in terms of high CP content at both cutting heights, low cutting height (0.3 m) is recommended for A. angustissima and L. pallida for higher overall quality and biomass production.
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27.
  • Mukangango, Marguerite, et al. (författare)
  • Supplementing grass-based cattle feeds with legume leaves and its effects on manure quality and value as a soil improver for an Anthropic Ferralsol in Rwanda
  • 2020
  • Ingår i: Experimental Agriculture. - 0014-4797 .- 1469-4441. ; 56, s. 483-494
  • Tidskriftsartikel (refereegranskat)abstract
    • Combined use of lime, animal manure and inorganic fertilisers is effective in replenishing the fertility of degraded acid soils. However, many smallholder farmers lack access to sufficient amounts of these inputs to improve the fertility and reduce the aluminium toxicity of Ferralsols. Organic manures are available but often have low nutrient content, which limits their ability to supply nutrients to soils. In a two-factor field experiment over four seasons on an Anthropic Ferralsol in Southern Province, Rwanda, we assessed (i) the effect of cattle manure on soil properties at a reduced rate affordable to smallholder farmers compared with that of NPK fertiliser applied, with and without lime also at a reduced rate, and (ii) the effect of supplementing grass in a basal cattle diet with legume leaves on manure quality and its effect on soil properties. Manure from cattle fed only the grassChloris gayana(grass-only manure) and from cattle fedC. gayanasupplemented withAcacia angustissimaleaves (grass+legume manure) was applied at 5 t dry matter ha(-1)(25% of the recommended rate) at the beginning of each growing season. NPK was applied as split doses supplying a total rate of 70 kg N ha(-1). Lime was applied annually at a rate of 2.0 t CaO ha(-1), which was 25% of the rate required to neutralise total acidity at the site. All amendments were applied only to the soil surrounding the maize plants (planting stations), which is estimated at 25% of the plot area. Maize stover was left on plots after harvest and planting stations were retained over all growing seasons. All treatments altered soil properties at the planting stations. Lime generally increased pH but there was no significant difference between lime plus manure treatments and non-limed manure treatments. Soil organic carbon concentration and cation exchange capacity were higher in manure and NPK treatments than in non-fertilised treatments. The manure treatment increased soil water-holding capacity compared with the NPK and non-fertilised treatments. There was no significant difference in total N, Ca2+, Mg(2+)and K(+)between the NPK and manure treatments. Micro-dosing animal manure can thus replace mineral fertiliser plus lime for soil fertility replenishment in smallholder farming. Grass+legume manure contained higher concentrations of total N, Ca, Mg, K and Na than grass-only manure, but its effect on soil properties did not differ significantly from that of grass-only manure.
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28.
  • Nyberg, Gert (författare)
  • Benefits Derived from Rehabilitating a Degraded Semi-Arid Rangeland in Private Enclosures in West Pokot County, Kenya
  • 2016
  • Ingår i: Land Degradation and Development. - : Wiley. - 1085-3278 .- 1099-145X. ; 27, s. 532-541
  • Tidskriftsartikel (refereegranskat)abstract
    • Rehabilitating degraded rangelands using enclosures offers various benefits to agro-pastoral households. However, enclosure benefits cannot be generalized as there are variations across dryland ecosystems and societies. This study assessed the qualitative and quantitative benefits derived from rehabilitating degraded rangelands using private enclosures in Chepareria, West Pokot County, Kenya. Dry-season grazing reserves, healthier livestock, improved livestock productivity, easier livestock management, food security, reduced animal losses, ecosystem services, land ownership, independence and improved standard of living were the main qualitative benefits from private enclosures identified. Quantitative benefits were manifested through various enclosure enterprise combinations, sale of enclosure marketable products and adoption of alternative income generating activities. They included the sale of livestock and livestock products, maize, wood cutting, grass cuttings, contractual grazing, grass seeds, poultry products, fruits and honey, amongst others. Livestock production directly accounts for 424% of the total enclosure income and is the main source of livelihood in Chepareria. There was a significant trend of increasing total enclosure income with enclosure acreage (p005) while enclosure age was insignificant. Enclosures cushion households against climatic shocks such as drought by providing additional flexibility in land, fodder, livestock management and the uptake of various income generating activities. We conclude that enclosures have the potential of contributing to resilience as attested from the benefits reported in this study. However, private enclosure tradeoffs such income differentiation, reduced communal land and conflict have implications on how the ecological and socio-economic aspects may be impacted as the establishment of private enclosures in Chepareria continues. Copyright (c) 2015 John Wiley & Sons, Ltd.
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29.
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30.
  • Nyberg, Gert (författare)
  • Enclosing the commons: reasons for the adoption and adaptation of enclosures in the arid and semi-arid rangelands of Chepareria, Kenya
  • 2015
  • Ingår i: SpringerPlus. - : Springer Science and Business Media LLC. - 2193-1801. ; 4, s. 1-11
  • Tidskriftsartikel (refereegranskat)abstract
    • The adoption and adaptation of enclosures in the arid and semi-arid rangelands of sub-Saharan Africa is driven and sustained by a combination of factors. However, reviews indicate that these factors cannot be generalized, as they tend to be case specific. A study was therefore conducted to explore the history and reasons for enclosure establishment in Chepareria, a formerly degraded communal rangeland in north-western Kenya. While Vi-Agroforestry Organization accounting for 52.5 % was the main source of knowledge on enclosure establishment; it has now emerged that rangeland enclosures among the Pokot pastoral community existed prior to land management interventions by Vi-Agroforestry. Results indicated that there are three categories of enclosures which were established for boundary demarcation, provide grazing reserves, enable proper land management, facilitate crop cultivation in a pastoral setup and to curb land degradation. The role of self-trigger [accounting for most of the spontaneous enclosures (73.5 %)] indicates the continued establishment and expansion of areas under enclosure management as private land ownership accounting for 51.7 % of enclosure tenure continues to gain momentum in Chepareria. While rangeland enclosures in Chepareria were mainly established for boundary demarcation, to alleviate pasture scarcity and enable proper management of formerly degraded areas; they have facilitated land restoration and rehabilitation by increasing flexibility in land, fodder and livestock management amongst agro-pastoralists in Chepareria over the last three decades. To ensure that rehabilitated areas do not revert to their previously degraded state; technical interventions are needed to allow for a more intensive use of rangeland resources within enclosed areas.
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31.
  • Nyberg, Gert, et al. (författare)
  • Enclosures as a land management tool for food security in African drylands
  • 2019
  • Ingår i: Journal of Land Use Science. - : TAYLOR & FRANCIS LTD. - 1747-4248 .- 1747-423X. ; 14:1, s. 110-121
  • Forskningsöversikt (refereegranskat)abstract
    • Increasing sedentary agro-pastoralist livelihoods may be explained by land degradation, population pressure, agricultural commodification, and economic development. We reviewed scientific and ‘grey’ literature for the effects of enclosures on food security. Only 8% of the 114 reviewed scientific articles addressed food production, while 69% approached environmental parameters that indirectly affect food security, most of which had positive results. Thirty-one percent focused on social and economic impacts, land tenure conflicts and elite capture with negative connotations. The ‘grey’ literature showed an opposite balance between positive environmental views and negative socio-economic impacts. Enclosures are not a panacea for dryland development, but their use need to be recognized and understood. Multidisciplinary research and cooperation on the applied management of enclosures in the context of food security is highly needed. Furthermore, agro-pastoralist land-use practices need more policy space and practical management support, such as clear tenure legislation, agroforestry methodologies, and support in fodder production systems.
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32.
  • Nyberg, Gert, et al. (författare)
  • Enclosures in West Pokot, Kenya: Transforming land, livestock and livelihoods in drylands
  • 2015
  • Ingår i: Pastoralism. - : Springer Science and Business Media LLC. - 2041-7136 .- 2041-7128. ; 5:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Dryland livestock production systems are changing in many parts of the world, as a result of growing human populations and associated pressure on water and land. Based on a combination of social and natural science methods, we studied a 30-year transformation process from pastoralism to a livestock-based agro-pastoral system in northwestern Kenya, with the overall aim to increase the understanding of the ongoing transition towards intensified agro-pastoralist production systems in dryland East Africa.Key to this transformation was the use of enclosures for land rehabilitation, fodder production, and land and livestock management. Enclosures have more soil carbon and a higher vegetation cover than adjacent areas with open grazing. The level of adoption of enclosures as a management tool has been very high, and their use has enabled agricultural diversification, e.g. increased crop agriculture, poultry production and the inclusion of improved livestock. Following the use of enclosures, livelihoods have become less dependent on livestock migration, are increasingly directed towards agribusinesses and present new opportunities and constraints for women. These livelihood changes are closely associated with, and depend on, an ongoing privatization of land under different tenure regimes.The results indicate that the observed transformation provides opportunities for a pathway towards a sustainable livestock-based agro-pastoral system that could be valid in many dryland areas in East Africa. However, we also show that emergent risks of conflicts and inequalities in relation to land, triggered by the weakening of collective property rights, pose a threat to the sustainability of this pathway.
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33.
  • Nyberg, Gert (författare)
  • Enhancing soil organic carbon, particulate organic carbon and microbial biomass in semi-arid rangeland using pasture enclosures
  • 2018
  • Ingår i: BMC Ecology. - : Springer Science and Business Media LLC. - 1472-6785. ; 18
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundRehabilitation of degraded rangelands through the establishment of enclosures (fencing grazing lands) is believed to improve soil quality and livelihoods, and enhance the sustainability of rangelands. Grazing dominated enclosure (GDE) and contractual grazing enclosure (CGE) are the common enclosure management systems in West Pokot County, Kenya. Under CGE, a farmer owning few animals leases the enclosure to households with relatively more livestock, while GDE is where the livestock utilizing the enclosure are purely owned by the farmer. Livestock management in both systems is via the free-range system. This study evaluated the effect of enclosure management on total soil organic carbon (SOC), particulate organic carbon (POC) and microbial biomass carbon (MBC) and nitrogen (MBN) as key indicators of soil degradation at 0-40cm depth. The two enclosure systems were selected based on three age classes (3-10, 11-20 and >20years since establishment) (n=3). The adjacent open grazing area (OGR) was used as a reference (n=9).ResultsRelative to OGR, the pasture enclosures significantly decreased soil bulk density and increased the concentrations of total organic C, POC, MBC and MBN compared to the degraded OGR (P<0.001). Significantly higher concentrations of POC and MBC was recorded in GDE than CGE (P=0.01). The POC accounted for 24.5-29.5% of the total SOC. MBC concentrations ranged from 32.057.25 to 96.63 +/- 5.31 mu gCg(-1) of soil in all grazing systems, and was positively correlated with total SOC and POC (P<0.001). The proportional increase in POC and MBC was higher in GDE (56.6 and 30.5% respectively) compared to CGE (39.2 and 13.9% for POC and MBC respectively).Conclusions This study demonstrated that controlling livestock grazing through the establishment of pasture enclosures is the key strategy to enhance total SOC, POC, MBC, and MBN in degraded rangelands; a precondition for improving soil quality. Therefore, the establishment of enclosures is an effective restoration approach to restore degraded soils in semi-arid rangelands.
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34.
  • Nyberg, Gert (författare)
  • Fuelwood use and household appreciation of improved and traditional cooking stoves in Rwanda
  • 2024
  • Ingår i: Biomass and Bioenergy. - 0961-9534 .- 1873-2909. ; 186
  • Tidskriftsartikel (refereegranskat)abstract
    • More than 90 % of the rural population in Rwanda (72 % of the total population) utilizes the inefficient traditional three-stone fireplaces (TSF), and 65 % of the urban population uses charcoal for cooking. Firewood is bulky and heavy to transport and store in urban areas, and charcoal stoves are more efficient and less smoky than TSF. However, most energy and wood are lost when converting firewood to charcoal. Traditional charcoal kiln often has an average of 12 % conversion efficiencies in Rwanda. Several improved cooking stoves (ICS) have been developed as alternatives to the TSF and charcoal stoves, but their efficiencies and household appreciation in real-life conditions are poorly understood. This study assesses the fuelwood use efficiency of two ICSs, MimiMoto and Kuniokoa stoves. The Kuniokoa is a rocket stove that uses firewood, while the MimiMoto is a toplit-up-draft (TLUD) gasification stove fuelled with wood pellets. The MimiMoto stoves were delivered to 15 selected households using charcoal stoves, while the Kuniokoa stoves were given to 30 households using TSF. The amount of wood consumed and time spent during cooking were recorded for a standardized traditional dish. The Kuniokoa stove consumed 0.9kg/cooking session, while the TSF consumed 1.6 kg/cooking session. Switching from TSF to Kuniokoa stoves in rural areas reduces fuelwood consumption by 41 %. MimiMoto and charcoal stoves consume 0.50 and 0.48 kg/cooking session. However, 0.48 kg charcoal is equivalent to 4 kg firewood; hence, switching from charcoal stoves to MimiMoto stoves results in a firewood reduction of 88 %. Analysis of cooking times shows small differences between TSF, Kuniokoa, and MimiMoto, around 55-60 min, while cooking on charcoal takes significantly more time. The ICSs were highly appreciated by participating households, especially for their fuel saving, ease of use, reduced smokiness, and general cleanliness. Based on the results, it can be concluded that efficient rocket stoves, like Kuniokoa, are viable alternatives to TSF for household cooking in rural areas and that efficient TLUD stoves, like the MimiMoto, are good alternatives to replace charcoal stoves in urban and peri-urban areas. Aggregated to annual and national scales, such changes would have substantial positive implications for the environment and livelihoods.
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35.
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36.
  • Nyberg, Gert (författare)
  • Mapping land enclosures and vegetation cover changes in the surroundings of Kenya's Dadaab refugee camps with very high resolution satellite imagery
  • 2019
  • Ingår i: Land Degradation and Development. - : Wiley. - 1085-3278 .- 1099-145X. ; 30, s. 253-265
  • Tidskriftsartikel (refereegranskat)abstract
    • The immediate surroundings of refugee camps in drylands are among the areas exposed to highest pressure on natural resources including vegetation and soil. Understanding the dynamics of land fencing in these areas is critical for sustainable camp management and can help to improve the knowledge about land management in drylands in general. Very high resolution satellite imagery provides a means to observe such areas over time and to document land cover and use changes. This study uses satellite images to map fenced areas, which can be divided into pastoral enclosures and the so called 'green belts' (areas fenced for afforestation) around the Hagadera Camp in Dadaab (Kenya). It then analyses change dynamics between 2006 and 2013, a period where the refugee camp has been subject to high oscillations in camp population, due to a combination of conflicts and droughts in Somalia. The applied methodology allows detailed fence mapping and shows a large increase in fenced area (56%) over the 7-year period. Although new pastoral enclosures expanded into more densely vegetated surroundings, land cover density inside already fenced areas either decreased or remained stable. Green belt areas grew at a similar rate (58%) but did not show evidence of greening over time and their longer term success is strongly dependent on maintenance. The settlement area did also expand remarkably in the same time (65%), and human and animal movements in the surroundings intensified with a negative impact on vegetation density. The study could not fully investigate the socio-economic drivers and impacts linked to the rapid increase of enclosures, which are inextricably linked to evolutions in local agro-pastoral practices. However, by documenting spatial and temporal dynamics of fenced areas, it adds new evidence to their increasing relevance in rangeland management, and opens the way to a number of hypotheses, stimulating the debate about long-term ecological and socio-economic impact.
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37.
  • Nyberg, Gert (författare)
  • Pasture enclosures increase soil carbon dioxide flux rate in Semiarid Rangeland, Kenya
  • 2018
  • Ingår i: Carbon Balance and Management. - : Springer Science and Business Media LLC. - 1750-0680. ; 13
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Pasture enclosures play an important role in rehabilitating the degraded soils and vegetation, and may also influence the emission of key greenhouse gasses (GHGs) from the soil. However, no study in East Africa and in Kenya has conducted direct measurements of GHG fluxes following the restoration of degraded communal grazing lands through the establishment of pasture enclosures. A field experiment was conducted in northwestern Kenya to measure the emission of CO2,CH4 and N2O from soil under two pasture restoration systems; grazing dominated enclosure (CGE) and contractual grazing enclosure (CGE), and in the adjacent open grazing rangeland (OGR) as control. Herbaceous vegetation cover, biomass production, and surface (0-10 cm) soil organic carbon (SOC) were also assessed to determine their relationship with the GHG flux rate.Results: Vegetation cover was higher enclosure systems and ranged from 20.7% in OGR to 40.2% in GDE while aboveground biomass increased from 72.0 kg DM ha(-1) in OGR to 483.1 and 560.4 kg DM ha(-1) in CGE and GDE respectively. The SOC concentration in GDE and CGE increased by an average of 27% relative to OGR and ranged between 4.4 g kg(-1) and 6.6 g kg(-1). The mean emission rates across the grazing systems were 18.6 mu g N m(-2 )h(-1) 50.1 mu g C m(-2) h(-1) and 199.7 mg C m(-2) h(-1) for N2O, CH4, and CO2, respectively. Soil CO2 emission was considerably higher in GDE and CGE systems than in OGR (P< 0.001). However, non-significantly higher CH4 and N2O emissions were observed in GDE and CGE compared to OGR (P = 0.33 and 0.53 for CH4 and N2O, respectively). Soil moisture exhibited a significant positive relationship with CO2, CH4, and N2O, implying that it is the key factor influencing the flux rate of GHGs in the area.Conclusions: The results demonstrated that the establishment of enclosures in tropical rangelands is a valuable intervention for improving pasture production and restoration of surface soil properties. However, a long-term study is required to evaluate the patterns in annual CO2,N2O, CH4 fluxes from soils and determine the ecosystem carbon balance across the pastoral landscape.
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38.
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39.
  • Nyberg, Gert, et al. (författare)
  • Respiration from C-3 plant green manure added to a C-4 plant carbon dominated soil
  • 2000
  • Ingår i: Plant and Soil. - 0032-079X .- 1573-5036. ; 218:1-2, s. 83-89
  • Tidskriftsartikel (refereegranskat)abstract
    • Application of tree leaves (C3 plants) on maize (Zea mays L.) (C4 plant) fields is an agroforestry management technology to restore or maintain soil fertility. The rate at which the tree leaves decompose is crucial for the nutrient supply to the crop. We studied the in situ decomposition of Sesbania sesban (L.) Merr. leaves or C3 sugar for 4 – 8 days after application to a maize field in Kenya. By using the difference of around 10‰ in natural abundance of 13C between the endogenous soil C (mainly C4) and the applied C (C3), we could calculate the contributions of the two C sources to soil respiration. The δ13C value of the basal respiration was from –15.9 to –16.7‰. The microbial response to the additions of leaves and sugar to this tropical soil was immediate. Application of sesbania leaves gave an initial peak in respiration rates that lasted from one to less than 6 days, after which it levelled off and remained about 2 – 3 times higher (230–270 mg C m-2 h-1) than the control respiration rates throughout the rest of the experiment (5 – 8 days). In the sugar treatment, there was no initial peak in respiration rate. The respiration rate was 170 mg C m-2 h-1 after 4 days. At the end of the experiments, after 4–8 days, as much as 14–17% of the added C had been respired and about 60% of the total respiration was from the added sesbania leaves or C3 sugar. This non-destructive method allows repeated measurements of the actual rate of C mineralisation and facilitates decomposition studies with high temporal resolution in the field.
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40.
  • Nyberg, Gert, et al. (författare)
  • Short-term patterns of carbon and nitrogen mineralisation in a fallow field amended with green manures from agroforestry trees
  • 2002
  • Ingår i: Biology and Fertility of Soils. - : Springer Science and Business Media LLC. - 0178-2762 .- 1432-0789. ; 36:1, s. 18-25
  • Tidskriftsartikel (refereegranskat)abstract
    • The mineralisation of green manure from agroforestry trees was monitored with the objective to compare the temporal dynamics of mineralisation of litter from different species. Green manures from five agroforestry tree species were used on a fallow field during the long rainy season of 1997 (March–August) and from two species in the following short rainy season (September–January) in western Kenya. Different methods, i.e. measurements of isotopic ratios of C in respired CO2 and of soil organic matter (SOM) fractions, soil inorganic N and mass loss from litterbags, were used in the field to study decomposition and C and N mineralisation. Soil respiration, with the separation of added C from old soil C by using the isotopic ratio of 13C/12C in the respired CO2, correlated well with extractable NH4 + in the soil. Mineralisation was high and very rapid from residues of Sesbania sesban of high quality [e.g. low ratio of (polyphenol+lignin)/N] and low and slow from low quality residues of Grevillea robusta. Ten days after application, 37% and 8% of the added C had been respired from Sesbania and Grevillea, respectively. Apparently, as much as 70–90% of the added C was respired in 40 days from high quality green manure. Weight losses of around 80%, from high quality residues in litterbags, also indicate substantial C losses and that a build-up of SOM is unlikely. For immediate effects on soil fertility, application of high quality green manure may, however, be a viable management option. To achieve synchrony with crop demand, caution is needed in management as large amounts of N are mineralised within a few days after application.
  •  
41.
  • Nyberg, Gert, et al. (författare)
  • Soil property changes over a 120-yr chronosequence from forest to agriculture in western Kenya
  • 2012
  • Ingår i: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 16, s. 2085-2094
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract. Much of the native forest in the highlands of western Kenya has been converted to agricultural land in order to feed the growing population, and more land is being cleared. In tropical Africa, this land use change results in progressive soil degradation, as the period of cultivation increases. Both rates and variation in infiltration, soil carbon concentration and other soil parameters are influenced by management within agricultural systems, but they have rarely been well documented in East Africa. We constructed a chronosequence for an area of western Kenya, using two native forest sites and six fields that had been converted to agriculture for up to 119 yr. We assessed changes in infiltrability (the steady-state infiltration rate), bulk density, proportion of macro- and microaggregates in soil, soil C and N concentrations, as well as the isotopic signature of soil C (δ13C), along the 119-yr chronosequence of conversion from natural forest to agriculture. Infiltration, soil C and N decreased within 40 yr after conversion, while bulk density increased. Median infiltration rates fell to about 15% of the initial values in the forest, and C and N concentrations dropped to around 60%, whilst the bulk density increased by 50%. Despite high spatial variability, these parameters have correlated well with time since conversion and with each other.
  •  
42.
  • Ouattara, Korodjouma, et al. (författare)
  • Effect of land degradation on carbon and nitrogen pools in two soil types of a semi-arid landscape in West Africa
  • 2015
  • Ingår i: Geoderma. - : Elsevier BV. - 0016-7061 .- 1872-6259. ; 241-242, s. 330-338
  • Tidskriftsartikel (refereegranskat)abstract
    • To determine the resilience of soil organic C and N pools during land degradation processes in a semi-arid landscape of West Africa, we compared the magnitude of soil organic C and N differences in bulk soil and aggregate fractions between contrasting types of land cover (degraded land and native land cover) and soil (Luvisols and Cambisols). We analyzed the following soil key indicators: CEC, soil respiration, C and N contents, and δ13C and δ15N signatures of soil organic C. The average CO2respired from native land cover was at least 82% higher than its value from degraded land cover and was significantly higher in Luvisols than in Cambisols. Likewise, the soil organic C and N contents in bulk soil were significantly affected by land cover and soil contrasts. The average C loss in bulk soil from degraded land cover was equivalent to 49% in Cambisols and 54% in Luvisols. In both soil types, all aggregate fractions were sensitive to land degradation processes and the C loss decreased from macroaggregates to the clay+silt fraction. Compared to the native land cover, organic C loss from the macroaggregates in degraded land cover was 92% and 84%, respectively, in Cambisols and Luvisols. The soil type affected significantly the C content only in the clay+silt fraction. The C/N ratio of finer fractions (microaggregates and clay+silt) was significantly higher in degraded land cover than in native land cover, indicating greater losses of N than C during land degradation processes. The differences of δ13C signatures throughout C pools between the two types of land cover suggest a relative dominance of C3derived C in macroaggregates and C4derived C in the clay+silt fraction in the degraded lands. The reduction of soil respiration and the rapid N loss in degraded land cover slowed down the humification processes of C3plant derived materials which were effectively dominant in macroaggregates.
  •  
43.
  • Ruvuga, Peter, et al. (författare)
  • Evaluation of rangeland condition in miombo woodlands in eastern Tanzania in relation to season and distance from settlements
  • 2021
  • Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 290
  • Tidskriftsartikel (refereegranskat)abstract
    • Miombo woodlands sustainability in east and south-central Africa is threatened by human activities, including overgrazing. This study investigated seasonal variations in rangeland condition in three grazed areas in miombo woodlands in eastern Tanzania. Transect lines were established across the grazing areas, sampling points were identified and marked at every 10% of the length of transect line. Sampling points were categorised in different distances with respect to settlement. The line intercept method was used to collect data on vegetation cover and forage distribution, while herbaceous forage biomass was estimated using a disc pasture meter. A total of 118 different plant species were observed and grasses comprised 40.6% of all herbaceous species. Bothriochloa pertusa, Cynodon plectostachyus, Hyparrhenia rufa and Urochloa mosambicensis grass species dominated miombo grazed areas in various seasons and distances. These perennial grass species are desirable and indicated moderate grazing activities in miombo. Season affected grass cover, herbaceous forage biomass and nutritional composition. Grass cover and forage biomass were at the lowest during late dry season while forage nutritional quality was best during early dry season. Distance from settlement had no effect on grass cover and herbaceous forage biomass. Rangeland condition was generally fair, livestock stocking rate in continuously grazed drylands should be set at the lowest monthly forage biomass in order to ensure grazing land sustainability.
  •  
44.
  • Ruvuga, Peter, et al. (författare)
  • Indigenous Rangeland and Livestock Management Among Pastoralists and Agro-pastoralists in Miombo Woodlands, Eastern Tanzania
  • 2020
  • Ingår i: Rangeland Ecology and Management. - : Elsevier BV. - 1550-7424 .- 1551-5028. ; 73, s. 313-320
  • Tidskriftsartikel (refereegranskat)abstract
    • Indigenous rangeland management practices, forage quality and availability, and livestock production by pastoralists and agro-pastoralists in miombo woodlands were investigated in a study conducted in Kilosa district, Tanzania. The study methods comprised household interviews, key informant and focus group discussions, and forage laboratory analyses. Preferred forage species and indigenous rangeland and livestock management practices among pastoral and agro-pastoral communities in miombo woodlands were identified, and the nutrient content of the forages was determined. In general, rangeland management in the study area faces challenges such as unclear or disputed land tenure regime and lack of technical knowledge. Moreover, the nutritional value of some native forage species identified in miombo was found to be too low to meet the nutrient requirements of livestock. Livestock in miombo contribute greatly to household livelihoods and food security, but forage scarcity was identified as a limiting factor. Overall, it was concluded that rangeland improvement practices are poor or nonexistent in allocated grazing areas in Kilosa's miombo woodlands. (C) 2019 The Society for Range Management. Published by Elsevier Inc. All rights reserved.
  •  
45.
  • Stage, Jesper, et al. (författare)
  • Project: Restoration of forests, carbon and livelihoods: REDD+ and the economics of miombo land use
  • 2016
  • Annan publikation (populärvet., debatt m.m.)abstract
    • This application brings together a multidisciplinary team to study the opportunities for, and implications of, better management of miombo forest landscapes in Tanzania. To develop and improve miombo production systemsthere is need for both broadened and deepened understanding of present land use, forest ecology, forest products economy, and related social and economic structures on process scale and up-scaled in the landscape. Tightly coupled to this is the analysis on the appropriateness and sustainability of different C-sequestration and C-trade mechanisms and land use forest management in relation to adaptation to climate vulnerability. Tanzania is chosen because of significantly heightened interest in the forest sector, but the suggested research will be applicable for the larger miombo area as well as for dry land Africa at large.
  •  
46.
  • Sundberg, Cecilia, et al. (författare)
  • Biochar from cookstoves reduces greenhouse gas emissions from smallholder farms in Africa
  • 2020
  • Ingår i: Mitigation and Adaptation Strategies for Global Change. - : Springer Nature. - 1381-2386 .- 1573-1596. ; 25:6, s. 953-967
  • Tidskriftsartikel (refereegranskat)abstract
    • Biochar produced in cookstoves has the potential to contribute to negative carbon emissions through sequestration of biomass carbon while also providing other benefits for sustainable development, including provision of clean renewable energy and increased yields in tropical agriculture. The aim of the reported research was to estimate effects on food production, household energy access and life cycle climate impact from introduction of biochar-producing cookstoves on smallholder farms in Kenya. Participatory research on biochar production and use was undertaken with 150 Kenyan smallholder farming households. Gasifier cookstove functionality, fuel efficiency and emissions were measured, as well as biochar effects on agricultural yields after application to soil. Cookstoves provided benefits through reduced smoke, fuel wood savings and char production, but challenges were found related to labour for fuel preparation, lighting and refilling. On-farm trials with varying rates of biochar inputs, in combination with and without mineral fertilizers, have led to a sustained increase of maize yields following one-time application. The climate impact in a life cycle perspective was considerably lower for the system with cookstove production of biochar and use of biochar in agriculture than for current cooking practices. Climate benefits from biochar production and use are thus possible on smallholder farms in sub-Saharan Africa, through reduced use of biomass in cooking, reduced emissions of products of incomplete combustion and sequestration of stable biochar carbon in soils. Biochar-producing cookstoves can be implemented as a climate change mitigation method in rural sub-Saharan Africa. Successful implementation will require changes in cooking systems including fuel supply, as well as farming systems, which, in turn, requires an understanding of local socio-cultural conditions, including power relations and gender aspects.
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