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Land-use System (land-use + system)
Selected AbstractsEcological gradients as a framework for analysis of land-use change in East AfricaAFRICAN JOURNAL OF ECOLOGY, Issue 2009A. E. Majule Abstract This paper discusses the ecological gradient as an organizing framework to assist understanding the complex interactions between societal and ecological processes underlying land-use change in East Africa. Detailed case studies on the gradients of the slopes of Mt Kilimanjaro, Kenya show how land-use change is responsive to the dynamics of both local and external driving forces. The study has shown that the distinct ecological conditions at the extremities of gradients are associated with specific land uses which may be different within livelihood systems such as for wet and dry season grazing. Access to water for cultivation, domestic use, livestock and wildlife is critical in determining the nature and distribution of livelihood systems. Land-use systems interact across the different ecological zones of the gradients characterized by vigorous spatial, cultural and economic interactions. Sometime conflicts occur between or within land-use/livelihood systems. There is strong evidence that the areas of higher economic potential remain advantaged compared with areas lower on the gradient. The ecological characteristics have been found to influence human activities and distribution. Interactions between societies are important in terms of trade, social relations and access to resources. [source] Policies, Interventions and Institutional Change in Pastoral Resource Management in Borana, Southern EthiopiaDEVELOPMENT POLICY REVIEW, Issue 4 2004Abdul B. Kamara The Borana rangelands of Southern Ethiopia are characterised by extensive livestock production under a communal land-use system that has evolved in response to variable rainfall and uncertain production conditions. However, the last two decades have witnessed an increasing privatisation of rangelands for crop production and private grazing. The results of a quantitative assessment are used to develop a framework for assessing the drivers of change and their long-term implications. It is concluded that certain national policies have resulted in conflicts of authority between traditional and formal systems, creating an avenue for spontaneous enclosures, associated conflicts and decreasing human welfare. [source] Soilscape and land-use evolution related to drift sand movements since the bronze age in Eastern Jutland, DenmarkGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 2 2007Jari Hinsch Mikkelsen Quarry faces several kilometers long in the Glesborg area in Denmark show that Bronze Age farmers used a sustainable land-use system. Despite nutrient-poor soils, the Glesborg area was under a rotation system in which cropland alternated with grassland. Soil fertility was improved by the addition of household waste and probably also by locally obtained inorganic fertilizer. The soil surface was very stable, and local drift sand movement was limited. Toward the end of the Bronze Age, the landscape changed dramatically with the arrival of overwhelming amounts of drift sand, and farmsteads were abandoned. Subsequent land use on these poor fine sandy soils was no longer capable of maintaining a stable soil surface, and frequent erosion/sedimentation events of more local importance took place. The post-Bronze Age landscape may have been mainly a shifting mosaic of heathland with some temporary arable fields and deflation/accumulation areas. This landscape persisted up to about 200 years ago, when afforestation programs started. © 2007 Wiley Periodicals, Inc. [source] RUNOFF PRODUCTION AND EROSION PROCESSES ON A DEHESA IN WESTERN SPAIN,GEOGRAPHICAL REVIEW, Issue 3 2002ANTONIO CEBALLOS ABSTRACT. Runoff generation and soil erosion were investigated at the Guadalperalón experimental watershed (western Spain), within the land-use system known as dehesa, or open, managed evergreen forests. Season and type of surface were found to control runoff and soil-loss rates. Five soil units were selected as representative of surface types found in the study area: hillslope grass, bottom grass, tree cover, sheep trails, and shrub cover. Measurements were made in various conditions with simulated rainfall to gain an idea of the annual variation in runoff and soil loss. Important seasonal differences were noted due to surface cover and moisture content of soil, but erosion rates were determined primarily by runoff. Surfaces covered with grass and shrubs always showed less erosion; surfaces covered with holm oaks showed higher runoff rates, due to the hydrophobic character of the soils. Concentrations of runoff sediment during the simulations confirmed that erosion rates at the study site depended directly on the sediment available on the soil surface. [source] Contribution of N2O to the greenhouse gas balance of first-generation biofuelsGLOBAL CHANGE BIOLOGY, Issue 1 2009EDWARD M. W. SMEETS Abstract In this study, we analyze the impact of fertilizer- and manure-induced N2O emissions due to energy crop production on the reduction of greenhouse gas (GHG) emissions when conventional transportation fuels are replaced by first-generation biofuels (also taking account of other GHG emissions during the entire life cycle). We calculate the nitrous oxide (N2O) emissions by applying a statistical model that uses spatial data on climate and soil. For the land use that is assumed to be replaced by energy crop production (the ,reference land-use system'), we explore a variety of options, the most important of which are cropland for food production, grassland, and natural vegetation. Calculations are also done in the case that emissions due to energy crop production are fully additional and thus no reference is considered. The results are combined with data on other emissions due to biofuels production that are derived from existing studies, resulting in total GHG emission reduction potentials for major biofuels compared with conventional fuels. The results show that N2O emissions can have an important impact on the overall GHG balance of biofuels, though there are large uncertainties. The most important ones are those in the statistical model and the GHG emissions not related to land use. Ethanol produced from sugar cane and sugar beet are relatively robust GHG savers: these biofuels change the GHG emissions by ,103% to ,60% (sugar cane) and ,58% to ,17% (sugar beet), compared with conventional transportation fuels and depending on the reference land-use system that is considered. The use of diesel from palm fruit also results in a relatively constant and substantial change of the GHG emissions by ,75% to ,39%. For corn and wheat ethanol, the figures are ,38% to 11% and ,107% to 53%, respectively. Rapeseed diesel changes the GHG emissions by ,81% to 72% and soybean diesel by ,111% to 44%. Optimized crop management, which involves the use of state-of-the-art agricultural technologies combined with an optimized fertilization regime and the use of nitrification inhibitors, can reduce N2O emissions substantially and change the GHG emissions by up to ,135 percent points (pp) compared with conventional management. However, the uncertainties in the statistical N2O emission model and in the data on non-land-use GHG emissions due to biofuels production are large; they can change the GHG emission reduction by between ,152 and 87 pp. [source] Ecological implications of Fulbe pastoralism in southwestern NigeriaLAND DEGRADATION AND DEVELOPMENT, Issue 5 2003Akin M. Omotayo Abstract The study used a combination of ethno-social surveys and Geographical Information Systems (GIS) to assess 651 pastoral households and their land use under agropastoral production systems in Ogun State, Nigeria. Yields of arable crops on agropastoralists' fields were generally low. Livestock productivity was similar on all parameters to levels in comparable contexts elsewhere across the West African subregion, but generally below possible potentials and on-farm research findings. Pastoral households' activities presently influence between 221,km2 and 523,km2 of land in Ogun State. Pastoral grazing orbits extended beyond administrative boundaries, causing potential conflicts between local crop farmers and agropatoralists. Much of the land-cover has been altered considerably around the areas of pastoral household settlements compared with the situation 20 years ago. It was concluded that a form of intervention was needed that would guarantee sustainability of the land-use system. Copyright © 2003 John Wiley & Sons, Ltd. [source] Contribution of N2O to the greenhouse gas balance of first-generation biofuelsGLOBAL CHANGE BIOLOGY, Issue 1 2009EDWARD M. W. SMEETS Abstract In this study, we analyze the impact of fertilizer- and manure-induced N2O emissions due to energy crop production on the reduction of greenhouse gas (GHG) emissions when conventional transportation fuels are replaced by first-generation biofuels (also taking account of other GHG emissions during the entire life cycle). We calculate the nitrous oxide (N2O) emissions by applying a statistical model that uses spatial data on climate and soil. For the land use that is assumed to be replaced by energy crop production (the ,reference land-use system'), we explore a variety of options, the most important of which are cropland for food production, grassland, and natural vegetation. Calculations are also done in the case that emissions due to energy crop production are fully additional and thus no reference is considered. The results are combined with data on other emissions due to biofuels production that are derived from existing studies, resulting in total GHG emission reduction potentials for major biofuels compared with conventional fuels. The results show that N2O emissions can have an important impact on the overall GHG balance of biofuels, though there are large uncertainties. The most important ones are those in the statistical model and the GHG emissions not related to land use. Ethanol produced from sugar cane and sugar beet are relatively robust GHG savers: these biofuels change the GHG emissions by ,103% to ,60% (sugar cane) and ,58% to ,17% (sugar beet), compared with conventional transportation fuels and depending on the reference land-use system that is considered. The use of diesel from palm fruit also results in a relatively constant and substantial change of the GHG emissions by ,75% to ,39%. For corn and wheat ethanol, the figures are ,38% to 11% and ,107% to 53%, respectively. Rapeseed diesel changes the GHG emissions by ,81% to 72% and soybean diesel by ,111% to 44%. Optimized crop management, which involves the use of state-of-the-art agricultural technologies combined with an optimized fertilization regime and the use of nitrification inhibitors, can reduce N2O emissions substantially and change the GHG emissions by up to ,135 percent points (pp) compared with conventional management. However, the uncertainties in the statistical N2O emission model and in the data on non-land-use GHG emissions due to biofuels production are large; they can change the GHG emission reduction by between ,152 and 87 pp. [source] Bush encroachment under three contrasting land-use practices in a mesic South African savannaAFRICAN JOURNAL OF ECOLOGY, Issue 2009B. J. Wigley Abstract This study determined the effects of land-use practice had on the rate and extent of bush encroachment in a mesic savanna in KwaZulu-Natal, South Africa. Changes in woody cover were measured for 1 km2 sites in areas under communal, commercial and conservation land-use systems for the period between 1937 and 2000. Land users from each area were interviewed to gain the histories of each area and to determine how the changes in woody cover had impacted them and whether anything was being done to counteract the spread of trees and shrubs on their land. Bush encroachment occurred across all three of the land-use types in the 67-year period between 1937 and 2000. The results showed that land-use practice had enormous impacts on the process of bush encroachment. The communal site showed a decrease in grass (21%) and tree (5%) cover and an increase in shrub cover (13%). At the commercial site, there was a considerable decrease in grass cover (46%) and moderate increase in shrub cover (10%) and a massive increase in tree cover (36%). The area under conservation showed a substantial decrease in grass cover (47%), a slight decrease in shrub cover (19%) and a massive increase in tree cover (66%). The perceived causes of these changes were fairly similar amongst the different land users. The changes were mostly not perceived to be a problem for the communal land users. The main advantages mentioned were increased woody resources for building and firewood and increased browse availability. The commercial and conservation land users perceived the changes to have significant negative connotations including the loss of grazing land and biodiversity and secondary invasion of encroached areas by alien plant species. Despite these perceptions, very little has been done to combat bush encroachment in the commercial and conservation land use systems. [source] The coming of age of agroforestryJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2007PK Ramachandran Nair The success of modern agricultural and forestry production can be largely attributed to monoculture systems using a few select species. In the drive for maximizing yield and profit, the age-old tradition of using combined farming systems was essentially avoided and in some cases this has resulted in environmental problems such as land and water degradation and increased land clearing. During the last 30 years, however, the positive benefits of agroforestry to the producer and the environment have been increasingly recognized. Combining trees and crops in spatial or temporal arrangements has been shown to improve food and nutritional security and mitigate environmental degradation, offering a sustainable alternative to monoculture production. By providing supportive and complimentary roles with a flexible approach, agroforestry can offer specific social and environmental benefits across a range of landscapes and economies. More research and effort is needed to explore the full potential of agroforestry applications and to fuel awareness. As the plethora of benefits of agroforestry are realized, modern land-use systems are evolving towards a more sustainable and holistic approach to land management. Copyright © 2007 Society of Chemical Industry [source] Options for increasing carbon sequestration in West African soils: an exploratory study with special focus on SenegalLAND DEGRADATION AND DEVELOPMENT, Issue 2 2001N. H. Batjes Abstract The organic matter content of many soils in West Africa has been depleted due to overgrazing, agricultural mismanagement, deforestation and overexploitation of the natural resources. Degraded agro(eco)systems can be managed to increase carbon sinks in vegetation and soil, and to reduce carbon emissions to the atmosphere. The capacity for sequestering carbon will increase as annual precipitation increases, and generally as mean temperature decreases, provided the soil and terrain conditions are not limiting for crop (biomass) growth. The agroecological suitability of three pilot sites, proposed for soil carbon sequestration projects in Senegal, is assessed and the feasibility of various management options to increase organic carbon levels in the soil is discussed. For the future, a Land Resources Information System should be developed to consider detailed data on climate, soil and terrain conditions, status of soil degradation, and land-use systems for West Africa. Upon its linkage to a dynamic soil carbon model and a socio-economic module, such an integrated system can be used to assess the ecotechnological and socio-economic potential for carbon sequestration projects in the context of the Clean Development Mechanism (CDM) proposed under article 12 of the Kyoto Protocol to the United Nations Framework Convention on Climate Change. If adopted, this mechanism could confer funds to West African countries for the sustainable use and conservation of their natural resources, thereby providing economic, environmental and societal benefits for local populations, while simultaneously contributing to climate change mitigation. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||||||||