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土地利用对卢旺达基伍湖的潜在影响分析
MUPENZI Christophe
Subtype博士
Thesis Advisor李兰海
2018-06-05
Degree Grantor中国科学院大学
Place of Conferral新疆乌鲁木齐
Degree Discipline理学博士
Keyword富营养化 生计多样性 理化性质 河流污染指数 水质 Eutrophication Livelihood diversity Physical and chemical properties River pollution index Water quality
Abstract湖泊富营养化是一个关键的环境问题,它依赖于流域内养分的可获得性以及它们向湖泊移动的可能性。流域内养分的移动在很大程度上受土地利用变化的影响。本研究通过分析土地利用的潜在影响,以期找出卢旺达基伍湖外部营养物的来源。研究的主要工作有:分析入湖河流水质的空间分布和湖泊富营养化状况与相邻土地利用类型的关系,比较和评估土地利用类型对土壤剖面理化性质的影响,以及评估生计多样性对土地利用变化的影响。利用国家卫生基金会水质指数(NSFWQI)和河流污染指数(RPI)对排入湖泊的河流水质进行了空间分析。研究表明水质与临近土地利用/覆被和地形之间存在关系。17.5%的未污染的河流位于林地占主导的地区,26%的中度污染受到综合土地利用类型以及坡度和热带降雨的影响。此外,56.5%的河流被农田占优势的土地所包围。通过分析湖泊养分状况、有机物指标、盐度和浮游植物丰度指标等,研究了不同季节变化下湖泊富营养化与流域土地利用之间的关系。研究表明,雨季湖泊富营养化与土地利用方式之间的相关度比旱季更高。无论雨季还是旱季,与其它土地利用类型相比,农田与水质具有更高的相关性。通过引入土地利用的地形特征分析,其结果表明:在坡度大的地区,土地利用对湖泊富营养化的影响比小坡度地区更大。在不同土地利用类型对土壤理化性质影响方面,本研究分析了覆膜咖啡(MC)、间作咖啡(IC)和未覆膜咖啡(UC)三种咖啡农业系统下不同土地利用类型的土壤理化性质。结果表明,表土层和亚土层的土壤有机碳含量、Ca2+、Mg2+、Na+、K+、N、P 和 pH值指标均表现为 MC> IC> UC,土壤容重(BD)不仅呈现出相反的顺序(MC < IC
Other AbstractNutrient loading to lakes as a key environmental issue, which relies upon availability of nutrientsin a watershed as well as their possibility for movement to a lake, must be tended for a bettercomprehension of the multifarious connection between land use (LU) and water quality. Thisresearch analyzed the potential impacts of LU in order to point out the sources of externalnutrients to the Lake Kivu in Rwanda. It specifically focused to assess the spatial distribution ofrivers water quality draining into the lake, to relate lake eutrophication status with adjacent LUtypes, to evaluate and compare the impacts of LU types to physicochemical properties of soilprofiles and finally to assess perceived impact of LU change issued by livelihood diversification. Water quality of rivers draining into the lake has been spatially analyzed by using the NationalSanitation Foundation Water Quality Index (NSFWQI) and River Pollution Index (RPI). It hasbeen found the existence of relationship between rivers water quality, adjacent land use/ landcover (LULC) and topography. Thus, 17.5 % of negligibly polluted rivers were located in areasdominated by forestland while 26 % of moderately polluted were influenced by combined LUtypes as well as slope and tropical rainfall. Moreover, 56.5 % of rivers were surrounded bydominance of farmland. The link between lake eutrophication and watershed LU in differentseasonal variations was studied by analyzing indicators of nutrient conditions, indicators oforganic matter, indicators of salinity and phytoplankton abundance indicators in the lake. It hasbeen proved that the link between lake eutrophication and LU patterns were stronger in rainyseasons than that in dry seasons. In both rainy and dry seasons; farmland, compared to other LUtypes, manifested a sturdier relationship with water quality variables. As topographic features ofLU were engaged for more analysis of these relationships, the results proved that slope disparityappeared in the multifaceted connection, and LU types in sharper slopes normally had a sturdierinfluence on lake eutrophication than those in flatter ones. Physicochemical properties status of soil under different LU types have been analyzed in threecoffee farming systems including mulched coffee (MC), intercropped coffee (IC) and un- mulched coffee (UC). Results showed that, contents of soil organic carbon (SOC), Ca2+, Mg2+, Na+, K+, N, P and pH followed the trend: MC > IC > UC in both topsoil and subsoil. Bulkdensity (BD) appeared in opposite trends than other soil properties not only in reverse order (MC< IC < UC) but also by increasing as soil depths increased under all farming systems. Correlationbetween BD and soil depths (0.90 < 0.95 < 1) in MC, IC and UC respectively has been observedinferring negative correlation between bulk density and soil organic carbon (-0.94 > -0.97 > - 0.99). Finally, the perceived impact of LU change supports the necessity to includeconsideration of livelihood diversification strategies in the wider evaluation of naturalenvironment. It has been proved that human population growth and soil fertility degradationwere perceived as relevant issues, not yet emergencies which explain radical action to confinetheir autonomy or conventional practices. It is therefore, evidence from the above results that this study supports the incorporation oflandscape analysis in order to comprehend the multifaceted nature of external nutrients loadingto the lake. It also supports the proposal that water quality can be enhanced by better LUmanagement like appropriate methods for conserving soil and water with special attention tofarmland. The utility of this research to screen soil quality dynamics and foreseeing LU variationimpacts on soil quality warrants for further investigations.
Subject Area自然地理学
Language英语
Document Type学位论文
Identifierhttp://ir.xjlas.org/handle/365004/14922
Collection研究系统_荒漠环境研究室
Affiliation中国科学院新疆生态与地理研究所
First Author Affilication中国科学院新疆生态与地理研究所
Recommended Citation
GB/T 7714
MUPENZI Christophe. 土地利用对卢旺达基伍湖的潜在影响分析[D]. 新疆乌鲁木齐. 中国科学院大学,2018.
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