洱海西部雨季地表径流氮磷污染特征及受土地利用类型的影响

目的降低烟田氮、磷养分流失,保护湖泊流域水质的同时保障烟叶的优质生产。方法采用田间原位实时收集水样方法,在弥渡(洱海流域)和澄江(抚仙湖流域)研究不同基追比例(100∶0;70∶30和30∶70)对氮、磷养分流失和烟叶经济性状的影响。结果不同基追比例的径流水流失总量和渗漏水流失总量差异不显著(P>0.05)。基追比30∶70处理的径流水和渗漏水氮流失量以及磷流失量低于基追比100∶0和70∶30处理,径流水中氮流失量分别减少9.16%~66.44%和3.90%~67.77%,磷流失量分别减少6.16%~9.36%和2.25%~17.45%;渗漏水中氮流失量分别减少0.56%~67.54%和21.59%~26.89%,磷流失量分别减少4.20%~33.33%和10.08%~20.00%。基追比30∶70处理的产量和产值高于基追比100∶0处理和70∶30处理,产量分别增加24.08%~24.18%和1.44~2.26%,产值分别增加8.81%~39.04%和2.56~5.55%。结论云南高原湖泊流域采用基追比30∶70的施用方式在降低面源污染风险的同时能保障湖泊流域烟叶的优质生产。     

循环型农业清洁流域建设——以柘皋河流域为例

为在流域尺度下构建全面系统的面源污染防控体系,以安徽省巢湖流域内一个典型的农业流域柘皋河流域作为案例,调查该流域种植制度、养殖模式、农村生活等数据,分析其面源污染特征,基于水环境容量计算柘皋河流域种植源氮磷减排潜力,在借鉴生态清洁小流域建设思路的基础上,提出循环型农业清洁流域建设,并从环境效益和技术应用两方面构建评价体...     

气域及其在林业上的应用展望

介绍了气域的概念、应用及气域范围的确定方法,比较了气域与流域在内涵与应用上的相互关系,并以城市森林与防风固沙林为例,对气域在林业上的应用进行了探讨。     

利用遥感和地理信息系统技术通过分析土壤性质预测洪水灾害: 以泰国Chiang Mai省Mae Rim分水岭为例

Physiography and soil in Mae Rim watershed,Chiang Mai Province,Thailand were investigated by using aerial photographs and satellite image in conjunction with field work,and soil infiltration rate and soil shear resistance were measured in field. Many factors affecting runoff were analyzed usig the Integrated Land and Water Informaiton System(ILWIS).As a result,a model determining flood hazar was set up.Three mps including runoff curve number map,runoff coefficent map,and flood inumdation map were created,In addition,the time of concentration was predicted.     

豫西黄土丘陵区架子河小流域土地资源开发利用研究

通过对土地构成要素的分析,根据土地质量的特点和差异性,对豫西黄土丘陵区架子河小流域的土地资源进行了系统分析评价。根据该区特点,主要选择了坡度,土层厚度,砾石或砂姜含量和灌溉条件４项指标,进行了土地分级,根据土地利用现状和生产实际中存在的问题,提出了各级地的合理开发利用方向和途径。     

试论吉兰泰盐湖的发育与资源保护问题

位于包头－吉兰泰断陷盆地西南部的吉兰泰盐湖,其发育过程大体经历了外泄湖、内陆湖与盐湖三个阶段。目前盐湖已发育为干盐湖,并有快速发展为沙下湖之趋势。湖盐开采中出现的晶间卤水水位下降、流沙入湖等问题既是盐湖演化的必然结果,又与开发中轻视资源保护有关。解决这些问题的办法是在顺应盐湖演化规律的基础上采取人工措施,延缓盐湖演化的速度,在盐湖演化为沙下湖之前完成全部采盐任务。     

小流域土地评价模型应用研究

通过以江西省赣县桃源河小流域宜农、宜林、不宜地为评价目标,系统地论述了小流域土地评价模型在赣县桃源河小流域土地评价中应用的作用、过程和方法步骤,并对模型所计算的结果进行了详细分析     

小流域淤地坝坝系分布设计方案的优化研究

本文针对小流域淤地坝坝系布设方案的优化问题,从坝址、坝系密度、坝高、建坝顺序,建坝时间间隔等几个方面进行了比选,并由此道选出最优布设方案。为流域淤地坝坝系的合理布设,提供了科学的理论依据与精确的定量分析方法。     

Farmland degradation in the mountains of Nepal: a study of watersheds ‘with’ and ‘without’ external intervention

Amidst growing concerns about farmlands conservation, this paper examines the status of farmlands in two mountain watersheds ‘with’ and ‘without’ external intervention, located in the western hills of Nepal. Information was obtained from a household survey and group discussions conducted during April to September 1999. The severity of soil erosion from farmers' perspectives, density of landslides, soil nutrient balance and change in crop yield have been adopted as indicators of the status of the land. Results of the analysis indicate that land resources in both watersheds are undergoing degradation, though the causes and extent of degradation vary from one type of land to another. Upland crop terraces, locally called bari, are undergoing degradation most seriously under the combined influence of severe soil erosion, landslide and the depletion of soil nutrients. In particular, soil erosion has severely affected nearly half of the upland crop terraces in both watersheds due to a number of natural and anthropogenic factors ranging from weak geological structure to arable agriculture. Landslide and nutrient depletion have affected all types of farmlands except homesteads in both watersheds. Overall, the extent and intensity of land degradation is relatively high in the non‐project area, as farmers were not provided with necessary technical and financial support. A broad strategy has been outlined for effective conservation of farmlands. Copyright © 2002 John Wiley & Sons, Ltd.     

三峡水库小江流域消落区植物多样性研究

为了解三峡水库运行初期消落区的植被状况,2009年5月、7月和9月对小江流域消落区高程150、160和170m处植物的种类组成、生物量和多样性等特征进行了调查与分析。结果表明,小江流域消落区维管束植物共有140种,隶属于38科113属,以草本植物或旱生植物为主。群落优势种主要有香附、苍耳、小白酒草、狗牙根等18种。生物量均值999.9g/m2,变幅140.7～2055.6g/m2;烘干重均值310.7g/m2,变幅为26.5～932.6g/m2。植物多样性Margalef指数、Shannon-Wiener指数、Simpson指数和Pielou均匀度指数等均在5月最小,7月最大,9月略下降,在高程150m处最小,160m处最大,170m处次之。并对小江流域消落区植物的演替趋势、生态恢复、影响因素和利用前景进行了初步探讨。