阿拉善额济纳地区公路盐胀病害成因分析

阿拉善额济纳地区位于内蒙古自治区西北寒旱区,其境内哈温段与达来呼布至策克口岸省道S315部分路段在路面横向上不间断出现类似"天然减速带"的病害现象,严重处路面横向凸起高度约10cm,对行车安全构成极大危险.对病害路段基层、路基不同深度试样及路基坡面试样的化学成分进行了分析.结果表明,试样中氯离子质量分数与硫酸根离子质量分数之比小于0.3,硫酸盐盐渍化明显,为典型的硫酸盐渍土,盐渍化程度与路面横向凸起幅度相吻合,凸起幅度愈大,平均含盐量愈高,受日照持续时间长、强度大的路基西坡面路基土含盐量明显大于东坡面含盐量,氯离子质量分数远小于硫酸根离子质量分数,氯盐对硫酸钠盐渍土膨胀的抑制作用并不明显,可见阿拉善额济纳地区特殊的气候环境条件与工程地质条件使得路基土逐渐硫酸盐渍化并发生盐胀,是额济纳地区已建公路产生横向凸起病害的重要原因.     

基于生态账户的农田生态补偿空间转移研究——以武汉城市圈48个县(市、区)为例

论文以区域农田生态服务价值为基础,以经济发展程度、区域农田生态赤字/盈余与区域提供的生态承载力比值为调节系数,建立农田生态补偿空间转移模型,基于农田生态账户的概念从县(市、区)级层面对武汉城市圈48个县(市、区)的农田生态补偿空间转移额度进行测算。结果显示:1武汉城市圈农田生态系统服务总价值为75.00×108元,涉及农田生态补偿空间转移额2.31×108元。2 48个县(市、区)中,24个为农田生态支付区,支付区中武昌区的支付量最大,达到5 967.92×104元,最小为14.94×104元(铁山区);24个受偿区中最大受偿额为238.91×104元(黄陂区),最小为5.14×104元(英山县)。3农田生态补偿空间转移量占地方当年财政收入的比例在0.07%~5.24%之间波动。论文提出的农田生态补偿空间转移模型简单、可行,也适用于其他更高或更低的尺度上有农田分布的地区进行农田生态补偿空间转移额度的核算。     

近20a三峡库区农林地利用变化图谱特征分析

土地利用变化图谱单元能够把表示"空间单元特征的图"与表示"时间发展之起点与过程的谱"合为一体,并建立起空间—属性—过程一体化数据信息。论文以TM/ETM影像为空间数据源,构建三峡库区1990—2000年和2000—2010年两个阶段农林地利用变化信息图谱,以及融合1990、2000、2010年这三个时期土地利用现状的变化模式图谱,以探讨库区近20 a来的农林用地变化轨迹和特征规律。结果表明:1 1990—2000年阶段的农林地利用变化图谱主要以农林地间及其和草地互换、建设用地占用农林地的图谱单元类型为主。空间差异上最为显著的是"耕地→建设用地(编码15)"、"草地→林地(编码32)"和"林地→草地(编码23)",空间分离度较低。2 2000—2010年阶段的农林地利用变化图谱单元分离度增大,农林地利用发生转换空间进一步扩张。最显著变化的是"耕地→林地(编码12)"和"耕地→建设用地(编码15)"图谱单元类型,其次是农林地转换为水域图谱类型(编码14和24)的面积增大。3库区农林地利用变化模式以前期变化型和后期变化型为主,反复变化型和持续变化型发生概率较小,库区农林地利用的转换具有明显的时间阶段性特征。     

凌河保护区综合管理的洪水模拟预报研究

近年来,水文部门根据降水预报,探索流域洪水模拟预报,对密切监视暴雨洪水、做好防汛调度决策起到良好作用。文章在统计分析小凌河多年暴雨洪水的基础上,采用不同雨级平均24 h时段比率,进行凌河保护区洪水模拟预报成果编制研究。构建"以流域为单元、以干流为主线、以水库和河道水文站为控制节点"的流域河库联合模拟预报调度成果图表,实现流域水系河库模拟预报调度。通过科学的实时洪水调度可以调蓄洪水,减轻洪水灾害。同时,也可为流域洪水资源化提供保障和科学依据,实现流域的综合管理。     

SoundPLAN在交通噪声对住宅小区影响评价中的应用

采用实测法对小区内的代表性点位进行噪声监测,并记录主要道路的车流量,将实测的车流量及道路相关参数输入到SoundPLAN预测软件中进行预测,计算预测值与实测值的差值。结果表明,偏差在2.8 dB(A)以内说明该软件可以用于交通噪声对住宅小区的噪声影响预测。用SoundPLAN预测软件绘制了住宅小区的平面和横截面声等值线图,形象的表达了交通噪声对住宅小区的影响。     

三峡库区生态经济复合产业带的构建研究

由于自然尤其是人为因素的影响 ,三峡库区生态环境遭受严重破坏 ,农民增收缺少支撑 ,加上三峡工程的修建 ,淹没了大批肥田沃土 ,更加激化了人地矛盾 ,导致该地区生态环境恶化、生态承载容量减少、经济贫困化恶性循环 ,最终致使生态环境保护和经济发展严重对立。要从根本上解决库区生态环境与经济的协调发展问题 ,关键在于发展生态经济。从三峡库区以山地、丘陵为主的地形特征及其分布特点和气候、土壤条件以及资源特色出发 ,根据生态学、生态经济学的基本原理要求 ,提出了建立由水域生态经济产业带、沿江经济支撑产业带、腹地生态农业带、高山垂直绿色产业带构成的生态经济复合产业带的构想 ,其中每个产业带又由若干关联性强的产业有机复合而成。还提出了发展三峡库区生态经济的具体政策建议和措施。     

Conservation in Brazil's Chocolate Forest: The Unlikely Persistence of the Traditional Cocoa Agroecosystem

/ In southern Bahia, Brazil, the traditional cocoa agroecosystem with a dense shade canopy of native trees is now recognized as a secondary conservation route for highly endangered Atlantic Rainforest species. This "chocolate forest" of the densely shaded farms persists despite a massive 20-year Brazilian government modernization program in which shade was seen as a chief impediment to raising cocoa production. The objective of this study was to determine how this traditional agroecosystem endured. Although dense shade limits cocoa yield, it provides several agroecological benefits: control of insect pests and weeds, microclimate stability, and soil fertility maintenance. A keycomponent of modernization efforts was a shade-tree removal program designed to maximize cocoa production by using low shade and fertilizer while substituting agrochemicals for many beneficial roles of the overhead trees. This research found that many farmers rejected, or only partially accepted, the shade reduction process although it promised much higher cocoa yield and profit. Farmers employing a wide range of shading were interviewed, and it was found that decisions to remove or maintain the shade trees were linked to both agroecological and risk-minimization factors. Farmers' perceptions of the agroecological functions of the shade trees and individual willingness to entertain the economic risk associated with substituting agrochemicals for these were important. A less-profitable, but lower-risk approach of occasional fertilizer and agrochemical use with the traditional shade intact was a rational and widespread choice. Policies designed to maintain the traditional agroecosystem through the current economic crisis should heed the multiple functions of the overhead trees. KEY WORDS: Conservation; Brazil; Atlantic Rainforest; Cocoa; Agroecology; Risk; Agroforestry     

MODIFIED WATER QUANTITY RECEIVING MODEL FOR FLORIDA CONSERVATION AREAS1

ABSTRACT: The Conservation Areas in South Florida have been considered as one of the major water storage areas to provide a water supply for the Everglades National Park and Lower East Coast (LEC). Due to the increasing water demands of the area, additional backpumping of the surplus runoff from the LEC area into the Conservation Areas has been considered as one of several alternative plans. The Receiving Water Quantity (EPA, 1971) model has been adapted and modified to be applicable in the Conservation Areas to investigate the possible impact of additional inflow under various backpumping cases. The modification of the model included Manning's roughness coefficient, depth of flow, width of hypothetical channels through marsh areas, rainfall input, seepage rate, etc. The use of the Monte Carlo technique for area computations was found to be easy and time saving both in area and weighting rainfall input to each node. Comparison of results generated by this modified model with the recorded values in Conservation Areas 1 and 2A indicated that the model not only can be a very good evaluation tool to simulate the hydraulic regime of the Conservation Areas system but also a proper tool for investigating the impact of additional inflow resulting from the backpumping related to the water use planning and management.     

贫困地区旅游开发的土地利用--以安徽舒城县百丈岩旅游区为例

通过对贫困地区旅游开发过程中土地利用变化的分析,提出了土地利用变化的驱动力和评价原则,并根据旅游地生命周期理论,对未来土地利用的趋势和方向进行了分析,同时指出在开发旅游时应注意的问题.以安徽省舒城县百丈岩旅游区为例,在分析旅游开发可行性的基础上提出了本区的旅游发展战略,最后分析了旅游开发对土地利用结构变化的影响.