Evaluating the accessibility of urban parks and waterfronts through online map services: A case study of Shaoxing,China

Regular access to natural environment has many physical and mental health benefits for urban residents. This study was to evaluate the accessibility of urban parks and waterfronts in a Chinese canal city at the household level. Shaoxing, a typical canal town in the Yangtze River Delta region of China, was selected as the case study because of its abundant but underused natural resources. The study had measured the shortest travel routes from individual households to parks and waterfronts using data from the online map service and intensive fieldwork. The results showed that only 22% of Shaoxing residents live within a 500 m walking distance to parks, but scenario analysis showed if the canals were well used, almost all the residents would have access to natural environment within 15 min’ walk. Thus, the route-based accessibility evaluation method developed in this research offers a fine-grained understanding of household inequality in access to natural environments. It not only provides specific recommendations for planning intervention to improve the accessibility of natural resources in Shaoxing, but also contributes to the advancement of accessibility measures for planning practice. This route-based measure makes it possible to combine other accessibility measures of the travel routes such as sidewalk qualities in future research. The simplicity of this method means that it can be used to evaluate accessibility to other public facilities at the household level to develop walkable neighborhoods in cities.     

玉米秸秆覆盖还田保护性耕作技术在东北地区的应用与发展路径

玉米秸秆覆盖还田保护性耕作技术的应用可减少黑土流失、恢复与提升黑土肥力，是东北地区深入推进黑土地保护工作的必然选择。本文在概述其技术作业模式和适用范围的基础上，从经济效益、土壤“体质”和“体型”3个方面阐述技术实施效果，分析技术推广应用的现状以及在推广过程中存在的农户应用不积极、补贴制度不合理、农艺农机脱节等困境。未来应采取措施提高农户的响应程度，科学界定作业补贴的对象与金额，大力支持配套农机的研发与创新。     

基于改进多目标遗传算法的农村低碳物流配送路径优化

针对我国县、乡、村物流配送成本居高不下，需求覆盖率严重不足以及碳排放量较高的现实问题，构建考虑需求不确定和碳排放约束的农村物流配送路径优化模型，并提出了适用于多车型的改进多目标遗传算法。结合农村物流配送数据，运用MatlabR2014a软件进行仿真试验，最终得出在需求不确定和碳排放约束下农村物流的最优配送路径方案。仿真试验结果表明:设计的改进多目标遗传算法对于求解农村物流配送路径优化问题具有较好的有效性和适用性；在需求不确定和碳排放约束下，改进多目标遗传算法能够有效降低农村物流配送成本，提高需求覆盖率；与单车型配送方案相比，多车型配送方案在农村物流配送中更具优越性。     

环境规制如何嵌入农业政策:欧盟交叉遵守机制经验

构建农业发展与环境保护之间的协同机制是农业绿色发展过程中机制体制创新的重要方面。本文通过对欧盟交叉遵守机制的历史演进和运行机制的系统分析,探究其作用机理,明确政策运行特征,评估其积极影响和存在的问题。研究表明:①欧盟交叉遵守机制具有条件性、支付基础广泛、法规要求宽松、监督检查处罚机制严格、配套措施完善等特征;②机制对提升欧盟农业用地环境管理水平,改善环境政策执行效果,为欧盟农业支持提供合理化依据起到重要作用;③机制增加了行政成本和农民负担,且设定的仅是最低环境要求。基于以上研究结果,针对中国面临的如何协调农业发展与环境保护问题,本文提出树立农业发展方式转变的长久观、政策设计应侧重权责对等、构建可选择性交叉遵守试验区以及完善农业咨询服务等配套措施的政策建议。