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421.
简要论述了湖州市笋竹资源的特征和开发潜力,对笋竹资源开发现状予以评价,并对合理开发与保护,促进竹资源持续发展提出了对策。  相似文献   
422.
Burning fossil fuel in the North American continent contributes more to the CO2 global warming problem than in any other continent. The resulting climate changes are expected to alter food production. The overall changes in temperature, moisture, carbon dioxide, insect pests, plant pathogens, and weeds associated with global warming are projected to reduce food production in North America. However, in Africa, the projected slight rise in rainfall is encouraging, especially since Africa already suffers from severe shortages of rainfall. For all regions, a reduction in fossil fuel burning is vital. Adoption of sound ecological resource management, especially soil and water conservation and the prevention of deforestation, is important. Together, these steps will benefit agriculture, the environment, farmers, and society as a whole.  相似文献   
423.
Extensive losses of semi‐natural rural biotopes have led to pressures for conservation and habitat creation. Of particular concern is the loss of large‐scale structure and regional distinctiveness. If this is to be regained, planners will require both an effective body of theory relating to large‐scale visual and ecological cohesion, and effective methods of implementation. This study reviews the value of landscape ecology as a theoretical framework and discusses some applications, with particular reference to the re‐forestation of lowland Britain.  相似文献   
424.
Composting has emerged as a valuable route for the disposal of urban waste, with the prospect of applying composts on arable fields as organic amendments. Proper management of urban waste composts (UWC) requires a capacity to predict their impacts on carbon and nitrogen dynamics in the field, an issue in which simulation models are expected to play a prominent role.Here, we used a deterministic soil-crop model to simulate C–N dynamics in an arable field amended with three types of UWC (green waste and sludge, biodegradable waste, and solid waste), and a reference amendment (farmyard manure). The model is a version of CERES in which the soil C–N module was substituted with the NCSOIL model, whose microbiological parameters were determined from either laboratory incubation data or biochemical fractionation in a previous paper. CERES was tested against data from a field trial set up in 1998 in the Paris area, and managed as a maize (Zea mays L.)–wheat (Triticum aestivum L.) rotation. Comparison of observed and simulated data over the first 4 years of the field trial showed that CERES predicted the soil moisture and inorganic N dynamics reasonably well, as well as the variations in soil organic C. In particular, the parameterization of UWC organic matter from biochemical fractions achieved a similar fit as the parameterization based on incubation data. Wheat yields were also correctly predicted, but a systematic under-estimation of maize yields pointed at an under-estimation of spring and summer mineralization of N by CERES.Simulated N fluxes showed that the organic amendments induced an additional leaching ranging from 1 to 8 kg N ha−1 yr−1, which can be related to the initial mineral N content of the amendments. After 4 years, the composts had mineralized 3–8% of their initial organic N content, depending on their stability. Composts with slower N release had higher N availability for the crops. CERES could thus be used to aid in selecting the timing of compost application, in relation to its stability, based on both environmental and agronomical criteria.  相似文献   
425.
协同论、城市生态学及苏州河综合整治   总被引:1,自引:0,他引:1  
从协同论和城市生态学的角度,对苏州河综合整治的定义、目的、方式进行了阐述了探讨。  相似文献   
426.
西藏阿里地区的林业资源及其发展方向探讨   总被引:1,自引:1,他引:1  
该文对西藏阿里地区林业资源的类型、数量、质量特征和生产现状进行了深入分析,同时,探讨了该地区林业生产存在的“资源结构简单、后续资源极端贫乏;资源分布不均,水平和垂直分异突出;宜林荒山荒地资源面积大,造林任务艰巨、生态环境破坏严重”等主要问题,提出了如下的对策和建议:①健全林业行政管理体制,加强林业资源管理;②节省薪柴,保护生态环境;③实行林地承包制,大力兴办林业;④加强林业科技投入,以科技兴林,走林业可持续发展之路。  相似文献   
427.
城市生活垃圾综合处理研究   总被引:13,自引:0,他引:13  
简述城市生活垃圾单一处理方法中存在的不足与局限 ,指出综合处理作为一种先进的处理技术 ,是实现垃圾资源化处理的关键 ,并达到垃圾处理的减量化、无害化目的 ,而分选技术是垃圾综合处理的关键技术。就如何实现垃圾的综合处理提出了相应对策。  相似文献   
428.
介绍了沈阳可持续发展项目并探讨了该项目对沈阳市实施可持续发展的影响,突出了实施可持续发展战略对沈阳的影响,并对如何实施沈阳可持续发展战略、做好沈阳可持续发展项目提出了建议.  相似文献   
429.
我国城市污水几种处理工艺简介   总被引:5,自引:0,他引:5  
介绍了近年来城市污水处理工程中常见的几种处理工艺和主要设计参数。  相似文献   
430.
Traditional air quality data have a spatial resolution of 1 km or above, making it challenging to resolve detailed air pollution exposure in complex urban areas. Combining urban morphology, dynamic traffic emission, regional and local meteorology, physicochemical transformations in air quality models using big data fusion technology, an ultra-fine resolution modeling system was developed to provide air quality data down to street level. Based on one-year ultra-fine resolution data, this study investigated the effects of pollution heterogeneity on the individual and population exposure to particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), and ozone (O3) in Hong Kong, one of the most densely populated and urbanized cities. Sharp fine-scale variabilities in air pollution were revealed within individual city blocks. Using traditional 1 km average to represent individual exposure resulted in a positively skewed deviation of up to 200% for high-end exposure individuals. Citizens were disproportionally affected by air pollution, with annual pollutant concentrations varied by factors of 2 to 5 among 452 District Council Constituency Areas (DCCAs) in Hong Kong, indicating great environmental inequities among the population. Unfavorable city planning resulted in a positive spatial coincidence between pollution and population, which increased public exposure to air pollutants by as large as 46% among districts in Hong Kong. Our results highlight the importance of ultra-fine pollutant data in quantifying the heterogeneity in pollution exposure in the dense urban area and the critical role of smart urban planning in reducing exposure inequities.  相似文献   
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