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1.
孔庆友 《中国人口.资源与环境》2005,15(2):132-135
山东省正处于工业化的中期阶段。矿产资源可持续利用面临重大挑战。本文分析了我国矿业大省——山东省的矿产资源开发利用存在的问题。提出山东省提高矿产资源的保障能力、促进矿产资源可持续利用的对策建议。 相似文献
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本文详细总结了华北地区下古生界海相烃源岩中芳烃生物标志物特征,主要包括菲系列、联苯系列、苯并芴系列,三芴系列、荧蒽系列、芘系列、苯并荧蒽和苯并芘系列、 系列和三芳甾烷系列,而萘系列含量较低。我们发现三芳甾烷C(28)(20S)/C(28)(20R)比值似乎显示了较好的热演化特征。 相似文献
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全球环境变化给发展中国家和南北关系带来深刻影响,理解环境问题的全球不平等需要以发展中国家80年代开始的经济结构调整和沉重债务为背景。南方的环境政策优先在很大程度上与其生活的可持续性相连,而不是通常与全球环境变化的长期性风险相关,然而,全球环境变化又与发展中国家贫困人口的日常生活紧密相关。从南方的立场看,当“问题”对他们不十分迫切时,就很难同意采取措施,仅此原因,北方对全球环境变化的关切要得到成功回应,真正的全球契约就需要解决基本“发展”问题,主要是贫困。 相似文献
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Paul V Bolstad Wayne T Swank 《Journal of the American Water Resources Association》1997,33(3):519-533
ABSTRACT: Water quality variables were sampled over 109 weeks along Coweeta Creek, a fifth-order stream located in the Appalachian mountains of western North Carolina. The purpose of this study was to observe any changes in water quality, over a range of flow conditions, with concomitant downstream changes in the mix of landuses. Variables sampled include pH, HCO32?, conductivity, NO3??-N, NH4+-N, PO43?-P, C1?-, Na, K, Ca2+, Mg2+, SO42?, 5iO2, turbidity, temperature, dissolved oxygen, total and fecal coliform, and focal streptococcus. Landcover/landuse was interpreted from 1:20,000 aerial photographs and entered in a GIS, along with information on total and paved road length, building location and density, catchment boundaries, hydrography, and slope. Linear regressions were performed to relate basin and near-stream landscape variables to water quality. Consistent, cumulative, downstream changes in water quality variables were observed along Coweeta Creek, concomitant with downstream, human-caused changes in landuse. Furthermore, larger downstream changes in water quality variables were observed during stormflow when compared to baseflow, suggesting cumulative impacts due to landscape alteration under study conditions were much greater during storm events. Although most water quality regulations, legislation, and sampling are promulgated for baseflow conditions, this work indicates they should also consider the cumulative impacts of physical, chemical, and biological water quality during stormflow. 相似文献
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Recent research has focused on establishing the values of preserving biodiversity both in agriculture and in less managed ecosystems, and in showing the importance of the role of cultural diversity in preserving biodiversity in food production systems. A study of the philosophy embedded in cultural systems can reveal the importance of the technological information for preserving genetic biodiversity contained in such systems and can be used to support arguments for the protection/preservation of cultural diversity. For example, corn or maize can serve as a paradigm of Native American thinking and can provide one of the few areas from which common philosophical conceptions can emerge. An examination of the cultivation of corn or maize as an agricultural activity and as a cultural activity in Native American literature reveals a philosophy that recognizes the importance of biodiversity and provides techniques for its preservation. Corn, and the food and the materials derived from it, is something thought out, not by specialists, but by the entire tribe and its ancestors, even if this thinking is done within what we might consider a framework of highly mythical notions. Importantly, this framework yields an understanding of both the genetics and nutrition of corn. A survey of these mythical notions (myths and stories) and agricultural practices makes this thought explicit and exemplifies the value of cultural diversity and biodiversity. 相似文献
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长期施肥对土壤有机质积累的影响 总被引:4,自引:0,他引:4
20年的NPK施肥定位试验,有利于深刻揭示土壤肥力特征与营养平衡规律。以位于黄淮海平原的中国科学院禹城综合试验站为例,探讨和估算了长期定量施肥对冬小麦(TriticuspaestvumL.)、夏玉米(ZeaMaysL.)生长和土壤有机质(SOM)的影响。结果表明,长期的N、P肥配施或N、P、K均衡施肥,可显著增加SOM储量,并且后者要优于前者;SOM增加主要集中在0-20cm深度的土层,40-60cm基本不变;生物量对SOM储量变化影响明显,NPK,NP处理作物生长良好,作物残体输人明显优于其他处理;0-40cm可以代表该区用以计算土壤固碳潜力,并且在N、P、K均衡施肥条件下,0-40cm土层中SOM储量长期以来持续增加,并未达到上限,每年的平均固碳速率(以C计)达182.8kg·hm-1,约是全球平均水平的1.5倍,全国平均水平的1.1倍。华北平原若按N、P、K均衡施肥,农田土壤每年固碳潜力将达到1.6-2.4Tg·a-1。 相似文献