我国农村能源发展方针调整问题探讨

我国农村能源发展方针是“因地制宜,多能互补,综合利用,讲求效益”,这是在短缺经济的背景下,针对能源危机而提出来的。目前我国农村的社会、经济及其能源供需结构形势发生了重大变化,大量商品能进入农村市场,农村能源面临着结构升级和如何现代化的问题,原十六字方针因缺少生态观和市场观,已不符合现时和未来农村能源可持续发展的实际。文章提出了农村能源发展的十八字方针“因地制宜,生态兴能,市场调节,讲求综合效益”,并逐一对新方针中的论点进行了阐述,提出了我国应以生物质二次能源与商品能源整合的可持续能源的发展理念,提出了实施新方针的有关举措。     

Fluxes of NO3-, NH4+, NO,NO2, and N2O in an Old Danish Beech Forest

The fluxes of the major nitrogen compounds havebeen investigated in many ecosystem studies over the world.However, only in few studies has attention been drawn to theimportance of the fluxes of minor gaseous nitrogen compoundsto complete the nitrogen cycle. In Denmark a detailed study onthe nitrogen cycle in an old beech forest has been implementedin 1997 at Gyrstinge near Sorø, Zealand. The study includesthe fluxes of the gases NO, N₂O and water mediatedtransport of NO₃ ^- and NH₄ ⁺. Measurementsof the fluxes of the gaseous compounds are performed withmicro-meteorological methods (eddy-correlation and gradient)and with chambers. Water mediated fluxes encompass rain,throughfall, stem-flow and leaching from the root zone. Thehydrological model is verified by TDR measurements. The findings show that the total water mediated N input tothe forest floor with throughfall and stemflow was 25.6 kg Nha^-1 yr ^-1, and open field wet deposition withprecipitation was 19.0 kg N ha^-1 yr ^-1. The internalcycling of N in the ecosystem measured as turnover oflitterfall and plant uptake was 100 kg N ha^-1 yr ^-1and 14 kg N ha^-1 yr ^-1, respectively. The fluxes ofthe gaseous N compounds NO and N₂O were of minorimportance for the total N turnover in the forest, NO_xemission being <1 kg N ha^-1 yr ^-1 and N₂Oemission from the soil being 0.5 kg N ha^-1 yr ^-1 withno significant difference between wet and dry soils.Concentrations of NO₃ ^- and NH₄ ⁺ in thesoil solution beneath the rooting zone are very small andconsequently the N leaching is almost negligible. It isconcluded that the nitrogen mass balance of this old beechforest ecosystem mainly is controlled by the input by dry andwet deposition and a large internal N cycle with a fast litterturnover. The nitrogen input tothe forest ecosystem which currently exceeds the critical loadby 5 kg N ha^-1 yr ^-1is mainly accumulated in the soil and no significant nitrateleaching is occurring.     

环境与生态系统资本价值评估的若干问题

近年来,环境与生态系统资本价值评估中的概念界定、系统价值认定及评价模式选择等之类的问题成为相关研究中有争议的议题.鉴于此,对环境与生态系统资本价值评估中的一些问题进行了探讨.①在肯定环境与生态系统资本价值评估意义的基础上,指出对于环境与生态系统的整体价值要予以充分估价;②针对目前评价模式单一的现状,提出了整合类型与区域评估的新模式;③在分析了环境与生态系统的资本价值在空间上流动之后,认为应对价值的积累和流动过程给予充分关注;最后,提出了几条具体的建议.     

UNCALCULATED IMPACTS OF UNSUSTAINABLE AQUIFER YIELD INCLUDING EVIDENCE OF SUBSURFACE INTERBASIN FLOW1

ABSTRACT: Unsustainable withdrawals from regional aquifers have resulted in adverse impacts considerable distances from the point locations of supply wells. In one area of the southeastern (SE) Coastal Plain, conservative estimates for repair/replacement of some residential wells damaged or destroyed by unsustainable yield from the Floridan aquifer system exceeded $4 million. However, a comprehensive assessment of damage/economic loss to private property and public resources due to unsustainable yield from that regional karst aquifer has not been made. Uncalculated direct costs to home‐owners from damage attributed to those withdrawals are associated with destruction of homes from increased sinkhole formation, devalued waterfront property, and removal of diseased and dead trees. Examples of other uncalculated economic burdens resulting from unsustainable aquifer yield in the SE Coastal Plain include: (1) irreversible damage to the aquifer matrix and concomitant increased potential for groundwater contamination, (2) large‐scale wildfires with subsequent degradation of air quality, debilitation of transportation corridors, and destruction of timber, wildlife habitat and property, and (3) destruction of “protected” natural areas. This paper provides a general background of the regional Floridan aquifer system's karst characteristics, examples of known impacts resulting from ground water mining in the SE Coastal Plain, and examples of additional damage that may be related to unsustainable yield from the Upper Floridan aquifer. Costs of these impacts have not been calculated and are not reflected in the price users pay for ground water. Evidence suggests that the classic watershed management approach must be revised in areas with mined regional karst aquifers to include impacts of induced recharge from the surficial aquifer, and subsurface inter‐basin flow. Likewise, associated impacts to surface water and interrelated systems must be calculated. The true cost of groundwater mining to this and future generations should be determined using a multidisciplinary approach.     

高寒草地土壤保持功能的风洞模拟及其定量评估

青藏高原高寒草地的土壤保持功能对于保护生态环境具有重要的作用。为了研究人类活动不同干扰方式对高寒草地土壤保持功能的影响,利用大型风洞,对不同干扰方式下高寒草甸、草原化草甸和高寒草原3个类型的土壤保持功能定量评估,以侵蚀率作为土壤保持功能的测度指标。实验结果表明,随着风速的增大,3个样品的土壤侵蚀率均呈现增大趋势,但不同处理下侵蚀率的增幅不同。当植被根系破坏后,土壤侵蚀率大小为高寒草甸<草原化草甸<高寒草原,说明,高寒草甸土壤的可蚀性低,高寒草原土壤的可蚀性高,极易遭到破坏。从总体来看,土壤保持功能的强弱依次为高寒草甸>草原化草甸>高寒草原。风蚀前后土壤中有机质和养分含量的变化分析表明,土壤有机质和养分含量显著下降,其中速效K2O的养分含量下降幅度最大。对3个草地类型单位面积土壤保持经济价值进行计算,计算主要包括保持有机碳、保持养分和减少土壤流失对河流湖泊淤积3个方面的价值。结果表明,高寒草原化草甸单位面积的土壤保持价值最高,其次为高寒草甸,高寒草原单位面积土壤保持价值最低。     

我国生态工业系统稳定性的结构型因素实证研究

在查阅国内外大量文献的基础上,提出了5个可能影响我国生态工业系统稳定性的结构型因素假设:关键种企业、成员距离、成员相互依赖程度、成员多样性、领导因素.并在全国47个生态工业系统进行统计实证研究加以证实.数据相关分析和回归分析结果表明:强有力的系统内部关键种企业、较少的成员交流障碍、较近的成员空间距离、多样化的成员企业主营业务等4个因素对我国生态工业系统稳定性有显著影响.对我国生态工业系统的发展提出了相应的政府决策建议.      

多卡金矿生态环境治理规划研究

针对多卡金矿开采中的生态环境问题,在对多卡金矿及自然环境、生态环境现状调查基础上,研究制定了多卡金矿生态环境治理规划,以实现生态系统健康,生态格局安全。     

Prognosis of the spatiotemporal dynamics of ecosystems by means of universal kriging

The use of quantitative data for constructing prognostic maps of the dynamics of ecosystem degradation and restoration by nonlinear simulation methods is a topical field of landscape ecology. This method of dynamic cartography is based on fiberwise comparison of data on the state of Chernye Zemli (the Kalmyk Republic, Russia) in different years and the detailed analysis of the period on which the prognosis was based. For this purpose, materials of repeated aerial and satellite photography obtained during a long period (1954–1993) were used. Comparison of maps characterizing the dynamics of Chernye Zemli between 1958 and 1993 allows prognostic electronic maps for the next 10–15 years (with a five-year interval) to be drawn and land prognosis for the next 20–30 years (1998–2023) to be obtained. Deceased     

La在模拟水生态系统中的动力学行为

采用140La放射示踪技术,研究了稀土元素镧（La）在模拟水生态系统各组分中的迁移分布规律．并建立了相应的数学模型．结果表明,La在模拟水生态系统各组分中的积累率大小依次为：金鱼藻＞底泥＞螺蛳＞鱼,La在系统内的动态变化规律可用封闭分室模型来描述．     

可持续发展的生态学思考

本文从生态学角度对可持续发展理论进行了思考。指出生态危机是可持续发展产生的基本背景;生态学中许多基本理论,如协调、适应、稳定、有序、循环再生及生态系统理论等,是可持续发展不断完善的理论基础;包括生态规划、生态技术与生态管理在内的广义生态工程,是实现可持续发展的有效途径