临江灌区工程环境影响评价中盐分平衡的分析与计算

灌区盐分平衡状态的分析与计算是灌区工程环境影响评价工作中的重要内容之一。通过以临江灌区工程为例,详细分析和计算了该灌区建成前后的盐分平衡状况,为灌区生态与环境保护提供了科学依据。盐分平衡动态过程的分析应建立在灌区水量平衡的基础上,应获取灌区土壤、地表水、地下水、灌区水源水以及灌区排水中的盐分浓度,同时还应获取灌区建成前后化肥使用量变化、地表生物量的累积变化以及生物质中的盐分含量等相关参数。文中所提供的灌区盐分平衡分析与计算方法对丰富农林水利类工程的环境影响评价理论具有参考意义。     

秦皇岛市森林生态系统现状分析

通过分析秦皇岛市当前森林生态系统的现状、效益,发现秦皇岛市森林生态系统存在着分布不均、林龄结构不合理等问题;提出了退耕还林、封山育林、加大宣传力度等措施,以期秦皇岛森林生态系统走上可持续发展的道路,更好地造福于人民。     

乌昌地区城镇污水处理方式探讨

随着乌昌经济的发展,城市人口快速增长,生活污水的排放量剧增,对环境造成直接和潜在威胁。通过对乌昌地区城镇污水处理现状,昌吉州人工防护林建设状况分析,结合防护林用水量及地下水资源现状分析。探讨城镇污水处理的全新模式,从其生态效益、环境效益、社会效益和经济效益做了分析阐述。     

京津冀地区“煤改电”对PM2.5污染的健康效益评估

为准确评估京津冀地区采暖期实施“煤改电”政策带来的健康效益,估算了京津冀地区各区县采暖期“煤改电”政策实施前后PM_2.5污染导致的过早死亡人数,并采用支付意愿法计算了相应的健康损失价值.结果表明,京津冀地区“煤改电”政策实施后带来了1 745人(95%CI:1 443～1 907)健康效益和23.78亿元(95%CI:14.50～30.63)经济效益.北京、天津及河北地区的健康效益分别为495人(95%CI:436～554)、 296人(95%CI:238～354)及954人(95%CI:693～1 076).经济效益分别为3.50亿元(95%CI:3.08～3.92)、 3.32亿元(95%CI:2.67～3.96)及16.96亿元(95%CI:8.75～22.75),分别占各地区GDP的0.01%、 0.02%及0.04%. COPD、 LC、 ALRI、 IHD、 STROKE减少的死亡人数分别为187人(95%CI:165～224)、 318人(95%CI:178～458)、 193人(95%CI:115～204)、 506人(95%CI:232～780)...     

不同再生水灌溉方式对土壤-辣椒系统中细菌群落多样性及病原菌丰度的影响

再生水是改善水资源布局和缓解传统水源短缺问题的一种合理且可持续的替代水源,但用于灌溉会引起土壤和作物中微生物群落结构和条件致病菌丰度变化,目前这方面的研究报道较少.本研究以辣椒为对象,设置再生水灌溉(DI)、清水和再生水混灌(MI,清水∶再生水=1∶1)、清水和再生水轮灌(RI)处理,以清水灌溉(PI)为对照,通过温室盆栽试验研究不同灌溉方式对土壤性质的影响,并基于高通量测序技术结合定量PCR方法探讨再生水灌溉下辣椒果实与根际细菌群落组成和病原菌分布丰度特征.结果表明,与清水灌溉相比,再生水直接灌溉增加了土壤EC值,而降低了pH值.16S r DNA高通量测序结果显示,在门分类水平上,Proteobacteria、Bacteroidetes、Actinobacteria和Firmicutes是辣椒果实和根际共有的主要类群,其优势菌属Pantoea、Pseudomonas、Sphingomonas、Sphingopyxis、Luteimonas和Mariniflexile的相对丰度受再生水灌溉方式的影响较大.再生水灌溉分别使辣椒果实和根际中Legionella spp.和Pseudomonas syringae丰度显著增加,并且对病原菌丰度的影响差异较大.综上所述,再生水适宜作为农业灌溉用水,但不同灌溉方式可能不同程度上引入微生物污染问题,其中特定条件致病菌和植物病原菌值得关注.     

茂名小良桉树人工林生态经济效益分析与评价

利用模糊数学的方法,通过对小良的实地调杳和专家走访,挑选了30个对小良桉林生态经济影响较大的因子.建立了评价因子指标体系和五个评价等级,采用二个层次的综合评价模型对小良桉林生态经济效益首次进行了定量的综合评价.评价结果是:现在小良桉林生态经济效益为一般.总体态势是:16%为好,26%为较好,31%为一般.23%为较差,4%为差.综合评价得分为79.85分,介于一般和良好之间,这说明在小良桉树人工林的发展过程中存在许多显性的、潜在的问题,如果还不注意合理利用林地资源,就会使森林资源变为不可更新资源,不可持续利用.因此,科学客观地分析与评价小良桉林产业生态经济效益,为区域可持续发展提供科学依据和发展良策,实现生态和经济的综合调控具有现实意义.     

AN EVALUATION OF THE 1997 EDWARDS AQUIFER IRRIGATION SUSPENSION1

ABSTRACT: In early 1997, the Texas Edwards Aquifer Authority implemented a pilot Irrigation Suspension Program with the objectives of increasing springflow and providing relief to municipalities during drought. Irrigators were paid an average of $234 per acre to suspend water use, a price higher than regional land rental rates. Auction theory and program implementation details suggest that the program implementation partially caused inflated bids. The Irrigation Suspension Program is also compared to two alternative programs: (1) subsidizing more efficient irrigation technology and (2) buying land. The irrigation suspension is found to be more cost‐effective relative to subsidizing improved irrigation efficiency because it can be put in place only when aquifer levels are low. Land purchase is a cheaper alternative if the bid levels remain at the levels observed.     

唐山市农业区地下水垂向剖面中硝态氮污染的研究

当今农业地区灌溉施肥引起氮素对地下水的污染已成为人们普遍关注的环境问题.本文结合唐山市农业区的生产实际,应用LEACHN数学模型,对唐山市农业地区灌溉施肥条件下氮素在土壤中的迁移转化进行了模拟计算.所建立的地下水垂向剖面的二维水量水质模型,对典型剖面中地下水的硝态氮污染进行了模拟和分析.计算结果表明,唐山农业区灌溉施肥引起根区以下硝态氮渗漏损失可造成浅层地下水的污染.     

浅议林业安全生产与经济效益

浅析新形势下,林业安全生产存在的问题及其对经济效益的影响和对策。     

The Economic Consequences of Alien Plant Invasions: Examples of Impacts and Approaches to Sustainable Management in South Africa

The invasion of natural ecosystems by alien plants is a serious environmental problem that threatens the sustainable use of benefits derived from such ecosytems. Most past studies in this field have focussed on the history, ecology and management of invasive alien species, and little work has been done on the economic aspects and consequences of invasions. This paper reviews what is known of the economic consequences of alien plant invasions in South Africa. These economic arguments have been used to successfully launch the largest environmental management programme in Africa.Ten million hectares of South Africa has been invaded by 180 alien species, but their impacts are not fully understood, although they are undoubtedly significant. The indications are that the total costs of these impacts are substantial. Selected studies show that invasions have reduced the value of fynbos ecosystems by over US$ 11.75 billion; that the total cost of invasion would be about US$ 3.2 billion on the Agulhas Plain alone; that the net present cost of invasion by black wattles amounts to US$ 1.4 billion; that invasions by red water fern have cost US$ 58 million; and that the cost to clear the alien plant invasions in South Africa is around US$ 1.2 billion. These few examples indicate that the economic consequences of invasions are huge.One of the unique aspects of invasive plant control programmes in South Africa has been the ability to leverage further benefits (mainly through employment) for the expensive control programmes from the government's poverty relief budget. This has made it possible to allocate substantial funding to a programme that would otherwise have struggled to obtain significant support. Biological control of invasive species also offers considerable benefits, but is often the subject of debate. We believe that, at least in the case of many invasive alien plant species in South Africa, biological control offers one of the best, and most cost-effective, interventions for addressing the problem.