沂沭推覆拼贴带与山东地区金伯利岩

本文就沂沭推覆拼贴带构造地质特徽结合山东地区金伯利岩的时空关系探讨进一步寻找含金刚石金伯利岩的可能性。     

开发区协调发展规划研究——以本溪经济技术开发区为例

本文对如何制定开发区的协调发展规划,提出了以可持续发展思想为指导,以环境承载力为社会经济和环境协调发展的判据的研究思路,并以本溪经济技术开发区生态建设和环境综合规划为例进行了案例分析,验证了这一思路的可行性和合理性。     

Pyrophytic Properties of the Larch Larix gmelinii in Terms of Life Strategies

The pyrophytic properties of the larch Larix gmelinii (Rupr.) Rupr. growing in the northern taiga of central Siberia have been studied. It has been found that, although the trees are highly combustible and fire resistance of tree stands is low, the species is highly pyrophytic, which allows it to retain its geographic range. At early stages of postfire successions, the larch exhibits characteristics of pyrogenic explerent and is subject to r-selection. When forest restoration is close to completion, the species passes into the patient state and acquires properties subject to K-selection.     

土壤组分对磷形态和磷吸附-解吸的影响——基于三峡库区消落带落干期土壤

通过选择性去除土壤组分的方法,探讨了三峡库区消落带落干期3种典型土壤中有机质、铁氧化物组分对磷形态和磷吸附-解吸的影响.结果发现,三峡库区消落带落干期3种典型土壤去除的有机质以易氧化组分为主,去除有机质后,土壤中各种磷形态的含量变化较小.然而,去除游离铁氧化物后,土壤中各种磷形态的含量均发生明显降低.同时,去除有机质、游离铁氧化物组分后并未改变土壤中各种磷形态的相对大小顺序,均为：钙结合磷（Ca-P） > 有机磷（OP） > 铁/铝结合磷（Fe/Al-P）.此外,黄壤（FJ）、紫色潮土（KX）和灰棕紫泥（FL）去除有机质后对磷的吸附能力较原始土壤仅分别降低0.5%、2.3%、6.5%（P=0.017<0.05,显著性差异）,表明3种土壤中有机质组分对磷吸附的影响较小;而去除游离铁氧化物后对磷的吸附能力分别降低45.6%、51.7%、43.9%（P=0.004<0.05,显著性差异）,表明土壤中游离铁氧化物组分是决定磷吸附大小的重要因素.另外,3种土壤去除游离铁氧化物后较原始土壤吸附磷的解吸能力明显增加,表明游离铁氧化物组分是控制3种土壤吸附磷的解吸的重要因素.FL土壤去除有机质组分后较原始土壤吸附磷的解吸能力略有降低,而KX和FJ土壤去除有机质组分后较原始土壤吸附磷的解吸能力无明显差异,表明有机质组分对土壤吸附磷的解吸的影响与土壤类型有关.     

京津冀生态屏障区景观格局变化及其对水源涵养的影响

选择京津冀重要水源涵养区--滦河,潮河和白河流域,通过分析2010与2015年土地利用的变化及景观格局演变,研究该研究区的土地利用转移与景观格局特征的时空分布与变化特点;运用SWAT水文模型模拟分析该时段内研究区的水源涵养量分布与变化;并和降水分布特征进行对比分析.利用偏相关分析法,重点分析了景观格局的变化对水源涵养量的影响.结果表明水源涵养量与PLAND指数相关性为-0.846;与NP指数相关性为-0.635;与LPI指数相关性为0.468;与LSI指数相关性为0.523;与COHESION指数显著相关,相关性为0.918.景观格局和水源涵养量存在以下关系：①景观多样性越高,聚集程度越高,景观形状越复杂,越趋向不规则且优势度越高,越有利于水源涵养;②景观的破碎化程度越高,水源涵养量越低.     

基于RZWQM模型模拟太行山低山丘陵区农田土壤硝态氮迁移及淋溶规律

太行山低山丘陵区是华北平原地下水补给区,近年来山区农田面积增加,农田过量氮肥投入造成地下水硝酸盐浓度逐年升高,因此,研究典型农田土壤氮淋溶过程对保护补给区地下水具有重要意义.本文以位于太行山低山丘陵区的中国科学院太行山生态试验站冬小麦-夏玉米轮作农田为研究对象,应用根区水质模型（root zone water quality model,RZWQM）对太行山低山丘陵区2015~2016年冬小麦-夏玉米的1个轮作周期内1m土壤剖面水分和硝态氮运移进行模拟.结果表明,土壤硝态氮淋溶主要发生在夏玉米季（雨季）,当全年施氮量为300 kg·hm^-2时,夏玉米季硝态氮淋失量达到59.9 kg·hm^-2,而冬小麦生长季硝态氮淋失量仅为2.12 kg·hm^-2.不同施氮量和不同降水年型下玉米季土壤硝态氮淋溶模拟结果表明,当施氮量为0、300和450 kg·hm^-2时,2016年（丰水年）极端降水后,玉米季土壤硝态氮潜在淋失量分别为10.5、59.9和136.5 kg·hm^-2;当全年施氮量为300 kg·hm^-2时,2013（枯水年）、2015（平水年）和2016年（丰水年）玉米季硝态氮淋失量分别占轮作周期总施氮量的9%、10%和20%;当全年施氮量为450 kg·hm^-2时,2013（枯水年）、2015（平水年）和2016年（丰水年）玉米季硝态氮淋失量分别占总施氮量的11%、17%和30%,表明大降水事件不仅对地下水形成大量补给,很大程度上也增加了累积在农田土壤中的硝态氮淋溶损失,增加了对区域地下水硝酸盐潜在污染威胁.     

Restoration processes of pollution zones in Hanjiang River

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Removal of NAPLs from the unsaturated zone using steam: prevention of downward migration by injecting mixtures of steam and air

Steam injection for remediation of porous media contaminated by nonaqueous phase liquids has been shown to be a potentially efficient technology. There is, however, concern that the technique may lead to downward migration of separate phase contaminant. In this work, a modification of the steam injection technology is presented, where a mixture of steam and air was injected. In two-dimensional experiments with unsaturated porous medium contaminated with nonaqueous phase liquids, it was demonstrated how injection of pure steam lead to severe downward migration. Similar experiments, where steam and air were injected simultaneously, resulted in practically no downward migration and still rapid cleanup was achieved. The processes responsible for the prevention of downward migration when injecting steam-air mixtures were analyzed using a nonisothermal multiphase flow and transport model. Hereby, three mechanisms were identified and it was demonstrated how the effectiveness of these mechanisms depended on the air-to-steam mixing ratio.     

Natural factors and human modifications contributing to marsh loss in Louisiana's Mississippi River Deltaic Plain

Natural factors and human modifications contribute to the estimated annual loss of 10,200 ha of coastal land in the Mississippi River Deltaic Plain Region of south Louisiana. This paper combines information on regional geology and human-induced habitat alterations to evaluate the relative importance of human and natural factors to marsh loss. Data on marsh area and habitat type for 139 7.5-min quadrangles were calculated from maps based on aerial photographs from 1955/56 and 1978, and data on regional geology obtained from published maps were used to construct multivariate model relating initial marsh area, change in urban and agricultural area, change in canal and spoil area, canal area in 1978, depth of sediment overlying the Prairie terrace, and subdelta age to marsh loss. The model indicated that between 25.0% and 39.0% of the marsh loss that occurred during the 23-year period was related to canal and spoil construction, and between 9.5% and 12.7% was related to urban and agricultural development. These are minimal estimates of loss because they do not include many secondary effects (for example, canal orientation, saltwater intrusion, and eutrophication) that can also result in indirect loss. Depth of sediment, initial marsh area, delta lobe age by 1978 canal and spoil area interaction, and indirect effects not included in the model accounted for remaining marsh loss.