常德市土壤水分平衡指标定量计算研究

土壤水分平衡指标是衡量某一区域土壤水分状况的重要标志，正确掌握某一区域的土壤水分平衡指标．有利于该区农业生产的合理布局和各种农作物的合理配置。定量计算表明：常德市的几种主要土壤水分平衡指标为：年可能蒸散量Ep919mm，年实际蒸散量E．906mm，土壤年缺水量D13mm，土壤年余水量R473mm。通过对常德市全年土壤水分收支情况的分析，得到了较为满意的结果，为有关方面提供了借鉴材料。     

Spatial variation in soil inorganic nitrogen across an arid urban ecosystem

We explored variations in inorganic soil nitrogen (N) concentrations across metropolitan Phoenix, Arizona, and the surrounding desert using a probability-based synoptic survey. Data were examined using spatial statistics on the entire region, as well as for the desert and urban sites separately. Concentrations of both NO₃-N and NH₄-N were markedly higher and more heterogeneous amongst urban compared to desert soils. Regional variation in soil NO₃-N concentration was best explained by latitude, land use history, population density, along with percent cover of impervious surfaces and lawn, whereas soil NH₄-N concentrations were related to only latitude and population density. Within the urban area, patterns in both soil NO₃-N and NH₄-N were best predicted by elevation, population density and type of irrigation in the surrounding neighborhood. Spatial autocorrelation of soil NO₃-N concentrations explained 49% of variation among desert sites but was absent between urban sites. We suggest that inorganic soil N concentrations are controlled by a number of ‘local’ or ‘neighborhood’ human-related drivers in the city, rather than factors related to an urban-rural gradient.     

氮肥施用对冬小麦土壤残留NO3^——N含量及根系分布影响

通过6个氮水平试验，研究了不同氮肥用量对冬小麦土壤剖面NO3^--N含量及其与根系空间分布对应关系的影响；探索了土壤剖面NO3^--N含量与氮肥施用量的趋势规律，以及冬小麦施用氮肥对地下水造成污染的成因、规律及最危险时期。     

悬浮液进样石墨炉原子吸收光谱法测定土壤样品中微量硒

采用悬浮液进样石墨炉原子吸收光谱法测定土壤样品中微量硒，选用钯－抗坏血酸为基体改进剂、锆涂覆石墨管。以标准物质制作校正曲线等一系列措施，有效消防共存元素的干扰，并保证了标准系列与土壤样品的原子化条件的一致性，获得了满意的分析结果。     

ATSDR Science Panel on the Bioavailability of Mercury in Soils: Lessons Learned

On the basis of discussion and analysis during and following an ATSDR science panel on the bioavailability of mercury in soils, it is apparent that the default assumption of 100% relative bioavailability for mercury-contaminated soils is excessively conservative. However, current knowledge does not allow the development of default assumptions or guidelines for determining relative bioavailability of mercury in soils. Until such default assumptions or guidelines can be developed, site-specific assays of bioavailability, preferably using either animal bioassays or validated in vitro techniques, may provide the best approach for estimating soil-mercury bioavailability.     

嘉庆六年京畿特大水灾生态原因及历史教训探析

嘉庆六年（1801）永定河决口，酿成五百年一遇的特大洪水。京畿直隶一带一百三十余个州县中，受灾地区达九十多个，堤防崩坍，房屋被毁，灾民流离失所，农作物减产绝收，给国家建设和人民生活带来重大损伤。此次灾害的原因既有17世纪全球整体气候变化所导致的极端天气，也有永定河特殊的地理情况，更有长期不当垦荒和滥砍滥伐所导致的严重的水土流失等原因。反思此次特大水灾的生态原因及历史教训，对于历史上整体大气候特别是极端气候的归纳分析，以及对今天的森林资源保护与正确开发等问题都具有重要的借鉴意义。     

诗化了的童年梦想和童年梦想的诗化——《社戏》、《故乡》中的童年

《社戏》、《故乡》中的儿童乡村生活是鲁迅诗化童年的梦想和童年梦想的诗化 ,鲁迅把自己对故乡的情感和他的立人思想灌注于他笔下的诗性故乡中 ,从诗性的故乡中汲取强大的精神力量以对抗生存的痛苦感、焦虑感     

设立中央政府投资基金 建立国土整治基地

中国西部地区尤其是大西北是我国三大经济带中经济发展相对落后的地域,由于历史和众多因素的制约,决定了开发西部是一项规模宏大、影响长远的系统工程,正基于此,各种开发方案的设计必须立足于这一区情.因此,设立中央政府投资基金,建立国土整治基地是非常必要,也是切实可行的.     

沙地衬膜水稻品种观察试验研究

通过对中国农业大学的中作58、9904、中作9363、天津水稻所的超优一号、辽宁稻作所的辽梗294和当地品种铁梗5号(CK)进行品种的农艺性状的观察和产量比较试验,选出了耐瘠薄、分蘖性强、抗逆性好、植株生长整齐、抽穗整齐、成穗率高、适合毛乌素沙地榆林沙区衬膜水稻栽培的主栽品种超优一号和搭配品种辽梗294、铁梗5号等一批优良品种。     

深厚表土层冻结孔井斜控制技术

结合工程施工实践,针对冻结孔施工中的井斜控制技术进行了初步应用研究,优化后的井斜控制技术成功地用于工程施工。