Modelling nitrogen fluxes at the landscape scale

The distribution and impacts of different nitrogen pollutants are inextricably linked. To understand the problem fully, the interactions between the different pollutants need to be taken into account. This is particularly important when it comes to abatement techniques, since measures to reduce emissions of one nitrogen pollutant can often lead to an increase in another. This project represents a step towards greater understanding of these issues by linking together new and existing nitrogen flux models into a larger framework. The modelling framework has been constructed and some of the nitrogen flows between fields, farms and the atmosphere have been modelled for a UK study area for typical farm management scenarios.     

Rapid amino acid cycling in arctic and antarctic soils

Amino acids constitute one of the largest inputs of organic nitrogen (N) to most polar soils and have been hypothesized to be important in regulating vegetational succession and productivity in Arctic ecosystems. Our understanding of amino acid cycling in these soils, however, is poor. The aim of this study was to investigate the size and rate of turnover of the amino acid pool in a range of Arctic and Antarctic soils. Our results indicate that in polar soils with either high or low ornithogenic inputs the amino acid pool is small in comparison to the inorganic N pool (NO^–₃ and NH⁺₄). The free amino acid pool constituted only a small proportion of the total dissolved organic nitrogen (DON) pool in these soils. Here we show that these low concentrations may be due to rapid use by the soil microbial community in both Arctic and Antarctic soils. The turnover of the amino acid pool in soil was extremely rapid, with a half-life ranging from 2 to 24 h, indicating that this N pool can be turned over many hundred times each summer when polar soils are frequently unfrozen. The implications of amino acids in N cycling and plant and microbial nutrition are discussed.     

Applying metabolic fingerprinting to ecology: The use of Fourier-transform infrared spectroscopy for the rapid screening of plant responses to N deposition

The potential for metabolic fingerprinting via Fourier-transform infrared (FT-IR) spectroscopy to provide a novel approach for the detection of plant biochemical responses to N deposition is examined. An example of spectral analysis using shoot samples taken from an open top chamber (OTC) experiment simulating wet ammonium deposition is given. Sample preparation involved oven drying and homogenisation via mill grinding. Slurries of a consistent dilution were then prepared prior to FT-IR analysis. Spectra from control, 8 and 16 kg N ha^–1 yr^–1 treatments were then subjected to cross-validated discriminant function analysis. Ordination diagrams showed clear separation between the three N treatments examined. The potential for using Calluna vulgaris (L.) Hull as a bioindicator of N deposition is further evident from these results. The results also clearly demonstrate the power of FT-IR in discriminating between subtle phenotypic alterations in overall plant biochemistry as affected by ammonium pollution.     

Impact of Land Use on Soluble Organic Nitrogen in Soil

Although it has been hypothesized that soluble organic nitrogen (SON) plays a central role in regulating productivity in some terrestrial ecosystems, the factors controlling the size of the SON pool in soil remain poorly understood. Therefore our principal aim in this work was to assess the impact of seven different land use systems (rough and managed grassland, deciduous and coniferous woodland, heathland, wetland and tilled land) on the size of the SON and inorganic N (NO ₃ ^– , NH ₄ ⁺ ) pools in the surface soil layer (0–15 cm). After extraction with deionised water, we found that in most cases the size of the water extractable organic N (WEON) pool was similar in size to the inorganic N pool. In contrast, the KCl extractable organic N (KClEON) pool constituted the dominant form of soluble N in soils under all land uses, perhaps indicating that significant amounts were held on the soil exchange phase. In contrast to inorganic N, which varied significantly with land use, the size of the KClEON and WEON pool was similar for all land uses with the exception of KClEON in tilled land, where significantly lower amounts were observed. We conclude that SON constitutes an important soil N pool in a broad range of land uses, and that its role in microbial N assimilation, plant nutrition and ecosystem responses to atmospheric N deposition warrants further attention. SAFRD, University of Newcastle, Newcastle-upon-Tyne, NE1 7RU, U.K.     

超声-双氧水和亚铁离子体系处理含酚废水研究

在实验装置上对超声-双氧水和亚铁离子体系联合处理含酚废水进行了实验研究。主要考察了废水初始pH值、初始双氧水浓度、超声功率、反应时间等因素对酚去除率的影响。实验结果表明：超声辐射可以在双氧水和亚铁离子体系氧化过程中起加速反应的作用，而且随着超声功率的增大，加速反应的能力增强；实验条件下废水初始pH值为4～6．8，初始双氧水浓度为140mg／L时酚去除效果最佳；超声-双氧水和亚铁离子体系处理含酚废水过程中苯酚的降解规律符合表现一级反应。     

环境可持续发展理论体系框架的构建

环境问题包括生态环境与社会、经济与生态环境关系两方面的问题，本文从社：会、经济、文化以及环境科技发展等不同角度论述了环境可持续发展理论体系框架的构建，认为环境可持续发展必须是在体现公平性、可持续性、协调性的基础上，建立以生态思维为基础的社会环境伦理观、发展环境科学技术、实现经济的有机增长，不断完善环境政策与环境法制体系，     

夹点技术--一种有效的清洁生产方法

夹点技术作为一种有效的清洁生产措施可用于能源优化、资源节约、废物减量及污染防治等方面，能收到良好的经济效益和环境效益。本文介绍夹点技术的基本原理、应用研究领域及其发展趋势。     

多级模糊综合评判方法在泥石流评价中的应用

介绍了多级模糊综合评判方法在泥石流评价中的应用, 指出了在进行模糊评判的时候,评判因子的选取以及隶属函数的构造应具体结合泥石流自身的特点来进行,并应用此方法对西南某拟建水电站坝址附近泥石流沟危险性做出了评价,评价结果与实际调查结果比较吻合.     

煤矿安全预评价的未确知测度模型及应用

矿井自然灾害的安全预评价涉及不确定因素众多.本文根据未确知数学理论,建立了预评价指标体系、置信度识别准则及评分准则,构造了矿井安全预评价未确知测度模型,并对矿井的各个安全指标进行了定量分析.用上述方法对黄陵二号井自然灾害的评定结果与实际耦合较好,从而为煤矿建设项目的安全预评价开辟了一条新途径.     

黄河积石峡水电站库区泥石流危险度评价

在选取一次(可能)最大冲出物方量、泥石流发生频率、流域面积、主沟长度、流域相对高差、流域切割密度、泥沙补给段长度比7个因子为泥石流沟谷危险度划分的主要因子的基础上,对评价因子隶属度的确定作了分析和阐述,并运用模糊综合评判法对黄河上游积石峡水电站库区16条泥石流沟进行了危险度划分.