Effects of organic matter on Leymus chinensis germination,growth, and urease activity and available nitrogen in coastal saline soil

ABSTRACT

The present study was carried out to investigate the effect of three organic matters (stalk powder, microbial fertilizer, and manure) on Leymus chinensis germination, growth, and urease activity and available nitrogen (N) in coastal saline soil. The study was conducted in a completely randomized design with eight treatments: J₀V₀Y₀, J₁V₀Y₀, J₀V₁Y₀, J₀V₀Y₁, J₁V₁Y₀, J₁V₀Y₁, J₀V₁Y₁, J₁V₁Y₁. The notations were based on the quantities of each agent added to 1 kg of coastal saline soil: J₀ – no straw powder, J₁ – 0.2 kg straw powder, Y₀ – no manure, Y₁ – 0.3 kg manure, V₀ – no microbial fertilizer, V₁ – 0.2 L microbial fertilizer, each in quantic repeat. L. chinensis was sown as 50 seeds per pot. Results indicated that addition of organic agents exerted a significantly enhanced germination, increase in fresh weight and elevated soil urease activity. Soil available N levels were significantly positively correlated with soil urease activity and fresh weight, but not with germination rate. It is noteworthy that the halophyte L. chinensis showed improved characteristics when grown in coastal saline soil with addition of organic amendments.     

The Value of Using Feasibility Models in Systematic Conservation Planning to Predict Landholder Management Uptake

Understanding the social dimensions of conservation opportunity is crucial for conservation planning in multiple‐use landscapes. However, factors that influence the feasibility of implementing conservation actions, such as the history of landscape management, and landholders’ willingness to engage are often difficult or time consuming to quantify and rarely incorporated into planning. We examined how conservation agencies could reduce costs of acquiring such data by developing predictive models of management feasibility parameterized with social and biophysical factors likely to influence landholders’ decisions to engage in management. To test the utility of our best‐supported model, we developed 4 alternative investment scenarios based on different input data for conservation planning: social data only; biological data only; potential conservation opportunity derived from modeled feasibility that incurs no social data collection costs; and existing conservation opportunity derived from feasibility data that incurred collection costs. Using spatially explicit information on biodiversity values, feasibility, and management costs, we prioritized locations in southwest Australia to control an invasive predator that is detrimental to both agriculture and natural ecosystems: the red fox (Vulpes vulpes). When social data collection costs were moderate to high, the most cost‐effective investment scenario resulted from a predictive model of feasibility. Combining empirical feasibility data with biological data was more cost‐effective for prioritizing management when social data collection costs were low (<4% of the total budget). Calls for more data to inform conservation planning should take into account the costs and benefits of collecting and using social data to ensure that limited funding for conservation is spent in the most cost‐efficient and effective manner.     

Combined Effects of Levels of Protection and Environmental Variables at Different Spatial Resolutions on Fish Assemblages in a Marine Protected Area

Abstract: The links between species–environment relations and species’ responses to protection are unclear, but the objectives of marine protected areas (MPAs) are most likely to be achieved when those relations are known and inform MPA design. The components of a species’ habitat vary with the spatial resolution of the area considered. We characterized areas at two resolutions: 250 m² (transect) and approximately 30,000 m² (seascape). We considered three categories of environmental variables: substrate type, bottom complexity, and depth. We sought to determine at which resolution habitat characteristics were a better predictor of abundance and species composition of fishes and whether the relations with environmental variables at either resolution affected species’ responses to protection. Habitat features accounted for a larger proportion of spatial variation in species composition and abundances than differences in protection status. This spatial variation was explained best by habitat characteristics at the seascape level than at the transect level. Species’ responses to protected areas were specific to particular seascape characteristics, primarily depth, and bottom complexity. Our method may be useful for prioritizing marine areas for protection, designing MPAs, and monitoring their effectiveness. It identified areas that provided natural shelter, areas acting as buffer zones, and areas where fish species were most responsive to protection. The identification of such areas is necessary for cost‐effective establishment and monitoring of MPAs.     

铁炭内电解垂直流人工湿地对污水厂尾水深度脱氮效果

针对污水厂尾水总氮(TN)含量偏高、微生物可利用碳源低的问题,构建铁炭内电解垂直流人工湿地(ICIE-VFCW)装置,研究了ICIE-VFCW对尾水的处理效果,并采用紫外-可见光光谱(UV-VIS)、凝胶过滤色谱(GFC),进一步探讨了ICIEVFCW强化脱氮机制.结果表明,ICIE-VFCW可提高系统对尾水中COD的去除,出水COD可稳定在30 mg·L~(-1)以下,全年、暖季、寒季COD平均去除率较普通垂直流人工湿地分别可提高10.16%、9.81%、11.22%.系统出水TN可维持在10 mg·L~(-1)以下,全年、暖季、寒季TN平均去除率较普通垂直流人工湿地分别提高13.72%、12.90%、16.17%.经过人工湿地处理后,污水中有机物的腐殖度、芳香度及相对分子质量(Mr)均有所下降,且ICIE-VFCW中Mr下降更为明显.湿地基质掺杂铁炭可促进尾水中大分子有机物转化为小分子,为微生物提供更多可利用碳源,从而提高脱氮效率.     

基于熵权的长沙市城市生态安全综合评估与预测

城市是一个社会-经济-自然复合生态系统,区域资源与城市自然系统是城市社会经济发展的重要基础和载体。城市生态安全评估是对未来的安全状态进行预测,以实现城市的可持续发展。文章以长沙市为例,在城市生态安全主要影响因素识别的基础上,应用PSR模型、熵权法等建立城市生态安全评估指标及计算方法,研究了长沙市近11年来生态安全的变化趋势。研究结果表明,1999-2009年间长沙生态安全的趋势由较不安全向较安全状态发展,生态安全值从25.4提高到60.7,人文环境响应是长沙生态安全改善的主导因素,资源环境压力,水土资源保持是限制长沙市生态安全的主要因素。     

游梁式抽油机底座断裂故障分析

对一起游梁式抽油机底座断裂故障进行了原因分析,并根据具体原因提出了相应的防范措施,以减少此类故障的发生概率,确保抽油机安全平稳运行。     

基于熵权的改进密切值法在水质综合评价的应用

将2003至2008年宁德市金涵水库水质监测值与地表水环境质量标准相结合,建立了环境样本矩阵,运用信息熵原理确定各指标的权重,并应用改进密切值法进行水质综合评价。结果表明：金涵水库从2003至2008年水质都是Ⅱ类以上,水质总体良好。该评价方法操作简便易行,结论切实可行,并可反映出各评价单元的优劣变化。     

模糊评判在岩质边坡稳定性评价中的应用

在工程实践中,影响岩质边坡稳定性的因素众多,不同因素的影响程度不相同,具有不确定性,因此选择合适的方法对岩质边坡稳定性进行评价尤为关键。本文采用模糊综合评判方法对岩质边坡进行稳定性评价,首先阐明了如何建立模糊评判体系以及权重和隶属度的确定方法,然后以某岩质边坡为实例,采用模糊评判方法对其稳定性进行了评价,结果表明模糊评判的结果与实际情况较为吻合,说明该方法真实、有效,具有一定的借鉴意义。     

装置级突发事故应急预案编制的思考与对策

结合石化企业装置生产特点,分析装置级突发事故应急预案编制中存在的不足和问题,并对应急预案编制的思路和处置对策进行了深入地探讨.