Food supply capacity study at global scale

The world population is expected to grow to 10 billion people in 2040, requiring food production at least to triple, as a combined result of population growth and dietary changes. In this study scenarios for food security are developed for 15 major regions of the world. Food production is calculated on a 1°x1° grid basis, using inputs from a digital data base containing soil, climatic, agronomic and demographic data. This allows us to study impacts of different production scenarios and their environmental side effects. Soil area data are derived from the digitized FAO soil map, considered to be representative for soil units on a 1°x1° grid; weather variables of 978 stations are allocated to the grid cells. Food production estimations are made with a simple crop growth module, a soil water balance and a soil nitrogen balance. Calculations are done on a grid basis, each grid cell being characterized by its suitability for arable farming or grassland, soil and climatic conditions and the availability of irrigation water. Results of Yield Oriented Agriculture (YOA) and Environment Oriented Agriculture (EOA) production scenarios on food self-sufficiency are presented. If we assume that there is no limit to transport of food across the globe, YOA allows the entire globe an affluent diet, while EOA allows only a moderate diet. For this scenario, regional self sufficiency indices vary widely: most regions can produce food required for an affluent diet, but not East, South and West Asia that account for 48% of the expected global population in 2040. Also Southeast Asia (9% of expected global population in 2040) and West and North Africa (10%) come close to the lower limit for food self-sufficiency. With EOA, only the former USSR, North and South America, Central and Southern Africa and Oceania can offer their future populations an affluent diet. Southern Asia will experience food shortages even under minimum food demand, and less affluent diets do not provide a solution. In this paper, attention is given to the methodology regarding soils, and to the uncertainty regarding soil and water in input data. Particularly soil suitability for agriculture for each of the grid cells has a large effect on model calculations, as it is a rather rough approximation. Knowledge of soils across the world shows important weaknesses with respect to the extent of coverage, extrapolation of point observations to grid cells, definition of soil characteristics compatible with crop models, and handling of preferential flow in soil profiles. We emphasize the need for digitized, reliable and readily available natural resource information in the fields of soil surveys, climatology, irrigation water availability, land use and land cover. The ultimate goal of the approach is not to predict the future of global agriculture, but to allow decision makers to compare various scenarios for food self-sufficiency, and to raise awareness regarding issues related to food security. In spite of the above-mentioned shortcomings in basic data, it is demonstrated that it is possible to develop the required scenarios now, instead of having to wait on more reliable soil information.     

Hydraulic habitat composition and diversity in rural and urban stream reaches of the North Carolina Piedmont (USA)

The differences between urban and rural streams regarding hydrological process, channel morphodynamics and ecosystem functioning have been highlighted by a number of studies in recent decades. The need to understand lotic ecosystem functioning in these environments at scales relevant to individual organisms has led to research focusing on hydraulic composition and structure over small areas of channel bed. In this study we map and analyze the hydraulic biotope composition of two urban and two rural stream reaches in the North Carolina (USA) Piedmont to determine if urban flow regimes and attendant channel modification processes might translate into important differences in hydraulic environment, and if so, what those differences are. Hydraulic biotope assemblages were found to vary only moderately in diversity per unit stream length between sites, but were distinctly different in composition. One important control on the differences between rural and urban streams was found to be the localized incision of urban channels into bedrock and saprolite. Resistant rock outcrop in the beds of urban streams creates rapid and riffle biotopes and long stretches of upstream pool habitat by impoundment. Urban reaches were found to be more homogeneous than rural reaches in hydraulic composition and were dominated by pools. Rural reaches, characterized by copious sandy alluvium in the bed, were dominated by runs or glides. Quantitative differentiation of biotopes based on four hydraulic indices generally yields coherent associations, although these may vary in content. Comparisons between hydraulic and biotic diversities suggest relationships favoring biotic functional group aggregation over species richness‐based indices of diversity. Because the majority of published hydraulic diversity analyses are based on coarse‐bed streams, further study of hydraulic diversity in streams with finer substrate is likely to be beneficial. Copyright © 2008 John Wiley & Sons, Ltd.     

基于运动学分析的装甲车辆驾驶操纵舒适性研究

运用人体运动学理论和方法，以国军标和相关国标为依据，建立了装甲车辆驾驶员的运动学模型，并以某型坦克为例，对装甲车辆驾驶舱操纵装置的操纵舒适性进行了分析，其结果可为装甲车辆驾驶舱操纵装置的合理布局提供借鉴．     

辽河流域健康评价指标体系初探

辽河流域生态脆弱,河流污染严重.本文基于辽河现状,从辽河流域、河流廊道、栖息地3个尺度,确定评价指标体系,采用熵权法和集对分析不确定性理论,对辽河流域健康指标进行评价分析确定,为辽河水生态保护和修复提供决策依据.     

浅析陶瓷产品的工艺适合性选择途径

随着经济发展程度的不断提高,陶瓷产品在人们的生活中越来越占据重要位置。我国虽然是陶瓷产品的生产大国,却在生产中一些工艺环节上存在工艺相对落后、生产效率不高等问题。因此,能否为陶瓷生产企业寻找一种更为适合的陶瓷工艺选择途径,是我国陶瓷产品迈向更高层次的关键。本文将结合产品设计相关理论浅析说明。     

Invertebrate communities in Compensation Creek,a man‐made stream in boreal Newfoundland: The influence of large woody debris

Benthic invertebrate communities were examined in Compensation Creek, a man‐made stream in south‐central Newfoundland, Canada. Samples taken in September 2006 and September 2007 from large woody debris (LWD) were compared with samples from benthic environments to determine whether LWD supported a more diverse and abundant invertebrate community. Benthic habitats in a nearby natural stream were also sampled. Taxa composition was similar between the man‐made and the natural stream, highlighting successful colonization for the majority of taxa. Within Compensation Creek, taxa richness was higher in benthic habitats than on LWD, likely influenced by the successional age of the stream and surrounding habitat. The more complex benthic substrate provided refugia and allowed for the accumulation of fine detritus as a food source. Scrapers were almost completely absent from LWD and collector‐gatherer abundance was greater in the benthos. Collector‐filterer abundance was more than six times greater near the pond outflow than farther downstream when discharge was high, but abundances were almost equal when discharge was reduced. Riparian vegetation has not fully established around the man‐made stream, whereas it is overhanging and extensive at the natural stream, leading to more leaf‐litter input for shredders. As the morphology of Compensation Creek changes, the invertebrate community will continue to develop and likely increase utilization of accumulated detritus at LWD. Copyright © 2009 John Wiley & Sons, Ltd.     

神东矿区矿井水水化学特征及其灌溉 适宜性评价

矿井水水化学特征决定着其处理工艺及其成本。以神东矿区为研究对象,采集了12组矿井水样品进行测试,采用统计分析、Piper三线图、Gibbs图、各离子间相关关系,确定了其水化学特征及其影响机制。结果表明,矿井水样品的pH值为7.64~8.48,TDS为275.13~3 090.14 mg/L,F^-浓度最高为6.75 mg/L,绝大部分矿井水为高氟、高矿化度水;在空间上呈现了西北高、东南低,随埋深增大,TDS和F^-浓度逐渐升高的趋势;主要水化学类型为HCO₃·SO₄·（Cl）-Na及HCO₃·SO₄·（Cl）-Na·Ca。煤层埋深较浅,易接受补给的矿井水主要受岩石风化控制,反之,主要受浓缩作用控制。同时矿井水还发生了阳离子反交换作用。其用于灌溉的盐碱害较严重,综合EC值、SAR以及钠百分含量指标,判定矿井水大部分为不适合灌溉用水。研究为后期制定矿井水处理工艺及高效利用方案提供参考。     

河流地貌多样性内涵、分类及其主要修复内容

针对河流修复中对河流地貌重视不够及多样性认识不深等问题,解析了河流地貌多样性的内涵及与河流栖息地的统一性,将常见河流地貌类型分为3种河谷地貌、38种河床地貌、15种水流形态以及人工活动形成的地貌类型,并提出基于过程的修复策略来修复河流地貌。在修复河流地貌时,首先应充分考虑形成河流地貌的水陆域过程,识别泥沙源时空分布,并重点修复深槽—浅滩序列。     

风景旅游区生态风险及适宜性评价

文章通过水土流失敏感性、植被与生物多样性重要生态功能区保护、防洪排涝敏感性以及地质灾害敏感性分析,综合得出风景旅游区范围内生态控制性方案,并对五当召风景旅游区生态风险适宜性进行了评价。     

楠溪江干流香鱼栖息地水生态调查分析

香鱼是楠溪江较为名贵且对环境敏感的一种鱼类,由于人类活动影响,香鱼栖息地遭到破坏,导致香鱼数量急剧减少。为进一步开展楠溪江香鱼栖息地的水生态保护与修复工作,本文对楠溪江香鱼栖息地水质及着生藻类进行了现场调查与分析,结果表明:香鱼产卵期的产卵场及育肥期的育肥场水质相对较好,能为香鱼的产卵、育肥提供较好的水质环境;上溯期的中游产卵场河段及下游感潮河段水质均较差,不利于香鱼从下游河段向育肥场迁移。产卵场和育肥场着生藻类生物量丰富,以硅藻为主,有利于香鱼的产卵和育肥。为促进楠溪江香鱼栖息地的保护与修复,针对楠溪江下游感潮河段开展水环境综合治理工作,提出了重点关注TN的削减的建议。