防灾减灾新形势下中国高风险地区综合气候变化风险防范战略分析

从综合气候变化风险防范的紧迫性入手,简要阐述气候变化导致了自然灾害风险加剧,提出中国高风险区的综合气候变化风险防范的工程与非工程性措施,并就东中西部综合风险防范提出建议。     

果树调亏灌溉技术的机理与实践

农业节水是中国农业可持续发展过程中的一项重大课题，节水灌溉技术是其中的一条有效途径。该文在节水灌溉技术基础上，根据果树生长的生理特点，提出了在特定时段控制灌溉次数和灌溉水量，让植株主动承受一定的水分应力，之后充分供水，使果实迅速膨大，达到提高果树产量和果品品质，又节约大量灌溉水量目的的果园灌溉管理新技术——调控亏水度灌溉（RDI）。田间试验结果验证了RDI的功效。并论述了实现果园RDI技术的过程，展望了中国发展RDI 技术的前景。     

黄瓜霜霉病菌烯肟菌酯敏感基线的建立及其室内抗药性风险评估

为研究黄瓜霜霉病菌对烯肟菌酯的敏感性及室内抗药性风险,采用叶碟保湿法测定了52株黄瓜霜霉病菌对烯肟菌酯的敏感性。结果表明52个菌株的EC50(抑制中浓度)差异较小,平均EC50为(0.010 1±0.003 1)μg/mL。黄瓜霜霉病菌对烯肟菌酯的敏感性频率分布呈连续单峰曲线,接近正态分布,没有出现敏感性下降的抗药性群体,这些病菌均为烯肟菌酯野生敏感菌株,因此可以采用其平均EC50作为黄瓜霜霉病菌对烯肟菌酯的敏感基线。室内药剂驯化和紫外线诱变试验,获得了10株黄瓜霜霉病菌对烯肟菌酯不同抗性水平的突变体,其EC50为1~5μg/mL,抗性指数为80~500倍,抗药性稳定,致病力、适合度、竞争力与亲本菌株相比没有明显差异,或优于亲本菌株。室内抗药性风险评估表明,黄瓜霜霉病菌对烯肟菌酯具有较高的抗药性风险,预示田间自然情况下抗药性菌株可能形成优势菌群而导致药剂防治失败的潜在风险。     

Wolves, elk, willows, and trophic cascades in the upper Gallatin Range of Southwestern Montana, USA

We summarized the status of wolves (Canis lupus), elk (Cervis elaphus), and woody browse conditions during the 20th century for the upper Gallatin elk winter range in southwestern Montana, USA. During this period, wolves were present until about the mid-1920s, absent for seven decades, and then returned to the basin in 1996. A chronosequence of photographs, historical reports, and studies indicated willows (Salix spp.) along streams became heavily browsed and eventually suppressed following the removal of wolves, apparently due to unimpeded browsing by elk. However, after wolf establishment in 1996, browsing intensity on willows lessened in some areas and we hypothesized that, at both a landscape and fine scale, browsing pressure reflects terrain configurations influencing predation risk (nonlethal effects), in conjunction with lower elk densities (lethal effects). We measured browsing intensity and heights of Booth willow (S. boothii) along 3000 m reaches of the Gallatin River and a tributary to examine the potential influence of wolf/elk interactions upon willow growth. Where the Gallatin Valley is relatively narrow (high predation risk), willows began releasing in 1999 and by 2002 were relatively tall (150–250 cm). In contrast, willow heights along a wider portion of the Gallatin Valley, along the open landscape of the tributary, and an upland site (all low predation risk) generally remained low (<80 cm). We identified terrain and other features that may contribute to the perceived risk of wolf predation, by elk for a given site. Although alternative mechanisms are discussed, changes in willow communities over time following wolf removal and their subsequent reintroduction were consistent with a top-down trophic cascade model involving nonlethal and possibly lethal effects. If similar top-down effects upon vegetation hold true in other regions of North America and other parts of the world where wolves have been extirpated, wolf recovery may represent a management option for helping to restore riparian plant communities and conserve biodiversity.     

基于风险与效益模型的政府农业科技投入范围界定

在分析农业科技研发层次与演化流程的基础上,提出了不同研究阶段的农业技术类型和特征,构建了农业科技研发投入风险与效益模型,揭示了政府农业科技投入领域的选择行为,并以此界定了农业科技投入的合理范围。     

基于景观格局原理的土地规模化整理潜力评价方法

土地整理目的主要包括增加土地数量、提高土地质量和生产效率等,土地规模经营是提高土地生产效率的主要方法之一,也是现代规模农业发展的要求。该文探讨利用地形指标,景观丰度指数、斑块方度指数、景观集中度指数等景观格局指标定量评价土地规模化整理潜力的方法,为区域土地整理规划提供科学依据。并以喀斯特山区耕地整理为例,应用GIS（geographic information system）技术定量分析了广西喀斯特山区耕地规模化整理潜力的差异。结果表明,广西都安县大部分位于石山区乡镇的耕地规模化整理潜力指数均很低,而南部河谷区乡镇的耕地规模化整理潜力指数较高,河谷平坦区的耕地规模化整理潜力指数为0.85,喀斯特峰丛峰林山区为0.17,前者为后者的5倍。表明土地规模化整理潜力受到土地资源空间格局和地形格局的共同制约,不同地形和土地资源格局条件下,区域土地规模化整理潜力之间差异显著。     

陕北粮食生产潜力及土地人口承载力研究

在光温生产潜力计算的基础上,经过降水、土壤肥力和土壤质量等自然因素的订正,分析了陕北的土地生产潜力和粮食生产潜力。通过对陕北主要粮食作物产量分析,采用产潜比增长速度法预测了2010年和2020年的粮食产量,并据此计算2010年和2020年的潜在人口最大承载量,提出了陕北建立稳定协调可持续发展的人地关系的关键。     

The Application of Relevant Homology in the Unified Representation of Electromagnetic Potentials and Gauge Transformation

Electromagnetic potentials and gauge transformation are derived for non-cloSedexterior differential forms with the help of relevant homology.Since de Rham ccahomology is sure-ly a relavant homology. potentials for both closed and non-closed forms and the gauge transforma-tion ean be unified in terms of relavent homology.     

纳米氧化锌对绿豆芽生长的影响

深入研究不同类型的纳米颗粒对不同植物物种具有的独特效应,可提高有关纳米物质对植物安全与风险的认知水平。为了对纳米物质生物效应的深入评估提供科学依据,测定了室温（25℃）浸种培养后绿豆芽的叶绿素、过氧化物酶活性、根长、茎长、鲜重、干重、蛋白质等生理指标及其可食部分的锌含量。结果表明,nano-ZnO和Zn2＋在较高浓度（50~1000mg.L-1）时均可抑制植物的生长,呈现出一定的植物毒性;相同浓度时,nano-ZnO较Zn2＋更有利于绿豆芽的生长和其可食部分锌的富集。最有利于绿豆芽生长和锌富集的nano-ZnO浓度为50mg.L-1,而Zn2＋浓度则为20mg.L-1。在促进生长的浓度范围内（0~50mg.L-1）,绿豆芽可食部分锌含量均小于国家食品锌标准含量值（20mg.kg-1）。可见,nano-ZnO可尝试应用于绿豆芽的农业生产活动,但在此之前须进一步开展其存在的环境、生态与人体健康风险研究。     

Potential longevity (Ki) of malting barley (Hordeum vulgare L.) grain lots relates to their degree of pre-germination assessed through different industrial quality parameters

Barley (Hordeum vulgare L.) grain germination is required to perform the malting process. Maintenance of barley seed viability during storage is crucial for the malt industry; and modern cultivars are bred for rapid grain dormancy release after physiological maturity. Low dormancy level combined with rain close to harvest induces pre-germination/pre-harvest sprouting damage. Pre-germination might not affect viability in the short term after harvest, but it could reduce potential longevity (K_i) of a barley seed lot. K_i value is inherent for each barley lot; however, its determination is time-consuming which precludes its assessment at an industrial scale. In this study we sought quantitative relationships between K_i and the pre-germination degree of barley grain lots, assessed through quality tests routinely performed by malthouses [Falling Number (FN), α-Amylase Activity and Carlsberg]. Field pre-germinated lots from one old barley cultivar (Quilmes Palomar) and artificially pre-germinated lots from major varieties currently grown in Argentina were used. Associations between K_i and values obtained from all quality tests analysed were found for Q. Palomar. However, FN was the parameter that yielded the best and simplest explanation of K_i variability. A significant positive linear K_i -FN relationship was also obtained for each modern barley cultivar.