农业气象灾害对江苏淮北地区冬小麦产量的影响分析

本文用拉朗日插值法推算江苏省淮北地区冬小麦在无农业气象灾害条件下从1960－2000年41年的期望产量，并用用S软件建立气象灾害对冬小麦产量影响的逐步回归模型，分析了各类农业气象灾害对产量的影响。对指导淮北地区有针对性地防御农业气象灾害，降低其对冬小麦产量的 影响有重要的实际意义。     

近百年我国的异常暖冬与冷冬

根据１９５１年以来１６０站观测资料对我国冬季气温进行了ＥＯＦ分析，发现全国绝大部分区域的冬温变化有很好的一致性。因此，冬季平均气温能较好反映全国的整体变化特征。用全国气温等级图资料订正了１９１０年至１９５０年全国平均气温，用北京和上海２站的平均气温订正了１８８０年至１９１９年平均气温。对１８８０年以来的全国平均冬季气温序列取１０ａ一遇标准，确认出近１１８ａ中共有１３次异常暖冬和１０次异常冷冬。还分析了西伯利亚高压和全球性的温度变化对我国冬温变化和异常的影响     

Studded and unstudded winter tires in fatal road accidents in Finland

Objective: The aim of the study was to compare the safety effects of studded and unstudded winter tires based on fatal road accidents.

Methods: The data included 958 road accidents involving a passenger car or van that occurred in Finland from November to March between 1997 and 2012.

Results: Comparing the proportions of winter tire type in accidents and in general traffic showed that the overall effect of tire type on the number of accidents was not significant, although studded tires reduced fatal accidents by 10–15%. Compared to unstudded tires, studded tires reduced accidents significantly only on bald ice in 2005–2012. Drivers using unstudded tires were more experienced and their profession was more frequently related to driving. In addition, the vehicle age was lower for vehicles with unstudded tires. On the other hand, the state of repair was less pertinent for unstudded than for studded tires. These confounding factors offset their effects to some degree.

Conclusions: The risk of fatal road accidents in winter between studded and unstudded tires does not differ significantly. However, the accident risk has recently been substantially higher on bald ice for unstudded than for studded tires. The magnitude of this risk difference is difficult to determine without specific information on exposure by road surface.     

应用ARID CROP模型对中国黄淮海地区冬小麦气候生产力的数值模拟研究

应用ＡＲＩＤＣＲＯＰ模型对黄淮海地区冬小麦气候生产力进行了数值模拟研究,给出了该地区冬小麦气候生产力Ｙｑ分布图,继而研究了水分保持最适状况时的光温生产力Ｙｗ分布状况,在此基础上给出了水分增产力Ｑ（Ｑ＝（Ｙｗ－Ｙｑ）／Ｙｑ）分布图。研究表明,黄淮海地区冬小麦气候生产力变幅在３７５０～９７５０ｋｇ／ｈｍ^２之间,总的趋势北低南高,黑龙港地区出现了一个３７５０ｋｇ／ｈｍ^２的低值区。水分是黄淮海北部地区冬小麦气候生产力的一个重要限制因子,当水分完全适宜时,南部淮河流域冬小麦气候生产力仅可提高５％～１０％,而黄淮海北部地区气候生产力则可提高７５％～１００％。用黄淮海地区冬小麦高产记录与生产力模拟值进行了对比分析,表明用ＡＲＩＤＣＲＯＰ模型对该地区冬小麦气候生产力进行研究是可行的,该研究为引黄灌溉提供了一定的理论依据。     

太湖水体溶解营养盐(N、P、Si)的冬、夏二季变化特征及其与富营养化的关系

先后于冬季(2003年1月)和夏季(2003年7月)对太湖水体溶解营养盐的组成进行了调查,分析了营养盐在湖水中的分布规律,初步探讨了太湖浮游植物营养盐限制因子的季节变化特征。结果显示:太湖溶解无机氮、磷、硅夏季比冬季略高一点,主要来自流域外源输入和湖泊内源释放,分布趋势受人为活动大小和湖泊自身特点的影响。     

冬小麦根系生长与土壤水分利用方式相互关系分析

１９９５～１９９６年在中国科学院栾城农业生态系统联合站布置了冬小麦水分试验，在土壤连续干旱条件下考察了冬小麦返青至成熟阶段根系生长和土壤水分利用方式。给出并验证了可用于分析二者相互关系的定量模型。根据以下两点分析了作物利用土壤水分特征：①将土壤含水量开始降低时间视为吸水峰到达某一深度时间；②吸水峰下达到某一土层后，土壤含水量即随生育进程以指数形式逐渐降低。愈接近地表的土层，根系分布量愈大，根系日增长率在抽穗期最大，至扬花期根量及根深达最大值，根系吸水范围和深度基本取决于营养阶段根系生长发育状况。返青时，根系已下扎到１ｍ，根系生长峰与吸水峰基本同步下移，根系下扎到某一土层后继续生长发育，直至土壤有效含水量只剩４０％～２０％时为止。根系下扎虽深达１８０ｃｍ，而且下层根系吸水功能较强，有效水量较大，但终因根系分布量太少，致使作物利用水分的土层深度只达１２０ｃｍ，吸收的水量大多来自０～６０ｃｍ土层。在土壤连续干旱条件下，土壤水分不足亦是制约根系吸水功能的一个重要因素。在作物利用土壤水分初期，根系吸水速率最大，随着土壤含水量逐渐减少，根系吸水速率随之降低。土壤中有效含水量比例在０８以上，根系吸水速率大致以线性关系大     

黄土塬区旱作冬小麦增产潜力研究

在长期冬小麦潜势试验和肥料试验的基础上 ,建立了作物光温水肥产量模型 ,从光温生产潜力、旱作产量潜势、现阶段施肥水平下光温水肥产量潜力和目前试区产量现状共4个层次 ,对黄土塬区旱作冬小麦的增产潜力进行了分析。结果指出 ,目前黄土塬区冬小麦实际产量仅达到了光温潜力的41 6 %、旱作产量潜势的49 3 %、试区施肥水平下光温水肥产量潜力的78 6 %。因此 ,采用合理施肥方式和加强田间管理 ,黄土高原塬区旱作冬小麦还有较大的增产潜力。     

Experimental analysis of a nitrogen removal process simulation of wastewater land treatment under three different wheat planting densities

Nitrogen contaminant transport,transformation and uptake simulation experiments were conducted in green house under three different planting density of winter wheat.They were Group A,planting density of 0.0208 plants/cm^2,Group B,0.1042 plants/cm^2,and Group C,0.1415 plants/cm^2.The capacity and ratio of nitrogen removal were different on three kinds of conditions of wastewater land treatment.From analysis of wastewater treatment capacity,wastewater concentration and irrigation intensity for Group C were suitable and nitrogen quantity added was 2 times of that for Group B,2.6 times for Group A while nitrogen residue was only 7.06%.Hence,wastewater irrigation and treatment design with purpose of waste water treatment should select the design with maximum capacity,optimal removal ratio and least residue in soil,which was closely related to crop planting density,crop growth status and also background nitrogen quantity in soil.     

Simulating canopy stomatal conductance of winter wheat and its distribution using remote sensing information

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鲁西北棉田冬季蔬菜越冬种植技术

根据鲁西北棉区冬季蔬菜越冬种植的自然条件和生产实践经验，本文阐述了适合棉区推广的棉田蔬菜越冬种植模式、操作技术规程、技木要点及其效益对比．