基于分形理论的大中型拖拉机产量预测

大中型拖拉机产量是一个复杂的非线性系统。为了探讨大中型拖拉机产量的变化规律及趋势预测,在分析分形理论原理和大中型拖拉机产量时间序列分形特性的基础上,构建了R/S分形模型,该模型具有较高的拟合度。最后,应用该模型预测了河南省2013-2015年大中型拖拉机的产量,可为农机企业调整产品结构和河南省农机部门制定农机动力发展规划提供参考。     

中国土壤系统分类土系描述的难点与对策

土系是土壤系统分类的最基层单元,我国现有土系约3 000个,距约3万个的估计总量还有巨大差距,因此土系建设在未来相当长时间内仍将是我国土壤系统分类研究和土系建设的一个重点。土系描述是土系建设最为重要的一环,是土系所有信息的直观具体展现,为确保土系描述的质量,国家科技基础性工作专项"我国土系调查与《中国土系志》编制(2008FY110600)"初步制订了土系描述标准,但其在描述规范上还存在一些问题有待明确和解决。为此,本文基于土系描述标准的介绍,剖析我国土系描述中存在的主要问题和产生原因,并提出相应对策,旨在进一步完善土系描述标准的科学性、规范性、全面性和系统性,提高我国土系描述的质量。     

诱发籼稻早熟同型系的研究 Ⅰ.早熟同型系的发生及其规律

在同一籼稻类型品种中,早熟同型系发生率4年间基本类似(分别为1.41%、1.37%、1.42%、1.64%),但在不同生态类型品种中早熟同型系发生率则不相同:早熟种为0.73%,中熟种为1.51%,迟熟种为1.97%.系谱亲缘相同的品种,其早熟同型系发生率各自相似;系谱不同的品种则相反.早熟同型系发生的基本规律与特点:1.早熟同型系发生的基础是抑制的表现型;2.早熟同型系的发生与原品种的生育期密切相关;3.出现早、晚熟双向熟期变异的同时,发生株型、叶型等性状的平行变异;4.早熟同型系的发生有不平衡性.早熟定向诱变育种,根据同型系系列的基本原理,只要准确地了解和掌握种、属类型、品种生态特性和品种系谱亲缘3个方面,就能预估诱变后代产生早熟同型系,进行早熟定向诱变,培育新品种.     

叶尔羌河年径流量动态变化趋势分析

建立了叶尔羌河卡群站年径流量（１９５４～１９９７ 年）的时间序列模型,该模型可用于年径流量预测。根据分析结果,卡群站年径流量具有不显著的递增趋势和明显的周期变化,同时具有一定的随机性     

The potato genetic resources held in trust by the International Potato Center (CIP) in Peru

Summary Potatoes account for about half of the world's annual output of all roots and tubers, and since the early 1960s, the increase in area planted in developing countries has been higher than for any other major food crop. Annual world production currently totals 274 million tons on 18 million hectares, with China and India accounting for 22 percent of this total. In less than a generation, most of the world's potatoes will be harvested in Asia. Africa, or Latin America, where the potato is becoming an increasingly important source of food and its cultivation provides rural employment and income for the growing population. The rapid emergence of processing facilities for the fast food industry, and the indirect influence of improved rice and wheat irrigation systems have also contributed to the expansion of potato production in Asia. The demand is strongest for processing quality potatoes that supply the fast food chains in large urban concentrations where processed potato products fetch top prices. Such increasing demand is putting strong pressure on national and international breeding institutions to produce high quality processing varieties well adapted to the wide array of agro-ecological conditions, in South East Asia in particular. The lack of adequate seed systems in this region is the single most important impediment to the expansion of the cultivation of the crop. Unfavourable agro-ecological conditions interfere with the production of high quality seed in most Asian potato growing areas, and the availability of high quality seed of the right quantity at the right time remains the most consequential bottleneck to efficient potato production. The seed issue is also the principal problem of potato cultivation in the traditional potato growing areas of Central and Eastern Europe. A review of “the development of integrated systems for large scale propagation of elite plants using in vitro techniques” with specific focus on “potato seed production by tissue culture” is therefore very timely. It provides a platform for analysis and discussion of solutions for some of the most common seed problems facing the potato industry in many parts of the word. All efforts to improve the potato crop and to solve the associated seed problems begin with the right choice and use of the available genetic resources. Resistance to certain pests and diseases has a direct bearing on the success of a seed program. Multiple virus resistance, in particular, would ensure a halt to seed degeneration caused by an accumulation of viruses and thus greatly prolong the ability of seed producers and ware potato growing farmers to grow their crops at great economic benefit. This paper will therefore deal with the current status of the World Potato Collection held in trust by the International Potato Center (CIP) in Peru by presenting up-to-date information on its classification, phytosanitary status and availability of the genetic material and its evaluation data to the breeders worldwide.     

近50年来霍林河流域径流量演变规律研究

霍林河是松嫩平原西部地区科尔沁、向海和查干泡湿地的重要补给水源,选取流域内3个代表站的径流实测资料,对50年来流域年径流量、雨季径流量、枯季径流量和基流径流量的演变规律进行分析。径流量年均序列的db3小波函数多分辨率分析表明,期间流域径流量总体呈下降趋势;“距平累积法”将径流量序列分为3个阶段,1965年以前径流量偏多阶段,1965~1985年的偏少阶段和1985年以后的偏多阶段;1985年以后流域径流量较强的增长趋势变化用Mann-Kendall非参数检验法检测达到突变水平,增长突变发生在1985~1990年;Morlet小波分析表明,不同类型径流量主要存在3个尺度的周期变化,预测在未来几年流域将逐渐进入较大尺度的枯水期之下的较小尺度的相对丰水期。     

Quantifying Spatiotemporal Patterns of Urban Land-use Change in Four Cities of China with Time Series Landscape Metrics

This paper provides a dynamic inter- and intra-city analysis of spatial and temporal patterns of urban land-use change. It is the first comparative analysis of a system of rapidly developing cities with landscape pattern metrics. Using ten classified Landsat Thematic Mapper images acquired from 1988 to 1999, we quantify the annual rate of urban land-use change for four cities in southern China. The classified images were used to generate annual maps of urban extent, and landscape metrics were calculated and analyzed spatiotemporally across three buffer zones for each city for each year. The study shows that for comprehensive understanding of the shapes and trajectories of urban expansion, a spatiotemporal landscape metrics analysis across buffer zones is an improvement over using only urban growth rates. This type of analysis can also be used to infer underlying social, economic, and political processes that drive the observed urban forms. The results indicate that urban form can be quite malleable over relatively short periods of time. Despite different economic development and policy histories, the four cities exhibit common patterns in their shape, size, and growth rates, suggesting a convergence toward a standard urban form.     

泾河流域近60年降水演变规律

对泾河流域11个气象站(1960～2000年)的降水量资料,通过标准化、滤波等方法处理简化了研究对象。采用数理统计方法对降水时间序列进行分析,得到泾河流域降水演变的规律,春季有5a、8a的显著周期,夏秋有准7a的周期振荡,冬季有4a、6a的短周期,还有17a左右的长周期。同时,用流域内平凉站近60a(1942～2000年)的序列进行对比分析,发现演变规律基本一致。利用上述规律对2001～2003年流域内降水进行试验性拟合预测,结果与实况基本符合,并显示21世纪前10a泾河流域秋雨量有可能改变上世纪末持续偏少的态势,呈偏多趋势。     

小干沟电站上游补偿调节水库调度

本文运用时历法绘制了小干沟电站上游补偿调节水库的调度图。用随机动态规划法对该补偿调节水库进行了优化调度计算,绘制了该水库的调度图,并提出了有关调度建议,对该电站的实际运行具有指导意义     

小麦理想株型研究 Ⅰ.小麦株高梯度系列的株型、产量及品质性状的变化研究

对小麦回交转育所得七个株高梯度系列的35个系统的研究结果表明,矮秆品种高化共同表现在第4,5节间及3,4相对叶间距的增长,这对减少郁蔽有利,籽粒产量及千粒重均有显著增加的趋势,收获指数仍较高,品质也不致下降,在矮×高的矮秆分离群体中选相对较高的植株有利;高秆矮化共同表现在第4节间及3,4相对叶间距缩短,品质性状可得到一定程度改良,回交使高秆品种矮化有效。提出了相对株型的概念,并认为下4节间总相对长、相对叶间距等可作为株型识别的指标。