基于几何语义知识的冬小麦自动分类

【研究目的】为了实现遥感影像的作物自动分类，并探索空间信息在分类中作用，【方法】本文提出结合光谱和空间信息的作物分类方法。首先，借助光谱信息实现地物初始分割，然后以目标作物历史空间分布为语义约束，根据隶属度提取目标作物。最后，在多时相遥感影像条件下，以冬小麦为目标作物进行了方法的验证，【结果】结果显示，本文方法可实现冬小麦自动提取与识别，总体精度为95.33%，Kappa系数为0.90，可满足农情监测的实际需求。另外，在单时相遥感影像条件下，本文结合几何语义知识的作物分类精度也达到了较高水平。【结论】相对于遥感影像单一光谱信息的分类方法，本文方法利用了作物空间信息，不仅能满足精度要求，还实现了分类的自动化，对工程化应用具有一定的参考价值。     

互叶白千层扦插苗质量评价及分级标准

对四川犍为地区引种栽培的互叶白千层扦插苗进行抽样调查,采用相关性分析、“x¯±s”法和主成分分析法对其苗木质量进行评价和苗木分级研究。结果表明:评定互叶白千层苗木质量可以苗高(H)、地径(D)和全株生物量作为表型指标,结合主根数量,并辅以根系长度作为辅助参考综合评价指标。提出了以苗高和地径作为该树种苗木分级的质量指标,并得出互叶白千层扦插苗的3级分级标准,Ⅰ级苗木:苗高>17.66 cm,地径>1.98 mm;Ⅱ级苗木:苗高为11.48~17.66 cm,地径为1.36~1.98 mm;Ⅲ级苗木:苗高<11.48 cm,地径<1.36 mm。可为互叶白千层苗木分级和筛选提供一定的理论依据。     

北京地区雨燕科3种雨燕羽毛的扫描电镜观察

为系统地研究北京地区雨燕科3种雨燕的羽毛特点,给雨燕科的保护、分类研究积累资料,笔者对北京地区分布的雨燕目(Apodiformes)雨燕科(Apodidae)的白腰雨燕(Apus pacificus)、普通楼燕(Apus apus)、白喉针尾雨燕(Hirundapus caudacutus)主要类型羽毛进行微观结构对比观察。试验流程为:鸟类标本取样前再鉴定、确定采样位置、取样、样品脱脂、超声波清洗、自然干燥、离子溅射喷金及扫描电子显微镜观察。结果表明:飞羽、尾羽和体羽主要有钩羽小枝和无钩羽小枝构成;有钩羽小枝和无钩羽小枝相互啮合形成坚实的羽面来减少飞行阻力。3种鸟类羽毛的飞羽羽小轴表面纹饰、绒羽节点形状可以作为属间分类重要特征,飞羽、尾羽及体羽其他特征参数可以作为参考。     

福建地方梨资源果实性状多样性分析及其数量分类研究

对保存的50份福建省地方梨资源的26个果实性状进行数据采集,分析果实性状的分布频率、变异系数和Shannon-Weaver指数,应用Q型和R型聚类分析法对种质和性状进行分类,并基于果实性状进行主成分分析。结果表明:(1)所收集种质的果实描述性状多样性丰富,以果点明显、果锈多、果面粗糙、果肉脆、风味酸甜、无涩味、果心小和成熟期为9月的种质居多,分别占92%、52%、54%、50%、50%、70%、54%和80%。(2)数量性状中维生素C含量变异系数(67.60%)最大,其次为可滴定酸含量(48.26%)、糖酸比(42.22%)和固酸比(41.14%)。(3)描述性状Shannon-Weaver指数范围0.324～1.660,其中颜色和形状较高,多样性最丰富,而数量性状Shannon-Weaver指数范围达1.698～2.074,表现出更丰富的多样性。(4)Q型聚类分析在欧式距离为14.71时将供试种质分为5个组,组内具有一定的特征,组间存在差异,但并未发现按地域聚类的趋势;R型聚类分析在相关系数1.236处将果实性状聚为5组,多数性状间表现两两相关,部分性状间逻辑相关性明显。(5)主成分分析发现前10个主成分反映86.545%的贡献率,各性状贡献率较为分散,性状变异具有多向性;第1主成分的正向增长有利于提高果实内在品质,而第2、4主成分的正向增长有利于提高果实外观品质,第3主成分负向增长有利于增大果实大小。     

新疆土壤侵蚀类型图的编制研究

本文根据新疆水土保持规划任务要求，对新疆土壤侵蚀类型图进行了研究编制，采用卫星遥感技术，并结合气候，水文，地形，地貌，植被，土壤等诸多影响土壤侵蚀类型和强度的资料及因子图，进行研究判读，垒置，野外考察核定，用计算机技术和先进的技术设备完成了１／１００万的新疆土壤侵蚀类型图和土壤侵蚀数据库。     

基于图像处理的作物营养诊断研究进展

近年来，随着农业化肥滥用问题的日益突出，图像处理技术在作物营养诊断上的应用研究越来越多。通过对作物营养诊断研究背景的阐述，指出图像处理技术在作物营养诊断上应用的重要意义，介绍作物图像营养诊断研究的总体情况和基本思路，论述作物图像采集、图像预处理、特征提取与优化、分类识别4个环节所用技术方法以及取得的成果，并分析作物图像营养诊断方面存在的问题。     

种子科技档案在农业生产中的地位及作用

农业科技档案,是创造人类文明的实践记录,是农业科技资源的一种储备形式,它是国家的宝贵财富,它的潜能一旦转化为生产力,就可以创造出巨大的物质财富。     

Poisson Voronoï tiling for finding clusters in spatial point patterns

Abstract

In forest stand mapping a delineation of spatial compact clusters of trees with similar attributes can improve inventory accuracy and growth and yield predictions. To this end a Poisson Voronoï tiling (PVT) for identifying and delineating clusters (features) in spatial point patterns is proposed. PVT operates on the assumption that the point density in clusters is higher than that outside the clusters. A spatial domain of an observed point pattern is tessellated repeatedly into k (random) Poisson Voronoï cells. An average EM-based likelihood of feature based on observed cell point densities is computed for each point and location of interest. Points and locations of interest are then classified by maximizing a classification likelihood. PVT avoids the need to specify the number of clusters. In a direct comparison with a non-parametric maximum profile likelihood procedure, and a smoothed version of the same, PVT performed well on two artificial point patterns with known feature domain and points, and on two spatial point patterns of first returns from a forest lidar survey on Vancouver Island, British Columbia, Canada.     

Transitions in forest fragmentation: implications for restoration opportunities at regional scales

Where the potential natural vegetation is continuous forest (e.g., eastern US), a region can be divided into smaller units (e.g., counties, watersheds), and a graph of the proportion of forest in the largest patch versus the proportion in anthropogenic cover can be used as an index of forest fragmentation. If forests are not fragmented beyond that converted to anthropogenic cover, there would be only one patch in the unit and its proportional size would equal 1 minus the percentage of anthropogenic cover. For a set of 130 watersheds in the mid-Atlantic region, there was a transition in forest fragmentation between 15 and 20% anthropogenic cover. The potential for mitigating fragmentation by connecting two or more disjunct forest patches was low when percent anthropogenic cover was low, highest at moderate proportions of anthropogenic cover, and again low as the proportion of anthropogenic cover increased toward 100%. This fragmentation index could be used to prioritize locations for restoration by targeting watersheds where there would be the greatest increase in the size of the largest forest patch.     

Assessing the situation of non-forest private woodlands: The Turkish case

This paper examines the situation of private woodlands in Turkey, which are referred to as ‘non-forest private woodlands’ (NFPWs). The questions addressed by this study are ‘Why are NFPWs not defined as forest?’, ‘Is the exclusion of NFPWs from forests reasonable?’ and ‘What are the consequences of excluding NFPWs from the forest regime?’. It is found that the criteria used to define a forest in Turkey, and hence to exclude NFPWs from forests, do not have a rational basis. Moreover, the threshold level of area, the most decisive criterion, is far beyond comparable international values and cannot be explained by country peculiarities. Also, NFPWs are more likely to be granted tree cutting approval if they have some type of official cadastre or if they harvest trees for domestic use. Commercial-use NFPWs make tree cuttings in higher quantities than domestic harvesters. NFPWs in general can be perceived as fuelwood harvesters as opposed to industrial wood suppliers. NFPWs with forest or land cadastre tend to harvest at higher levels compared to those without a cadastral survey. In the 8-year period 1993 and 2000, approximately 2.5 M m³ of wood was harvested on NFPWs across Turkey. The annual wood production on NFPWs throughout the country decreased drastically during that period, from about 700,000 m³ down to about 150,000 m³. This may be an alarming sign for environmental and socio-economic sustainability involving these lands. Forest management of these lands can be improved if the forestry administration authority implements planned environment-related regulative criteria as well as sound channels of communication, designed to lead the landowners towards best ‘forest’ management practices and hence to guarantee the sustainability of the communities and the natural resource base of the country.