共查询到20条相似文献,搜索用时 203 毫秒
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木棉(Gossampinus malabarica)又名攀枝花、红棉、英雄树、烽火树,属木棉科木棉属落叶高大乔木.木棉广泛分布在我国四川、云南、贵州、广西、广东,生长在江河沿岸、山地阳坡及村边道路旁,喜光、耐高温,对土壤要求不苛刻.在四川攀枝花地区木棉树于1月-2月份开花,先花后叶,花色艳丽,有红色、金黄、淡黄色等颜色,树形高大伟岸,是优良的园林绿化树种.木棉树现是攀枝花市市花和广州市市树,在园林绿化中常作行道树、庭荫树、景园树、盆景树等.木棉经嫁接后2 a-3 a开花,嫁接苗可作盆景矮化栽培,观赏价值高.本文介绍了木棉的嫁接育苗技术. 相似文献
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One compound approach combining factor-analytic model with AMMI and GGE biplot to improve multi-environment trials analysis 总被引:1,自引:0,他引:1
To improve multi-environmental trial(MET)analysis,a compound method—which combines factor analytic(FA)model with additive main effect and multiplicative interaction(AMMI)and genotype main effect plus genotype-by-environment interaction(GGE)biplot—was conducted in this study.The diameter at breast height of 36 open-pollinated(OP)families of Pinus taeda at six sites in South China was used as a raw dataset.The best linear unbiased prediction(BLUP)data of all individual trees in each site was obtained by fitting the spatial effects with the FA method from raw data.The raw data and BLUP data were analyzed and compared by using the AMMI and GGE biplot.BLUP results showed that the six sites were heterogeneous and spatial variation could be effectively fitted by spatial analysis with the FA method.AMMI analysis identified that two datasets had highly significant effects on the site,family,and their interactions,while BLUP data had a smaller residual error,but higher variation explaining ability and more credible stability than raw data.GGE biplot results revealed that raw data and BLUP data had different results in mega-environment delineation,test-environment evaluation,and genotype evaluation.In addition,BLUP data results were more reasonable due to the stronger analytical ability of the first two principal components.Our study suggests that the compound method combing the FA method with the AMMI and GGE biplot could improve the analysis result of MET data in Pinus teada as it was more reliable than direct AMMI and GGE biplot analysis on raw data. 相似文献
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Natural spruce-fir mixed stand is one of the main forest types in the world,and also has huge ecological,economic and social benefits.According to the structural characteristics and succession laws of natural spruce-fir forest,it is urgent and significant to develop scientific management measures for natural spruce-fir mixed stand in line with local conditions.The article outlined the characteristics of the distribution and structure, regeneration and succession laws of natural spruce-fir forest,and analyzed the current situation and existing problems of natural spruce-fir forest management.The following recommendations were eventually made:1) In no cutting area,all logging activities should be banned.In a restricted cutting area,the cutting intensity should be generally controlled within 15%of the stock volume before cutting.On the commodity forest management area, the appropriate cutting intensity should be determined according to the volume per hectare,determine and classification management should be implemented in accordance with the characteristics of forest,to ensure the scientific selective cutting.2) Closure for afforestation,planting and repair planting should be adopted on vegetation-intensive land,sparse shrubs covered land and harvesting slash,in order to accelerate natural regeneration.3) The in situ conservation should be conducted in nature reserves and scientific experiment stations of rare and endangered species,such as Abies chensiensis,Picea neoveitchii,Abies vuanbaoshanensis,to reduce human destruction.4) It is supposed to collect seeds in time,establish nursery,actively establish forest, expand artificial population and promote natural regeneration. 相似文献
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《技术与市场》2007,(1):23
当前现代化的航天、航空、汽车、机械、电子、民用建筑、化工等行业迫切要求具备很高的力学性能及耐热、耐磨、耐化学性能的材料.因此高分子材料发展的一个重要方向就是通过对现有聚合物进行物理和化学改性,使其进一步高性能化、结构化、工程化.北京化工大学研制的聚氯乙烯合金是通过挤出机的力学、化学作用及接枝、复合技术使聚氯乙烯塑料工程化,成为物理性能可与ABS相比拟的新材料.聚氯乙烯合金具有高流动性、高韧性,完全可以代替ABS注塑计算机、电视机、冰箱、照相机、仪表等外壳.聚氯乙烯合金还具有良好的耐寒性,可制作各种规格的异型材,包括门窗、上水管道等.产品市场前景好,具有很强的竞争力,有很好的经济效益和社会效益. 相似文献
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According to the unification principle of system structure and system function of the Water Resource Conservation Forests,seven factors were selected from stand spatial structure,trees structure and healthy of woods,the multifunction management optimization model target was confirmed by using nonlinearity multi-objective programming approach, and the target function-stand spatial structure homogeneity index was defined to establish spatial optimization models with restraining conditions set up in diversity of stand structure and spatial structure.The spatial structure of available typical stand in the wet land area in southern Donting Lake was optimized by means of selective cutting and reinforcement planting.The results showed that the spatial structure was improved obviously and trees diversity and stand health were not weakened.It’s suggested that the established optimization model can effectively guide multifunction management,stand structure optimization and the steadiness of ecological ecosystem and it is convenient and operable in practice,and it’s very important to protect and recover ecosystem of Water Resource Conservation Forests. 相似文献
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This paper proposes an automatic method of pore combination recognition,which is an important feature to hardwood recognition.After extracting edge from wood microscopic cross-section, based on area histogram of the similar circle regions,the method classifies all regions into two classes with maximum between-class variance,so as to distinguish the pore from other textures,which are similar in shapes but different in sizes.Meanwhile, second objective function about average area of closed regions is used to improve the pore segmentation performance.At last,the method uses adjacency degree of pore set to judge pore combination.The experiments demonstrate that the task of pore segmentation can be completed successfully for all kinds of pore distribution and combination,and also the correct combinations of pores are given. 相似文献
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分析了玉林花卉产业的发展优势、发展现状及生产模式,针对玉林市花卉产业存在的问题,提出了加强政府调控管理、优化生产布局、采用科技手段提高产品竞争力、培养出玉林市的品牌鲜花、引进先进技术和名贵花卉等玉林花卉产业发展对策,以推动玉林现代花卉产业沿着优质、高效的标准化生产道路快速发展。 相似文献
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2015-2018年,在榆林市沿黄生态经济带的吴堡县黄河滩地进行冬枣(Ziziphus jujube cv.dongzao)引种和栽植技术试验,结果为冬枣在当地可安全越冬越夏,生长正常,对土肥水条件要求较高,生长发育期约190~210d,3月下旬前后开始萌动,6月中旬开始结果,7月中下旬果实快速膨大,10月上中旬果实成熟。定植或降树塑形嫁接当年见果,第3年进入丰产期,平均株产10.6kg,平均单果质量可达13 g;栽植应选择地势开阔、光照、土壤等条件较好的地段,采用直接定植或降树塑形嫁接冬枣的方法建园,同时加强土、肥、水管理特别是水肥的有效调控,及时防治病虫害并采收成熟果实。 相似文献
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将数据挖掘技术引入红树林虫害成因分析中,利用广西山口国家红树林生态自然保护区2004—2015年广州小斑螟发生面积数据,分别选取1月和4月平均气温、降水量4个气候因子,采用C 4.5算法在WEKA平台建立决策树模型,预测2016、2017年广州小斑螟发生面积,并检验实际发生情况。结果表明,对广州小斑螟发生影响力由大到小依次为1月降水量,1月平均气温,4月平均气温,4月降水量;该模型分类正确率较高,预测2016、2017年广州小斑螟发生情况与实际情况总体一致。 相似文献
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提高榆林沙区飞播造林治沙成效的研究 总被引:2,自引:0,他引:2
飞播治沙造林种草作为治理榆林沙区的一项主要技术得到了大面积的推广应用,并已取得了明显成效。本文根据近年来榆林沙区飞播治沙造林情况,就现阶段飞播治沙造林中的几个关键技术进行了初步研究,对提高榆林沙区的飞播成效、加快该地区沙地治理速度具有一定的意义。 相似文献
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本文通过实地调查,分析了榆林沙棘资源利用现状及在产业化开发中存在的问题。研究认为,榆林沙棘资源丰富,是沙棘适生区。但品种单一,栽植技术落后、规模化种植程度低、功能产品开发基础薄弱等制约了沙棘资源利用。以政府为主导,市场为导向,科技创新,规模发展的产业化发展措施是实现沙棘产业健康、稳定和可持续发展之路。 相似文献
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榆林市地理位置优越,蜜粉源植物资源丰富,这些蜜粉源植物不仅是发展养蜂业非常有利的条件,而且提供给人们粮食、水果、牧草等。分析了榆林市境内主要蜜粉源植物的资源现状,并就养蜂业的可持续发展问题作了初步探讨。 相似文献