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康红梅 《山西农业:致富科技版》2008,14(6)
随着农业产业结构的调整,枣树已成为山西省主要的经济林树种.枣树抗干旱,抗盐碱,耐瘠薄,易繁殖,好管理,结果早,寿命长;枣果营养价值高,药用价值大,经济效益好而深受农民的喜爱,目前山西省枣树栽培面积已达30多万公顷. 相似文献
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枣树是中国第7大果树树种,作为中国的特有树种,在全国各地均有广泛种植.枣树具有适应性强、寿命长、效益好、收效快的特点,成为许多地区优先发展的经济树种.近年来宾川县名优特产黑腰枣发展迅速,截至2007年年底,全县共种植黑腰枣427.2 hm2.挂果184.47 hm2,每公顷产值最高可达15万元. 相似文献
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景泰县枣树桃小食心虫的发生及综合防治 总被引:2,自引:1,他引:1
桃小食心虫(Cayposina niponensis Walsingham)又名桃蛀果蛾,简称桃小,俗称钻心虫、枣蛆,属鳞翅目蛀果蛾科,是枣树的主要害虫.此外,还为害苹果、桃、梨、杏、山楂、李等多种果树.枣树是景泰县桃小食心虫为害最为严重树种之一.景泰县枣树栽培面积达2 633.3 hm2,集中分布在景泰县沿黄灌区,已成为当地的主要经济树种.但枣树病虫害发生普遍,桃小食心虫为害程度呈加重趋势,个别严重的枣园虫害率达80%.笔者通过多年的实践,总结出桃小食心虫在景泰县沿黄灌区的发生规律和防治措施. 相似文献
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枣树是我国古老及特有的经济树种,因其经济、生态和社会效益高,使之成为分布全国、栽培面积较大的经济树种,是山区农民脱贫致富的重要支柱产业。通过酸枣嫁接大枣技术,综合地利用了当地野生酸枣资源,同时进行枣树树体改造、树体管理、肥水管理、病虫害无公害防治、 相似文献
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临汾市是山西省中南部无公害果菜产业经济区,也是国家农业部规划的黄土高原苹果产业优势区域,2005年底,全市水果面积发展135.6万亩,水果总产量68.1万吨,总产量10亿元,农业人口人均果品收入310元。水果业快速发展的同时,还存在着一系列问题,尤其是1993年我国苹果市场出现滞销以来,我市苹果走的是一条在调整中发展,在发展中调整的道路。今后,我市水果业要适应花样增多、数量增大、质量增高的市场需要,继续搞好结构调整,以拳头前品、优质产品占领市场。树种结构调整变传统树种为多样化树种上世纪80年代初期,我市水果栽培树种主要是苹果、梨2大… 相似文献
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近几年来,在农村种植业结构调整中,优质枣树种植面积不断扩大。但枣树是开花多、坐果率低的树种,常因管理技术措施不到位,造成相当多的枣树花多、坐果少,影响了枣农的收益。为提高枣树坐果率和减少落花落果,在花果期要抓好以下8个关键。 相似文献
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本试验以菜豆品种先行者为试材,采用32孔、50孔两种规格穴盘,设置10、15、20、25 d等4个苗龄段,通过研究不同穴盘规格和苗龄对菜豆性状及产量的影响,筛选出适合菜豆育苗的穴盘规格和适宜的苗龄。结果表明:穴盘育苗的营养面积增大,菜豆产量随之增加,25 d苗龄条件下,32孔穴盘的前期产量和总产量均显著高于50孔穴盘;随着苗龄的增长,菜豆的前期产量和总产量呈增加趋势,其中25 d苗龄的产量显著高于其他苗龄。综合上述各项指标,菜豆育苗阶段,10 d苗龄可选用32孔、50孔穴盘,15 d以上秧苗选用32孔穴盘为宜。 相似文献
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氮素作为重要的营养元素,限制着小麦的生长发育和经济产量,筛选和培育耐低氮小麦品种是提高氮素利用率、降低生产成本的有效途径。以118份不同基因型小麦为材料,在低氮(0.1 mmol·L-1)和正常氮(5 mmol·L-1)条件下苗期水培,测定根干重、茎叶干重、根冠比、植株干重、最大根长、初生根数和二级初生根数等相关指标,采用模糊隶属函数法、主成分分析以及聚类分析法综合评价小麦品种的耐低氮性。结果表明,在低氮胁迫下小麦幼苗的根干重、根冠比和初生根数目显著提高,茎叶干重、植株干重和最大根长不同程度的降低,7个苗期性状指标在两个氮水平下均存在显著性差异。主成分分析提取3个主成分,贡献率分别为 43.575%、22.904%和17.873%,累积贡献率达 84.351%。以耐低氮性综合评价D值进行聚类分析,将118份小麦品种划分为强耐低氮型、耐低氮型、中间型、较敏感型和敏感型5类。筛选出3份耐低氮型小麦(齐大195、金丰7183和天民198)和2份强耐低氮型小麦(山农0917和鲁麦8号)。不同小麦品种的耐低氮机制不同,研究结果为小麦耐低氮品种的选育提供理论依据和材料基础。 相似文献
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ICP-OES法同时测定果蔬中铅、砷、镉、铬、铜、锡含量 总被引:2,自引:0,他引:2
果蔬样品经混酸消化后,控制一定的酸度,定容后应用等离子体发射光谱法(ICP-OES)对果蔬中铅、砷、镉、铬、铜、锡六种有害重金属进行测定,研究了分析测定条件,方法简单快速。测定结果表明,五种元素的加标平均回收率在91.0%~107%之间。其RSD均小于3.5%。按该方法进行处理及测定铅、砷、镉、铬、铜、锡,在选择的测定条件下最低检出限分别为0.0006 mg/kg、0.0003 mg/kg、0.00003 mg/kg、0.00005 mg/kg、0.00003 mg/kg、0.0006 mg/kg。 相似文献
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Segregation of form, color, movement, and depth: anatomy, physiology, and perception 总被引:63,自引:0,他引:63
Anatomical and physiological observations in monkeys indicate that the primate visual system consists of several separate and independent subdivisions that analyze different aspects of the same retinal image: cells in cortical visual areas 1 and 2 and higher visual areas are segregated into three interdigitating subdivisions that differ in their selectivity for color, stereopsis, movement, and orientation. The pathways selective for form and color seem to be derived mainly from the parvocellular geniculate subdivisions, the depth- and movement-selective components from the magnocellular. At lower levels, in the retina and in the geniculate, cells in these two subdivisions differ in their color selectivity, contrast sensitivity, temporal properties, and spatial resolution. These major differences in the properties of cells at lower levels in each of the subdivisions led to the prediction that different visual functions, such as color, depth, movement, and form perception, should exhibit corresponding differences. Human perceptual experiments are remarkably consistent with these predictions. Moreover, perceptual experiments can be designed to ask which subdivisions of the system are responsible for particular visual abilities, such as figure/ground discrimination or perception of depth from perspective or relative movement--functions that might be difficult to deduce from single-cell response properties. 相似文献
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Zhang M Fang S Zakhidov AA Lee SB Aliev AE Williams CD Atkinson KR Baughman RH 《Science (New York, N.Y.)》2005,309(5738):1215-1219
Individual carbon nanotubes are like minute bits of string, and many trillions of these invisible strings must be assembled to make useful macroscopic articles. We demonstrated such assembly at rates above 7 meters per minute by cooperatively rotating carbon nanotubes in vertically oriented nanotube arrays (forests) and made 5-centimeter-wide, meter-long transparent sheets. These self-supporting nanotube sheets are initially formed as a highly anisotropic electronically conducting aerogel that can be densified into strong sheets that are as thin as 50 nanometers. The measured gravimetric strength of orthogonally oriented sheet arrays exceeds that of sheets of high-strength steel. These nanotube sheets have been used in laboratory demonstrations for the microwave bonding of plastics and for making transparent, highly elastomeric electrodes; planar sources of polarized broad-band radiation; conducting appliqués; and flexible organic light-emitting diodes. 相似文献
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