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本文根据香蕉各级别冻害的气象指标,统计漳州市各地冬季出现香蕉重冻害、中冻害、轻冻害、微冻害的频率,然后根据出现香蕉重冻害的频率大小,把全市蕉区划分为香蕉微冻害区、轻冻害区、中冻害区、重冻害区和严重冻害区,最后进行分区评述和提出香蕉防冻减灾的途径. 相似文献
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以1981—2010年度商丘市小麦生长季的气象数据为资料,系统地研究了小麦生育期冻害发生规律,深入地分析了形成原因。研究表明:该区小麦冻害10年10遇,重灾年率为10年8遇。与常年相比,冻害的发生频率呈现变化不大,危害程度呈现冻害有所减轻的趋势;时期呈现冻害初冬和早春逐渐减少,越冬和晚霜逐渐增多的态势;空间分布呈现冻害东部重,西部次之,中部轻的特征。从冻害形成原因上来看,该区每年冬初至春末冷暖空气交替频繁,气候多变,低温灾害性天气多;另外,由于耕层浅、播量过大、水肥管理不适等人为因素也会造成小麦易遭受冻害。 相似文献
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调查了福建省大田县梅山乡3年生和1年生邓恩桉遭受2011年初春持续低温后的生长表现（以冻害指数为指标）。结果表明：不同海拔高度邓恩桉的冻害指数差异极显著,随着海拔高度的升高,邓恩桉冻害指数增大;低温对海拔400 m以下的邓恩桉生长影响不明显,对海拔400-750 m的邓恩桉冻害指数影响极大,导致海拔750 m以上的邓恩桉死亡;同一海拔水平上1年生邓恩桉受冻害的危害明显大于3年生,1年生邓恩桉下坡、中坡和上坡的平均冻害指数差异不显著,3年生邓恩桉下坡、中坡和上坡的平均冻害指数依次显著增大;冻害指数与树高、地经均呈显著负相关,说明随着邓恩桉林龄的增加,树高、胸径生长,抗冻害能力明显增强。 相似文献
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根据全球气候变化与大麦春季冷害或冻害发生频率的关系及大麦品种对春季冻害抗性与品种特性、播期、密度、土壤墒情等因素的关系 ,分析了 2 0 0 4年方强农场不同大麦品种的发生春季冻害程度及对产量影响程度。结果表明 :随着暖冬频率的增加 ,大麦遇到春季寒害的可能性增加 ,对一些早熟品种应适当推迟播种期 ,注意协调前期群体与个体生长的协调性 ,增强大麦品种对春季寒害的抗性。大麦品种对春季冻害的抗性受多方面的因素影响 ,冻害发生后不同品种的补偿能力不同 ,不同栽培技术对同一品种的恢复程度存在一定的差异 ,不能单从冻害发生的表面现象来判断某一品种对春季冻害抗性的好差。 相似文献
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集安市位于吉林省的东南部 ,是人参、西洋参主要产区之一 ,种植人参有几百年的历史 ,种植西洋参也有近 30年了 ,还未发生过较严重的冻害。但去年冬季的异常气候 ,造成今年集安市人参、西洋参冻害的大面积发生。就此我们对这次人参、西洋参冻害的基本情况及冻害原因 ,作了具体的调查 ,为广大参农发展参业提供一些技术资料。集安人参研究所于 2 0 0 2年 4月 5日至 4月 2 8日先后 5次对集安市人参、西洋参冻害情况进行了调查 ,现就对冻害的调查和观察结果作一初步报道。1 冻害的基本情况 (分布、数量、损失程度、环境条件 )据调查 ,冻害在全市… 相似文献
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随着经济的发展,社会的进步,天气的影响,茶树冻害的预防补救措施和效益越来越引起人们的重视,经过几年来的实践经验,现将天气实况、冻害类型、冻害预防和补救措施及其效益比较介绍如下。 相似文献
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Textile fibers were obtained from secondary polyethylene terephtalate (PET) and its mixtures with primary PET at initial orientation of 18000–33000 %, rate of additional orientation drawing 3.5–6.5 times and temperature of thermal fixation 363–413 K. The fibers’ tensile strength was found to decrease and elongation at break to increase with the decrease of their linear density under the conditions of fibers formation. For the fibers based on polymer mixtures, the presence of oxidized fragments in the secondary PET limited the compatibility of the two polymers which resulted in deteriorated tensile properties. The linear density (4–16 dtex), tensile strength (30–50 cN/tex) and elongation at break (20–60 %) of the PET fibers obtained were close to these for the industrially produced polymer fibers. The values of the average diameter of the fibers formed and oriented under laboratory conditions allows classifying them between the fine and the coarse textile fibers which makes them suitable for the textile industry. 相似文献
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Gas-exchange characteristics of potato (Solanum tuberosum L.) canopies were determined with crop enclosures under condition of optimal water supply, during soil water depletion, and during recovery from drought-stress. The plants were grown under a rainshelter in large containers with 2-m2 surface area. Control plants received water throughout the growth period. In Expt. 1, transient drought was imposed by interrupting water supply completely for 22 days. During the 33-day period of drought treatment in Expt. 2, the stressed plants received half the amount of water that was given to the control plants (irrigations 2–3 times per week).
During soil water depletion, stomatal conductance of the canopy was reduced earlier and more than photosynthesis. This resulted in a lower internal carbon dioxide concentration in the leaves of stressed plants and a higher ratio between photosynthesis and stomatal conductance. The value of that ratio increased as soil water potential dropped.
Water-use efficiency ( ) increased during drought stress. The cultivar Bintje showed a larger ratio between photosynthesis and stomatal conductance of the canopy and a higher than cv. Saturna, both for optimal water supply and during drought stress.
Photosynthesis and conductance of the canopy started to recover immediately upon rewatering, even when relative values had declined to 20–30% during the preceding stress period. After release from stress, the leaves in the top layer of the canopy had a higher stomatal conductance in treated plants than in control plants. 相似文献
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《Journal of Crop Improvement》2013,27(1):313-324
Summary Arbuscular mycorrhizae were inoculated into phosphorus-deficient soil fertilized with either organic or chemical fertilizer with cucumber (Cucumis sativus L.) as the first crop and lettuce (Lactu-ca sativa L.) as the second crop but without additional fertilization and AM inoculation. AM increased dry matter and fruit yield of cucumber significantly in the unfertilized, organic-fertilized and P-deficient plants compared with the fully chemical-fertilized plants. AM inoculation increased the available phosphorus in plant and soil by around 30% for all treatments except for those chemically-fertilized. The rate of AM infection did not differ significantly among the fertilization treatments, but the infection intensity was higher in unfertilized, organic-fertilized and phosphorus-deficient treatments than chemical-fertilized treatment. The residual effects of AM-inoculated to cucumber were evident for lettuce in all pre-treatments that were unfertilized and un-inoculated for the second cropping. Without P-fertilization, neither crop could grow optimally even when the soil was inoculated with AM, suggesting that AM could not serve as a substitute for phosphorus fertilizer. However, the other beneficial effects of AM on crop growth and yield could not be fulfilled with phosphorus fertilizer. 相似文献
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2017—2018年,在同安镇粮食产能区示范推广水稻病虫害绿色防控与统防统治融合技术模式,取得了显著成效。融合技术示范区比常规区减少用药2~3次,用药量减少37.6%,防治成本降低400元/hm^2;水稻产量增加12.8%,收益增加2 835元/hm^2。 相似文献
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生物质能作物——甘薯开发利用现状及趋势 总被引：13，自引：0，他引：13
甘薯是世界上重要的粮食、饲料、工业原料及新型能源用块根作物，在我国乃至世界再生能源开发中起到重大作用，其分布地域广，适应性强，沙荒地、岗坡地均可种植。生物产量高，而且种植栽培容易。甘薯含淀粉15％～30％，晒干率20％～35％，世界各国以薯干或淀粉为原料生产乙醇有着悠久的历史。随着全球能源的日趋紧张，乙醇作为一种可再生的环保燃料．将快速步入全球成品油市场，在替代汽油供应方面起到越来越大的作用。各国正在推行或制定燃料乙醇计划，并着眼于生物燃料乙醇应用方案，认为甘薯可能是摆脱将来粮食和能源危机的“最后一张王牌”。 相似文献
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为明确春季调控措施对冬小麦生长发育和籽粒产量的影响,以冬小麦品种石新828为材料进行田间试验,4个处理分别为:起身期追全部氮肥(除基肥外,下同)并叶面喷多效唑(N1);起身期追2/3氮肥并喷多效唑+拔节期追1/3氮肥(N2);起身期追1/3氮肥+拔节期追2/3氮肥(N3);拔节期追全部氮肥(N4)。生育期间测定群体和个体生育特性,成熟期调查产量性状。结果表明,N1和N2处理小麦拔节期的总茎数、叶面积指数(LAI)和干物质积累量均显著高于N4和N3处理。孕穗期N4和N3处理小麦的总茎数、LAI和干物质积累量显著高于N1和N2处理。开花到成熟期各处理的总茎数、LAI和干物质积累量差异均不显著。孕穗期前,不同处理的株高差异不显著,孕穗期后,N4处理的株高最高,且显著高于N1处理。各处理基部节间直径和中上部节间长的差异不显著,N4处理基部第一节间长度显著大于其他处理。随追氮时期前移或前期施氮量增多,不孕小穗数减少,结实小穗和穗粒数增加,N1比N4处理不孕小穗数显著减少,结实小穗和穗粒数显著增多。N1处理小麦成熟期的千粒重最高,且显著高于N4处理。N1处理的籽粒产量最高,且显著高于N3和N4处理。起身期追氮配合多效唑调控,可以获得比拔节期追氮更高的穗粒数和千粒重,从而获得更高的产量。 相似文献
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施镁量和施镁方法对烤烟生长发育和烟叶产量的影响 总被引：4，自引：0，他引：4
采用盆栽试验，研究施镁量和施镁方法对烤烟生长发育和烟叶产量的影响，结果表明：适量施用镁肥，可以促进烟草的生长发育、改善其农艺学性状，影响烟株对其它营养元素的吸收与积累，提高烟叶产量，并能使烟叶N，P，K，Ca等营养元素含量更趋协调。随着施镁量的增加，烟叶中镁含量提高10．7％～71．4％，烤烟单株吸镁量、叶片叶绿素含量、干物质产量分别提高17．6％～115．4％，1．9％～23．ooA和6．3％～25．7％，而对烟叶含钾量没有明显影响。在镁比较缺乏的土壤上，镁肥作基肥施比叶面喷施的效果好，基肥施镁结合叶面喷镁的效果最佳；叶面喷镁，肥料用量少、成本低、见效快，是一种有效的镁肥施用方法；提高镁肥用量，施镁的效果更加显著。 相似文献