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苹果黑点病是果树生产中主要的果实病害之一。近几年来由于套袋技术大面积使用,导致苹果黑点病的发生日趋严重,不论是套纸袋还是套膜袋的苹果都会发生黑点病,不套袋的发病较少。被黑点病侵染的果实不会腐烂,但果皮美观度受到影响,苹果商品价值下降,果农的经济收入减少。 相似文献
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2012年,套袋苹果黑点病在山西省运城市套袋果园严重发生,主要是因该病发生的关键时期(即苹果花期、套袋前的幼果期)和7月初降雨较多、田间湿度大而造成的。通过合理施肥、修剪,选用透气性好的膜袋、纸袋,以及剪大透气孔、抓住关键时期用药等综合防治措施,可有效控制套袋苹果黑点病的发生。 相似文献
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苹果黑点病是果树生产中主要的果实病害之一。近几年来由于套袋技术大面积使用,导致苹果黑点病的发生日趋严重,不论是套纸袋还是套膜袋的苹果都会发生黑点病,不套袋的发病较少。被黑点病侵染的果实不会腐烂,但果皮美观度受到影响,苹果商品价值下降,果农的经济收入减少。1.症状初发病时,围绕皮孔,苹果萼洼周围出现一个个如针尖大小的黑点,而后逐渐扩大至如芝麻或绿豆大,但黑点或黑斑只在果皮表面出现,并不深及果肉,无苦味,也不会引起果肉溃烂,在生长后期和贮藏期也不扩大蔓延。2.发生原因 相似文献
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苹果苗木栽植机的设计与试验研究 总被引:1,自引:0,他引:1
针对新型矮砧密植苹果建园劳动强度大及机械化程度较低的问题,应用AIP三维设计软件,设计开发了连续开沟式苹果苗木栽植机。该机采用芯铧式开沟器,为便于维护和转运机架设计成3级连接机构。该机设计开沟深度为30~35cm,开沟宽度为25cm,集苗箱容量为健壮苹果树苗500棵,正常工作速度为0.8~1.2m/s。田间试验结果表明:该栽植机工作性能良好,所栽苗木倒伏率为0.67%,机械伤苗率为0.44%;机具开沟稳定,栽植深度合格率为98.88%,苗木栽植合格率达98.22%;人工充苗作业,株距变异系数20%。该机结构设计合理,栽植作业质量能够满足建园农艺要求,为我国矮砧密植栽培模式下的苹果园建设提供了技术支持。 相似文献
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套袋对苹果果实品质的影响 总被引:1,自引:0,他引:1
套袋是目前苹果栽培上采用的主要技术措施之一。通过比较不同品种苹果套袋与不套袋果实的质量、高度、周长、体积情况,探讨套袋栽培对苹果果实品质的影响,以期为苹果优质高产栽培提供理论依据。 相似文献
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感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
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《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
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从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性,认为在缺水不可避免的情况下,对供水进行优化调度可以减小缺水带来的损失,产生较好的减灾效益,特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性,提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献
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The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献