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保护性耕作适应性评价与模式选择方法研究 总被引:2,自引:0,他引:2
构建了保护性耕作适应性评价指标体系,利用该指标体系,可以快速评价免耕、浅松、深松、平作、垄作、碎秆覆盖、整秆(立秆)覆盖、整秆(倒秆)覆盖、留茬覆盖等关键技术的适应性等级与得分,根据适应性状况,区别独立方案和互斥方案两种不同条件,确定适合的保护性耕作模式. 相似文献
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保护性耕作可以减少土壤风蚀与水蚀,提高作物产量,是发展旱作农业的重要措施。推广保护性耕作必须结合不同地域的气候特点及种植制度,形成具有区域特色的保护性耕作技术体系。垄作免耕技术对东北地区发展保护性耕作具有重要意义。为此,列举了几种垄作免耕技术模式,对其优缺点进行了分析,比较了几种垄作免耕播种机的破茬原理,指出了机具的研究重点应放在开发动土量少和功耗小的破茬部件上,以提高免耕播种机的通过性和作业质量。 相似文献
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为探索适合凤城地区的玉米保护性耕作模式,在抓好示范区建设的基础上,以传统耕作技术模式为对照,进行保护性耕作应用效果试验。试验结果表明:保护性耕作可明显提高耕地土壤的含水量和微生物活性,具有增肥地力和增加玉米产量的作用;高留茬模式是凤城地区的主导技术模式;而碎秆覆盖模式适于在风力较小、秸秆资源丰富地区施用。 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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