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31.
竹材利用标准及其国际标准化的需要   总被引:6,自引:0,他引:6  
文章阐明了制定竹材利用标准的意义、原则和思路,分析了我国竹材利用标准的现状,并对标准所涉及的内容进行了描述。通过与印度竹材物理力学性质标准的对比,和试验验证加载速度对竹材力学性质测试结果的影响,指出了我国竹材利用标准的不足及竹材利用标准的国际标准化的需要。  相似文献   
32.
Abstract

Foliar analysis is an effective method to diagnose the nutritional status of plants. However, the mineral concentration in foliar tissue has traditionally been evaluated by assessing the activity of each element, without considering the interactions between them. To address this, dual interactions were calculated using the Diagnosis and Recommendation Integrated System (DRIS) to identify which crop nutrients are most influential in nutrient imbalances and which are the most limiting nutrients for the nutritional status of banana crops in Ecuador. To achieve this, a regional survey of the nutritional status and its productivity levels was conducted for 188 different sites during the crop season in 2017–2018, involving banana cultivars ‘Vallery’ and ‘Williams’, from the Cavendish subgroup. The DRIS calculation method was combined with Beaufils and Jones functions. From the initial 188 foliar samples, 83 samples (representing 44% of the population) were considered to represent the high-yield reference population, with yields of 38–60 t ha?1. The DRIS method defined the mean nutritional balance index, which was not found to be statistically correlated (p?>?0.05) with productivity, revealing that there was no significant association with the nutritional status of the plants. Specific DRIS norms were obtained and indicated that deficiencies in K, N, Ca, and Fe, and excesses in Mn, B, Cl, Zn, S, Cu, and Mg were the most limiting nutrients for banana cultivars in the south of Ecuador.  相似文献   
33.
随着信息技术的发展,电子政务建设也在快速发展。本文根据我国电子政务和档案信息化建设的现状及电子政务环境下的档案信息特点,描述了档案信息管理的各种模式,并对档案信息管理的人才要求、网络建设标准、信息安全等问题提出了自已的见解。  相似文献   
34.
The analysis distinguishes two types of standards for defining organic produce; process standards and product standards. Process standards define organic products by the method and means of production. Product standards define organic by the physical quality of the end product. The National Organic Program (NOP) uses process standards as the basis for defining organic. However, the situation is complicated by agricultural production practices, which sometimes result in the migration of NOP prohibited substances from conventional to organic fields. When this interaction alters the value of the product or the costs of production, a production externality is said to exist. Defining organic using process, rather than product standards, influences the burden and character of production externalities. The NOPs emphasis on process standards reduces the likelihood that production externalities will emerge.B. James Deaton is an Assistant Professor in the Department of Business and Agricultural Economics, University of Guelph, Canada. His research examines environmental and natural resource issues. He is particularly interested in the manner in which laws, rules, and standards influence environmental quality, natural resource use, and economic development. Additional research examines the relationship between different forms of private property and economic development, public support for various criteria used to preserve farmland, and the social construction of production externalities in agriculture. Prior to his PhD training, he worked on economic development projects in Lesotho (Southern Africa) and the Appalachian region of eastern Kentucky.John P. Hoehn is a Professor of Environmental and Natural Resource Economics in the Department of Agricultural Economics, Michigan State University. His teaching and research activities address environmental and natural resource policies, benefit-cost analysis of environmental improvements, methods for valuing non-market goods, improved institutions for protecting, managing, and using environmental resources, and the economics of ecological resources. He teaches core courses in the departmental and university-wide graduate programs in environmental and resource economics.  相似文献   
35.
稻粒黑粉病病穗率与病粒率的关系及其分级标准研究   总被引:1,自引:0,他引:1  
利用田间调查的数据,分析了稻粒黑粉病病穗率与病粒率的关系和发生程度的分级标准。结果表明,病穗率与病粒率的关系以指数函数拟合较好;在病穗率小于80%左右时可以用直线方程拟合。病害发生程度可分为5级。  相似文献   
36.
选择类似条件的长白、大约、长大杂、四元杂断奶仔猪各20头,均等分成两组,分别喂给按美国饲养标准和中国饲养标准配合的日粮,对试验结果进行了最小二乘分析,结果表明,品种组合及营养水平对日增重均有极显著影响,品种组合对后腿比例、瘦肉率、四腿瘦肉率、皮率有显著或极显著影响,对其它性状无显著影响;营养水平除对屠宰率有显著影响外,对其它胴体性状无显著影响,品种组合与营养水平间互作仅在胴体直长、眼肌面积、四腿瘦肉率等少数性状上存在显著影响,采用美国饲养标准饲喂瘦肉型外来品种及其杂种具有饲养成本低,周转快的优点。  相似文献   
37.
Since the turn of the lastcentury, Michigan farmers, elevators, and stategovernment have used production and processstandards to shape the dry bean industry totheir interests and set a worldwide standardfor quality dry beans. Over the last 20 years,however, multinational agro/food firms haveintroduced their market criteria into standardssetting, and recent changes in Michigan beanstandards largely accommodate the interests ofthese firms. A review of the changes in thesestandards over time allows us to explore howconcepts of accountability and control improveour understanding of changes in the structureand operation of food production and marketing.What is the measure of state governmentaccountability to corporate capital and to thestate's bean farmers? In what ways can farmersuse standards to re-assert their priorities andgain a greater measure of influence overmarketing? What challenges do changing qualitystandards pose for public research as well asfor the institutions representing Michiganfarmers and elevators?  相似文献   
38.
中国农村厕所改造及粪污处理标准体系研究   总被引:1,自引:3,他引:1  
农村无害化卫生厕所改造可以有效地减少农村地区粪-口传播疾病的发病率,保障人民群众身体健康和生活品质。2018年以来,农业农村部会同有关部门积极行动,大力推进农村厕所革命,取得了积极成效。然而,一些地方农村厕所"建不好、用不好、不好用"等情况仍有发生,究其根源,农村厕所改造及粪污处理标准规范缺失是重要原因。农村厕所改造及粪污处理标准体系是科学指导农村改厕和粪污资源化利用、规范行业进步和产业发展的重要手段。该研究从基础、通用、专用标准3个层次,系统梳理了中国农村厕所改造及粪污处理现行国家和行业标准,分析了存在的问题,明确了标准体系构建原则和目标,研究构建了标准体系结构和框架,提出了标准体系重点内容和制修订建议,以期为推动中国农村厕所革命提供支撑。  相似文献   
39.
试验表明:不同挖穴规格的幼林生长达到概率保证为95%的统计学上显著与极显著差异水平,以40cm×30cm×25cm的穴规格为最好。种源差异及主副处理的交互作用由于试验林尚小,未达到统计学上的显著差异水平。  相似文献   
40.
白菜对病毒病霜霉病黑斑病的三抗性鉴定与筛选标准   总被引:5,自引:0,他引:5  
白菜对病毒病、霜霉病和黑斑病菌期人工拉种和田间自然诱发相结合的三抗性鉴定与筛选方法标准包括品种试材安排,接种体准备,接种苗龄,接种顺序,病原适比浓度,鉴定怀筛选环境条件,病害的诱地措施和管理,调查方法及病情分级标准,抗病与感病指标,筛选技术和规程等。  相似文献   
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