优化试验中常见的统计学错误     

刘宁  梁媛媛  程新 《安徽农业科学》2009,37(22)

以科技文献中常见的优化试验为例,介绍了一些常见的统计学错误,并提出了相应的解决对策。  相似文献   

莲藕切片机推料装置的设计   总被引：3，自引：0，他引：3  

韦恩铸  胡建平 《农机化研究》2008,(11)

莲藕切片机在切片过程中易发生粘刀,从而影响其切片质量.针对一种新型往复式莲藕切片机,设计了一种随动的藕片推料装置.同时,分析了推料过程中,藕片的受力状况,并利用万能试验机测定了藕片与刀片之间的垂直黏附力与水平黏附阻力,得出了藕片的黏附特性,在此基础上得出了推藕板顺利推出黏附藕片的力学条件.通过新型莲藕切片机切片推料试验,得出了在不同工作转速下的推料性能.  相似文献   

Spatial Variation in Soil Organic Matter,Available Phosphorus,and Potassium under Semi-arid Conditions: Research Station Management Implications     

《Communications in Soil Science and Plant Analysis》2012,43(21):2820-2833

Natural ecosystems are characterized by variability in space and, to a lesser extent, in time. Soil types and properties vary on landscape and field scales. Such variability is either inherent or human-induced and influences crop management. Variability at the plot level impinges on field experimentation. In this study at the main station, Tel Hadya, of the International Center for Agricultural Research in the Dry Areas (ICARDA), we intensively sampled four large field plots and analyzed the samples for soil organic matter (SOM), available Olsen phosphorus (P), and extractable potassium (K). Variability parameters were established for each property, as well as semivariograms. Contour maps for each plot were drawn by kriging. Despite the history of uniform management in each plot, large residual spatial variability was evident for each parameter. Although such variability is generally disregarded by agronomists and crop scientists and is generally believed to be eliminated by an alternate year of uniform cropping (i.e., “homogenization”), the residual persistent variability in these parameters cause variation in crop growth and need to be considered in designing experimental treatments, especially with regard to plot size and orientation. Although P and K variability can be masked by uniform fertilizer application, the effects of SOM persist for several years and thus can influence nutrient availability and soil moisture under such dryland conditions. Systematic soil sampling can help in reducing variability at trial sites, but background variability cannot be eliminated completely in natural bodies such as soils.  相似文献   

名茶机械化在安吉县的试验与推广     

金明高  陈杰  马洪亮 《中国农机化》2003,(2):41-42

本文主要阐述了作者在试验基地的研究试验，确定了适合安吉县名茶加工的机型和加工工艺，并制定计划，大力推广名优茶生产机械化技术，加快安吉县茶业经济的发展。  相似文献   

我国复合地基的理论与试验研究进展     

杨海旭  刘飞  翁丽娅  甘玉叶  岳德金 《森林工程》2006,22(1):52-54

阐述了复合地基的理论研究和试验研究现状．找出了我国发展复合地基技术理论与实践亟待解决的问题及褥垫层加固机理，地基刚度分布对地基反力分布的影响。群桩效应及群桩合理布型等提出了今后需要开展的研究工作。  相似文献   

The “Null Hypothesis” of Precision Agriculture Management     

Whelan  B. M.  McBratney  A. B. 《Precision Agriculture》2000,2(3):265-279

As precision agriculture strives to improve the management of agricultural industries, the importance of scientific validation must not be forgotten. Eventually, the improvement that is imparted by precision agriculture management must be considered in terms of profitability and environmental impact (both short and long term). As one form of precision agriculture, we consider site-specific crop management to be defined as: Matching resource application and agronomic practices with soil and crop requirements as they vary in space and time within a field. While the technological tools associated with precision agriculture may be most obvious, the fundamental concept will stand or fall on the basis of scientific experimentation and assessment. Crucial then to scientifically validating the concept of site-specific crop management is the proposal and testing of the null hypothesis of precision agriculture, i.e. Given the large temporal variation evident in crop yield relative to the scale of a single field, then the optimal risk aversion strategy is uniform management. The spatial and temporal variability of important crop and soil parameters is considered and their quantification for a crop field is shown to be important to subsequent experimentation and agronomic management. The philosophy of precision agriculture is explored and experimental designs for Precision agriculture are presented that can be employed in attempts to refute the proposed null hypothesis.  相似文献   

GPS在南方林区的应用试验     

肖红生  纪献华  赵宇光  罗富和  陈义刚 《华南农业大学学报》2000,21(2):5-7

应用Ｍａｇｅｌｌａｎ Ｐｒｏｍａｒｘ Ｘ－ＣＭ ＧＰＳ接收机在广东省新丰县小镇镇林区进行野外样地定位等试验,结果表明,林冠郁闭度、天线类型、天线高度对卫星信号的接收均有一定的影响;ＧＰＳ在杉木林中基本能定位;ＧＰＳ与ＴＭ卫星影象套合误差小于一上象元;差分ＧＰＳ定位技术在南方山区林业调查应用是可行的。  相似文献   

垂向异重流式分离鳃在动水中的集成试验研究   总被引：2，自引：2，他引：0  

张翔  邱秀云  李琳  赵涛  李慧 《新疆农业大学学报》2010,33(4):359-362

通过集成垂向异重流式混合流体水沙分离鳃的动水沉降试验,分析了沉淀时间、进流速度与溢流浓度的关系,并对溢流液体进行了颗分试验。试验表明,通过控制进流速度,可以调节溢流浓度的大小。动水沉降试验在一定程度上可以达到泥沙在静水沉降时的效果,对加速水沙分离的效果明显。  相似文献   

Agroforestry experimentation: Separating the wood from the trees?   总被引：1，自引：1，他引：0  

Peter A. Huxley 《Agroforestry Systems》1987,5(3):251-275

ICRAF has evolved and evaluated experimental approaches to agroforestry problems which will help resercchers reach practical conclusions most cost-effectively in the shortest possible time, and with only limited resources. This has meant looking into the experimental phases needed, developing the conceptual background to research problems which involve the complex spatial/temporal features of agroforestry systems, suggesting and initiating simplified field experimental designs and/or assessment methodologies, and establishing source and reference design materials about agroforestry research for distribution.These four sets of activities are outlined and briefly discussed in relation to some of the key research issues which have emerged.Suitable methods for many areas of experimental agroforestry are rapidly being defined, although some of the more complex issues (e.g. multistrata systems, on-farm research with multipurpose trees and tree/crop mixtures) still need a focused attempt to develop appropriate research methodologies.Head, Research Development Division, ICRAF  相似文献   

7个耐寒桉树的无性系区域试验   总被引：1，自引：3，他引：1  

李宝福 《中南林业科技大学学报(自然科学版)》2007,27(3):14-19

在福建中亚热带开展7个桉树无性系的区域试验研究.结果表明:巨桉3号速生性、适应性和耐寒性强,生长量高,稳定性较好,可耐-4.0～-4.5℃的低温,DH 201-2、巨桉1号和DH 184-1生长量较高,速生性、适应性和抗逆性较强,稳定性好,可耐-3.5～-4.0℃的低温,这4个无性系适合在福建中亚热带年平均温度19℃以上的不同区域选择应用;柳窿桉9号速生性中等,耐寒性有限,只可耐-2.0～-2.5℃的低温,而赤桉1号和赤桉3号虽耐寒性强,可耐-5℃的低温,但速生性差、产量低,且这3个无性系的变异性大,稳定性差,适应范围窄,作为短周期工业原料林不提倡在该区发展.  相似文献