伊犁新垦区土壤养分特征与土地开垦的方向探讨   总被引：3，自引：2，他引：1  

石瑞香  杨小唤  王立新 《资源科学》2009,31(12):2016-2023

研究伊犁新垦区土壤养分的空间分布特征及其变化规律,对于合理开发利用土壤资源、优化施肥、建设稳产高产农田等具有重要意义。本文基于实测土壤剖面数据,运用数理统计、地统计学和GIS空间分析方法,研究了伊犁新垦区土壤最上部两层养分的统计特征、空间分布和空间变异,并进行了克里格插值,得到了区域养分的分布图;在此基础上探讨了研究区土地开垦和利用中需注意的问题。研究结果表明：①研究区表土层和第二层的土层厚度平均为10.49cm和19.58cm。表土层和第二层的有机质含量平均为13.72g/kg和10.08g/kg。表土层和第二层的有效氮含量平均为42.54mg/kg和33.98mg/kg,表土层和第二层的有效磷含量平均为12.22mg/kg和4.22mg/kg,表土层和第二层的速效钾含量平均为433.54mg/kg和326.40mg/kg。大部分土壤呈碱性,第二层土壤的碱性比表土层更强;②土壤最上部两层的有机质含量和有效氮含量均呈显著的正相关。土壤有效磷含量和土层厚度呈显著的负相关;③土壤最上部两层的有机质和有效氮的空间变异较大,其次是速效钾、有效磷和土层厚度,PH值的空间变异最小;④土壤最上部两层的有机质、有效磷、速效钾和PH值的空间自相关范围分别是116km、147km、42km和147km。表土层、第二层有效氮的空间自相关范围分别是65km和7km。表土层、第二层的土层厚度的空间自相关范围分别是17km和147km;⑤研究区被开垦时,应适当使用氮肥和磷肥,不必使用钾肥。  相似文献   

农田土壤有机质空间变异的尺度效应     

张法升  刘作新  张颖  苗永刚  曲威  亢振军 《中国科学院大学学报》2009,26(3):350-356

采用10m×10m高密度网格设计,在面积为10.24hm²的农田内取土壤样本1024个,测定土壤有机质(SOM)含量,通过"再采样"方法,研究改变取样幅度和取样间距对表征土壤有机质变异特征的变异系数和半方差函数参数的影响,分析获得土壤有机质空间变异特征的尺度效应.研究结果表明,10.24hm²取样区内,土壤有机质空间分布表现为弱变异性,CV≤3.43%,但整体含量偏低,SOM≤1.04%;随着采样幅度增加,土壤有机质变异性不同程度增加,变异相关范围和结构性变异比例也不断增大;当采样间距增大时,土壤有机质变异性呈无规律变化,但变异相关范围显著增大,而结构性变异比例呈下降趋势.  相似文献   

语言三大特性视角下的翻译     

王皓 《五邑大学学报(社会科学版)》2006,8(4):89-92

作为语用顺应论的重要范畴,语言的三大特性--变异性、商讨性和顺应性,使语言使用者在语言使用过程中能作出恰当的选择,从而更好地阐释各种翻译现象,为研究翻译理论和实践提供了新的视角.  相似文献   

爱米丽·迪金森，其人其诗的哲学符号学解读     

朱梅 《河北师范大学学报(哲学社会科学版)》2007,30(6):81-88

美国符号学之父皮尔斯在19世纪中叶以后提出革命性的哲学观和方法论.他的思想改变了西方传统的认知方法.同一时期,爱米丽·迪金森也创作出大量谜一般的诗作,它们表现了迪金森体验与认知世界的独特方式.这种方式与皮尔斯的哲学符号学不谋而合.  相似文献   

The Influence of Experimental Design on the Detection of Performance Differences     

B. T. Bates  C. R. James  J. R. Harry  J. D. Eggleston 《Measurement in physical education and exercise science》2016,20(4):200-207

We demonstrate the effect of sample and trial size on statistical outcomes for single-subject analyses (SSA) and group analyses (GA) for a frequently studied performance activity and common intervention. Fifty strides of walking data collected in two blocks of 25 trials for two shoe conditions were analyzed for samples of five, eight, 10, and 12 subjects and five, 10, 25, and 50 trials. SSA revealed a greater number of differences (p < .05) than GA for all sample and trial sizes. Increasing sample size resulted in consistent increases in the number of differences for GA; differences for SSA were independent of sample size. Increasing trial size from five to 50 resulted in increased differences for SSA; GA were independent of trial size. Detecting significant differences in group designs is more dependent on the number of subjects, while SSA are more dependent on the number of trials.  相似文献   

Segment coupling and coordination variability analyses of the roundhouse kick in taekwondo relative to the initial stance position     

Isaac Estevan  Julia Freedman Silvernail  Daniel Jandacka  Coral Falco 《Journal of sports sciences》2016,34(18):1766-1773

The initial stance position (ISP) has been observed as a factor affecting the execution technique during taekwondo kicks. In the present study, authors aimed to analyse a roundhouse kick to the chest by measuring movement coordination and the variability of coordination and comparing this across the different ISP (0°, 45° and 90°). Eight experienced taekwondo athletes performed consecutive kicking trials in random order from every of the three relative positions. The execution was divided into three phases (stance, first swing and second swing phase). A motion capture system was used to measure athletes’ angular displacement of pelvis and thigh. A modified vector coding technique was used to quantify the coordination of the segments which contributed to the overall movement. The variability of this coordination (CV) for each ISP was also calculated. Comparative analysis showed that during the stance phase in the transverse plane, athletes coordinated movement of the trunk and thigh with a higher frequency of in-phase and lower frequency of exclusive thigh rotation in the 0° stance than the 90° stance position (P < 0.05). CV was also influenced by the different ISP. During the first swing and the majority of the second swing phase, predominant in-phase coordination of the pelvis and thigh was observed. Including exercises that require in-phase movement could not only help athletes to acquire coordination stability but also efficiency. The existence of a constraint such as ISP implies an increase of the variability when the athletes have to kick from ISP they are not used to adopt (i.e., 0° and 90° ISP) as an evidence of adaptability in the athletes’ execution technique.  相似文献   

用于心率变异信号分析的动力噪声干扰混沌系统建模(英文)     

何振亚  裴文江  尉承建  杨绿溪  S.S.Hull  张隐磐 《东南大学学报》1999,(2)

心脏动力系统可能是其内在动力学和外部环境影响的混合体，因此从心率变异信号中确定混沌现象非常困难．本文提出一种优化方法，获得一组由某种动力系统产生的时间序列，并使该序列与原始信号尽可能接近．对动力噪声干扰混沌模型进行了检验后，应用于心率变异信号分析时发现了正的最大Ｌｙａｐｕｎｏｖ 指数  相似文献   

基于 ArcGIS 地统计分析模块的土壤全磷空间变异与评价--以长沙市为例     

谭陈恬  陈钜辉  陈俊  沈威 《衡阳师范学院学报》2015,(3)

以长沙市为例,采用2013年野外采样室内实验所得数据,运用 ArcGIS 地统计分析模块,利用克里金插值分析其土壤全磷空间分布规律,对长沙市农田利用与管理具有积极意义.结果表明：(1)土壤全磷最优插值模型为 Tetrasphercial 模型,其 C0/(C0＋C)值为4.23％,表现出强烈的空间相关性;(2)在空间上,土壤全磷大致是由东向西逐渐降低;(3)土壤全磷分布在2~5级,且以2级和3级为主.  相似文献   

Why Singapore Trumps Iceland     

Aihwa Ong 《Journal of Cultural Economy》2015,8(3):325-341

The article explores how a National Institute of Health policy of racialization-as-inclusion in research informs the building of Asian DNA databases at Biopolis, an emerging biomedical hub in Singapore. Citing variability in DNA and populations in the Asian region, Singaporean biostatisticians challenge DeCode Genetics of Iceland as an exemplary model of genomic research. They claim that genetic traits among populations in Asia that are relatively new to medical genomics – and being gathered ‘in the wild’ – gain value from being calculated and databased. The infrastructure deploys the ethnic heuristic in different registers. First, the network of ethnicity becomes a supple membrane coextensive with the network of genetic data points. Second, ethnicity is rendered an immutable mobile that circulates databases beyond tiny Singapore, making the infrastructure at once situated, flexible, and expansive. Third, the ethnic signifier carries affective value that enhances a sense of what is at stake in the building, mobilization and implications of such Asian databases. In short, the origami-like folding together of multiple, flowable, and perfomative data points shapes a unilateral topological space of biomedical ‘Asia.’  相似文献   

“人才结构”理论与高职院校人才培养规格     

张静 《科教文汇》2012,(28):174-175

本文首先提出传统的人才结构理论．并就人才结构理论的语源、特点以及该理论与政法类高职院校的人才培养规格的契合之处谈了自己的看法。  相似文献