Estimation of Crown Temperature of Winter Wheat and the Effect on Simulation of Frost Tolerance

Accurate estimation of winter wheat frost kill in cold‐temperate agricultural regions is limited by lack of data on soil temperature at wheat crown depth, which determines winter survival. We compared the ability of four models of differing complexity to predict observed soil temperature at 2 cm depth during two winter seasons (2013‐14 and 2014‐15) at Ultuna, Sweden, and at 1 cm depth at Ilseng and Ås, Norway. Predicted and observed soil temperature at 2 cm depth was then used in FROSTOL model simulations of the frost tolerance of winter wheat at Ultuna. Compared with the observed soil temperature at 2 cm depth, soil temperature was better predicted by detailed models than simpler models for both seasons at Ultuna. The LT50 (temperature at which 50 % of plants die) predictions from FROSTOL model simulations using input from the most detailed soil temperature model agreed better with LT50 FROSTOL outputs from observed soil temperature than what LT50 FROSTOL predictions using temperature from simpler models did. These results highlight the need for simpler temperature prediction tools to be further improved when used to evaluate winter wheat frost kill.     

基于非洲猪瘟病毒标准物质的荧光PCR检测试剂盒初步评价

为探究非洲猪瘟病毒(African swine fever virus,ASFV)标准物质作为试剂盒评价体系的可行性,比较了市场上5种主流品牌ASFV荧光PCR检测试剂盒的检测性能。使用ASFV P72基因核酸标准物质作为模板,根据5种试剂盒说明书分别进行相应的荧光定量PCR检测,结合扩增曲线、Ct值,分析不同试剂盒的敏感性、可重复性以及所需反应时间。结果显示:5种试剂盒的阴性、阳性对照均成立,最低检测限均为5.9×10^-1拷贝/μL;4个厂家的试剂盒线性关系R2>0.98,其中最优的R²=0.994,离散度最小;各试剂盒的实际反应耗时与理论反应耗时均有一定差异(0.20~0.96 h)。结果表明,各生产厂家使用P72基因作为靶基因研制的ASFV荧光PCR检测试剂盒都可以使用ASFV标准物质作为评价体系,来评判试剂盒的检测性能。本试验为各实验室不同样品检测的ASFV荧光PCR检测试剂盒选择提供了一种可用的评价方法。     

Isolation and Identification of BPIV3 Genotype C

To identify the infection agents from Ningxia Hui Autonomous region, where feedlot cattle indicated bovine respiratory disease complex (BRDC), the M gene of the bovine parainfluenza virus type 3 was amplified by RT-PCR.The PCR product was ligated to pMD18-T vector and cloned to E.coli DH5α.The positive clones were sequenced and compared with the reference strains in GenBank by the molecular biology software.Sequence alignment results showed that a BPIV3 strain was isolated from the samples and named NX49, the M gene of NX49 included 1 056 nucleotides.Evolutionary analysis showed that the NX49 belonged to BPIV3 C genotype and shared 99.4% nucleotide identity with that of the SD0835 isolated in Shandong province.The characterization of the NX49 demonstrated that it was sensitive to temperature, acid and organic matter.The presence of Mg²⁺ showed no protection against the treatment at high temperature.The HA test suggested that the NX49 enables to agglutinate the guinea pig RBC at 4 ℃ and the titer was 1∶4.The study isolated a BPIV3 genotype C strain successfully, which facilitate the study of molecular evolution and epidemiology of BPIV3 in China.     

A MATHEMATICAL MODEL OF FUZZY EVALUATION METHOD FOR ENVIRONMENTAL POLLUTION

The problem of fuzzy evaluation of environmental pollution is importantboth in environment science and in environmental protection.Usual evaluationmethods have their own characteristics.This paper puts forward a mathematicalmodel of fuzzy evaluation method in grades by means of systematic analysisfor environmental pollution.At the same time,it assigns weighted values byordering based on paired comparison.     

不同沙棘品种在定西的生长情况对比分析

通过对引进的7个沙棘品种的种子育苗及成苗定植，并对成活率、保存率、生长情况进行了观测，初步分析了引进的各沙棘品种类型在定西的适应性。     

灌区评估指标的选取及灰关联分析

该文探讨了灌区评估指标体系的建立方法,对评估指标的选取与预处理进行了系统分析,并尝试应用灰色系统理论中的灰关联度分析法,对灌区评估指标进行关联分析,从而很方便地进行灌区之间的评估、排队及比较,与传统的强制打分法相比,此法简便易行,无需预先建立评判标准,因此是一种新的评估分析法。     

农业技术经济动态方法的适用性

农业技术经济学研究的根本目的是为了实现农业生产资源的优化配置,提高农业生产效率,发展农业生产,提高农民生活水平,保障社会对农产品的需求。净现值法和内部收益率法是农业技术经济分析中常用的两种动态方法,它们各有其优缺点和适用范围,为此对两方案进行应用上的比较,正确理解方法特点和经济含义,具有重要的实际意义。