影响胚胎移植成功率的主要因素

本文针对在胚胎移植过程中可能预见的各种影响胚胎移植技术的实施的因素进行了较为全面的分析,并针对不同影响因素提出了自己独特的见解,以期在生产实践中对胚胎移植技术的应用和推广有所借鉴。     

2.5%菜喜胶悬剂对甘蓝小菜蛾和菜青虫的防效

生物源杀虫剂2.5%菜喜胶悬剂防治甘蓝小菜蛾和菜青虫的田间药效试验结果表明,2.5%菜喜胶悬剂1 000、1 500、2 000、3 000倍液防治甘蓝小菜蛾和菜青虫的速效性好,药后第1 d的防效优于20%氰戊菊酯乳油2 000倍液和20%米满悬浮剂2 000倍液.以1 000倍液防效最好,药后第1天、第3天、第7天对小菜蛾的防效分别达91.42%、94.46%、92.77%,对菜青虫的防效分别达93.18%、96.06%、94.48%.示范结果表明,2.5%菜喜胶悬剂1 000倍液对小菜蛾的防效为89.74%～92.76%,对菜青虫的防效 90.19%～93.47%.从防效、成本等方面综合考虑,大面积示范推广该药剂的适宜剂量为1 000倍液.     

创新工作思路，全面提高农业综合开发水平

城步苗族自治县把农业综合开发作为解决“三农”问题的具体工作来抓，不断转变工作思路，增强开发意识．全面提高了农业综合开发水平，推动了县域经济的平稳较快发展。     

欧洲赤松引种试验初报

树木引种驯化在林业发展中,始终具有较强的魅力。这是由于一个优良的树种,理性地引入一个地区后,所带来的良性变化决定的。欧洲赤松生长快、抗性强、耐干旱瘠薄、耐高寒。我们从80代即开始了国内外松属植物的引种工作,其中欧洲赤松(pinusdensiflorasieb·etzucc)是较为成功的一例。本文实录了20余年赤松引种驯化情况,以供同行们参考。     

辽东冷杉引种研究

辽宁冷杉,其生长快、抗性强、耐干旱瘠薄、耐高寒。经过20余年的试验,该树种在伊春地区引种已获成功。本文从3个方面较详细介绍了辽宁冷杉的引种驯化情况。     

强力推进农业开发，有效实现农企“双赢”

近几年来，祁阳县积极利用农业综合开发惠农助农政策，以实施产业化经营项目为契机．以发展优质稻这一支柱产业为主攻方向，将推进农业产业化与加强农业基础设施建设有机结合起来，走出了一条农业综合开发扶大扶强龙头企业，龙头企业带动支柱产业发展和农民持续增收，最终实现农企互动“双赢”的路子。     

地面青贮应用技术研究

2003年9～10月份在昆明市的四个点开展地面青贮应用技术研究,结果表明:(1)、地面青贮的制成率96.79%;(2)、地面青贮与窖式青贮的DM、CP、EE、Ash、Ca、P、NDF、ADF差异不显著(P>0.05);(3)各试验点间的地面青贮营养成分除Ash差异显著(P<0.05)外,其余成分差异均不显著(P>0.05)。     

新疆黑槌虫草羽束梗孢菌的液体深层发酵控制

为提高液体深层发酵生产新疆黑槌虫草羽束梗孢菌的成功率,从发酵配套装备和发酵过程控制入手,结合生产实际,发酵配套装备中在发酵罐机械密封、管道、空气净化系统、阀门等关键点,发酵过程控制中在灭菌时间、发酵参数控制、接种移种取样控制上提出了预防发酵染菌的方法,杜绝发酵染菌隐患,将黑槌虫草羽束梗孢菌发酵成功率最初不到50%提高到目前的90%以上。     

无棣贝沙堤植物多样性分析

通过对无棣贝沙堤植物多样性的分析发现,样方内共出现物种20余种;同时,贝沙堤向海面和贝壳滩脊、向陆一面分别分布着以芦苇、獐茅、大穗结缕草、二色补血草、砂引草以及以青蒿、蒙古蒿、阿尔泰紫菀为优势种的群落。由于人为影响强度不同,大口河和王子堡地区物种盖度、物种多样性指数存在显著差异,分别处于演替初级和次级阶段。而从贝沙堤向海-滩脊-向陆断面上来看,群落多样性指数不断增加．群落更趋于稳定。     

Estimation of GPS positional accuracy under different forest conditions using signal interruption probability

We proposed a signal interruption probability (SIP) value indicating the frequency of global positioning system (GPS) signal interruption or the fragmentation of GPS data, and used it to estimate the success probability of ambiguity resolution in carrier-phase differential GPS (DGPS) as well as the horizontal precision of code-phase DGPS under different forest conditions. In field tests, a rover was set up at four observation points, each representing a different condition within a forest. At each observation point, static surveying was conducted for four periods of 30 min, and data from the first 1, 5, 15, and 30 min from each observation point were extracted for analysis. The position of each point was calculated by baseline analysis using three types of GPS data, i.e., dual-frequency (L1 and L2), single-frequency (L1), and code-phase DGPS data. The results showed that ambiguity resolution was a key factor in determining the horizontal accuracy of carrier-phase DGPS, and that the success probability of ambiguity resolution differed greatly according to forest conditions, which were well explained not by the index of the canopy opening but by the SIP. Furthermore, estimation of the success probability of ambiguity resolution was made based on the SIP and the observation period using a logistic regression model. The horizontal precision of code-phase DGPS was also estimated based on the SIP and the observation period. In conclusion, the SIP was found to be an effective indicator of GPS positional accuracy under different forest conditions.