小型葡萄覆土机的研制和试验研究     

李建萌  冯帆  马世俊  赵凤芹 《农机化研究》2011,(10)

针对葡萄覆土机研发过程中存在的问题,在对葡萄覆土机的基本结构和工作原理进行了深入分析的基础上,对系统的关键部件做了详细设计,完成了整机建模和样机制作。为了验证设计的合理性和实用性,对其进行了性能试验研究。结果表明,样机各项性能指标均能达到设计要求,具有动力匹配合理和生产效率高等特点,为葡萄覆土机的进一步研制及优化设计提供了理论依据。  相似文献   

带翼深松铲的试验研究   总被引：3，自引：0，他引：3  

甄文斌  杨丹彤  黄世醒 《农机化研究》2011,33(8)

通过深松铲在南方砂壤土的深松试验,研究带翼深松铲和不带侧翼深松铲的耕作阻力及深松后的土壤剖面。结果表明,深松铲前进方向的阻力随安装角的增加而加大,由于深松铲侧翼的宽度比铲头宽,使土壤内部形成分层构造,扩大深松铲的松土范围,同时提高土壤的保墒蓄水能力。  相似文献   

Establishment success of 25 rare wetland species introduced into restored habitats is best predicted by ecological distance to source habitats     

Florence Noël  Daniel Prati  Mark van Kleunen  Andreas Gygax  Daniel Moser  Markus Fischer 《Biological conservation》2011,(1):602-609

In response to ongoing local extinction of species and the current biodiversity crisis, the number of reintroduction programs aiming to establish new populations of rare species in the wild has increased. However, only a small proportion of these programs has been planned and monitored scientifically and comparative multi-species studies are missing in this context. Therefore, the relative importance of factors involved in reintroduction success is poorly known. In 2007, we assessed population growth since introduction as a measure of establishment success of 25 wetland species (rare or extinct in the wild nationwide) and a total of 50 populations in Switzerland that had been introduced at seven restored sites with apparently adequate environmental conditions between 1997 and 2005. We related establishment success to 32 life-history traits of these species obtained from the BiolFlor database, to initial number of introduced plants (propagule pressure with 1–130 individuals introduced per population), and to the ecological distance between source sites and restored sites based on vegetation records. Our results clearly showed the importance of close ecological similarity between source and introduction sites for successful establishment of wetland species into restored pond habitats. In contrast, neither life-history traits nor propagule pressure were related to establishment success in our study. Based on our results, we strongly recommend enforcing ecological studies prior to reintroduction to accurately assess the suitability of restored sites. To unambiguously assess the key determinants of successful establishment, future reintroduction programs should be set-up according to experimental designs.  相似文献   

高寒牧区混播草地建植技术研究   总被引：1，自引：0，他引：1  

张榕  高占琪  豆卫  马龙喜  阿不满  曹国顺  孟祥君 《草业科学》2011,28(8):1512-1516

摘要：2004－2006年在甘肃甘南州夏河县桑科乡开展豆科和禾本科牧草不同草种组合混播试验研究,结果表明,建植第1年(2004年)组合Ⅱ[甘肃红豆草（Onobrychis viciaefolia cv.Gansu）、阿尔冈金苜蓿(Medicago sativa cv.Algonguin)、垂穗披碱草(Elymus nutans)和无芒雀麦(Bromus inermis)]产草量最高,比组合Ⅰ(甘肃红豆草、阿尔冈金苜蓿和垂穗披碱草）、组合Ⅲ（甘肃红豆草、阿尔冈金苜蓿和无芒雀麦）和组合Ⅳ（甘肃红豆草和阿尔冈金苜蓿）分别多产干草379、446和369 kg/hm2,组合Ⅱ与其他组合之间差异显著(P<0.05)。建植第2年（2005年）组合Ⅰ、组合Ⅱ、组合Ⅲ和组合Ⅳ干草产量分别为2 489、2 856、2 715和2 976 kg/hm2,各组合之间差异不显著(P>0.05)。建植第3年（2006年）组合Ⅳ（甘肃红豆草、阿尔冈金苜蓿）鲜草、干草产量最高,比组合Ⅰ多产干草3 635 kg/hm2,各组合之间差异显著(P<0.05)。  相似文献   

我国华东地区猪繁殖与呼吸综合征病毒流行株NSP2基因的遗传变异分析     

王兴龙  李玉峰  周业飞  王先炜  姜平 《中国预防兽医学报》2011,33(4)

为研究猪繁殖与呼吸综合征病毒(PRRSV)在我国华东地区的遗传变异情况和发展趋势,本研究对2004年～2009年分离鉴定的38株PRRSV流行株NSP2基因高变异区进行序列测定及分析.38株PRRSV分离株核苷酸同源性为71.6%～99.6%,推导的氨基酸同源性为63.7%～98.3%,共分为5种基因缺失类型.系统进化分析表明:38个分离株按基因序列可分为NSP2基因亚型Ⅰ和Ⅱ,其中,28株属于NSP2基因亚型Ⅰ,各病毒株均具有至少30个氨基酸的缺失,基因同源性为92.9%～99.2%;10株属于NSP2基因亚型Ⅱ,均具有1个或不具有氨基酸的缺失,基因同源性为76.5%～99.6%.流行株显示由基因亚型Ⅱ逐渐向基因亚型Ⅰ变异的趋势,并且NSP2核苷酸的缺失数量呈上升趋势.由此显示,我国PRRSV流行株NSP2基因变异较大,并不断出现新的变化,因此,加强PRRSV流行株基因变异的监测十分必要.  相似文献   

长春地区六种绣线菊属植物耐旱性比较研究     

李杰  金研铭  王洪涛  马丽华  刘世荣 《北方园艺》2011,(10):56-59

通过对6种绣线菊属植物叶片含水量、电导率、丙二醛(MDA)、可溶性糖含量的测定,运用综合分析的方法进行耐旱性评价研究。结果表明:6种供试品种的耐旱性排序如下:珍珠绣线菊>日本绣线菊>柳叶绣线菊>毛果绣线菊>珍珠梅>金山绣线菊。  相似文献   

香根草对盐碱土壤修缮改良作用的研究   总被引：1，自引：0，他引：1  

邱清华  邓绍云 《北方园艺》2011,(17):169-171

以香根草为试材,采用人工配置含有一定浓度的NaCl或K2CO3盐碱的土壤为栽培基质,统计分析了香根草的成活率、分蘖率和生物量积累率,与香根草植株体内的盐分含量及栽培土壤中盐碱含量,并进一步测定了所栽培的香根草吸收土壤中盐分的质量和能力及土壤中减少的盐碱质量.结果表明:香根草对土壤中盐碱的吸收能力较强,在其生长发育过程中氯盐的吸收能力大于对碳酸盐的吸收;但对于土壤中的盐碱降解来说,碳酸盐的降解比氯盐容易;同时得出香根草对于盐碱土壤具有一定的修缮改良作用.  相似文献   

中国盐碱土壤修复研究综述   总被引：9，自引：1，他引：8  

邓绍云  邱清华 《北方园艺》2011,(22):171-174

综述了中国土壤盐碱化的严峻现实,分析了土壤盐碱化的成因,并归纳了中国土壤盐碱化的类型.回顾了近年来中国盐碱土壤修复的历程和研究成果,归纳了盐碱土壤修复的方法且评述了其各自特性,分析了各自修复方法的优点和缺点,肯定了成绩,指出了不足.最后,对盐碱土壤的修复指明了正确方向,并提出了较高的期望.  相似文献   

赴美国竹业考察报告   总被引：6，自引：1，他引：5  

吴良如  王恩苓 《竹子研究汇刊》2003,22(2):9-14

全面介绍了美国竹业发展的历程和现状，对开展中美双边竹业合作及多边合作提出了一些建设性建议。  相似文献   

The Effect of Damage to the Root System Caused by Inter-Row Cultivation on Growth of Maize     

H. M. G. van der  Werf M. Tollenaar 《Journal of Agronomy and Crop Science》1993,171(1):31-35

Inter-row cultivation of a weed-free maize crop may affect yield. This study was done to establish whether inter-row cultivation damages crop roots in maize ( Zea mays L.) and to assess the effect of root pruning on growth and yield. In 1986 and 1987 inter-row cultivation and root cutting treatments were applied to field-grown maize crops in three experiments. Growth analysis revealed that the crop responded differently to the treatments in each trial. Measuring xylem exudate shortly after application of the treatments as an estimator of root damage proved useful in explaining crop responses. In one experiment no root damage occurred and crop growth was not affected. When root damage did occur (in the other two experiments), dry matter yield 3 weeks after treatments was found to be related to xylem exudate yield shortly after the treatments. A reduction of xylem exudate of 1 g/h per plant was associated with a reduction of 360 to 700 kg/ha in whole plant dry matter. In one of these experiments the effect of root damage in whole plant dry matter yield remained until final harvest; in the other experiment all treatments had similar yields at final harvest.  相似文献