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91.
为探索适于滴灌的甜菜种植密度及节水灌溉技术,2011年进行了淹灌与滴灌以及滴灌条件不同密度处理对甜菜产量、含糖率及根腐病发病率的影响试验.结果表明,滴灌比淹灌甜菜根腐病发病率低2.3%~2.7%,节水46.9%~64.0%,甜菜整个生育期可节水5567.5m3/hm2,根产量、含糖率都有所提高;滴灌甜菜较适宜密度为8.25~9.75万株/hm2.  相似文献   
92.
AIMS: To determine factors that may influence the efficacy of an oral pelleted vaccine containing Mycobacterium bovis bacille Calmette-Guérin (BCG) to induce protection of brushtail possums against tuberculosis. To determine the duration of protective immunity following oral administration of BCG.

METHODS: In Study 1, a group of possums (n=7) was immunised by feeding 10 pellets containing dead Pasteur BCG, followed 15 weeks later with a single pellet of live Pasteur BCG. At that time, four other groups of possums (n=7 per group) were given a single pellet of live Pasteur BCG orally, a single pellet of live Danish BCG orally, 10 pellets of live Pasteur BCG orally, or a subcutaneous injection of live Pasteur BCG. For the oral pelleted vaccines, BCG was formulated into a lipid matrix, and each pellet contained approximately 107 colony forming units (cfu) of BCG, while the vaccine injected subcutaneously contained 106 cfu of BCG. A sixth, non-vaccinated, group (n=7) served as a control. All possums were challenged by the aerosol route with a low dose of virulent M. bovis 7 weeks after vaccination, and killed 7–8 weeks after challenge. Protection against challenge with M. bovis was assessed from pathological and bacteriological findings.

In Study 2, lipid-formulated live Danish BCG was administered orally to three groups of possums (10–11 per group), and these possums were challenged with virulent M. bovis 8, 29 or 54 weeks later. The possums were killed 7 weeks after challenge, to assess protection in comparison to a non-vaccinated group.

RESULTS: The results from Study 1 showed that vaccine efficacy was not adversely affected by feeding dead BCG prior to live BCG. Feeding 10 vaccine pellets induced a level of protection similar to feeding a single pellet. Protection was similar when feeding possums a single pellet containing the Pasteur or Danish strains of BCG. All vaccinated groups had significantly reduced pathological changes or bacterial counts when compared to the non-vaccinated group. In Study 2, oral administration of Danish BCG induced protection against challenge with M. bovis, which persisted for at least 54 weeks after vaccination. Some protection was observed in possums challenged 54 weeks after vaccination, but this protection was significantly less than that observed in groups vaccinated 29 or 8 weeks prior to challenge. There was a strong relationship between the proportion of animals producing positive lymphocyte proliferation responses to M. bovis antigens and protection against challenge with M. bovis.

CONCLUSIONS: Factors considered potentially capable of interfering with vaccination, including feeding dead BCG to possums prior to feeding live BCG, feeding multiple doses of BCG at one time, and changing strains of BCG, were shown not to interfere with the acquisition of protective immune responses in possums. Protection against tuberculosis was undiminished up to 29 weeks after vaccination with BCG administered orally. It is concluded that vaccination of possums by feeding pellets containing BCG is a robust and efficient approach to enhance the resistance of these animals to tuberculosis.  相似文献   
93.
AIM: To determine whether drenching regimes for lambs by which a proportion (10%) of the heaviest animals was selectively left untreated, or animals are only drenched ‘on demand’ when faecal nematode egg counts (FEC) exceeded a threshold level, would result in measurable increases in parasite larval challenge in the autumn and/or decreases in the performance of lambs.

METHODS: A replicated study compared three drenching strategies in which mobs of lambs (n=360 in total) received either: a five-drench preventive programme, administered to all animals (Treatment 1); a five-drench preventive programme, but the 10% heaviest animals left untreated each time (Treatment 2); or drench treatments administered only when FEC exceeded 500 eggs per gram of faeces (epg) (Treatment 3). After the five-drench programme, animals in Treatments 1 and 2 were treated according to FEC as for Treatment 3. A triple-combination drench containing ivermectin, oxfendazole and levamisole, administered orally, was used for all treatments. There were nine farmlets, allowing three replicates of each treatment, in a completely randomised design. Parasite infestations on pasture were measured in autumn by pasture plucks, and worm burdens were monitored in tracer lambs, while the performance of lambs was assessed by liveweight gains, fleece weights, and body condition and dag scores.

RESULTS: Increased numbers of Haemonchus contortus and Trichostrongylus colubriformis larvae on pasture were found in the autumn on farmlets treating selectively or on-demand (Treatments 2 and 3). No differences were detected in other parasite species. Mean liveweight gains did not differ between treatments but some differences were detected between drenched and undrenched lambs in Treatment 2. Mean body condition and mean dag scores of lambs in Treatment 3 tended to be lower and higher, respectively, than those of lambs in Treatment 1; Treatment 2 was generally intermediate.

CONCLUSIONS: Drenching strategies for lambs designed to slow the development of anthelmintic resistance, by increasing the pool of susceptible worms available to dilute resistant survivors after treatment, resulted in increased numbers of H. contortus and T. colubriformis but not other species of parasite on pasture. The increased parasite challenge to lambs in the autumn was associated with small production losses, which may be acceptable to farmers wishing to implement such strategies. It is clear that further work is required on the interaction between management practices and the population dynamics of parasites, especially with regard to creating pools of susceptible genotypes to slow the development of drench resistance.  相似文献   
94.
以呼伦贝尔草原四种不同草地类型牧草为研究对象,分别对其进行单贮、混贮处理,研究不同青贮处理对不同草地类型牧草长链脂肪酸的构成及含量的影响.结果表明:四种草地类型不同处理样品所含长链脂肪酸的成分相同,都以亚麻酸和棕榈酸为主,亚油酸含量也比较高;四种草地类型不同处理间各长链脂肪酸的含量均有所差异,混贮处理对各长链脂肪酸含量变化的影响最大.混贮处理后贝加尔针茅硬脂酸(P<0.01)、亚油酸(P<0.05)的含量明显升高,油酸明显下降(P<0.05);四种草地经不同处理后同一草地类型取样点之间长链脂肪酸含量的差异不大.  相似文献   
95.
内蒙古自治区与相关区域构成了一个复杂、开放的区域系统,其内部主要由自然区、行政区、主体功能区等组成;区域协调内容包括内蒙古自治区与全国的协调、内蒙古自治区东部与西部的协调、呼和浩特、包头、鄂尔多斯(简称呼包鄂,下同)三市协调、内蒙古自治区与俄罗斯等国家的协调、内蒙古自治区与相关省市自治区的协调、自然区与行政区的协调、行政区与主体功能区的协调、城市与农牧区的协调等;存在着许多社会经济指标低于全国平均水平、东部与西部社会经济等方面差距过大、出口依存度太低与外贸逆差过大、与相关省市自治区自然资源及产业的互补性差、地方利益与流域全局利益矛盾尖锐、主体功能区跨界缺乏统一领导、呼包鄂三市产业同构化现象趋于明显、城乡差距过大等问题;应该采取加强内蒙古自治区区域协调研究、编制区域协调规划、建立区域协调组织、利用调控手段促进区域协调发展和构建区域协调内在机制等对策.  相似文献   
96.
再植枸杞根际真菌群落对长期连作的响应研究   总被引:1,自引:0,他引:1  
受枸杞自身种植特点和道地产区土地资源限制,连作障碍已成为制约宁夏枸杞产业可持续发展的主要因素之一,导致严重的经济损失和生态问题。前期研究表明,连作能够显著影响再植枸杞根际土壤细菌的群落结构和多样性,但就连作对真菌群落结构和功能的影响目前仍不清楚。本文利用实时荧光定量PCR和高通量测序技术,研究连作对再植枸杞根际真菌群落丰度及多样性的影响。实时荧光定量PCR分析表明,与对照样地相比,连作显著促进再植枸杞根际及非根际土壤中细菌和真菌的丰度。但连作对真菌的促进作用明显高于细菌,导致细菌/真菌比例失衡,使再植枸杞根际及非根际土壤微生物环境偏向于真菌型。对测序结果的分析发现,所测定样地中枸杞根际及非根际土壤中的优势真菌门分别为子囊菌门、担子菌门、接合菌门、壶菌门及球囊菌门,其中连作地再植枸杞根际子囊菌门的相对丰度较对照样地显著降低,而接合菌门的相对丰度则显著增加(P0.05)。FUNGuild真菌功能预测也证实连作显著抑制再植枸杞根际土壤丛枝菌根真菌的相对丰度(P0.05)。基于距离的冗余分析(db-RDA)结果表明,土壤pH、电导率、硝态氮和有效磷含量是影响枸杞根际土壤真菌群落变化的主要因子(P0.05),而土壤硝态氮和有效磷含量则是解释非根际土壤真菌群落变化的主要因子(P0.05)。这些结果说明长期施用化肥可能是改变连作地再植枸杞根际土壤真菌群落结构及枸杞-真菌互作关系的主要因素之一。这一研究结果为理解枸杞连作障碍的形成机制提供理论基础。  相似文献   
97.
乡土野花组合是筛选以乡土野花为主体的,并通过混合播种建立群落的一种景观植被建植模式,是欧美国家近年来较为流行的一种农业景观恢复与建设的技术措施。已有的研究发现乡土野花组合能够改善景观结构与生境质量,吸引传粉生物和自然天敌,从而起到增强农业景观的传粉及害虫控制功能,并改善农作物品质、提高农作物产量;与此同时,乡土野花组合也具有较好的文化功能。乡土野花组合的设计对建植效果具有重要作用,其物种筛选、配比、播种方式及布局是设计中需要主要解决的问题。本文在总结欧美国家乡土野花组合设计模式与生态监测结果的基础上,提出乡土野花组合物种筛选的3原则:乡土性、功能多样性与包含特定关键物种;并对其生长周期、物种数、播量、播种面积与空间布局等技术细节进行了讨论,以促进乡土野花组合的本土化、区域化发展。欧美国家提出了一系列推动产业发展及农户补贴的有关政策,其中美国主要以推动基础研究与产业发展政策为主,注重限制植物材料本土化;欧洲国家通过多项立法及农业环境管护政策为农户提供多样化的生态补贴,以促进农户充分参与乡土野花组合栽植过程。在我国,尚缺乏成熟的乡土野花组合应用案例。中国的乡土野花组合需充分发掘种质资源并进行生态、栽培与景观特性评估,以实现本土化的乡土野花组合。本文最后提出,通过多学科合作实现乡土野花组合的设计与推广,政府、产业、科研机构与农民共同参与乡土野花组合的设计过程,并提出市场化的生态补贴政策,以推动乡土野花组合在我国农业景观的应用,为改善我国农业生态环境做出应有贡献。  相似文献   
98.
在水稻生产机械的产业化中,相关的知识产权问题乃是众多法律问题中的基础性问题,而所进行的与水稻生产机械相关的专利权检索则为黑龙江省制定相应的知识产权战略提供了基础性数据,使最终的战略制定更为科学。在对相应检索范围进行框定,检索数据进行筛选、整理与分析的基础上,得出相应的科学结论,并从如何提高黑龙江省专利申请水平、加强各方主体的职能与合作、保护农民权益等角度提出了建议。  相似文献   
99.
运用AMMI模型.结合双标图对2007年国家中晚熟西北组马铃薯品种区域试验各承试点的平均产量结果进行分析.试验结果表明,在参试品种中,L0031-17、青薯6号高产但不稳产,陇薯3号为高产稳产型,品种960102、中9931-48稳产但不高产,8025-1不稳产又不高产.AMMI模型具体、直观、有效的综合评价,为马铃薯品种提供了一种比较好的分析方法.  相似文献   
100.
纳添仓 《中国蔬菜》2018,1(4):71-72
青薯11号是以同薯23号为母本,以青薯168为父本,通过有性杂交和系统选育育成的鲜食马铃薯新品种。中晚熟,出苗至收获107 d(天)左右;薯块椭圆形,粉红皮,薯肉黄色带红晕,芽眼浅;块茎淀粉含量17.96%,粗蛋白3.17%,VC240.3 mg·kg~(-1),还原糖0.279%。抗晚疫病。一般肥力条件下每667 m~2产量2 200~2 500 kg,高肥力条件下产量2 500~3 000kg。适宜在青海省各类地区种植。  相似文献   
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