用新思路建设和管理实验室   总被引：8，自引：0，他引：8  

刘伟 《农业网络信息》2006,(2):83-84

科学技术和高等教育的发展，促使我们努力以新思路建设实验室、以高水平管理实验室。把握实验技术发展的动向才能保证实验室建设和实验教学内容的先进性。营造良好的开放式实验教学环境和条件是培养跨世纪人才关键。教学资源的信息化、网络化管理已纳入到我们的管理工作之中。  相似文献   

京郊露地菜田施肥状况与土壤有效养分年际变化调研     

文方芳  贾小红  廖洪  王胜涛  于跃跃  梁金凤  李旭军  刘自飞 《中国蔬菜》2015,1(10):63-67

以北京市1996~2014年郊区露地菜田1184份调研报告和161个土壤样本数据为基础,分析了京郊露地菜田施肥种类、施肥量、养分平衡、土壤有效养分的年际变化。结果表明:与20世纪90年代相比,现阶段露地菜田施用的有机肥由以厩肥、鸭粪和牛粪为主转为以鸡粪为主,化肥投入品种单一,偏施大量元素肥,缺少中微量元素补充;与20世纪90年代相比,尽管现阶段年施肥量明显减少,年养分盈余程度明显减轻,但养分投入量仍与作物吸收规律不符,N、P、K三大元素投入比例不合理,氮磷养分盈余的现象仍存在。经评价现阶段露地菜田土壤碱解氮缺乏,速效磷含量过高,有效钾适宜。  相似文献   

Geographic associations of breeding bird distribution in an urban open space     

Daniel S Cooper 《Biological conservation》2002,104(2):205-210

The Puente-Chino Hills, extending west into the highly urbanized Los Angeles Basin, represent one of the largest expanses of lowland habitats in the region. During spring and early summer of 1997 and 1998, birds and vegetation surveys were conducted to clarify the influence of geographical position in the distribution of birds in the hills. Using logistic regression, the inclusion of longitudinal position as a variable is shown to make a statistically significant contribution to bird species presence beyond that of habitat alone for 12 of the 49 most commonly detected species. Species more common than would be expected based on habitat in the east were typical of grassland and open habitats, whereas those more common in the west were characteristic of tall scrub or urban habitats. Thus, species’ distributions in the hills are likely influenced by landscape-scale vegetation patterns and by the aggregate amount of urbanized areas in the west. This emphasizes the importance of using geographical position as a variable when analyzing patterns in bird distribution and siting conservation areas.  相似文献   

人参叶片光合作用日变化的研究   总被引：2，自引：2，他引：2  

徐克章  修立军 《吉林农业大学学报》1991,13(3):13-15

人参叶片光合作用的日变化,主要受冠层上部光照的影响,在遮荫棚下,呈单峰曲线型变化。气孔开闭、气孔导度和蒸腾作用一日中的变化与光合作用的日变化基本吻合。清晨至上午10时前,所测叶片净光合速率较高。这时,环境中CO_2浓度较高,湿度较大,温度适宜。同时,叶片内可溶性糖含量也较低。光合作用的加强可能是这些内、外因子综合作用的结果。透光率较大的荫棚下人参叶片一日中的光合速率也较高。  相似文献   

国家农业政策分析与决策支持系统项目研究回顾与展望     

秦富  王东阳  李锁平  吕开宇 《中国农业科学》2007,40(Z1):2956-2961

  相似文献   

人类生态系统的研究   总被引：1，自引：0，他引：1  

奈民夫 《内蒙古林学院学报》1998,20(3):50-59

非线性原理即熵定律分析人类生态系统中能量，流动，地球表层有三大类型开放系统，“人类只有一个地球”，人类行为规范化，协调人口，资源，环境和发展的关系。  相似文献   

Analysis of the toxic potential of Palicourea corymbifera (Müll. Arg.) Standl. in laboratory animals     

Ribeiro de Assis JC  Suffredini IB  Moreno PR  Young MC  Varella AD  Younes RN  Bernardi MM 《Research in veterinary science》2006,80(2):209-217

Palicourea species may produce bovine toxicity. Palicourea corymbifera grows in terra firme forests within the Amazon rain forest and in Tropical America, particularly in spots that gave place to gazing areas. The lyophilized extract done with the aerial organs of P. corymbifera were analyzed in male and female mice. Results revealed a significant toxicity: LD50 was 1.10 (1.04-1.15)g/kg for male mice, and 1.05 (1.00-1.10)g/kg for female mice. Locomotion was affected as well as there were reflexes linked to environmental stimuli in addition to changes in posture. Progressive central nervous system stimulus signs such as trembling and convulsions were detected, the latter followed by the animal's death. Macroscopic histopathological exams performed on the liver, kidneys and lungs of mice submitted to necropsy did not indicate the existence of lesions. General activity of animals, measured in an open field, was reduced as a result of the administration of the extract. Duration of locomotion and rearing frequency were reduced, in opposition to an increase in the duration of immobility. Thin layer chromatography analysis showed that monofluoroacetic acid is present in the lyophilized extract, but other qualitative techniques as gas chromatography/mass spectrometry and 19F nuclear magnetic resonance showed that the MFAA was not present in the extract, and that the toxicity is related to other compound, although the toxic profile is very similar to that of MFAA. P. corymbifera was shown to be significantly toxic to laboratory animals and investigation of the possible toxic substance shall be done.  相似文献   

宁夏设施与露地土壤理化性状对比     

何进勤  桂林国  何文寿 《西北农业学报》2012,21(10):202-206

根据宁夏灌区温室的分布状况,采集设施栽培与露地栽培表层(0~20 cm)土壤,对同地域设施土壤与露地土壤进行对比分析。结果表明,宁夏设施土壤,在物理性状上与露地土壤相比水稳性团聚体显著增加,而土壤体积质量显著降低,通气孔隙度、田间持水量和自然水质量含量增加较小,未达到显著差异;在化学性状上,设施土壤有机质、全盐以及碱解氮、速效P、K质量分数均显著提高,而pH显著降低,微量元素质量分数除有效Fe显著提高外,有效B、有效Zn、有效Mn、有效Cu均升高不明显,但是土壤有效Zn和有效Cu质量分数与其背景值相比均在高指标范围内,因Zn和Cu都属于重金属元素,因此,在确定施肥量及农事操作时应重点予以考虑。  相似文献   

河北省高校对开放获取资源利用的调查分析     

周志霞  李树霞 《农业图书情报学刊》2012,24(12):25-27

利用问卷调查的方法对河北省高校教师、科研人员及硕博士研究生进行了开放获取资源的认识与期望等利用方面的问卷调查。  相似文献   

图书排架方法的继承与创新：兼与蒋鸿标、王旭艳商榷     

李三保 《农业环境科学学报》2012,31(1)

在分析蒋鸿标的“细分粗排”和王旭艳的“细分细排”图书排架方法的基础上,针对开架图书借阅乱架问题,提出了“两号分离”法,并介绍了“两号分离”法的原理、优点、可行性和使用“两号分离”法需注意的问题。  相似文献