美国高冰草兰州引种栽培试验

试验研究了美国高冰草在我国黄土高原半干旱区兰州的生长特性、农艺经济性状、植物量等。结果表明:美国高冰草在一般管理条件下能较好的适应兰州地区的土壤气候条件,可大面积种植繁育,并可在黄土高原类似地区作为优良牧草和生态建设草种推广使用。     

水分条件对巴音布鲁克高寒湿地CO_2排放的影响

在新疆天山中部巴音布鲁克天鹅湖高寒湿地,以苔草(Carex tristachya)为主要建群种的样地为研究对象,利用英国PP-systems公司生产的便携式土壤呼吸测定系统(CIRAS-2-SRC)研究了不同地表水分条件对天鹅湖高寒湿地夏季土壤CO2排放的影响。结果表明,1)湿润区的生物量大于干燥区;干燥区土壤CO2排放高于湿润区,干燥区土壤CO2排放日变化曲线为单峰曲线,CO2排放最高点出现在当地14:00-16:00,最高值为1.185 0g CO2·m-2·h-1;湿润区土壤CO2排放日变化曲线为双峰曲线,两个峰值分别出现在12:00和16:00,最高值为1.024 0g CO2·m-2·h-1。2)不同水分条件下生物量中凋落物含量影响土壤CO2排放。土壤温度是CO2排放的主要限制因子,且地表干燥区CO2排放与土壤温度的相关性更显著(P0.01)。土壤湿度与CO2排放相关性不显著(P湿润区=0.997,P干燥区=0.409)。     

美国农业保护性耕作技术的启示

为了学习与引进先进的保护性耕作技术,阐述了美国保护性耕作的起源,说明了传统耕作给农业生产带来的毁灭性的打击,并通过以免耕为主的保护性耕作的论述,进一步说明了黑龙江省耕作制度改革的必要性。同时通过美国先进耕作制度的论述,提出了黑龙江省发展保护性耕作制度的必要性和具体措施。     

宁夏绿洲禾豆牧草混播组合及其比例效应

在宁夏中部半干旱带有补灌的条件下,以紫花苜蓿(Medicago sativa)、沙打旺(Astragalus adsurgens)、羊草(Leymus chinensis)和老芒麦(Elymus sibiricus)为试验材料,豆科与禾本科牧草分别按照3∶7、5∶5、7∶3共3种不同比例进行混播,研究了不同混播组合及比例对其经济投入产出比、干草及主要营养成分产量、相对总产量及竞争力等方面的影响。两年的试验结果表明,3种豆禾牧草混播比例的产量均显著大于单播禾本科牧草的产量(P0.05)。苜蓿与禾本科牧草混播组合2013年及2014年的产量均显著高于沙打旺与禾本科牧草的混播组合(P0.05),其中,紫花苜蓿∶羊草为7∶3的混播组合的产量为最高(P0.05),粗蛋白和粗脂肪的总产量最高且投入产出比最低。紫花苜蓿+禾草组合中豆科牧草竞争力均大于相同比例下沙打旺+禾本科牧草组合中豆科牧草竞争力。沙打旺+禾本科牧草混播组合中,相对总产量(RYT)大于1的组合多于紫花苜蓿+禾本科牧草混播组合,其中,沙打旺∶羊草为7∶3的混播组合的两年平均RYT最高。以上结果说明,在宁夏中部半干旱带建植栽培草地时,紫花苜蓿∶羊草为7∶3的混播组合有较好的产量效应和最低的投入产出比;而沙打旺∶羊草为7∶3的混播组合中不同物种生长较为均衡。     

90年来中共历代中央领导集体政治交接简评

中国共产党成立90年来一共形成了四代成熟而稳定的中央领导集体。其中,第一、二代领导集体围绕最高领导权力的交接不甚成功,但从总体上讲,四代领导集体之间基本实现了正常的交接,并不断走向制度化。这是党自身能够健康发展,党领导的革命和建设事业兴旺发达的根本保证。     

美国农产品分布对我国农产品区域发展的影响研究

美国农业一直处于领先地位,不仅得益于其丰富的自然资源和高科技的农业技术,其合理的农产品分布也不可少的影响因素。中国是一个农业大国,农业的发展离不开农产品,农产品的种植种类、农产品的区域分布、农产品的质量发展都直接影响农产品的发展。美国虽然面积和我国差不多,但因为有合理的布局,农产品贸易一直发展良好。要借鉴美国农产品的发展,研究和分析其农产品分布现状很有必要。     

Prevalence,molecular characterization and risk factor analysis of Ehrlichia canis and Anaplasma platys in domestic dogs from Paraguay

This is the first study to investigate the prevalence and risk factors associated with Ehrlichia canis and Anaplasma platys positivity in dogs from Paraguay. Conventional PCR assays for the E. canis 16SrRNA gene and A. platys p44 gene were carried out in blood samples from 384 dogs from Asunción city, Paraguay. Sequencing and phylogenetic analysis were performed in selected positive E. canis and (16SrRNA gene) and A. platys (16S and p44 genes) samples. The overall prevalence of E. canis and A. platys in dogs in Paraguay was 10.41% (40/384) and 10.67% (41/384), respectively. Older dogs without veterinary care had higher odds for E. canis positivity and a higher number of dogs in the same household, as well as absence of anti-tick treatment were considered risk factors for A. platys. Ehrlichia canis and A. platys circulate in the dog population from Asunción, and are described for the first time in Paraguay.     

Anthropogenically disturbed potentially toxic elements in roadside topsoils of a suburban region of Bishkek,Central Asia

The ecological environment in Central Asia is vulnerable to pressure from human activity due to the physical geography and climatic fragility of this region. A set of indicators suitable for the future assessment of this pressure needs to be proposed. Thirty‐six topsoil samples (0–5 cm) were collected from roadsides in a suburban region of Bishkek, the capital of the Kyrgyz Republic in Central Asia, and a risk assessment of anthropogenically disturbed potentially toxic elements (PTEs) was systematically conducted with classic statistical methods. The results of detrended correspondence analysis and principal component analysis clearly showed that topsoil samples with high contents of PTEs (Pb, Zn and Cu) were strongly affected by traffic within a distance threshold of 200 m and that anthropogenic effects decreased significantly with increasing distance from the highway. The enrichment factor and anthropogenic contribution for Pb were the highest among the three PTEs, with average values of 2.0% and 47.4%, respectively, suggesting enrichment. However, the results of the human health risk assessment also indicated that noncarcinogenic risks did not occur for any of the anthropogenic PTEs. The reported method provides a new systematic pathway to reveal anthropogenic influences on the geochemical composition of soil. The conclusions of this work will be highly valuable as important guidelines for agriculture, and the results of the PTE contents will provide a scientific basis for soil collection in future studies.     

中美体育慈善现状的比较研究

美国体育慈善有着良好的慈善文化背景、税收激励和管理制度，在参与意识、运营主体、运营规模 、活动方式、评估约束机制、组织等慈等方面都已经取得卓有成效的效果。中国体育慈善需要不断地吸取 美国已有的成熟经验，扩大慈善参与形式，完善慈善制度建设，逐步养成中国体育明星慈善参与的道德责 任和习惯，实现国内体育慈善蓬勃发展的新局面。