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。     

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。     

林业经济发展与气候因素的因果关系

森林资源是林业经济发展的基础能源,又与气候存在着因果关系.气候因素中的气温、湿度、降水、光照等对森林生长产生起决定性影响,林业生产总值深受气候影响,同时林业经济的发展可能对气候产生正反两方面作用.因此,人们在发展林业经济过程中要考虑到气候变化因素,积极发展木本油料能源产业.     

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.     

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。     

艺术设计中“图”与“底”的关系

人们关注的中心为“图”,背景的部分为“底”,“图形”与“基底”的关系指一个封闭的式样与另一个和它同质的非封闭的背景之间的关系。图底关系理论在城市建筑设计中大有可为。     

The Buyer Cancellation Claim and the Tenant Priority Claim in Auction--Analyzing the Disputes in An Auction Case

Two problems often appear in estate auction.The first is to whom the buyer can claim cancellation of the contract,if he can't get the estate.The second is whether the tenant can still claim his priority to the estate.In auction,we can't use the principle of agency,fiduciary and mediation to explain the relations among client,auctioneer and buyer,because it doesn't accord with the auction practices and the Action Law section 40.The undisclosed agency in Contract Law may be an adapt explanation to the relations.According to the law hermeneutic,we should narrow the scopes of the tenant priority and exclude it from auction.     

Is partial root-zone drying an effective irrigation technique to improve water use efficiency and fruit quality in field-grown wine grapes under semiarid conditions?

We investigated the effects of partial root-zone drying (PRD) applied at different periods on leaf water relations, vegetative development, fruit yield, must and wine quality in wine grapes (Vitis vinifera L. cv. Monastrell) during a 3-year field experiment in order to determine the importance of the timing of PRD application on physiological and agronomical vine response under semiarid conditions. Two irrigation treatments were applied: conventional drip irrigation (CI) and PRD. Both treatments received the same annual water quantity. Each year the PRD treatment was applied at different periods of the growth cycle. In 1999 PRD was applied from veraison to harvest (end July–early September); in 2000 from fruit set to harvest (mid June–early September); and in 2001 PRD from budburst to harvest (mid April–early September). Leaf water relations and gas exchange during the experimental period were not significantly affected by PRD treatment. In 1999 and 2000 there was no significant treatment effect on vegetative development, yield or fruit quality. However, in 2001 (when PRD was applied from budburst to harvest), reproductive and vegetative development was clearly altered in PRD vines. Fruit set percentage and vegetative development (shoot length, pruning weight and primary and lateral leaf area) were significantly increased in PRD vines compared to CI. This resulted in both higher yield (kg per vine) (43%) and water use efficiency (40%) compared to CI vines. Berry number per cluster and cluster weight were also significantly increased in PRD vines. Notwithstanding higher yield in PRD vines and a similar berry size, the must and wine quality was not significantly altered, indicating a higher synthesis and accumulation of photoassimilates and metabolites in the berries of PRD vines. We conclude that there was an positive effect on vegetative and reproductive growth when long-term PRD was applied from the beginning of growing season (budburst), suggesting that early onset of PRD is desirable to intensify PRD response under these semiarid conditions. Nevertheless from these results we need to further investigate the long- and short-term effects of PRD, with moderate water amounts, on vegetative and reproductive development such as flowering and fruit set processes in wine grapes.     

NUTRIENT UPTAKE,PHYSIOLOGICAL RESPONSES,AND YIELD ATTRIBUTES OF WHEAT (TRITICUM AESTIVUM L.) EXPOSED TO EARLY AND LATE DROUGHT STRESS

The response of different wheat cultivars to drought imposed after three and six weeks of seedling emergence was evaluated in the wire house. The seeds of recommended local wheat cultivars were sown in plastic pots. The drought stress decreased the water relation, nutrient uptake and grain yield of all the wheat cultivars. The early drought stress significantly reduced the nitrogen (N) uptake by 38% while late drought stress decreased nitrogen uptake by 46%. The phosphorus (P) and potassium (K) uptake were decreased by 49% and 37% under early drought stress, respectively while their uptake was decreased by 51% each under late drought stress. Grain yield was reduced by 24% under early drought stress while it was reduced by 60% under late drought stress. Water deficit at early growth stages reduced grain weight by 10% while it was reduced by 35% under water deficit at later stages of growth.