中国北方棉区转基因抗虫棉对棉苗蚜及其两种天敌的影响（英）

2001年田间小区试验研究了转Bt基因棉和转双价基因(Bt+CpTI)棉对棉苗蚜及其天敌种群动态的影响;室内研究了转基因抗虫棉对两种棉蚜天敌的生物学影响.结果表明,转基因抗虫棉对棉蚜种群数量的影响不明显,未达显著水平.单作转基因棉田棉蚜发生期比麦套棉田提前5天左右,发生数量是麦套棉田的1.6倍,表明麦棉套作可有效的控制苗蚜的为害.室内研究表明,异色瓢虫对用Bt棉处理的的棉蚜的捕食量比对照增加22.0%,棉蚜茧蜂对用Bt棉处理的棉蚜的寄主率降低23.5%.     

北疆不同类型棉田节肢动物群落结构与多样性

运用群落生态学方法研究了北疆棉田不同邻作、灌溉方式对棉田节肢动物群落结构和多样性的影响及其在不同年份的变化趋势。结果表明,不同的邻作方式能改变棉田节肢动物群落结构,邻作小麦增加棉田天敌种类,邻作玉米增加棉田天敌个体数,对棉田害虫有较强的控制作用,而邻作西红柿作用相对较弱,生产上应充分利用邻作小麦和玉米的有利作用。2003年滴灌棉田节肢动物群落多样性指数(0.7250)和均匀度(0.2111)均大于沟灌棉田(0.1924、0.0605),群落更稳定;不同年份棉田节肢动物群落结构和多样性变化大,说明气候因素是影响节肢动物群落结构和多样性的主要原因。     

藏北高寒植被地上生物量与土壤环境因子的关系

用样带法研究藏北高寒植被地上生物量与土壤环境因子之间的关系,对高寒植被地上生物量和7个土壤指标进行相关性分析和回归分析,结果表明:高寒草原到高寒荒漠植被,群落组成逐渐趋于简单化.土壤环境因子影响高寒植被地上生物量,0～10cm土层的土壤有机碳、有效氮、全磷和速效磷与高寒植被地上生物量极显著正相关(P<0.01);10～20cm土层的土壤总有机碳和全磷与高寒植被地上生物量极显著正相关(P<0.01);20～30cm土层的土壤各环境因子与高寒植被地上生物量的关系均未达到显著水平.     

浅谈陕北优势杂果资源及开发利用

陕北杂果资源丰富,特色鲜明,市场前景广阔.本文介绍了陕北主要优势杂果的资源分布、生产现状以及存在问题,提出了陕北优势杂果资源的开发利用途径.     

The potential of intercropping as an alternative land use system in temperate North America

The success of many intercropping systems in North America is attributable to the generation of a short term return from an agricultural crop during the early, unprofitable years of a longer term crop that is fruit, nuts or wood. This highly-efficient use of land and related profitability are important not only in the development of intercropping systems per se, but also in other applications which have tremendous potential independent of profitability. For example, intercropping can be effectively used during the establishment phases of hardwood plantations where it is essential to have a high level of weed control, the costs of which are often recovered with the agricultural production. Intercropping can also be used to grow trees rapidly and with a form that can be easily integrated into recreational or park situations, or urban fringe areas. In an urban context, intercropping can be used to grow trees in agricultural areas that are likely to be developed where traditional forestry options are not appropriate and the value of younger, thrifty trees may enhance property values far in excess of the cash value of the wood.     

Landowner perceptions and the adoption of agroforestry practices in southern Ontario,Canada

A mail-out survey questionnaire was developed by the Agroforestry group at the University of Guelph to determine the level of awareness and interest in the adoption of agroforestry systems by landusers from four townships in Wellington County, Ontario. The questionnaire investigated: (1) the current level of knowledge regarding windbreaks, woodlots and plantations, intereropping, riparian plantations and silvipasture, (2) the present level of participation in each of these systems on-farm, (3) the perceived benefits and/or drawbacks of each of these initiatives with respect to total farm income, income diversity, land rehabilitation, land value/equity, soil/water conservation, labour intensity, overhead and return on the term of investment.The majority of respondents were familiar with conventional agroforestry systems such as windbreaks and woodlots/plantations (80%, 62% respectively), therefore the level of interest in the adoption of these practices was significant (74%, 66% respectively). Response rates were lower for silvipasture, riparian plantations and intercropping, most likely as result of the low level of familiarity with these practices (20%, 32%, 4% respectively). Respondents commented that agroforestry systems would have a neutral effect on farm income, and would increase land stewardship. In some cases, interested landusers indicated a willingness to participate in agroforestry systems even though they anticipated increases in overhead and labour intensity; however, this was only true if they held land stewardship as a priority. Landusers were more concerned with the economic aspects of agroforestry, as a determinant to the future adoptability of particular practices. Age, gender, farm operation and farm size were not correlated with the adoption of agroforestry systems.The success of agroforestry programs on farms in the study area is largely dependent on the attitudes and willingness of landusers to participate in non-traditional agricultural systems.     

Folklore medicinal plants of North Andaman Islands, India

The rural folk of North Andaman, India use the traditional medicine for their primary health care. Folklore medicinal uses of 72 interesting medicinal plant species along with botanical name, local name, family, habit, part used, disease for which the drug is administrated, mode of administration are presented. These 72 plant species which provide the crude drugs pertain to 67 genera and 43 families of Magnoliophyta from tropical rainforests. These plants used to cure 40 ailments. Most remedies were taken orally, accounting for 76% of medicinal use. Most of the remedies were reported to have been from trees (55.6%) and herb (22.2%) species. The most widely sought after plant parts in the preparation of remedies in the areas are the stem bark (33.8%) and root (23.9%).     

浙北地区薪炭林高产栽培研究

浙北地区薪炭林高产栽培研究＊葛万川周健关键词薪炭林栽培体系浙北地区富阳市位于浙江省北部，地貌属浙江西北部低山丘陵区，气候上属我国中亚热带北缘。它在长江下游，中、北亚热带丘陵山地中具有一定的代表性。薪柴是富阳市的主要能源，１９８５年全市耗柴３８万ｔ，占...     

Agroforestry systems in North America

Agroforestry systems in North America vary widely in terms of components (tree, forb, graminoid, and shrub species) and outputs. Most of the agroforestry systems used in North America have emphasized wood and livestock production. The objective of each system has been to produce annual and long term economic returns and sustainable yields. Inputs such as fossil fuels, fertilizers, herbicides and pesticides are relatively low compared to those used in conventional agriculture.Major agroforestry system types in each of eight North American regions are described. The major species used as vegetational components in each system are enumerated by region. The numerous variations in how these components are mixed have created an almost endless number of actual systems. Management problems and solutions, economic concerns, and system comparisons have also been addressed for each region.     

三种薇菜产品营养成分的分析与比较

以南薇菜干、北薇菜干、水煮薇菜为原料,对它们的水分、灰分、粗蛋白、粗纤维、粗脂肪、胡萝卜素、Vc、K、Na、Ca、Mg、Fe、Cu、Se等营养成分进行了分析。结果表明:水煮薇菜含水量最高达到85.7%,两种薇菜干的水分含量差异不显著,但与水煮薇菜水分含量有极显著差异。南北薇菜干灰分和K含量差异显著,水煮薇菜含量最低与两种菜干均有极显著差异;水煮薇菜的粗脂肪和胡萝卜素含量最低与南薇菜干都有极显著差异,南北薇菜干间只有粗脂肪含量差异显著。三种菜样间Ca含量都有极显著差异,但Fe含量差异都不显著。粗蛋白、粗纤维、Vc、Na、Mg、Se、Cu南北薇菜干间无显著差异,水煮薇菜含量最低与两种菜干都有极显著差异。