塔里木河中下游农户能流分析及生态经济分形特征

能流分析和分形理论是农业生态经济系统定性研究和定量分析的重要手段之一。把农户作为“分形元” ,以尉犁县兴平乡达西村 4 0个农户为研究对象 ,在绿洲农业生态系统能流分析基础上 ,对不同经营类型农户的生态经济特征进行分形研究 ,结果表明 :(1) 5类农户从总体上都显现生产经营结构单调 ,能量利用和转化链条短 ;牲畜养殖是唯一的次级生产系统 ,能量转化率低 ,增效不明显。 (2 )农田亚系统是农户生产力的主体 ,棉花生产现在和今后若干年内仍将是农户的支柱产业。 (3)基于农户分析的生态效益和经济效益之间没有相关关系 ;生态效益高 ,并不意味着经济效益也高 ,反之亦然。农户生产系统总体的生态经济协调发展水平不高。     

基于PRA的退耕还林农户行为动因的经济分析——以宁南山区原州区、彭阳县为例

通过参与性评估方法(PRA)对宁南山区原州区和彭阳县的98户农户进行了分层随机抽样调查,采用成本—收益方法对农户退耕还林还草的态度及农户的生态环境行为进行了分析,提出了通过调整农业产业结构,建立生态补偿机制、实施生态移民、建立风险分担制度和社会保障体系等创新机制,以改变农户的短期生态行为。     

生态安全对防止耕地隐性流失和保证粮食安全的意义

从生态安全的角度探讨了我国的耕地流失和粮食安全问题。笔者认为,生态退耕和农业结构调整所引起的耕地面积减少不应简单地算入耕地流失之列。应从大农业的角度看待农用土地在不同利用方式下的合理转换。畜牧业等农业内部产业的用地固然会减少粮用耕地的面积,但会减轻畜牧业以及人类消费对粮食的需求。各种形式的生态劣变是耕地资源流失和耕地质量下降的主要原因。生态退耕应看作是对土地资源的一种保护措施和对耕地资源贮备形式。由于国民生活水平的提高和食物结构趋于多样化,口粮在食物构成中的比例趋于减少,简单以粮食占有量来评价国家粮食安全形势是不够全面的。从人体营养需求、国家粮食生产能力、消费趋势、国际市场潜力等方面分析了我国的粮食安全问题。由于人口增长缓慢,利农政策及价格对粮食生产的刺激,以及国际粮食生产和市场的巨大潜力,我国的粮食安全不存在大的问题。     

黄土高原中南部农户农果复合生态系统的能值分析

应用生态经济系统能值分析理论与方法,以黄土高原中南部的延安市宝塔区北沟村、淳化县西坡村2村农户为研究对象,通过一系列能值指标,定量分析了农户农果复合生态系统的自然资源以及系统投入产出特征.结果表明:农户农果复生态系统的能值投入结构相似,辅助能的投入中不可更新工业能的投入比重最高,且以化肥投入为主,有机肥投入不足,应按适当比例增加有机能值的投入以提高系统的生态经济效益;农户农果复合生态系统生产优势度较高,但系统稳定性指教低,单位时间的劳动生产率较低,农果业生产水平有待提高;农户农果复合系统的能值产出率较低,能值投入率较高,对能源的利用效率较低,农果复合系统的环境资源进一步开发的潜力很大.提高农果复合系统的能值投入应当是提高资源的利用效率,加强农果业管理的科技含量和科学管理力度,使黄土高原中南部的果业生产走上健康持续发展的轨道.     

跃先村农业生态系统调控途径初探

通过分析跃先村农业生产系统的原有状况，按照生态和经济学原理，提出以种草养畜为突破口，对立“林草－家畜－粮食”，生产系统，推生科学种田和科学养畜，进而完整了系统结构，收到了良好的经济效益，社会效益和生态效益，对广大渭北旱塬及类似地区发展农业生产提供了科学的参考。     

宁夏黄土高原风沙区畜牧业发展的资源、环境问题及对策

本文对宁夏黄土高原风沙区着重从大农业生态经济系统中人口、资源和环境间协调的角度出发,探讨该区畜牧业的主要自然和人为限制因素及产生的问题,畜牧业发展的潜力及今后的主要对策等。     

宁南山区农业资源及合理利用的途径

本文论述了宁夏南部山区的土壤、土地、气候、种植业、林业、畜牧业资源特征,存在问题,并提出合理改良利用的途径及发展农林牧业生产的关键技术措施。     

人工饲草料地生产效能的研究

在牧区草料的匮乏严重阻碍着草地畜牧业的发展 ,牲畜头数增加 ,草地过牧 ,使生态环境遭受着严重破坏。选择了具有代表性的新疆天山北坡中段昌吉市阿什里哈萨克民族乡 ,对其畜牧业生产系统的草、家畜生产和能物流流转情况进行了研究。运用能物流高效持续利用原则和线性规划法 ,提出了切实可行的人工饲草料生产子系统的优化配置模式。结果表明 ,系统优化后 ,全年舍饲的载畜水平大大提高 ;人均年收入由现行系统的 1 70 2元增加到 5 4 86元 ;系统优化后不仅大大减轻了放牧对天然草地造成的压力 ,而且显著提高了土壤肥力 ,改善土质     

宁南旱区主体畜牧业—牛羊的发展探讨

依据宁南旱区的基本资源特点，分析该区畜牧业发展的历史、现状及今后中、近期国内外市场和回族群众的需要，提出畜牧业应以发展牛、羊为主体的草食家畜的发展战略，以及为实现战略目标应采取的主要举措：极力改善畜牧业赖以发展的基础条件；提高经营的综合效益；广泛应用经济杂交；坚持基地、体系建设；强化科研与科技推广力度。     

北方农牧交错带农业生态系统结构的能值分析——以准格尔旗为例

优化农业生态系统结构是改善区域生态环境、维护生态安全的重要途径。利用研究区统计年鉴数据,运用能值理论、方法,对准格尔旗农业生态系统的能值投入、产出结构和运行效率进行定量评估,评价环境资源对农业生态系统的影响与贡献,为农业生态系统结构优化提供理论依据。研究表明:(1)环境资源,尤其是可更新资源的能值投入对准格尔旗农业生态系统生产力的贡献最大。遵循适度规模原则,优化能值投入结构,提高环境资源利用效率,加强水土保持,同时发展集水型生态农业,推广现代农牧业是提高准格尔旗农业生态系统生产力的根本出路;(2)畜牧业是准格尔旗农业生态系统的支柱。发展草基畜牧业,构建可持续的生态经济范式,实施"农牧互促"方案,提高农牧业系统耦合度及其整体生产力,是发展准格尔旗农业生态系统生产力的战略方向;(3)准格尔旗农业生态系统对当地环境资源的依赖程度增加。增强系统同化作用,加大农业科技辅助能值投入,降低干旱灾害风险,提高农业生产力,是改善准格尔旗生态环境质量,促进区域可持续发展的重要举措。     

江西农业外来有害生物及其防治

在江西发生面积较大,危害较严重的农业外来入侵生物主要有水花生、水葫芦、豚草、加拿大一枝黄花、福寿螺等。它们的危害不仅造成农业减产和破坏生态,还可传播病害。对外来有害生物的防治,应采取农业防治、生物防治和化学防治相结合综合防治措施。     

Invasive species research in the United States Department of Agriculture-Agricultural Research Service

Invasive pests cause huge losses both to agricultural production systems and to the natural environment through displacing native species and decreasing biodiversity. It is now estimated that many thousand exotic insect, weed and pathogen species have been established in the USA and that these invasive species are responsible for a large portion of the $130 billion losses estimated to be caused by pests each year. The Agricultural Research Service (ARS) has responded with extensive research and action programs aimed at understanding these problems and developing new management approaches for their control. This paper provides an overview of some of the ARS research that has been conducted on invasive species over the past few years and addresses both different categories of research and some specific pest systems of high interest to the US Department of Agriculture.     

Top 20 environmental weeds for classical biological control in Europe: a review of opportunities, regulations and other barriers to adoption

Classical biological control remains the only tool available for permanent ecological and economic management of invasive alien species that flourish through absence of their co‐evolved natural enemies. As such, this approach is recognized as a key tool for alien species management by the Convention on Biological Diversity (CBD), the European and Mediterranean Plant Protection Organization (EPPO) and the European Strategy on Invasive Alien Species (ESIAS). Successful classical biological control programmes abound around the world, despite disproportionate attention being given to occasional and predictable non‐target impacts. Despite more than 130 case histories in Europe against insect pests, no exotic classical biological control agent has been released in the EU against an alien invasive weed. This dearth has occurred in the face of increasing numbers of exotic invasive plants being imported and taking over National Parks, forests and amenity areas in this region, as well as a global increase in the use of classical biological control around the world. This paper reviews potential European weed targets for classical biological control from ecological and socioeconomic perspectives using the criteria of historical biological control success, taxonomic isolation from European native flora, likely availability of biological control agents, invasiveness outside Europe and value to primary industry and horticulture (potential for conflicts of interest). We also review why classical biological control of European exotic plants remains untested, considering problems of funding and public perception. Finally, we consider the regulatory framework that surrounds such biological control activities within constituent countries of the EU to suggest how this approach may be adopted in the future for managing invasive exotic weeds in Europe.     

棉田黄萎病菌致病型结构初步研究

棉花黄萎病是棉花生产中的主要病害之一,广泛分布于世界各产棉国.控制该病的猖獗危害,已成为棉花生产可持续发展的主要问题[1].利用不同抗性的棉花品种对棉黄萎病菌的选择作用,从棉田中分离获得不同的黄萎病菌菌系,在温室中采用2个抗病性差异明显的品种对其致病力进行测定,以明确同一块棉田是否存在不同致病力菌系.     

Biological control of exotic pests in Italy: recent experiences and perspectives1

In Italy, successful application of classical biological control began in the 20th century, when Berlese released the predator Rodolia cardinalis in 1901 and the parasitoid Encarsia berlesei in 1906. Later, the ‘inoculative’ method was applied many times, limiting the misuse of insecticides and therefore achieving very positive effects for both the agricultural economy and environmental protection. When the establishment of new natural enemies failed, some exotic pests continued to damage important crops, sometimes disrupting any possibility of applying Integrated Pest Management (IPM). In other cases, new associations between exotic pests and native natural enemies occurred spontaneously and the importation of new species was not necessary: when no broad-spectrum plant protection products are applied, some palaearctic parasitoids, such as Diglyphus isaea, naturally control the imported American leafminers Liriomyza trifolii and L. huidobrensis and some native predators (mainly Orius spp.) often control the exotic western flower thrips Frankliniella occidentalis. However, the introduction of natural enemies from the area of origin of the exotic pest is often the only alternative to chemical insecticides. Since its introduction in 1979, the American Flatid, Metcalfa pruinosa, has been spreading annually into new areas of the Mediterranean, causing severe damage to many crops because none of the indigenous natural enemies are sufficiently effective. Therefore, only the introduction of exotic natural enemies, such as the parasitoid Neodryinus typhlocybae, may reduce the outbreaks.     

外来植物有害生物入侵及其对策

分析了外来植物有害生物传入我国蔓延危害的主要特点、发展态势及潜在风险.我国防范外来植物有害生物入侵,主要存在管理体制、法规制度、检疫手段和技术、人员素质和资金投入等诸方面问题.加强植物检疫职能、整合检疫管理力量、构建快速反应机制、确保安全服务贸易等是有效防范外来生物入侵的重要组织步骤;完善植物检疫立法和管理体制、重视技术标准研制和采用国际标准惯例、加快有害生物风险分析和重新确定检疫性有害生物名录、改进植物检疫检验手段和技术、加强非疫区和非疫生产基地建设、设立植物检疫专项基金、加强国际合作与交流等尤为迫切.     

林木害虫监测技术的研究进展

随着国际间贸易的频繁,外来林木害虫传入我国的风险加大,评估外来林木害虫扩散趋势和速度,建立有效的外来林木害虫监测系统显得尤为迫切。本文结合本课题组有关林木害虫诱集已取得的成果,综述了近年来国内外对外来林木害虫诱集监测技术的研究进展,并就建立适合我国的外来林木害虫监测体系提出建议。     

Exotic plants along roads near La Paz,Bolivia

Distributions of invasive alien species (IAS) are well documented all over the world, and roads are considered one of the main means by which IAS spread. Bolivia is one of a few countries for which there are no such studies. For this reason, we determined the number of exotic plant species in the vicinity of roads near the city of La Paz, Bolivia. We distinguish two types of roads, paved and gravel roads, and in their vicinity, we studied the floristic composition in three regions, differing mainly in altitude: high Andes, puna grassland and dry valley. We found three exotic species in the vicinity of roads in the high Andes, five in puna grassland and 10 in the dry valley. We found 13 exotic species along gravel roads and nine along paved roads, whilst there was a trend for such species to be more abundant close to the roads than further away. Pennisetum clandestinum was the most frequently recorded exotic species in all regions and associated with both types of roads. The results indicate that exotic species are quite frequent along roads in Bolivia and present a potential threat as invasive species. Therefore, it may be necessary to take measures to prevent IAS from spreading further.     

Global developments in biological control and the implications for Europe1

Developed and developing countries, for a range of reasons, have strongly endorsed an IPM approach to sustainable pest management. IPM is founded on the self-renewing contribution of natural enemies to pest suppression, or biological control. However, many pests today escape such natural control because they are exotic introductions, and for these pests the introduction of specific biological control agents is a proven and valuable technique. With growing exotic pest problems in agriculture and forestry, due both to increased trade and to the policy of the WTO, with new concern for exotic invasive species affecting biodiversity, and with a booming biocontrol industry, there is a rapid growth of interest in introduced biological control agents (including biopesticides, which are generally still not acknowledged as introductions). To meet this demand for biological control introductions, it is necessary to address issues of research, safety and the rights of governments and peoples to their genetic resources. By and large, Europe has not done this, and this is proving both an opportunity for environmental accidents and a disincentive for sustainable agriculture and conservation.     

Evaluating one century of classical biocontrol in Italy1

Introduction of pests into Italy appears to be increasing. Between 1974 and 1994, 82 exotic insect species have been recorded as new to Italy, representing approximately four introductions per year, compared with one species per year up to the 1960s and two species per year in the 1980s. To combat these, and native, pests, 28 entomophagous species have been used in the last 20 years in classical biological control programmes. At the same time, 24 other species of entomophages have played a role in pest control without human intervention (i.e. fortuitous associations). There are examples of native and introduced entomophages acting fortuitously or in planned programmes on native or introduced pests. So far, none of the introduced entomophages appear to have caused any negative effects on the Italian ecosystem. However, because of increasing concerns about the possibility of such effects, there is a need to develop clear protocols covering entry and release of biological control agents.