农村投融资制度变迁的经济效应     

罗春玲  温涛 《四川畜牧兽医学院学报》2008,(3):38-42

我国现有农村投融资的糊度性缺陷已成为糊约解决“三农”问题的瓶颈，不适应农业和农村经济发展的需要。文中以翩度经济学为理论依据，分析了农村投融资制度演进的特征，并对其制度变迁的经济效应进行了理论和实证分析。  相似文献   

An Economic Investigation of Early-Generation Quality Testing in a Wheat Breeding Program     

J. P. Brennan  L. O'Brien 《Plant Breeding》1991,106(2):132-140

Public plant breeders, in seeking the most efficient means of achieving their objectives, face decisions on the appropriate breeding strategy and program structure to use. This paper reports an analysis comparing the changes in costs and benefits from the introduction of recent technology enabling testing for flour and dough properties to be carried out on small samples in the early-generations of a wheat breeding program in Australia. The average costs of a suite of early-generation tests are higher than the equivalent (unreplicated) yield testing. The analysis presented confirms that the introduction of early-generation quality testing leads to a faster rate of expected progress in quality, but a slower rate of progress in yield. The estimated market value of an increase in yield is greater than that for quality, based on current market information. Thus, the result of incorporating early-generation quality testing is higher costs and lower expected returns, so that there is a loss of community welfare from using early-generation quality testing if the resultant cultivar is released from each program. However, the probability of the higher-quality cultivar being released for commercial cultivation is greater, so that recognition of the probability of release means that there may be net gains from the use of early-generation quality testing.  相似文献   

Reduced Milk Production in Udder Quarters with Subclinical Mastitis and Associated Economic Losses in Crossbred Dairy Cows in Ethiopia   总被引：2，自引：1，他引：1  

Mungube EO  Tenhagen BA  Regassa F  Kyule MN  Shiferaw Y  Kassa T  Baumann MP 《Tropical animal health and production》2005,37(6):503-512

The objective of the study was to estimate the losses associated with subclinical mastitis (SCM) in crossbred dairy cows in the Central Highlands of Ethiopia. A split udder investigation was performed with 30 cows to determine production losses associated with SCM. Each quarter of the study cows was examined using the California Mastitis Test (CMT) and quarter milk production was measured over a period of 8 days. Production losses were determined for different CMT scores by comparing production of quarters with CMT score 0 to quarters with CMT scores trace, 1, 2 and 3, respectively. Using data from a recently published study, economic losses were determined for different farm sizes and production subsystems by multiplying the prevalence of the respective CMT scores with the production losses associated with these CMT scores. Mean quarter milk production was 0.82 + 0.40 kg per milking in the split udder trial. Milk production was reduced by 1.2%, 6.3%, and 33% in quarters with CMT scores 1+, 2+, and 3+, respectively. Using data from the published study, a quarter with SCM lost an average of 17.2% of its milk production. Production losses associated with SCM were estimated at 5.6% for the Addis Ababa Milk Shed. Stratified losses were highest (9.3%) in urban dairy farms (UDF) and small-scale farms (6.3%). The estimates of the financial losses ranged from US$29.1 in dairy herds in secondary towns (DHIST) to US$66.6 in UDF. A total loss of US$38 was estimated for each cow per lactation. Reducing mastitis in UDF (highest prevalence) to the level of DHIST (lowest prevalence) could reduce the loss by US$35. As this does not include costs associated with treatment or culling of diseased cows, this figure probably underestimates the possible benefits of control measures.  相似文献   

图书情报领域信息经济学研究的文献计量分析     

陈新红  孙雅欣  胡艳君 《农业环境科学学报》2012,31(6)

利用CNKI知识平台上的CSSCI期刊,对图书情报领域信息经济学相关的576篇文献的年代分布、著者分布、期刊分布、机构分布、基金分布、关键词分布等文献计量分析,以揭示该领域的研究现状。  相似文献   

多层次防护林体系生态服务价值评价方法   总被引：1，自引：0，他引：1  

陆志家  王让会 《广东农业科学》2012,39(1):142-146

利用对和田地区多层次防护林区的调查研究,进行了林区生态服务功能价值的估算。评估结果表明,在和田玉北的多层次防护林体系中,生态服务价值居第一位的是生物多样性保护,总价值为2.12×106元,占总比例的43.09%;位居第二位的是净化大气环境,价值1.08×106元,占总比例的21.95%;调节大气组分价值排在第三位,为19.35%;涵养水源价值占总比例的11.85%,固土保肥价值量最小,仅占3.76%;在不同的治沙工程措施中,与天然稀疏植被封育区、草方格固沙-人工林区和人工林区相比,多种植物配置区土壤肥力较高,单位面积的价值最高,达到了266.67元/hm2。  相似文献   

我国西部农村发展的内源性跨越新解——基于回乡“创业经济”的另类思维     

李华红 《农业现代化研究》2012,33(6):651-655

做大做强农民工回乡"创业经济"是劳务经济发展的本源,它对西部农村社会发展能起到"治本"作用,即有助于西部农村经济、社会、人与自然关系的协调发展,以及西部"人"自身全面发展。调查发现,西部地区农民工返乡创业中面临着缺资金、缺项目、缺环境、缺信息等难题,且在创业实践中还存在倾向"单干"、模仿跟风、依赖思想、规模小、技术化程度不高、资源型创业等特殊性现象需重视。解决这些问题亟需完善相关体制机制,主要是对返乡农民工予以立体式创业培训,加大金融支持,强化政策扶持,加强创业组织建设等。  相似文献   

Criteria and guidance considerations for sustainable tree stump harvesting in British Columbia     

《Scandinavian Journal of Forest Research》2012,27(8):709-723

Abstract

Stump extraction for forest health has been carried out operationally in British Columbia (BC) for many years. Emerging bioenergy opportunities plus the anticipated need for more fibre because of reductions in timber supply may increase interest in stump harvesting, but there are numerous environmental, economic and policy barriers that must be overcome first before industrial-scale stump harvesting can be seriously considered in BC. The potential for a future change in practice provides an opportunity to learn from the existing literature and identify knowledge gaps. In this article we review the available literature on stump harvesting from the European Union within the context of BC's forests, economy, biodiversity, environment and policies. We provide recommendations on how the government of BC could move forward if they decide to enable stump harvesting for fibre and bioenergy, including assessment of net economic and carbon benefits and environmental effects, improvements in inventory and the scientific knowledge base needed to support policy and guidance, and investigation of operational enhancements.  相似文献   

Exploring the silvicultural and economic viability of gap cutting in Mediterranean softwood plantations     

Roberto MERCURIO  Raffaele SPINELLI 《中国林学(英文版)》2012,14(1):63-69

Gap cutting consists of the removal of all trees growing on a small surface,varying in size from 200 to 600 m 2.In Italy,gap cutting has been successfully tested for introducing the natural regeneration of native species into softwood plantations,thus accelerating the transition towards climax hardwood stands.Depending on plantation types and conditions,gap cutting should be started at an age between 70 and 80 years and the system should include at least 12 to 15 gaps,in order to produce enough wood to cover costs.Generally,natural regeneration is firmly established within 5-7 years from treatment.Gap cutting also offers superior results to selection thinning,the latter producing about 35% less value and incurring 25% to 30% more costs.As for all regeneration cuts,the success of gap cutting depends on wildlife control in order to prevent extensive damage to the regeneration.  相似文献   

An Assessment of Forest Policy Changes in Western Washington     

《Journal of Sustainable Forestry》2013,32(4):63-94

Abstract

Changing forest policies in both riparian and upland areas to help protect threatened and endangered species have contributed to the reduction of timber harvests in western Washington. The economic, biodiversity, and environmental impacts of these policy actions have been substantial. Policy simulations across 9.4 million acres of timber-land show that relative to proactive management strategies, current habitat conservation and environmental programs (largely based on a reservation strategy) result in net present value reductions to forestland owners of $9.9 billion. Accompanying these asset value reductions are employment losses (sustained) of 30% and tax receipt losses of 26%. The policy simulations further demonstrate that proactive management will not decrease the long-term percentage of the upland landscape occupied by functionally old forests relative to the reservation strategy. In the riparian area, adoption of a reservation strategy actually decreases (by 29%) the percent of the landscape occupied by functionally old forests relative to a proactive management approach. These results illustrate the importance of proactively managing western Washington forests to provide maximum functionally old forest habitat for endangered upland animals (such as the northern spotted owl and the marbled murrelet) as well as riparian species.  相似文献   

消费者对转基因食品的消费偏好研究     

刘玉芹 《安徽农业科学》2013,(31):12450-12451

转基因食品自问世以来在各个国家都饱受争议。消费者对转基因食品的消费偏好是转基因食品推广的基础。在前人的研究基础上,采用实地实验的方法来研究消费者的消费偏好。同时,在实地实验中加入风险偏好的测量实验,研究消费者的风险偏好对转基因食品消费偏好的影响。研究结果表明,消费者对转基因食品的消费偏好有明显的下降,风险偏好程度对转基因食品的消费态度并没有显著的影响。  相似文献