The economics of sutchi catfish (Pangasianodon hypophthalmus) aquaculture under three different farming systems in rural Bangladesh

This paper examines production costs and returns of sutchi catfish (Pangasianodon hypophthalmus) aquaculture under three different farming systems in Bangladesh. Based on the production technology, sutchi catfish farming is classified as extensive, semi‐intensive and intensive. Results showed that sutchi catfish farming is profitable irrespective of the level of intensification and in all three instances the cost of feed dominated the variable costs of production. The average annual production costs were estimated at US$5217 ha^?1 in intensive farming, while US$2694 ha^?1 in semi‐intensive and US$981 ha^?1 in extensive farming. Despite the higher production costs per hectare, the average annual net return was higher in intensive farming (US$3364), compared with semi‐intensive (US$2048) and extensive (US$1099) farming. The average annual production per hectare under intensive farming conditions (13 945 kg) was higher than semi‐intensive (7705 kg) and extensive (3380 kg) farming mainly due to higher levels of inputs, including seed, feed, fertilizer and labour. However, the Cobb–Douglas production function model suggests that inputs are inefficiently used in the intensive farming system. Conversely, there is enough scope to increase the production and income from the semi‐intensive and extensive farming systems by using more inputs.     

小城镇产业发展战略分析

科学的产业政策是小城镇发展的决定因素。为此,结合我国小城镇实际,总结出小城镇产业调整与优化的原则;提出了小城镇产业发展的总体思路;并在详细地分析鸦鸿桥镇产业特点的基础上,提出了该镇“工贸型”产业发展战略,以及以强化市场建设为中心的产业发展措施。     

The Michigan equine monitoring system. I. Design, implementation and population estimates

The Michigan equine monitoring system (MEMS) was designed and implemented in the State of Michigan, starting in 1991. The program was designed systematically to track the State's equine population, its health, and its economic implications to the equine industry. The MEMS was designed as a two-phase program. Phase I (the population and economic survey; the subject of this paper) was designed to provide new and statistically valid information describing the size, composition, location and economic characteristics of the Michigan equine industry. A standardized questionnaire was used to collect data via mail, telephone and personal interviews.

Of the 3000 randomly selected list-frame samples, 2800 (93%) participated. However, 650 of these had no equids. There were 129932 equids reported compared with 160000 in 1984. The American Quarter Horse, Standardbred and Arabian breeds were the most numerous. Detailed results, including the size of equine operations/herds, uses, geographical distribution and the financial structure of the industry, are presented. A detailed account of the strategies used in designing and implementing the system is provided.     

Agricultural policy and social returns to eradication programs: the case of Aujeszky''s disease in Sweden

Economic-welfare analysis of animal disease prevention programs frequently ignore the constraints of the agricultural policy environment. Prevention programs affect producers, consumers and the government. The policy environment to a large extent determines the magnitude as well as the distribution of benefits of the program among these groups. The Swedish hog industry has been exposed to three major policy changes during the 1990–1995 period. These scenarios involve various degrees of government intervention in the agricultural sector including internal market deregulation and EU-membership. Aujeszky's disease is a virus disease with swine as the natural infection reservoir. Piglets are the most fragile and an outbreak of the disease results in symptoms such as shaking, cramps and convulsions with an increase in the mortality rate. Slaughter hogs suffer from coughing, fever and reduce their feed consumption. During the last 20–25 years the incidence of Aujeszky's disease (AD) has been increasing in Sweden. In 1989 an eradication program was undertaken. A model is developed to analyze social benefits of an eradication program given variations in agricultural policy. The model refers to the specifics of the AD-program implemented in Sweden. The expected benefits of the program are evaluated using a welfare-economic analysis applying cost-benefit analysis. Total benefits of the program are evaluated across herd and size categories and different regions. Data concerning the frequency of the virus among various categories of herds prior to enacting the program were used (Wahlström et al., 1990). In addition, data from an agricultural insurance company were used to estimate the conditional probability of an outbreak given that the herd is infected. Biological and technical parameter values were collected from a variety of sources. The results of the analysis indicate that the program is economically viable given a social rate of discount in the range of 3–5% without considering non-monetary aspects such as animal ethics. A scenario where the Swedish agricultural sector is deregulated provides the maximum benefits of the program. Consumers obtain about 50% of the benefits excluding program costs. The deregulation scenario would correspond closely to a case where a reformed Common Agricultural Policy (CAP) is applied across member countries. In the current case where Sweden is a member of the EU, the benefits are reduced mainly due to lower prices of inputs and pork.     

胡庶华--杰出的工程、经济科学管理先驱者

以新发现的史料,从管理科学与工程的视角,对近代三任湖南大学校长胡庶华(1886～1968)在中国管理现代化历程中的先驱活动进行了探讨和述评.     

Model of wheat yield response to application of diclofop-methyl to control ryegrass (Lolium rigidum)

A general model of crop yield response to herbicide application is proposed. The model includes three components: the effect of herbicide dosage on weed density, the effect of surviving weed density on crop yield and the effect of herbicide directly on the crop. The model is used to estimate the response of wheat yield to application of diclofop-methyl to control ryegrass (Lolium rigidum) in Australia. It is found that the competitiveness of ryegrass plants surviving treatment is reduced by the treatment and that the proportion of yield loss at a given ryegrass density is not independent of the absolute weed-free yield. The response function is used to calculate economic thresholds and optimal herbicide dosages.     

浅议精细农业中的环境经济效益

通过肥料效用函数等方法来阐释精确施肥技术所造成的生态环境和经济效益之间的关系。     

我国农民收入不平衡状况分析

我国农民收入的不平衡问题表现形式比较多,原因也各不相同。解决我国农民收入不平衡问题的对策主要有提高农民的文化素质、调整农业结构以及加大中央政府的转移支付力度。     

收益还原法评估农用地价格中客观总费用的确定

收益还原法是评估农用地价格的主要方法之一。作为该方法中最重要的参数之一，客观纯收益的确定往往依赖于农业客观总收入扣除客观总费用。为此，结合具体农业生产实践活动和所从事的农地估价实践活动，详细分析了农业生产活动中可能发生的费用，并尝试分析了各种费用的确定方法，以期对具体的估价实践有一定的指导意义。     

技术进步与经济可持续发展的关系

经济要保持可持续性的发展，就必需以技术进步作为主要手段。在科学技术飞速发展的今天，技术进步已成为经济增长的主要推动力和决定性因素。为此，阐述了技术进步与经济可持续发展的关系，探讨了技术进步对经济可持续发展的促进作用。