共查询到20条相似文献，搜索用时 31 毫秒
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Removing barriers to facilitate efficient water markets in the Murray-Darling Basin of Australia 总被引：1，自引：0，他引：1
M. Ejaz Qureshi Tian Shi Sumaira E. Qureshi Wendy Proctor 《Agricultural Water Management》2009,96(11):1641-1651
We discuss the role and characteristics of water markets in Australia in facilitating efficient water allocation. Administrative, regulatory and/or political barriers to effective functioning of water markets are reviewed with a focus on the southern Murray-Darling Basin (MDB) region of Australia. A mathematical model is developed to estimate the costs of existing restrictions and the benefits from potential changes in water markets (e.g., removing barriers in temporary water markets). The modelling results reveal that expanding trade leads to an increase in mean annual net returns from AU $2502 million to AU $2590 million (i.e., an increase of AU $88 million). When the current volume restrictions, exchange rates, and trading charges are accounted for, mean annual net returns reduced from AU $2590 million to AU $2573 million (i.e., a reduction of AU $17 million). The exclusion of any of the three southern MDB states from the interstate water trading imposes significant costs. If South Australia, New South Wales or Victoria withdraws from the water market, net returns are reduced by AU $27 million, AU $31 million and $63 million, respectively. The paper outlines the policy implications of strategies to remove market barriers and to facilitate efficient and effective water trading. 相似文献
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Tushaar Shah 《Agricultural Systems》1983,11(1):41-64
In a competitive agricultural commodity market, a parity can be expected between the prices of the raw materials and the prices of the final products. This paper attempts to show that such a parity does not exist between the price of liquid milk and the prices of milk fat and SNF in the forms in which they are produced in India, because the traditional milk producers do not have access to a technology that enables them to convert the SNF contained in their milk into products which have ready markets.This fact has given the modern dairy co-operatives of the rural milk producers a significant economic advantage in their competition with the traditional producers, since they have been able to give their members access to such a technology.This paper argues that the new, developing dairy co-operatives should devise their long-term strategies with a view to exploiting this economic advantage while it exists; for, in the long run, this advantage must disappear as competition among the dairy co-operatives in the markets for liquid milk and milk products increases. 相似文献
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Irrigation districts in Inner Mongolia face problems that are familiar to irrigation areas around the world: shortage of water resources, poor management of water, inefficient use of water resources, and imbalance of financial revenues and expenditures. Water user associations have been promoted to address water supply problems and to encourage efficient water use. In this study, farmers from three distinct areas in Inner Mongolia were surveyed to determine their level of understanding of water user associations and the factors that affect their becoming members. A majority of respondents thought that water user associations were useful to safeguard farmers’ interests, to help reduce labour inputs and disputes about water, to reduce irrigation costs, and to promote efficient water use. The factors found to be most important were: (1) being a village cadre; (2) good state of health; (3) high degree of understanding about water user associations; (4) small percentage of the household in the labour force; (5) cropping income a high percentage of family income; (6) having had previous conflicts involving water use issues. 相似文献
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G.J. Hoffman S.L. Rawlins J.D. Oster J.A. Jobes S.D. Merrill 《Agricultural Water Management》1979,2(3):177-192
Crop productivity and water use efficiency when saline irrigation water is used are highest when efficient irrigation systems are managed to meet the crop's leaching requirement. The objective of this experiment was to establish the leaching requirement. The objective of this experiment was to establish the leaching requirements for frequently irrigated wheat, grain sorghum, and head lettuce. The 4-year study in field plots consisted of six replicated leaching fraction treatments. The plots were pulse-irrigated daily with water having a total dissolved salts concentration of 1350 mg/l.The leaching requirements are 0.08 for wheat and sorghum, and 0.26 for lettuce. The respective evapotranspiration during each crop's growing season coincident with the leaching requirements was 440, 550, and 245 mm. A pan factor of 0.7 was consistent among these three crops at their respective leaching requirements. With daily irrigation, 90% of the crop's water uptake occurred above a soil depth of 0.6 m, independent of leaching fraction. 相似文献
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《Agricultural Systems》2005,86(2):207-222
Family composition and its changes over time are believed to have a major impact on the welfare and sustainability of small-scale, limited resource farm households. In order to understand and test the effects of household composition on overall farm household well-being, a simulation model was developed based on information from 60 small farms from the Coastal Cañete Valley, Peru. The model accounts dynamically for the birth, age and death of household members and for crop, livestock, and economic activities. A representative farm with ten scenarios representing the range of household composition was simulated. Results in 10, 20 and 40-year runs showed that family composition has a large influence on economic stress. Families with fewer members were economically better off after 10, 20, and even 40 years. With more young or very old members, the expenses and consumption requirements exceeded the benefits from the additional labor, and debt was greater and of longer duration. Changing prices and yields across their observed ranged of variability influenced simulated financial position, but not the ranking of results among household composition scenarios. 相似文献
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With the rewritten Article 27 of the Mexican Constitution and the National Water Law of 1992, Mexico embarked on an ambitious program of transferring the management of many irrigation systems to local user groups, primarily farmers. By 1996, 372 water user associations had been formed to control water delivery to 2.92 million hectares. During this time water prices increased by 45–180% and government O&M subsidies were eliminated. Limited economic analysis of stakeholder impact has been conducted of the irrigation management transfer (IMT) program. This research effort pilots a partial budget analytical framework for analyzing the social benefits and costs of IMT. Two irrigation modules near Culiacan, Sinaloa were selected as case studies. Results reveal that even with significantly higher water prices, water users have invested more in their systems than during the post-IMT period and consider their overall irrigation costs to be lower. Lower transaction costs in the pre-IMT period explain the majority of these cost savings. Efforts to quantify incremental benefits and costs associated with IMT at the module and district levels proved difficult given the unavailability of reliable, time series information. 相似文献
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生态效益价值评估对评价水土保持工程建设效果至关重要。对全国首个水土保持生态文明城市—洛阳市洛河水土保持工程生态效益进行价值评估,在建立生态河道水土保持工程生态效益评价指标体系的基础上,通过价格替代法、影子工程法等方法模型从安全价值、景观价值、气候价值、环境恢复价值四方面进行水土保持工程生态效益评估研究。研究表明,洛河水土保持措施的实施使得年均涵养水源量增加28.06万t,泥沙淤积量减少20.81万t,尘埃阻滞量9107t,土壤侵蚀量减少209.1万t。洛河水土保持措施生态效益年均总价值为11715.9万元,其中安全效益年均价值为7145.6万元、景观效益年均价值为1966.9万元、气候效益年均价值1504.9万元、环境恢复效益年均价值为1098.5万元。研究成果可为全国河流水土保持生态建设效益评价及生态文明城市建设提供参考。 相似文献
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高静 《中国农村水利水电》2010,(2):128-130
现行“471号令”中沿用的产值倍数法征地补偿费测试方法不适应我国大西南水电开发中的客观情况。从确立“公平补偿”为标准,保证移民福利水平不降低出发,进行移民搬迁前后的经济现金流分析,确定新的补偿技术路线,构造出收益法和成本法结合的补偿函数,提高了征地补偿测试方法的科学性和合理性,以期为我国的水电建设提供政策制定参考。 相似文献
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《Agricultural Systems》1998,57(3):381-398
Ways of ‘tracking’ environmental fluctuations could be of value in limiting drought-induced mortality and increasing output. We examined a range of tracking policies, designed to tackle climatic variation, using a simulation model of a semi-arid grazing system. These compared annual sales designed to limit stocking rate, pre-emptive sales triggered by insufficient rainfall, and variable sales and stocking rate regimes determined by the current season's rainfall. Although the flexible stocking strategies did reduce mortality losses, compared with fixed stocking, they did not increase average annual sales. The main reasons for this are that major losses of stock are associated less with 1-year than with 2-year droughts, which are difficult to track, and that destocking can be really effective only if the productive potential of the herd can be re-established more rapidly than is possible from depleted herd resources. Tracking policies did have a considerable advantage in terms of reduced inter-annual variability of sales, which would be of economic benefit to the commercial livestock sector. For subsistence pastoralists, the traditional policies of maintaining the maximum number of breeding stock, and of hoping that most of them will survive drought, may be as close as ‘opportunistic’ management can get to dealing with drought. 相似文献
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The physical assumptions and mathematical approximations leading to ten steady-state drainage equations for installations of parallel cylindrical drains laid above a horizontal impermeable barrier, are critically examined. Water-table heights were calculated from the equations for a range of depths of impermeable barrier and of rainfall rates, using the drain's radius obtained by the hodograph analysis for infinite depth of soil. A consideration of the available solutions show that the water-table height is known with sufficient accuracy for small depths of impermeable barrier and for large depths, but at intermediate depths the solutions lead to an unsatisfactorily large uncertainty in its position. Of the drainage equations Houghoudt's equivalent depth equation, when used with the optimum drain radius given by the hodograph analysis for infinite soil depth, is the only one that gives results contained mainly within the known bounds that result from a consideration of the combination of equations. 相似文献
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P.A. Okuneye 《Agricultural Systems》1985,18(4):195-206
In spite of the involvement of many research institutes and universities in arriving at suitable agricultural innovations and transferring these to farmers for adoption, agricultural productivity has remained low in Nigeria. The paper critically examines the extension methodology being adopted, which is particularly the Training and Visit approach using survey data obtained from farmer members and non-members of cooperative/group societies in some parts of southwest Nigeria. This approach has been found to be ineffective for a number of reasons. To achieve a rapid transfer and adoption of improved practices, a group approach involving demonstrating new technologies to farmers on their own farms is suggested. A continuous monitoring and evaluation unit can be developed in each area so as to improve on the previous year's performance and bring groups' comments to the notice and attention of researchers. 相似文献
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Biophysical and economic tradeoffs of intercropping timber with food crops in the Philippine uplands
《Agricultural Systems》2001,67(1):49-69
Steadily rising prices for timber on Mindanao in the Philippines have given an incentive to farmers to devote some of their land to fast-growing tree species. The costs and benefits of intercropping young timber trees with food crops was studied in a 1000 stem ha−1 stand of Paraserianthes falcataria. At 2 years of age, diameter at breast height and height of intercropped trees were 33 and 21% greater, respectively, than sole trees. Management costs of intercropped trees were less than half of sole trees. Allometric equations for Mindanao falcataria were used to project future tree growth and system returns. In the base scenario (1000 trees ha−1, 5-year rotation), the sum of biophysical and economic benefits of intercropping trees with a maize/vegetable rotation for two years were less than the costs of reduced intercrop yield, compared to sole cropping of each component. A linear relationship of crop decline to the increase in basal area of the stand was used to predict returns to intercropping under alternative tree densities and intercropping periods. Intercropping becomes more attractive as labor becomes scarcer relative to land, the need to minimize cash inputs becomes more important to farmers, and trees increase in value relative to annual crops. 相似文献
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A simulation model is presented for a typical Australian pome fruit orchard. The main routine calculates annual after-tax profit and sub routines generate optimum replacement age and stochastic variability due to hail and drought. The principal dependent variables such as prices, yields and costs can be changed as required to add flexibility for various practical circumtances. Two replacement policies are used, self replacement (270 trees/ha) and semi-intensive (715 trees/ha). Under mean price and yield conditions, converting the orchard to semi-intensive production gives an average annual improvement in profit of $13 000 over a 100 year simulation period. Results emphasised the need for earlier replacement of trees than is usual practice. Existing trees were replaced at 31 years of age and thereafter recycled at 46 year intervals. Application of regression analysis to produce iso-performance curves revealed important interactions between price, cost, yield and orchard profitability with price being the most sensitive parameter. 相似文献
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This paper presents a statistical analysis of the UK's food supplies in order to indicate the size of the problem of food losses and therefore to illustrate the potential savings.The energy and protein value of the food leaving UK farms and ports for consumption in the UK is estimated to be: Energy: 385 J × 105 per annum Protein: 3·2 million tonnes per annum By comparison the energy and protein needs of the entire UK population are: Energy: 200 J × 1015 per annum Protein: 1·2 million tonnes per annumThe UK food system is losing a considerable proportion of the food material which is available for consumption in the UK. Much of this loss occurs during the primary processing prior to the food ‘moving into consumption’. The loss at this stage amounts to: Energy: 116 J × 1015 per annum Protein: 1·5 million tonnes per annumThe authors discuss the implications of this loss of efficiency and give generalised reasons for its occurrence. 相似文献
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Michael Halse 《Agricultural Systems》1979,4(4):239-278
The purpose of the work reported in this paper was to analyse the relevance of the concept of conversion efficiency to India's agriculture, in general, and to India's dairying, in particular.On the basis of this work, the main conclusions were: The concept of conversion efficiency can be useful to decision-makers in India's agriculture sector; however, when using the concept, care has to be taken to differentiate between inputs which are scarce and inputs which are in free supply, such as crop residues and natural herbage. Dairy production in India is based on the use of crop residues and natural herbage; for this reason, such scarce inputs as are used in India's dairy production are used efficiently, and there need be no conflict between the production of milk in India and the production of other foods needed for an adequate national diet. 相似文献
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Cengiz Ko? 《Irrigation and Drainage Systems》2011,25(4):255-263
The cost constructing for irrigation is often given in $/ha. In deciding whether a project is worth undertaking, it is important to weigh the anticipated benefits against the expected costs. In this study, unit area construction costs based on the way of project water supply (gravity, pump) and scheme type (classic canal, flume, pipe) were calculated for the 211 irrigation projects operated and constructed by DSI (State Hydraulic Works) in Turkey. In a case study of the 27 irrigation schemes constructed by DSI in the Büyük Menderes and West Mediterranean basins, construction costs per unit area, irrigation ratio, and amount of unproductive costs were determined. As a result, though the area of 76383 ha was constructed for irrigation schemes, this area wasn??t under irrigation services with several various reasons; therefore, 641 million $US according to water supply way, and 574 million $US to the scheme type were unproductive investment for irrigation projects researched in the basins. 相似文献
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人民胜利渠灌区多水源循环转化模型研究 总被引：2，自引：0，他引：2
从取水、输水、配水、排水系统的角度,构建了人民胜利渠灌区多水源循环转化模型,定量模拟分析了人民胜利渠灌区系统多年平均下的多水源循环转化关系。结果表明,从农田灌排系统角度,构建灌区多水源循环转化模型是可行的,能够较好地模拟灌区系统多水源循环转化过程;人民胜利渠灌区水资源的转化主要集中在输水和配水系统中,水资源转化量分别约为1.76亿和9.66亿m~3,取水系统和排水系统水资源转化量较小,分别为0.01亿和0.13亿m~3。输水系统中水资源转化以渗漏为主,渠系渗漏量约占总引黄水量的44%,这增加了引黄输水渠道沿线农田遭受渍害和土壤次生盐碱化的风险;配水系统中农田渗漏量约占水资源转化量的28%,这可能与部分地区仍采用落后的灌溉方式有关。 相似文献