首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Cotton is one of the most important crops in West Africa and is a major catalyst of economic development in rural areas, but the sector has suffered from a decline in the world cotton price after 1999. This article exploits an unusual data set following 82 farmers over 14 years, from 1994 through 2007, to estimate a Nerlovian supply response model for cotton, maize, sorghum, and millet in long-term rotation. The resulting system of equations is estimated with two-stage least squares (2SLS), showing that this sample of Malian cotton producers have responded to prices in a relatively inelastic manner, with supply elasticities only about one-half of those estimated for producers in developed countries. Policy reforms could help producers respond more easily to prices changes, as well as to raise average productivity levels.  相似文献   

2.
3.
Investments in agricultural research and development (R&D) made over the next few decades will likely prove critical in offsetting adverse climate change impacts on the global food system. In this study, we offer cost estimates of public R&D-led adaptation to climate change grounded in an explicit framework relating the flow of annual R&D expenditures to building knowledge capital and thereby raising productivity in agriculture. Our research uses a comprehensive collection of historical public agricultural R&D expenditure and a literature review of elasticity estimates linking knowledge stocks to agricultural productivity growth for key world regions. Given climate-driven crop yield projections generated from extreme combinations of crop and global circulation models, we find that offsetting crop yield losses projected by climate and crop models over 2006–2050 would require increased R&D adaptation investments of between $187 billion and $1,384 billion (in 2005 $PPP) if we invest between 2020 and 2040. This is 16–118% higher than global R&D investment if present spending trends continue. Although these costs are significant, worldwide R&D-led climate adaptation could offer favorable economic returns. Moreover, R&D-led adaptation could deliver gains in food security and environmental sustainability by mitigating food price increases and slowing cropland expansion.  相似文献   

4.
Soil fertility decline and soil management for crop production are important economic issues for grain growers in north-eastern Australia. In that region, there is evidence of soil fertility decline which is attributed to past crop management practices. The questions addressed in this article are first, whether components of soil fertility can be improved by better management and second, by how much soil fertility would change. Soil fertility for crop production is considered in terms of soil organic carbon and nitrogen. A stochastic dynamic economic analysis of soil fertility management for wheat production is presented. A sequential analysis of first deriving the optimal nitrogen stock and application rates is followed by an assessment of tillage, stubble, and fertilizer strategies to obtain an optimal level of soil organic carbon. The recommended management practices are consistent with emerging management trends in the region. The derivation of optimal levels of soil fertility for agricultural purposes has other policy implications, which we discuss.  相似文献   

5.
Extension programs to encourage farmers to reduce reliance on herbicides by adopting integrated weed management (IWM) practices have met with limited success. Studies aiming to understand the factors that influence farmers' choices of integrated control practices have faced difficulties in variable specification, and have not achieved high explanatory power. Using data from grain growers in Western Australia, where herbicide resistance in major crop weeds is common, this study tests the applicability of a framework for the IWM adoption decision in which herbicide efficacy is assumed to be a potentially exhaustible resource. Farmers' perceptions of multiple techniques and other variables are aggregated using principal components, and used in logistic regressions to explain the intensity of use of IWM practices. Eighty‐six percent of growers were correctly classified according to use of multiple IWM practices. Herbicide resistance and expectations of the future availability of effective new herbicides were significant in explaining IWM adoption. IWM adoption and herbicide‐resistance management are shown to be information‐intensive and involving an intertemporal resource management decision.  相似文献   

6.
We analyze sources of information in agricultural markets to understand patterns of demand for decision support services and the division of labor in the supply of these services. Information formatting—qualitative variation that determines accessibility and relevance of information in specific contexts—prohibits universal access to informational content. Information formats give rise to both transaction costs and complementarities reflected in patterns of information exchange in commodity systems. Controlling for actors' structural roles and levels of education, we develop a hedonic model of information demand such that actors seek information that is formatted to meet their needs and capabilities. Employing survey data, we explain elements of observed patterns of information exchange in four commodity systems in the USA. Results point to opportunities to expand our understanding of socioeconomic processes underlying production and consumption of decision support.  相似文献   

7.
Although recurrent evidence is found that consumers have different willingness to pay for GM and non-GM products, there is disagreement in the scientific community about the size of consumer benefits from GM labeling. In this article we use a theoretical model based on a standard constant elasticity of substitution (CES) to explain the importance of the quality effect. It is shown that failing to consider the quality effect may yield an overestimation of benefits from GM labeling, voluntary or mandatory.  相似文献   

8.
This article analyzes the effect of production uncertainty on farmland allocation decisions between perennial and annual crops, focusing on a representative farmer's attitude toward risk. A dynamic stochastic optimization model that considers net planting—the difference between new plantings and removals of perennial crops that achieve full production cycle—is used. The effect of uncertainty on the representative farmer's decisions to increase or decrease perennial crops’ acreage, on the optimal path, is examined. Our results reveal that the response of optimal path of net planting to uncertainty related to perennial crop production is highly affected by the farmer's attitude toward risk. A risk‐averse or a low‐risk loving farmer tends to reduce land allocation to perennial crops under uncertainty, while a high‐risk loving farmer will do exactly the opposite. Also, due to disutility of farming, the farmer tends to reduce land allocation to perennial crops when prices are high enough for him to attain a desired income level expectation. One implication of this research is the need for mechanization—in sub‐Saharan countries in particular—that increases per‐acreage yield and output in semisubsistence agriculture.  相似文献   

9.
Although adoption rates of genetically modified crops have been staggering in some countries, there is still comparatively little evidence about biotechnology impacts under diverse agroecological and institutional conditions. These knowledge gaps lead to an overly precautious attitude among policy makers and the public. This article analyzes the effects of Roundup Ready (RR) soybeans in Argentina, the country with the second biggest transgenic area worldwide. Based on recent survey data, it is shown that the technology increases total factor productivity by 10% on average, with cost savings being somewhat more pronounced for smaller than for larger farms. The reduction in use of toxic herbicides and of tillage operations entails positive environmental repercussions. Aggregate welfare effects are computed over the 1996–2001 period with a three-region, partial equilibrium model, comprising Argentina, the United States, and the rest of the world. In 2001, RR soybeans created more than US$1.2 billion of economic surplus at the global level. The largest share went to consumers (53%), followed by seed and biotechnology firms (34%), and agricultural producers (13%). Due to comparatively weak intellectual property protection, and thus only small technology mark-ups in seed prices and widespread adoption, Argentine soybean growers receive 90% of the benefits in that country. This demonstrates that farmers in developing countries can gain considerably when they obtain access to suitable foreign innovations through technology spill-overs.  相似文献   

10.
Consumer preferences for cowpea in Cameroon and Ghana   总被引:1,自引:0,他引:1  
Consumer preference information is essential to targeting research. This paper reports an effort of a multi‐disciplinary team to measure the market value of cowpea characteristics. Five samples were purchased once per month in seven markets in Ghana and Cameroon starting in September 1996. In the market, price and vendor characteristics were noted. In the laboratory, size of grains, testa color, testa texture, eye color and damage levels were recorded. A hedonic pricing regression model was used. Results indicate that grain size is the most important characteristic. Consumers seem more sensitive to bruchid (Callosobruchus maculates) damage than hypothesized. Cowpeas with white testa command a clear premium only in one of the Ghanaian markets. In Ghana, black eyes sell at a premium, but in Cameroon black eyes are discounted. In general, this study indicates that quality characteristics are very important in West African food markets. Even low income consumers are willing to pay a premium for products that match their preferences, and they are vigilant in identifying products that do not meet their standards. Purchasing samples on a regular basis and hedonic pricing offers a practical way for biological scientists and economists to work together to measure these consumer preferences.  相似文献   

11.
This article develops a framework to examine the ex ante benefits of transgenic research on drought in eight low-income countries, including the benefits to producers and consumers from farm income stabilization and the potential magnitude of private sector profits from intellectual property rights (IPRs). The framework employs country-specific agroecological–drought risk zones and considers both yield increases and yield variance reductions when estimating producer and consumer benefits from research. Benefits from yield variance reductions are shown to be an important component of aggregate drought research benefits, representing 40% of total benefits across the eight countries. Further, estimated annual benefits of US$178 million to the private sector suggest that significant incentives exist for participation in transgenic drought tolerance research.  相似文献   

12.
This study evaluates the impact of a long‐term research collaboration between the Senegalese Institute for Agriculture Research (ISRA), and the Bean/Cowpea Collaborative Research Support Program (CRSP) funded by the U.S. Agency for International Development (USAID). Adoption of the primary outputs from this collaboration, a nonchemical cowpea storage method and two short‐season cowpea varieties, were tracked through a series of farmer interviews in 1996, 1997, and 2004 in the main cowpea growing area of Senegal. Combined with information from an impact assessment in the late 1980s, this study draws on ex‐post adoption data from most of the product life cycle for the storage technology. The 2004 survey found that 60.4% of cowpea production in the main cowpea growing area of Senegal is stored in metal drums and that 69% of households use this storage technology; ISRA/CRSP improved short season varieties were determined to account for 3.6% of cowpea production. Baseline economic analysis of the most recent survey data, which includes benefits and costs of the storage technology and improved varieties, reveal an IRR to donor funding of 13%. The benefits of these technologies appear to be evenly distributed in the rural population on the basis of gender and ethnic background. Comparison of the rates of technology adoption over time, however, reveals that use of the storage technology may be decreasing; inclusion of this technology disadoption trend reduces the IRR by only 0.4% from the baseline estimate. Overall, estimated returns reveal that this collaboration has been a good investment for the U.S. and Senegalese governments, and other donors.  相似文献   

13.
Estimating a Primal Model of Regional Crop Supply in the European Union   总被引:1,自引:0,他引:1  
This article estimates behavioural parameters of the quadratic regional supply models in the modelling system CAPRI. Using the time‐series data in the CAPRI database, we directly estimate the optimality conditions using a Bayesian highest posterior density estimator. After discarding regions with insufficient data, parameters for up to 23 crop production activities with related inputs, outputs, prices and behavioural functions are estimated for 219 regions in EU‐27. The results are systematically compared with the outcomes of other studies. For crop aggregates (e.g. cereals, oilseeds, etc.) at the national level, the estimated own price elasticities of supply are found to be in a plausible range. On a regional level and for individual crops, the picture is much more diverse. As far as we know, there is no other study of similar regional and product coverage.  相似文献   

14.
Declining agricultural incomes, increasing concern over rural poverty and sporadic crises such as those of Bovine Spongiform Encephalopathy (BSE) and Foot and Mouth Disease mean that the imposition of further costs on U.K. agriculture are likely to be politically and socially sensitive. Such additional costs are however on the agenda with the implementation of the Water Framework Directive (WFD; European Commission, 2000 ). The WFD aims to achieve “good ecological status” in EU water bodies reducing, inter alia, diffuse pollution from agriculture. In this study, we assess four possible WFD measures proposed to the U.K. Department for Environment, Food, and Rural Affairs: reducing inorganic fertilizer application, conversion of arable land to ungrazed grassland, reducing livestock stocking rates, and reducing livestock dietary N and P intakes. For each measure, changes in farm gross margins (FGMs) are estimated using a dataset of over 2000 farms. In contrast to previous analyses, which have focussed upon mean responses on stylized farms, our approach allows the analysis of the range of impacts across a wide variety of real‐world farms and farm types. Findings reveal high variability in impacts. Cost‐effectiveness analysis indicates that, on average, cropping farms seem capable of reducing nutrient leaching in a more cost‐efficient way than livestock or dairy enterprises.  相似文献   

15.
Biofuels often raise the specter of food insecurity, water resource depletion, and greenhouse gas emissions from land clearing. These concerns underpin the “sustainability criteria” governing access to European biofuel markets. However, it is unclear if producing biofuels in low‐income countries does exacerbate poverty and food insecurity, and moreover, whether the sustainability criteria should apply to all agricultural exports entering European markets. We develop an integrated modeling framework to simultaneously assess the economic and environmental impacts of producing biofuels in Malawi. We incorporate the effects of land use change on crop water use, and the opportunity costs of using scarce resources for biofuels instead of other crops. We find that biofuel production reduces poverty and food insecurity by raising household incomes. Irrigated outgrower schemes, rather than estate farms, lead to better economic outcomes, fewer emissions, and similar water requirements. Nevertheless, to gain access to European markets, Malawi would need to reduce emissions from ethanol plants. We find that biofuels’ economic and emissions outcomes are generally preferable to tobacco or soybeans. We conclude that the sustainability criteria encourage more sustainable biofuel production in countries like Malawi, but are perhaps overly biased against biofuels since other export crops raise similar concerns about food security and environmental impacts.  相似文献   

16.
This article investigates the link between financing and investment in Ukrainian agriculture during economic transition. The main contribution of the study is to provide empirical evidence for the coexistence of financial constraints and soft budget constraints (SBCs). This is of particular importance because credit constraints and SBCs have completely different economic effects. The lack of differentiation between these forms of capital market imperfections yields overlapping effects of financing on investment and may therefore cause a misinterpretation of econometric results. Our empirical analyses are based on an econometric estimation of the Euler investment equations for 529 large farms from three Ukrainian regions between 2001 and 2005. The results confirm that financial variables significantly influence farms' investment, providing empirical evidence of an imperfect capital market in Ukrainian agriculture. It turns out that credit constraints in the Ukrainian agricultural sector are more important than SBCs. We show that the estimated level of financial constraints for profitable farms with access to loans is higher if both types of capital market imperfections are appropriately distinguished.  相似文献   

17.
This article assembles the results of three multicountry surveys on variety performance and adoption patterns to measure the impacts of maize research in West and Central Africa from 1981 to 2005, and uses cost data since 1971 to compute social rates of return on public investments in maize research in the region. Adoption of modern varieties increased from less than 5% of the maize area in the 1970s to about 60% in 2005, yielding an aggregate rate of return on research and development (R&D) investment of 43%. The estimated number of people moved out of poverty through adoption of new maize varieties rose gradually in the 1980s to more than one million people per year since the mid 1990s. Over half of these impacts can be attributed to international maize research at IITA and CIMMYT. The article concludes with a discussion of strategic options to enhance the impacts of maize research in the region.  相似文献   

18.
19.
Integrated Assessment studies have shown that meeting ambitious greenhouse gas mitigation targets will require substantial amounts of bioenergy as part of the future energy mix. In the course of the Agricultural Model Intercomparison and Improvement Project (AgMIP), five global agro‐economic models were used to analyze a future scenario with global demand for ligno‐cellulosic bioenergy rising to about 100 ExaJoule in 2050. From this exercise a tentative conclusion can be drawn that ambitious climate change mitigation need not drive up global food prices much, if the extra land required for bioenergy production is accessible or if the feedstock, for example, from forests, does not directly compete for agricultural land. Agricultural price effects across models by the year 2050 from high bioenergy demand in an ambitious mitigation scenario appear to be much smaller (+5% average across models) than from direct climate impacts on crop yields in a high‐emission scenario (+25% average across models). However, potential future scarcities of water and nutrients, policy‐induced restrictions on agricultural land expansion, as well as potential welfare losses have not been specifically looked at in this exercise.  相似文献   

20.
An examination of the economic impacts of Bovine‐Leukosis virus indicated that reduced milk production, attributed to the presence of Bovine‐Leukosis virus in dairy cows, reduced consumer surplus by 2.7 ± 2.3 billion US$ (bUS$), and resulted in a total partial equilibrium loss of 720 ± 560 million US$ (mUS$) to the U.S. economy in 1996. Most of the economic surplus lost by consumers was transferred to producers, whose economic surplus increased by 2.0 ± 1.8 bUS$ as a result of reduced milk production attributed to the presence of Bovine‐Leukosis virus in dairy cattle. Uncertainty analysis showed that an estimate of the milk‐production decline per percent increase in the prevalence of Bovine‐Leukosis virus in dairy cows accounted for most of the uncertainty in the economic‐impact estimates. If Bovine‐Leukosis virus had not been present in U.S. dairy cows, then milk production would have increased by 2.0 billion ± 1.5 billion kg, the price would have fallen by 3.8 ± 3.2 cents/kg, and the value of the milk produced would have decreased by 2.1 ± 1.9 bUS$. Guidelines delineated by the International Organization for Standardization, for evaluating and expressing uncertainty in measurement, are discussed and proposed for use in the context of broad national estimates, for which the economic impacts of Bovine‐Leukosis virus serve as an example. The principal advantages of the methodology are the clarity and transparency of results, and the ability clearly to identify major uncertainty contributors.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号