共查询到20条相似文献,搜索用时 15 毫秒
1.
Crop‐livestock integration (CLI) to improve natural resource management for increased productivity is evolving in Nigeria and West Africa. Processes in the evolution and factors that influence it still need to be well understood. This article proposes and tests a new framework for measuring the multiple dimensionality of CLI. The framework derives a CLI index using the principal components of its most common single measures; it develops geographic information systems (GIS)‐based village‐level ecological and market factors; and it estimates parameters of factors affecting CLI using the derived index as the dependent variable in a Tobit model. The framework is tested using empirical data from 634 farm households in 11 geo‐referenced villages in the Sudan savanna (SS) and northern Guinea savanna (NGS), Nigeria. Along a north–south (SS to NGS) axis, CLI initially increases, peaking around 11.2°N, and then declines. This latitude probably identifies the boundary below which disease challenge constrains traditional livestock production and CLI. This polynomial pattern of CLI is contrary to an expected linear increase along lines of perceived potentials for rain‐fed crop production. Household resources, GIS‐derived village‐level market factors, and institutional factors also significantly affect CLI. Ecological and institutional factors have most impact on the probability of adoption and use intensities of CLI. The incorporation of GIS‐derived market factors with household and institutional variables in an econometric model offers new opportunities for assessing patterns of evolution of CLI, comparing results across sites, and targeting recommendation domains objectively. A comparison with results from more common methods of running independent models for individual indicators of CLI shows that this new framework is an effective way of reducing the multiple dimensionality of CLI to gain quicker, well‐focused knowledge of the processes of agricultural intensification. 相似文献
2.
Christoph Schmitz Hans van Meijl Page Kyle Gerald C. Nelson Shinichiro Fujimori Angelo Gurgel Petr Havlik Edwina Heyhoe Daniel Mason d'Croz Alexander Popp Ron Sands Andrzej Tabeau Dominique van der Mensbrugghe Martin von Lampe Marshall Wise Elodie Blanc Tomoko Hasegawa Aikaterini Kavallari Hugo Valin 《Agricultural Economics》2014,45(1):69-84
Changes in agricultural land use have important implications for environmental services. Previous studies of agricultural land‐use futures have been published indicating large uncertainty due to different model assumptions and methodologies. In this article we present a first comprehensive comparison of global agro‐economic models that have harmonized drivers of population, GDP, and biophysical yields. The comparison allows us to ask two research questions: (1) How much cropland will be used under different socioeconomic and climate change scenarios? (2) How can differences in model results be explained? The comparison includes four partial and six general equilibrium models that differ in how they model land supply and amount of potentially available land. We analyze results of two different socioeconomic scenarios and three climate scenarios (one with constant climate). Most models (7 out of 10) project an increase of cropland of 10–25% by 2050 compared to 2005 (under constant climate), but one model projects a decrease. Pasture land expands in some models, which increase the treat on natural vegetation further. Across all models most of the cropland expansion takes place in South America and sub‐Saharan Africa. In general, the strongest differences in model results are related to differences in the costs of land expansion, the endogenous productivity responses, and the assumptions about potential cropland. 相似文献
3.
The pressure on an already stressed water situation in South Africa is predicted to increase significantly under climate change, plans for large industrial expansion, ongoing rapid urbanization, and government programs to provide access to water to millions of previously excluded populations. This article employs a general equilibrium approach to examine the economy‐wide impacts of selected macro and water‐related policy reforms on water use and allocation, rural livelihoods, and economy at large. The analyses reveal that implicit crop‐level water quotas reduce the amount of irrigated land allocated to higher‐value horticultural crops and create higher shadow rents for production of lower‐value water‐intensive field crops, such as sugarcane and fodder. Accordingly, liberalizing local water allocation within irrigation agriculture is found to work in favor of higher‐value crops, and expand agricultural production and exports and farm employment. Allowing for water trade between irrigation and nonagricultural uses fuelled by higher competition for water from urbanization leads to greater water shadow prices for irrigation water with reduced income and employment benefits to rural households and higher gains for nonagricultural households. The analyses show difficult trade‐offs between general economic gains and higher water prices, which place serious questions on subsidizing water supply to irrigated agriculture, i.e., making irrigation subsidies much harder to justify. 相似文献
4.
Being the two largest ethanol producers in the world, biofuel policies in Brazil and the United States affect both their domestic markets and the global food and biofuel economy. In this article we develop a price endogenous mathematical programming model to simulate and analyze the impacts of biofuel mandates and trade distortions on land use, agricultural commodity and transportation fuel markets, and global environment. We find that an 80% increase in total biofuel production from its 103 billion liter baseline level to the mandated 183 billion liter level in 2022 can be achieved with less than 2% increase in total cropland use in both countries. In the United States, this would occur with cellulosic biofuels meeting nearly half of the biofuels consumed and produced largely on cropland pasture and corn ethanol meeting the rest of the mandate and resulting in a 2% increase in corn price. In Brazil, the expansion in sugarcane production would be achieved by reducing land under pasture and a marginal increase in intensification of livestock production. In the aggregate, biofuel policies increase economic surplus in both countries by 1% and redistribute the benefits from agricultural consumers to agricultural producers and the fuel sector. Finally, we also find that full implementation of the mandates in North America, China, and the European Union would reduce the global life‐cycle global greenhouse gas emissions by about 5%. 相似文献
5.
The proliferation of regional trade agreements in recent years has intensified the debate on the desirability of these agreements in themselves and their coexistence with multilateral free trade under the WTO. This study contributes to this debate by analyzing trade creation and trade diversion effects of the European Union on trade flows of six major agri‐food products from 1985 to 2000. An extended gravity model is estimated employing pooled data and generalized least squares methods. The results show that the developments in the EU since the mid‐1980s have served to boost agri‐food trade significantly among the members. Some of the growth in intra‐EU trade in agri‐food products came at the expense of nonmembers as the EU reduced the degree of relative openness to trade with nonmembers during this period and diverted trade from the rest of the world into the intra‐EU channels. 相似文献
6.
Many governments in developing countries distribute fertilizer at subsidized prices in an effort to stimulate small farmers' agricultural productivity and food security. Prior fertilizer demand studies have largely failed to account for the effects of government programs on farmers' commercial purchases. Using a double hurdle model and nationally representative rural household panel data in Zambia, we distinguish between these sources and measure the contemporaneous \"crowding in\" and \"crowding out\" effects of government input programs on commercial fertilizer sales. Where the private sector is relatively active and average wealth is higher (areas seemingly more likely to be targeted by government programs), results indicate that subsidies have substantially crowded out the private sector, in some cases to the point that such programs could actually lower overall fertilizer use. On the other hand, in poorer areas where the private sector is relatively inactive, subsidies help to generate demand and crowd in private sector retailers. Empirical studies explicitly modeling farmers' fertilizer purchase behavior within a dual marketing framework can provide important insights for agricultural policy discussions in developing countries. 相似文献
7.
This article is concerned with soil‐sustainability problems of agriculture in developing countries, in particular with soil erosion. The aim of our study is to develop a comprehensive model that explains the adoption of sustainable agricultural practices with respect to soil conservation. Our approach includes the following special features: (a) the model is comprehensive in that it includes a large number of institutional, personal–social, economic, and physical explanatory variables; (b) particular attention is paid to the influence of marketing systems on the adoption of sustainable agricultural practices, which to our knowledge has been neglected in past research; (c) the concept of adopting sustainable agricultural practices (ASAP) is differentiated into a limited number of basic components of soil conservation; and (d) the model is estimated by Principal Component Regression, which enhances efficient estimation of the impact of many explanatory variables on ASAP. Our model is applied to Cabuyal hillside farming in Colombia. The application demonstrates the usefulness of the proposed model. ASAP is differentiated into three basic components: soil‐disturbance control, soil‐protection practices, and run‐off control. It appears that soil‐disturbance control is particularly influenced by farmers' characteristics, such as education and managerial variables. The second component, soil‐protection practices, appears to be strongly influenced not only by farmers' managerial variables but also by their relationship with their environment, in particular marketing institutions. The third soil‐conservation component, run‐off control, is influenced by the physical characteristics of the plot and by the available farm labor. Our empirical results demonstrate the usefulness of the proposed model in designing agricultural policies, because it can determine which variables are more likely to influence the adoption of a specific type of soil conservation. 相似文献
8.
In this article, we analyze the role of subsistence‐oriented agriculture in Russia in the 1990s. We start out by discussing the diverging economic effects of the growth of subsistence agriculture in Russia since the transition process started. The quantitative analysis of this sector's role is carried out by means of an applied computable general equilibrium (CGE) model applying a 1994 social accounting matrix (SAM) as base year data. The novelty of the article is to disaggregate primary agricultural production not by products but by farm types, which enables us to distinguish their institutional and economic characteristics. The model also explicitly differentiates between marketed and subsistence consumption or formal and informal marketing activities of agricultural producers. We simulate two ex post and two ex ante experiments. The results of the first backward‐looking experiment highlight that Russia's subsistence agriculture was an important buffer against further agricultural output declines during transition and, hence, against food insecurity. A simulation, which looks into the effects of a devaluation of the Russian ruble, shows that the financial crisis should have increased the relative competitiveness particularly of large‐scale crop farms versus small‐scale farms. Two forward‐looking experiments indicate that efficiency enhancing institutional change would benefit both large‐scale and small‐scale farms. However, within small‐scale agriculture, a shift from subsistence to commercial agriculture would take place. 相似文献
9.
This research empirically investigates the well‐known “poor‐but‐efficient” hypothesis formulated by Schultz (1964) assuming that small‐scale farmers in developing countries are reasonably efficient in allocating their scarce resources by responding positively to price incentives. Deviating from Schultz it is assumed here that scale effects explain a considerable proportion of small‐scale farmers' relative efficiency. The theoretical underpinnings of the scale efficiency concept are briefly reviewed before a normalized generalized Leontief (GL) profit function is modeled by using its output supply and input demand system to capture the joint production of cassava flour and maize by a sample of small‐scale farmers in the Bragantina region of the Eastern Amazon, Brazil. The discussion of theoretical consistency and functional flexibility is considered by imposing convexity on the GL profit framework. The empirical results confirm our revised hypothesis that small farmers in traditional development settings are “poor‐but‐allocatively efficient” by clearly suggesting considerable inefficiency with respect to the scale of operations. 相似文献
10.
Hermann Lotze‐Campen Martin von Lampe Page Kyle Shinichiro Fujimori Petr Havlik Hans van Meijl Tomoko Hasegawa Alexander Popp Christoph Schmitz Andrzej Tabeau Hugo Valin Dirk Willenbockel Marshall Wise 《Agricultural Economics》2014,45(1):103-116
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
11.
Martin von Lampe Dirk Willenbockel Helal Ahammad Elodie Blanc Yongxia Cai Katherine Calvin Shinichiro Fujimori Tomoko Hasegawa Petr Havlik Edwina Heyhoe Page Kyle Hermann Lotze‐Campen Daniel Mason d'Croz Gerald C. Nelson Ronald D. Sands Christoph Schmitz Andrzej Tabeau Hugo Valin Dominique van der Mensbrugghe Hans van Meijl 《Agricultural Economics》2014,45(1):3-20
Recent studies assessing plausible futures for agricultural markets and global food security have had contradictory outcomes. To advance our understanding of the sources of the differences, 10 global economic models that produce long‐term scenarios were asked to compare a reference scenario with alternate socioeconomic, climate change, and bioenergy scenarios using a common set of key drivers. Several key conclusions emerge from this exercise: First, for a comparison of scenario results to be meaningful, a careful analysis of the interpretation of the relevant model variables is essential. For instance, the use of “real world commodity prices” differs widely across models, and comparing the prices without accounting for their different meanings can lead to misleading results. Second, results suggest that, once some key assumptions are harmonized, the variability in general trends across models declines but remains important. For example, given the common assumptions of the reference scenario, models show average annual rates of changes of real global producer prices for agricultural products on average ranging between ?0.4% and +0.7% between the 2005 base year and 2050. This compares to an average decline of real agricultural prices of 4% p.a. between the 1960s and the 2000s. Several other common trends are shown, for example, relating to key global growth areas for agricultural production and consumption. Third, differences in basic model parameters such as income and price elasticities, sometimes hidden in the way market behavior is modeled, result in significant differences in the details. Fourth, the analysis shows that agro‐economic modelers aiming to inform the agricultural and development policy debate require better data and analysis on both economic behavior and biophysical drivers. More interdisciplinary modeling efforts are required to cross‐fertilize analyses at different scales. 相似文献
12.
Trade policy, biotechnology and grain self-sufficiency in China 总被引:2,自引:0,他引:2
Fabrizio Felloni John Gilbert Thomas I. Wahl Philip Wandschneider 《Agricultural Economics》2003,28(3):173-186
Over the past 20 years the growth of China's agricultural economy has been extraordinary. However, it seems unlikely that China will maintain self‐sufficiency in grains by 2005 without substantial intervention. We develop a CGE model to assess the options available to Chinese policy makers. We compare the welfare effects of import tariffs and domestic support, and explore the potential of biotechnology as a means to achieve self‐sufficiency through improvements in agricultural productivity. Our results indicate that the price interventions that would be required to maintain China's desired self‐sufficiency ratios are considerable, and are unlikely to be compatible with WTO accession. The productivity improvements required are also significant, and likely beyond the current potential of biotechnology. 相似文献
13.
The proportion of agricultural production that is being transformed into biofuels has been growing worldwide over the last decade. This has spurred the food versus fuel debate. This article aims at shedding light on this issue by studying price volatility relationships between food and biofuel prices in Spain. We use an asymmetric MGARCH model to evaluate volatility spillovers between the Spanish biodiesel blend and refined sunflower oil prices. Empirical results confirm that there are bidirectional and asymmetric volatility spillovers between these two prices. 相似文献
14.
In an imperfectly competitive industry, differentiated products compete with each other with price rather than quantity as the strategic variable. Several previous studies have employed a generalized Nash–Bertrand model: Liang (1989) , Cotterill (1994) , Cotterill et al. (2000) , and Kinoshita et al. (2002) ; however, only Liang has explored the theoretical foundations of that model. This article generalizes the Liang two‐good model to three goods. A surprising and important result follows. Price‐conjectural variations do not exist in models with three or more goods. Price‐reaction functions, however, exist in multiple‐good models. We estimate them jointly with a brand‐level demand system to evaluate the total impact of a brand manager's price change on own quantity. In a differentiated product market, this is a useful addition to a partial demand elasticity approach, because a change in one brand's price typically engenders a price reaction by other brands that affects own quantity via substantial cross‐price elasticities among substitutes. Strategic pricing in the Boston fluid milk market was also influenced by the existence of a raw milk price support program, the Northeast Dairy Compact. We find that the advent of the Compact was a focal point event that crystallized a shift away from Nash–Bertrand to more cooperative pricing. If the downstream market is not competitive, one needs to consider strategic price reactions when designing and evaluating agricultural price programs. 相似文献
15.
Hugo Valin Ronald D. Sands Dominique van der Mensbrugghe Gerald C. Nelson Helal Ahammad Elodie Blanc Benjamin Bodirsky Shinichiro Fujimori Tomoko Hasegawa Petr Havlik Edwina Heyhoe Page Kyle Daniel Mason‐D'Croz Sergey Paltsev Susanne Rolinski Andrzej Tabeau Hans van Meijl Martin von Lampe Dirk Willenbockel 《Agricultural Economics》2014,45(1):51-67
Understanding the capacity of agricultural systems to feed the world population under climate change requires projecting future food demand. This article reviews demand modeling approaches from 10 global economic models participating in the Agricultural Model Intercomparison and Improvement Project (AgMIP). We compare food demand projections in 2050 for various regions and agricultural products under harmonized scenarios of socioeconomic development, climate change, and bioenergy expansion. In the reference scenario (SSP2), food demand increases by 59–98% between 2005 and 2050, slightly higher than the most recent FAO projection of 54% from 2005/2007. The range of results is large, in particular for animal calories (between 61% and 144%), caused by differences in demand systems specifications, and in income and price elasticities. The results are more sensitive to socioeconomic assumptions than to climate change or bioenergy scenarios. When considering a world with higher population and lower economic growth (SSP3), consumption per capita drops on average by 9% for crops and 18% for livestock. The maximum effect of climate change on calorie availability is ?6% at the global level, and the effect of biofuel production on calorie availability is even smaller. 相似文献
16.
Derek D. Headey 《Agricultural Economics》2016,47(Z1):185-196
Although land plays a crucially important role in economic development and structural transformation, the causes and consequences of the evolution of farming land have received scant attention in recent decades. In this article, I document global and regional changes in aggregate agricultural land use, per capita land use, and average farm sizes. The spatial distribution of global farming land has changed dramatically, with developed countries substantially reducing their share of global agricultural land, and land‐abundant developing countries substantially increasing their share. In per capita terms, we see a rather different pattern, with average farm sizes increasing in rich and more commercialized agricultural systems, and generally declining or staying constant in poorer and less commercialized systems. These outcomes are the result of complex processes that are not always well understood. I conclude the article by suggesting new, or neglected, areas of research that would facilitate a better understanding of these critically important developments. 相似文献
17.
Farmers in low‐income rural economies often fail to switch to cash crops from staple production despite the positive income effects of commercialization expected by policy makers. The literature suggests that market failures prevent households from cash crop adoption but remains inconclusive regarding farmers' motives and the effects of commercialization. This article contributes to the debate by offering an original approach to the analysis of commercialization outcomes and farmers' decisions. It consists of applying a model with essential heterogeneity and a semiparametric estimation technique to analyzing harvest value returns to cash cropping. Using Malawian data, we show considerable heterogeneity in harvest value returns to cash cropping both within and between groups of farmers choosing different crop portfolios. Importantly, the results imply rational choices based on comparative advantage considerations of farming households: farmers self‐select into the activity where they expect higher gains and adopt cash crops when facing weaker market barriers. 相似文献
18.
We identify critical stocks‐to‐use ratios (SURs) for major grains and for an index of total calories from these grains. The latter appears to be a promising indicator of vulnerability to large price spikes when the current price shows no cause for concern. More generally, our results suggest that stocks data, though no doubt unreliable, can be valuable complements to price data as indicators of vulnerability to shortages and price spikes. 相似文献
19.
In this study, we use the Harbinson Proposal and July Framework to compare a ‘likely’ Doha scenario with a realistic baseline. The novelty of this study is that we focus exclusively on the trade‐led welfare impacts in selected EU member states. The important features of this note are the: (i) usage of the latest Global Trade Analysis Project (version 6) data; (ii) focus on EU25 regions incorporating all major Common Agricultural Policy instruments and reforms; and (iii) inclusion of binding tariff overhangs into the Harbinson tariff reductions. Results show the damping effects of tariff‐binding overhangs on welfare outcomes. This and other factors which limit the gains to liberalisation mean that the EU25 only realises 10% of its long‐run welfare gain potential, as defined by complete liberalisation. 相似文献
20.
Pierre D. Ouattara Eugene Kouassi Aklesso Y. G. Egbendw Oluyele Akinkugbe 《Agricultural Economics》2019,50(3):329-339
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