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 781 毫秒
1.
The disciplinary nature of most existing farm models as well as the issue specific orientation of most of the studies in agricultural systems research are main reasons for the limited use and re-use of bio-economic modelling for the ex-ante integrated assessment of policy decisions. The objective of this article is to present a bio-economic farm model that is generic and re-usable for different bio-physical and socio-economic contexts, facilitating the linking of micro and macro analysis or to provide detailed analysis of farming systems in a specific region. Model use is illustrated in this paper with an analysis of the impacts of the CAP reform of 2003 for arable and livestock farms in a context of market liberalization. Results from the application of the model to representative farms in Flevoland (the Netherlands) and Midi-Pyrenees (France) shows that CAP reform 2003 under market liberalization will cause substantial substitution of root crops and durum wheat by vegetables and oilseed crops. Much of the set-aside area will be put into production intensifying the existing farming systems. Abolishment of the milk quota system will cause an increase of the average herd size. The average total gross margin of farm types in Flevoland decreases while the average total gross margin of farms in Midi-Pyrenees increases. The results show that the model can simulate arable and livestock farm types of two regions different from a bio-physical and socio-economic point of view and it can deal with a variety of policy instruments. The examples show that the model can be (re-)used as a basis for future research and as a comprehensive tool for future policy analysis.  相似文献   

2.
The direct payment system of the Common Agricultural Policy (CAP) provides income transfers to European farmers. Recently, several countries including England and Sweden have advocated the elimination of direct payments after 2013. The extent to which an elimination of direct payments would affect the land use dynamics in Europe including impacts on structural change and the environment has not been addressed in the existing literature. In this paper, we combine participatory methods, to analyze regional preferences for functions and effects of agriculture, and farm-level modeling, to assess the impacts of such a policy change on farm structures and land use intensities in four European regions located in Germany, Denmark, Italy and Poland, each with different socio-economic and biophysical characteristics. In each region, the entire farm population consisting of different farm types with different production orientations and land management types was modeled under the presence and absence of direct payments using a combination of agent-based and bio-economic modeling. We found that the initial characteristics of the regions, such as the historical farm structure and regional site conditions, greatly influence the impact of direct support elimination and cause regionally different development trends. The results for the four regions were summarized in four specific storylines that emphasize how much the diversity of European regions matters for future policy decisions. An explicitly regional focus is, therefore, argued to be crucial to complement future policy analysis.  相似文献   

3.
《Agricultural Systems》1998,58(3):285-307
During the past decades, major changes have taken place with regard to the available policy instruments for food security and rural development. These changes are reviewed against the background of the structural adjustment programmes carried out in the agricultural sector. The linkages between agricultural policy and farmers' supply response are discussed, emphasizing the influence of macro-policy for decision-making at the micro-level of a farm household. An integrated bio-economic modelling framework is presented that allows a better understanding of the effects of macro and sectoral policy interventions for food security and sustainable land use at the farm and (sub)regional level. Critical areas where the understanding of macro–micro linkages is still weak are identified. Major conclusions regarding a suitable analytical framework for policy analysis and support are presented.  相似文献   

4.
Bio-economic models can be used to assess the impact of policy and environmental measures through economic and environmental indicators. Focusing on agricultural systems, farmers’ decisions in terms of cropping systems and the associated crop management at field scale are essential in such studies. The objective of this paper is to present a study using a bio-economic model to assess the impact of the Nitrate Directive in the Midi-Pyrenees region (France) by analyzing, at the farm scale, farm income and three environmental indicators: nitrate leaching, erosion and water consumption. Two scenarios, the 2003 CAP reform (baseline scenario) and the Nitrate Directive (policy scenario), with a 2013 time horizon, were developed and compared for three representative arable farm types in the Midi-Pyrenees region. Different types of data characterizing the biophysical context in the region (soil, climate), the current cropping systems (rotation, crop management) and farm resources (irrigated land, labor) were collected to calibrate and run the models. Results showed that the implementation of the Nitrate Directive may not affect farm income. However, significant modifications to cropping systems and crop allocation to soil types were simulated. Contrary to expectations, nitrogen leaching at the farm scale did not change. Overall water consumption increased and soil erosion decreased due mainly to a modification in cropping patterns and management by soil type. This study provides an example of unanticipated effects of policy and trade-offs between environmental issues.  相似文献   

5.
We present an integrated spatially explicit land use modeling framework, which integrates two key components of agricultural systems, the bio-physical production system and the management system, by coupling the bio-economic farm optimization model FAMOS[space], the crop rotation model CropRota, and the bio-physical process model EPIC (Environmental Policy Integrated Climate). The integrated modeling framework has been developed to analyze the cost-effectiveness of selected agri-environmental program (AEP) measures. We also focus on the landscape development and therefore include a detailed representation of landscape elements such as fields or orchard meadows in our analysis. An indicator set represents all main environmental AEP objectives, i.e. preservation of water and soil resources, mitigation of climate change, protection of biodiversity, maintenance of cultural landscapes as well as farm income support. The integrated modeling framework is applied to 20 farms in the Austrian ‘Mostviertel’ region, which are selected from the Integrated Administration and Control System (IACS) of the European Union. The cost-effectiveness of AEP measures is assessed under different premium levels. The implementation of the AEP clearly affects environmental quality in a positive way. Nitrogen rates are reduced, landscape elements can be sustained, and the landscape becomes more diverse. The program also increases farm gross margins on average. However, the cost-effectiveness ratios (CER) are declining with increasing premium levels. The results indicate that the cost-effectiveness of AEP measures can be improved by spatial targeting.  相似文献   

6.
《Agricultural Systems》1998,58(3):465-481
This article presents a bio-economic modelling approach for the assessment of the effectiveness of different agrarian policies to improve farm household income and soil fertility. Farm household decisions on allocation of land, labour and capital resources for crop and production technique choice are simulated, taking into account resource availability, household objectives and prevailing market conditions. The modelling framework relies on a combination of three procedures: (1) farm household modelling, (2) linear programming, and (3) partial equilibrium analysis. These procedures are applied to evaluate the impact at farm household and regional level of technology improvement and a variety of policy instruments: improvement of infrastructure, price support, land policy and credit schemes. Regional aggregation allows prices to be determined endogenously on regional markets. The approach is applied to the Cercle de Koutiala in Mali, for which selected results are given as an example. Results indicate that technology alone cannot sufficiently induce farmers to adopt sustainable production systems. Additional economic incentives are necessary to foster technological change.  相似文献   

7.
We used a farm-level modeling approach to estimate on-farm compliance costs and environmental effects of a grassland extensification scheme in the district of Ostprignitz-Ruppin, Germany. The behavior of the regional farm population (n = 585) consisting of different farm types with different production orientations and grassland types was modeled under the presence and absence of the grassland extensification scheme using the bio-economic model MODAM. Farms were based on available accountancy data and surveyed production data, while information on farm location within the district was derived from a spatial allocation procedure. The reduction in total gross margin per unit area was used to measure on-farm compliance costs. A dimensionless environmental index was used to assess the suitability of the scheme to reduce the risk of nitrate-leaching.Calculated on-farm compliance costs and environmental effects were heterogeneous in space and farm types as a result of different agricultural production and site characteristics. On-farm costs ranged from zero up to almost 1500 Euro/ha. Such high costs occurred only in a very small part of the regional area, whereas the majority of the grassland had low on-farm costs below 50 Euro/ha. Environmental effects were moderate and greater on high-yield than on low-yield grassland. The low effectiveness combined with low on-farm costs in large parts of the region indicates that the scheme is not well targeted. The soft scheme design results from an attempt to achieve environmental and rural development objectives with only one scheme. Improving the efficiency of the scheme would require designing separate instruments for the two distinct objectives. This is in line with the Tinbergen rule, which states that consistent economic policy requires that the number of instruments equals the number of targets.  相似文献   

8.
《Agricultural Systems》1998,58(3):331-349
Interdisciplinary approaches to identify suitable incentives for enhancing sustainable natural resource use require an analytical framework that satisfies both practical purposes of policy support and disciplinary requirements regarding the specification of underlying technical and behavioural relations. Different approaches for agricultural policy analysis are distinguished according to the nature of problems addressed and the analytical procedures applied. Major drawbacks of more disciplinary analysis can be circumvented through functional integration of these approaches. The methodological foundations of an integrated bio-economic modelling framework for the simultaneous appraisal of agro-ecological and socio- economic parameters are presented, and assumptions on farm household decision making regarding crop and technology choice, labour use, market exchange and price responsiveness are discussed. Implications of this integrated approach are analysed against the background of policy discussions on land markets, incentives for innovation, and public investment for agricultural intensification. Policy analysis for sustainable land use proves to be critically dependent on the specification of the linkages between decision-making procedures regarding resource allocation by farm households and their supply response to changes in the economic and institutional environment.  相似文献   

9.
Tactical adjustments to seasonal weather conditions and beef price may generate additional income or avoid losses in French beef cattle farms. Due to the length of the suckler cow production cycle, adjustment decisions may impact not only on current production and profit but also on future farm outcomes. To better understand the consequences of shocks and subsequent production adjustments on the evolution of farm earnings and production over time, we built a dynamic recursive bio-economic farm model. Our model introduced simultaneously the possibility of adjusting herd size and herd composition, diet composition and diet energy content, as well as crop rotation, haymaking and feed stocks, taking into account both their short- and long-term consequences. An application is provided to test impacts of crop yield and beef price shocks of different intensities. Main simulated adjustments to face unfavourable weather shocks are (1) purchased feed in order to maintain animal production objectives, and (2) area of pasture harvested for haymaking. Very severe beef price shocks induce forced sales. Weather shocks affect farm net profit not only of the current year but also of the following years. Profit losses caused by unfavourable weather conditions are not compensated by gains in favourable ones and this differential is amplified when intensity of shocks rises.  相似文献   

10.
《Agricultural Systems》1999,59(3):311-325
Sustainability is a human-centred concept that comprises multiple aspects and objectives of different interest groups. Sustainable development is not readily measurable, except as a compromise between different parts of society, of which some may try to represent future generations of mankind. To determine a sustainable development path in the relationship between agriculture and its natural environment, a profound knowledge of this complex system and its behaviour under different socio-economic conditions is necessary. We present a modelling system which consists of a set of hierarchically linked modules. These modules describe production activities in a way that allows an economic and ecological analysis of these techniques. The heart of the modelling system is a multiple goal linear programming model, which is generated by data base modules. Simulation of single farm models as well as regional models based on simultaneously optimised farm types is possible. The modelling system appears to be a highly flexible tool with respect to the number and type of farms, sites and production techniques. Environmental objectives can easily be included and different levels of goal achievement can be simulated. It is well suited for single farm analysis as well as for regional models, for static as well as dynamic approaches. It allows rapid adoption of the model and rapid calculation of scenarios. Therefore, it is suited for use in interactive environments with users which are interested in repeated runs with little changes in the goal function, prices, subsidies or technical coefficients. The results can be used for policy decisions as well as the strategic planning of individual farmers. Applications of the modelling system will be presented in following papers. In this paper the kind of information the model can generate and the circumstances of their usage are shown. ©  相似文献   

11.
《Agricultural Systems》2005,83(3):251-276
Agricultural production in the semi-arid agro-ecosystems of the Sahel centres on cereal staple crops and pastoralism with increasing crop–livestock integration. Animals mobilize soil fertility through manure production, graze crop by-products, and transfer nutrients from distant pastures to cropped areas. Yet in these systems various interacting factors, i.e. climate variability, poor soil fertility, poverty, and institutional constraints limit the capacity of agriculture to keep pace with the growing needs of an increasing human population.The major trends associated with population growth are (1) increasing area cropped at the expense of rangelands; (2) reduced availability of and access to good quality grazing resources, and (3) seasonal migration of labourers and transhumance of herds. These trends lead to co-evolution of farming systems towards increased privatisation of resource use.This study examines the implications of the development processes where farming systems co-evolve with their surroundings. It explores the impact of integrated management of livestock and crops in rural communities on both the livelihoods of differently endowed farms, and on the agro-ecosystem. Different scenarios explored the co-evolution of three sites situated in Western Niger with their environment. The sites differ in relative area cropped. The scenarios simulate the different future outcomes for varying socio-economic and biophysical criteria with either current or more intensive management.Explorative bio-economic models are used to compare a range of farm, livelihood and ecological indicators, and to reveal social and ecological trade-offs.If current agro-ecosystems and their environments co-evolve towards increased privatisation of grazing resources, then soil fertility is likely to deteriorate on the lands managed by the agro-pastoral groups. Soil fertility may improve on lands managed by the livestock-scarce farmers settled in villages, at the cost of declining farm incomes. The agro-pastoral groups are likely to resort to more distant pastures for feed. The village-based, livestock-endowed farms will resort to feeding on on-farm crop residues. Intensification, though associated with relative decreases in real incomes, will enhance food security in these new systems, except for the poorer settled farmers.  相似文献   

12.
《Agricultural Systems》1998,58(1):25-37
Resource limits for weather dependent constraints in farm planning models are often implemented as chance constraints. Procedures for setting right-hand sides for these constraints are often based on rules of thumb which are seldom updated. This paper presents an approach for validating these rules of thumb, and demonstrates the approach for a heavily used farm planning model. An evaluation of the robustness of chance constraints for equipment availability which are dependent on good (sufficiently dry) field time, is presented. Rules for setting constraints affected by good field time were found to be dependent on the tillage system(s) under consideration. These results imply a need for more research on setting availabilities of stochastic resources under alternative tillage systems.  相似文献   

13.
African farming systems are highly heterogeneous: between agroecological and socioeconomic environments, in the wide variability in farmers’ resource endowments and in farm management. This means that single solutions (or ‘silver bullets’) for improving farm productivity do not exist. Yet to date few approaches to understand constraints and explore options for change have tackled the bewildering complexity of African farming systems. In this paper we describe the Nutrient Use in Animal and Cropping systems - Efficiencies and Scales (NUANCES) framework. NUANCES offers a structured approach to unravel and understand the complexity of African farming to identify what we term ‘best-fit’ technologies - technologies targeted to specific types of farmers and to specific niches within their farms. The NUANCES framework is not ‘just another computer model’! We combine the tools of systems analysis and experimentation, detailed field observations and surveys, incorporate expert knowledge (local knowledge and results of research), generate databases, and apply simulation models to analyse performance of farms, and the impacts of introducing new technologies. We have analysed and described complexity of farming systems, their external drivers and some of the mechanisms that result in (in)efficient use of scarce resources. Studying sites across sub-Saharan Africa has provided insights in the trajectories of change in farming systems in response to population growth, economic conditions and climate variability (cycles of drier and wetter years) and climate change. In regions where human population is dense and land scarce, farm typologies have proven useful to target technologies between farmers of different production objectives and resource endowment (notably in terms of land, labour and capacity for investment). In such regions we could categorise types of fields on the basis of their responsiveness to soil improving technologies along soil fertility gradients, relying on local indicators to differentiate those that may be managed through ‘maintenance fertilization’ from fields that are highly-responsive to fertilizers and fields that require rehabilitation before yields can improved. Where human population pressure on the land is less intense, farm and field types are harder to discern, without clear patterns. Nutrient cycling through livestock is in principle not efficient for increasing food production due to increased nutrient losses, but is attractive for farmers due to the multiple functions of livestock. We identified trade-offs between income generation, soil conservation and community agreements through optimising concurrent objectives at farm and village levels. These examples show that future analyses must focus at farm and farming system level and not at the level of individual fields to achieve appropriate targeting of technologies - both between locations and between farms at any given location. The approach for integrated assessment described here can be used ex ante to explore the potential of best-fit technologies and the ways they can be best combined at farm level. The dynamic and integrated nature of the framework allows the impact of changes in external drivers such as climate change or development policy to be analysed. Fundamental questions for integrated analysis relate to the site-specific knowledge and the simplification of processes required to integrate and move from one level to the next.  相似文献   

14.
《Agricultural Systems》2005,86(1):29-51
The methodology presented in this paper aims at analysing whether there is room for improvement of vegetable farmers’ income in Canelón Grande (Uruguay), while reducing soil erosion and improving physical and biological soil fertility, and to gain insight in the influence of farmers’ resource availability on the opportunities for sustainable development. The (generic) approach we developed to support re-design of farming systems in this region is unique in dealing with complex temporal interactions in crop rotations and spatial heterogeneity on farms in one integrated method, while revealing trade-off between economic and environmental objectives. Rather than an arbitrary sub-set, all feasible crop rotations were generated, using a tool named ROTAT. The crop rotations were combined with a range of production techniques according to pre-defined design criteria to create a wide variety of alternative production activities at the field scale. We used process-based simulation models supplemented with empirical data and expert knowledge to quantify inputs and outputs of production activities. We developed a mixed integer linear programming model (MILP), named Farm Images, to allocate production activities to a farm with land units differing in soil quality, while maximising or minimising socio-economic and environmental objectives, subject to constraints at the farm level. Production activities comprised current practices as well as activities new to the area. We used Farm Images to design farm systems for seven existing farms in Canelón Grande with different resource availability. The farm systems designed by the model had higher family income than current systems for six of the seven farms studied. The estimated average soil erosion per ha decreased by a factor of 2–4 in the farm systems proposed compared to the current systems, while the rate of change of soil organic matter increased from negative in the current systems to +130 to +280 kg ha−1 yr−1 in the proposed farm systems. The degree to which the objectives could be achieved was strongly affected by farm resource endowment, i.e., particularly by the fraction of the area irrigated, soil quality and labour availability per ha. The study suggests that decreasing the area of vegetable crops by introducing long crop rotations with pastures and green manure during the inter-crop periods and integrating beef cattle production into the farm systems would often be a better strategy than the actual farmers’ practice.  相似文献   

15.
Agriculture in the Punjab province of eastern Pakistan benefits from one of the largest canal irrigation systems in the world. The typical mixed holding is a small, 5 ha mixed farm with three-quarters of its land used for cash crops, such as rice, wheat and sugarcane, and the remainder growing forages such as lucerne and berseem for dairy animals. Both cows and buffaloes are used for milk production, with the latter the more productive. Despite irrigation, productivity is constrained by a slow uptake of new technology such as fertilisers and new plant varieties, and poor livestock management, which leads to extended calving intervals, and a lack of available capital. This study used LP models, constructed with original local data on milk and crop production activities, to investigate the effect on profitability of alleviating the main constraints. The results demonstrate the powerful effect of using better, well managed dairy livestock, of increasing the uptake of simple technological improvements and of widening access to credit. They also show the synergy between these elements, for example the importance of finance as part of any intervention strategy. The results should enable agricultural development policy makers to rank the changes and devise better targeted programmes to deliver the changes on farm.  相似文献   

16.
Sustainable use (in terms of nutrients) of soil resources by farmers in Sub-Saharan Africa is constrained by institutions and markets. This paper explores the case of northern Nigeria, by using a combination of multi-attribute utility theory and bio-economic modelling. This approach allowed us to identify heterogeneity in production strategies and to quantify its effect on the use of soil nutrient resources.We find that farmers with larger land holdings place more emphasis on gross margins in their utility function, while those with larger holdings of fertile fadama fields place more emphasis on sustainability. Risk aversion, operationalised through variance minimization, appears an important attribute in the utility function of many farm households that are more dependent on agriculture for their overall income.A regression analysis shows that differences in production strategies significantly affect nutrient balances, but also shows that such effects are heterogeneous across locations. We find more favourable nutrient balances for some of the more market-oriented farm households who place more emphasis on sustainability. In farm plans of the most risk-averse households, the production of cereals for subsistence consumption dominates and leads to negative soil nutrient balances, especially for potassium.Farmers who place a large importance on gross margins are likely to benefit most from policies aimed at enhancing profitability through improving functioning of markets. The large group of risk-averse farmers will have the largest immediate gain in utility from policies and technologies aimed at reducing production risk in high-value crops. Additional policies aimed at creating a stronger market-oriented production by the least-endowed farm households could play a role in reducing intensity of soil fertility mining. Under these conditions, the efficient cropping pattern shifts partially from cereal cropping to high-value crops, associated with higher input use.The main results are similar to those in other studies, although some of the nutrient balances are less negative. The results do appear to be sensitive to the type of cropping activities included in the analysis, and additional methodological research is required. Extensions of the used method should further account for temporal and spatial differences in soil fertility, leading to differences in nutrient uptake and production, as well as potential temporal heterogeneity in production strategies.  相似文献   

17.
Excessive irrigation and nitrogen applications result in substantial nitrate leaching into groundwater in intensively cropped oases in desert areas of Alxa, Inner Mongolia. An integrated modelling approach was developed and applied to compare policy incentives to reduce nitrate leaching. The integrated model consists of a process-based biophysical model, a meta-model, a farm economic model and an assessment of policy incentives. The modelling results show that there are “win-win” opportunities for improving farm profitability and reducing nitrate leaching. We found that 4471 Yuan ha−1 of farm gross margin could be obtained with a reduction in nitrate leaching of 373 kg ha−1. Farmers’ lack of knowledge about water and nitrogen in soil, and on crop requirements for water and nitrogen could explain the differences, so that agricultural extension is an appropriate policy incentive for this area. When the economic optimum is obtained reductions in nitrate leaching are not achievable without profit penalties and there is a “trade-off” relationship between farm profitability and groundwater quality protection. The combination of low elasticity of nitrate leaching and large elasticity of farm gross margin against water price increases results in very high costs for reducing nitrate leaching (105.6 Yuan kg−1). It is suggested that if the water price increases were coupled with subsidies for adopting nitrate leaching mitigation practices, environmental gains could come at a lower cost.  相似文献   

18.
19.
《Agricultural Systems》2005,85(1):42-58
Domestic milk production has been for a long time hindered by many factors including lack of interest from decision makers, distorted economic policy and biotechnical constraints. For the last 20 years, many developing countries have been attempting to develop the domestic milk production sector. However, research on the basic realities and the viability status of enterprises within this sector remain largely unproved in many developing countries. This study focuses on the characteristic of smallholder milk producers in The Gambia. Data were collected from 90 smallholder farm households to characterise milk producers and evaluate the profitability and viability status of this activity. Based on current typology of farms and gross margin analyses at farm level, the study identified two resource-based types of smallholder farms. The current milk production system is surely viable. Constraints to increased productivity include lack of improved technology at farm level and weak institutional support. Despite the low viability status, it is shown that milk production generates reliable incomes, which could be a departure for most farmers to intensify farming systems, particularly in areas where no loan schemes exist for purchasing agricultural inputs.  相似文献   

20.
Olive farming on sloping land in southern Europe is facing multiple challenges and it is reasonable to believe that farmers will opt for the abandonment of some systems and intensification or change to organic production of other systems. The issues at stake surpass financial farm viability and two EU policy instruments - cross-compliance and agri-environmental measures (AEM) - are available to address environmental objectives. This paper explores how cross-compliance and AEM policy options may lead to shifts in olive production systems and their social and environmental effects in Trás-os-Montes, NE Portugal over 25 years under two sets of conditions of uncertainty: decision-making by land users and market scenarios. Uncertainty in decision-making is addressed by employing five alternative goal programming models. The models include Linear Programming (LP), Weighted Goal Programming (WGP) and MINMAX Goal Programming (MINMAX GP), the GP variants of which are moreover formulated from a societal (S) and farmer (F) perspective. Uncertainty in market prospects is addressed by projecting olive oil and labour prices and trends in farm subsidies, distinguishing four price combinations in market scenarios. The models were validated by their capability to reproduce the initial configuration of olive production systems. Six policy options are evaluated under the complete ranges of uncertainty factors in a total of 6 × 5 × 4 = 120 model runs. Results show overall large effects of farmer decision-making and market scenarios. The cross-compliance and AEM policy instruments have an unequivocal effect on environmental performance and help to maintain work in rural areas. However, farmer income levels are insensitive to the policies, all work is absorbed by family labour and important environmental issues linked to more intensive systems such as pollution are not addressed. In a case study with the WGP (F) model which best reproduced the initial configuration of production systems, cross-compliance was moreover found to burden farmers under adverse market conditions, while AEM contributed to farmer’s objectives under favourable market conditions. A solution would be to focus cross-compliance regulations on intensive systems and offer appropriate AEM for traditional or abandoned orchards. Both policy instruments proved effective, but there is scope for removing substantial overlap between them.  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