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1.
Modern commercial agriculture is characterised by rapid technological change. These new technologies complicate decision-making for farm managers. Effective decision-making in this environment requires a systematic means of evaluation—one that attempts to evaluate the consequences of various management and production choices before resources are committed. The systems model described in this paper is considered to be an important step in this direction. The model provides a means for testing new production alternatives for cereal and oilseed crops in western Canada without actual farm application and thus of eliminating some of the trial and error associated with conventional decision-making methods. It does not replace the farm manager as the decision maker but it does provide information to facilitate his management function. 相似文献
2.
The factors influencing the decision of smallholder farmers to adopt new farming technologies were studied with reference to rubber–tea intercropping in Sri Lanka. Rubber–tea intercropping has been recommended previously to rubber farmers as a means to improve productivity and income during the early pre-tapping phase of rubber growth. Although crop trials have shown that the two crops are agronomically compatible and potentially produce a combined economic yield superior to the yield of a sole crop grown on the same area of land, there is little evidence of widespread adoption of this practice among smallholder farmers in Sri Lanka. The aim of the study was to determine the major factors that influence the decision to undertake rubber–tea intercropping and to construct a predictive model that describes the likelihood of adoption of intercropping by traditional smallholder rubber growers. A rapid rural appraisal (RRA) was undertaken based on semi-structured interviews of 90 smallholder farmers in the main rubber growing low wet zone of Sri Lanka. Among a number of factors shown to significantly influence the decision to intercrop tea with rubber, three were shown to operate independently, namely level of income, source of income (i.e. solely from own farm or from farm plus additional off-farm enterprises), and availability of land considered suitable for tea cultivation. A statistical model developed through correlation and logistic analysis, which predicts the likelihood of a smallholder adopting intercropping based on these factors, is presented and discussed. The most likely combination of circumstances (82% probability) under which rubber–tea intercropping is practiced is shown to be where the farmer’s income is greater than Rs. 10,000 per month, where the farmer’s income is based solely on own farm enterprises, and where more than 80% of the farmer’s land area was judged to be suitable for tea cultivation. Conversely, 30% of smallholder farmers that chose not to intercrop did possess land suitable for tea cultivation. Qualitative responses to the RRA indicated that limitation of technical knowledge was the main problem subsequently faced by rubber farmers who had adopted rubber–tea intercropping. Results indicate that there is need for both income support through farm subsidies and further agricultural extension services, if rubber–tea intercropping is to be adopted more widely in Sri Lanka. The wider usefulness of the developed logistic model in determining the likelihood of adoption of intercropping by smallholder farmers is discussed. 相似文献
3.
Economic analysis of drought risk: An application for irrigated agriculture in Spain 总被引：1，自引：0，他引：1
This paper describes a two-part methodology for managing the risk posed by water supply variability to irrigated agriculture. First, an econometric model is used to explain the variation in the production value of irrigated agriculture. The explanatory variables include an index of irrigation water availability (surface storage levels), a price index representative of the crops grown in each geographical unit, and a time variable. The model corrects for autocorrelation and it is applied to 16 representative Spanish provinces in terms of irrigated agriculture. In the second part, the fitted models are used for the economic evaluation of drought risk. Inflow variability in the hydrological system servicing each province is used to perform ex-ante evaluations of economic output for the upcoming irrigation season. The model's error and the probability distribution functions (PDFs) of the reservoirs’ storage variations are used to generate Monte Carlo (Latin Hypercube) simulations of agricultural output 7 and 3 months prior to the irrigation season. The results of these simulations illustrate the different risk profiles of each management unit, which depend on farm productivity and on the probability distribution function of water inflow to reservoirs. The potential for ex-ante drought impact assessments is demonstrated. By complementing hydrological models, this method can assist water managers and decision makers in managing reservoirs. 相似文献
4.
Jonathan Vayssires Franois Guerrin Jean-Marie Paillat Philippe Lecomte 《Agricultural Systems》2009,101(3):128-138
Crop-livestock farms are complex systems. The interactions operating in such systems involve decisional, biophysical, structural, and environmental factors. Moreover, as farmers face a large range of management options, tools are needed to support their decision-making to enable them to reach production levels meeting their objectives and compatible with their human and physical resources, while controlling their effects on the environment. Gamede, a whole-dairy-farm model, has been developed to explore this complexity and to represent dynamically the effect of management decisions on biomass and nitrogen flows and on numerous sustainability indicators, such as milk and forage crop productivity, labour requirements, nitrogen balance, and nitrogen efficiency.This article describes the integration of six modules accounting for biophysical processes in a dairy farm (forage production; forage conditioning; herd demography; milk, excreta and animal biomass productions; grazing, quality of fertilisers; and nitrogen gaseous emissions) together with a decision system accounting for the farmer’s strategy and technical operations. Most of the six biophysical modules incorporate mathematical models from the literature, but the decision system stems from our own original work.Six commercial farms with different structures, agro-climatic conditions and management strategies were used for validation. The model can explain the differences found in their sustainability indicators at the year scale. The intra-year variability of the main biomass stocks and flows is also well explained. This quantitative validation was completed by a qualitative validation from researcher, adviser and farmer points of view, including simulations of prospective scenarios. 相似文献
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E.D. Cittadini M.T.M.H. Lubbers N. de Ridder H. van Keulen G.D.H. Claassen 《Agricultural Systems》2008
In South Patagonia, Argentina, sweet cherry is the main fruit-tree crop grown for export, resulting in a highly seasonal labour demand. Managers of deciduous perennial fruit orchards must consider both biological and economic relationships in selecting crop species and orchard design. This makes decisions at the farm-level extremely complex, as especially in such perennial crops, strategic (‘what to plant’, ‘with which technology’ and ‘how much area of each activity’, i.e. the final design) and tactical (‘when, what and how to plant in time’, the pathway to the planned farm) decisions have a long-term effect. The objective of this study was to explore the consequences of different strategic and tactical decisions at farm scale in fruit production systems of South Patagonia, considering the variation in interests and aims of different stakeholders, and using a sensitivity analysis to evaluate the consequences of possible changes in external conditions. A dynamic farm-scale optimization model called OPTIFROP was developed to generate alternative farm development plans, by allocating, in the course of the time horizon of the run, production activities to different land units, while optimising different objective functions, subject to several constraints. Although time-dependent, dynamic, mathematical programming models for analysing farming systems have been described in literature, the dynamic aspects of long-term decision-making in orchard design and their impact on the sequential (annual) nature of orchards in different growth phases (i.e. medium-term decision-making), need a higher time-staged dynamic approach with a staircase matrix structure. The model includes two objective functions at farm level: (1) maximization of the present value of cumulative financial result, which is the main objective for growers, and (2) maximization of cumulative farm labour, which is an objective often mentioned by policy makers. The inter-months deviation for labour demand (during the period of high labour demand, November–April) was included as an upper-bound. Input and output coefficients for the land use options considered in OPTIFROP were quantified using the Technical Coefficient Generator FRUPAT. Model results indicated that the present value of cumulative financial result and the cumulative farm labour are conflicting to a very limited extent. Timing and feasibility of implementing certain combinations of production technologies are affected by resource endowments and initial conditions, but these factors do not influence land use selection in the long term. Land use selection is driven by the objectives of the stakeholders. OPTIFROP showed that, through introduction of alternative crops, substantial reductions in labour peaks in the period November–April could be achieved with a relatively small reduction in farm income. The sensitivity of the model solution to the cherry price suggests that the fruit production sector of South Patagonia should pay more attention to the robustness of their land use plans and take preventive measures to avoid being caught by a possible crisis due to changes in the context. 相似文献
7.
Increasing profits and reducing risks in crop production using participatory systems simulation approaches 总被引：1，自引：0，他引：1
H. Meinke W. E. Baethgen P. S. Carberry M. Donatelli G. L. Hammer R. Selvaraju C. O. Stckle 《Agricultural Systems》2001,70(2-3):493-513
The development of cropping systems simulation capabilities world-wide combined with easy access to powerful computing has resulted in a plethora of agricultural models and consequently, model applications. Nonetheless, the scientific credibility of such applications and their relevance to farming practice is still being questioned. Our objective in this paper is to highlight some of the model applications from which benefits for farmers were or could be obtained via changed agricultural practice or policy. Changed on-farm practice due to the direct contribution of modelling, while keenly sought after, may in some cases be less achievable than a contribution via agricultural policies. This paper is intended to give some guidance for future model applications. It is not a comprehensive review of model applications, nor is it intended to discuss modelling in the context of social science or extension policy. Rather, we take snapshots around the globe to ‘take stock’ and to demonstrate that well-defined financial and environmental benefits can be obtained on-farm from the use of models. We highlight the importance of ‘relevance’ and hence the importance of true partnerships between all stakeholders (farmer, scientists, advisers) for the successful development and adoption of simulation approaches. Specifically, we address some key points that are essential for successful model applications such as: (1) issues to be addressed must be neither trivial nor obvious; (2) a modelling approach must reduce complexity rather than proliferate choices in order to aid the decision-making process; (3) the cropping systems must be sufficiently flexible to allow management interventions based on insights gained from models. The pro and cons of normative approaches (e.g. decision support software that can reach a wide audience quickly but are often poorly contextualized for any individual client) versus model applications within the context of an individual client's situation will also be discussed. We suggest that a tandem approach is necessary whereby the latter is used in the early stages of model application for confidence building amongst client groups. This paper focuses on five specific regions that differ fundamentally in terms of environment and socio-economic structure and hence in their requirements for successful model applications. Specifically, we will give examples from Australia and South America (high climatic variability, large areas, low input, technologically advanced); Africa (high climatic variability, small areas, low input, subsistence agriculture); India (high climatic variability, small areas, medium level inputs, technologically progressing; and Europe (relatively low climatic variability, small areas, high input, technologically advanced). The contrast between Australia and Europe will further demonstrate how successful model applications are strongly influenced by the policy framework within which producers operate. We suggest that this might eventually lead to better adoption of fully integrated systems approaches and result in the development of resilient farming systems that are in tune with current climatic conditions and are adaptable to biophysical and socio-economic variability and change. 相似文献
8.
Conventional water management in the Crau plain needs to be modified to ensure higher irrigation efficiency, better crop production and quality, and reduced environmental impacts. Because experimental approaches to test modifications of water management are difficult in relation to border irrigation, simulation may provide an alternative. We describe the development of a conceptual model of the decision-making process that determines the irrigation management of a cropping system, on which a simulation model is to be based. Interviews focused on water management were carried out, to understand how farmers manage their irrigation and how their decisions determine the technical system applied on the farm. These interviews were then analyzed using the “model for action” concept, to generate a conceptual model of the decision system, which is organized as a sequence of decision rules describing irrigation management. This model contains five elements: (1) spatial and temporal factors relevant to decision-making in terms of irrigation and hay cropping; (2) no interaction between the grassland cropping system and the sheep rearing system; (3) five rules to describe irrigation management in the cropping system; (4) major water distribution constraints; and (5) two inter-related operations, hay mowing and irrigation. The rules for irrigation decision-making are written as: “If <Indicator><Operator><Threshold> Then <Action1> Else <Action2>”. This conceptual model was used as the basis of a decision support system that includes models of grass growth and hydrology. 相似文献
9.
模糊决策采用隶属函数描述客观事物差异中亦此亦彼的模糊现象差异的大小程度,是多目标决策中的重要方法之一。各影响因素权重确定是该方法的重要环节,如何排除确定过程中的人为因素,使权重确定更加合理、更符合内在规律性是需要深入研究的问题,本文基于Uazy提出的多目标模糊决策权重敏感性分析数学基础与理论,采用均匀试验设计这种多因素多水平的试验设计方法提出了一种开展多因素模糊决策权重敏感性分析的方法与理论,并以某滑坡物理模型试验相似材料配比研究中的模糊决策权重敏感性分析验证了其合理性与重要性,这对丰富模糊多目标决策方法具有一定的现实意义和理论价值。 相似文献
10.
Gregory E. Frey Hugo E. FassolaA. Nahuel Pachas Luis ColcombetSantiago M. Lacorte Oscar PérezMitch Renkow Sarah T. WarrenFrederick W. Cubbage 《Agricultural Systems》2012,105(1):21-32
Farmers’ perceptions over time of an agroforestry technology can have an important impact on adoption and disadoption. Their perceptions, in turn, may be influenced by the type and scale of farm they own and the social networks they create. We examined the factors underlying producers’ perceptions of silvopasture systems at the time of adoption and perceptions following several years of experience, and the factors explaining discontinuance of systems in Argentina. We found that while most adopters indicated that other people influenced their decision about whether or not to adopt silvopasture, the type of person that influenced them (professionals vs. other farmers) did not affect adopters’ perceptions of the relative benefits and challenges of the system. However, farm scale and farm type did explain farmers’ perceptions to a good degree. Smaller-scale farmers were less likely to see costs and returns as benefits of the system, but more likely to see cash flow properties as important advantages. Farmers’ perceptions after experiencing the system were good predictors of likely discontinuance, but influential people, farm scales, farm type, and perceptions at the time of adoption were not. 相似文献
11.
This paper explores the use of analytic hierarchy process (AHP) for selecting an appropriate irrigation method. A sample of farmers was separated into four groups using cluster analysis. A panel of experts utilized AHP to determine the priority of three irrigation methods (border, basin and sprinkler) for each group of farmers. The findings indicated that the highest priority of irrigation methods differed with respect to farmers groups. The appropriateness of the decision of each farming group, regarding selection of irrigation methods, was determined. In 74% of cases, experts confirmed the farmer’s decision in selection of irrigation methods, but questioned the appropriateness of the decision for 26% of farmers. Recommendations are made for future use of decision tools to improve extension programs and farmers decision-making process. 相似文献
12.
Brigitte A. Kaufmann 《Agricultural Systems》2011,104(9):655-665
The notion that pastoralists are irrational managers due to strong adherence to tradition and culture is still common in livestock production sciences. Researchers and development practitioners tend to fall back on this notion when target groups do not adopt their proposed innovations without any obvious reason. It is however difficult to identify innovations that fit into resource-poor systems, and often this lack of fit is the reason why innovations are not taken up. Understanding why pastoralists do what they do, and learning about the constraints they face when regulating production processes, is a prerequisite for identifying viable improvement possibilities.This study focuses on understanding the reasoning behind pastoralists’ actions. The knowledge underlying pastoralists’ regulation of production processes is analysed with a method based on second-order cybernetics that offers insight in the system view of the actors in the system. It uses feedback and control principles of cybernetics to understand human control in human activity systems. For analysis purposes, a control loop model is proposed to systematically assess, for each management practice, the livestock keepers’ observations and the rules upon which they base their actions.This cybernetic knowledge analysis is illustrated using the example of milk offtake management in a pastoral camel production system in northern Kenya. The example is chosen because lack of knowledge on the complex milk offtake management led to the widespread preconception of poor pastoral management as the cause for high calf mortality.The cybernetic knowledge analysis reveals what livestock keepers consider as information in their production process, as well as the rules that inform their actions. The analysis enables to distinguish between management practices that serve as: (i) routine control; (ii) problem-solving control; or (iii) selection. This information is useful in transdisciplinary studies that involve local actors and other stakeholders in finding solutions to real-world problems. Through the proposed knowledge analysis methodology, scientists can learn about livestock keepers’ reasoning and problem-solving abilities, but also about aspects of the production processes where control is weak and new control possibilities are sought after. The analysis also yields information on how livestock keepers try to achieve their production goals despite restrictions and disturbances given by the production environment. This understanding is of high importance in low-external-input systems that have little scope to control production conditions but that do adapt to them. 相似文献
13.
Changes in the structure of agriculture are known to affect emissions of environmental pollutants from agriculture. Such changes are often driven by structural changes in agricultural production, so structural changes are likely to have indirect effects on emissions. In a pilot study, we consider how linking two complementary simulation models might be used to explore these effects. The agent-based AgriPoliS model was used to simulate the structural dynamics of agricultural production. The results from AgriPoliS were passed via a number of intermediate models to the Farm-N model, which was used to estimate the nitrogen surplus and losses from each farm for each year.The modelling complex was exercised by simulating the effects of two plausible policy scenarios for each of 14 years. The initial sizes and types of farms were based on statistics from a region in Denmark and the farms were randomly distributed within this region. The reference scenario (REF) implemented the current area-based Common Agricultural Policy payments for Denmark. The 1 LU scenario applied the additional constraint that a minimum area of 1 ha land had to be available for the application of the manure produced by one livestock unit.Substantial changes in the structure of agricultural production were shown for both scenarios. The effect on the regional nitrogen surpluses was predicted to differ between scenarios and the contribution of the different farm types to change with time. Predicted ammonia emission changed with time and differed between the scenarios, whereas the Danish fertiliser and manure legislation meant that nitrate leaching remained fairly stable.The implementation of additional environmental legislation significantly changed the trajectory of structural adjustment processes. Results emphasize the complex interplay between structural changes, losses of nitrogen, and environmental regulation.It is concluded that the effects of structural change on environmental emissions can be usefully explored by linking agent-based models of farmers’ investment decisions with other models describing nutrient losses from the farm and that such modelling can play a useful role in designing effective environmental policies for agriculture. However, the approach demands the availability or collection of many region-specific data and this could create a barrier to its use. 相似文献
14.
《Agricultural Systems》2003,76(1):253-272
A Markov decision sow model has been developed to represent the productive and reproductive lifespan of herd sows. This model precisely describes the herd structure at equilibrium based on actual farm data. Model outputs are the herd structure at equilibrium, and technical and economic indexes. Validation has been performed by comparing observed and simulated outputs from specific farm data. A complementary validation using a statistical χ2 test based on Pearson's statistic is proposed to compare herd distributions at equilibrium. The model is intended to be used by farmers and runs on micro computers. 相似文献
15.
《Agricultural Systems》2006,89(2-3):205-226
This paper explores the way in which dairy farmers perceive their environment (PE), i.e., the external context of their farm, and the uncertainty (PEU) this poses to them. The environment is defined using the STEP concept (society, technology, economy and politics) and Porter’s five forces model. The relationship between the perception of the external farm environment and the strategy farmers choose for their farm is quantified to gain insight into the effect of the external farm environment on decision-making. Data from a survey of 103 Dutch dairy farmers was analyzed using regression analysis. The results indicate that environmental uncertainty is not related to complexity or dynamism, but to the illiberality (i.e., intolerance, hostility) of the external farm environment. The institutional environment is considered especially illiberal, thus causing high uncertainty. Farmers with high PEU are more likely to choose a diversification strategy, while low perceived uncertainty results in a process-control strategy for the farm. A growth strategy is not affected by perceived environmental uncertainty. The PE and PEU approach is new in agricultural research and shows that the farmer’s view on the external environment is a key issue for decision-making on farms The significant relationship between the perceived uncertainty caused by the external farm environment and farm strategies shows that to get a good understanding of the farm, farming system boundaries should be expanded to incorporate the effect of the external farm environment on decision making. Reduction of uncertainty will enhance decision-making because instead of farming within an uncertain context, risk management practices can be used. 相似文献
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Crop area planning plays significant role in agricultural water management. During the planning, because of ambiguous or uncertain information caused by the vagueness of decision makers’ subjective preference or the uncertainty of objective information, conventional multi-objective linear programming (MOLP) model is not suitable for such decision-making in such fuzzy environment. In this study, we proposed the fuzzy multi-objective linear programming (FMOLP) model with triangular fuzzy numbers and transformed the FMOLP model and its corresponding fuzzy goal programming (FGP) problem to crisp ones which can be solved by the conventional programming methods. The FMOLP model was applied to crop area planning of Liang Zhou region, Gansu province of northwest China, and then the optimal cropping patterns under different water-saving levels and satisfaction grades for water resources availability of the decision makers (DM) were obtained. Compared to the MOLP model, the FMOLP model itself expresses the fuzzy information effectively, and its solutions can represent the DMs satisfactory degree of the subjective preference and propose alternative solutions for better decision support when applied in the crop area planning. 相似文献
18.
B. Sterk M.K. van Ittersum C. Leeuwis W.A.H. Rossing H. van Keulen G.W.J. van de Ven 《Agricultural Systems》2006
Whole-farm design models quantitatively analyze the effects of a variety of potential changes at the farm system level. Science-driven technical information is confronted with value-driven objectives of farmers or other social groupings under explicit assumptions with respect to exogenous variables that are important drivers of agricultural systems (e.g., market conditions). Hence, farm design is an outcome of objective specification and the potential of a system. In recent publications, whole-farm design modelling has been proposed to enhance (farm) innovation processes. A number of operational modelling tools now offers the opportunity to assess the true potential of whole-farm design modelling to enhance innovation. In this paper, we demonstrate that it is not trivial to find niches for the application of goal-based farm models. Model outcomes appeared not to match questions of farm managers monitoring and learning from their own and other farmers’ practices. However, our research indicates that whole-farm design modelling possesses the capabilities to make a valuable contribution to reframing. Reframing is the phenomenon that people feel an urge to discuss and reconsider current objectives and perspectives on a problem. Reframing might take place in a situation (i) of mutually felt dependency between stakeholders, (ii) in which there is sufficient pressure and urgency for stakeholders to explore new problem definitions and make progress. Furthermore, our research suggests that the way the researcher enters a likely niche to introduce a model and/or his or her position in this niche may have significant implications for the potential of models to enhance an innovation process. Therefore, we hypothesize that the chances of capitalizing on modelling expertise are likely to be higher when researchers with such expertise are a logical and more or less permanent component of ongoing trajectories than when these researchers come from outside to purposefully search for a niche. 相似文献
19.
《Agricultural Water Management》2006,86(3):269-276
Online decision support for irrigation has been available in Denmark since 1996. This paper describes an Internet implementation of a previous stand-alone PC-program; the Internet version has undergone several modifications and upgrades. The system has a morphological model for crop development based on temperature sums, and a hydrological model for calculating soil water balance. Weather data are supplied automatically from weather databases, precipitation data can be overrode by user inputs. Users can initiate the system with data on fields and crops, and add data on irrigations. Irrigation advice and explanation are provided in tables and graphics. The system had 322 active users in 2004 and 490 in 2005. 相似文献
20.
《Agricultural Systems》1999,59(3):245-255
DAIRYPRO is a combination decision support and expert system consisting of two modules. The system is designed to help dairy farmers in northern Australia make strategic decisions about their farm. It can be run by dairy extension officers as a consultation package for farmers. The system is based on a combination of statistical models developed from real farm survey data and opinions from experts in the field of dairy farming. The first module gathers together the data needed to run predictive models and the system of rules that enable the program to make estimates of regional average production (using predictive statistical models) and achievable production (using heuristics). These predictions can be compared to the farmer's actual production. Farmers are then encouraged to make hypothetical changes to the inputs on their farm, and `what-if' scenarios of increased or decreased milk production are displayed. The profit or loss associated with these changes is determined. The second module of DAIRYPRO uses the `rules of thumb' of an expert to determine how four pre-defined components of the dairy farm compare to optimum performance. These components are: the winter feeding program, summer feeding program, concentrate feeding program and capital and labour inputs. DAIRYPRO is a useful decision support package for dairy farmers, bank managers, loans officers and farm consultants. © 相似文献