NEGATIVE SUPPLY RESPONSE AND THE ROLE OF PRICE EXPECTATIONS IN A TWO-PERIOD MODEL OF CATTLE PRODUCTION

This paper incorporates a representation of producers' price expectations (ARIMA) in a two-period production process to characterise short-run cattle supply. The model provides a framework for examining the role of biological factors and changing expectations of future cattle prices in generating a negative short-run supply response. The biological link between cattle generations requires the farmer to make a decision between production today and production tomorrow. This decision is based on a trade-off between the possibilities of increasing current profit levels by increasing current output weighted against the possibilities of increased future profit by maintaining animals in inventory under the expectation of future price increases. Application of the model to Canadian data for the period 1978-81 shows that the necessary condition for a negative supply response exists, but that the total supply elasticity remains positive.     

农民专业合作社农户合作意愿分析 —基于杨凌现代农业示范园的实证研究

通过对杨凌示范区现代农业示范园42家农民专业合作社的实地调研,运用二元Logistic模型对调研数据开展分析,从农户个体特征、农户心理特征、合作社特征和政府公共服务等探究影响农民合作意愿的主要因素。结果显示,农民的合作意愿主要源于现代农业发展的需要,尤其是面临现代农业经营中难题时,农户更迫切需求合作组织的帮助。同时发现地方政府对农民的合作意愿影响很大。基于这些实证研究,提出了一些政策建议。     

A MODEL OF SUPPLY RESPONSE IN THE AUSTRALIAN ORANGE GROWING INDUSTRY*

A model of the Australian orange growing industry to explain changes in plantings, removals, the number and age composition of trees and orange production is developed and estimated. Most of the variation in plantings is explained by the expected profitability of growing oranges, the current stocks of bearing and nonbearing trees, and removals of trees last year. Estimates of the elasticities of response of plantings and production to price changes are low and there are long time lags. An illustrative application of the model projects future developments in the industry for alternative assumptions about the profitability of growing oranges.     

A MICRO-ECONOMIC APPROACH TO THE ANALYSIS OF SUPPLY RESPONSE IN BRITISH AGRICULTURE

Most of the work undertaken on the estimation of supply response in U. K. agriculture has been based on the analysis of time-series data. However, there are a number of problems associated with an analysis of aggregate supply response for British agriculture based on time-series analysis alone. This paper reports on an alternative supply response model being developed at Newcastle in which estimates of aggregate supply levels are built up from optimal programmes for a set of representative farms.     

贺兰山东麓银川地区酿酒葡萄农业气候资源对气候变化的响应

[目的]为合理利用农业气候资源,主动适应气候变化提供依据。[方法]基于宁夏银川地区1961-2015年地面气象观测资料,明确了酿酒葡萄生长季内主要农业气候资源、影响酿酒葡萄品质的主要农业气候因子及主要农业气象灾害的演变特征。[结果]近55年银川日平均气温稳定通过10℃起始时间提前,结束时间显著推迟,日平均气温稳定通过10℃持续时间显著增加,每10年分别增加97.6℃和2.6d,尤其是1995年后积温出现了明显增加。近55年酿酒葡萄适宜的放条出土时间提前,可能的生长季呈显著延长趋势,生长季内热量资源显著增加。近55年酿酒葡萄全生育期内日照时数呈显著减少趋势,生育期内日较差均呈不显著的减少趋势,但在酿酒葡萄适宜生长范围内。最热月(7~8月)平均气温显著增加,每10年增加0.28℃,不利于酿酒葡萄优良品质的形成。酿酒葡萄采收前1个月(9月)降水量及降水日数表现为增加趋势,对品质形成不利。不同级别霜冻及越冬冻害发生频率有所减少。[结论]热量资源增加为晚熟品种的成熟提供了保证,但是霜冻及越冬冻害依然不容忽视。     

AN APPLICATION AND EXTENSION OF THE MARKOV CHAIN MODEL TO CEREAL PRODUCTION

Given aggregate time-series data, conventional Markov Chain estimation of the stationary transition probabilities is performed for a model of the cereal market in Great Britain. The possibility of non-stationary probabilities is examined in the light of these initial results, and the basic model developed to allow exogenous variables to enter via their influence on these parameters. The evidence from the paper would appear to suggest that, at least in the case considered, time-varying transition probabilities are a most attractive alternative.     

ESTIMATION OF A PRODUCTION FRONTIER MODEL: WITH APPLICATION TO THE PASTORAL ZONE OF EASTERN AUSTRALIA

This paper considers a statistical model for a production frontier that is consistent with the traditional (nonstochastic) definition of a production function given in microeconomic theory. Limiting cases of the model are the familiar average production function and an envelope production function. Maximum-likelihood estimators for the parameters of the model are defined. The three related models are applied in the estimation of a production frontier for the Pastoral Zone of Eastern Australia with use of data from the Australian Grazing Industry Survey.     

AN EXAMPLE OF A HEURISTIC LEARNER IN A SIMULATION MODEL

This article deals with the use of a heuristic learner in a simulation model. Simulation modes do not lend themselves to optimizing algorithms thus the use of search procedures are very important when employing a similation model. This paper brings together the concepts of probability and entropy in the use of a learner for simulation models. The learner in this study uses past information as its source upon which to base the next economic decision. Once the decision is made then the outcome of that decision is used to direct the learner for the next decision. This type of learning is consistent and useful for experimental design such as simulation.
Cette article concemc ľusage de ľassimilation intellectuelle heuristique dans une modèle de simulation. Les modèles de simulation ne se prêtent pas a ľoptimation des algorithmes, mais ľusage des mèthodes de recherche sont très importante quand il s'agit ďntiliser des modèles. Ce document rassemble les concepts de probabilité et ďintropée dans ľusage de ľassimilation intellectuelle pour des modèles de simulation. Dans cette étude ľassimilation intellectuelle utilise les informations antécédentes comme référence, et on y base les décisions economiques ulterieurs. Ces décisions prises, les résultats serviront à orienter ľassimilation intellectuelle lors des prochaines décisions. Ce type ďassimilation intellectuelle est logique et utile au model expérimental comma celui de la simulation.     

A MODEL OF NEW ZEALAND APPLE SUPPLY RESPONSE TO TECHNOLOGICAL CHANGE*

A supply response model for New Zealand apples is specified and equations for new plantings, removals, yields and adoption of an innovation are estimated. The model expands on perennial crop models previously estimated by incorporating the time pattern of adoption of a planting innovation and formulation of a measure of yield expectations given technological change.     

THE RETURNS TO INVESTMENT IN RESEARCH ON AUSTRALIAN WOOL PRODUCTION*

A production function approach is used to estimate growth in farm productivity in the Australian wool industry from an estimated level of expenditure on wool production R & D. A market equilibrium model of the wool industry is then used to measure the share of total benefits from this productivity growth accruing to Australia and its wool growers. A net return is estimated after allowing for lags in the development and adoption of technology.     

农户参加农民专业合作社行为影响因素研究 ———以日照市为例

农民专业合作社既可以降低农户独自经营的生产成本和面临的风险,又能提高农产品的市场价格,但是目前我国农户加入农民专业合作社的比重较低。通过实地调查和实证研究,该文分析了影响我国农户参加农民专业合作社行为的影响因素,并给出了相应的政策建议。即加大宣传,增强农户对农民专业合作社的认知;加大对专业合作社的支持力度;转变追求数量目标,集中力量重点支持规范合作社做强做好。     

A SHORT-RUN MODEL FOR FORECASTING MONTHLY EGG PRODUCTION IN CANADA1

A model for predicting the monthly egg production in Canada at least six months in advance is developed in this paper. The model is based on simulating the egg production involving its various stages and making use of technical as well as economic relationships. The model can forecast egg production up to five months in advance using available prices: for a period beyond this lime projection of prices becomes essential. During the period 1965–1969, the forecasted level of production came within ±5 percent range of the actual. Un modèle pour prédire la production mensuel ?oeufs au Canada au moins six mois ?avance est révélé dans cette étude. Le modèle est basé sur la simulation de la production ?oeufs comprennanl ses différents étapes, et ulilisant des relations techniques ou economiques. Le modèle prevoie la production ?oeufs jusquà cinq mois ?avance ulilisant les prix disponibles; pour un temps hors de ce temps, la projection de prix devient essentiel. Pendant ?éspace de temps 1965–1969, le plan de production prèvenue est venue entre plus ou moins la classe de cinq pourcent de ?actuel.     

农业综合开发项目扶持农民专业合作社发展研究 ———以浙江省为例

农业综合开发项目作为农民专业合作社发展的一个重要财政资金来源,对于促进我国农民专业合作社的发展起到了重要作用.该文以浙江省为例,对于农业综合开发项目在扶持农民专业合作社发展中存在问题进行了研究,并提出了相应的对策建议.     

A SIMULATION APPROACH TO THE ANALYSIS OF STABILISATION POLICIES IN AGRICULTURAL MARKETS: A CASE STUDY*

Agricultural markets are very often susceptible to year-to-year fluctuations in price and output and it is generally agreed that it would be desirable to control these fluctuations by intelligent market support operations. In this paper we develop a simulation model to assess the efficacy of market support operations in the case of egg market in the U.K. during the period 1958-68. We argue that for this problem a simulation approach is more effective than either a geometric or an algebraic approach. On the basis of our analysis, we find that in the absence of the market support operations of the British Egg Marketing Board during the period 1958-68, the long-run average return to the egg producer would have been only marginally different from the actual but the instability of the market would have been substantially greater. We also found that because of the nature of the subsidy arrangements, there were severe limits to the Egg Board's capacity to increase producer price even in the short run in spite of the inelastic demand curve. More generally, we conclude that marketing Boards in situations similar to the Egg Board's should aim at keeping close to the long-run producer price rather than short-run profit maximisation.     

浙江省农村土地流转模式初探

根据江苏省农村土地使用权流转的新特点,系统分析了委托经营制、股份经营制和互换制等几种土地流转模式,最后提出了若干完善和浙江省土地流转创新的对策与建议。     

粮食主产区农户节水灌溉采用意愿分析

黑龙江垦区已形成科学农业节水体系,但广大市县节水灌溉率非常低,大多采用传统漫灌方式.该文依据黑龙江省364个市县农户的调查数据,运用logit模型对农户采用节水灌溉技术意愿的影响因素进行分析,结果表明:种植业收入所占比重、政府扶持、耕地面积、年龄等因素具有正相关作用.最后提出构建节水灌溉技术推广的投融资体制、加大政府补贴力度、构建农户农业用水激励机制、扩大农户的耕地规模等政策建议.     

A FARM GROWTH MODEL FOR POLICY ANALYSIS IN AN EXTENSIVE PASTORAL PRODUCTION SYSTEM

The development of a simulation model of an extensive pastoral farming system to assist analysts in their assessment of government policy measures is described. The model was designed to simulate, over a number of years, the physical and financial operation of a sheep and beef production system typically found in the North Island hill country of New Zealand. By manipulating model parameters and data related to prices, costs, taxation and credit, a range of policies can be represented and their effects simulated. The model is used to undertake an ex post analysis of the farm-level impact of the supplementary minimum price scheme in New Zealand and to project farm performance following the abolition of the scheme. Consideration is given to the use of the model to represent sheep and beef production systems elsewhere.     

农业生产托管推进小农生产现代化的逻辑创新

[目的]“大国小农”是我国的基本国情、农情,未来我国农业现代化的难点是如何实现小农户生产经营现代化。针对现阶段小农户发展现代农业面临的“谁来种地”“如何种好地”“种地如何赚钱”等问题提出改进措施,从而为进一步丰富农业生产托管实践路径提供借鉴。[方法]文章采用理论研究、实证研究和案例研究相结合的方法,从推进生产托管服务主体联合、推动小农户组织化、满足农户个性化生产经营需求、健全小农户与市场主体的利益联结机制、建立农业生产托管的风险分担机制等五个方面,系统梳理农业生产托管推进小农生产现代化的逻辑创新。[结果]农业生产托管一定程度上起到了将小农户引入现代农业发展轨道的作用,提高了农业生产效率,同时也巩固了农户家庭经营的主体地位,没有将小农户排斥在现代农业发展的轨道之外。[结论]提出灵活推进各种规模化经营模式、提升小农户组织化程度、培育农业生产托管供需市场等改进措施。