PREDICTING WHEAT ACREAGE IN THE PRAIRIE PROVINCES

Two models incorporating distributed lags are used to forecast next year's acreage of wheat to be harvested in the Prairie Provinces.     

NDVI在农作物监测中的研究与应用

归一化差值植被指数(normalized difference vegetation index,NDVI)是农作物监测中应用最为广泛的光谱参数之一,在农作物生产与管理中具有重要的实际指导意义.该文就NDVI在作物产量、生物量、收获指数、叶面积指数、营养状况、作物冻害等方面的研究与应用作一综述,并总结当前研究中存在的问题与不足,提出了NDVI在今后作物监测中进一步的研究重点.     

THE LOCATION OF MAINCROP POTATO PRODUCTION IN BRITATN-AN APPLICATION OF LINEAR PROGRAMMING

In any dynamic economy the allocation of resources, particularly land, is in need of continual reappraisal in order to reduce their misallocation. For some years now linear programming and similar operational research techniques have been applied to solving problems of this nature within the agricultural economy. In this paper interregional competition within the potato industry is analysed using the framework of the transportation algorithm. Problems of specification and data compilation are discussed. Three models are then formulated, their solutions illustrated, and comparisons made with the present distribution of production in order to arrive at conclusions as to possible areas of adjustment. Finally, some of the strengths and weaknesses of the methodology used are outlitled.     

ESTIMATING THE DEMAND FOR WATER IN COMMERCIAL AGRICULTURE*

The foundation of the demand for water in agriculture is the water response functions of the various crops grown. As the productivity of water is largely determined by the lime at which a crop is irrigated, both intra-seasonal and seasonal demand schedules for water exist for the firm and so for the region. The efficient interregional allocation and pricing of water between users may be assessed using spatial equilibrium models. While a profit maximising objective may be valid for the firm, as the level of an analysis moves to the regional or the inter-regional complex, increasing attention must be paid to non-economic goals which must be incorporated within societies' objective. La demande ?eau dans ?agriculture se base sur les fonctions du besoin ?eau des récolies différents. Tandis que la productivité de ?eau est déterminé en grande parlie selon la saison pendant laquelle une récolle est irriguée, des programmes de demande intra-saisonnier et saisonnier pour ?eau existe pour ?exploitation, ainsi que pour la région. ?allocation efficace au niveau inter-régional et ?établissement ?un prix pour ?eau parmi les utilisateurs peuvent être évalués en se servant de modèles ?equilibre spatial. Tandis qu'un but de maximisation de profit peut être valide pour ?exploitation. au moment ou une analyse comprend le systems régional ou inter-regional, il faut aussi considérer les buts non-économiques qui doivent etre incorporés dans les objectifs sociaux.     

MEASURING THE EFFECT OF WEATHER ON CROP PRODUCTIO*

Farm income is greatly affected by the impact of weather on crop production. Relating crop production to weather requires an index that is relatively specific to a local area. A single index is preferable in economic analysis to avoid including many weather variables that may be highly intercorrelated and to preserve degrees of freedom for testing the models chosen. The unique feature of the reported index is the use of readily available data and the direct estimation of the effect of weather on yield per acre. The resulting weather index was found to be reasonably accurate, and thus suitable for use in studies concerned with such diverse topics as the benefits of environmental control and the stability of farm income.
WE ANALYSE DBS CONDITIONS CLIMATIQUES SUR LE RENDEMENT DES CULTURES. — Le revenu agricole est grandement affectée par les conditions climatiques sur le rendement des récoltes. Le rapport entre les deux demande un indice qui relate particulièrement à une région précise. Un seul indice est preferable dans l'analyse économique afin d'éviter d'y inclure trop de variables qui pourraient être et de préserver un dégré de liberté dans l'application des modèles choisis. L'unique caractéristique de cet indice est l'emploie des données disponibles et une évaluation juste des conditions climatiques sur le rendement à l'acre des cultures. Les résultats sur l'indice des conditions climatiques semblent être très efficace, ainsi convenable à l'usage des études concernant les avantages d'un contrôle de milieu et de la stabilité du revenue agricole.     

ESTIMATING SOURCES OF FLUCTUATIONS IN THE AUSTRALIAN WOOL MARKET: AN APPLICATION OF VAR METHODS

Vector autoregression (VAR) methods are used to analyse the contribution of supply, demand and policy shocks to unpredictable fluctuations in the market for Australian wool. VAR procedures are compared with conventional structural econometric models as methods for decomposing sources of instability. While each has advantages and disadvantages, VAR procedures might be viewed as preferable when the underlying market structure is complex and uncertain, as it is in the case of wool. Based on the results obtained, demand shocks are the dominant source of uncertainty in the wool market in the absence of Australian Wool Corporation intervention, but intervention has blunted their effects, reducing market uncertainty and increasing the average level of prices and revenues.     

PROFIT MAXIMISATION AND IMPERFECT COMPETITION—AN APPLICATION OF QUADRATIC PROGRAMMING TO HORTICULTURE*

This paper discusses the determination of profit-maximising behaviour under conditions of imperfect competition in product and/or factor markets. After stating a quadratic programming model which restricts product demand and factor supply functions to a linear form, an empirical application to a New Zealand nursery firm is discussed. It is concluded that such quadratic programming models should have an important role to play in horticultural management     

中国粮食作物种植变化对省际农业碳排放量的影响研究

目的 农业碳排放是影响生态环境的重要因素之一,促进我国省际间农业碳排放的相对均衡发展,对加快农业生产中“双碳”目标实现具有重要的现实意义。方法 文章基于1991—2019年粮食作物农用物质投入等统计数据,运用IPCC碳排放系数法,测算粮食主产区和主销区农业碳排放量,运用固定效应模型分析检验我国农业碳排放量的影响因素。结果 （1）我国粮食作物播种面积整体稳定,播种区域逐渐向粮食主产区集中;（2）我国农业碳排放总量持续增加但增速下降,化肥、柴油是主要碳源,碳排放量、碳源及碳排放强度在粮食主产区和粮食主销区差异明显;（3）粮食作物种植面积比重增加对农业碳排放量有明显增进作用,农业效率提高和农业结构优化对碳排放有抑制作用,农业经济发展水平则促进农业碳排放量增长。结论 应加快农业现代化进程,提高农业生产效率;强化化肥、农药、柴油等化学生产要素投入科学标准和使用技术,提高使用效率;实施碳排放补贴政策,建立碳排放区域间补偿机制。     

THE USE OF A DECISION MAKER'S UTILITY FUNCTION IN A LINEAR PROGRAMMING ANALYSIS OF AGRICULTURAL POLICY*

A decision theoretic approach to agricultural policy decision making is examined to discover whether a utility function of an Australian Wool Corporation decision maker can be established and, if so, whether this can be used to improve the policy analysing performance of an agricultural sector linear programming model. After discussing the theoretical requirements of the utility function elicitation and the elicitation procedures, the characteristics of the resulting functions are examined. A means for its inclusion in a linear programming framework is described and some analysis of policy is carried out. The general conclusions are that the relevance of the agricultural sector analysis is enhanced by the use of such a utility function.     

OPTIMAL FEEDING POLICIES FOR BROILER PRODUCTION: AN APPLICATION OF DYNAMIC PROGRAMMING*

The determination of an optimal feeding and selling strategy for broiler production given a space constraint is formulated as a dynamic programming problem. Production equations derived from trial data are used to obtain an optimal sequence of rations in which energy density changes through time. The stability of the plan is explored and the implications of the results for production research and commercial practice are considered.     

遥感技术在水产养殖规划中的应用研究

本文简要介绍了遥感技术在渔业方面应用的经验以及未来发展前景、可能带来的社会效益和经济效益。     

ESTIMATING THE IMPACT OF BEEF IMPORT RESTRICTIONS IN THE US IMPORT MARKET

A beef import model is specified and estimated using disequilibrium econometrics. The statistical significance of the model suggests that disequilibrium has historically existed in the US beef import market. Surplus analysis based on the disequilibrium framework indicates that a welfare loss has been incurred as a result of the quota and associated voluntary restraint programmes that have existed in that market.     

AN ANALYSIS OF WILLINGNESS-TO-PAY FOR CROP INSURANCE*

In this paper a method for estimating a producer's willingness-to-pay for crop insurance is presented. The method includes formulae to capture the impact of crop insurance on the producer's expected income and variance of income. These impacts are evaluated in the context of a model of producer welfare which features both price and yield uncertainty, as well as risk aversion on the part of the producer. The method is applied to the Australian wheat industry and estimates of willingness-to-pay are shown to be relatively sensitive to the levels of coverage and yield variability.     

CONCEPTUAL AND EMPIRICAL ISSUES IN ESTIMATING TRANSFER CHARGES*

Despite growing interest in interregional analysis, little effort to date has been devoted to estimation and selection of transfer charges for use in interregional studies when alternative modes of transport are involved. The usual procedure is to select the one mode of transport for each route that corresponds to the lowest quoted transfer charge. Under certain conditions this method is shown to have produced biased results. In such cases, a combined-cost procedure is proposed in which alternative transfer charges (corresponding to alternative modes of transport) are combined to form a weighted average transfer charge for each route, with the weights based on the average use made of each mode for actual shipments. The suggested procedure, which is outlined in detail, recognizes the existence of other service and cost factors in transportation in addition to quoted rates. QUESTIONS CONCEPTUELLES ET EMPIRIQUES CONCERNANT LE CALCUL DES FRAIS DE TRANSBORDEMENT–En dépit de ?intérêt croissant dans ?analyse interrégionale, peu ?efforts ont été consacrés jusqu'ici au calcul et au choix des frais de transbordement à employer dans les études interrégional lorsque des modes de transport différents sont concernés. La procédure habituelle est de choisir le mode de transport pour chaque route qui correspond au frais de transbordement fixés les plus bas. Sous certaines condition, cette méthode se trouve à produire des résultats inexacts. Dans de tels cas, une procédure de coûts ?ensemble est proposée dans laquelle les frais différents de transbordement (correspondant aux modes différents de transport) sont réunis pour former une moyenne pondérée des frais de transbordement pour chaque route, les coefficients de pondération étant basés sur ?usage moyen que ?on fait de chaque mode pour les expéditions réelles. La procédure suggérée, qui est élaborée en détail, reconnaît ?existence ?autres facteurs de service et coût dans le transport en plus des taux fixés.